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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: July 19, 2018                                    Telecom Italia
                                                                  C. Xie
                                                           China Telecom
                                                                L. Jalil
                                                                 Verizon
                                                        January 15, 2018


              A YANG Data Model for L2VPN Service Delivery
                 draft-ietf-l2sm-l2vpn-service-model-05

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", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174]when, and only when, they appear in all
   capitals, as shown here.

Status of This Memo

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





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Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Tree diagram  . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  The Layer 2 VPN Service Model . . . . . . . . . . . . . . . .   7
     3.1.  Layer 2 VPN Service Types . . . . . . . . . . . . . . . .   7
     3.2.  Layer 2 VPN Physical Network Topology . . . . . . . . . .   8
   4.  Service Data Model Usage  . . . . . . . . . . . . . . . . . .   9
   5.  Design of the Data Model  . . . . . . . . . . . . . . . . . .  11
     5.1.  Features and Augmentation . . . . . . . . . . . . . . . .  20
     5.2.  VPN Service Overview  . . . . . . . . . . . . . . . . . .  21
       5.2.1.  VPN Service Type  . . . . . . . . . . . . . . . . . .  21
       5.2.2.  VPN Service Topology  . . . . . . . . . . . . . . . .  22
         5.2.2.1.  Route Target Allocation . . . . . . . . . . . . .  22
         5.2.2.2.  Any-to-Any  . . . . . . . . . . . . . . . . . . .  22
         5.2.2.3.  Hub and Spoke . . . . . . . . . . . . . . . . . .  23
         5.2.2.4.  Hub and Spoke Disjoint  . . . . . . . . . . . . .  23
       5.2.3.  Cloud Access  . . . . . . . . . . . . . . . . . . . .  24
       5.2.4.  Extranet VPNs . . . . . . . . . . . . . . . . . . . .  26



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       5.2.5.  Frame Delivery Service  . . . . . . . . . . . . . . .  27
     5.3.  Site Overview . . . . . . . . . . . . . . . . . . . . . .  28
       5.3.1.  Devices and Locations . . . . . . . . . . . . . . . .  30
       5.3.2.  Site Network Accesses . . . . . . . . . . . . . . . .  31
         5.3.2.1.  Bearer  . . . . . . . . . . . . . . . . . . . . .  31
         5.3.2.2.  Connection  . . . . . . . . . . . . . . . . . . .  32
     5.4.  Site Role . . . . . . . . . . . . . . . . . . . . . . . .  36
     5.5.  Site Belonging to Multiple VPNs . . . . . . . . . . . . .  36
       5.5.1.  Site VPN Flavor . . . . . . . . . . . . . . . . . . .  36
         5.5.1.1.  Single VPN Attachment: site-vpn-flavor-single . .  37
         5.5.1.2.  MultiVPN Attachment: site-vpn-flavor-multi  . . .  37
         5.5.1.3.  NNI: site-vpn-flavor-nni  . . . . . . . . . . . .  38
         5.5.1.4.  E2E: site-vpn-flavor-e2e  . . . . . . . . . . . .  39
       5.5.2.  Attaching a Site to a VPN . . . . . . . . . . . . . .  39
         5.5.2.1.  Referencing a VPN . . . . . . . . . . . . . . . .  39
         5.5.2.2.  VPN Policy  . . . . . . . . . . . . . . . . . . .  40
     5.6.  Deciding Where to Connect the Site  . . . . . . . . . . .  43
       5.6.1.  Constraint: Device  . . . . . . . . . . . . . . . . .  44
       5.6.2.  Constraint/Parameter: Site Location . . . . . . . . .  44
       5.6.3.  Constraint/Parameter: Access Type . . . . . . . . . .  46
       5.6.4.  Constraint: Access Diversity  . . . . . . . . . . . .  47
     5.7.  Route Distinguisher and Network Instance Allocation . . .  48
     5.8.  Site Network Access Availability  . . . . . . . . . . . .  49
     5.9.  SVC MTU . . . . . . . . . . . . . . . . . . . . . . . . .  50
     5.10. Service . . . . . . . . . . . . . . . . . . . . . . . . .  50
       5.10.1.  Bandwidth  . . . . . . . . . . . . . . . . . . . . .  50
       5.10.2.  QoS  . . . . . . . . . . . . . . . . . . . . . . . .  51
         5.10.2.1.  QoS Classification . . . . . . . . . . . . . . .  52
         5.10.2.2.  QoS Profile  . . . . . . . . . . . . . . . . . .  52
       5.10.3.  Broadcast Multicast Unknow Unicast Support . . . . .  54
     5.11. Site Management . . . . . . . . . . . . . . . . . . . . .  54
     5.12. MAC Loop Protection . . . . . . . . . . . . . . . . . . .  55
     5.13. MAC Address Limit . . . . . . . . . . . . . . . . . . . .  55
     5.14. Enhanced VPN Features . . . . . . . . . . . . . . . . . .  56
       5.14.1.  Carriers' Carriers . . . . . . . . . . . . . . . . .  56
     5.15. External ID References  . . . . . . . . . . . . . . . . .  57
     5.16. Defining NNIs and Inter-AS support  . . . . . . . . . . .  57
       5.16.1.  Defining an NNI with the Option A Flavor . . . . . .  59
       5.16.2.  Defining an NNI with the Option B Flavor . . . . . .  62
       5.16.3.  Defining an NNI with the Option C Flavor . . . . . .  64
     5.17. Applicability of L2SM model in Inter-Provider and Inter-
           Domain Orchestration  . . . . . . . . . . . . . . . . . .  65
   6.  Interaction with Other YANG Modules . . . . . . . . . . . . .  67
   7.  Service Model Usage Example . . . . . . . . . . . . . . . . .  68
   8.  YANG Module . . . . . . . . . . . . . . . . . . . . . . . . .  73
   9.  Security Considerations . . . . . . . . . . . . . . . . . . . 140
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 141
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 142



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   12. References  . . . . . . . . . . . . . . . . . . . . . . . . . 142
     12.1.  Normative References . . . . . . . . . . . . . . . . . . 142
     12.2.  Informative References . . . . . . . . . . . . . . . . . 144
   Appendix A.  Changes Log  . . . . . . . . . . . . . . . . . . . . 145
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 149

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
   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] and [RFC8199].  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.

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:




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   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.

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.



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   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.

   MAC-VRF:  A Virtual Routing and Forwarding table for Media Access
      Control (MAC) addresses on a PE.  It is sometime also referred to
      VSI.

   UNI:  The physical demarcation point between the responsibility of
      Customer and the responsibility of Provider.

   NNI:  a reference point representing the boundary between two
      Networks that are operated as separate administrative domains.
      The two networks may belong to the same provider or two different
      providers.

   This document uses the following abbreviations:

   BSS:  Business Support System

   B-U-M:  Broadcast-UnknownUnicast-Multicast

   CoS:  Class of Service

   LAG:  Link Aggregation Group



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   LLDP:  Link Level Discovery Protocol

   OAM:  Operations, Administration, and Maintenance

   OSS:  Operations Support System

   PDU:  Protocol Data Unit

   QoS:  Quality of Service

   VSI:  Virtual Switching Instance

   UNI:  User to Network Interface

   NNI:  Network 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], EVPN as described in [RFC7432].

3.1.  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) that use LDP-
      signaled Psedowires or L2TP-signaled Psedowires [RFC6074];

   o  Multipoint Virtual Private LAN services (VPLS) that use LDP-
      signaled Pseudowires or L2TP-signaled Psedowires [RFC6074];

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





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   o  IP-Only LAN-Like Service (IPLS) which is a functional subset of
      the VPLS service [RFC4664] ;

   o  BGP MPLS-based Ethernet VPN Servie [RFC7432][RFC7209];

   o  Ethernet VPN VPWS specified in [RFC8214] and [RFC7432];

3.2.  Layer 2 VPN Physical Network Topology

   Figure 1depicts a typical service provider's physical network
   topology.  Most service providers have deployed an IP, MPLS, or
   Segment Routing (SR) multi-service core infrastructure.  Ingress
   Layer 2 service frames will be mapped to either Ethernet Pseudowire
   (PWE) or VxLAN PE-to-PE tunnel.  The details of these tunneling
   mechanism are at the provider's discretion and not part of the L2SM.

   A L2VPN 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 layer 2 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 between CE and PE will be discussed in the L2SM
   model.

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

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



















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            Site A  |                          |Site B
    ---     ----     |        VXLAN/PW          |               ---
   |   |   |    |    |<------------------------>|              |   |
   | 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.


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

                   Figure 2: Customer View of the L2VPN

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.



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   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.

   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 3 and
   described in more detail in [I-D.ietf-opsawg-service-model-explained]
   and [RFC8199].  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].
































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

         ++++++++   Bearer    ++++++++           ++++++++      ++++++++
         + CE A + ----------- + PE A +           + PE B + ---- + CE B +
         ++++++++  Connection ++++++++           ++++++++      ++++++++

                    Site A                               Site B

     Figure 3: Reference Architecture for the Use of the L2VPN Service
                                   Model

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
   customer.A circuit represents an end-to-end connection between two or
   more locations of Customers.





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   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 5.3.2) and
   there may be multiple network accesses 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.

   An end to end Multi-segment connectivity can be realized using
   combination of Per Site connectivity and Per Segment connectivity at
   different segments.

