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Versions: (draft-wen-l2sm-l2vpn-service-model) 00 01 02 03 04 05 06 07 08 09 10

L2SM Working Group                                                B. Wen
Internet-Draft                                                   Comcast
Intended status: Standards Track                        G. Fioccola, Ed.
Expires: January 4, 2018                                  Telecom Italia
                                                                  C. Xie
                                                           China Telecom
                                                                L. Jalil
                                                                 Verizon
                                                            July 3, 2017


              A YANG Data Model for L2VPN Service Delivery
                 draft-ietf-l2sm-l2vpn-service-model-02

Abstract

   This document defines a YANG data model that can be used to configure
   a Layer 2 Provider Provisioned VPN service.

   This model is intended to be instantiated at management system to
   deliver the overall service.  This model is not a configuration model
   to be used directly on network elements, but provides an abstracted
   view of the Layer 2 VPN service configuration components.  It is up
   to a management system to take this as an input and generate specific
   configurations models to configure the different network elements to
   deliver the service.  How configuration of network elements is done
   is out of scope of the document.

   The data model in this document includes support for point-to-point
   Virtual Private Wire Services (VPWS) and multipoint Virtual Private
   LAN services (VPLS) that use Pseudowires signaled using the Label
   Distribution Protocol (LDP) and the Border Gateway Protocol (BGP) as
   described in RFC4761 and RFC6624.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute




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   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 4, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     1.2.  Tree diagram  . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   6
   3.  The Layer 2 VPN Service Model . . . . . . . . . . . . . . . .   7
     3.1.  Applicability of the Layer 2 VPN Service Model  . . . . .   7
     3.2.  Layer 2 VPN Service Types . . . . . . . . . . . . . . . .   8
     3.3.  Layer 2 VPN Physical Network Topology . . . . . . . . . .   9
     3.4.  Layer 2 VPN Ethernet Virtual Circuit Construct  . . . . .  11
   4.  Service Data Model Usage  . . . . . . . . . . . . . . . . . .  13
   5.  Design of the Data Model  . . . . . . . . . . . . . . . . . .  15
     5.1.  Features and Augmentation . . . . . . . . . . . . . . . .  25
     5.2.  VPN Service Overview  . . . . . . . . . . . . . . . . . .  26
       5.2.1.  Customer Information  . . . . . . . . . . . . . . . .  27
       5.2.2.  VPN Service Type  . . . . . . . . . . . . . . . . . .  27
         5.2.2.1.  EVC . . . . . . . . . . . . . . . . . . . . . . .  28
         5.2.2.2.  OVC . . . . . . . . . . . . . . . . . . . . . . .  28
       5.2.3.  VPN Service Topology  . . . . . . . . . . . . . . . .  28
         5.2.3.1.  Route Target Allocation . . . . . . . . . . . . .  29
         5.2.3.2.  Any-to-Any  . . . . . . . . . . . . . . . . . . .  29
         5.2.3.3.  Hub and Spoke . . . . . . . . . . . . . . . . . .  29



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       5.2.4.  Cloud Access  . . . . . . . . . . . . . . . . . . . .  30
       5.2.5.  Metro Ethernet Network Partition  . . . . . . . . . .  31
       5.2.6.  Extranet VPNs . . . . . . . . . . . . . . . . . . . .  32
       5.2.7.  SVLAN ID Ethernet Tag . . . . . . . . . . . . . . . .  33
       5.2.8.  CVLAN ID Ethernet Tag . . . . . . . . . . . . . . . .  34
       5.2.9.  CVLAN ID To SVC MAP . . . . . . . . . . . . . . . . .  34
       5.2.10. Service Level MAC Limit . . . . . . . . . . . . . . .  35
       5.2.11. Load Balance Option . . . . . . . . . . . . . . . . .  35
       5.2.12. Service Protection  . . . . . . . . . . . . . . . . .  36
       5.2.13. Multicast Service . . . . . . . . . . . . . . . . . .  36
     5.3.  Site Overview . . . . . . . . . . . . . . . . . . . . . .  37
       5.3.1.  Devices and Locations . . . . . . . . . . . . . . . .  39
       5.3.2.  Signaling Option  . . . . . . . . . . . . . . . . . .  40
         5.3.2.1.  BGP L2VPN . . . . . . . . . . . . . . . . . . . .  41
         5.3.2.2.  BGP EVPN  . . . . . . . . . . . . . . . . . . . .  41
         5.3.2.3.  LDP Pseudowires . . . . . . . . . . . . . . . . .  41
         5.3.2.4.  PWE Encapsulation Type  . . . . . . . . . . . . .  42
         5.3.2.5.  PWE MTU . . . . . . . . . . . . . . . . . . . . .  42
         5.3.2.6.  Control Word  . . . . . . . . . . . . . . . . . .  42
         5.3.2.7.  L2TP Pseudowires  . . . . . . . . . . . . . . . .  43
       5.3.3.  Site Network Accesses . . . . . . . . . . . . . . . .  43
         5.3.3.1.  Bearer  . . . . . . . . . . . . . . . . . . . . .  44
         5.3.3.2.  Connection  . . . . . . . . . . . . . . . . . . .  44
     5.4.  Site Role . . . . . . . . . . . . . . . . . . . . . . . .  47
     5.5.  Site Belonging to Multiple VPNs . . . . . . . . . . . . .  47
       5.5.1.  Site VPN Flavor . . . . . . . . . . . . . . . . . . .  47
         5.5.1.1.  Single VPN Attachment: site-vpn-flavor-single . .  47
         5.5.1.2.  MultiVPN Attachment: site-vpn-flavor-multi  . . .  48
         5.5.1.3.  ENNI: site-vpn-flavor-enni  . . . . . . . . . . .  48
       5.5.2.  Attaching a Site to a VPN . . . . . . . . . . . . . .  49
         5.5.2.1.  Referencing a VPN . . . . . . . . . . . . . . . .  50
         5.5.2.2.  VPN Policy  . . . . . . . . . . . . . . . . . . .  50
     5.6.  Deciding Where to Connect the Site  . . . . . . . . . . .  53
       5.6.1.  Constraint: Device  . . . . . . . . . . . . . . . . .  54
       5.6.2.  Constraint/Parameter: Site Location . . . . . . . . .  54
       5.6.3.  Constraint/Parameter: Access Type . . . . . . . . . .  56
       5.6.4.  Constraint: Access Diversity  . . . . . . . . . . . .  56
     5.7.  Route Distinguisher and Network Instance Allocation . . .  58
     5.8.  Site Network Access Availability  . . . . . . . . . . . .  59
     5.9.  SVC MTU . . . . . . . . . . . . . . . . . . . . . . . . .  60
     5.10. Service . . . . . . . . . . . . . . . . . . . . . . . . .  60
       5.10.1.  Bandwidth  . . . . . . . . . . . . . . . . . . . . .  60
       5.10.2.  QoS  . . . . . . . . . . . . . . . . . . . . . . . .  61
         5.10.2.1.  QoS Classification . . . . . . . . . . . . . . .  61
         5.10.2.2.  QoS Profile  . . . . . . . . . . . . . . . . . .  62
       5.10.3.  Multicast  . . . . . . . . . . . . . . . . . . . . .  63
     5.11. Site Management . . . . . . . . . . . . . . . . . . . . .  64
     5.12. Security Filtering  . . . . . . . . . . . . . . . . . . .  64



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       5.12.1.  MAC Loop Protection  . . . . . . . . . . . . . . . .  64
       5.12.2.  MAC Address Limit  . . . . . . . . . . . . . . . . .  65
     5.13. Ethernet Service OAM  . . . . . . . . . . . . . . . . . .  65
     5.14. External ID References  . . . . . . . . . . . . . . . . .  66
     5.15. Defining NNIs and Inter-AS support  . . . . . . . . . . .  66
       5.15.1.  Defining an NNI with the Option A Flavor . . . . . .  68
       5.15.2.  Defining an NNI with the Option B Flavor . . . . . .  71
       5.15.3.  Defining an NNI with the Option C Flavor . . . . . .  73
     5.16. Inter-Provider support with EVC and OVC or NNI  . . . . .  75
   6.  Interaction with Other YANG Modules . . . . . . . . . . . . .  76
   7.  Service Model Usage Example . . . . . . . . . . . . . . . . .  78
   8.  YANG Module . . . . . . . . . . . . . . . . . . . . . . . . .  83
   9.  Security Considerations . . . . . . . . . . . . . . . . . . . 155
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 155
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 155
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . . 156
     12.1.  Normative References . . . . . . . . . . . . . . . . . . 156
     12.2.  Informative References . . . . . . . . . . . . . . . . . 157
   Appendix A.  Changes Log  . . . . . . . . . . . . . . . . . . . . 158
   Appendix B.  Open Issues  . . . . . . . . . . . . . . . . . . . . 160
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 160

1.  Introduction

   This document defines a YANG data model for Layer 2 VPN (L2VPN)
   service configuration.  This model is intended to be instantiated at
   management system to allow a user (a customer or an application) to
   request the service from a service provider.  This model is not a
   configuration model to be used directly on network elements, but
   provides an abstracted view of the L2VPN service configuration
   components.  It is up to a management system to take this as an input
   and generate specific configurations models to configure the
   different network elements to deliver the service.  How configuration
   of network elements is done is out of scope of the document.

   The data model in this document includes support for point-to-point
   Virtual Private Wire Services (VPWS) and multipoint Virtual Private
   LAN services (VPLS) that use Pseudowires signaled using the Label
   Distribution Protocol (LDP) and the Border Gateway Protocol (BGP) as
   described in [RFC4761] and [RFC6624].

   Further discussion of the way that services are modeled in YANG and
   of the relationship between "customer service models" like the one
   described in this document and configuration models can be found in
   [I-D.ietf-opsawg-service-model-explained].  Section 4 and Section 6
   also provide more information of how this service model could be used
   and how it fits into the overall modeling architecture.




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1.1.  Terminology

   The following terms are defined in [RFC6241] and are not redefined
   here:

   o  client

   o  configuration data

   o  server

   o  state data

   The following terms are defined in [RFC6020] and are not redefined
   here:

   o  augment

   o  data model

   o  data node

   The terminology for describing YANG data models is found in
   [RFC6020].

1.2.  Tree diagram

   A simplified graphical representation of the data model is presented
   in Section 5.

   The meaning of the symbols in these diagrams is as follows:

   o  Brackets "[" and "]" enclose list keys.

   o  Curly braces "{" and "}" contain names of optional features that
      make the corresponding node conditional.

   o  Abbreviations before data node names: "rw" means configuration
      (read-write), and "ro" state data (read-only).

   o  Symbols after data node names: "?" means an optional node and "*"
      denotes a "list" or "leaf-list".

   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.



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2.  Definitions

   This document uses the following terms:

   Service Provider (SP):  The organization (usually a commercial
      undertaking) responsible for operating the network that offers VPN
      services to clients and customers.

   Customer Edge (CE) Device:  Equipment that is dedicated to a
      particular customer and is directly connected to one or more PE
      devices via attachment circuits.  A CE is usually located at the
      customer premises, and is usually dedicated to a single VPN,
      although it may support multiple VPNs if each one has separate
      attachment circuits.  The CE devices can be routers, bridges,
      switches, or hosts.

   Provider Edge (PE) Device:  Equipment managed by the SP that can
      support multiple VPNs for different customers, and is directly
      connected to one or more CE devices via attachment circuits.  A PE
      is usually located at an SP point of presence (PoP) and is managed
      by the SP.

   Virtual Private LAN Service (VPLS):  A VPLS is a provider service
      that emulates the full functionality of a traditional Local Area
      Network (LAN).  A VPLS makes it possible to interconnect several
      LAN segments over a packet switched network (PSN) and makes the
      remote LAN segments behave as one single LAN.

   Virtual Private Wire Service (VPWS):  A VPWS is a point-to-point
      circuit (i.e., link) connecting two CE devices.  The link is
      established as a logical through a packet switched network.  The
      CE in the customer network is connected to a PE in the provider
      network via an Attachment Circuit (AC): the AC is either a
      physical or a logical circuit.  A VPWS differs from a VPLS in that
      the VPLS is point-to-multipoint, while the VPWS is point-to-point.
      In some implementations, a set of VPWSs is used to create a multi-
      site L2VPN network.

   Pseudowire(PW):  A pseudowire is an emulation of a native service
      over a packet switched network (PSN).  The native service may be
      ATM, frame relay, Ethernet, low-rate TDM, or SONET/SDH, while the
      PSN may be MPLS, IP (either IPv4 or IPv6), or L2TPv3.

   Ethernet Virtual Connection(EVC):  An EVC is an association of two or
      more UNIs that limits the exchange of Service Frames to UNIs in
      the Ethernet Virtual Connection (EVC).





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   Operator Virtual Connection(OVC):   An OVC is the association of UNIs
      and ENNIs or two ENNIs within one administrative domain.

   This document uses the following abbreviations:

   BSS:  Business Support System

   B-U-M:  Broadcast-UnknownUnicast-Multicast

   CoS:  Class of Service

   LAG:  Link Aggregation Group

   LLDP:  Link Level Discovery Protocol

   OAM:  Operations, Administration, and Maintenance

   OSS:  Operations Support System

   PDU:  Protocol Data Unit

   QoS:  Quality of Service

   UNI:  User to Network Interface

3.  The Layer 2 VPN Service Model

   A Layer 2 VPN service is a collection of sites that are authorized to
   exchange traffic between each other over a shared infrastructure of a
   common technology.  This Layer 2 VPN service model (L2SM) provides a
   common understanding of how the corresponding Layer 2 VPN service is
   to be deployed over the shared infrastructure.

   This document presents the L2SM using the YANG data modeling language
   [RFC6020] as a formal language that is both human-readable and
   parsable by software for use with protocols such as NETCONF [RFC6241]
   and RESTCONF [RFC8040].

   This service model is limited to VPWS and VPLS based VPNs as
   described in [RFC4761] and [RFC6624] and EVPN as described in
   [RFC7432].

3.1.  Applicability of the Layer 2 VPN Service Model

   The L2SM defined in this document applies to VPW Service, VPLS
   service,EVPN service and Ethernet virtual circuit Services(e.g.,
   E-Line and E-LAN service).




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   Over the past decade, The MEF Forum (MEF) has published a series of
   technical specifications of Ethernet virtual circuit service
   attributes and implementation agreements between providers.  Many
   Ethernet VPN service providers worldwide have adopted these MEF
   standards and developed backoffice tools accordingly.  IETF also
   works on extending L2VPN Framework [RFC4664] to support those
   services in the MPLS network.

   Rather than introducing a new set of terminologies, the L2SM will
   align with existing MEF attributes when it's applicable to Ethernet
   Virtual Circuit Service.  Therefore, service providers can easily
   integrate any new application that leverages the L2SM data using(for
   example, a Service Orchestrator), with existing BSS/OSS toolsets.
   Service providers also have the option to generate L2SM data for
   current L2VPN customer circuits already deployed in the network.

3.2.  Layer 2 VPN Service Types

   From technology perspective, a set of basic L2VPN service types
   include:

   o  Point-to-point Virtual Private Wire Services (VPWS);

   o  PWE3 (Pseudo-Wire Emulation Edge to Edge) Services that use LDP-
      signaled Pseudowires;

   o  Multipoint Virtual Private LAN services (VPLS) that use LDP-
      signaled Pseudowires;

   o  Multipoint Virtual Private LAN services (VPLS) that use a Border
      Gateway Protocol (BGP) control plane as described in RFC4761 and
      RFC6624;

   o  Ethernet VPNs specified in RFC 7432;

   o  EVC Service

   An EVC circuit can also be port-based, in which case any service
   frames received from a subscriber within the contractual bandwidth
   will be delivered to the corresponding remote site, regardless of the
   customer VLAN value (C-tag) of the incoming frame.  When multiple
   service frames are received from a subscriber and each service frame
   has different C-tag, all C-tags have to be mapped to one Ethernet
   Service(i.e., All to One bundling).  The service frames can also be
   native Ethernet frames without a C-tag.  In this scenario, only one
   Ethernet Virtual Circuit (EVC) is allowed on a single provider to
   subscriber link.




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   Contrary to the above use case, incoming customer service frames may
   be split into multiple EVCs based on pre-arrangement between the
   service provider and customer.  Typically, C-tag of the incoming
   frames will serve as the service delimiter for EVC multiplexing over
   the same provider to subscriber interconnection.

   Combining the port based attribute and service-multiplexing attribute
   with the connection type (point-to-point or multipoint-to-
   multipoint), an Ethernet Virtual Circuit may fall into one of the
   following service types:

   o  E-Line services: Point-to-Point Layer 2 connections.

      EPL:  In its simplest form, a port-based Ethernet Private Line
         (EPL) service provides a high degree of transparency delivering
         all customer service frames between local and remote UNIs using
         multiple C-tags to one EVC bundling or All-to-One Bundling [MEF
         6.1].  All unicast/broadcast/multicast packets are delivered
         unconditionally over the EVC.  No service multiplexing is
         allowed on an EPL UNI.  Note that The UNI interface connecting
         provider edge and customer edge devices is called an Attachment
         Circuit (AC) and can be a physical or virtual link.

      EVPL:  On the other hand, a VLAN based Ethernet Virtual Private
         Line (EVPL) service supports multiplexing more than one point-
         to-point, or even other virtual private services, on the same
         UNI.  Ingress service frames are conditionally transmitted
         through one of the EVCs based upon pre-agreed C-tag to EVC
         mapping.  EVPL supports multiple C-tags to one EVC bundling.

   o  E-LAN services: Multipoint-to-Multipoint Layer 2 connections.

      EP-LAN:  An Ethernet Private LAN Service (EP-LAN) transparently
         connects multiple subscriber sites together with All-to-One
         Bundling.  No service multiplexing is allowed on an EP-LAN UNI.

      EVP-LAN:  Some subscribers may desire more sophisticated control
         of data access between multiple sites.  An Ethernet Virtual
         Private LAN Service (EVP-LAN) allows multiple EVCs to be
         connected to from one or more of the UNIs.  Services frame
         disposition is based on C-tag to EVC mapping.  EVP-LAN supports
         multiple C-tags bundled to one EVC.

3.3.  Layer 2 VPN Physical Network Topology

   Figure 1 depicts a typical service provider's physical network
   topology.  Most service providers have deployed an IP, MPLS, or
   Segment Routing (SR) multi-service core infrastructure.  A L2VPN



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   provides end-to-end L2 connectivity over this multi-service core
   infrastructure between two or more locations of Customers or a
   collection of sites.  Attachment Circuit are placed between CE
   devices and PE Devices that backhaul service frames from the customer
   over the access network to the Provider Network or remote Site.  The
   demarcation point (i.e.,UNI) between customer and service provider
   can be either placed between C and Customer Edge Device or between
   Customer Edge Device and Provider Edge Device.  The actual bearer,
   connection, network access type between CE and PE will be discussed
   in the L2SM model.

                Site A                              Site B
       ---     ----                                                ---
      |   |   |    |                                              |   |
      | C +---+ CE |                                              | C |
      |   |   |    |              ---------                       |   |
       ---     ----\             (         )                      /---
                    \  ----     (           )     ----     ----  /
                     \|    |   (             )   |    |   |    |/
                      | PE +---+ IP/MPLS/SR  +---+ PE +---+ CE |
                     /|    |   (  Network    )   |    |   |    |\
                    /  ----     (           )     ----     ----  \
       ---     ----/             (         )                      \---
      |   |   |    |              ----+----                       |   |
      | C +---+ CE |                  |                           | C |
      |   |   |    |                --+--                         |   |
       ---     ----                | PE  |                         ---
                                    --+--
                                     |      Site C
                                    --+--
                                   | CE  |
                                    --+--
                                      |
                                    --+--
                                   |  C  |
                                    -----

    Figure 1: Reference Network for the Use of the L2VPN Service Model

   From the customer perspective, however, all the customer edge devices
   are connected over a simulated LAN environment as shown in Figure 2.
   Broadcast and multicast packets are sent to all participants in the
   same bridge domain.








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                        CE---+----+---+---CE
                             |    |     |
                             |    |     |
                             |    |     |
                        CE---+    CE    +---CE

                   Figure 2: Customer View of the L2VPN

3.4.  Layer 2 VPN Ethernet Virtual Circuit Construct

   The base model of L2VPN EVC is shown in Figure 3.

   Customer edge network device (CE) connects to the service provider's
   PE equipment.  The demarcation point between customer and service
   provider devices is referred as the User Network Interface (UNI).
   The UNI interface connecting PE and CE devices can be a physical or
   virtual port.  For clarification, this is called the UNI-C on the
   customer side and UNI-N on the provider side.

   The service provider is obligated to deliver the original service
   frame from local UNI-C across the network to the remote UNI-C.  All
   Ethernet and IP header information, include (but not limit to) source
   and destination MAC addresses, EtherType, VLAN (C-tag), Class-of-
   Service marking (802.1p or DSCP), etc.

   Incoming service frames are first examined at UNI-C based on C-tag,
   Class-of-Services identifier, EtherType value.  Conforming packets
   are then metered against the contractual service bandwidth.
   Conforming packets will be delivered to the remote UNI via the
   Ethernet Virtual Circuit (EVC), which spans between UNI-C and UNI-C.

   When both CEs are located in the same provider's network, a single
   operator maintains the EVC.  In this case, the EVC consists of only
   one Operator Virtual Circuit (OVC).

   Typically, the CE device at customer premises is a layer 2 Ethernet
   switch.  A service provider may choose to impose an outer VLAN tag
   (S-tag) into the received subscriber traffic following 802.1ad Q-in-Q
   standard, especially when Layer 2 aggregation devices exist between
   CE and PE.

   The uplink from PE to PE is referred as an Internal Network-to-
   Network Interface (I-NNI).  When 802.1ad Q-in-Q is implemented,
   Ethernet frames from CE to PE are double tagged with both provider
   and subscriber VLANs (S-tag, C-tag).

   Most service providers have deployed MPLS or SR multi-service core
   infrastructure.  Ingress service frames will be mapped to either



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   Ethernet Pseudowire (PWE) or VxLAN tunnel PE-to-PE.  The details of
   these tunneling mechanism are at the provider's discretion and not
   part of the L2SM.

   The service provider may also choose a Seamless MPLS approach to
   expand the PWE or VxLAN tunnel between UNI-N to UNI-N.

   The service provider may leverage multi-protocol BGP to auto-discover
   and signal the PWE or VxLAN tunnel end points.

                                   EVC
                  :<---------------------------------->:
                  :                                    :
                  :                                    :
                  :           OVC (Optional)           :
                  :<---------------------------------->:
                  :                                    :
                  :                                    :
                  :             PW / VXLAN             :
                  :   :<-------------------------->:   :
                  :   :                            :   :
                  :   :                            :   :
                  :   :          --------          :   :
                  :   :         (        )         :   :
     ---     ----     ----     (          )     ----     ----     ---
    |   |   |    |   |    |   (            )   |    |   |    |   |   |
    | C +---+ CE +---+ PE +---+ IP/MPLS/SR +---+ PE +---+ CE +---+ C |
    |   |   |    |   |    |   (  Network   )   |    |   |    |   |   |
     ---     ----     ----     (          )     ----     ----     ---
      ^      ^        :         (        )         :        :
      :      :        :          --------          :        :
            UNI-C   UNI-N                          :        :
             :        :                            :        :
     :<----->:<------>:<-------------------------->:<------>:<---->:
      802.3  802.1Q      IP/MPLS/SR Domain          802.1Q  802.3
              q-in-q                                q-in-q

        Figure 3: Architectural Model for EVC over a Single Network

   Nevertheless, the remote site may be outside of the provider's
   service territory.  In this case, the provider may partner with the
   operator of another metro network to provide service to the off-net
   location as shown in Figure 4.

   The first provider owns the customer relationship, thus the end-to-
   end EVC.  The EVC is comprised of two or more OVCs.  The EVC is
   partially composed of an OVC from local UNI-C to the inter- provider




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   interface.  The provider will purchase an Ethernet Access (E-Access)
   OVC from the second operator to deliver packet to the remote UNI-C.

   The inter-connect between the two operators edge gateway (EG) devices
   is defined as the External Network-to-Network Interface (E-NNI).

                            EVC
           :<----------------------------------------------->:
           :                                                 :
           :                                                 :
           :     OVC (Optional)                              :
           :<--------------------->:                         :
           :                       :                         :
           :                       :                         :
           :         PW / VXLAN    :                         :
           :  :<------------------>:                         :
           :  :                    :                         :
           :  :                    :                         :
           :  :      -----         :            -----        :
           :  :     (     )        :           (     )       :
     -   --   --   (  IP/  )   ----    ----   (  IP/  )   --   --   -
    |C+-+CE+-+PE+--+ MPLS/ +--+Edge+--+Edge+--+ MPLS/ +--+PE+-+CE+-+C|
     -   --   --   (  SR   )  |G/W |  |G/W |  (  SR   )   --   --   -
     ^    ^   :     (     )    ----    ----    (     )              ^
     :    :   :      -----         ^   ^        -----               :
      UNI-C UNI-N
     :                                 ENNI                 :
     :                               :                      :
          :   :                      :                      Remote
    :<--->:<->:<------------------>: <->:                   Customer
    802.3 802.1Q    IP/MPLS/SR      802.1ah                    Site
           q-in-q      Domain       q-in-q

       Figure 4: Architectural Model for EVC over Multiple Networks

4.  Service Data Model Usage

   The L2VPN service model provides an abstracted interface to request,
   configure, and manage the components of a L2VPN service.  The model
   is used by a customer who purchases connectivity and other services
   from an SP to communicate with that SP.

   A typical usage for this model is to be an input to an orchestration
   layer that is responsible for translating it into configuration
   commands for the network elements that deliver/enable the service.
   The network elements may be routers, but also servers (like AAA) that
   are necessary within the network.




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   The configuration of network elements may be done using the Command
   Line Interface (CLI), or any other configuration (or "southbound")
   interface such as NETCONF [RFC6241] in combination with device-
   specific and protocol-specific YANG models.

   This way of using the service model is illustrated in Figure 5 and
   described in more detail in
   [I-D.ietf-opsawg-service-model-explained].  The usage of this service
   model is not limited to this example: it can be used by any component
   of the management system, but not directly by network elements.

   The usage and structure of this model should be compared to the Layer
   3 VPN service model defined in [RFC8049].


          ----------------------------
         | Customer Service Requester |
          ----------------------------
              |
      L2VPN   |
      Service |
      Model   |
              |
            -----------------------
           | Service Orchestration |
            -----------------------
              |
              |     Service             +-------------+
              |     Delivery    +------>| Application |
              |     Model       |       |   BSS/OSS   |
              |                 V       +-------------+
            -----------------------
           | Network Orchestration |
            -----------------------
              |            |
      +----------------+   |
      | Config manager |   |
      +----------------+   |  Device
              |            |  Models
              |            |
   --------------------------------------------
                     Network


     Figure 5: Reference Architecture for the Use of the L2VPN Service
                                   Model





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   Additionally, this data model can be compared with the service
   delivery models described in [I-D.ietf-bess-l2vpn-yang] and
   [I-D.ietf-bess-evpn-yang] as discussed in Section 6.