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

module: ietf-l2vpn-svc
   +--rw l2vpn-svc
      +--rw vpn-profiles
      |  +--rw valid-provider-identifiers
      |     +--rw cloud-identifier* [id] {cloud-access}?
      |     |  +--rw id    string
      |     +--rw qos-profile-identifier* [id]
      |        +--rw id    string
      +--rw vpn-services
      |  +--rw vpn-service* [vpn-id]
      |     +--rw vpn-id                      svc-id
      |     +--rw svc-type?                   identityref
      |     +--rw customer-name?              string
      |     +--rw svc-topo?                   identityref
      |     +--rw cloud-accesses {cloud-access}?
      |     |  +--rw cloud-access* [cloud-identifier]
      |     |     +--rw cloud-identifier      leafref
      |     |     +--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*



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                                -> /l2vpn-svc/sites/site/site-id
      |     +--rw frame-delivery {frame-delivery}?
      |     |  +--rw customer-tree-flavors
      |     |  |  +--rw tree-flavor*   identityref
      |     |  +--rw bum-frame-delivery
      |     |  |  +--rw bum-frame-delivery* [frame-type]
      |     |  |     +--rw frame-type       identityref
      |     |  |     +--rw delivery-mode?   identityref
      |     |  +--rw multicast-gp-port-mapping    identityref
      |     +--rw extranet-vpns {extranet-vpn}?
      |     |  +--rw extranet-vpn* [vpn-id]
      |     |     +--rw vpn-id              svc-id
      |     |     +--rw local-sites-role?   identityref
      |     +--rw ce-vlan-preservation?       boolean
      |     +--rw ce-vlan-cos-perservation?   boolean
      |     +--rw carrierscarrier?            boolean {carrierscarrier}?
      +--rw sites
         +--rw site* [site-id]
            +--rw site-id                                string
            +--rw site-vpn-flavor?                       identityref
            +--rw devices
            |  +--rw device* [device-id]
            |     +--rw device-id     string
            |     +--rw location
                          -> ../../../locations/location/location-id
            |     +--rw management
            |        +--rw management-transport?   identityref
            |        +--rw address?                inet:ip-address
            +--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 filters



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            |        |  +--rw filter* [type]
            |        |     +--rw type       identityref
            |        |     +--rw lan-tag*   uint32 {lan-tag}?
            |        +--rw vpn* [vpn-id]
            |           +--rw vpn-id       leafref
            |           +--rw site-role?   identityref
            +--rw service
            |  +--rw svc-bandwidth {input-bw}?
            |  |  +--rw bandwidth* [direction type]
            |  |     +--rw direction    identityref
            |  |     +--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 pir?         uint64
            |  |     +--rw pbs?         uint64
            |  +--rw svc-mtu            uint16
            |  +--rw qos {qos}?
            |  |  +--rw qos-classification-policy
            |  |  |  +--rw rule* [id]
            |  |  |     +--rw id                   string
            |  |  |     +--rw (match-type)?
            |  |  |     |  +--:(match-flow)
            |  |  |     |  |  +--rw match-flow
            |  |  |     |  |     +--rw dscp?           inet:dscp
            |  |  |     |  |     +--rw dot1q?          uint16
            |  |  |     |  |     +--rw pcp?            uint8
            |  |  |     |  |     +--rw src-mac?        yang:mac-address
            |  |  |     |  |     +--rw dst-mac?        yang:mac-address
            |  |  |     |  |     +--rw color-type?     identityref
            |  |  |     |  |     +--rw target-sites*   svc-id {target-sites}?
            |  |  |     |  |     +--rw any?            empty
            |  |  |     |  |     +--rw vpn-id?         svc-id
            |  |  |     |  +--:(match-phy-port)
            |  |  |     |  |  +--rw match-phy-port?      uint16
            |  |  |     |  +--:(match-application)
            |  |  |     |     +--rw match-application?   identityref
            |  |  |     +--rw target-class-id?     string
            |  |  +--rw qos-profile
            |  |     +--rw (qos-profile)?
            |  |        +--:(standard)
            |  |        |  +--rw profile?   leafref
            |  |        +--:(custom)
            |  |           +--rw classes {qos-custom}?
            |  |              +--rw class* [class-id]



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            |  |                 +--rw class-id        string
            |  |                 +--rw direction?      identityref
            |  |                 +--rw policing?       identityref
            |  |                 +--rw byte-offset?    uint16
            |  |                 +--rw frame-delay
            |  |                 |  +--rw (flavor)?
            |  |                 |     +--:(lowest)
            |  |                 |     |  +--rw use-lowest-latency?   empty
            |  |                 |     +--:(boundary)
            |  |                 |        +--rw delay-bound?          uint16
            |  |                 +--rw frame-jitter
            |  |                 |  +--rw (flavor)?
            |  |                 |     +--:(lowest)
            |  |                 |     |  +--rw use-lowest-jitter?   empty
            |  |                 |     +--:(boundary)
            |  |                 |        +--rw delay-bound?         uint32
            |  |                 +--rw frame-loss
            |  |                 |  +--rw fr-loss-rate?   decimal64
            |  |                 +--rw bandwidth
            |  |                    +--rw guaranteed-bw-percent    decimal64
            |  |                    +--rw end-to-end?              empty
            |  +--rw carrierscarrier {carrierscarrier}?
            |     +--rw signalling-type?   identityref
            +--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 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
            +--ro actual-site-start?                     yang:date-and-time
            +--ro actual-site-stop?                      yang:date-and-time
            +--rw bundling-type?                         identityref
            +--rw default-ce-vlan-id?                    uint32
            +--rw site-network-accesses
               +--rw site-network-access* [network-access-id]
                  +--rw network-access-id                      string



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                  +--rw remote-carrier-name?                   string
                  +--rw site-network-access-type?              identityref
                  +--rw (location-flavor)
                  |  +--:(location)
                  |  |  +--rw location-reference?             leafref
                  |  +--:(device)
                  |     +--rw device-reference?
                                -> ../../../devices/device/device-id
                  +--rw access-diversity {site-diversity}?
                  |  +--rw groups
                  |  |  +--rw fate-sharing-group-size?   uint16
                  |  |  +--rw group-color?               string
                  |  |  +--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 always-on?          boolean {always-on}?
                  |  +--rw bearer-reference?   string {bearer-reference}?
                  +--rw connection
                  |  +--rw encapsulation-type?    identityref
                  |  +--rw eth-inf-type?          identityref
                  |  +--rw tagged-interface
                  |  |  +--rw tagged-inf-type?     identityref
                  |  |  +--rw dot1q-vlan-tagged {dot1q}?
                  |  |  |  +--rw tag-type?   identityref
                  |  |  |  +--rw cvlan-id?   uint16
                  |  |  +--rw priority-tagged
                  |  |  |  +--rw tag-type?   identityref
                  |  |  +--rw qinq {qinq}?
                  |  |  |  +--rw tag-type?   identityref
                  |  |  |  +--rw svlan-id?   uint16
                  |  |  |  +--rw cvlan-id?   uint16
                  |  |  +--rw qinany {qinany}?
                  |  |  |  +--rw tag-type?   identityref



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                  |  |  |  +--rw svlan-id?   uint16
                  |  |  +--rw vxlan {vxlan}?
                  |  |     +--rw vni-id?      uint32
                  |  |     +--rw peer-mode?   identityref
                  |  |     +--rw peer-list* [peer-ip]
                  |  |        +--rw peer-ip    inet:ip-address
                  |  +--rw untagged-interface
                  |  |  +--rw ifindex?               uint32
                  |  |  +--rw port-speed?            uint32
                  |  |  +--rw mode?                  neg-mode
                  |  |  +--rw phy-mtu?               uint32
                  |  |  +--rw flow-control?          string
                  |  |  +--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-ifindex]
                  |  |     +--rw lag-ifindex    uint32
                  |  |     +--rw lacp
                  |  |        +--rw lacp-state?         boolean
                  |  |        +--rw lacp-mode?          boolean
                  |  |        +--rw lacp-speed?         uint32
                  |  |        +--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
                  |  |        +--rw member-link-list
                  |  |        |  +--rw member-link* [name]
                  |  |        |     +--rw name                string
                  |  |        |     +--rw port-speed?         uint32
                  |  |        |     +--rw mode?               neg-mode
                  |  |        |     +--rw link-mtu?           uint32
                  |  |        |     +--rw oam-802.3ah-link {oam-3ah}?
                  |  |        |        +--rw enable?   boolean
                  |  |        +--rw flow-control?       string
                  |  |        +--rw lldp?               boolean
                  |  +--rw cvlan-id-to-svc-map* [svc-id]
                  |  |  +--rw svc-id



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                                -> /l2vpn-svc/vpn-services/vpn-service/vpn-id
                  |  |  +--rw cvlan-id* [vid]
                  |  |     +--rw vid    uint16
                  |  +--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 oam
                  |     +--rw md-name?        string
                  |     +--rw md-level?       uint8
                  |     +--rw cfm-802.1-ag* [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 availability
                  |  +--rw access-priority?   uint32
                  |  +--rw (redundancy-mode)?
                  |     +--:(single-active)
                  |     |  +--rw single-active?     boolean



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                  |     +--:(all-active)
                  |        +--rw all-active?        boolean
                  +--rw vpn-attachment
                  |  +--rw attachment-device-id?   string
                  |  +--rw management
                  |  |  +--rw address-family?   identityref
                  |  |  +--rw address           inet:ip-address
                  |  +--rw (attachment-flavor)
                  |     +--:(vpn-policy-id)
                  |     |  +--rw vpn-policy-id?          leafref
                  |     +--:(vpn-id)
                  |     |  +--rw vpn-id?                 leafref
                  |     |  +--rw site-role?              identityref
                  +--rw service
                  |  +--rw qos {qos}?
                  |  |  +--rw qos-classification-policy
                  |  |  |  +--rw rule* [id]
                  |  |  |     +--rw id                   string
                  |  |  |     +--rw (match-type)?
                  |  |  |     |  +--:(match-flow)
                  |  |  |     |  |  +--rw match-flow
                  |  |  |     |  |     +--rw dscp?           inet:dscp
                  |  |  |     |  |     +--rw dot1q?          uint16
                  |  |  |     |  |     +--rw pcp?            uint8
                  |  |  |     |  |     +--rw src-mac?        yang:mac-address
                  |  |  |     |  |     +--rw dst-mac?        yang:mac-address
                  |  |  |     |  |     +--rw color-type?     identityref
                  |  |  |     |  |     +--rw target-sites*   svc-id {target-sites}?
                  |  |  |     |  |     +--rw any?            empty
                  |  |  |     |  |     +--rw vpn-id?         svc-id
                  |  |  |     |  +--:(match-phy-port)
                  |  |  |     |  |  +--rw match-phy-port?      uint16
                  |  |  |     |  +--:(match-application)
                  |  |  |     |     +--rw match-application?   identityref
                  |  |  |     +--rw target-class-id?     string
                  |  |  +--rw qos-profile
                  |  |     +--rw (qos-profile)?
                  |  |        +--:(standard)
                  |  |        |  +--rw profile?   -> /l2vpn-svc/vpn-profiles/valid-provider-identifiers/qos-profile-identifier/id
                  |  |        +--:(custom)
                  |  |           +--rw classes {qos-custom}?
                  |  |              +--rw class* [class-id]
                  |  |                 +--rw class-id        string
                  |  |                 +--rw direction?      identityref
                  |  |                 +--rw policing?       identityref
                  |  |                 +--rw byte-offset?    uint16
                  |  |                 +--rw frame-delay
                  |  |                 |  +--rw (flavor)?



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                  |  |                 |     +--:(lowest)
                  |  |                 |     |  +--rw use-lowest-latency?   empty
                  |  |                 |     +--:(boundary)
                  |  |                 |        +--rw delay-bound?          uint16
                  |  |                 +--rw frame-jitter
                  |  |                 |  +--rw (flavor)?
                  |  |                 |     +--:(lowest)
                  |  |                 |     |  +--rw use-lowest-jitter?   empty
                  |  |                 |     +--:(boundary)
                  |  |                 |        +--rw delay-bound?         uint32
                  |  |                 +--rw frame-loss
                  |  |                 |  +--rw fr-loss-rate?   decimal64
                  |  |                 +--rw bandwidth
                  |  |                    +--rw guaranteed-bw-percent    decimal64
                  |  |                    +--rw end-to-end?              empty
                  |  +--rw carrierscarrier {carrierscarrier}?
                  |     +--rw signalling-type?   identityref
                  +--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 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 mac-num-limit?   uint16
                     +--rw time-interval?   uint32
                     +--rw action?          identityref

                                 Figure 4

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 (Section 5.3.3.2) proposed to the customer may
   also be enabled through features.  This model also proposes some



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   features for options that are more advanced, such as support for
   extranet VPNs (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.  For
   example, this model proposes VXLAN [RFC7348] for Ethernet packet
   Encapsulation; if VXLAN Encapsulation do not fulfill all
   requirements, new options can be added through augmentation.

5.2.  VPN Service Overview

   A vpn-service list item contains generic information 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 customer.

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

    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.

   Frame Delivery Service (frame-delivery):  Provide frame Delivery
      support for L2VPN,e.g.,multicast delivery, unicast delivery,
      broadcast delivery.

   Extranet VPN (extranet-vpns):  Allow a particular VPN needs access to
      resources located in another VPN.

5.2.1.  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) connecting two
      customer Sites;



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   o  Point-to-point or point-to-multipoint Virtual Private Wire
      Services (VPWS) connecting a set of customer sites [RFC8214];

   o  Multipoint Virtual Private LAN services (VPLS) connecting a set of
      customer sites;

   o  Multipoint Virtual Private LAN services (VPLS) connecting one or
      more root sites and a set of leave sites, but preventing inter-
      leaf sites communication.

   o  EVPN Service connecting a set of customer sites.

   o  Ethernet VPN VPWS between two customer sites or a set of customer
      sites specified in [RFC8214] and [RFC7432];

   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.  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),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.

5.2.2.1.  Route Target Allocation

   A Layer 2 PE-based VPN (such as VPLS based VPN or EVPN that uses BGP
   as signaling protocol ) can be built using route targets (RTs) as
   described in [RFC4364][RFC7432].  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].

5.2.2.2.  Any-to-Any

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

                      Any-to-Any VPN Service Topology



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   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 MAC-VRF and RTs on the
   appropriate PEs.  In the any-to-any case, a single RT is generally
   required, and every MAC-VRF imports and exports this RT.

5.2.2.3.  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 a
   Hub and Spoke L2 VPN service request through this model is expected
   to assign and then configure the MAC-VRF 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 MAC-VRF 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 the
   Hub RT to allow Hub-to-Hub communication.  A Spoke MAC-VRF that
   connects Spoke sites will export Spoke routes with the Spoke RT and
   will import Hub routes through the Hub RT.

5.2.2.4.  Hub and Spoke Disjoint

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

                  Hub and Spoke Disjoint VPN Service Topology

   In the Hub and Spoke disjoint VPN service topology, all Spoke sites
   can communicate only with Hub sites but not with each other, and Hubs
   cannot communicate with each other.  The management system that owns
   a Hub and Spoke Disjoint L2VPN service request through this model is



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   expected to assign and then configure the VRF and RTs on the
   appropriate PEs.  In the Hub-and-Spoke case, two RTs are required
   (one RT for Hub routes and one RT for Spoke routes).  A Hub VRF that
   connects Hub sites will export Hub routes with the Hub RT and will
   import Spoke routes through the Spoke RT.  A Spoke VRF that connects
   Spoke sites will export Spoke routes with the Spoke RT and will
   import Hub routes through the Hub RT.

   The management system MUST take into account constraints on Hub-and-
   Spoke connections, as in the previous case.

   Hub and Spoke disjoint can also be seen as multiple Hub-and-Spoke
   VPNs (one per Hub) that share a common set of Spoke sites.

5.2.3.  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 container as
   described in Section 5.3 with the use consistent with sites of type
   NNI.

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

   By default, all sites in the L2VPN 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.













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                        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.

      <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.




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      <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>

5.2.4.  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
   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.




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   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.

5.2.5.  Frame Delivery Service

   If Frame Delivery Service support is required for an L2VPN, some
   global frame delivery 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 frame 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
   (and can be augmented).  Multiple flavors of trees can be supported
   simultaneously.









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

   Multicast 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.  Each site is associated with one or more location.

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




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   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.

   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.

   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.




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   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.

          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.





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

5.3.2.  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.

   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.

   This site-network-access type 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.

5.3.2.1.  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.




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5.3.2.2.  Connection

   The "connection" container defines the layer 2 protocol parameters of
   the attachment(e.g.,vlan-id or circuit-id) 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.

   "encapsulation-type" is for user to select between Ethernet
   encapsulation (port-based) or Ethernet VLAN encapsulation (VLAN-
   based).  All allowed Ethernet interface types of service frames can
   be listed under "ether-inf-type", e.g., untagged interface, tagged
   interface, LAG interface

   Corresponding to "ether-inf-type",the connection container also
   presents three sets of link attributes: untagged interface,tagged
   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.

5.3.2.2.1.  Untagged Interface

   For each untagged interface (untagged-interface), there are basic
   configuration parameters like interface index and speed, interface
   MTU, auto-negotiation and flow-control settings, etc.  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.

5.3.2.2.2.  Tagged Interface

   If the tagged service is enabled on a logical unit on the connection
   at the interface, "encapsulation-type ", should be specified as
   Ethernet VLAN ecapsulation(VLAN-based) or VXLAN encapsulation and
   "eth-inf-type" should be specified as tagged interface.

   In addition, "tagged-interface-type" should be specified under
   "tagged-interface" container to determines how tagging needs to be
   done.  The current model proposed 5 ways to perform VLAN tagging:

   o  priority-tagged: Service providers encapsulate and tag packets
      between CE and PE with the frame priority level.



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   o  dot1q-vlan-tagged: Service providers encapsulate packets between
      CE and PE with one or a set of customer VLAN IDs C-VLANs)

   o  qinq: service providers encapsulate packets that enter the
      service-provider network with multiple customer VLAN IDs (C-VLANs)
      and a single VLAN tag with a single service provider VLAN
      (S-VLAN).

   o  qinany: service providers encapsulate packets that enter the
      service-provider network with unknown C-VLAN and a single VLAN tag
      with a single service provider VLAN (S-VLAN).

   o  vxlan: service providers encapsulate packets that enter the
      service-provider network with VNI and peer list.

   The overall S-tag for the Ethernet circuit and C-tag to SVC mapping,
   if applicable, has been placed in the service container.  For qinq an
   qinany options, the S-tag under "qinq" and "qinany" 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.

5.3.2.2.3.  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
   whether it will be running in active versus passive mode, plus the
   time interval and priority level of the LACP PDU.  The customer 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



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   independent UDP sessions to monitor the status of each member link.
   Customer 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.

5.3.2.2.4.  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
   L2VPN services based upon pre-arranged customer VLAN to SVC mapping.
   Multiple customer VLANs can be bundled across the same SVC.  The
   bundling type will determine how a group of CVLAN is bundled into one
   VPN service(i.e.,VLAN-Bundling).

   "cvlan-id-to-svc-map", when applicable, contains the list of customer
   vlans that are mapped to the same service.  In most cases, this will
   be the VLAN access-list for the inner 802.1q tag (the C-tag).

   An VPN Service can be set to preserve the CE-VLAN ID and CE-VLAN CoS
   from source site to destination site.  This is required when the
   customer is using the VLAN header information between its locations
   of two sites.  CE-VLAN ID Preservation and CE-VLAN CoS Preservation
   are applied on each site-network-access within sites.  Preservation
   means that the value of CE-VLAN ID and/or CE-VLAN CoS at source site
   must be equal to the value at a destination site belonging to the
   same L2VPN Service.

   If All-to-One bundling is Enabled (i.e., bundling type is set to all-
   to-one bundling), 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.

5.3.2.2.5.  L2CP Control Support

   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




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   protocols (typically in the case where a CE is a router and is not
   aware of Layer-2 details).

   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
   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.

5.3.2.2.6.  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 SP network, particularly in the area of service
   availability and Mean Time To Repair (MTTR).  Ethernet Service OAM in
   the L2SM model 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 site network access
   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
   with 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 customer network, solely within the SP
   network, interact between the customer-to-provider or provider-to-
   provider edge equipment, or tunnel over another SP network.




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   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 "site-network-access"
   currently presents CFM maintenance association (MA): i.e.,DOWN MEP
   for UNI 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, 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 "site-network-access" 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.