5.  Design of the Data Model

   The L2SM model is structured in a way that allows the provider to
   list multiple circuits of various service types for the same
   subscriber.

   The YANG module is divided in two main containers: vpn-services, and
   sites.  The vpn-svc container under vpn-services defines global
   parameters for the VPN service for a specific customer.

   A site contains at least one network access (i.e., site network
   accesses providing access to the sites defined in Section 5.3.3) and
   there may be multiple ports in case of multihoming.  The site to
   network access attachment is done through a bearer with a Layer 2
   connection on top.  The bearer refers to properties of the attachment
   that are below layer 2 while the connection refers to layer 2
   protocol oriented properties.  The bearer may be allocated
   dynamically by the service provider and the customer may provide some
   constraints or parameters to drive the placement.

   Authorization of traffic exchange is done through what we call a VPN
   policy or VPN topology defining routing exchange rules between sites.

   The figure below describe the overall structure of the YANG module:

module: ietf-l2vpn-svc
   +--rw l2vpn-svc
      +--rw vpn-services
      |  +--rw vpn-svc* [vpn-id]
      |     +--rw vpn-id                     svc-id
      |     +--rw vpn-type?                  identityref
      |     +--rw customer-account-number?   uint32
      |     +--rw customer-name?             string
      |     +--rw evc
      |     |  +--rw enabled?                    boolean
      |     |  +--rw evc-type?                   identityref
      |     |  +--ro number-of-pe?               uint32
      |     |  +--ro number-of-site?             uint32
      |     |  +--rw uni-list {uni-list}?
      |     |  |  +--rw uni-list* [uni-site-id]
      |     |  |     +--rw uni-site-id    string
      |     |  |     +--rw off-net?       boolean
      |     |  +--rw ce-vlan-preservation?       boolean
      |     |  +--rw ce-vlan-cos-perservation?   boolean



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      |     |  +--rw service-multiplexing?       boolean
      |     +--rw ovc {ovc-type}?
      |     |  +--rw ovc-list* [ovc-id]
      |     |     +--rw ovc-id                    svc-id
      |     |     +--rw off-net?                  boolean
      |     |     +--rw svlan-cos-preservation?   boolean
      |     |     +--rw svlan-id-preservation?    boolean
      |     |     +--rw svlan-id-ethernet-tag?    string
      |     |     +--rw ovc-endpoint?             string
      |     +--rw svc-topo?                  identityref
      |     +--rw cloud-accesses {cloud-access}?
      |     |  +--rw cloud-access* [cloud-identifier]
      |     |     +--rw cloud-identifier    string
      |     |     +--rw (list-flavor)?
      |     |        +--:(permit-any)
      |     |        |  +--rw permit-any?         empty
      |     |        +--:(deny-any-except)
      |     |        |  +--rw permit-site*        -> /l2vpn-svc/sites/site/site-id
      |     |        +--:(permit-any-except)
      |     |           +--rw deny-site*          -> /l2vpn-svc/sites/site/site-id
      |     +--rw metro-network-id
      |     |  +--rw inter-mkt-service?   boolean
      |     |  +--rw intra-mkt* [metro-mkt-id mkt-name]
      |     |     +--rw metro-mkt-id    uint32
      |     |     +--rw mkt-name        string
      |     |     +--rw ovc-id?         -> /l2vpn-svc/vpn-services/vpn-svc/ovc/ovc-list/ovc-id
      |     |     +--rw site-id?        -> /l2vpn-svc/sites/site/site-id
      |     +--rw global-l2cp-control {L2CP-control}?
      |     |  +--rw stp-rstp-mstp?   control-mode
      |     |  +--rw pause?           control-mode
      |     |  +--rw lldp?            boolean
      |     +--rw load-balance-options
      |     |  +--rw fat-pw?              boolean
      |     |  +--rw entropy-label?       boolean
      |     |  +--rw vxlan-source-port?   string
      |     +--rw service-level-mac-limit?   string
      |     +--rw service-protection
      |     |  +--rw protection-model?   identityref
      |     +--rw cvlan-id-to-svc-map* [svc-id type]
      |     |  +--rw svc-id      -> /l2vpn-svc/vpn-services/vpn-svc/vpn-id
      |     |  +--rw type        identityref
      |     |  +--rw cvlan-id* [vid]
      |     |     +--rw vid    identityref
      |     +--rw multicast {multicast}?
      |     |  +--rw enabled?                 boolean
      |     |  +--rw customer-tree-flavors
      |     |  |  +--rw tree-flavor*   identityref
      |     |  +--rw traffic-type?            identityref



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      |     |  +--rw group-port-mapping?      identityref
      |     +--rw extranet-vpns {extranet-vpn}?
      |        +--rw extranet-vpn* [vpn-id]
      |           +--rw vpn-id              svc-id
      |           +--rw local-sites-role?   identityref
      +--rw sites
         +--rw site* [site-id site-type]
            +--rw site-id                                string
            +--rw site-type                              identityref
            +--rw device
            |  +--rw devices* [device-id]
            |     +--rw device-id     string
            |     +--rw location?     -> /l2vpn-svc/sites/site/locations/location/location-id
            |     +--rw management
            |        +--rw address?                inet:ip-address
            |        +--rw management-transport?   identityref
            +--rw locations
            |  +--rw location* [location-id]
            |     +--rw location-id     string
            |     +--rw address?        string
            |     +--rw zip-code?       string
            |     +--rw state?          string
            |     +--rw city?           string
            |     +--rw country-code?   string
            +--rw management
            |  +--rw type?   identityref
            +--rw site-diversity {site-diversity}?
            |  +--rw groups
            |     +--rw group* [group-id]
            |        +--rw group-id    string
            +--rw vpn-policies
            |  +--rw vpn-policy* [vpn-policy-id]
            |     +--rw vpn-policy-id    string
            |     +--rw entries* [id]
            |        +--rw id        string
            |        +--rw filter
            |        |  +--rw (lan)?
            |        |     +--:(lan-tag)
            |        |        +--rw lan-tag*   string
            |        +--rw vpn
            |           +--rw vpn-id       -> /l2vpn-svc/vpn-services/vpn-svc/vpn-id
            |           +--rw site-role?   identityref
            +--rw signaling-options {signaling-options}?
            |  +--rw signaling-options* [type]
            |     +--rw type           identityref
            |     +--rw bgp-l2vpn
            |     |  +--rw vpn-id?           -> /l2vpn-svc/vpn-services/vpn-svc/vpn-id
            |     |  +--rw type?             identityref



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            |     |  +--rw address-family?   identityref
            |     +--rw mp-bgp-evpn
            |     |  +--rw vpn-id?                   -> /l2vpn-svc/vpn-services/vpn-svc/vpn-id
            |     |  +--rw type?                     identityref
            |     |  +--rw address-family?           identityref
            |     |  +--rw pwe-encapsulation-type?   identityref
            |     |  +--rw pwe-mtu
            |     |  |  +--rw allow-mtu-mismatch?   boolean
            |     |  +--rw mac-learning-mode?        identityref
            |     |  +--rw arp-suppress?             boolean
            |     +--rw t-ldp-pwe
            |     |  +--rw type?           identityref
            |     |  +--rw pe-eg-list* [service-ip-addr vc-id]
            |     |  |  +--rw service-ip-addr    inet:ip-address
            |     |  |  +--rw vc-id              string
            |     |  +--rw control-word?   boolean
            |     |  +--rw qinq
            |     |     +--rw s-tag?   uint32
            |     |     +--rw c-tag?   uint32
            |     +--rw l2tp-pw
            |        +--rw encapsulation-type?   identityref
            |        +--rw control-word
            +--rw load-balance-options
            |  +--rw fat-pw?              boolean
            |  +--rw entropy-label?       boolean
            |  +--rw vxlan-source-port?   string
            +--rw service
            |  +--rw qos {qos}?
            |     +--rw qos-classification-policy
            |     |  +--rw rule* [id]
            |     |     +--rw id                 uint16
            |     |     +--rw (match-type)?
            |     |     |  +--:(match-flow)
            |     |     |  |  +--rw match-flow
            |     |     |  |     +--rw dscp?           inet:dscp
            |     |     |  |     +--rw dot1p?          uint8
            |     |     |  |     +--rw pcp?            uint8
            |     |     |  |     +--rw src-mac?        yang:mac-address
            |     |     |  |     +--rw dst-mac?        yang:mac-address
            |     |     |  |     +--rw composite-id
            |     |     |  |     |  +--rw endpoint-id?   string
            |     |     |  |     |  +--rw cos-label?     identityref
            |     |     |  |     |  +--rw pcp?           uint8
            |     |     |  |     |  +--rw dscp?          inet:dscp
            |     |     |  |     +--rw color-type?     identityref
            |     |     |  |     +--rw target-sites*   svc-id
            |     |     |  +--:(match-phy-port)
            |     |     |     +--rw match-phy-port?    uint16



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            |     |     +--rw target-class-id?   string
            |     +--rw qos-profile
            |        +--rw (qos-profile)?
            |           +--:(standard)
            |           |  +--rw ingress-profile?   string
            |           |  +--rw egress-profile?    string
            |           +--:(custom)
            |              +--rw classes {qos-custom}?
            |                 +--rw class* [class-id]
            |                    +--rw class-id              string
            |                    +--rw direction?            direction-type
            |                    +--rw policing?             identityref
            |                    +--rw byte-offset?          uint16
            |                    +--rw rate-limit?           uint8
            |                    +--rw discard-percentage?   uint8
            |                    +--rw frame-delay
            |                    |  +--rw (flavor)?
            |                    |     +--:(lowest)
            |                    |     |  +--rw use-low-del?   empty
            |                    |     +--:(boundary)
            |                    |        +--rw delay-bound?   uint16
            |                    +--rw frame-jitter
            |                    |  +--rw (flavor)?
            |                    |     +--:(lowest)
            |                    |     |  +--rw use-low-jit?   empty
            |                    |     +--:(boundary)
            |                    |        +--rw delay-bound?   uint32
            |                    +--rw frame-loss
            |                    |  +--rw fr-loss-rate?   decimal64
            |                    +--rw bandwidth
            |                       +--rw guaranteed-bw-percent?   uint8
            |                       +--rw end-to-end?              empty
            +--rw broadcast-unknown-unicast-multicast
            |  +--rw multicast-site-type?            enumeration
            |  +--rw multicast-gp-address-mapping* [id]
            |  |  +--rw id                 uint16
            |  |  +--rw vlan-id?           uint32
            |  |  +--rw mac-gp-address?    yang:mac-address
            |  |  +--rw port-lag-number?   uint32
            |  +--rw bum-overall-rate?               uint32
            |  +--rw bum-rate-per-type* [type]
            |     +--rw type    identityref
            |     +--rw rate?   uint32
            +--rw security-filtering
            |  +--rw mac-loop-prevention
            |  |  +--rw frequency?         uint32
            |  |  +--rw protection-type?   identityref
            |  |  +--rw number-retries?    uint32



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            |  +--rw access-control-list
            |  |  +--rw mac* [mac-address]
            |  |     +--rw mac-address    yang:mac-address
            |  +--rw mac-addr-limit
            |     +--rw exceeding-option?   uint32
            +--ro actual-site-start?                     yang:date-and-time
            +--ro actual-site-stop?                      yang:date-and-time
            +--rw site-network-accesses
               +--rw site-network-accesse* [network-access-id]
                  +--rw network-access-id                      string
                  +--rw remote-carrier-name?                   string
                  +--rw access-diversity {site-diversity}?
                  |  +--rw groups
                  |  |  +--rw fate-sharing-group-size?   uint16
                  |  |  +--rw group* [group-id]
                  |  |     +--rw group-id    string
                  |  +--rw constraints
                  |     +--rw constraint* [constraint-type]
                  |        +--rw constraint-type    identityref
                  |        +--rw target
                  |           +--rw (target-flavor)?
                  |              +--:(id)
                  |              |  +--rw group* [group-id]
                  |              |     +--rw group-id    string
                  |              +--:(all-accesses)
                  |              |  +--rw all-other-accesses?   empty
                  |              +--:(all-groups)
                  |                 +--rw all-other-groups?     empty
                  +--rw bearer
                  |  +--rw requested-type {requested-type}?
                  |  |  +--rw requested-type?         string
                  |  |  +--rw strict?                 boolean
                  |  |  +--rw request-type-profile
                  |  |     +--rw (request-type-choice)?
                  |  |        +--:(dot1q-case)
                  |  |        |  +--rw dot1q
                  |  |        |     +--rw physical-if?   string
                  |  |        |     +--rw vlan-id?       uint16
                  |  |        +--:(physical-case)
                  |  |           +--rw physical-if?   string
                  |  |           +--rw circuit-id?    string
                  |  +--rw always-on?          boolean {always-on}?
                  |  +--rw bearer-reference?   string {bearer-reference}?
                  +--rw connection
                  |  +--rw encapsulation-type
                  |  |  +--rw encapsulation-type?   identityref
                  |  |  +--rw eth-type?             identityref
                  |  +--rw esi?                     string



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                  |  +--rw interface-description?   string
                  |  +--rw sub-if-id?               uint32
                  |  +--rw vlan {vlan}?
                  |  |  +--rw vlan-id?   uint32
                  |  +--rw dot1q {dot1q}?
                  |  |  +--rw physical-inf?   string
                  |  |  +--rw c-vlan-id?      uint32
                  |  +--rw qinq {qinq}?
                  |  |  +--rw s-vlan-id?   uint32
                  |  |  +--rw c-vlan-id?   uint32
                  |  +--rw qinany {qinany}?
                  |  |  +--rw s-vlan-id?   uint32
                  |  +--rw vxlan {vxlan}?
                  |  |  +--rw vni-id?      uint32
                  |  |  +--rw peer-list* [peer-ip]
                  |  |     +--rw peer-ip    inet:ip-address
                  |  +--rw phy-interface
                  |  |  +--rw port-number?           uint32
                  |  |  +--rw port-speed?            uint32
                  |  |  +--rw mode?                  neg-mode
                  |  |  +--rw phy-mtu?               uint32
                  |  |  +--rw flow-control?          string
                  |  |  +--rw encapsulation-type?    identityref
                  |  |  +--rw ethertype?             identityref
                  |  |  +--rw lldp?                  boolean
                  |  |  +--rw oam-802.3ah-link {oam-3ah}?
                  |  |  |  +--rw enable?   boolean
                  |  |  +--rw uni-loop-prevention?   boolean
                  |  +--rw lag-interface {lag-interface}?
                  |  |  +--rw lag-interface* [lag-interface-number]
                  |  |     +--rw lag-interface-number    uint32
                  |  |     +--rw lacp
                  |  |        +--rw lacp-state?           boolean
                  |  |        +--rw lacp-mode?            boolean
                  |  |        +--rw lacp-speed?           boolean
                  |  |        +--rw mini-link?            uint32
                  |  |        +--rw system-priority?      uint16
                  |  |        +--rw micro-bfd {micro-bfd}?
                  |  |        |  +--rw micro-bfd-on-off?   enumeration
                  |  |        |  +--rw bfd-interval?       uint32
                  |  |        |  +--rw bfd-hold-timer?     uint32
                  |  |        +--rw bfd {bfd}?
                  |  |        |  +--rw bfd-enabled?    boolean
                  |  |        |  +--rw (holdtime)?
                  |  |        |     +--:(profile)
                  |  |        |     |  +--rw profile-name?   string
                  |  |        |     +--:(fixed)
                  |  |        |        +--rw fixed-value?    uint32



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                  |  |        +--rw member-link-list
                  |  |        |  +--rw member-link* [name]
                  |  |        |     +--rw name                string
                  |  |        |     +--rw port-speed?         uint32
                  |  |        |     +--rw mode?               neg-mode
                  |  |        |     +--rw mtu?                uint32
                  |  |        |     +--rw oam-802.3ah-link {oam-3ah}?
                  |  |        |        +--rw enable?   boolean
                  |  |        +--rw flow-control?         string
                  |  |        +--rw encapsulation-type?   identityref
                  |  |        +--rw ethertype?            identityref
                  |  |        +--rw lldp?                 boolean
                  |  +--rw l2cp-control {L2CP-control}?
                  |     +--rw stp-rstp-mstp?           control-mode
                  |     +--rw pause?                   control-mode
                  |     +--rw lacp-lamp?               control-mode
                  |     +--rw link-oam?                control-mode
                  |     +--rw esmc?                    control-mode
                  |     +--rw l2cp-802.1x?             control-mode
                  |     +--rw e-lmi?                   control-mode
                  |     +--rw lldp?                    boolean
                  |     +--rw ptp-peer-delay?          control-mode
                  |     +--rw garp-mrp?                control-mode
                  |     +--rw provider-bridge-group?   control-mode
                  |     +--rw provider-bridge-mvrp?    control-mode
                  +--rw svc-mtu?                               uint32
                  +--rw availability
                  |  +--rw access-priority?   uint32
                  |  +--rw (redundancy-mode)?
                  |     +--:(single-active)
                  |     |  +--rw single-active?     boolean
                  |     +--:(all-active)
                  |        +--rw all-active?        boolean
                  +--rw vpn-attachment
                  |  +--rw device-id?       string
                  |  +--rw management
                  |  |  +--rw address-family?   identityref
                  |  |  +--rw address?          inet:ip-address
                  |  +--rw (attachment-flavor)
                  |     +--:(vpn-flavor)
                  |     |  +--rw vpn-flavor* [vpn-id]
                  |     |     +--rw vpn-id       -> /l2vpn-svc/vpn-services/vpn-svc/vpn-id
                  |     |     +--rw site-role?   identityref
                  |     +--:(vpn-policy-id)
                  |        +--rw vpn-policy-id?   -> /l2vpn-svc/sites/site/vpn-policies/vpn-policy/vpn-policy-id
                  +--rw service
                  |  +--rw svc-input-bandwidth {input-bw}?
                  |  |  +--rw input-bandwidth* [type]



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                  |  |     +--rw type      identityref
                  |  |     +--rw cos-id?   uint8
                  |  |     +--rw vpn-id?   svc-id
                  |  |     +--rw CIR?      uint64
                  |  |     +--rw CBS?      uint64
                  |  |     +--rw EIR?      uint64
                  |  |     +--rw EBS?      uint64
                  |  |     +--rw CM?       uint8
                  |  +--rw svc-output-bandwidth {output-bw}?
                  |  |  +--rw output-bandwidth* [type]
                  |  |     +--rw type      identityref
                  |  |     +--rw cos-id?   uint8
                  |  |     +--rw vpn-id?   svc-id
                  |  |     +--rw CIR?      uint64
                  |  |     +--rw CBS?      uint64
                  |  |     +--rw EIR?      uint64
                  |  |     +--rw EBS?      uint64
                  |  |     +--rw CM?       uint8
                  |  +--rw qos {qos}?
                  |     +--rw qos-classification-policy
                  |     |  +--rw rule* [id]
                  |     |     +--rw id                 uint16
                  |     |     +--rw (match-type)?
                  |     |     |  +--:(match-flow)
                  |     |     |  |  +--rw match-flow
                  |     |     |  |     +--rw dscp?           inet:dscp
                  |     |     |  |     +--rw dot1p?          uint8
                  |     |     |  |     +--rw pcp?            uint8
                  |     |     |  |     +--rw src-mac?        yang:mac-address
                  |     |     |  |     +--rw dst-mac?        yang:mac-address
                  |     |     |  |     +--rw composite-id
                  |     |     |  |     |  +--rw endpoint-id?   string
                  |     |     |  |     |  +--rw cos-label?     identityref
                  |     |     |  |     |  +--rw pcp?           uint8
                  |     |     |  |     |  +--rw dscp?          inet:dscp
                  |     |     |  |     +--rw color-type?     identityref
                  |     |     |  |     +--rw target-sites*   svc-id
                  |     |     |  +--:(match-phy-port)
                  |     |     |     +--rw match-phy-port?    uint16
                  |     |     +--rw target-class-id?   string
                  |     +--rw qos-profile
                  |        +--rw (qos-profile)?
                  |           +--:(standard)
                  |           |  +--rw ingress-profile?   string
                  |           |  +--rw egress-profile?    string
                  |           +--:(custom)
                  |              +--rw classes {qos-custom}?
                  |                 +--rw class* [class-id]



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                  |                    +--rw class-id              string
                  |                    +--rw direction?            direction-type
                  |                    +--rw policing?             identityref
                  |                    +--rw byte-offset?          uint16
                  |                    +--rw rate-limit?           uint8
                  |                    +--rw discard-percentage?   uint8
                  |                    +--rw frame-delay
                  |                    |  +--rw (flavor)?
                  |                    |     +--:(lowest)
                  |                    |     |  +--rw use-low-del?   empty
                  |                    |     +--:(boundary)
                  |                    |        +--rw delay-bound?   uint16
                  |                    +--rw frame-jitter
                  |                    |  +--rw (flavor)?
                  |                    |     +--:(lowest)
                  |                    |     |  +--rw use-low-jit?   empty
                  |                    |     +--:(boundary)
                  |                    |        +--rw delay-bound?   uint32
                  |                    +--rw frame-loss
                  |                    |  +--rw fr-loss-rate?   decimal64
                  |                    +--rw bandwidth
                  |                       +--rw guaranteed-bw-percent?   uint8
                  |                       +--rw end-to-end?              empty
                  +--rw broadcast-unknown-unicast-multicast
                  |  +--rw multicast-site-type?            enumeration
                  |  +--rw multicast-gp-address-mapping* [id]
                  |  |  +--rw id                 uint16
                  |  |  +--rw vlan-id?           uint32
                  |  |  +--rw mac-gp-address?    yang:mac-address
                  |  |  +--rw port-lag-number?   uint32
                  |  +--rw bum-overall-rate?               uint32
                  |  +--rw bum-rate-per-type* [type]
                  |     +--rw type    identityref
                  |     +--rw rate?   uint32
                  +--rw ethernet-service-oam
                  |  +--rw md-name?        string
                  |  +--rw md-level?       uint8
                  |  +--rw cfm-802.1-ag
                  |  |  +--rw n2-uni-c* [maid]
                  |  |  |  +--rw maid                     string
                  |  |  |  +--rw mep-id?                  uint32
                  |  |  |  +--rw mep-level?               uint32
                  |  |  |  +--rw mep-up-down?             enumeration
                  |  |  |  +--rw remote-mep-id?           uint32
                  |  |  |  +--rw cos-for-cfm-pdus?        uint32
                  |  |  |  +--rw ccm-interval?            uint32
                  |  |  |  +--rw ccm-holdtime?            uint32
                  |  |  |  +--rw alarm-priority-defect?   identityref



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                  |  |  |  +--rw ccm-p-bits-pri?          ccm-priority-type
                  |  |  +--rw n2-uni-n* [maid]
                  |  |     +--rw maid                     string
                  |  |     +--rw mep-id?                  uint32
                  |  |     +--rw mep-level?               uint32
                  |  |     +--rw mep-up-down?             enumeration
                  |  |     +--rw remote-mep-id?           uint32
                  |  |     +--rw cos-for-cfm-pdus?        uint32
                  |  |     +--rw ccm-interval?            uint32
                  |  |     +--rw ccm-holdtime?            uint32
                  |  |     +--rw alarm-priority-defect?   identityref
                  |  |     +--rw ccm-p-bits-pri?          ccm-priority-type
                  |  +--rw y-1731* [maid]
                  |     +--rw maid                           string
                  |     +--rw mep-id?                        uint32
                  |     +--rw type?                          identityref
                  |     +--rw remote-mep-id?                 uint32
                  |     +--rw message-period?                uint32
                  |     +--rw measurement-interval?          uint32
                  |     +--rw cos?                           uint32
                  |     +--rw loss-measurement?              boolean
                  |     +--rw synthethic-loss-measurement?   boolean
                  |     +--rw delay-measurement
                  |     |  +--rw enable-dm?   boolean
                  |     |  +--rw two-way?     boolean
                  |     +--rw frame-size?                    uint32
                  |     +--rw session-type?                  enumeration
                  +--rw security-filtering
                     +--rw mac-loop-prevention
                     |  +--rw frequency?         uint32
                     |  +--rw protection-type?   identityref
                     |  +--rw number-retries?    uint32
                     +--rw access-control-list
                     |  +--rw mac* [mac-address]
                     |     +--rw mac-address    yang:mac-address
                     +--rw mac-addr-limit
                        +--rw exceeding-option?   uint32

                                 Figure 6

5.1.  Features and Augmentation

   The model defined in this document implements many features that
   allow implementations to be modular.  As an example, the layer 2
   protocols parameters proposed to the customer may also be enabled
   through features.  This model also proposes some features for options
   that are more advanced, such as support for extranet VPNs




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   (Section 5.2.6), site diversity (Section 5.6), and QoS
   (Section 5.10.2).

   In addition, as for any YANG model, this service model can be
   augmented to implement new behaviors or specific features.

5.2.  VPN Service Overview

   A vpn-service list item contains generic informations about the VPN
   service.  The vpn-id of the vpn-service refers to an internal
   reference for this VPN service.  This identifier is purely internal
   to the organization responsible for the VPN service.

   A vpn-service is composed of some characteristics:

   Customer information:  Used to identify the subscriber.

   VPN Type (vpn-type):  Used to indicate VPN service Type.  The
      identifier is a string allowing to any encoding for the local
      administration of the VPN service.

   Ethernet Connection Service Type (evc-type):  used to identify
      supported Ethernet Connection Service Types.

    Cloud Access (cloud-access):  All sites in the L2VPN MUST be
      authorized to access to the cloud.The cloud-access container
      provides parameters for authorization rules.  A cloud identifier
      is used to reference the target service.  This identifier is local
      to each administration.

   Service Topology (svc-topo):  Used to identify the type of VPN
      service topology is required for configuration.

   Metro Network Partition:  Used by service provide to divide the
      network into several administrative domains.

   VPN Signaling (vpn-signaling-option):  Defines which protocol or
      signaling must be activated between the subscriber and the
      provider.

   Load Balance (load-balance-option):  Intended to capture the load-
      balance agreement between the subscriber and provider.

   SVLAN ID Ethernet Tag:  Used to identify the service-wide "normalized
      S-tag".






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   CVLAN ID To EVC MAP:  Contains the list of customer vlans to the
      service mapping in a free-form format.  In most cases, this will
      be the VLAN access-list for the inner 802.1q tags.

   Service Level MAC Limit:  Contains the subscriber MAC address limit
      and exceeding action information.

   Service Protection (svc-protection):  Capture the desired service
      protection agreement between subscriber and provider.

5.2.1.  Customer Information

   The customer information contains two essential information to
   identify the subscriber.