5.4.  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-vpn-flavor"
   defines the way the VPN multiplexing is done.  There are three
   possible types of external facing connections associated with an



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   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-nni: The site represents an NNI where two
      administrative domains belonging to the same or different
      providers inter-connect with each other.

   o  site-vpn-flavor-e2e: The site represents end to end mult-segment
      connection.

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.

                                                         +--------+
      +------------------+             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.



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   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.  NNI: site-vpn-flavor-nni

   A Network-to-Network Interface (NNI) 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 NNI,
   as specific default device configuration parameters may be applied in
   the case of NNIs (e.g., ACLs, routing policies).

            SP A                                             SP B
       -------------------                         -------------------
      /                   \                       /                   \
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 + (MAC-VRF1)-(VPN1)-(MAC-VRF1)+                 |
     |                 + ASBR +               + ASBR +                 |
     |                 + (MAC-VRF2)-(VPN2)-(MAC-VRF2)+                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 + (MAC-VRF1)-(VPN1)-(MAC-VRF1)+                 |
     |                 + ASBR +               + ASBR +                 |
     |                 + (MAC-VRF2)-(VPN2)-(MAC-VRF2)+                 |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
      \                   /                       \                   /
       -------------------                         -------------------

   The figure above describes an option A NNI 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-nni will be used
   to inform SP B that this is an NNI and not a regular customer site.






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5.5.1.4.  E2E: site-vpn-flavor-e2e

   A end to end multi-segment VPN connection to be constructed out of
   several connectivity segments may be modeled.  It is helpful for the
   SP to indicate the requested VPN connection is not a regular site but
   rather is an end to end VPN connectivity, as specific default device
   configuration parameters may be applied in case of site-vpn-flavor-
   e2e (e.g., QoS configuration).  In order to establish connection
   between Site 1 in SP A and Site 2 in SP B spanning across multi-
   domains, SP A may request the creation of end to end connectivity to
   SP B.  The site-vpn-flavor-e2e will be used to inform that this is an
   end to end connectivity setup 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.

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.

















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      <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>
             <filters>
               <filter>
                 <lan-tag>LAN1</lan-tag>
               </filter>
             </filters>
             <vpn>
              <vpn-id>VPN2</vpn-id>
              <site-role>hub-role</site-role>
             </vpn>
            </entries>
            <entries>
             <id>ENTRY2</id>
             <filters>
               <filter>
                 <lan-tag>LAN2</lan-tag>
               </filter>
             </filters>
              <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).





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

   The management system MUST honor all customer constraints, or if a
   constraint is too strict and cannot be fulfilled, the management
   system MUST NOT provision the site and MUST provide information to
   the user about which constraints that could not be fulfilled.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 such as site location (see Section 5.6.2) and access type
   are just hints (see Section 5.6.3) 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 to a particular already-
   configured location.  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



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   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
   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



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   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.

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.







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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.

   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.




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   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.

   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 MAC-VRF
   on the target PE and an RD for this MAC-VRF.This RD MUST be unique
   across all MAC-VRFs on the target PE.

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

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

   The management system MAY apply a per-VPN or per-MAC-VRF allocation
   policy for the RD, depending on the SP's policy.  In a per-VPN
   allocation policy, all MAC-VRFs (dispatched on multiple PEs) within a
   VPN will share the same RD value.  In a per-MAC-VRF model, all MAC-
   VRF should always have a unique RD value.  Some other allocation



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   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 5.2.3.1 could be reused in this
   scenario.

   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)




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   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.

   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 ingress bandwidth
   and egress bandwidth.  Ingress/egress direction is using customer
   site as reference: Ingress direction bandwidth means download
   bandwidth for the site, and egresss 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 ingress and egress bandwidth will allow service
   provider to know if a customer allows for asymmetric bandwidth access




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   like ADSL.  It can also be used to set different rate limit in a
   different way for upload and download on symmetric bandwidth access.

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

   o  bw-per-access Bandwidth is per connection or site network access,
      providing rate enforcement for all service frames at the interface
      that are associated with a particular 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-svc bandwidth is per site, providing rate enforcement for
      all service frames that are associated with a particular vpn
      service.

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

   The svc-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. service frames are metered against
   the bandwidth profile based on the cos- identifier.

   The svc-bandwidth must be associated specific "site-network-access-
   id" parameter if the 'type' is set as 'bw-per-access'.  Multiple
   bandwidth per-cos-id can be associated with the same Site Network
   access.

   The svc-bandwidth must include specific "vpn-id" parameter if the
   'type' is set as 'bw-per-svc'.  Multiple bandwidth per-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.







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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.

   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.  In such a case, an association between the
   site abstraction and the MAC addresses used by this site must be done
   dynamically.  How this association is done is out of scope for this
   document.  The association of a site to an L2VPN is done through the
   "vpn-attachment" container.  Therefore the user can also employ
   "target-sites" leaf-list and "vpn-attachment" to identify the
   destination of a flow targeted to specific vpn service.  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.  The current model
   defines some applications, but new application identities may be
   added through augmentation.  The exact meaning of each application
   identity is up to the SP, so it will be necessary for the SP to
   advise the customer on the usage of application matching.

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  direction: Used to specify the direction which qos profile is
      applied to.  Our proposed model supports "Site-to-WAN" direction,
      "WAN-to-Site"direction and "both" direction.  By default, "both"
      direction is used.  In case of "both" direction, the provider
      should ensure scheduling according to the requested policy in both



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      traffic directions (SP to customer and customer to SP).  As an
      example, a device-scheduling policy may be implemented on both the
      PE side and the CE side of the WAN link.  In case of "WAN-to-Site"
      direction, the provider should ensure scheduling from the SP
      network to the customer site.  As an example, a device- scheduling
      policy may be implemented only on the PE side of the WAN link
      towards the customer.

   o  policing: The optional "policing" indicates whether policing
      setting is one rates two colors or two rates, three colors.

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

   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.  The available bandwidth should not fall below
      Committed Information Rate(CIR) defined under svc-input-bandwidth
      or svc-output-bandwidth.  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-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.




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   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.  Broadcast Multicast Unknow Unicast Support

   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-
   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:




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   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.  MAC Loop Protection

   MAC address flapping between different physical ports typically
   indicates a bridge loop condition in the customer 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.

   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.

5.13.  MAC Address Limit

   The optional "mac-address-limit" container contains the customer MAC
   address limit and information to describe the action when the limit
   is exceeded and the aging time for a MAC address.

   When multiple services are provided on the same network element, the
   MAC address table (and the Routing Information Base space for MAC-



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   routes in the case of EVPN) is a shared common resource.  Service
   providers may impose a maximum number of MAC addresses learned from
   the customer for a single service instance by using 'mac-limit'leaf,
   and may use 'action' leaft to 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.

5.14.  Enhanced VPN Features

5.14.1.  Carriers' Carriers

   In the case of CsC [RFC6624], a customer may want to build an MPLS
   service using an L2VPN to carry its traffic.

              LAN customer1
                  |
                  |
                 CE1
                  |
                  | -------------
               (vrf_cust1)
                CE1_ISP1
                  |                 ISP1 POP
                  | MPLS link
                  | -------------
                  |
               (vrf ISP1)
                 PE1

                (...)               Provider backbone

                 PE2
                (vrf ISP1)
                  |
                  | ------------
                  |
                  | MPLS link
                  |                 ISP1 POP
                 CE2_ISP1
                 (vrf_cust1)
                  | ------------
                  |
                 CE2
                  |
               LAN customer1



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   In the figure above, ISP1 resells an L2VPN service but has no core
   network infrastructure between its POPs.  ISP1 uses an L2VPN as the
   core network infrastructure (belonging to another provider) between
   its POPs.

   In order to support CsC, the VPN service must indicate MPLS support
   by setting the "carrierscarrier" leaf to true in the vpn-service
   list.  The link between CE1_ISP1/PE1 and CE2_ISP1/PE2 must also run
   an MPLS signalling protocol.  This configuration is done at the site
   level.

   In the proposed model, LDP or BGP can be used as the MPLS signalling
   protocol.  In the case of LDP, an IGP routing protocol MUST also be
   activated.  In the case of BGP signalling, BGP MUST also be
   configured as the routing protocol.

   If CsC is enabled, the requested "svc-mtu" leaf will refer to the
   MPLS MTU and not to the link MTU.

5.15.  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.

5.16.  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 (MAC-VRF) 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.

5.16.1.  Defining an NNI with the Option A Flavor

              AS A                                          AS B
       -------------------                         -------------------
      /                   \                       /                   \
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +(MAC-VRF1)-(VPN1)--(MAC-VRF1) +                |
     |                 + ASBR +               + ASBR +                 |
     |                 + (MAC-VRF2)-(VPN2)--(MAC-VRF2)+                |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
     |                     |                     |                     |
     |                 ++++++++ Inter-AS link ++++++++                 |
     |                 +      +_______________+      +                 |
     |                 +(MAC-VRF1)--(VPN1)--(MAC-VRF1)+                |
     |                 + ASBR +               + ASBR +                 |
     |                 +(MAC-VRF2)--(VPN2)--(MAC-VRF2)+                |
     |                 +      +_______________+      +                 |
     |                 ++++++++               ++++++++                 |
     |                     |                     |                     |
     |                     |                     |                     |
      \                   /                       \                   /
       -------------------                         -------------------

   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
   |       |--------(MAC-VRF1)-(VPN1)-(MAC-VRF1)+             |
   |       |       + 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:






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      <site>
          <site-id>CSP_A_attachment</site-id>
            <location>
              <city>NY</city>
              <country-code>US</country-code>
           </location>
          <site-vpn-flavor>site-vpn-flavor-nni</site-vpn-flavor>
            <site-network-accesses>
              <site-network-access>
               <site-network-access-id>CSP_A_VN1</site-network-access-id>
                       <connection>
                       <encapsulation-type>vlan</encapsulation-type>
                       <eth-inf-type>tagged<eth-inf-type>
                        <tagged-interface>
                         <tagged-inf-type>dot1q-vlan</tagged-inf-type>
                         <dot1q-vlan-tagged>
                          <vlan-id>17</vlan-id>
                        </dot1q-vlan-tagged>
                        </tagged-interface>
                       </connection>
                         <service>
                           <svc-bandwidth>
                             <bandwidth>
                             <direction>input-bw</direction>
                             <type>opaque</type>
                             <cir>450000000</cir>
                             <cbs>20000000</cbs>
                             <eir>1000000000</eir>
                             <ebs>200000000</ebs>
                           </svc-bandwidth>
                           <carrierscarrier>
                             <signaling-type>bgp</signaling-type>
                          </carrierscarrier>
                         </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>
          </management>
      </site>

   The case described above is different from a scenario using the
   cloud-accesses container, as the cloud-access provides a public cloud




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   access while this example enables access to private resources located
   in a CSP network.

5.16.2.  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
       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.



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   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.

           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



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   A to the customer L2VPN (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.

5.16.3.  Defining an NNI with the Option C Flavor

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




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   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.

5.17.  Applicability of L2SM model in Inter-Provider and Inter-Domain
       Orchestration

   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
   approaches 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 may be realized
   using stitching of Per Site connectivity and service segment at
   different domains, e.g., end to end connectivity between site_1 and
   Site 3 spans across multiple domains(i.e., Metro networks described
   in section 5.2.5.) and can be constructed by stitching network access
   connectivity within site_1 with SEG1, SEG3, SEG4 and network access
   connectivity within site3 (See the following figure).  The assumption
   is service orchestration layer in figure 5 should have visibility of
   the complete abstract topology and resource availability.  This may
   rely on network planning to achieve that.

   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.











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              ----------   ----------   ----------
             |          | |          | |          |
           +--+        +---+        +---+        +--+
     Site_1|PE|==SEG1==|   |==SEG3==|   |==SEG4==|PE|Site_3
           +--+        +---+        |   |        +--+
             |          | |         |   |         |  ----------
             |          | |         |   |         | |          |
           +--+        +---+        |   |        +---+        +--+
     Site_2|PE|==SEG2==|   |==SEG5==|   |==SEG6==|   |==SEG7==|PE|Site_4
           +--+        +---+        +---+        +---+        +--+
             |          | |          | |          | |          |
              ----------   ----------   ----------   ----------

   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




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   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)

   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.



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   o  Physical interface.

   o  Ethernet layer (VLAN ID).

   o  QoS: classification, profiles, etc.

   o  Ethernet Service OAM Support.

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 to provide a VPN service for 3 sites using point-to-
   point VPWS and a Hub and Spoke VPN service topology as shown in
   Figure Figure 5.  Loadbalancing is not considered in this case.

      Site1
      ............
      :          :             P2P VPWS
      :Spoke Site:-----PE1--------------------------+
      :          :                                  |        Site3
      :..........:                                  |      ............
                                                    |      :          :
                                                   PE3-----: Hub Site :
      Site2                                         |      :          :
      ............                                  |      :..........:
      :          :             P2P VPWS             |
      :Spoke Site:-----PE2--------------------------+
      :          :
      :..........:

              Figure 5: 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-type>vpws</svc -type>
                     <svc-topo>hub-spoke</svc-topo>
                </vpn-service>

                <vpn-service>
                     <vpn-id>12456488</vpn-id>
                     <svc-type>vpws</svc -type >
                     <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 Site1.

              <site>
                <site-id>Spoke_Site1</site-id>
                <location>
                   <city>NY</city>
                   <country-code>US</country-code>
                </location>
                <site-network-accesses>
                  <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>
                     <encapsulation-type>dot1q</encapsulation-type>
                      <tagged-interface>
                      <dot1q-vlan-tagged>
                        <cvlan-id>17</cvlan-id>
                      </dot1q-vlan-tagged>
                      </untagged-interface>
                      <l2cp-control>
                        <stp-rstp-mstp>TUNNEL</stp-rstp-mstp>
                        <lldp>TRUE</lldp>
                      </l2cp-control>
                    </connection>
                    <service>



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                      <svc-bandwidth>
                        <bandwidth>
                        <direction>input-bw</direction>
                        <type>opaque</type>
                        <cir>450000000</cir>
                        <cbs>20000000</cbs>
                        <eir>1000000000</eir>
                        <ebs>200000000</ebs>
                        </bandwidth>
                      </svc-bandwidth>
                      <carrierscarrier>
                       <signaling-type>bgp</signaling-type>
                      </carrierscarrier>
                   </service>
                    <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>

   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 MUST 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 VSI is already present that fits the needs.  If not,
   it will provision the VSI: 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



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   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 vsi 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 VSI 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.

   Example of generated PE configuration:
























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   !
   bridge-domain 1
    member Ethernet0/0 service-instance 100
    member vsi 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 MAC-VRF at the PE
     xconnect vsi 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
   within subnet.  This will allow to produce a plug'n'play
   configuration for the CE.



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   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@2018-01-08.yang"
module ietf-l2vpn-svc {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-l2vpn-svc";
prefix l2vpn-svc;
import ietf-inet-types {
 prefix inet;
}
import ietf-yang-types {
 prefix yang;
}
import ietf-netconf-acm {
 prefix nacm;
}
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 2018-01-08{
description
 "Initial revision -04 version";
reference
 "draft-ietf-l2sm-l2vpn-service-model-05.txt
 A YANG Data Model for L2VPN Service Delivery.";
}
/* Features */
feature carrierscarrier {
 description
  "Enables support of CsC.";



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}

feature frame-delivery{
 description
  "Enables frame-delivery capabilities support in a L2VPN.";
}

feature extranet-vpn{
 description
  "Enable the Support of Extranet VPN.";
}
feature L2CP-control {
 description
  "Enable the Support of L2CP control.";
}
feature input-bw {
 description
  "Enable the suppport of Input Bandwidth in a VPN.";
}
feature output-bw {
 description
  "Enable the support of Output Bandwidth in a VPN";
}
feature uni-list {
 description
  "Enable the support of UNI list in a VPN.";
}
feature cloud-access {
 description
  "Allow VPN to connect to a Cloud Service
provider.";
}
feature oam-3ah {
 description
  "Enables the support of OAM 802.3ah.";
}
feature micro-bfd {
 description
  "Enables the support of Micro-BFD.";
}
feature bfd {
 description
  "Enables the support of BFD.";

}
feature signaling-options {
 description
  "Enable the support of signalling option.";



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}
feature site-diversity {
 description
  "Enables the support of site diversity constraints in a VPN.";
}
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 the support of VLAN.";
}
feature dot1q{
 description
  "Enable the support of Dot1Q.";
}
feature sub-inf{
 description
  "Enable the support of Sub Interface.";
}



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feature qinq {
 description
  "Enable the support of QinQ.";
}
feature qinany{
 description
  "Enable the support of QinAny.";

}
feature vxlan {
 description
  "Enable the support of VxLAN.";
}
feature lan-tag {
 description
  "Enables LAN Tag support in a VPN.";
}
feature target-sites {
 description
  "Enables support of the 'target-sites' match flow parameter.";
}
/* Typedefs */
typedef svc-id {
 type string;
 description
  "Defines a type of service component identifier.";
}
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,i.e.,participate in the protocol towards the CE.
    Peering is common for LACP  and E-LMI and occasionally
    for LLDP. For virtual private services the Subscriber
    can also request that the Service Provider peer
    spanning tree.";
}
 enum tunnel {
  description
   "Tunnel mode,i.e.,pass to the egress or destination site.



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    For EPL, the expectation is that L2CP frames are tunneled.";
}
 enum discard {
  description
  "Discard mode,i.e.,discard the frame.";
}
}
description
"Defining a type of the control mode on L2CP protocols.";
}
typedef neg-mode {
 type enumeration {
 enum full-duplex {
  description
   "Defining Full duplex mode";
 }
 enum auto-neg {
  description
   "Defining Auto negotiation mode";
 }
}
description
 "Defining a type of the negotiation mode";
}

/* Identities */
identity site-network-access-type {
 description
  "Base identity for site-network-access type.";
}
identity point-to-point {
 base site-network-access-type;
  description
   "Identity for point-to-point connection.";
}
identity multipoint {
 base site-network-access-type;
  description
   "Identity for multipoint connection.
    Example: Ethernet broadcast segment.";
}
identity tag-type {
 description
  "Base identity from which all tag types
   are derived from";
}
identity c-vlan {
 base tag-type;



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 description
  "A Customer-VLAN tag, normally using the 0x8100
   Ethertype";
}
identity s-vlan {
 base tag-type;
 description
  "A Service-VLAN tag.";
}
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{
 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";
}



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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 encapsulation-type {
 description
  "Identity for encapsulation type";
}
identity ethernet {
 base encapsulation-type;
 description
  "Identity for ethernet type";
}
identity vlan {
 base encapsulation-type;
 description
  "Identity for VLAN  type";
}
identity carrierscarrier-type{
 description
  "Identity of carrierscarrier";
}
identity ldp {
 base carrierscarrier-type;
 description
  "Use LDP as the signalling protocol
   between the PE and the CE.";
}
identity bgp {
 base carrierscarrier-type;
 description
  "Use BGP (as per RFC 3107) as the signalling protocol
   between the PE and the CE.
   In this case, BGP must also be configured as
   the routing protocol.";
}
identity eth-inf-type {



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 description
  "Identity of Ethernet Interface Type.";
}
identity tagged {
 base eth-inf-type;
 description
  "Identity of tagged Interface type.";
}
identity untagged {
 base eth-inf-type;
 description
  "Identity of untagged Interface type.";
}
identity lag {
 base eth-inf-type;
 description
  "Identity of LAG Interface type";
}
identity bw-type {
 description
  "Identity of bandwidth";
}
identity bw-per-cos {
 base bw-type;
 description
  "Bandwidth is per cos";
}
identity bw-per-port {
 base bw-type;
 description
  "Bandwidth is per site network access";
}

identity opaque {
 base bw-type;
 description
  "Opaque";
}
identity site-vpn-flavor {
 description
  "Base identity for the site VPN service flavor.";
}
identity site-vpn-flavor-single {
 base site-vpn-flavor;
 description
  "Base identity for the site VPN service flavor.
   Used when the site belongs to only one VPN.";
}