   "customer-account-number" is an internal alphanumerical number
   assigned by the service provider to identify the subscriber.  It MUST
   be unique within the service provider's OSS/BSS system.  The actual
   format depends on the system tool the provider uses. "customer-name"
   is in a more readable form and refers to a more-explicit reference to
   the customer.  Both identifiers are purely internal to the
   organization responsible for the VPN service.

5.2.2.  VPN Service Type

   The "svc-type" defines service type for provider provisioned L2VPNs.
   The current version of the model supports ten flavors:

   o  Point-to-point Virtual Private Wire Services (VPWS);

   o  PWE3 (Pseudo-Wire Emulation Edge to Edge) that use LDP-signaled
      Pseudowires;

   o  Multipoint Virtual Private LAN services (VPLS) that use LDP-
      signaled Pseudowires;

   o  Multipoint Virtual Private LAN services (VPLS) that use a Border
      Gateway Protocol (BGP) control plane as described in RFC4761 and
      RFC6624;

   o  Ethernet VPNs specified in RFC 7432;

   o  Ethernet Private Line (EPL) Service with PW core;

   o  Ethernet Virtual Private Line (EVPL) Service with PW core;

   o  Ethernet Private LAN (EP-LAN)Service with VPLS core;




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   o  Ethernet Virtual Private LAN (EVP-LAN)Service with VPLS core

   Other L2VPN Service Type could be included by augmentation.  Note
   that EPL service and EVPL service are E-Line service or point to
   point EVC service while EP-LAN service and EVP-LAN service are E-LAN
   service or multiple point to multipoint EVC service.

5.2.2.1.  EVC

   The "evc" container contains "enable" leafand "uni-list" container.
   If EVC service for Provider provision L2VPN is required, the
   "enabled" leaf MUST be set to true in the "evc" container. "uni-list"
   will specify the UNI list associated with this EVC service.

   In addition, "evc-type","number of PEs" and "number of sites" can be
   specified under the "evc" container.The "evc-type" defines three EVC
   service types: Point-to-Point,Multipoint-to-Multipoint, Rooted-
   Multipoint.  New Ethernet Connection service types can be added by
   augmentation in the future.

   E-Line and E-LAN providers shall have an EVC-ID assigned to the UNI-
   to-UNI circuit.EVC-ID value will be set to the same VPN-id value
   under vpn-service list.

5.2.2.2.  OVC

   The "ovc-list" under "ovc" container defines a list of "ovc-id"
   parameter associated with "evc" and a "off-net" leaf.  The "off-net"
   leaf MUST be set to true if one of external interface of "ovc" is UNI
   and this UNI can not be reachable by the subscriber or local site.

   For E-Access service as an OVC-based service, the "on-net" leaf MUST
   be marked TRUE, and The E-Access service provider will assign an OVC-
   ID for the circuit between UNI and E-NNI.

   If the service is E-Line or E-LAN with remote UNIs, there will be
   one, and only one, on-net "ovc-id" and a list of off-net "ovc-id"
   objects for the remote UNIs.

5.2.3.  VPN Service Topology

   The type of VPN service topology can be used for configuration if
   needed.  The module currently supports: any-to-any, hub and spoke
   (where hubs can exchange traffic), and hub and spoke disjoint (where
   hubs cannot exchange traffic).  New topologies could be added by
   augmentation.  By default, the any-to-any VPN service topology is
   used.




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5.2.3.1.  Route Target Allocation

   A Layer 2 PE-based VPN (such as VPLS based VPN that uses BGP as
   signaling protocol or EVPN) can be built using route targets (RTs) as
   described in [RFC4364].  The management system is expected to
   automatically allocate a set of RTs upon receiving a VPN service
   creation request.  How the management system allocates RTs is out of
   scope for this document, but multiple ways could be envisaged, as
   described in the section 6.2.1.1 of [RFC8049].

5.2.3.2.  Any-to-Any

        +------------------------------------------------------------+
        |  VPN1_Site1 ------ PE1               PE2 ------ VPN1_Site2 |
        |                                                            |
        |  VPN1_Site3 ------ PE3               PE4 ------ VPN1_Site4 |
        +------------------------------------------------------------+

                      Any-to-Any VPN Service Topology

   In the any-to-any VPN service topology, all VPN sites can communicate
   with each other without any restrictions.  The management system that
   receives an any-to-any L2VPN service request through this model is
   expected to assign and then configure the VFI/VSI/EVI and RTs on the
   appropriate PEs.  In the any-to-any case, a single RT is generally
   required, and every VFI/VSI/EVI imports and exports this RT.

5.2.3.3.  Hub and Spoke

        +-------------------------------------------------------------+
        |   Hub_Site1 ------ PE1               PE2 ------ Spoke_Site1 |
        |                          +----------------------------------+
        |                          |
        |                          +----------------------------------+
        |   Hub_Site2 ------ PE3               PE4 ------ Spoke_Site2 |
        +-------------------------------------------------------------+

                    Hub-and-Spoke VPN Service Topology

   In the Hub-and-Spoke VPN service topology, all Spoke sites can
   communicate only with Hub sites but not with each other, and Hubs can
   also communicate with each other.  The management system that owns an
   any-to-any L2 VPN service request through this model is expected to
   assign and then configure the VFI/VSI/EVI and RTs on the appropriate
   PEs.  In the Hub-and-Spoke case, two RTs are generally required (one
   RT for Hub routes and one RT for Spoke routes).  A Hub VFI/VSI/EVI
   that connects Hub sites will export Hub routes with the Hub RT and
   will import Spoke routes through the Spoke RT.  It will also import



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   the Hub RT to allow Hub-to-Hub communication.  A Spoke VFI/VSI/EVI
   that connects Spoke sites will export Spoke routes with the Spoke RT
   and will import Hub routes through the Hub RT.

5.2.4.  Cloud Access

   This model provides cloud access configuration through the cloud-
   access container.  The usage of cloud-access is targeted for public
   cloud and Internet Access.  The cloud-access container provides
   parameters for authorization rules.

   Private cloud access may be addressed through the site contianer as
   described in Section 5.3 with the use consistent with sites of type
   E-NNI.

   A cloud identifier is used to reference the target service.  This
   identifier is local to each administration.

   By default, all sites in the IP VPN MUST be authorized to access the
   cloud.  If restrictions are required, a user MAY configure the
   "permit-site" or "deny-site" leaf-list.  The permit-site leaf-list
   defines the list of sites authorized for cloud access.  The deny-site
   leaf-list defines the list of sites denied for cloud access.  The
   model supports both "deny-any-except" and "permit-any-except"
   authorization.

   How the restrictions will be configured on network elements is out of
   scope for this document.

                        L2VPN
              ++++++++++++++++++++++++++++++++     ++++++++++++
              +             Site 3           + --- +  Cloud 1 +
              + Site 1                       +     ++++++++++++
              +                              +
              + Site 2                       + --- ++++++++++++
              +                              +     + Internet +
              +            Site 4            +     ++++++++++++
              ++++++++++++++++++++++++++++++++
                           |
                      +++++++++++
                      + Cloud 2 +
                      +++++++++++

   In the example above, we configure the global VPN to access the
   Internet by creating a cloud-access pointing to the cloud identifier
   for the Internet service.  No authorized sites will be configured, as
   all sites are required to access the Internet.




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      <vpn-service>
          <vpn-id>123456487</vpn-id>
          <cloud-accesses>
           <cloud-access>
              <cloud-identifier>INTERNET</cloud-identifier>
           </cloud-access>
          </cloud-accesses>
      </vpn-service>

   If Site 1 and Site 2 require access to Cloud 1, a new cloud-access
   pointing to the cloud identifier of Cloud 1 will be created.  The
   permit-site leaf-list will be filled with a reference to Site 1 and
   Site 2.

      <vpn-service>
          <vpn-id>123456487</vpn-id>
          <cloud-accesses>
           <cloud-access>
              <cloud-identifier>Cloud1</cloud-identifier>
              <permit-site>site1</permit-site>
              <permit-site>site2</permit-site>
           </cloud-access>
          </cloud-accesses>
      </vpn-service>

   If all sites except Site 1 require access to Cloud 2, a new cloud-
   access pointing to the cloud identifier of Cloud 2 will be created.
   The deny-site leaf-list will be filled with a reference to Site 1.

      <vpn-service>
          <vpn-id>123456487</vpn-id>
          <cloud-accesses>
           <cloud-access>
              <cloud-identifier>Cloud2</cloud-identifier>
              <deny-site>site1</deny-site>
           </cloud-access>
          </cloud-accesses>
      </vpn-service>

5.2.5.  Metro Ethernet Network Partition

   Some service providers may divide their Metro Ethernet network into
   multiple administrative domains.  And a EVC service may span across
   multiple such administrative domains belonging to the same service
   provider and be concatenated by one or multiple OVC segments.  Each
   administrative domain has corresponding OVC segment.  The optional
   "metro-networks" container is intended be used by these multi-domain
   providers to differentiate intra-market versus inter-market services.



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   When the "inter-mkt-service" leaf is marked TRUE, multiple associated
   "metro-mkt-id"s will be listed.  Otherwise, the service is intra-
   domain and only one "metro-mkt-id" is allowed.

                 |                                      |
             UNI |            ENNI        ENNI       UNI|
   +-----------+ |  --------  |  --------  |  --------  |+-----------+
   |           | | /        \ | /        \ | /        \ ||           |
   | New York  | || Acccess  |||Transport ||| Service  |||  Paris    |
   |   Site    | || Provider ||| Provider ||| Provider |||   Site    |
   |           | ||  #1      |||  #2      |||  #3      |||           |
   +-----------+ | \        / | \        / | \        / |+-----------+
                 |  --------  |  --------  |  --------  |
                 |            |  EVC       |            |
                 |<------------------------------------>|
                 |            |            |            |
                 |    OVC1    |   OVC2     |    OVC3    |
                 |<---------->|<---------->|<---------->|
                 |            |            |            |

5.2.6.  Extranet VPNs

   There are some cases where a particular VPN needs access to resources
   (servers, hosts, etc.) that are external.  Those resources may be
   located in another VPN.

                    +-----------+           +-----------+
                   /             \         /             \
        Site A -- |    VPN A      |  ---  |    VPN B      | --- Site B
                   \             /         \             / (Shared
                    +-----------+           +-----------+   resources)

   In the figure above, VPN B has some resources on Site B that need to
   be available to some customers/partners.  VPN A must be able to
   access those VPN B resources.

   Such a VPN connection scenario can be achieved via a VPN policy as
   defined in Section 5.5.2.2.  But there are some simple cases where a
   particular VPN (VPN A) needs access to all resources in another VPN
   (VPN B).  The model provides an easy way to set up this connection
   using the "extranet-vpns" container.

   The extranet-vpns container defines a list of VPNs a particular VPN
   wants to access.  The extranet-vpns container must be used on
   customer VPNs accessing extranet resources in another VPN.  In the
   figure above, in order to provide VPN A with access to VPN B, the
   extranet-vpns container needs to be configured under VPN A with an




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   entry corresponding to VPN B.  There is no service configuration
   requirement on VPN B.

   Readers should note that even if there is no configuration
   requirement on VPN B, if VPN A lists VPN B as an extranet, all sites
   in VPN B will gain access to all sites in VPN A.

   The "site-role" leaf defines the role of the local VPN sites in the
   target extranet VPN service topology.  Site roles are defined in
   Section 5.4.

   In the example below, VPN A accesses VPN B resources through an
   extranet connection.  A Spoke role is required for VPN A sites, as
   sites from VPN A must not be able to communicate with each other
   through the extranet VPN connection.

      <vpn-service>
          <vpn-id>VPNB</vpn-id>
          <vpn-service-topology>hub-spoke</vpn-service-topology>
      </vpn-service>
      <vpn-service>
          <vpn-id>VPNA</vpn-id>
          <vpn-service-topology>any-to-any</vpn-service-topology>
          <extranet-vpns>
              <extranet-vpn>
                  <vpn-id>VPNB</vpn-id>
                  <site-role>spoke-role</site-role>
              </extranet-vpn>
          </extranet-vpns>
      </vpn-service>

   This model does not define how the extranet configuration will be
   achieved.

   Any VPN interconnection scenario that is more complex (e.g., only
   certain parts of sites on VPN A accessing only certain parts of sites
   on VPN B) needs to be achieved using a VPN attachment as defined in
   Section 5.5.2, and especially a VPN policy as defined in
   Section 5.5.2.2.

5.2.7.  SVLAN ID Ethernet Tag

   Service providers have the option of inserting an outer VLAN tag (the
   S-tag) into the service frames from the subscriber to improve service
   scalability and customer VLAN transparency.

   The "svlan-id-ethernet-tag" is either the S-tag inserted at a UNI or
   the outer tag of ingress packets at an E-NNI.  These parameters are



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   included in the L2SM to facilitate other management system to
   generate proper configuration for the network elements.

   Ideally, all external interfaces (UNI and E-NNI) associated with a
   given service will have the same S-tag assigned.  However, this may
   not always be the case.  Traffic with all attachments using different
   S-tags will need to be "normalized" to a single service S-tag.  (One
   example of this is a multipoint service that involves multiple off-
   net OVCs terminating on the same E-NNI.  Each of these off-net OVCs
   will have a distinct S-tag which can be different from the S-tag used
   in the on-net part of the service.)

   S-VLAN ID Preservation and S-VLAN CoS Preservation apply between two
   ENNIs connected by an OVC.  This attribute does NOT affect ENNI to
   UNI frame exchange.  Preservation means that the value of S-VLAN ID
   and/or S-VLAN CoS at one ENNI must be equal to the value at a
   different ENNI connected by the OVC.  The purpose of the optional
   "svlan-id-ethernet-tag" leaf is to identify the service-wide
   "normalized S-tag".If optional "svlan-id-perservation" leaf is set to
   true, the "svlan-id-ethernet-tag" leaf MUST be configured.

5.2.8.  CVLAN ID Ethernet Tag

   An EVC can be set to preserve the CE-VLAN ID and CE-VLAN CoS from
   ingress to egress.  This is required when the subscriber is using the
   VLAN header information between its locations.  CE-VLAN ID
   Preservation and CE-VLAN CoS Preservation apply between two UNIs
   connected by EVC.  Preservation means that the value of CE-VLAN ID
   and/or CE-VLAN CoS at one UNI must be equal to the value at a
   different UNI connected by the same EVC.

   If All-to-One bundling is Enabled , then preservation applies to all
   Ingress service frames.  If All-to-One bundling is Disabled , then
   preservation applies to tagged Ingress service frames having CE-VLAN
   ID.

5.2.9.  CVLAN ID To SVC MAP

   When more than one service is multiplexed onto the same interface,
   ingress service frames are conditionally transmitted through one of
   the EVC/OVCs based upon pre-arranged customer VLAN to EVC mapping.
   Multiple customer VLANs can be bundled across the same EVC.

   "cvlan-id-to-svc-map", when applicable, contains the list of customer
   vlans to the service mapping in a free-form format.  In most cases,
   this will be the VLAN access-list for the inner 802.1q tag (the
   C-tag).




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5.2.10.  Service Level MAC Limit

   When multiple services are provided on the same network element, the
   MAC address table (and the Routing Information Base space for MAC-
   routes in the case of EVPN) is a shared common resource.  Service
   providers may impose a maximum number of MAC addresses learned from
   the subscriber for a single service instance, and may specify the
   action when the upper limit is exceeded: drop the packet, flood the
   packet, or simply send a warning log message.

   For point-to-point services, if MAC learning is disabled then the MAC
   address limit is not necessary.

   The optional "service-level-mac-limit" container contains the
   subscriber MAC address limit and information to describe the action
   when the limit is exceeded.

5.2.11.  Load Balance Option

   As the subscribers start to deploy more 10G or 100G Ethernet
   equipment in their network, the demand for high bandwidth Ethernet
   connectivity services increases.  These high bandwidth service
   requests also pose challenges on capacity planning and service
   delivery in the provider's network, especially when the contractual
   bandwidth is at, or close to, the speed of physical links of the
   service provider's core network.  Because of the encapsulation
   overhead, the provider cannot deliver the throughput in the service
   level agreement over a single link.  Although there may be bundled
   aggregation links between core network elements, or Equal Cost
   Multiple Paths (ECMP) in the network, an Ethernet-over-MPLS (EoMPLS)
   PWE or VxLAN circuit is still considered with a single data flow to a
   router or switch which uses the normal IP five-tuples in the hashing
   algorithm.

   Without burdening the core routers with additional processing of deep
   inspection into the payload, the service provider now has the option
   of inserting a flow or entropy label into the EoMPLS frames, or using
   different source UDP ports in case of VxLAN/EVPN, at ingress PE to
   facility load-balancing on the subsequent nodes along the path.  The
   ingress PE is in a unique position to see the actual unencapsulated
   service frames and identify data flows based on the original Ethernet
   and IP header.

   On the other hand, not all Layer 2 Ethernet VPNs are suited for load-
   balancing across diverse ECMP paths.  For example, a Layer 2 Ethernet
   service transported over a single RSVP signaled Label Switched Path
   will not take multiple ECMP routes.  Or if the subscriber is




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   concerned about latency/jitter, then diverse path load-balancing can
   be undesirable.

   The optional "load-balance-option" container is used to capture the
   load-balancing agreement between the subscriber and the provider.  If
   the "load-balance" Boolean leaf is marked TRUE, then one of the
   following load-balance methods can be selected: "fat-pw", "entropy-
   label", or "vxlan-source-udp-port".  FAT pseudowires are used to
   load-balance traffic in the core when equal cost multipaths are used.
   The MPLS labels add an additional label to the stack, called the flow
   label, which contains the flow information of a VC.

5.2.12.  Service Protection

   Sometimes the subscriber may desire end-to-end protection at the
   service level for applications with high availability requirements.
   There are two protection schemes to offer redundant services:

   o  1+1 protection: In this scheme, the primary circuit will be
      protected by a backup circuit, typically meeting certain diverse
      path/fiber/site/node criteria.  Both primary and protection
      circuits are provisioned to be in the active forwarding state.
      The subscriber may choose to send the same service frames across
      both circuits simultaneously.

   o  1:1 protection: In this scheme, a backup circuit to the primary
      circuit is provisioned.  Depending on the implementation
      agreement, the protection circuits may either always be in active
      forwarding state, or may only become active when a faulty state is
      detected on the primary circuit.

   The optional "service-protection" container is used to capture the
   desired service protection agreement between subscriber and provider.

5.2.13.  Multicast Service

   Multicast in L2VPNs is described in [RFC5501][RFC7117].

   If multicast support is required for an L2VPN, some global multicast
   parameters are required as input for the service request.  When a CE
   sends (1) Broadcast, (2) Multicast, or (3) Unknown destination
   unicast, replication occurs at ingress PE, therefore three traffic
   type is supported.

   Users of this model will need to provide the flavors of trees that
   will be used by customers within the L2VPN (customer tree).  The
   proposed model supports bidirectional, shared, and source-based trees




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   (and can be augmented).  Multiple flavors of trees can be supported
   simultaneously.

                                   Operator network
                                   ______________
                                  /               \
                                 |                 |
                          (SSM tree)               |
    Recv -- Site2 ------- PE2             |
                                 |             PE1 --- Site1 --- Source1
                                 |                 |        \
                                 |                 |         -- Source2
                                 |                 |
                           (ASM tree)              |
    Recv -- Site3 ------- PE3             |
                                 |                 |
                           (SSM tree)              |
    Recv -- Site4 ------- PE4             |
                                 | /               |
    Recv -- Site5 --------                |
                           (ASM tree)              |
                                 |                 |
                                  \_______________/

   Group to port mappings can be created using the "rp-group-mappings"
   leaf.  Two group to port mapping method are supported:

   o  Static configuration of multicast Ethernet addresses and ports/
      interfaces.

   o  Multicast control protocol based on Layer-2 technology that
      signals mappings of multicast addresses to ports/interfaces, such
      as Generic Attribute Registration Protocol / GARP Multicast
      Registration Protocol (GARP/GMRP) [802.1D].

5.3.  Site Overview

   A site represents a connection of a customer office to one or more
   VPN services.












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                                                       +-------------+
                                                      /               \
        +------------------+                   +-----|      VPN1       |
        |                  |                   |      \               /
        |  New York Office |------ (site) -----+       +-------------+
        |                  |                   |       +-------------+
        +------------------+                   |      /               \
                                               +-----|      VPN2       |
                                                      \               /
                                                       +-------------+

   The "site" container is used for the provider to store information of
   detailed implementation arrangements made with either the customer or
   peer operators at each inter-connect location.

   We are restricting the L2SM to exterior interfaces only, so all
   internal interfaces and the underlying topology are outside the scope
   of L2SM.

   Typically, the following characteristics of a site interface handoff
   need to be documented as part of the service design:

   Unique identifier (site-id):  An arbitrary string to uniquely
      identify the site within the overall network infrastructure.  The
      format of site-id is determined by the local administration of the
      VPN service.

   Site Type (site-type):  Defines the way the VPN multiplexing is done.

   Device (device):  The customer can request one or more customer
      premise equipments from the service provider for a particular
      site.

   Management (management):  Defines the model of management of the
      site, for example: type, management-transport, address.

   Location (location):  The site location information to allow easy
      retrieval of data on which are the nearest available resources.

   Site diversity (site-diversity):  Presents some parameters to support
      site diversity.

   Signaling Options(signaling-options):  Defines which protocol or
      signaling must be activated between the subscriber and the
      provider.

   Load balancing (load-balance-options):  Defines the load-balancing
      agreement information between the subscriber and provider.



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   Site Network Accesses (site-network-accesses):  Defines the list of
      ports to the sites and their properties: especially bearer,
      connection and service parameters.

   A site-network-access represents an Ethernet logical connection of a
   site.  A site may have multiple site-network-accesses.

        +------------------+             Site
        |                  |-----------------------------------
        |                  |****** (site-network-access#1) ******
        |  New York Office |
        |                  |****** (site-network-access#2) ******
        |                  |-----------------------------------
        +------------------+

   Multiple site-network-accesses are used, for instance, in the case of
   multihoming.  Some other meshing cases may also include multiple
   site-network-accesses.

   The site configuration is viewed as a global entity; we assume that
   it is mostly the management system's role to split the parameters
   between the different elements within the network.  For example, in
   the case of the site-network-access configuration, the management
   system needs to split the overall parameters between the PE
   configuration and the CE configuration.

5.3.1.  Devices and Locations

   The information in the "location" sub-container under a "site"and
   "device" container allows easy retrieval of data about which are the
   nearest available facilities and can be used for access topology
   planning.  It may also be used by other network orchestration
   component to choose the targeted upstream PE and downstream CE.
   Location is expressed in terms of postal information.

   A site may be composed of multiple locations.  All the locations will
   need to be configured as part of the "locations" container and list.
   A typical example of a multi-location site is a headquarters office
   in a city composed of multiple buildings.  Those buildings may be
   located in different parts of the city and may be linked by intra-
   city fibers (customer metropolitan area network).  In such a case,
   when connecting to a VPN service, the customer may ask for
   multihoming based on its distributed locations.








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          New York Site

        +------------------+             Site
        | +--------------+ |-----------------------------------
        | | Manhattan    | |****** (site-network-access#1) ******
        | +--------------+ |
        | +--------------+ |
        | | Brooklyn     | |****** (site-network-access#2) ******
        | +--------------+ |
        |                  |-----------------------------------
        +------------------+

   A customer may also request some premises equipment entities (CEs)
   from the SP via the "devices" container.  Requesting a CE implies a
   provider-managed or co-managed model.  A particular device must be
   ordered to a particular already-configured location.  This would help
   the SP send the device to the appropriate postal address.  In a
   multi-location site, a customer may, for example, request a CE for
   each location on the site where multihoming must be implemented.  In
   the figure above, one device may be requested for the Manhattan
   location and one other for the Brooklyn location.

   By using devices and locations, the user can influence the
   multihoming scenario he wants to implement: single CE, dual CE, etc.

5.3.2.  Signaling Option

   The "signaling-option" container captures service-wide attributes of
   the L2VPN instance.

   Although topology discovery or network device configuration is
   purposely out of scope for the L2SM model, certain VPN parameters for
   discovery are listed here.  The information can then be passed to
   other elements in the whole automation eco-system (such as the
   configuration engine) which will handle the actual service
   provisioning function.

   [RFC6074] describes the provisioning, auto-Discovery, and signaling
   in L2VPNs.  It specifies a number of L2VPN provisioning models, and
   further specifies the semantic structure of the endpoint identifiers
   required by each model, as well as the distribution of these
   identifiers by the discovery process, and then specifies how the
   endpoint identifiers are carried in the signaling protocols (e.g.
   LDP and L2TPv3).

   The "signaling-option" list uses the "type" as the index.  The "type"
   leaf is for the signaling protocol: BGP- L2VPN, BGP-EVPN, T-LDP or
   L2TP.



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5.3.2.1.  BGP L2VPN

   [RFC4761] and [RFC6624] describe the mechanism to auto-discover L2VPN
   VPLS/VPWS end points (CE-ID or VE-ID) and signal the label base and
   offset at the same time to allow remote PE to derive the VPN label to
   be used when sending packets to the advertising router.

   In addition [RFC6624] makes interesting considerations about the
   L2VPN Scaling scheme and the separation of Administrative
   Responsibilities between Customer and Service Provider.

   Due to the way auto-discovery operates, PEs that have at least one
   attachment circuit associated with a particular VPN service do not
   need to be specified explicitly.

   In the L2SM model, only the target community (or communities) is also
   not specified since the management system allocates the route target
   upon receiving VPN creation request.

   The "type" leaf under "mp-bgp-l2vpn" is an identityref to specify
   "vpws" or "vpls" sub-types.

5.3.2.2.  BGP EVPN

   Defined in [RFC7432], EVPN is an L2VPN technology based upon BGP MAC
   routing.  It provides similar functionality to BGP VPWS/VPLS with
   improvement around redundancy, multicast optimization, provisioning,
   and simplicity.

   Due to the way auto-discovery operates, PEs that have at least one
   attachment circuit associated with a particular VPN service do not
   need to be specified explicitly.

   In the L2SM model, only the target community (or communities) is also
   not specified since the management system allocates the route target
   upon receiving VPN creation request.

   The "type" leaf under "mp-bgp-evpn" is an identityref to specify
   "vpws" or "vpls" sub-types.

5.3.2.3.  LDP Pseudowires

   [RFC4762] specifies the method of using targeted LDP sessions between
   PEs to exchange VC label information.  This requires a configured
   full mesh of targeted LDP sessions between all PEs.

   As multiple attachment circuits may terminate on a single PE, this
   PE-to-PE mesh is not a per-site attribute.  All PEs related to the



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   L2VPN service will be listed in the "t-ldp-pwe" with associated "vc-
   id".

   The "type" leaf under "mp-bgp-evpn" is an identityref to specify
   "vpws" ,"vpls", "h-vpls"sub-types.  In case of "h-vpls", "qinq" leaf
   must be specified.