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identity site-vpn-flavor-multi {
 base site-vpn-flavor;
 description
  "Base identity for the site VPN service flavor.
   Used when a logical connection of a site
   belongs to multiple VPNs.";
}
identity site-vpn-flavor-nni {
 base site-vpn-flavor;
 description
  "Base identity for the site VPN service flavor.
   Used to describe an NNI option A connection.";
}
identity service-type {
 description
  "Base Identity of service type.";
}
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 ldp-l2tp-vpls {
 base service-type;
 description
  "LDP based or L2TP based multipoint Virtual Private LAN
   services (VPLS) Service Type.This VPLS uses LDP-signaled
   Pseudowires or L2TP signaled Pseudowires.";
}
identity bgp-vpls {
 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 vpws-evpn {
 base service-type;
 description
  "VPWS Service Type using Ethernet VPN(EVPN) specified in RFC 7432.";
}
identity pbb-evpn {



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 base service-type;
 description
  "PBB Service Type using Ethernet VPN(EVPN) specified in RFC 7432.";
}
identity bundling-type {
 description
  "This is base identity for Bundling type. It supports
   multiple CE-VLAN associated with L2VPN service or
   all CE-VLANs associated with L2VPN service.";
}
identity multi-svc-bundling {
 base bundling-type;
 description
  "Identity for multiple service bundling,i.e.,
   multiple CE-VLAN IDs can be associated with an
   L2VPN Service at site.";
}
identity one2one-bundling {
 base bundling-type;
 description
  "Identity for one to one service bundling,i.e.,
   Each L2VPN can be associated with only one CE-VLAN IDs
   at site.";
}
identity all2one-Bundling {
 base bundling-type;
 description
  "Identity for all to one bundling,i.e.,all CE-VLAN IDs
   are mapped to one L2VPN Service";
}
identity color-id {
 description
  "base identity of color id";
}

identity color-id--cvlan {
 base color-id;
 description
  "Identity of color id base on  CVLAN ";
}
identity cos-id {
 description
  "Identity of class of service id";
}
identity cos-id-pcp {
 base cos-id;
 description
  "Identity of cos id based on  PCP";



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

}
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 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



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  "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;
 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";



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}
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
  "Identity of LACP slow";
}
identity bw-direction{
 description
  "Identity for bandwidth direction";
}
identity input-bw{
 base bw-direction;
 description
  "Identity for input bandwidth";
}
identity output-bw{
 base bw-direction;
 description
  "Identity for output bandwidth";
}
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 frame-delivery-mode {
 description
  "Delivery types";
}
identity discard {
 base frame-delivery-mode;
 description
  "Service Frames are discarded.";
}
identity unconditional {
 base frame-delivery-mode;
 description
  "Service Frames are unconditionally
   delivered to the destination site.";
}
identity unknown-discard {
 base frame-delivery-mode;
 description
  "Service Frame are conditionally
   delivered to the destination site and
   the packet with unknown destination address
   will be discarded.";
}
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.";
}



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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 tagged-inf-type {
 description
  "Identity for the tagged
   interface type.";
}
identity priority-tagged {
 base tagged-inf-type;
 description
  "This identity the priority-tagged interface.";
}
identity qinq{
 base tagged-inf-type;
 description
  "Identity for the qinq tagged interface.";
}
identity dot1q{
 base tagged-inf-type;
 description
  "Identity for dot1q vlan tagged interface.";
}



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identity qinany{
 base tagged-inf-type;
 description
  "Identity for qinany tagged inteface.";
}
identity vxlan{
 base tagged-inf-type;
 description
  "Identity for vxlan tagged inteface.";
}
identity provision-model {
 description
  "base identity for provision model.";
}
identity single-side-provision {
 description
  "Identity for single side provisioning with discovery.";
}
identity doubled-side-provision {
 description
  "Identity for double side provisioning.";
}
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";
}
identity vpn-policy-filter-type {
  description
   "Base identity for filter type.";
}
identity lan {
  base vpn-policy-filter-type;
  description
   "Identity for lan tag filter type.";
}
identity mac-action {
 description
  "Base identity for MAC action.";



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 }
identity drop {
 base mac-action;
 description
  "Identity for packet drop.";
}

identity flood {
 base mac-action;
 description
  "Identity for packet flooding.";
}
identity warning {
 base mac-action;
 description
  "Identity for sending a warning log message.";
}
identity load-balance-method {
 description
  "Base identity for load balance method.";
}
identity fat-pw {
 base load-balance-method;
 description
  "Identity for Fat PW. Fat label is
   applied to Pseudowires across MPLS
   network.";
}
identity entropy-label {
 base load-balance-method;
 description
  "Identity for entropy label.Entropy label
   is applied to IP forwarding,
   L2VPN or L3VPN across MPLS network";
}
identity vxlan-source-port {
 base load-balance-method;
 description
  "Identity for vxlan source port.VxLAN
   Source Port is one load balancing method.";
}
identity qos-profile-direction {
 description
  "Base identity for qos profile direction.";
 }
identity site-to-wan {
 base qos-profile-direction;
 description



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  "Identity for Site to WAN direction.";
 }
identity wan-to-site {
 base qos-profile-direction;
 description
  "Identity for WAN to Site direction.";
}
identity bidirection {
 base qos-profile-direction;
 description
  "Identity for both WAN to Site direction
   and Site to WAN direction.";
}
identity vxlan-peer-mode {
 description
  "Base identity for vxlan peer mode.";
}
identity static-mode {
 base vxlan-peer-mode;
 description
  "Identity for the vxlan access in static mode.";
}
identity bgp-mode {
 base vxlan-peer-mode;
 description
  "Identity for the vxlan access by bgp evpn learning.";
}
identity customer-application {
 description
  "Base identity for customer application.";
 }
identity web {
 base customer-application;
 description
  "Identity for Web application (e.g., HTTP, HTTPS).";
}
identity mail {
 base customer-application;
 description
  "Identity for mail application.";
}
identity file-transfer {
 base customer-application;
 description
  "Identity for file transfer application (e.g., FTP, SFTP).";
}
identity database {
 base customer-application;



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 description
  "Identity for database application.";
}
identity social {
 base customer-application;
 description
  "Identity for social-network application.";
}
identity games {
 base customer-application;
 description
  "Identity for gaming application.";
}
identity p2p {
 base customer-application;
 description
  "Identity for peer-to-peer application.";
}
identity network-management {
 base customer-application;
 description
  "Identity for management application
   (e.g., Telnet, syslog, SNMP).";
 }
identity voice {
 base customer-application;
 description
  "Identity for voice application.";
}
identity video {
 base customer-application;
 description
  "Identity for video conference application.";
}
identity embb {
 base customer-application;
 description
  "Identity for enhanced Mobile Broadband(eMBB)
   application. Note that eMBB application demands
   the network performance with wide variety of
   characteristics such as data rate, latency,
   loss rate, reliability and many other parameters.";
}
identity urllc {
 base customer-application;
 description
  "Identity for Ultra-Reliable and Low Latency
   Communications (URLLC) application. Note that



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   URLLC application demands the network performance
   with wide variety of characteristics such as latency,
   reliability and many other parameters.";
 }
identity mmtc {
  base customer-application;
  description
   "Identity for massive Machine Type
    Communications (mMTC) application. Note that
    mMTC application demands the network performance
    with wide variety of characteristics such as data
    rate, latency, loss rate, reliability and many
    other parameters.";
 }
/* Groupings */
grouping vpn-service-cloud-access {
 container cloud-accesses {
  if-feature cloud-access;
  list cloud-access {
   key cloud-identifier;
   leaf cloud-identifier {
   type leafref {
    path "/l2vpn-svc/vpn-profiles/"+
    "valid-provider-identifiers/cloud-identifier/id";
    }
   description
    "Identification of cloud service.
    Local administration 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 {



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    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";
}

grouping site-vpn-flavor {
 leaf site-vpn-flavor {
  type identityref {
   base site-vpn-flavor;
  }
  default site-vpn-flavor-single;
  description
   "Defines the way the VPN multiplexing is done ,e.g.,whether
   the site belongs to a single VPN site or a multiVPN;";
 }
 description
  "Grouping for site VPN flavor.";
}

grouping site-device {
 container devices {
  when "derived-from-or-self(../management/type, 'l2vpn-svc:provider-managed') or "+
   "derived-from-or-self(../management/type, 'l2vpn-svc:co-managed')" {
  description
   "Applicable only for provider-managed or
    co-managed device.";
  }
 list device {
  key "device-id";
  leaf device-id {
  type string;
  description
   "Identifier for the device.";



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  }
  leaf location {
   type leafref {
    path "../../../locations/"+
    "location/location-id";
   }
   mandatory true;
   description
    "Location of the device.";
  }
  container management {
   when "derived-from-or-self(../../../management/type,"+
     "'l2vpn-svc:co-managed')" {
     description
      "Applicable only for co-managed device.";
    }
  leaf management-transport {
   type identityref {
   base address-family;
   }
   description
    "Transport protocol or Address family used for management.";
  }
   leaf address {
    when "(../management-transport)" {
    description
      "If address-family is specified, then address should
       also be specified.If management transport is not specified,
       then address should also not be specified.";
     }
   type inet:ip-address;
   description
    "Management address.";
   }
 description
  "Management configuration. Applicable only for
    co-managed device.";
}
 description
  "List of devices requested by customer.";
}
description
 "Devices configuration";
}
description
"Device parameters for the site.";
}
grouping site-management {



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 container management {
  leaf type {
  type identityref {
   base management;
  }
  mandatory true;
  description
   "Management type of the connection.";
 }
 description
  "Management configuration.";
 }
 description
  "Management parameter for the site.";
}
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 filters {
    list filter {
     key type;
     ordered-by user;
     leaf type {
      type identityref {
       base vpn-policy-filter-type;
      }
     description
      "Type of VPN Policy filter.";
     }
     leaf-list lan-tag {
      when "derived-from-or-self(../type, 'l2vpn-svc:lan')" {
       description
        "Only applies when VPN Policy filter is LAN Tag filter.";
      }
      if-feature lan-tag;



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      type uint32;
      description
       "List of Ethernet LAN Tag to be matched. Ethernet LAN Tag
        identifies a particular broadcast domain in a VPN. ";
     }
    description
      "List of filters used on the site. This list can
       be augmented.";
    }
    description
     "If a more-granular VPN attachment is necessary, filtering can
      be used. If used, it permits the splitting of site LANs among
      multiple VPNs.The Site LAN can be split based on either LAN-tag
      or LAN prefix. If no filter is used, all the LANs will be
      part of the same VPNs with the same role.";
     }

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



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description
 "VPN policy parameters for the site.";
}

grouping bum-frame-delivery {
 container bum-frame-delivery {
  list bum-frame-delivery {
   key frame-type;
   leaf frame-type {
    type identityref {
     base tf-type;
    }
    description
     "Type of frame delivery. It support unicast
      frame delivery, multicast frame delivery
       and broadcast frame delivery.";
    }
   leaf delivery-mode {
    type identityref {
     base frame-delivery-mode;
    }
   description
    "Define Frame Delivery Mode
    (unconditional[default], conditional, or discard).";
    }
  description
   "List of frame delivery type and mode.";
 }
 description
  "Define frame delivery type and mode.";
}
description
 "Grouping for unicast, mulitcast, broadcast frame delivery";
}

grouping cvlan-svc-map-grouping {
 list cvlan-id-to-svc-map {
  key "svc-id";
  leaf svc-id {
   type leafref {
    path "/l2vpn-svc/vpn-services/vpn-service/vpn-id";
   }
   description
    "VPN Service identifier";
  }
  list cvlan-id {
   key vid;
   leaf vid {



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    type uint16;
    description
     "CVLAN ID";
    }
   description
    "List of CVLAN-ID to SVC Map configurations";
  }
  description
   "List for cvlan-id to L2VPn Service map configurations";
 }
 description
  "Grouping for cvlan to L2VPN service mapping";
}

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;
    description



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     "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 vpn-service-multicast {
 container frame-delivery {
  if-feature frame-delivery;
  container customer-tree-flavors {
   leaf-list tree-flavor {
    type identityref {
     base multicast-tree-type;
    }
    description
     "Type of tree to be used.";



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   }
   description
    "Type of trees used by customer.";
   }
  uses bum-frame-delivery;
  leaf multicast-gp-port-mapping {
   type identityref {
    base mapping-type;
   }
   mandatory true;
   description
    "Describe the way in which each interface is
     associated with the Multicast group";
  }
  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
     "Identifies the target VPN the local VPN want to access.";
    }
   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. In the any-to-any VPN service topology,
    the local 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,
    the local sites must have a Hub role or a Spoke role";
  }
  description
   "List of extranet VPNs the local VPN is attached to.";
 }
 description



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  "Container for extranet VPN configuration.";
 }
 description
  "Grouping for extranet VPN configuration.
   This provides an easy way to interconnect
   all sites from two VPNs.";
}

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
    site actually stopped";
    }
 leaf bundling-type {
  type identityref {
   base bundling-type;
   }
  description
   "Bundling type";
  }
 leaf default-ce-vlan-id {
  type uint32;
  description
   "Default CE VLAN ID set at site level.";
  }
 description
  "This grouping defines some operational parameters
   parameters";
}

grouping cfm-802-grouping {
 leaf maid {
  type string;
  description
   "Identify an Maintenance Association (MA).";
  }



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 leaf mep-id {
  type uint32;
  description
  "Local Maintenance End Point (MEP) ID";
  }
 leaf mep-level {
  type uint32;
  description
  "Define Maintenance End Point (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";
  }
 leaf cos-for-cfm-pdus {
  type uint32;
  description
   "COS for CFM PDUs";
 }
 leaf ccm-interval {
  type uint32;
  description
   " Continuity Check Message(CCM) interval.";
 }
 leaf ccm-holdtime {
  type uint32;
  description
   "CCM hold time";
 }
 leaf alarm-priority-defect {
  type identityref {
   base fault-alarm-defect-type;
  }



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 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 attributes.";
}

grouping y-1731 {
 list y-1731 {
  key maid;
  leaf maid {
   type string;
   description
    "Identify an Maintenance Association (MA). ";
  }
  leaf mep-id {
   type uint32;
   description
    "Local Maintenance End Point(MEP) ID.";
  }
 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;



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  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
    "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.";



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    }
  }
  description
   "Session type.";
  }
  description
   "List for y-1731.";
 }
 description
  "Grouping for y.1731.";
}

grouping site-acl {
 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 List.";
 }
 description
  "This grouping defines Access Control List.";
}

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 uint32;
   description
    "LACP speed.";
  }



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  leaf mini-link {
   type uint32;
   description
    "The minimum aggregate bandwidth for a LAG.";
  }
  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
     "BFD activation";
   }



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  choice holdtime {
   default fixed;
   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 link-mtu {
     type uint32;
     description
      "Link MTU size.";
    }



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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 lldp {
   type boolean;
   description
    "LLDP.";
  }
  description
   "LACP.";
 }
 description
  "Grouping for lacp.";
}

grouping untagged-interface-grouping {
 container untagged-interface {
  leaf ifindex {
   type uint32;
   description
    "Index for the physical interface.";
  }
  leaf port-speed {
   type uint32;
   description
    "Port speed.";
  }
  leaf mode {
   type neg-mode;
   description



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    "Negotiation mode.";
  }
  leaf phy-mtu {
   type uint32;
   description
    "PHY MTU.";
  }
  leaf flow-control {
   type string;
   description
    "Flow control.";
  }
  leaf lldp {
   type boolean;
   description
    "LLDP.";
  }
 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.";
 }
 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 Untagged Interface Attributes
   configurations.";
 }
 description
  "Grouping for Untagged interface.";
}

grouping lag-interface-grouping {
 container lag-interface {
  if-feature lag-interface;
  list lag-interface {
   key "lag-ifindex";
   leaf lag-ifindex {
    type uint32;



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    description
     "LAG interface index.";
     }
   uses lacp-grouping;
   description
    "List of LAG interfaces.";
   }
  description
   "Container of LAG interface attributes configuration";
  }
 description
  "Grouping for LAG interface";
}

grouping tagged-interface-grouping {
 container tagged-interface {
  leaf tagged-inf-type {
  type identityref {
   base tagged-inf-type;
  }
  description
   "Tagged interface type.";
  }
 container dot1q-vlan-tagged {
   when "derived-from-or-self(../tagged-inf-type, 'l2vpn-svc:dot1q')" {
   description
    "Only applies when Tagged interface type is dot1q.";
   }
 if-feature dot1q;
 leaf tag-type {
  type identityref{
  base tag-type;
  }
  description
   "TAG type.";
 }
 leaf cvlan-id {
  type uint16;
  description
   "VLAN identifier.";
 }
 description
  "Tagged interface.";
}
 container priority-tagged {
  when "derived-from-or-self(../tagged-inf-type, 'l2vpn-svc:priority-tagged')" {
   description
    "Only applies when Tagged interface type



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    is priority tagged interface.";
  }
  leaf tag-type {
   type identityref{
   base tag-type;
   }
  description
   "TAG type.";
  }
  description
   "Priority tagged.";
 }
 container qinq {
  when "derived-from-or-self(../tagged-inf-type, 'l2vpn-svc:qinq')" {
  description
   "Only applies when Tagged interface type is qinq.";
   }
  if-feature qinq;
  leaf tag-type {
   type identityref{
   base tag-type;
   }
   description
    "Tag type.";
   }
  leaf svlan-id {
   type uint16;
   description
    "S-VLAN Identifier.";
  }
  leaf cvlan-id {
   type uint16;
   description
   "C-VLAN Identifier";
  }
 description
  "QinQ.";
 }
 container qinany {
  when "derived-from-or-self(../tagged-inf-type, 'l2vpn-svc:qinany')" {
  description
   "Only applies when Tagged interface type is qinany.";
  }
  if-feature qinany;
  leaf tag-type {
   type identityref{
   base tag-type;
  }



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  description
   "Tag type.";
  }
  leaf svlan-id {
   type uint16;
   description
    "S-Vlan ID.";
  }
  description
   "Container for Q in Any.";
 }
 container vxlan {
  when "derived-from-or-self(../tagged-inf-type, 'l2vpn-svc:vxlan')" {
  description
   "Only applies when Tagged interface type is vxlan.";
  }
  if-feature vxlan;
  leaf vni-id {
   type uint32;
   description
    "VNI Identifier.";
  }
  leaf peer-mode {
   type identityref {
    base vxlan-peer-mode;
   }
   description
    "specify the vxlan access mode";
  }
  list peer-list {
   key peer-ip;
   leaf peer-ip {
    type inet:ip-address;
    description
     "Peer IP.";
   }
   description
    "List for peer IP.";
  }
  description
   "QinQ.";
  }
  description
   "Container for tagged Interface.";
 }
 description
  "Grouping for tagged interface.";
}