5.3.2.4.  PWE Encapsulation Type

   Based on [RFC4448], there are two types of Ethernet services: "Port-
   to-Port Ethernet PW emulation" and "Vlan-to-Vlan Ethernet PW
   emulation", commonly referred to as Type 5 and Type 4 respectively.
   This concept applies to both BGP L2VPN VPWS/VPLS and T-LDP signaled
   PWE implementations.

   The "pwe-encapsulation-type" has two types: "ethernet" and "ethernet-
   vlan".  If "signaling-option" is "mp-bgp-l2vpn" or "t-ldp-pwe", then
   "pwe-encapsulation-type" must be set one of "ethernet" and "ethernet-
   vlan" .

5.3.2.5.  PWE MTU

   During the signaling process of a BGP-L2VPN or T-LDP pseudowire, the
   pwe-mtu value is exchanged and must match at both ends.  By default,
   the pwe-mtu is derived from physical interface MTU of the attachment
   circuit minus the EoMPLS transport header.  In some cases, however,
   the physical interface on both ends of the circuit might not have
   identical MTU settings.  For example, due to 802.1ad q-in-q
   operation, an I-NNI will need an extra four bytes to accommodate the
   S-tag.  The inter-carrier E-NNI link may also have a different MTU
   size than the internal network interfaces.

   [RFC4448] requires the same MTU size on physical interfaces at both
   ends of the pseudowire.  In actual implementations, many router
   vendors have provided a knob to explicitly specify the pwe-mtu, which
   can then be decoupled from the physical interface MTU.

   When there is a mismatch between the physical interface MTU and
   configured pwe-mtu, the "allow-mtu-mismatch" leaf in the "pwe-mtu"
   contained enables definition of the required behavior.

5.3.2.6.  Control Word

   A control word is an optional 4-byte field located between the MPLS
   label stack and the Layer 2 payload in the pseudowire packet.  It
   plays a crucial role in Any Transport over MPLS (AToM).  The 32-bit
   field carries generic and Layer 2 payload-specific information,
   including a C-bit which indicates whether the control word will



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   present in the Ethernet over MPLS (EoMPLS) packets.  If the C-bit is
   set to 1, the advertising PE expects the control word to be present
   in every pseudowire packet on the pseudowire that is being signaled.
   If the C-bit is set to 0, no control word is expected to be present.

   Whether to include control word in the pseudowire packets MUST match
   on PEs at both ends of the pseudowire and it is non-negotiable during
   the signaling process.

   The use of a control-word applies to pseduowires signaled using
   either BGP L2VPN VPWS/VPLS or T-LDP.  It is a routing-instance level
   configuration parameter in many cases.

   The optional "control-word" leaf is a Boolean field in the L2SM model
   for the provider to explicitly specify whether the control-word will
   be signaled for the service instance.

5.3.2.7.  L2TP Pseudowires

   In the L2VPN framework , a LAC is a Provider Edge (PE) device.  In
   the LAC-LAC reference model, a LAC serves as a cross-connect between
   attachment circuits and L2TP sessions.  Each L2TP session acts as an
   emulated circuit, also known as pseudowire.  A pseudowire is used to
   bind two attachment circuits together.  For different L2VPN
   applications, different types of attachment circuits are defined.

   The "encapsulation-type" has one type,i.e.,l2tp type.

   The optional "control-word" leaf is a Boolean field in the L2SM model
   for the provider to explicitly specify whether the control-word will
   be signaled for the service instance.

5.3.3.  Site Network Accesses

   The L2SM includes a set of essential physical interface properties
   and Ethernet layer characteristics in the "site-network-accesses"
   container.  Some of these are critical implementation arrangements
   that require consent from both customer and provider.

   As mentioned earlier, a site may be multihomed.  Each logical network
   access for a site is defined in the "site-network-accesses"
   container.  The site-network-access parameter defines how the site is
   connected on the network and is split into three main classes of
   parameters:

   o  bearer: defines requirements of the attachment (below Layer 2).

   o  connection: defines Layer 2 protocol parameters of the attachment.



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   o  availability: defines the site's availability policy.  The
      availability parameters are defined in Section 5.2.8.

   The site-network-access has a specific type (site-network-access-
   type).  This document defines two types:

   o  point-to-point: describes a point-to-point connection between the
      SP and the customer.

   o  multipoint: describes a multipoint connection between the SP and
      the customer.

   The type of site-network-access may have an impact on the parameters
   offered to the customer, e.g., an SP may not offer encryption for
   multipoint accesses.  It is up to the provider to decide what
   parameter is supported for point-to-point and/or multipoint accesses;
   which is out of scope for this document.  Some containers proposed in
   the model may require extensions in order to work properly for
   multipoint accesses.

5.3.3.1.  Bearer

   The "bearer" container defines the requirements for the site
   attachment to the provider network that are below Layer 3.

   The bearer parameters will help to determine the access media to be
   used.

5.3.3.2.  Connection

   The "connection" container defines the layer 2 protocol parameters of
   The Attachment and provides connectivity between customer Ethernet
   switches.  Depending on the management mode, it refers to PE-CE- LAN
   segment addressing or CE-to-customer-LAN segment addressing.  In any
   case, it describes the responsibility boundary between the provider
   and the customer.  For a customer-managed site, it refers to the PE-
   CE LAN Segment connection.  For a provider-managed site, it refers to
   the CE-to-LAN Segment connection.

   The connection container presents two sets of link attributes:
   physical interface or optional LAG interface attributes.  These
   parameters are essential for the connection between customer and
   provider edge devices to establish properly.  The connection
   container also defines L2CP attribute to allow control plane protocol
   interaction between the CE devices and PE device.






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5.3.3.2.1.  Addressing

   If the Ethernet service is enabled on a logical unit on the
   connection at the interface, the connection
   addressing,"encapsulation-type ","sub-if-id" should be specified.

   The "connection" container also presents site specific (S-tag, C-tag)
   management options.  The overall S-tag for the Ethernet circuit and
   C-tag to SVC mapping, if applicable, has been placed in the service
   container.  The S-tag under "connection" should match the S-tag in
   the service container in most cases, however, vlan translation is
   required for the S-tag in certain deployment at the external facing
   interface or upstream PEs to "normalize" the outer VLAN tag to the
   service S-tag into the network and translate back to the site's S-tag
   in the opposite direction.  One example of this is with a Layer 2
   aggregation switch along the path: the S-tag for the SVC has been
   previously assigned to another service thus can not be used by this
   attachment circuit.

5.3.3.2.2.  Physical Interface

   For each physical interface (phy-interface), there are basic
   configuration parameters like port number and speed, interface MTU,
   auto-negotiation and flow-control settings, etc.  "encapsulation-
   type" is for user to select between Ethernet encapsulation (port-
   based) or Ethernet VLAN encapsulation (VLAN-based).  All allowed
   Ethertypes of ingress service frames can be listed under "ethertype".
   In addition, the customer and provider may decide to enable advanced
   features, such as LLDP, 802.3AH link OAM, MAC loop detection/
   prevention at a UNI, based on mutual agreement.If Loop avoidance is
   required, the attribute "uni-loop-prevention" must be set to TRUE.

5.3.3.2.3.  LAG Interface

   Sometimes, the customer may require multiple physical links bundled
   together to form a single, logical, point-to-point LAG connection to
   the service provider.  Typically, LACP (Link Aggregation Control
   Protocol) is used to dynamically manage adding or deleting member
   links of the aggregate group.  In general, LAG allows for increased
   service bandwidth beyond the speed of a single physical link while
   providing graceful degradation as failure occurs, thus increased
   availability.

   In the L2SM, there is a set of attributes under "LAG-interface"
   related to link aggregation functionality.  The customer and provider
   first need to decide on whether LACP PDU will be exchanged between
   the edge device by specifying the "LACP-state" to "On" or "Off".  If
   LACP is to be enabled, then both parties need to further specify



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   whether it will be running in active versus passive mode, plus the
   time interval and priority level of the LACP PDU.  The subscriber and
   provider can also determine the minimum aggregate bandwidth for a LAG
   to be considered valid path by specifying the optional "mini-link"
   attribute.  To enable fast detection of faulty links, micro-bfd runs
   independent UDP sessions to monitor the status of each member link.
   Subscriber and provider should consent to the BFD hello interval and
   hold time.

   Each member link will be listed under the LAG interface with basic
   physical link properties.  Certain attributes like flow-control,
   encapsulation type, allowed ingress Ethertype and LLDP settings are
   at the LAG level.

5.3.3.2.4.  L2CP Control

   Customer and Service provider should make pre-arrangement on whether
   to allow control plane protocol interaction between the CE devices
   and PE device.  To provide seamless operation with multicast data
   transport, the transparent operation of Ethernet control protocols
   (e.g., Spanning Tree Protocol [802.1D]) can be employed by customers.

   To support efficient dynamic transport, Ethernet multicast control
   frames (e.g., GARP/GMRP [802.1D]) can be used between CE and PE.
   However, solutions MUST NOT assume all CEs are always running such
   protocols (typically in the case where a CE is a router and is not
   aware of Layer-2 details).

   To facilitate interoperability between different Multiple System
   Operators (MSOs), interaction between the edge device of each
   administrative domain can be either allowed or keep each
   Administrative domain control plane separate on a per-protocol basis.
   the MEF has provided normative guidance on Layer 2 Control Protocol
   (L2CP) processing requirements for each service type.

   The destination MAC addresses of these L2CP PDUs fall within two
   reserved blocks specified by the IEEE 802.1 Working Group.  Packet
   with destination MAC in these multicast ranges have special
   forwarding rules.

   o  Bridge Block of Protocols: 01-80-C2-00-00-00 through
      01-80-C2-00-00-0F

   o  MRP Block of Protocols: 01-80-C2-00-00-20 through
      01-80-C2-00-00-2F

   Layer 2 protocol tunneling allows service providers to pass
   subscriber Layer 2 control PDUs across the network without being



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   interpreted and processed by intermediate network devices.  These
   L2CP PDUs are transparently encapsulated across the MPLS-enabled core
   network in Q-in-Q fashion.

   The "L2CP-control" container contains the list of commonly used L2CP
   protocols and parameters.  The service provider can specify DISCARD,
   PEER, or TUNNEL mode actions for each individual protocol.

   In addition, "provider-bridge-group" and "provider-bridge-mvrp"
   addresses are also listed in the L2CP container.

5.4.  Site Role

   A VPN has a particular service topology, as described in
   Section 5.1.3.  As a consequence, each site belonging to a VPN is
   assigned with a particular role in this topology.  The site-role leaf
   defines the role of the site in a particular VPN topology.

   In the any-to-any VPN service topology, all sites MUST have the same
   role, which will be "any-to-any-role".

   In the Hub-and-Spoke VPN service topology or the Hub and Spoke
   disjoint VPN service topology, sites MUST have a Hub role or a Spoke
   role.

5.5.  Site Belonging to Multiple VPNs

5.5.1.  Site VPN Flavor

   A site may be part of one or multiple VPNs.  The "site-type" defines
   the way the VPN multiplexing is done.  There are three possible types
   of external facing connections associated with an Ethernet VPN
   service and a site.  Therefore the current version of the model
   supports three flavors:

   o  site-vpn-flavor-single: The site belongs to only one VPN.

   o  site-vpn-flavor-multi: The site belongs to multiple VPNs, and all
      the logical accesses of the sites belong to the same set of VPNs.

   o  site-vpn-flavor-enni: The site represents an ENNI where two
      Ethernet service providers inter-connect with each other.

5.5.1.1.  Single VPN Attachment: site-vpn-flavor-single

   The figure below describes a single VPN attachment.  The site
   connects to only one VPN.




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                                                         +--------+
      +------------------+             Site             /          \
      |                  |-----------------------------|            |
      |                  |***(site-network-access#1)***|    VPN1    |
      |  New York Office |                             |            |
      |                  |***(site-network-access#2)***|            |
      |                  |-----------------------------|            |
      +------------------+                              \          /
                                                         +--------+

5.5.1.2.  MultiVPN Attachment: site-vpn-flavor-multi

   The figure below describes a site connected to multiple VPNs.

                                                           +---------+
                                                      +---/----+      \
   +------------------+             Site             /   |      \      |
   |                  |--------------------------------- |       |VPN B|
   |                  |***(site-network-access#1)******* |       |     |
   |  New York Office |                             |    |       |     |
   |                  |***(site-network-access#2)*******  \      |    /
   |                  |-----------------------------| VPN A+-----|---+
   +------------------+                              \          /
                                                      +--------+

   In the example above, the New York office is multihomed.  Both
   logical accesses are using the same VPN attachment rules, and both
   are connected to VPN A and VPN B.

   Reaching VPN A or VPN B from the New York office will be done via
   destination-based routing.  Having the same destination reachable
   from the two VPNs may cause routing troubles.  The customer
   administration's role in this case would be to ensure the appropriate
   mapping of its prefixes in each VPN.

5.5.1.3.  ENNI: site-vpn-flavor-enni

   A External Network-to-Network Interface (ENNI) scenario may be
   modeled using the sites container.  It is helpful for the SP to
   indicate that the requested VPN connection is not a regular site but
   rather is an ENNI, as specific default device configuration
   parameters may be applied in the case of ENNIs (e.g., ACLs, routing
   policies).








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            SP A                                             SP B
       -------------------                         -------------------
      /                   \                       /                   \
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +  (VSI1)---(VPN1)----(VSI1)  +                 |
     |                 + ASBR +               + ASBR +                 |
     |                 +  (VSI2)---(VPN2)----(VSI2)  +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +  (VSI1)---(VPN1)----(VSI1)  +                 |
     |                 + ASBR +               + ASBR +                 |
     |                 +  (VSI2)---(VPN2)----(VSI2)  +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
      \                   /                       \                   /
       -------------------                         -------------------

   The figure above describes an option A ENNI scenario that can be
   modeled using the sites container.  In order to connect its customer
   VPNs (VPN1 and VPN2) in SP B, SP A may request the creation of some
   site-network-accesses to SP B.  The site-vpn-flavor-enni will be used
   to inform SP B that this is an ENNI and not a regular customer site.

5.5.2.  Attaching a Site to a VPN

   Due to the multiple site-vpn flavors, the attachment of a site to an
   L2VPN is done at the site-network-access (logical access) level
   through the "vpn-attachment" container.  The vpn-attachment container
   is mandatory.  The model provides two ways to attach a site to a VPN:

   o  By referencing the target VPN directly.

   o  By referencing a VPN policy for attachments that are more complex.

   A choice is implemented to allow the user to choose the flavor that
   provides the best fit.






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5.5.2.1.  Referencing a VPN

   Referencing a vpn-id provides an easy way to attach a particular
   logical access to a VPN.  This is the best way in the case of a
   single VPN attachment.  When referencing a vpn-id, the site-role
   setting must be added to express the role of the site in the target
   VPN service topology.

      <site>
       <site-id>SITE1</site-id>
       <site-network-accesses>
        <site-network-access>
         <site-network-access-id>LA1</site-network-access-id>
         <vpn-attachment>
          <vpn-id>VPNA</vpn-id>
          <site-role>spoke-role</site-role>
         </vpn-attachment>
        </site-network-access>
        <site-network-access>
         <site-network-access-id>LA2</site-network-access-id>
         <vpn-attachment>
          <vpn-id>VPNB</vpn-id>
          <site-role>spoke-role</site-role>
         </vpn-attachment>
        </site-network-access>
       </site-network-accesses>
      </site>

   The example above describes a multiVPN case where a site (SITE1) has
   two logical accesses (LA1 and LA2), attached to both VPNA and VPNB.

5.5.2.2.  VPN Policy

   The "vpn-policy" list helps express a multiVPN scenario where a
   logical access belongs to multiple VPNs.

   As a site can belong to multiple VPNs, the vpn-policy list may be
   composed of multiple entries.  A filter can be applied to specify
   that only some LANs of the site should be part of a particular VPN.
   Each time a site (or LAN) is attached to a VPN, the user must
   precisely describe its role (site-role) within the target VPN service
   topology.









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      +--------------------------------------------------------------+
      |       Site1 ------ PE7                                       |
      +-------------------------+                 [VPN2]             |
                                |                                    |
      +-------------------------+                                    |
      |       Site2 ------ PE3               PE4 ------ Site3        |
      +----------------------------------+                           |
                                         |                           |
      +------------------------------------------------------------+ |
      |       Site4 ------ PE5           |   PE6 ------ Site5      | |
      |                                                            | |
      |                      [VPN3]                                | |
      +------------------------------------------------------------+ |
                                         |                           |
                                         +---------------------------+

   In the example above, Site5 is part of two VPNs: VPN3 and VPN2.  It
   will play a Hub role in VPN2 and an any-to-any role in VPN3.  We can
   express such a multiVPN scenario as follows:
































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      <site>
       <site-id>Site5</site-id>
       <vpn-policies>
        <vpn-policy>
         <vpn-policy-id>POLICY1</vpn-policy-id>
         <entries>
          <id>ENTRY1</id>
          <vpn>
           <vpn-id>VPN2</vpn-id>
           <site-role>hub-role</site-role>
          </vpn>
         </entries>
         <entries>
          <id>ENTRY2</id>
          <vpn>
           <vpn-id>VPN3</vpn-id>
           <site-role>any-to-any-role</site-role>
          </vpn>
         </entries>
        </vpn-policy>
       </vpn-policies>
       <site-network-accesses>
        <site-network-access>
         <site-network-access-id>LA1</site-network-access-id>
         <vpn-attachment>
          <vpn-policy-id>POLICY1</vpn-policy-id>
         </vpn-attachment>
        </site-network-access>
       </site-network-accesses>
      </site>

   Now, if a more-granular VPN attachment is necessary, filtering can be
   used.  For example, if LAN1 from Site5 must be attached to VPN2 as a
   Hub and LAN2 must be attached to VPN3, the following configuration
   can be used:
















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      <site>
       <site-id>Site5</site-id>
       <vpn-policies>
        <vpn-policy>
         <vpn-policy-id>POLICY1</vpn-policy-id>
         <entries>
          <id>ENTRY1</id>
          <filter>
           <lan-tag>LAN1</lan-tag>
          </filter>
          <vpn>
           <vpn-id>VPN2</vpn-id>
           <site-role>hub-role</site-role>
          </vpn>
         </entries>
         <entries>
          <id>ENTRY2</id>
          <filter>
           <lan-tag>LAN2</lan-tag>
          </filter>
           <vpn>
           <vpn-id>VPN3</vpn-id>
           <site-role>any-to-any-role</site-role>
          </vpn>
         </entries>
        </vpn-policy>
       </vpn-policies>
       <site-network-accesses>
        <site-network-access>
         <site-network-access-id>LA1</site-network-access-id>
         <vpn-attachment>
          <vpn-policy-id>POLICY1</vpn-policy-id>
         </vpn-attachment>
        </site-network-access>
       </site-network-accesses>
      </site>

5.6.  Deciding Where to Connect the Site

   The management system will have to determine where to connect each
   site-network-access of a particular site to the provider network
   (e.g., PE, aggregation switch).

   The current model proposes parameters and constraints that can
   influence the meshing of the site-network-access.

   The management system should honor any customer constraints.  If a
   constraint is too strict and cannot be fulfilled, the management



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   system must not provision the site and should provide relevant
   information to the user.  How the information is provided is out of
   scope for this document.  Whether or not to relax the constraint
   would then be left up to the user.

   Parameters are just hints for the management system for service
   placement.

   In addition to parameters and constraints, the management system's
   decision MAY be based on any other internal constraints that are left
   up to the SP: least load, distance, etc.

5.6.1.  Constraint: Device

   In the case of provider management or co-management, one or more
   devices have been ordered by the customer.  The customer may force a
   particular site-network-access to be connected on a particular device
   that he ordered.

          New York Site

        +------------------+             Site
        | +--------------+ |-----------------------------------
        | | Manhattan    | |
        | |           CE1********* (site-network-access#1) ******
        | +--------------+ |
        | +--------------+ |
        | | Brooklyn  CE2********* (site-network-access#2) ******
        | +--------------+ |
        |                  |-----------------------------------
        +------------------+

   In the figure above, site-network-access#1 is associated with CE1 in
   the service request.  The SP must ensure the provisioning of this
   connection.

5.6.2.  Constraint/Parameter: Site Location

   The location information provided in this model MAY be used by a
   management system to determine the target PE to mesh the site (SP
   side).  A particular location must be associated with each site
   network access when configuring it.  The SP MUST honor the
   termination of the access on the location associated with the site
   network access (customer side).  The "country-code" in the site
   location should be expressed as an ISO ALPHA-2 code.

   The site-network-access location is determined by the "location-
   flavor".  In the case of a provider-managed or co-managed site, the



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   user is expected to configure a "device-reference" (device case) that
   will bind the site-network-access to a particular device that the
   customer ordered.  As each device is already associated with a
   particular location, in such a case the location information is
   retrieved from the device location.  In the case of a customer-
   managed site, the user is expected to configure a "location-
   reference" (location case); this provides a reference to an existing
   configured location and will help with placement.

                                            POP#1 (New York)
                                         +---------+
                                         |   PE1   |
                    Site #1 ---...       |   PE2   |
                   (Atlantic City)       |   PE3   |
                                         +---------+

                                            POP#2 (Washington)
                                         +---------+
                                         |   PE4   |
                                         |   PE5   |
                                         |   PE6   |
                                         +---------+

                                            POP#3 (Philadelphia)
                                         +---------+
                                         |   PE7   |
                    Site #2 CE#1---...   |   PE8   |
                   (Reston)              |   PE9   |
                                         +---------+

   In the example above, Site #1 is a customer-managed site with a
   location L1, while Site #2 is a provider-managed site for which a CE
   (CE#1) was ordered.  Site #2 is configured with L2 as its location.
   When configuring a site-network-access for Site #1, the user will
   need to reference location L1 so that the management system will know
   that the access will need to terminate on this location.  Then, for
   distance reasons, this management system may mesh Site #1 on a PE in
   the Philadelphia POP.  It may also take into account resources
   available on PEs to determine the exact target PE (e.g., least
   loaded).  For Site #2, the user is expected to configure the site-
   network-access with a device-reference to CE#1 so that the management
   system will know that the access must terminate on the location of
   CE#1 and must be connected to CE#1.  For placement of the SP side of
   the access connection, in the case of the nearest PE used, it may
   mesh Site #2 on the Washington POP.






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5.6.3.  Constraint/Parameter: Access Type

   The management system needs to elect the access media to connect the
   site to the customer (for example, xDSL, leased line, Ethernet
   backhaul).  The customer may provide some parameters/constraints that
   will provide hints to the management system.

   The bearer container information SHOULD be the first piece of
   information considered when making this decision:

   o  The "requested-type" parameter provides information about the
      media type that the customer would like to use.  If the "strict"
      leaf is equal to "true", this MUST be considered a strict
      constraint so that the management system cannot connect the site
      with another media type.  If the "strict" leaf is equal to "false"
      (default) and if the requested media type cannot be fulfilled, the
      management system can select another media type.  The supported
      media types SHOULD be communicated by the SP to the customer via a
      mechanism that is out of scope for this document.

   o  The "always-on" leaf defines a strict constraint: if set to true,
      the management system MUST elect a media type that is "always-on"
      (e.g., this means no dial access type).

   o  The "bearer-reference" parameter is used in cases where the
      customer has already ordered a network connection to the SP apart
      from the L2VPN site and wants to reuse this connection.  The
      string used is an internal reference from the SP and describes the
      already-available connection.  This is also a strict requirement
      that cannot be relaxed.  How the reference is given to the
      customer is out of scope for this document, but as a pure example,
      when the customer ordered the bearer (through a process that is
      out of scope for this model), the SP may have provided the bearer
      reference that can be used for provisioning services on top.

   Any other internal parameters from the SP can also be used.  The
   management system MAY use other parameters, such as the requested
   "svc-input-bandwidth" and "svc-output-bandwidth", to help decide
   which access type to use.

5.6.4.  Constraint: Access Diversity

   Each site-network-access may have one or more constraints that would
   drive the placement of the access.  By default, the model assumes
   that there are no constraints, but allocation of a unique bearer per
   site-network-access is expected.





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   In order to help with the different placement scenarios, a site-
   network-access may be tagged using one or multiple group identifiers.
   The group identifier is a string, so it can accommodate both explicit
   naming of a group of sites (e.g., "multihomed-set1") and the use of a
   numbered identifier (e.g., 12345678).  The meaning of each group-id
   is local to each customer administrator, and the management system
   MUST ensure that different customers can use the same group-ids.  One
   or more group-ids can also be defined at the site level; as a
   consequence, all site-network-accesses under the site MUST inherit
   the group-ids of the site they belong to.  When, in addition to the
   site group-ids some group-ids are defined at the site-network-access
   level, the management system MUST consider the union of all groups
   (site level and site network access level) for this particular site-
   network-access.

   For an already-configured site-network-access, each constraint MUST
   be expressed against a targeted set of site-network-accesses.  This
   site-network-access MUST never be taken into account in the targeted
   set -- for example, "My site-network-access S must not be connected
   on the same POP as the site-network-accesses that are part of Group
   10."  The set of site-network-accesses against which the constraint
   is evaluated can be expressed as a list of groups, "all-other-
   accesses", or "all-other-groups".  The all-other-accesses option
   means that the current site-network-access constraint MUST be
   evaluated against all the other site-network-accesses belonging to
   the current site.  The all-other-groups option means that the
   constraint MUST be evaluated against all groups that the current
   site-network-access does not belong to.

   The current model proposes multiple constraint-types:

   o  pe-diverse: The current site-network-access MUST NOT be connected
      to the same PE as the targeted site-network-accesses.

   o  pop-diverse: The current site-network-access MUST NOT be connected
      to the same POP as the targeted site-network-accesses.

   o  linecard-diverse: The current site-network-access MUST NOT be
      connected to the same linecard as the targeted site-network-
      accesses.

   o  bearer-diverse: The current site-network-access MUST NOT use
      common bearer components compared to bearers used by the targeted
      site-network-accesses. "bearer-diverse" provides some level of
      diversity at the access level.  As an example, two bearer-diverse
      site-network-accesses must not use the same DSLAM, BAS, or Layer 2
      switch.




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   o  same-pe: The current site-network-access MUST be connected to the
      same PE as the targeted site-network-accesses.

   o  same-bearer: The current site-network-access MUST be connected
      using the same bearer as the targeted site-network-accesses.

   These constraint-types can be extended through augmentation.  Each
   constraint is expressed as "The site-network-access S must be
   <constraint-type> (e.g., pe-diverse, pop-diverse) from these <target>
   site-network-accesses."

   The group-id used to target some site-network-accesses may be the
   same as the one used by the current site-network-access.  This eases
   the configuration of scenarios where a group of site-network-access
   points has a constraint between the access points in the group.

5.7.  Route Distinguisher and Network Instance Allocation

   The route distinguisher (RD) is a critical parameter of BGP-based
   L2VPNs as described in [RFC4364] that provides the ability to
   distinguish common addressing plans in different VPNs.  As for route
   targets (RTs), a management system is expected to allocate a VSI on
   the target PE and an RD for this VSI.

   If a VSI already exists on the target PE and the VSI fulfills the
   connectivity constraints for the site, there is no need to recreate
   another VSI, and the site MAY be meshed within this existing VSI.
   How the management system checks that an existing VSI fulfills the
   connectivity constraints for a site is out of scope for this
   document.

   If no such VSI exists on the target PE, the management system has to
   initiate the creation of a new VSI on the target PE and has to
   allocate a new RD for this new VSI.

   The management system MAY apply a per-VPN or per-VSI allocation
   policy for the RD, depending on the SP's policy.  In a per-VPN
   allocation policy, all VSIs (dispatched on multiple PEs) within a VPN
   will share the same RD value.  In a per-VRF model, all VRFs should
   always have a unique RD value.  Some other allocation policies are
   also possible, and this document does not restrict the allocation
   policies to be used.

   The allocation of RDs MAY be done in the same way as RTs.  The
   examples provided in Section 6.2.1.1 could be reused in this
   scenario.





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   Note that an SP MAY configure a target PE for an automated allocation
   of RDs.  In this case, there will be no need for any backend system
   to allocate an RD value.

5.8.  Site Network Access Availability

   A site may be multihomed, meaning that it has multiple site-network-
   access points.  Placement constraints defined in previous sections
   will help ensure physical diversity.

   When the site-network-accesses are placed on the network, a customer
   may want to use a particular routing policy on those accesses.  The
   "site-network-access/availability" container defines parameters for
   site redundancy.  The "access-priority" leaf defines a preference for
   a particular access.  This preference is used to model load-balancing
   or primary/backup scenarios.  The higher the access-priority value,
   the higher the preference will be.  The "redundancy mode" attribute
   is defined for an multi-homing site and used to model single-active
   and active/active scenarios.  It allows for multiple active paths in
   forwarding state and for load-balancing options.

   The figure below describes how the access-priority attribute can be
   used.

      Hub#1 LAN (Primary/backup)          Hub#2 LAN (Load-sharing)
        |                                                     |
        |    access-priority 1          access-priority 1     |
        |--- CE1 ------- PE1            PE3 --------- CE3 --- |
        |                                                     |
        |                                                     |
        |--- CE2 ------- PE2            PE4 --------- CE4 --- |
        |    access-priority 2          access-priority 1     |

                                PE5
                                 |
                                 |
                                 |
                                CE5
                                 |
                            Spoke#1 site (Single-homed)

   In the figure above, Hub#2 requires load-sharing, so all the site-
   network-accesses must use the same access-priority value.  On the
   other hand, as Hub#1 requires a primary site-network-access and a
   backup site-network-access, a higher access-priority setting will be
   configured on the primary site-network-access.





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   Scenarios that are more complex can be modeled.  Let's consider a Hub
   site with five accesses to the network (A1,A2,A3,A4,A5).  The
   customer wants to load-share its traffic on A1,A2 in the nominal
   situation.  If A1 and A2 fail, the customer wants to load-share its
   traffic on A3 and A4; finally, if A1 to A4 are down, he wants to use
   A5.  We can model this easily by configuring the following access-
   priority values: A1=100, A2=100, A3=50, A4=50, A5=10.

   The access-priority scenario has some limitations.  An access-
   priority scenario like the previous one with five accesses but with
   the constraint of having traffic load-shared between A3 and A4 in the
   case where A1 OR A2 is down is not achievable.  But the authors
   believe that using the access-priority attribute will cover most of
   the deployment use cases and that the model can still be extended via
   augmentation to support additional use cases.

5.9.  SVC MTU

   The maximum MTU of subscriber service frames can be derived from the
   physical interface MTU by default, or specified under the "svc-mtu"
   leaf if it is different than the default number.

5.10.  Service

   The "service" container defines service parameters associated with
   the site.

5.10.1.  Bandwidth

   The service bandwidth refers to the bandwidth requirement between CE
   and PE.  The requested bandwidth is expressed as svc-input-bandwidth
   and svc-output-bandwidth.  Input/output direction is using customer
   site as reference: input bandwidth means download bandwidth for the
   site, and output bandwidth means upload bandwidth for the site.

   The service bandwidth is only configurable at the site-network-access
   level (i.e., for the site network access associated with the site).

   Using a different input and output bandwidth will allow service
   provider to know if a customer allows for asymmetric bandwidth access
   like ADSL.  It can also be used to set a rate-limit in a different
   way for upload and download on symmetric bandwidth access.

   The svc-input-bandwidth or svc-output-bandwidth has specific type.
   This document defines four types:

   o  bw-per-connection Bandwidth is per connection or site network
      access, providing rate enforcement for all service frames at the



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      interface that are associated with a particular connection or
      network access.

   o  bw-per-cos Bandwidth is per cos ,providing rate enforcement for
      all service frames for a given class of service with specific cos-
      id.

   o  bw-per-site bandwidth is per site, providing rate enforcement for
      all service frames that are associated with a particular site-id.

   o  opaque bandwidth is the total bandwidth that is not associated
      with any particular cos-id, site-id or site network access id.

   The svc-input-bandwidth or svc-output-bandwidth must include a "cos-
   id" parameter if the 'type' is set as 'bw-per-cos'. the cos-id can be
   assigned based on dot1p value in C-tag, or DSCP in IP header.
   Ingress service frames are metered against the bandwidth profile
   based on the cos- identifier.

   The svc-input-bandwidth or svc-output-bandwidth must include a "vpn-
   id" parameter if the 'type' is set as 'bw-per-connection'.  Multiple
   input/output-bandwidthper-cos-id can be associated with the same
   Ethernet VPN service.

5.10.2.  QoS

   The model defines QoS parameters as an abstraction:

   o  qos-classification-policy: Defines a set of ordered rules to
      classify customer traffic.

   o  qos-profile: Provides a QoS scheduling profile to be applied.

5.10.2.1.  QoS Classification

   QoS classification rules are handled by qos-classification-policy.
   The qos-classification-policy is an ordered list of rules that match
   a flow or application and set the appropriate target class of service
   (target-class-id).  The user can define the match using physical port
   reference or a more specific flow definition (based layer 2 source
   and destination MAC address, cos,dscp,cos-id, color-id etc.).  A
   "color-id" will be assigned to a service frame to identify its QoS
   profile conformance.  A service frame is "green" if it is conformant
   with "committed" rate of the bandwidth profile.  A Service Frame is
   "yellow" if it is exceeding the "committed" rate but conformant with
   the "excess" rate of the bandwidth profile.  Finally, a service frame
   is "red" if it is conformant with neither the "committed" nor
   "excess" rates of the bandwidth profile.



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   When a flow definition is used, the user can use a target-sites leaf-
   list to identify the destination of a flow rather than using
   destination addresses.  A rule that does not have a match statement
   is considered as a match-all rule.  A service provider may implement
   a default terminal classification rule if the customer does not
   provide it.  It will be up to the service provider to determine its
   default target class.

5.10.2.2.  QoS Profile

   User can choose between standard profile provided by the operator or
   a custom profile.  The qos-profile defines the traffic scheduling
   policy to be used by the service provider.

   A custom qos-profile is defined as a list of class of services and
   associated properties.  The properties are:

   o  byte-offset: The optional "byte-offset" indicates how many bytes
      in the service frame header are excluded from rate enforcement.

   o  rate-limit: Used to rate-limit the class of service.  The value is
      expressed as a percentage of the global service bandwidth.  When
      the qos-profile is implemented at CE side the svc-output-bandwidth
      is taken into account as reference.  When it is implemented at PE
      side, the svc-input-bandwidth is used.

   o  frame-delay: Used to define the latency constraint of the class.
      The latency constraint can be expressed as the lowest possible
      latency or a latency boundary expressed in milliseconds.  How this
      latency constraint will be fulfilled is up to the service provider
      implementation: a strict priority queueing may be used on the
      access and in the core network, and/or a low latency routing may
      be created for this traffic class.

   o  frame-jitter: Used to define the jitter constraint of the class.
      The jitter constraint can be expressed as the lowest possible
      jitter or a jitter boundary expressed in microseconds.  How this
      jitter constraint will be fulfilled is up to the service provider
      implementation: a strict priority queueing may be used on the
      access and in the core network, and/or a jitter-aware routing may
      be created for this traffic class.

   o  bandwidth: used to define a guaranteed amount of bandwidth for the
      class of service.  It is expressed as a percentage.  The
      "guaranteed-bw-percent" parameter uses available bandwidth as a
      reference.  When the qos-profile container is implemented on the
      CE side, svc-output-bandwidth is taken into account as a
      reference.  When it is implemented on the PE side, svc-input-



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      bandwidth is used.  By default, the bandwidth reservation is only
      guaranteed at the access level.  The user can use the "end-to-end"
      leaf to request an end-to-end bandwidth reservation, including
      across the MPLS transport network.  (In other words, the SP will
      activate something in the MPLS core to ensure that the bandwidth
      request from the customer will be fulfilled by the MPLS core as
      well.)  How this is done (e.g., RSVP reservation, controller
      reservation) is out of scope for this document.

   Some constraints may not be offered by an SP; in this case, a
   deviation should be advertised.  In addition, due to network
   conditions, some constraints may not be completely fulfilled by the
   SP; in this case, the SP should advise the customer about the
   limitations.  How this communication is done is out of scope for this
   document.

5.10.3.  Multicast

   The "broadcast-unknowunicast-multicast" container defines the type of
   site in the customer multicast service topology: source, receiver, or
   both.  These parameters will help the management system optimize the
   multicast service.

   Multiple multicast group to port mappings can be created using the
   "multicast-gp-address-mapping" list.  The "multicast-gp-address-
   mapping" defines multicast group address and port lag number.  Those
   parameters will help the SP select the appropriate association
   between interface and multicast group to fulfill the customer service
   requirement.

   A whole Layer-2 multicast frame (whether for data or control) SHOULD
   NOT be altered from a CE to CE(s) EXCEPT for the VLAN ID field,
   ensuring that it is transparently transported.  If VLAN IDs are
   assigned by the SP, they can be altered.

   For point-to-point services, the provider only needs to deliver a
   single copy of each service frame to the remote PE, regardless
   whether the destination MAC address of the incoming frame is unicast,
   multicast or broadcast.  Therefore, all service frames should be
   delivered unconditionally.

   B-U-M (Broadcast-UnknownUnicast-Multicast) frame forwarding in
   multipoint-to-multipoint services, on the other hand, involves both
   local flooding to other attachment circuits on the same PE and remote
   replication to all other PEs, thus consumes additional resources and
   core bandwidth.  Special B-U-M frame disposition rules can be
   implemented at external facing interfaces (UNI or E-NNI) to rate-




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   limit the B-U-M frames, in term of number of packets per second or
   bits per second.

   The threshold can apply to all B-U-M traffic, or one for each
   category.

5.11.  Site Management

   The "management" sub-container is intended for site management
   options, depending on the device ownership and security access
   control.  The followings are three common management models:

   CE Provider Managed:  The provider has the sole ownership of the CE
      device.  Only the provider has access to the CE.  The
      responsibility boundary between SP and customer is between CE and
      customer network.  This is the most common use case.

   CE Customer Managed:  The customer has the sole ownership of the CE
      device.  Only the customer has access to the CE.  In this model,
      the responsibility boundary between SP and customer is between PE
      and CE.

   CE Co-managed:  The provider has ownership of the CE device and
      responsible for managing the CE.  However, the provider grants the
      customer access to the CE for some configuration/monitoring
      purposes.  In this co-managed mode, the responsibility boundary is
      the same as for the provider-managed model.

   The selected management mode is specified under the "type" leaf.  The
   "address" leaf stores CE device management IP information.  And the
   "management-transport" leaf is used to identify the transport
   protocol for management traffic: IPv4 or IPv6.  Additional security
   options may be derived based on the particular management model
   selected.

5.12.  Security Filtering

5.12.1.  MAC Loop Protection

   MAC address flapping between different physical ports typically
   indicates a bridge loop condition in the subscriber network.
   Misleading entries in the MAC cache table can cause service frames to
   circulate around the network indefinitely and saturate the links
   throughout the provider's network, affecting other services in the
   same network.  In case of EVPN, it also introduces massive BGP
   updates and control plane instability.





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   The service provider may opt to implement a switching loop prevention
   mechanism at the external facing interfaces for multipoint-to-
   multipoint services by imposing a MAC address move threshold.

   The MAC move rate and prevention-type options are listed in the "mac-
   loop-prevention" container.

5.12.2.  MAC Address Limit

   The service provider may choose to impose a per-attachment circuit
   "mac-addr-limit" in addition to the service-level MAC limit, and
   specify the behavior when the limit is exceeded accordingly.

5.13.  Ethernet Service OAM

   The advent of Ethernet as a wide-area network technology brings
   additional requirements of end-to-end service monitoring and fault
   management in the carrier network, particularly in the area of
   service availability and Mean Time To Repair (MTTR).  Ethernet
   Service OAM in the L2SM refers to the combined protocol suites of
   IEEE 802.1ag ([IEEE-802-1ag]) and ITU-T Y.1731 ([ITU-T-Y-1731]).

   Generally speaking, Ethernet Service OAM enables service providers to
   perform service continuity check, fault-isolation, and packet delay/
   jitter measurement at per customer per EVC granularity.  The
   information collected from Ethernet Service OAM data sets is
   complementary to other higher layer IP/MPLS OSS tools to ensure the
   required service level agreements (SLAs) can be meet.

   The 802.1ag Connectivity Fault Management (CFM) functional model is
   structured with hierarchical maintenance domains (MDs), each assigned
   a unique maintenance level.  Higher level MDs can be nested over
   lower level MDs.  However, the MDs cannot intersect.  The scope of
   each MD can be solely within a subscriber's network, solely within
   the provider's network, interact between the subscriber-to-provider
   or provider-to-provider edge equipment, or tunnel over another
   provider's network.

   Depending on the use case scenario, one or more maintenance end
   points (MEPs) can be placed on the external facing interface, sending
   CFM PDUs towards the core network (UP MEP) or downstream link (DOWN
   MEP).

   The "cfm-802.1-ag" sub-container under "port" currently presents two
   types of CFM maintenance association (MA): UP MEP for UNI-N to UNI-N
   Maintenance Association (MA) and DOWN MEP for UNI-N to UNI-C MA.  For
   each MA, the user can define the maintenance domain ID (MAID), MEP
   level, MEP direction, remote MEP ID, CoS level of the CFM PDUs,



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   Continuity Check Message (CCM) interval and hold time, alarm priority
   defect, CCM priority-type, etc.

   ITU-T Y.1731 Performance Monitoring (PM) provides essential network
   telemetry information that includes the measurement of Ethernet
   service frame delay, frame delay variation, frame loss, and frame
   throughput.  The delay/jitter measurement can be either one-way or
   two-way.  Typically, a Y.1731 PM probe sends a small amount of
   synthetic frames along with service frames to measure the SLA
   parameters.

   The "y-1731" sub-container under "port" contains a set of parameters
   for use to define the PM probe information, including MAID, local and
   remote MEP-ID, PM PDU type, message period and measurement interval,
   CoS level of the PM PDUs, loss measurement by synthetic or service
   frame options, one-way or two-way delay measurement, PM frame size,
   and session type.

5.14.  External ID References

   The service model sometimes refers to external information through
   identifiers.  As an example, to order a cloud-access to a particular
   cloud service provider (CSP), the model uses an identifier to refer
   to the targeted CSP.  If a customer is directly using this service
   model as an API (through REST or NETCONF, for example) to order a
   particular service, the SP should provide a list of authorized
   identifiers.  In the case of cloud-access, the SP will provide the
   associated identifiers for each available CSP.  The same applies to
   other identifiers, such as std-qos-profile.

   How an SP provides the meanings of those identifiers to the customer
   is out of scope for this document.

5.15.  Defining NNIs and Inter-AS support

   An autonomous system (AS) is a single network or group of networks
   that is controlled by a common system administration group and that
   uses a single, clearly defined routing protocol.  In some cases, VPNs
   need to span different ASes in different geographic areas or span
   different SPs.  The connection between ASes is established by the SPs
   and is seamless to the customer.  Examples include:

   o  A partnership between SPs (e.g., carrier, cloud) to extend their
      VPN service seamlessly.

   o  An internal administrative boundary within a single SP (e.g.,
      backhaul versus core versus data center).




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   NNIs (network-to-network interfaces) have to be defined to extend the
   VPNs across multiple ASes.  [RFC4761] defines multiple flavors of VPN
   NNI implementations.  Each implementation has pros and cons; this
   topic is outside the scope of this document.  For example, in an
   Inter-AS option A, autonomous system border router (ASBR) peers are
   connected by multiple interfaces with at least one of those
   interfaces spanning the two ASes while being present in the same VPN.
   In order for these ASBRs to signal label blocks, they associate each
   interface with a Virtual Switching (VSI) instance and a Border
   Gateway Protocol (BGP) session.  As a result, traffic between the
   back-to-back VPLS is Ethernet.  In this scenario, the VPNs are
   isolated from each other, and because the traffic is ethernet, QoS
   mechanisms that operate on Ethernet traffic can be applied to achieve
   customer service level agreements (SLAs).

      --------                 --------------              -----------
     /        \               /              \            /           \
    | Cloud    |             |                |          |             |
    | Provider |-----NNI-----|                |----NNI---| Data Center |
    |  #1      |             |                |          |             |
     \        /              |                |           \           /
      --------               |                |            -----------
                             |                |
      --------               |   My network   |           -----------
     /        \              |                |          /           \
    | Cloud    |             |                |         |             |
    | Provider |-----NNI-----|                |---NNI---|  L2VPN      |
    |  #2      |             |                |         |  Partner    |
     \        /              |                |         |             |
      --------               |                |         |             |
                              \              /          |             |
                               --------------            \           /
                                     |                    -----------
                                     |
                                    NNI
                                     |
                                     |
                             -------------------
                            /                   \
                           |                     |
                           |                     |
                           |                     |
                           |     L2VPN Partner   |
                           |                     |
                            \                   /
                             -------------------





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   The figure above describes an SP network called "My network" that has
   several NNIs.  This network uses NNIs to:

   o  increase its footprint by relying on L2VPN partners.

   o  connect its own data center services to the customer L2VPN.

   o  enable the customer to access its private resources located in a
      private cloud owned by some CSPs.

5.15.1.  Defining an NNI with the Option A Flavor

              AS A                                          AS B
       -------------------                         -------------------
      /                   \                       /                   \
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +  (VSI1)---(VPN1)----(VSI1)  +                 |
     |                 + ASBR +               + ASBR +                 |
     |                 +  (VSI2)---(VPN2)----(VSI2)  +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +  (VSI1)---(VPN1)----(VSI1)  +                 |
     |                 + ASBR +               + ASBR +                 |
     |                 +  (VSI2)---(VPN2)----(VSI2)  +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
      \                   /                       \                   /
       -------------------                         -------------------

   In option A, the two ASes are connected to each other with physical
   links on ASBRs.  For resiliency purposes, there may be multiple
   physical connections between the ASes.  A VPN connection -- physical
   or logical (on top of physical) -- is created for each VPN that needs
   to cross the AS boundary, thus providing a back-to-back VPLS model.

   From a service model's perspective, this VPN connection can be seen
   as a site.  Let's say that AS B wants to extend some VPN connections
   for VPN C on AS A.  The administrator of AS B can use this service
   model to order a site on AS A.  All connection scenarios could be



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   realized using the features of the current model.  As an example, the
   figure above shows two physical connections that have logical
   connections per VPN overlaid on them.  This could be seen as a
   multiVPN scenario.  Also, the administrator of AS B will be able to
   choose the appropriate routing protocol (e.g., E-BGP) to dynamically
   exchange routes between ASes.

   This document assumes that the option A NNI flavor SHOULD reuse the
   existing VPN site modeling.

   Example: a customer wants its CSP A to attach its virtual network N
   to an existing L2VPN (VPN1) that he has from L2VPN SP B.

           CSP A                              L2VPN SP B

     -----------------                    -------------------
    /                 \                  /                   \
   |       |           |                |                     |
   |  VM --|       ++++++++  NNI    ++++++++                  |--- VPN1
   |       |       +      +_________+      +                  |   Site#1
   |       |--------(VSI1)---(VPN1)--(VSI1)+                  |
   |       |       + ASBR +         + ASBR +                  |
   |       |       +      +_________+      +                  |
   |       |       ++++++++         ++++++++                  |
   |  VM --|           |                |                     |--- VPN1
   |       |Virtual    |                |                     |   Site#2
   |       |Network    |                |                     |
   |  VM --|           |                |                     |--- VPN1
   |       |           |                |                     |   Site#3
    \                 /                  \                   /
     -----------------                    -------------------
                                                  |
                                                  |
                                                VPN1
                                               Site#4

   To create the VPN connectivity, the CSP or the customer may use the
   L2VPN service model that SP B exposes.  We could consider that, as
   the NNI is shared, the physical connection (bearer) between CSP A and
   SP B already exists.  CSP A may request through a service model the
   creation of a new site with a single site-network-access (single-
   homing is used in the figure).  As a placement constraint, CSP A may
   use the existing bearer reference it has from SP A to force the
   placement of the VPN NNI on the existing link.  The XML below
   illustrates a possible configuration request to SP B:

      <site>
          <site-id>CSP_A_attachment</site-id>



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          <location>
              <city>NY</city>
              <country-code>US</country-code>
          </location>
          <site-vpn-flavor>site-vpn-flavor-nni</site-vpn-flavor>
          <signaling-options>
              <signaling-option>
                 <type>bgp-l2vpn</type>
                   <mp-bgp-l2vpn>
                       <svc-id>12456487</svc-id>
                        <type>kompella</type>
                    </mp-bgp-l2vpn>
                </signaling-option>
          <signaling-options>
          <site-network-accesses>
           <site-network-access>
            <site-network-access-id>CSP_A_VN1</site-network-access-id>
                  <connection>
                      <vlan>
                        <vlan-id>17</vlan-id>
                      </vlan>
                      <physical-interface>
                       <encapsulation-type>dot1q</encapsulation-type>
                       </physical-interface>
                    </connection>
                         <service>
                           <svc-ingress-bandwidth>
                             <type>opaque</type>
                             <cir>450000000</cir>
                             <cbs>20000000</cbs>
                             <eir>1000000000</eir>
                             <ebs>200000000</ebs>
                           </svc-ingress-bandwidth>
                           <svc-egress-bandwidth>
                             <cir>350000000</cir>
                             <cbs>10000000</cbs>
                             <eir>800000000</eir>
                             <ebs>200000000</ebs>
                           </svc-egress-bandwidth>
                         </service>
                        <vpn-attachment>
                           <vpn-id>12456487</vpn-id>
                           <site-role>spoke-role</site-role>
                         </vpn-attachment>
           </site-network-access>
          </site-network-accesses>
          <management>
           <type>customer-managed</type>



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          </management>
      </site>

   The case described above is different from a scenario using the
   cloud-accesses container, as the cloud-access provides a public cloud
   access while this example enables access to private resources located
   in a CSP network.

5.15.2.  Defining an NNI with the Option B Flavor

             AS A                                          AS B
       -------------------                         -------------------
      /                   \                       /                   \
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +      +               +      +                 |
     |                 + ASBR +<---MP-BGP---->+ ASBR +                 |
     |                 +      +               +      +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +      +               +      +                 |
     |                 + ASBR +<---MP-BGP---->+ ASBR +                 |
     |                 +      +               +      +                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
      \                   /                       \                   /
       -------------------                         -------------------

   In option B, the two ASes are connected to each other with physical
   links on ASBRs.  For resiliency purposes, there may be multiple
   physical connections between the ASes.  The VPN "connection" between
   ASes is done by exchanging VPN routes through MP-BGP [RFC4761].

   There are multiple flavors of implementations of such an NNI.  For
   example:

   1.  The NNI is internal to the provider and is situated between a
       backbone and a data center.  There is enough trust between the
       domains to not filter the VPN routes.  So, all the VPN routes are




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       exchanged.  RT filtering may be implemented to save some
       unnecessary route states.

   2.  The NNI is used between providers that agreed to exchange VPN
       routes for specific RTs only.  Each provider is authorized to use
       the RT values from the other provider.

   3.  The NNI is used between providers that agreed to exchange VPN
       routes for specific RTs only.  Each provider has its own RT
       scheme.  So, a customer spanning the two networks will have
       different RTs in each network for a particular VPN.

   Case 1 does not require any service modeling, as the protocol enables
   the dynamic exchange of necessary VPN routes.

   Case 2 requires that an RT-filtering policy on ASBRs be maintained.
   From a service modeling point of view, it is necessary to agree on
   the list of RTs to authorize.

   In Case 3, both ASes need to agree on the VPN RT to exchange, as well
   as how to map a VPN RT from AS A to the corresponding RT in AS B (and
   vice versa).

   Those modelings are currently out of scope for this document.



























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           CSP A                               L3VPN SP B

      -----------------                    ------------------
     /                 \                  /                  \
    |       |           |                |                    |
    |  VM --|       ++++++++   NNI    ++++++++                |--- VPN1
    |       |       +      +__________+      +                |   Site#1
    |       |-------+      +          +      +                |
    |       |       + ASBR +<-MP-BGP->+ ASBR +                |
    |       |       +      +__________+      +                |
    |       |       ++++++++          ++++++++                |
    |  VM --|           |                |                    |--- VPN1
    |       |Virtual    |                |                    |   Site#2
    |       |Network    |                |                    |
    |  VM --|           |                |                    |--- VPN1
    |       |           |                |                    |   Site#3
     \                 /                 |                    |
      -----------------                  |                    |
                                          \                  /
                                           ------------------
                                                    |
                                                    |
                                                   VPN1
                                                  Site#4

   The example above describes an NNI connection between CSP A and SP
   network B.  Both SPs do not trust themselves and use a different RT
   allocation policy.  So, in terms of implementation, the customer VPN
   has a different RT in each network (RT A in CSP A and RT B in SP
   network B).  In order to connect the customer virtual network in CSP
   A to the customer IP VPN (VPN1) in SP network B, CSP A should request
   that SP network B open the customer VPN on the NNI (accept the
   appropriate RT).  Who does the RT translation depends on the
   agreement between the two SPs: SP B may permit CSP A to request VPN
   (RT) translation.

5.15.3.  Defining an NNI with the Option C Flavor














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             AS A                                           AS B
      -------------------                          -------------------
     /                   \                        /                   \
    |                     |                      |                     |
    |                     |                      |                     |
    |                     |                      |                     |
    |                 ++++++++ Multihop E-BGP ++++++++                 |
    |                 +      +                +      +                 |
    |                 +      +                +      +                 |
    |                 + RGW  +<----MP-BGP---->+ RGW  +                 |
    |                 +      +                +      +                 |
    |                 +      +                +      +                 |
    |                 ++++++++                ++++++++                 |
    |                     |                      |                     |
    |                     |                      |                     |
    |                     |                      |                     |
    |                     |                      |                     |
    |                     |                      |                     |
    |                 ++++++++ Inter-AS link ++++++++                  |
    |                 +      +_______________+      +                  |
    |                 +      +               +      +                  |
    |                 + ASBR +               + ASBR +                  |
    |                 +      +               +      +                  |
    |                 +      +_______________+      +                  |
    |                 ++++++++               ++++++++                  |
    |                     |                      |                     |
    |                     |                      |                     |
    |                     |                      |                     |
    |                 ++++++++ Inter-AS link ++++++++                  |
    |                 +      +_______________+      +                  |
    |                 +      +               +      +                  |
    |                 + ASBR +               + ASBR +                  |
    |                 +      +               +      +                  |
    |                 +      +_______________+      +                  |
    |                 ++++++++               ++++++++                  |
    |                     |                      |                     |
    |                     |                      |                     |
     \                   /                        \                   /
      -------------------                          -------------------

   From a VPN service's perspective, the option C NNI is very similar to
   option B, as an MP-BGP session is used to exchange VPN routes between
   the ASes.  The difference is that the forwarding plane and the
   control plane are on different nodes, so the MP-BGP session is
   multihop between routing gateway (RGW) nodes.  From a VPN service's
   point of view, modeling options B and C will be identical.





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5.16.  Inter-Provider support with EVC and OVC or NNI

   In the case where the ASes belong to different providers, one might
   imagine that providers would like to have fewer signaling sessions
   crossing the AS boundary and that the entities that terminate the
   sessions could be restricted to a smaller set of devices.  Two
   approach can be taken:

      (a) Inter-provider control connections to run only between the two
      border routers

      (b) Allow an end-to-end, multi-segment connectivity to be
      constructed out of several connectivity segments, without
      maintaining an end-to-end control connection.

   Inter-provider control connection described in (a) can be realized
   using techniques of section 5.15(i.e., defining NNI).  Multi-segment
   connectivity described in (b) can produce an inter-AS solution that
   more closely resembles option (b) in [RFC4364].  It can be realized
   using combination of Per Site connectivity and OVC at different
   segments, e.g., end to end connectivity between site_1 and Site 3 can
   be constructed by stitching network access connectivity within site_1
   with OVC1, OVC3, OVC4 and network access connectivity within
   site)3(See the following figure) Note that OVC can also be regarded
   as network access connectivity within a site and can be created as a
   normal site using L2SM service model.

     Site_1
           PE   ------           ------
            //o/      \\\\   ////      \\\\
           |  \--OVC1---- o o - - - - -    |
          |                |       OVC3\    |
           |  /--OVC2-----o o- - - -\   \  |
            \\o\      ////   \\\\    \   \  ------
     Site_2PE   ------           ----- \/o/\      \\\\
                                       |     \        |
                                      |        \- - -- oPE Site_3
                                       |      OVC4    |
                                  ------          ////
                              ////      /\o\  ----
                             |        /     |
                            |       /        |
                             |     OVC5     |
                              \\o/      ////
                              PE  ------
                       Site_4





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   In this figure, we use EBGP redistribution of L2VPN NLRI from AS to
   neighboring AS.  First, the PE routers use Internal BGP (IBGP) to
   redistribute L2VPN NLRI either to an ASBR, or to a route reflector of
   which an ASBR is a client.  The ASBR then uses EBGP to redistribute
   those L2VPN NLRI to an ASBR in another AS, which in turn distributes
   them to the PE routers in that AS, or perhaps to another ASBR which
   in turn distributes them, and so on.

   In this case, a PE can learn the address of an ASBR through which it
   could reach another PE to which it wishes to establish a
   connectivity.  That is, a local PE will receive a BGP advertisement
   containing L2VPN NLRI corresponding to an L2VPN instance in which the
   local PE has some attached members.  The BGP next-hop for that L2VPN
   NLRI will be an ASBR of the local AS.  Then, rather than building a
   control connection all the way to the remote PE, it builds one only
   to the ASBR.  A connectivity segment can now be established from the
   PE to the ASBR.  The ASBR in turn can establish a connectivity to the
   ASBR of the next AS, and stitching that connectivity to the
   connectivity from the PE as described in Section 3.5.4 and [RFC6073].
   Repeating the process at each ASBR leads to a sequence of
   connectivity segments that, when stitching together, connect the two
   PEs.

   Note that in the approach just described, the local PE may never
   learn the IP address of the remote PE.  It learns the L2VPN NLRI
   advertised by the remote PE, which need not contain the remote PE
   address, and it learns the IP address of the ASBR that is the BGP
   next hop for that NLRI.

   When this approach is used for VPLS, or for full-mesh VPWS, it leads
   to a full mesh of connectivity among the PEs, but it does not require
   a full mesh of control connections (LDP or L2TPv3 sessions).
   Instead, the control connections within a single AS run among all the
   PEs of that AS and the ASBRs of the AS.  A single control connection
   between the ASBRs of adjacent ASes can be used to support however
   many AS-to-AS connectivity segments are needed.

6.  Interaction with Other YANG Modules

   As expressed in Section 4, this service module is not intended to
   configure the network element, but is instantiated in a management
   system.

   The management system might follow modular design and comprise at
   least two different components:

   a.  The component instantiating the service model (let's call it the
       service component)



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   b.  The component responsible for network element configuration
       (let's call it the configuration component)

   In some cases, when a split is needed between the behavior and
   functions that a customer requests and the technology that the
   network operator has available to deliver the service
   [I-D.ietf-opsawg-service-model-explained], a new component can be
   separated out of the service component (let's call it the control
   component).  This component is responsible for network-centric
   operation and is aware of many features such as topology, technology,
   and operator policy.  As an optional component, it can use the
   service model as input and is not required at all if the control
   component delegates its control operations to the configuration
   component.

   In Section 7 we provide some example of translation of service
   provisioning requests to router configuration lines as an
   illustration.  In the NETCONF/YANG ecosystem, it is expected that
   NETCONF and YANG will be used between the configuration component and
   network elements to configure the requested service on those
   elements.

   In this framework, it is expected that YANG models will be used for
   configuring service components on network elements.  There will be a
   strong relationship between the abstracted view provided by this
   service model and the detailed configuration view that will be
   provided by specific configuration models for network elements such
   as those defined in [I-D.ietf-bess-l2vpn-yang] and
   [I-D.ietf-bess-evpn-yang].  Service components needing configuration
   on network elements in support of the service model defined in this
   document include:

   o  Network Instance definition including VPN policy expression.

   o  Physical interface.

   o  Ethernet layer (VLAN ID).

   o  QoS: classification, profiles, etc.

   o  Signaling Options: support of configuration of all protocols
      listed in the document, as well as vpn policies associated with
      these protocols.

   o  Ethernet Service OAM Support.






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7.  Service Model Usage Example

   As explained in Section 4, this service model is intended to be
   instantiated at a management layer and is not intended to be used
   directly on network elements.  The management system serves as a
   central point of configuration of the overall service.

   This section provides an example on how a management system can use
   this model to configure an L2VPN service on network elements.

   The example is for of a VPN service for 3 sites using point-to-point
   EVC and a Hub and Spoke VPN service topology as shown in Figure 7.
   Loadbalancing is not considered in this case.


   UNI Site1
   ............
   :          :             E-Line using P2P EVC
   :Spoke Site:-----PE1--------------------------+
   :          :                                  |        UNI Site3
   :..........:                                  |      ............
                                                 |      :          :
                                                PE3-----: Hub Site :
   UNI Site2                                     |      :          :
   ............                                  |      :..........:
   :          :             E-Line using P2P EVC |
   :Spoke Site:-----PE2--------------------------+
   :          :
   :..........:


              Figure 7: Reference Network for Simple Example

   The following XML describes the overall simplified service
   configuration of this VPN.
















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                 <vpn-service>
                   <vpn-id>12456487</vpn-id>
                   <svc-id-type>evpl</svc-id-type>
                   <evc>
                     <uni-list>
                       <uni>UNI1</uni>
                       <uni>UNI3</uni>
                     </uni-list>
                   </evc>
                   <svc-topo>hub-spoke</svc-topo>
                 </vpn-service>

                 <vpn-service>
                   <vpn-id>12456488</vpn-id>
                   <svc-id-type>evpl</svc-id-type >
                   <evc>
                     <uni-list>
                       <uni>UNI2</uni>
                       <uni>UNI3</uni>
                     </uni-list>
                   </evc>
                   <svc-topo>hub-spoke</svc-topo>
                 </vpn-service>

   When receiving the request for provisioning the VPN service, the
   management system will internally (or through communication with
   another OSS component) allocates VPN route-targets.  In this specific
   case two Route Targets (RTs) will be allocated (100:1 for Hubs and
   100:2 for Spokes).  The output below describes the configuration of
   Spoke UNI Site1.


              <site>
                <site-id>Spoke_Site1</site-id>
                <location>
                   <city>NY</city>
                   <country-code>US</country-code>
                </location>
                <signaling-options>
                  <signaling-option>
                    <type>bgp-l2vpn</type>
                    <bgp-l2vpn>
                       <svc-id>12456487</svc-id>
                       <type>kompella</type>
                    </mp-bgp-l2vpn>
                  </signaling-option>
                </signaling-options>
                <site-network-accesses>



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                  <site-network-access>
                    <network-access-id>Spoke_UNI-Site1</network-access-id>
                    <access-diversity>
                      <groups>
                        <group>
                          <group-id>20</group-id>
                        </group>
                      </groups>
                    <access-diversity>
                    <connection>
                      <vlan>
                        <vlan-id>17</vlan-id>
                      </vlan>
                      <physical-interface>
                        <encapsulation-type>dot1q</encapsulation-type>
                      </physical-interface>
                    </connection>
                    <service>
                      <svc-ingress-bandwidth>
                        <type>opaque</type>
                        <cir>450000000</cir>
                        <cbs>20000000</cbs>
                        <eir>1000000000</eir>
                        <ebs>200000000</ebs>
                      </svc-ingress-bandwidth>
                      <svc-egress-bandwidth>
                        <cir>350000000</cir>
                        <cbs>10000000</cbs>
                        <eir>800000000</eir>
                        <ebs>200000000</ebs>
                      </svc-egress-bandwidth>
                    </service>
                    <l2cp-protocol>
                      <stp-rstp-mstp>TUNNEL</stp-rstp-mstp>
                      <lldp>TRUE</lldp>
                    </l2cp-protocol>
                    <vpn-attachment>
                      <vpn-id>12456487</vpn-id>
                      <site-role>spoke-role</site-role>
                    </vpn-attachment>
                  </site-network-access>
                </site-network-accesses>
                <management>
                  <type>provider-managed</type>
                </management>
              </site>





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   When receiving the request for provisioning Spoke1 site, the
   management system MUST allocate network resources for this site.  It
   MUST first determine the target network elements to provision the
   access, and especially the PE router (and may be an aggregation
   switch).  As described in Section 5.3.1, the management system SHOULD
   use the location information and SHOULD use the access-diversity
   constraint to find the appropriate PE.  In this case, we consider
   Spoke1 requires PE diversity with Hub and that management system
   allocate PEs based on lowest distance.  Based on the location
   information, the management system finds the available PEs in the
   nearest area of the customer and picks one that fits the access-
   diversity constraint.

   When the PE is chosen, the management system needs to allocate
   interface resources on the node.  One interface is selected from the
   PE available pool.  The management system can start provisioning the
   PE node by using any mean (Netconf, CLI, ...).  The management system
   will check if a VFI is already present that fits the needs.  If not,
   it will provision the VFI: Route Distinguisher will come from
   internal allocation policy model, route-targets are coming from the
   vpn-policy configuration of the site (management system allocated
   some RTs for the VPN).  As the site is a Spoke site (site-role), the
   management system knows which RT must be imported and exported.  As
   the site is provider managed, some management route-targets may also
   be added (100:5000).  Standard provider VPN policies MAY also be
   added in the configuration.

   Example of generated PE configuration:

l2vpn vfi context one
  vpn id 12456487
     autodiscovery bgp signaling bgp
     ve id 1001      <----identify the PE routers within the VPLS domain
     ve range 50    <---- VE size
     route-distinguisher 100:3123234324
     route-target import 100:1
     route-target import 100:5000    <---- Standard SP configuration
     route-target export 100:2                 for provider managed CE
   !

   When the VFI has been provisioned, the management system can start
   configuring the access on the PE using the allocated interface
   information.  The tag or VLAN (e.g., service instance tag)is chosen
   by the management system.  One tag will be picked from an allocated
   subnet for the PE, another will be used for the CE configuration.
   LACP protocols will also be configured between PE and CE and due to
   provider managed model, the choice is up to service provider.  This
   choice is independent of the LACP protocol chosen by customer.



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   Example of generated PE configuration:

   !
   bridge-domain 1
    member Ethernet0/0 service-instance 100
    member vfi one

   !
   l2 router-id 10.100.1.1
   !

   interface Ethernet0/0
    no ip address
    service instance 100 ethernet
   encapsulation dot1q 100
    !

   !
   router bgp 1
    bgp log-neighbor-changes
    neighbor 10.100.1.4 remote-as 1
    neighbor 10.100.1.4 update-source Loopback0
    !
    address-family l2vpn vpls
     neighbor 10.100.1.4 activate
     neighbor 10.100.1.4 send-community extended
     neighbor 10.100.1.4 suppress-signaling-protocol ldp
    exit-address-family

   !
   interface vlan 100 <-- Associating the Attachment
     no ip address       Circuit with the VSI at the PE
     xconnect vfi PE1-VPLS-A
   !
   vlan 100
     state active

   As the CE router is not reachable at this stage, the management
   system can produce a complete CE configuration that can be uploaded
   to the node by manual operation before sending the CE to customer
   premise.  The CE configuration will be built as for the PE.  Based on
   the CE type (vendor/model) allocated to the customer and bearer
   information, the management system knows which interface must be
   configured on the CE.  PE-CE link configuration is expected to be
   handled automatically using the service provider OSS as both
   resources are managed internally.  CE to LAN interface parameters
   like dot1Q tag are derived from the ethernet-connection taking into
   account how management system distributes dot1Q tag between PE and CE



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   within subnet.  This will allow to produce a plug'n'play
   configuration for the CE.

   Example of generated CE configuration:

                    interface Ethernet0/1
                      switchport trunk allowed vlan none
                      switchport mode trunk
                      service instance 100 ethernet
                      encapsulation default
                      l2protocol forward cdp
                      xconnect 1.1.1.1 100 encapsulation mpls
                    !

8.  YANG Module

<CODE BEGINS> file "ietf-l2vpn-svc@2017-06-22.yang"
module ietf-l2vpn-svc {
namespace "urn:ietf:params:xml:ns:yang:ietf-l2vpn-svc";
prefix "l2svc";

import ietf-inet-types {
prefix inet;
}
import ietf-yang-types {
prefix yang;
}
import iana-if-type {
prefix ianaift;
}
organization
"IETF L2SM Working Group.";
contact
"WG List: l2sm@ietf.org
Editor: giuseppe.fioccola@telecomitalia.it";
description
"The YANG module defines a generic service configuration
model for Layer 2 VPN services common across all of the
vendor implementations.";
revision 2017-06-22{
description
"Initial revision -02 version";
reference
"draft-ietf-l2sm-l2vpn-service-model-02.txt
A YANG Data Model for L2VPN Service Delivery.";
}
/* Features */
feature multicast{



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description
"Enables multicast capabilities in a VPN.";
}
feature extranet-vpn{
description
"Extranet vpn";
}
feature L2CP-control {
description
"L2CP control";
}
feature input-bw {
description
"Input Bandwidth";
}
feature output-bw {
description
"Output Bandwidth";
}

feature uni-list {
description
"Enable support UNI list";
}

feature ovc-type {
description
"Enable support OVC type";
}
feature cloud-access {
description
"Allow VPN to connect to a Cloud Service
provider.";
}
feature oam-3ah {
description
"Enables support of OAM 802.3ah";
}
feature micro-bfd {
description
"Enables support of Micro-BFD";
}
feature bfd {
description
"Enables support of BFD";
}
feature signaling-options {
description



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"Enable support of signaling option";
}
feature site-diversity {
description
"Enables support of site diversity constraints";
}
feature encryption {
description
"Enables support of encryption";
}
feature always-on {
description
"Enables support for always-on access
constraint.";
}
feature requested-type {
description
"Enables support for requested-type access
constraint.";
}
feature bearer-reference {
description
"Enables support for bearer-reference access
constraint.";
}
feature qos {
description
"Enables support of Class of Services";
}
feature qos-custom {
description
"Enables support of custom qos profile";
}
feature lag-interface{
description
"Enable lag-interface";
}
feature vlan {
description
"Enable VLAN";
}
feature dot1q{
description
"Enable Dot1Q";
}
feature qinq {
description
"Enable QinQ";



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}
feature qinany{
description
"Enable QinAny";
}
feature vxlan {
description
"Enable VxLAN";
}

/* Typedefs */

typedef svc-id {
type string;
description
"Service ID";
}
typedef direction-type {
type string;
description
"Direction";
}
typedef evc-id-type {
type string;
description
"EVC ID type";
}
typedef ovc-id-type {
type string;
description
"OVC ID type";
}
typedef ccm-priority-type {
type uint8 {
range "0..7";
}
description
"A 3 bit priority value to be used in the VLAN tag, if present
in the transmitted frame.";
}
typedef control-mode {
type enumeration {
enum peer {
description
"Peer mode";
}
enum tunnel {
description



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"Tunnel mode";
}
enum discard {
description
"Discard mode";
}
}
description
"Defining a type of the control mode";
}
typedef neg-mode {
type enumeration {
enum full-duplex {
description
"Full duplex mode";
}
enum auto-neg {
description
"Auto negotiation mode";
}

}
description
"Defining a type of the negotiation mode";
}

/* Identities */
identity multicast-tree-type {
description
"Base identity for multicast tree type.";
}
identity ssm-tree-type {
base multicast-tree-type;
description
"Identity for SSM tree type.";
}
identity asm-tree-type {
base multicast-tree-type;
description
"Identity for ASM tree type.";
}
identity bidir-tree-type {
base multicast-tree-type;
description
"Identity for bidirectional tree type.";
}

identity mapping-type{



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description
"Identity mapping-type";
}
identity static-mapping{
base mapping-type;
description
"Identity for static mapping, i.e.,attach the interface
to the Multicast group as static member";
}
identity dynamic-mapping{
base mapping-type;
description
"Identity for dynamic mapping, i.e.,interface was added
to the Multicast group as a result of snooping";
}

identity tf-type{
description
"Identity traffic-type";
}
identity multicast-traffic {
base tf-type;
description
"Identity for multicast traffic";
}
identity broadcast-traffic {
base tf-type;
description
"Identity for broadcast traffic";
}
identity unknown-unicast-traffic {
base tf-type;
description
"Identity for unknown unicast traffic";
}
identity pwe-encapsulation-type{
description
"Identity pwe-encapsulation-type";
}
identity ethernet-over-mpls {
base pwe-encapsulation-type;
description
"Identity for ethernet over mpls";
}
identity ethernet-tagged-mpls {
base pwe-encapsulation-type;
description
"Identity for ethernet tagged over mpls";



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}

identity l2tp-pw-type {
description
"Identity for L2TP PW type";
}

identity encapsulation-type {
description
"Identity for encapsulation type";
}
identity ethernet-type {
base encapsulation-type;
description
"Identity for encapsulation type";
}
identity vlan-type {
base encapsulation-type;
description
"Identity for encapsulation type";
}

identity protection-model {
description
"Identity of protection model";
}

identity oneplusone{
base protection-model;
description
"In this scheme, the primary circuitEVC or OVC will be
protected by a backup circuitEVC or OVC, typically meeting certain
diverse path/fiber/site/node criteria.  Both primary and
protection circuits are provisioned to be in the active forwarding
state.  The subscriber may choose to send the same service frames
across both circuits simultaneously.";
}

identity one2one{
base protection-model;
description
"In this scheme, a backup circuit to the primary
circuit is provisioned.  Depending on the implementation
agreement, the protection circuits may either always be in active
forwarding state, or may only become active when a faulty state is
detected on the primary circuit.";
}




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identity eth-type {
description
"Identity of ethernet type";
}

identity bw-type {
description
"Identity of bandwidth";
}
identity bw-per-cos {
base bw-type;
description
"Bandwidth is per cos";
}
identity bw-per-evc-ovc {
base bw-type;
description
"Bandwidth is per evc or per ovc";
}
identity bw-per-port {
base bw-type;
description
"Bandwidth is per site network access";
}

identity opaque {
base bw-type;
description
"Opaque";
}
identity site-type {
description
"Identity of site type.";
}
identity uni {
base site-type;
description
"Identity of User Network Interface ";
}
identity enni {
base site-type;
description
"Identity of External Network to Network Interface";
}

identity service-type {
description
"Identity of service type.";



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}
identity vpws {
base service-type;
description
" point-to-point Virtual Private Wire Services(VPWS) type.";
}
identity pwe3 {
base service-type;
description
" Pseudo-Wire Emulation Edge to
Edge(PWE3)Service type. .";

}
identity evpn {
base service-type;
description
"Ethernet VPN Service Type,
Ethernet VPNs are specified in RFC 7432";
}

identity vpls-ldp {
base service-type;
description
"LDP based multipoint Virtual Private LAN services (VPLS) Service Type.
This VPLS uses LDP-signaled Pseudowires";
}

identity vpls-bgp {
base service-type;
description
"BGP based multipoint Virtual Private LAN services (VPLS) Service Type.
This VPLS uses a Border Gateway Protocol (BGP) control plane as
described in RFC4761 and RFC6624. ";
}
identity epl {
base service-type;
description
"Ethernet Private Line (EPL) Service Type. ";
}
identity evpl {
base service-type;
description
"Ethernet Virtual Private Line (EVPL) Service Type. ";
}

identity ep-lan {
base service-type;
description



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" Ethernet Private LAN (EP-LAN)Service Type. ";
}
identity evp-lan {
base service-type;
description
" Ethernet Virtual Private LAN (EVP-LAN)Service Type. ";
}

identity bundling-type {
description
"Bundling type.";
}
identity bundling {
base bundling-type;
description
"Identity for bundling";
}
identity all2one-Bundling {
base bundling-type;
description
"Identity for all to one bundling";
}
identity color-id {
description
"Identity of color id";
}
identity color-id-evc {
base color-id;
description
"Identity of color id base on EVC";
}
identity color-id-evc-cvlan {
base color-id;
description
"Identity of color id base on EVC and CVLAN ";
}
identity cos-id {
description
"Identity of class of service id";
}
identity cos-id-evc {
base cos-id;
description
"Identity of cos id based on EVC";
}
identity cos-id-evc-pcp {
base cos-id;
description



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"Identity of cos id based on EVC and PCP";
}
identity cos-id-evc-dscp {
base cos-id;
description
"Identity of cos id based on EVC and DSCP";
}

identity cos-id-ovc-ep {
base cos-id;
description
"Identity of cos id based on OVC EP";
}
identity color-type {
description
"Identity of color types";
}
identity green {
base color-type;
description
"Identity of green type";
}
identity yellow {
base color-type;
description
"Identity of yellow type";
}
identity red {
base color-type;
description
"Identity of red type";
}
identity perf-tier-opt {
description
"Identity of performance tier option.";
}
identity metro {
base perf-tier-opt;
description
"Identity of metro";
}
identity regional {
base perf-tier-opt;
description
"Identity of regional";
}
identity continental {
base perf-tier-opt;



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description
"Identity of continental";
}
identity global {
base perf-tier-opt;
description
"Identity of global";
}

identity policing {
description
"Identity of policing type";
}
identity one-rate-two-color {
base policing;
description
"Identity of one-rate, two-color (1R2C)";
}
identity two-rate-three-color {
base policing;
description
"Identity of two-rate, three-color (2R3C)";
}
identity bum-type {
description
"Identity of BUM type";
}
identity broadcast {
base bum-type;
description
"Identity of broadcast";
}
identity unicast {
base bum-type;
description
"Identity of unicast";
}
identity multicast {
base bum-type;
description
"Identity of multicast";
}
identity loop-prevention-type{
description
"Identity of loop prevention";
}
identity shut {
base loop-prevention-type;



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description
"Identity of shut protection";
}
identity trap {
base loop-prevention-type;
description
"Identity of trap protection";
}
identity lacp-state {
description
"Identity of LACP state";
}
identity lacp-on {
base lacp-state;
description
"Identity of LCAP on";
}
identity lacp-off {
base lacp-state;
description
"Identity of LACP off";
}
identity lacp-mode {
description
"Identity of LACP mode";
}
identity lacp-passive {
base lacp-mode;
description
"Identity of LACP passive";
}
identity lacp-active {
base lacp-mode;
description
"Identity of LACP active";
}
identity lacp-speed {
description
"Identity of LACP speed";
}
identity lacp-fast {
base lacp-speed;
description
"Identity of LACP fast";
}
identity lacp-slow {
base lacp-speed;
description



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"Identity of LACP slow";
}
identity vpn-signaling-type {
description
"Identity of VPN signaling types";
}
identity bgp-l2vpn {
base vpn-signaling-type;
description
"Identity of bgp-l2vpn";
}
identity mp-bgp-evpn {
base vpn-signaling-type;
description
"Identity of mp-bgp-evpn";
}
identity t-ldp-pwe3{
base vpn-signaling-type;
description
"Identity of t-ldp-pwe";
}

identity l2tp-pw {
base vpn-signaling-type;
description
"Identity of l2tp-pw";
}

identity t-ldp-pwe-type{
description
"Identity for t-ldp-pwe-type";
}

identity vpws-type {
base t-ldp-pwe-type;
description
"Identity for VPWS";
}

identity vpls-type{
base t-ldp-pwe-type;
description
"Identity for vpls";
}

identity h-vpls{
base t-ldp-pwe-type;
description



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"Identity for h-vpls";
}

identity l2vpn-type {
description
"Layer 2 VPN types";
}
identity kompella {
base l2vpn-type;
description
"Use BGP as signaling protocol.";
}
identity martini {
base l2vpn-type;
description
"Use LDP as signaling protocol";
}
identity both {
base l2vpn-type;
description
"LDP based Signaling and BGP based Auto Discovery";
}

identity evpn-type {
description
"Ethernet VPN types";
}
identity pbb {
base evpn-type;
description
" Provider Backbone Bridging-EVPN";
}


identity management {
description
"Base identity for site management scheme.";
}
identity co-managed {
base management;
description
"Base identity for co-managed site.";
}
identity customer-managed {
base management;
description
"Base identity for customer managed site.";
}



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identity provider-managed {
base management;
description
"Base identity for provider managed site.";
}
identity address-family {
description
"Base identity for an address family.";
}
identity ipv4 {
base address-family;
description
"Identity for IPv4 address family.";
}
identity ipv6 {
base address-family;
description
"Identity for IPv6 address family.";
}
identity vpn-topology {
description
"Base identity for VPN topology.";
}
identity any-to-any {
base vpn-topology;
description
"Identity for any to any VPN topology.";
}
identity hub-spoke {
base vpn-topology;
description
"Identity for Hub'n'Spoke VPN topology.";
}
identity hub-spoke-disjoint {
base vpn-topology;
description
"Identity for Hub'n'Spoke VPN topology
where Hubs cannot talk between each other.";
}
identity site-role {
description
"Base identity for site type.";
}
identity any-to-any-role {
base site-role;
description
"Site in an any to any IPVPN.";
}



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identity spoke-role {
base site-role;
description

"Spoke Site in a Hub &amp; Spoke IPVPN.";
}
identity hub-role {
base site-role;
description
"Hub Site in a Hub &amp Spoke IPVPN.";
}
identity pm-type {
description
"Performance monitor type";
}
identity loss {
base pm-type;
description
"Loss measurement";
}
identity delay {
base pm-type;
description
"Delay measurement";
}
identity fault-alarm-defect-type {
description
"Indicating the alarm priority defect";
}
identity remote-rdi {
base fault-alarm-defect-type;
description
"Indicates the aggregate health of the remote MEPs.";
}
identity remote-mac-error {
base fault-alarm-defect-type;
description
"Indicates that one or more of the remote MEPs is
reporting a failure in its Port Status TLV or
Interface Status TLV.";
}
identity remote-invalid-ccm {
base fault-alarm-defect-type;
description
"Indicates that at least one of the Remote MEP
state machines is not receiving valid CCMs
from its remote MEP.";
}



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identity invalid-ccm {
base fault-alarm-defect-type;
description
"Indicates that one or more invalid CCMs has been
received and that 3.5 times that CCMs transmission
interval has not yet expired.";
}
identity cross-connect-ccm {
base fault-alarm-defect-type;
description
"Indicates that one or more cross connect CCMs has been
received and that 3.5 times of at least one of those
CCMs transmission interval has not yet expired.";
}
identity data-svc-frame-delivery {
description
"Delivery types";
}
identity discard {
base data-svc-frame-delivery;
description
"Service Frames are discarded.";
}
identity unconditional {
base data-svc-frame-delivery;
description
"Service Frames are unconditionally";
}
identity conditional {
base data-svc-frame-delivery;
description
"Service Frame are conditionally
delivered to the destination UNI.";
}
identity evc-type {
description
"Service topology Type";
}
identity point-to-point {
base evc-type;
description
"Point to Point.";
}
identity multipoint-to-multipoint {
base evc-type;
description
"Multipoint to Multipoint.";
}



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identity rooted-multipoint {
base evc-type;
description
"Rooted Multipoint.";
}


identity placement-diversity {
description
"Base identity for site placement
constraints";
}
identity bearer-diverse {
base placement-diversity;
description
"Identity for bearer diversity.
The bearers should not use common elements.";
}
identity pe-diverse {
base placement-diversity;
description
"Identity for PE diversity";
}
identity pop-diverse {
base placement-diversity;
description
"Identity for POP diversity";
}
identity linecard-diverse {
base placement-diversity;
description
"Identity for linecard diversity";
}
identity same-pe {
base placement-diversity;
description
"Identity for having sites connected
on the same PE";
}
identity same-bearer {
base placement-diversity;
description
"Identity for having sites connected
using the same bearer";
}
identity l2-access-type {
description
"This identify the access type



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of the vpn acccess interface";
}
identity untag {
base l2-access-type;
description
"Untag";
}
identity port {
base l2-access-type;
description
"Port";
}
identity dot1q {
base l2-access-type;
description
"Qot1q";
}
identity qinq {
base l2-access-type;
description
"QinQ";
}
identity sub-interface {
base l2-access-type;
description
"Create a default sub-interface and keep vlan";
}
identity vxlan {
base l2-access-type;
description
"Vxlan access into the vpn";
}
identity mac-learning-mode {
description
"MAC learning mode";
}
identity data-plane {
base mac-learning-mode;
description
"User MAC addresses are learned through ARP broadcast.";
}
identity control-plane {
base mac-learning-mode;
description
"User MAC addresses are advertised through EVPN-BGP";
}

/* Groupings */



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grouping vpn-service-cloud-access {
container cloud-accesses {
if-feature cloud-access;
list cloud-access {
key cloud-identifier;
leaf cloud-identifier {
 type string;
 description
   "Identification of cloud service. Local
   admin meaning.";
}
choice list-flavor {
 case permit-any {
   leaf permit-any {
   type empty;
   description
   "Allow all sites.";
   }
 }
 case deny-any-except {
   leaf-list permit-site {
   type leafref {
    path "/l2vpn-svc/sites/site/site-id";
   }
    description
    "Site ID to be authorized.";
   }
 }
 case permit-any-except {
   leaf-list deny-site {
   type leafref {
   path "/l2vpn-svc/sites/site/site-id";
  }
    description
    "Site ID to be denied.";
   }
 }
 description
   "Choice for cloud access policy.";
}
description
 "Cloud access configuration.";
}
description
"Container for cloud access configurations";
}
description
"Grouping for vpn cloud definition";



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}

grouping site-device {
container device {
list devices {
key "device-id";
leaf device-id {
 type string;
 description
   "Device ID";
}
leaf location {
 type leafref {
path "/l2vpn-svc/sites/site/locations/location/location-id";
}
 description
   "Site name";
}
container management {
 leaf address {
   type inet:ip-address;
   description
   "Address";
 }
 leaf management-transport {
   type identityref {
   base address-family;
   }
   description
   "Transport protocol used for management.";
 }
 description
   "Container for management";
}
description
 "List of devices";
}
description
"Devices configuration";
}
description
"Device parameters for the site.";
}

grouping site-management {
container management {
leaf type {
type identityref {



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 base management;
}
description
 "Management type of the connection.";
}
description
"Container for management";
}
description
"Grouping for management";
}

grouping site-vpn-policy {
container vpn-policies {
list vpn-policy {
key vpn-policy-id;
leaf vpn-policy-id {
 type string;
 description
   "Unique identifier for the VPN policy.";
}
list entries {
 key id;
 leaf id {
   type string;
   description
   "Unique identifier for the policy entry.";
 }

 container filter {
   choice lan {
  case lan-tag {
   leaf-list lan-tag {
   type string;
   description
   "List of lan-tags to be matched.";
   }
  }
    description
    "Choice for LAN matching type";
   }
   description
   "If used, it permit to split site LANs
   among multiple VPNs.
   If no filter used, all the LANs will be
   part of the same VPNs with the same
   role.";
 }



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 container vpn {
   leaf vpn-id {
   type leafref {
   path "/l2vpn-svc/vpn-services/"+
   "vpn-svc/vpn-id";
  }
  mandatory true;
  description
   "Reference to an IPVPN.";
   }
   leaf site-role {
   type identityref {
    base site-role;
  }
  default any-to-any-role;
  description
   "Role of the site in the IPVPN.";
   }
   description
   "List of VPNs the LAN is associated to.";
 }
 description
   "List of entries for export policy.";
}
description
 "List of VPN policies.";
}
description
"VPN policy.";
}
description
"VPN policy parameters for the site.";
}

grouping umb-frame-delivery {
leaf unicast-frame-delivery {
type identityref {
base data-svc-frame-delivery;
}
description
"Unicast Data Service Frame Delivery Mode
(unconditional[default], conditional, or discard).";
}
leaf multicast-frame-delivery {
type identityref {
base data-svc-frame-delivery;
}
description



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"Multicast Data Service Frame Delivery Mode
(unconditional[default], conditional, or discard).";
}
leaf broadcast-frame-delivery {
type identityref {
base data-svc-frame-delivery;
}
description
"Broadcast Data Service Frame Delivery Mode
(unconditional[default], conditional, or discard).";
}
description
"Grouping for unicast, mulitcast, broadcast frame delivery";
}

grouping customer-location-info {
container locations {
list location {
key location-id;
leaf location-id{
type string;
description
"Location ID";
}
leaf address {
type string;
description
 "Address (number and street) of the site.";
}
leaf zip-code {
type string;
description
 "ZIP code of the site.";
}
leaf state {
type string;
description
 "State of the site. This leaf can also be used to
  describe a region for country who does not have
  states.";
}
leaf city {
type string;
description
 "City of the site.";
}
leaf country-code {
type string;



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description
 "Country of the site.";
}
description
"List for location";
}
description
"Location of the site.";
}
description
"This grouping defines customer location parameters";
}

grouping site-diversity {
container site-diversity {
if-feature site-diversity;
container groups {
list group {
  key group-id;
  leaf group-id {
  type string;
  description
   "Group-id the site is belonging to";
  }
  description
  "List of group-id";
}
description
  "Groups the site is belonging to.
   All site network accesses will inherit those group
   values.";
}
description
"Diversity constraint type.";
}
description
"This grouping defines site diversity parameters";
}

grouping site-service {

list cvlan-id-to-svc-map {
key "svc-id type";
leaf svc-id {
type leafref {
  path "/l2vpn-svc/vpn-services/vpn-svc/vpn-id";
}
description



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  "EVC ID";
}
leaf type {
type identityref {
  base bundling-type;
}
description
  "Bundling type";
}
list cvlan-id {
key vid;
leaf vid {
  type identityref {
  base ianaift:iana-interface-type;
  }
  description
  "CVLAN ID";
}
description
  "List of CVLAN-ID to EVC Map configurations";
}
description
"List for cvlan-id to evc map configurations";
}

description
"This grouping defines site service parameters";
}

grouping service-protection {
container service-protection {
leaf protection-model {
type identityref {
 base protection-model;
  }
  description
  "Container of protection model configurations";
}
description
"Container of End-to-end Service Protection
 configurations";
}
description
"Grouping for service protection";
}

grouping vpn-service-multicast {
container multicast {



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if-feature multicast;
leaf enabled {
type boolean;
default false;
description
"Enables multicast.";
}
container customer-tree-flavors {
leaf-list tree-flavor {
type identityref {
base multicast-tree-type;
}
description
"Type of tree to be used.";
}
description
"Type of trees used by customer.";
}
leaf traffic-type {
type identityref {
base tf-type;
}
description
"Traffic Type";
}
leaf group-port-mapping {
type identityref {
base mapping-type;
}
description
"Traffic Type";
}
description
"Multicast global parameters for the VPN service.";
}
description
"Grouping for multicast VPN definition.";
}

grouping vpn-extranet {
container extranet-vpns {
if-feature extranet-vpn;
list extranet-vpn {
key vpn-id;

leaf vpn-id {
type svc-id;
description



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"Identifies the target VPN.";
}
leaf local-sites-role {
type identityref {
base site-role;

}
default any-to-any-role;
description
"This describes the role of the
local sites in the target VPN topology.";
}
description
"List of extranet VPNs the local VPN is attached to.";
}
description
"Container for extranet VPN configuration.";
}
description
"Grouping for extranet VPN configuration.
This provides an easy way to interconnect
all sites from two VPNs.";
}

grouping signaling-options-grouping {
list signaling-options {
key "type";
leaf type {
type identityref {
  base vpn-signaling-type;
}
description
  "VPN signaling types";
}
container bgp-l2vpn {
when "../type = 'bgp-l2vpn'" {
description
"Only applies when vpn signaling type is bgp-l2vpn.";
}

leaf vpn-id {
  type leafref{
  path "/l2vpn-svc/vpn-services/vpn-svc/vpn-id";
 }
  description
  "Identifies the target VPN";
}
leaf type {



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  type identityref {
  base l2vpn-type;
  }
  description
  "L2VPN types";
}
leaf address-family {
 type identityref {
   base address-family;
 }
 description
   "Address family used for management.";
}
description
  "Container for MP BGP L2VPN";
}
container mp-bgp-evpn {
when "../type = 'mp-bgp-evpn'" {
description
"Only applies when vpn signaling type is mp-bgp-evpn.";
}

leaf vpn-id {
  type leafref{
 path "/l2vpn-svc/vpn-services/vpn-svc/vpn-id";
}
  description
  "Identifies the target VPN";
}
leaf type {
  type identityref {
  base evpn-type;
  }
  description
  "L2VPN types";
}
leaf address-family {
 type identityref {
   base address-family;
 }
 description
   "Address family used for management.";
}
 leaf pwe-encapsulation-type {
 type identityref {
 base pwe-encapsulation-type;
}
 description



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  "Leaf for PWE Encapsulation Type configurations";
 }
container pwe-mtu {
 leaf allow-mtu-mismatch {
  type boolean;
  description
  "Allow MTU mismatch";
 }
 description
  "Container of PWE MTU configurations";
 }
leaf mac-learning-mode {
  type identityref {
  base mac-learning-mode;
  }
  description
  "Indicates through which plane MAC addresses are
  advertised.";
}
leaf arp-suppress {
  type boolean;
  default false;
  description
  "Indicates whether to suppress ARP broadcast.";
}
description
  "Container for MP BGP L2VPN";
}
container t-ldp-pwe {
when "../type = 't-ldp-pwe'" {
description
"Only applies when vpn signaling type is bgp-l2vpn.";
}

leaf type {
type identityref {
base t-ldp-pwe-type;
}
description
"T-LDP PWE type";
}
list pe-eg-list {
  key "service-ip-addr vc-id";
  leaf service-ip-addr {
  type inet:ip-address;
  description
  "Service ip lo address";
  }



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  leaf vc-id {
  type string;
  description
  "VC id";
  }
  description
  "List of PE/EG";
}

leaf control-word {
  type boolean;
   description
   "Control word configurations";
}
container qinq {
when "../type = 'h-vpls'" {
description
"Only applies when t-ldp pwe type is h-vpls.";
}
leaf s-tag {
type uint32;
description
"S-TAG";
}
leaf c-tag {
type uint32;
description
"C-TAG";
}
description
"Container for QinQ";
}
description
"Container of T-LDP PWE configurations";
}

container l2tp-pw{
leaf encapsulation-type {
type identityref {
base encapsulation-type;
}
description
"Encapsulation type";
}
container control-word {
description
"Container for control word";
}



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description
"Container for l2tp pw";
}

description
"List of VPN Signaling Option.";
}
description
"Grouping for signaling option";
}

grouping load-balance-grouping {
leaf fat-pw {
type boolean;
description
"Fat label is applied to Pseudowires across MPLS
 network";
}
leaf entropy-label {
type boolean;
description
"Entropy label is applied to IP forwarding,
 L2VPN or L3VPN across MPLS network";
}
leaf vxlan-source-port {
type string;
description
"Vxlan source port";
}
description
"Grouping for load balance ";
}

grouping operational-requirements-ops {
leaf actual-site-start {
type yang:date-and-time;
config false;
description
"Optional leaf indicating actual date
and time when the service at a particular
site actually started";
}
leaf actual-site-stop {
type yang:date-and-time;
config false;
description
"Optional leaf indicating actual date
and time when the service at a particular



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site actually stopped";
}
description
"This grouping defines some operational parameters
parameters";
}

grouping intra-mkt-grouping {
list intra-mkt {
key "metro-mkt-id mkt-name";
leaf metro-mkt-id {
type uint32;
description
 "Metro MKT ID";
}
leaf mkt-name {
type string;
description
 "MKT Name";
}
leaf ovc-id {
type leafref {
path "/l2vpn-svc/vpn-services/vpn-svc/ovc/ovc-list/ovc-id";
}
description
"OVC id";
}
leaf site-id {
type leafref{
path "/l2vpn-svc/sites/site/site-id";
}
description
"OVC identifier";
}
description
"List of intra-MKT";
}
description
"Grouping for intra-MKT";
}

grouping inter-mkt-service {
leaf inter-mkt-service{
type boolean;
description
"Indicate whether service is inter market service.";
}
description



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"Grouping for inter-MKT service";
}
grouping svc-type-grouping {
container evc {
leaf enabled {
type boolean;
description
"Enabled EVC";
}
leaf evc-type {
type identityref {
base evc-type;
}
description
"EVC type";
}
leaf number-of-pe {
type uint32;
config false;
description
 "Number of PE";
}
leaf number-of-site {
type uint32;
config false;
description
 "Number of Sites";
}
container uni-list {
if-feature uni-list;
list uni-list {
 key "uni-site-id";
 leaf uni-site-id {
   type string;
   description
  "UNI site Identifier";
 }
leaf off-net {
type boolean;
description
"Off net enable";
}
 description
   "List for UNIs";
}
description
 "Container for UNI List";
}



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leaf ce-vlan-preservation {
type boolean;
description
"CE vlan preservation";
}
leaf ce-vlan-cos-perservation {
type boolean;
description
"CE vlan COS preservation";
}
leaf service-multiplexing {
 type boolean;
 description
   "Service multiplexing";
}
description
"Container for Ethernet virtual connection.";
}
container ovc {
list ovc-list {
key ovc-id;
leaf ovc-id {
 type svc-id;
 description
   "OVC ID type";
}

leaf off-net {
 type boolean;
 description
   "Off net";
}
leaf svlan-cos-preservation {
type boolean;
description
"SVLAN CoS preservation";
}
leaf svlan-id-preservation {
type boolean;
description
"SVLAN ID preservation";
}
leaf svlan-id-ethernet-tag {
type string;
 description
 "SVLAN-ID/Ethernet Tag configurations";
}
leaf ovc-endpoint {



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type string;
description
"OVC Endpoint";
}
description
 "List for OVC";
}
description
"Container for OVC";
}
description
"Grouping of service types.";
}

grouping cfm-802-grouping {
leaf maid {
type string;
description
"MA ID";
}
leaf mep-id {
type uint32;
description
"Local MEP ID";
}
leaf mep-level {
type uint32;
description
"MEP level";
}
leaf mep-up-down {
type enumeration {
enum up {
 description
   "MEP up";
}
enum down {
 description
   "MEP down";
}
}
description
"MEP up/down";
}
leaf remote-mep-id {
type uint32;
description
"Remote MEP ID";



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}
leaf cos-for-cfm-pdus {
type uint32;
description
"COS for CFM PDUs";
}
leaf ccm-interval {
type uint32;
description
"CCM interval";
}
leaf ccm-holdtime {
type uint32;
description
"CCM hold time";
}
leaf alarm-priority-defect {
type identityref {
base fault-alarm-defect-type;
}
description
"The lowest priority defect that is
allowed to generate a Fault Alarm.
The non-existence of this leaf means
that no defects are to be reported";
}
leaf ccm-p-bits-pri {
type ccm-priority-type;
description
"The priority parameter for CCMs transmitted by the MEP";
}
description
"Grouping for 802.1ag CFM attribute";
}

grouping y-1731 {
list y-1731 {
key maid;
leaf maid {
type string;
description
 "MA ID ";
}
leaf mep-id {
type uint32;
description
 "Local MEP ID";
}



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leaf type {
type identityref {
 base pm-type;
}
description
 "Performance monitor types";
}
leaf remote-mep-id {
type uint32;
description
 "Remote MEP ID";
}
leaf message-period {
type uint32;
description
 "Defines the interval between OAM messages. The message
  period is expressed in milliseconds";
}
leaf measurement-interval {
type uint32;
description
 "Specifies the measurement interval for statistics. The
  measurement interval is expressed in seconds";
}
leaf cos {
type uint32;
description
 "Class of service";
}
leaf loss-measurement {
type boolean;
description
 "Whether enable loss measurement";
}
leaf synthethic-loss-measurement {
type boolean;
description
 "Indicate whether enable synthetic loss measurement";
}
container delay-measurement {
leaf enable-dm {
 type boolean;
 description
   "Whether to enable delay measurement";
}
leaf two-way {
 type boolean;
 description



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   "Whether delay measurement is two-way (true) of one-
   way (false)";
}
description
 "Container for delay measurement";
}
leaf frame-size {
type uint32;
description
 "Frame size";
}
leaf session-type {
type enumeration {
 enum proactive {
   description
   "Proactive mode";
 }
 enum on-demand {
   description
   "On demand mode";
 }
}
description
 "Session type";
}
description
"List for y-1731.";
}
description
"Grouping for y.1731";
}

grouping enni-site-info-grouping {
container site-info {
leaf site-name {
type string;
description
 "Site name";
}
leaf address {
type inet:ip-address;
description
 "Address";
}
leaf Edge-Gateway-Device-Info {
type string;
description
 "Edge Gateway Device Info ";



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}
description
"Container of site info configurations";
}
description
"Grouping for site information";
}

grouping site-security {
container security-filtering {
uses mac-loop-prevention-grouping;
container access-control-list {
list mac {
 key "mac-address";
 leaf mac-address {
   type yang:mac-address;
   description
   "MAC address";
 }
 description
   "List for MAC";
}
description
 "Container for access control";
}
uses mac-addr-limit-grouping;
description
"Security parameters";
}
description
"This grouping defines security parameters for a site";
}

grouping lacp-grouping {
container lacp {
leaf lacp-state {
type boolean;
description
 "LACP on/off";
}
leaf lacp-mode {
type boolean;
description
 "LACP mode";
}
leaf lacp-speed {
type boolean;
description



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 "LACP speed";
}
leaf mini-link {
type uint32;
description
 "Mini link";
}
leaf system-priority {
type uint16;
description
 "Indicates the LACP priority for the system.
  The range is from 0 to 65535.
  The default is 32768.";
}
container micro-bfd {
if-feature micro-bfd;
leaf micro-bfd-on-off {
 type enumeration {
   enum on {
   description
    "Micro-bfd on";
   }
   enum off {
  description
   "Micro-bfd off";
   }
 }
 description
   "Micro BFD ON/OFF";
}
leaf bfd-interval {
 type uint32;
 description
   "BFD interval";
}
leaf bfd-hold-timer {
 type uint32;
 description
   "BFD hold timer";
}
description
 "Container of Micro-BFD configurations";
}
container bfd {
if-feature bfd;
leaf bfd-enabled {
 type boolean;
 description



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   "BFD activation";
}
choice holdtime {
 case profile {
   leaf profile-name {
   type string;
   description
   "Service provider well known profile.";
   }
   description
   "Service provider well known profile.";
 }
 case fixed {
   leaf fixed-value {
  type uint32;
  units msec;
  description
   "Expected hold time expressed in msec.";
   }
 }
 description
   "Choice for hold time flavor.";
}
description
 "Container for BFD.";
}
container member-link-list {
list member-link {
 key "name";
 leaf name {
   type string;
   description
  "Member link name";
 }
 leaf port-speed {
   type uint32;
   description
   "Port speed";
 }
 leaf mode {
   type neg-mode;
   description
  "Negotiation mode";
 }
 leaf mtu {
   type uint32;
   description
   "MTU";



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 }
 container oam-802.3ah-link {
   if-feature oam-3ah;
   leaf enable {
   type boolean;
   description
   "Indicate whether support oam 802.3 ah link";
   }
   description
   "Container for oam 802.3 ah link.";
 }
 description
   "Member link";
}
description
 "Container of Member link list";
}
leaf flow-control {
type string;
description
 "Flow control";
}

leaf encapsulation-type {
type identityref {
base encapsulation-type;
}
description
"Encapsulation type";
}
leaf ethertype {
type identityref {
base eth-type;
}
description
 "Ether type";
}
leaf lldp {
type boolean;
description
  "LLDP";
}
description
"LACP";
}
description
"Grouping for lacp";
}



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grouping phy-interface-grouping {
container phy-interface {
leaf port-number {
type uint32;
description
 "Port number";
}
leaf port-speed {
type uint32;
description
 "Port speed";
}
leaf mode {
type neg-mode;
description
 "Negotiation mode";
}

leaf phy-mtu {
type uint32;
description
 "PHY MTU";
}
leaf flow-control {
type string;
description
 "Flow control";
}
leaf encapsulation-type {
type identityref {
base encapsulation-type;
}
description
"Encapsulation Type";
}
leaf ethertype {
type identityref{
 base eth-type;
}
description
 "Ethertype";
}
leaf lldp {
type boolean;
description
 "LLDP";
}
container oam-802.3ah-link {



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if-feature oam-3ah;
leaf enable {
type boolean;
description
  "Indicate whether support oam 802.3 ah link";
}
description
"Container for oam 802.3 ah link.";
}
leaf uni-loop-prevention {
type boolean;
description
 "If this leaf set to truth that the port automatically
  goes down when a physical loopback is detect.";
}
description
"Container of PHY Interface Attributes configurations";
}
description
"Grouping for phy interface.";
}

grouping lag-interface-grouping {
container lag-interface {
if-feature lag-interface;
list lag-interface {
key "lag-interface-number";
leaf lag-interface-number {
 type uint32;
 description
   "LAG interface number";
}
uses lacp-grouping;
description
 "List of LAG interfaces";
}
description
"Container of LAG interface attributes configuration";
}
description
"Grouping for LAG interface";
}
grouping l2-access-grouping {
container dot1q {
when "'../l2-access-type'='dot1q'";
if-feature dot1q;
leaf physical-inf {
type string;



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description
 "Physical Interface";
}
leaf c-vlan-id {
type uint32;
description
 "VLAN identifier";
}
description
"Qot1q";
}
container qinq {
when "'../l2-access-type'='qinq'";
if-feature qinq;

leaf s-vlan-id {
type uint32;
description
 "S-VLAN Identifier";
}
leaf c-vlan-id {
type uint32;
description
 "C-VLAN Identifier";
}
description
"QinQ";
}
container qinany {
if-feature qinany;
leaf s-vlan-id {
type uint32;
description
"S-Vlan ID";
}
description
"Container for Q in Any";
}
container vxlan {
when "'../l2-access-type'='vxlan'";
if-feature vxlan;
leaf vni-id {
type uint32;
description
  "VNI Identifier";
}
list peer-list {
key peer-ip;



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leaf peer-ip {
 type inet:ip-address;
 description
   "Peer IP";
}
description
 "List for peer IP";
}
description
"QinQ";
}
description
"Grouping for Layer2 access";
}

grouping ethernet-connection-grouping {
container connection {
container encapsulation-type {
leaf encapsulation-type {
type identityref {
base encapsulation-type;
}
description
"Encapsulation Type";
}
leaf eth-type {
type identityref {
base eth-type;
}
description
"Ethernet Type";
}
description
"Container for encapsulation type";
}

leaf esi {
type string;
description
"Ethernet segment id";
}
leaf interface-description {
type string;
description
"Interface description";
}
leaf sub-if-id {
when "'../l2-access-type'='sub-interface'";



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type uint32;
description
"Sub interface ID";
}
container vlan {
if-feature vlan;
leaf vlan-id {
 type uint32;
 description
   "VLAN-ID/Ethernet Tag configurations";
}
description
 "Abstract container for VLAN";
}
uses l2-access-grouping;
uses phy-interface-grouping;
uses lag-interface-grouping;
uses l2cp-grouping;
description
"Container for bearer";
}
description
"Grouping for bearer.";
}

grouping svc-mtu-grouping {
leaf svc-mtu {
type uint32;
description
"EVC MTU";
}
description
"Grouping for evc mtu";
}

grouping mac-addr-limit-grouping {
container mac-addr-limit {
leaf exceeding-option {
type uint32;
description
 "Exceeding option";
}
description
"Container of MAC-Addr limit configurations";
}
description
"Grouping for mac address limit";
}



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grouping availability-grouping {
container availability {
leaf access-priority {
type uint32;
description
"Access priority";
}
choice redundancy-mode {
 case single-active {
   leaf single-active {
   type boolean;
   description
    "Single active";
   }
   description
   "Single active case";
 }
 case all-active {
   leaf all-active {
   type boolean;
   description
   "All active";
   }
   description
   "All active case";
 }
 description
   "Redundancy mode choice";
}
description
"Container of availability optional configurations";
}
description
"Grouping for availability";
}

grouping l2cp-grouping {
container l2cp-control {
if-feature L2CP-control;
leaf stp-rstp-mstp {
type control-mode;
description
 "STP/RSTP/MSTP protocol type applicable to all UNIs";
}
leaf pause {
type control-mode;
description
 "Pause protocol type applicable to all UNIs";



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}
leaf lacp-lamp {
type control-mode;
description
 "LACP/LAMP  ";
}

leaf link-oam {
type control-mode;
description
 "Link OAM";
}
leaf esmc {
type control-mode;
description
 "ESMC";
}
leaf l2cp-802.1x {
type control-mode;
description
 "802.x";
}
leaf e-lmi {
type control-mode;
description
 "E-LMI";
}
leaf lldp {
type boolean;
description
 "LLDP protocol type applicable to all UNIs";
}
leaf ptp-peer-delay {
type control-mode;
description
 "PTP peer delay";
}
leaf garp-mrp {
type control-mode;
description
 "GARP/MRP";
}
leaf provider-bridge-group {
type control-mode;
description
 "Provider bridge group reserved MAC address
  01-80-C2-00-00-08";
}



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leaf provider-bridge-mvrp {
type control-mode;
description
 "Provider bridge MVRP reserved MAC address
  01-80-C2-00-00-0D";
}
description
"Container of L2CP control configurations";
}
description
"Grouping for l2cp control";
}

grouping B-U-M-grouping {
container broadcast-unknown-unicast-multicast  {
leaf multicast-site-type {
type enumeration {
enum receiver-only {
description
"The site only has receivers.";
}
enum source-only {
description
"The site only has sources.";
}
enum source-receiver {
description
"The site has both sources and receivers.";
}
}
default "source-receiver";
description
"Type of multicast site.";
}
list multicast-gp-address-mapping {
key id;
leaf id {
type uint16;
description
"Unique identifier for the mapping.";
}
leaf vlan-id {
 type uint32;
 description
   "the VLAN ID of the Multicast group";
}
leaf mac-gp-address {
type yang:mac-address;



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description
"the MAC address of the Multicast group";
}
leaf port-lag-number {
type uint32;
description
 "the ports/LAGs belonging to the Multicast group";
}
description
"List of Port to group mappings.";
}
leaf bum-overall-rate {
type uint32;
description
  "overall rate for BUM";
}
list bum-rate-per-type {
 key "type";
 leaf type {
   type identityref {
   base bum-type;
   }
   description
   "BUM type";
 }
 leaf rate {
   type uint32;
   description
   "rate for BUM";
}
description
 "List of rate per type";
}
description
"Container of broadcast, unknown unicast, and multicast configurations";
}
description
"Grouping for broadcast, unknown unicast, and multicast ";
}

grouping mac-loop-prevention-grouping {
container mac-loop-prevention {
leaf frequency {
type uint32;
description
 "Frequency";
}
leaf protection-type {



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type identityref {
 base loop-prevention-type;
}
description
 "Protection type";
}
leaf number-retries {
type uint32;
description
 "Number of retries";
}
description
"Container of MAC loop prevention.";
}
description
"Grouping for MAC loop prevention";
}

grouping ethernet-svc-oam-grouping {
container ethernet-service-oam {
leaf md-name {
type string;
description
 "Maintenance domain name";
}
leaf md-level {
type uint8;
description
 "Maintenance domain level";
}

container cfm-802.1-ag {
list n2-uni-c {
 key "maid";
 uses cfm-802-grouping;
 description
   "List of UNI-N to UNI-C";
}
list n2-uni-n {
 key "maid";
 uses cfm-802-grouping;
 description
  "List of UNI-N to UNI-N";
}
description
 "Container of 802.1ag CFM configurations.";
}
uses y-1731;



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description
"Container for Ethernet service OAM.";
}
description
"Grouping for Ethernet service OAM.";
}

grouping fate-sharing-group {
container groups {
leaf fate-sharing-group-size {
type uint16;
description
 "Fate sharing group size.";
}
list group {
key group-id;
leaf group-id {
 type string;
 description
   "Group-id the site network access
   is belonging to";
}
description
 "List of group-id";
}
description
"Groups the fate sharing group member
is belonging to";
}
description
"Grouping for Fate sharing group.";
}

grouping site-group {
container groups {
list group {
key group-id;
leaf group-id {
 type string;
 description
   "Group-id the site is belonging to";
}
description
 "List of group-id";
}
description
"Groups the site or site-network-access
is belonging to.";



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}
description
"Grouping definition to assign
group-ids to site or site-network-access";
}

grouping access-diversity {
container access-diversity {
if-feature site-diversity;
uses fate-sharing-group;
container constraints {
list constraint {
 key constraint-type;
 leaf constraint-type {
   type identityref {
   base placement-diversity;
   }
   description
   "Diversity constraint type.";
 }
 container target {
   choice target-flavor {
   case id {
   list group {
   key group-id;
   leaf group-id {
   type string;
   description
    "The constraint will apply
     against this particular
     group-id";
   }
    description
    "List of groups";
   }
 }
 case all-accesses {
   leaf all-other-accesses {
   type empty;
 description
   "The constraint will apply
  against all other site network
  access of this site";
   }
 }
 case all-groups {

   leaf all-other-groups {



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   type empty;
   description
   "The constraint will apply
   against all other groups the
   customer is managing";
   }
 }
   description
   "Choice for the group definition";
   }
   description
  "The constraint will apply against
  this list of groups";
 }
 description
   "List of constraints";
}
description
 "Constraints for placing this site
   network access";
}
description
"Diversity parameters.";
}
description
"This grouping defines access diversity
parameters";
}

grouping request-type-profile-grouping {
container request-type-profile {
choice request-type-choice {
case dot1q-case {
 container dot1q {
   leaf physical-if {
 type string;
 description
   "Physical interface";
   }
   leaf vlan-id {
 type uint16;
 description
   "VLAN ID";
   }
   description
  "Container for dot1q.";
 }
 description



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   "Case for dot1q";
}
case physical-case {
 leaf physical-if {
 type string;
 description
  "Physical interface";
 }
 leaf circuit-id {
   type string;
   description
 "Circuit ID";
 }
 description
   "Physical case";
}
description
 "Choice for request type";
}
description
"Container for request type profile.";
}
description
"Grouping for request type profile";
}

grouping site-attachment-bearer {
container bearer {
container requested-type {
if-feature requested-type;
leaf requested-type {
 type string;
 description
   "Type of requested bearer Ethernet, DSL,
   Wireless ..Operator specific.";
}
leaf strict {
 type boolean;
 default false;
 description
   "Define if the requested-type is a preference
   or a strict requirement.";
}
uses request-type-profile-grouping;
description
 "Container for requested type.";
}
leaf always-on {



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if-feature always-on;
type boolean;
default true;
description
 "Request for an always on access type.
  This means no Dial access type for
  example.";
}
leaf bearer-reference {
if-feature bearer-reference;
type string;
description
 "This is an internal reference for the
  service provider.";
}
description
"Bearer specific parameters.
To be augmented.";
}
description
"Grouping to define physical properties of
a site attachment.";
}

grouping vpn-attachment-grouping {
container vpn-attachment {
leaf device-id {
type string;
description
 "Device ID";
}
container management {
leaf address-family {
 type identityref {
   base address-family;
 }
 description
   "Address family used for management.";
}
leaf address {
 type inet:ip-address;
 description
   "Management address";
}
description
 "Management configuration..";
}
choice attachment-flavor {



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case vpn-flavor {
 list vpn-flavor {
 key vpn-id;
 leaf vpn-id {
   type leafref {
   path "/l2vpn-svc/vpn-services"+
   "/vpn-svc/vpn-id";
   }
   description
   "Reference to a VPN.";
 }
 leaf site-role {
   type identityref {
   base site-role;
   }
   default any-to-any-role;
   description
   "Role of the site in the IPVPN.";
 }
 description
 "List of IPVPNs attached by the Site Network Access";
}
}
case vpn-policy-id {
leaf vpn-policy-id {
type leafref {
path "/l2vpn-svc/sites/site/vpn-policies/vpn-policy/vpn-policy-id";
}
description
"Reference to a vpn policy";
}
}
mandatory true;
description
 "Choice for VPN attachment flavor.";
}
description
"Defines VPN attachment of a site.";
}
description
"Grouping for access attachment";
}

grouping site-service-basic {
container svc-input-bandwidth {
if-feature input-bw;
list input-bandwidth {
key "type";



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leaf type {
 type identityref {
   base bw-type;
 }
 description
   "Bandwidth Type";
}
leaf cos-id {
type uint8;
description
"CoS id";
}
leaf vpn-id {
 type svc-id;
 description
   "EVC ID";
}
leaf CIR {
 type uint64;
 description
   "Committed Information Rate";
}
leaf CBS {
 type uint64;
 description
   "Committed Burst Size";
}
leaf EIR {
 type uint64;
 description
   "Excess Information Rate";
}
leaf EBS {
 type uint64;
 description
   "Excess Burst Size";
}
leaf CM {
 type uint8;
 description
   "Color Mode";
}
description
 "List for input bandwidth";
}
description
"From the PE perspective, the service input
bandwidth of the connection.";



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}
container svc-output-bandwidth {
if-feature output-bw;
list output-bandwidth {
key "type";
leaf type {
 type identityref {
   base bw-type;
 }
 description
   "Bandwidth Type";
}
leaf cos-id {
type uint8;
description
"CoS id";
}
leaf vpn-id {
 type svc-id;
 description
   "EVC ID";
}
leaf CIR {
 type uint64;
 description
   "Committed Information Rate";
}
leaf CBS {
 type uint64;
 description
   "Committed Burst Size";
}
leaf EIR {
 type uint64;
 description
   "Excess Information Rate";
}
leaf EBS {
 type uint64;
 description
   "Excess Burst Size";
}
leaf CM {
 type uint8;
 description
   "Color Mode";
}
description



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 "List for output bandwidth";

}
description
"From the PE perspective, the service output
bandwidth of the connection.";
}
description
"Grouping for site service";
}

grouping flow-definition {
container match-flow {
leaf dscp {
type inet:dscp;
description
 "DSCP value.";
}
leaf dot1p {
type uint8 {
 range "0 .. 7";
}
description
 "802.1p matching.";
}
leaf pcp {
type uint8;
description
 "PCP value";
}
leaf src-mac {
type yang:mac-address;
description
"Source MAC";
}
leaf dst-mac {
type yang:mac-address;
description
"Destination MAC";
}
container composite-id {
leaf endpoint-id {
 type string;
 description
   "Endpoint ID";
}
leaf cos-label {
 type identityref {



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   base cos-id;
 }
 description
   "COS label";
}
leaf pcp {
 type uint8;
 description
   "PCP value";
}
leaf dscp {
 type inet:dscp;
 description
   "DSCP value.";
}
description
 "Container for cos color id";
}
leaf color-type {
type identityref {
 base color-type;
}
description
 "Color Types";
}
leaf-list target-sites {
type svc-id;
description
 "Identify a site as traffic destination.";
}
description
"Describe flow matching criterions.";
}
description
"Flow definition based on criteria.";
}

grouping site-service-qos-profile {
container qos {
if-feature qos;
container qos-classification-policy {
 list rule {
   key id;
   ordered-by user;
   leaf id {
   type uint16;
   description
   "ID of the rule.";



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   }
   choice match-type {
   case match-flow {
   uses flow-definition;

 }
 case match-phy-port {
   leaf match-phy-port {
   type uint16;
   description
   "Defines the physical port
   to match.";
   }
 }
 description
   "Choice for classification";
   }
   leaf target-class-id {
 type string;
 description
   "Identification of the class of service.
   This identifier is internal to the
   administration.";
 }
 description
   "List of marking rules.";
}
description
 "Need to express marking rules ...";
}
container qos-profile {
choice qos-profile {
 description
   "Choice for QoS profile.
   Can be standard profile or custom.";
 case standard {
   leaf ingress-profile {
 type string;
 description
  "Ingress QoS Profile to be used";
   }
   leaf egress-profile {
 type string;
 description
   "Egress QoS Profile to be used";
   }
 }
case custom {



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container classes {
 if-feature qos-custom;
   list class {
 key class-id;
 leaf class-id {
   type string;
   description
   "Identification of the class of
   service. This identifier is internal
   to the administration.";
  }
 leaf direction {
  type direction-type;
   description
   "Direction type";
  }
 leaf policing {
   type identityref {
   base policing;
  }
  description
 "The policing can be either one-rate,
  two-color (1R2C) or two-rate, three-color
  (2R3C)";
 }
 leaf byte-offset {
   type uint16;
   description
 "For not including extra VLAN tags in the QoS
  calculation";
 }

 leaf rate-limit {
   type uint8;
   units percent;
   description
 "To be used if class must be rate limited.
  Expressed as percentage of the svc-bw.";
 }
 leaf discard-percentage {
   type uint8;

   default 100;
   description
 "The value of the discard-percentage,
  Expressed as pecentage of the svc-bw ";
 }
 container frame-delay {



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   choice flavor {
   case lowest {
   leaf use-low-del {
   type empty;
   description
   "The traffic class should use
   the lowest delay path";
   }
 }
 case boundary {
   leaf delay-bound {
   type uint16;
   units msec;
   description
   "The traffic class should use
   a path with a defined maximum
   delay.";
   }
 }
 description
   "Delay constraint on the traffic
   class";
   }
   description
   "Delay constraint on the traffic
  class";
 }
 container frame-jitter {
   choice flavor {
   case lowest {
   leaf use-low-jit {
   type empty;
   description
   "The traffic class should use
    the lowest jitter path";
   }
 }
 case boundary {
   leaf delay-bound {
   type uint32;
   units usec;
   description
   "The traffic class should use
   a path with a defined maximum
   jitter.";
   }
 }
    description



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   "Jitter constraint on the traffic
    class";
   }
   description
   "Jitter constraint on the traffic
   class";
 }
 container frame-loss {
   leaf fr-loss-rate {
    type decimal64 {
   fraction-digits 2;
 }
   description
   "Loss constraint on the traffic class";
   }
   description
   "Container for frame loss";
 }
 container bandwidth {
  leaf guaranteed-bw-percent {
   type uint8;
  units percent;
  description
  "To be used to define the guaranteed bandwidth
  as a percentage of the available service
  bandwidth.";
   }
   leaf end-to-end {
    type empty;
    description
    "Used if the bandwidth reservation
    must be done on the MPLS network too.";
   }
   description
   "Bandwidth constraint on the traffic class.";
   }
   description
    "List of class of services.";
   }
   description
   "Container for list of class of services.";
 }
}
}
description
"Qos profile configuration.";
}
description



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"QoS configuration.";
}
description
"This grouping defines QoS parameters
for a site";
}
grouping services-grouping {
container service {
uses site-service-qos-profile;
description
"Container for service";
}
description
"Grouping for Services";
}

grouping service-grouping {
container service {
uses site-service-basic;

uses site-service-qos-profile;
description
"Container for service";
}
description
"Grouping for service.";
}

/* MAIN L2VPN SERVICE */

container l2vpn-svc {

container vpn-services {
list vpn-svc {
key "vpn-id";
leaf vpn-id {
type svc-id;
description
"Defining a service id.";
}
leaf vpn-type {
type identityref {
base service-type;
}
description
"Service type";
}
leaf customer-account-number {



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type uint32;
description
"Customer account number";
}
leaf customer-name {
type string;
description
"Customer name";
}
uses svc-type-grouping;
leaf svc-topo {
type identityref {
base vpn-topology;
}
description
"Defining service topology, such as
 any-to-any,hub-spoke, etc.";
}
uses vpn-service-cloud-access; // need fixed??

container metro-network-id {
uses inter-mkt-service;
uses intra-mkt-grouping;
description
"Container of Metro-Network ID configurations";
}
container global-l2cp-control {
if-feature L2CP-control;
leaf stp-rstp-mstp {
type control-mode;
description
  "STP/RSTP/MSTP protocol type applicable to all UNIs";
}
leaf pause {
type control-mode;
description
  "Pause protocol type applicable to all UNIs ";
}
leaf lldp {
type boolean;
description
  "LLDP protocol type applicable to all UNIs ";
}
description
"Container of L2CP control global configurations";
}
container load-balance-options {
uses load-balance-grouping;



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description
"Container for load balance options";
}
leaf service-level-mac-limit {
type string;
description
"Service-level MAC-limit (E-LAN only)";
}
uses service-protection;
uses site-service;
uses vpn-service-multicast;
uses vpn-extranet;
description
"List of vpn-svc";
}
description
"Container for VPN services.";
}

/* SITE */
container sites {
list site {
key "site-id site-type";
leaf site-id {
type string;
description
"Site id";
}
leaf site-type {
type identityref {
base site-type;
}
description
"Site type";
}
uses site-device;
uses customer-location-info;
uses site-management;
uses site-diversity;
uses site-vpn-policy ;
container signaling-options {
if-feature signaling-options;
uses signaling-options-grouping;
description
"Container for signaling option";
}
container load-balance-options {
uses load-balance-grouping;



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description
"Container for load balance options";
}
uses services-grouping;
uses B-U-M-grouping;
uses site-security;
uses operational-requirements-ops;
container site-network-accesses {
list site-network-accesse {
key "network-access-id";
leaf network-access-id {
  type string;
  description
  "Identifier of network access";
}
leaf remote-carrier-name {
  when "'../site-type' = 'enni'" {
   description
   "Site type = enni";
  }
  type string;
  description
  "Remote carrier name";
}
uses access-diversity;
uses site-attachment-bearer;
uses ethernet-connection-grouping;
uses svc-mtu-grouping;
uses availability-grouping;
uses vpn-attachment-grouping;
uses service-grouping;
uses B-U-M-grouping;
uses ethernet-svc-oam-grouping;
uses site-security;
description
  "List of ports";
}
description
"Container of port configurations";
}
description
"List of sites";
}
description
"Container of site configurations";
}

description



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"Container for L2VPN service";
}
}

<CODE ENDS>

9.  Security Considerations

   The YANG modules defined in this document MAY be accessed via the
   RESTCONF protocol [RFC8040] or NETCONF protocol ([RFC6241]).  The
   lowest RESTCONF or NETCONF layer requires that the transport-layer
   protocol provides both data integrity and confidentiality, see
   Section 2 in [RFC8040] and [RFC6241].  The client MUST carefully
   examine the certificate presented by the server to determine if it
   meets the client's expectations, and the server MUST authenticate
   client access to any protected resource.  The client identity derived
   from the authentication mechanism used is subject to the NETCONF
   Access Control Module (NACM) ([RFC6536]).  Other protocols to access
   this YANG module are also required to support the similar mechanism.

   The data nodes defined in the "ietf-l2vpn-svc" YANG module MUST be
   carefully created/read/updated/deleted.  The entries in the lists
   below include customer proprietary or confidential information,
   therefore only authorized clients MUST access the information and the
   other clients MUST NOT be able to access to the information.

   o  /l2vpn-svc/customer-info/customer-info

   o  /l2vpn-svc/vpn-services/vpn-svc

   o  /l2vpn-svc/sites/site

10.  Acknowledgements

   Thanks to Qin Wu and Adrian Farrel for facilitating work on the
   initial revisions of this document.  Thanks to Zonghe Huang, Wei Deng
   and Xiaoling Song to help review this draft.

   This document has drawn on the work of the L3SM Working Group
   expressed in [RFC8049].

11.  IANA Considerations

   IANA is requested to assign a new URI from the IETF XML registry
   ([RFC3688]).  The following URI is suggested:






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       URI: urn:ietf:params:xml:ns:yang:ietf-l2vpn-svc
       Registrant Contact: L2SM WG
       XML: N/A, the requested URI is an XML namespace


   This document also requests a new YANG module name in the YANG Module
   Names registry ([RFC6020]) with the following suggestion:


       name: ietf-l2vpn-svc
       namespace: urn:ietf:params:xml:ns:yang:ietf-l2vpn-svc
       prefix: l2vpn-svc
       reference: RFC XXXX


12.  References

12.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.

   [RFC4448]  Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
              "Encapsulation Methods for Transport of Ethernet over MPLS
              Networks", RFC 4448, DOI 10.17487/RFC4448, April 2006,
              <http://www.rfc-editor.org/info/rfc4448>.

   [RFC4761]  Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
              LAN Service (VPLS) Using BGP for Auto-Discovery and
              Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007,
              <http://www.rfc-editor.org/info/rfc4761>.

   [RFC4762]  Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private
              LAN Service (VPLS) Using Label Distribution Protocol (LDP)
              Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
              <http://www.rfc-editor.org/info/rfc4762>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://www.rfc-editor.org/info/rfc6020>.




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   [RFC6073]  Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
              Aissaoui, "Segmented Pseudowire", RFC 6073,
              DOI 10.17487/RFC6073, January 2011,
              <http://www.rfc-editor.org/info/rfc6073>.

   [RFC6074]  Rosen, E., Davie, B., Radoaca, V., and W. Luo,
              "Provisioning, Auto-Discovery, and Signaling in Layer 2
              Virtual Private Networks (L2VPNs)", RFC 6074,
              DOI 10.17487/RFC6074, January 2011,
              <http://www.rfc-editor.org/info/rfc6074>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <http://www.rfc-editor.org/info/rfc6991>.

   [RFC7224]  Bjorklund, M., "IANA Interface Type YANG Module",
              RFC 7224, DOI 10.17487/RFC7224, May 2014,
              <http://www.rfc-editor.org/info/rfc7224>.

   [RFC7432]  Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
              Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
              Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
              2015, <http://www.rfc-editor.org/info/rfc7432>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <http://www.rfc-editor.org/info/rfc8040>.

   [RFC8049]  Litkowski, S., Tomotaki, L., and K. Ogaki, "YANG Data
              Model for L3VPN Service Delivery", RFC 8049,
              DOI 10.17487/RFC8049, February 2017,
              <http://www.rfc-editor.org/info/rfc8049>.

12.2.  Informative References







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   [I-D.ietf-bess-evpn-yang]
              Brissette, P., Sajassi, A., Shah, H., Li, Z.,
              Tiruveedhula, K., Hussain, I., and J. Rabadan, "Yang Data
              Model for EVPN", draft-ietf-bess-evpn-yang-02 (work in
              progress), March 2017.

   [I-D.ietf-bess-l2vpn-yang]
              Shah, H., Brissette, P., Chen, I., Hussain, I., Wen, B.,
              and K. Tiruveedhula, "YANG Data Model for MPLS-based
              L2VPN", draft-ietf-bess-l2vpn-yang-06 (work in progress),
              June 2017.

   [I-D.ietf-opsawg-service-model-explained]
              Wu, Q., LIU, W., and A. Farrel, "Service Models
              Explained", draft-ietf-opsawg-service-model-explained-01
              (work in progress), June 2017.

   [IEEE-802-1ag]
              IEEE, "802.1ag - Connectivity Fault Management", December
              2007.

   [ITU-T-Y-1731]
              ITU-T, "Recommendation Y.1731 - OAM functions and
              mechanisms for Ethernet based networks", February 2008.

   [MEF-23-2]
              MEF Forum, "Implementation Agreement MEF 23.2 : Carrier
              Ethernet Class of Service - Phase 3", August 2016.

   [RFC6624]  Kompella, K., Kothari, B., and R. Cherukuri, "Layer 2
              Virtual Private Networks Using BGP for Auto-Discovery and
              Signaling", RFC 6624, DOI 10.17487/RFC6624, May 2012,
              <http://www.rfc-editor.org/info/rfc6624>.

Appendix A.  Changes Log

   Changes in v-(01) include:

   o  Reference Update.

   o  Fix figure in section 3.3 and section 3.4

   o  Consider VPWS, VPLS, EVPN as basic service and view EVC related
      service as additional service.

   o  Model structure change, move two customer information related
      parameter into VPN Services container, remove 'customer-info
      'container



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   o  Redefine vpn-type to cover VPWS, VPLS, EVPN service;

   o  Consolidate EVC and OVC container, make them optional since for
      some L2VPN service such as EVPN sevice, OVC, EVC are not needed.

   o  Add service and security filter under sites container and change
      "ports" into "site-network-accesses" to get consistent with L3SM
      and also make it generalized.

   o  Fixed usage examples in the l2sm model draft.

   Changes in v-(02) include:

   o  Fix figure 3 and figure 4 in section 3.4 to apply IEEE802.3 on the
      segment between C and CE and apply IEEE802.1Q on the segment
      between CE and PE.

   o  Update Signaling Option section and add L2TP support and classify
      the signaling option type into BGP-L2VPN, BGP-EVPN, LDP-PWE, L2TP-
      PW.

   o  Add Multicast Support in section 5.2.13, section 5.10.3 and move
      the text in BUM Storm Control section into section 5.10.3.

   o  Add new section 5.3.1, section 5.4, section 5.5, section 5.6,
      section 5.7, section 5.8, section 5.11to explain the usage of
      constraint parameters and service placement related parameters.

   o  Add new section 5.1 and 5.14 to allow augmentation and external ID
      References.

   o  Add new section to discuss inter-AS support and inter-provider
      support with NNI and EVC, OVC.

   o  Update Service Section 5.10 and define four type for svc-input-
      bandwidth and svc-output-bandwidth and add guaranteed-bw-percent
      parameter and related description.

   o  Add extranet VPN support.

   o  Remove duplicated parameters from cloud access.

   o  Move L2CP control plane protocol parameters under connection.

   o  Update section 5.3.3.2 to address loop avoidance issue and divide
      section 5.3.3.2 into Physical interface section, LAG interface
      section and Addressing Section.




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   o  Reference Update.

Appendix B.  Open Issues

   o Do we need to support L2VPN Interworking with ATMoMPLS,PPPoMPLS,
   FroMPLS?

   o Need to understand relationship between member link name under LAG-
   interface and network-access-id.

   o Need to Revisit Signaling Option to see how it is applied.

Authors' Addresses

   Bin Wen
   Comcast

   Email: bin_wen@comcast.com


   Giuseppe Fioccola (editor)
   Telecom Italia

   Email: giuseppe.fioccola@telecomitalia.it


   Chongfeng Xie
   China Telecom

   Email: xiechf@ctbri.com.cn


   Luay Jalil
   Verizon

   Email: luay.jalil@verizon.com















Wen, et al.              Expires January 4, 2018              [Page 160]


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