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grouping site-attachment-ethernet-connection {
 container connection {
  leaf encapsulation-type {
  type identityref {
   base encapsulation-type;
  }
  description
   "Encapsulation Type";
  }
  leaf eth-inf-type {
   type identityref {
    base eth-inf-type;
   }
   description
    "Ethernet Interface Type";
  }
 uses tagged-interface-grouping;
 uses untagged-interface-grouping;
 uses lag-interface-grouping;
 uses cvlan-svc-map-grouping;
 uses l2cp-grouping;
 uses ethernet-svc-oam-grouping;
 description
  "Container for bearer";
 }
 description
  "Grouping for bearer.";
}

grouping svc-mtu {
 leaf svc-mtu {
  type uint16;
  units bytes;
  mandatory true;
  description
   "SVC MTU, it is also known as the maximum transmission unit or
    maximum frame size,When a frame is larger than the MTU, it is
    broken down, or fragmented, into smaller pieces by the network
    protocol to accommodate the MTU of the network. If CsC is
    enabled,the requested svc-mtu leaf will refer to the
    MPLS MTU and not to the link MTU. ";
  }
 description
  "Grouping for service mtu.";
}

grouping svc-preservation-grouping {
 leaf ce-vlan-preservation {



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  type boolean;
  description
   "Preserve the CE-VLAN ID from ingress to egress,i.e.,
    CE-VLAN tag of the egress frame are identical to
    those of the ingress frame that yielded this
    egress service frame. If All-to-One bundling within a site
    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 1
    through 4094.";
  }
 leaf ce-vlan-cos-perservation {
  type boolean;
  description
   "CE vlan CoS preservation. PCP bits in the CE-VLAN tag of the egress
    frame are identical to those of the ingress frame that yielded this
   egress service frame.";
  }
 description
  "Grouping for service preservation.";
}

grouping site-mac-addr-limit {
 container mac-addr-limit {
  leaf mac-num-limit {
   type uint16;
   description
    "maximum number of MAC addresses learned from
     the subscriber for a single service instance.";
  }
  leaf time-interval {
   type uint32;
   units milliseconds;
   description
    "The aging time of the mac address.";
  }
  leaf action {
   type identityref {
   base mac-action;
   }
  description
   "specify the action when the upper limit is
    exceeded: drop the packet, flood the
    packet, or simply send a warning log message.";
  }
  description
   "Container of MAC-Addr limit configurations";
 }



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 description
  "Grouping for mac address limit";
}

grouping site-attachment-availability {
 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 Sites.";
   }



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  leaf pause {
   type control-mode;
   description
    "Pause protocol type applicable to all Sites.";
  }
  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
    "IEEE 802.x.";
  }
  leaf e-lmi {
   type control-mode;
   description
    "E-LMI.";
  }
  leaf lldp {
   type boolean;
   description
    "LLDP protocol type applicable to all sites.";
  }
  leaf ptp-peer-delay {
   type control-mode;
   description
    "PTP peer delay.";
  }
  leaf garp-mrp {
   type control-mode;
   description
    "GARP/MRP.";
  }
  description
   "Container of L2CP control configurations";
 }



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 description
  "Grouping for l2cp control.";
}

grouping site-bum {
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;
   description
    "the MAC address of the Multicast group.";
  }
  leaf port-lag-number {
   type uint32;
   description
    "the ports/LAGs belonging to the Multicast group.";
  }
  description



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   "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 site-mac-loop-prevention {
 container mac-loop-prevention {
  leaf frequency {
   type uint32;
   description
    "Frequency.";
   }
  leaf protection-type {
   type identityref {
   base loop-prevention-type;
   }
  description
   "Protection type.";
  }
  leaf number-retries {
   type uint32;



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   description
    "Number of retries.";
  }
  description
   "Container of MAC loop prevention.";
 }
 description
  "Grouping for MAC loop prevention.";
}

grouping ethernet-svc-oam-grouping {
 container oam {
  leaf md-name {
   type string;
   description
    "Maintenance domain name.";
  }
  leaf md-level {
   type uint8;
   description
    "Maintenance domain level.";
  }
  list cfm-802.1-ag {
   key "maid";
   uses cfm-802-grouping;
   description
    "List of 802.1ag CFM attributes";
   }
   uses y-1731;
   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.";
  }
 leaf group-color {
  type string;
  description
   "Group color associated with a particular VPN.";
 }



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 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.";
  }
  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 {



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    type identityref {
     base placement-diversity;
    }
   description
    "Diversity constraint type.";
    }
   container target {
    choice target-flavor {
     default id;
     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 {
       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.";
   }



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



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    "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, ATM, Frame
      Relay, IP Layer 2 Transport, Frame Relay DLCI,
      SONET/SDH,PPP.";
   }
  leaf strict {
   type boolean;
   default false;
   description
    "Define if the requested-type is a preference
     or a strict requirement.";
   }
  description
   "Container for requested type.";
   }
  leaf always-on {
   if-feature always-on;
   type boolean;
   default true;
   description
    "Request for an always on access type.
     For example.This could mean no Dial access type.";
    }
  leaf bearer-reference {
   if-feature bearer-reference;
   type string;
   description
    "This is an internal reference for the
     service provider.";
  }



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  description
   "Bearer specific parameters.
    To be augmented.";
  }
 description
  "Grouping to define physical properties of
   a site attachment.";
}

grouping site-vpn-attachment {
 container vpn-attachment {
  leaf attachment-device-id {
   type string;
   description
    "Identifier for the attachment device.";
    }
  container management {
    when "derived-from-or-self(../../../../management/type,"+
      "'l2vpn-svc:co-managed')" {
      description
       "Applicable only for co-managed device.";
     }
   leaf address-family {
    type identityref {
    base address-family;
    }
    description
     "Address family used for management.";
   }
   leaf address {
     when "(../address-family)" {
      description
       "If address-family is specified, then address should
        also be specified.If address-family is not specified,
        then address should also not be specified.";
        }
     type inet:ip-address;
     mandatory true;
     description
     "Management address.";
   }
   description
    "Management configuration.";
  }
  choice attachment-flavor {
    case vpn-id {
     leaf vpn-id {
      type leafref {



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       path "/l2vpn-svc/vpn-services"+
        "/vpn-service/vpn-id";
      }
      description
       "Reference to a L2VPN. Referencing a vpn-id provides
        an easy way to attach a particular logical access to
        a VPN. In this case, vpn-id must be configured.";
     }
     leaf site-role {
      type identityref {
       base site-role;
      }
      default any-to-any-role;
      description
       "Role of the site in the L2VPN. 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.";
     }
    }
    case vpn-policy-id {
     leaf vpn-policy-id {
      type leafref {
       path "../../../../"+
        "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-bandwidth {
  if-feature input-bw;
  list bandwidth {
   key "direction type";
   leaf direction{
    type identityref {



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    base bw-direction;
   }
   description
    "Indicate the bandwidth direction. It can be bandwidth download
     direction from the SP to the site or bandwidth upload direction
     from the site to the SP.";
   }
   leaf type {
    type identityref {
    base bw-type;
    }
    description
     "Bandwidth Type.";
   }
   leaf cos-id {
    type uint8;
    description
     "Identifier of Class of Service
      , indicated by DSCP or a CE-CLAN
      CoS(802.1p)value in the service frame.";
    }
   leaf vpn-id {
    type svc-id;
    description
     "Identifies the target VPN.";
   }
   leaf cir {
    type uint64;
    units bps;
    description
     "Committed Information Rate. The maximum number of
      bits that a port can receive or send during
      one-second over an interface.";
   }
   leaf cbs {
    type uint64;
    units bps;
    description
     "Committed Burst Size.CBS controls the bursty nature
      of the traffic. Traffic that does not use the configured
      CIR accumulates credits until the credits reach the
      configured CBS.";
    }
   leaf eir {
    type uint64;
    units bps;
    description
    "Excess Information Rate,i.e.,Excess frame delivery



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     allowed not subject to SLA.The traffic rate can be
     limited by eir.";
   }
   leaf ebs {
    type uint64;
    units bps;
    description
     "Excess Burst Size. The bandwidth available for burst
      traffic from the EBS is subject to the amount of
      bandwidth that is accumulated during periods when
      traffic allocated by the EIR policy is not used.";
   }
   leaf pir{
    type uint64;
    units bps;
    description
     "Peak Information Rate, i.e., maixmum frame delivery
      allowed.It is equal to or less than sum of cir
      and eir.";
   }
   leaf pbs {
    type uint64;
    units bps;
    description
    "Peak Burst Size. It is measured in bytes per second.";
   }
  description
   "List for bandwidth.";
  }
  description
   "From the customer site's perspective, the service
    input/out bandwidth of the connection or download/upload
    bandwidth from the SP/site to the site/SP.";
  }
  uses svc-mtu;
  description
   "Define basic service parameters for the site.";
}

grouping flow-definition {
 container match-flow {
  leaf dscp {
   type inet:dscp;
   description
    "DSCP value.";
  }
  leaf dot1q {
   type uint16;



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   description
    "802.1q matching. It is VLAN Tag added into frame.";
  }
  leaf pcp {
   type uint8{
    range "0 .. 7";
   }
   description
    "PCP value.";
 }
 leaf src-mac {
  type yang:mac-address;
  description
   "Source MAC";
  }
  leaf dst-mac {
   type yang:mac-address;
   description
   "Destination MAC.";
  }
  leaf color-type {
   type identityref {
   base color-type;
  }
  description
   "Color Types.";
  }
  leaf-list target-sites {
   if-feature target-sites;
   type svc-id;
   description
    "Identify a site as traffic destination.";
  }
  leaf any {
   type empty;
   description
    "Allow all.";
  }
  leaf vpn-id {
   type svc-id;
   description
    "Reference to the target VPN.";
  }
  description
   "Describe flow matching criteria.";
  }
  description
   "Flow definition based on criteria.";



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}

grouping site-service-qos-profile {
 container qos {
  if-feature qos;
   container qos-classification-policy {
    list rule {
     key id;
     ordered-by user;
     leaf id {
      type string;
      description
       "A description identifying qos classification
       policy rule.";
     }
     choice match-type {
      default match-flow;
      case match-flow {
        uses flow-definition;
      }
      case match-phy-port {
       leaf match-phy-port {
        type uint16;
        description
         "Defines the physical port
         to match.";
        }
      }
      case match-application {
       leaf match-application {
        type identityref {
        base customer-application;
        }
       description
        "Defines the application 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



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      "List of marking rules.";
    }
   description
    "Configuration of the traffic classification policy.";
  }
container qos-profile {
 choice qos-profile {
  description
   "Choice for QoS profile.
    Can be standard profile or customized profile.";
  case standard {
   description
    "Standard QoS profile.";
   leaf profile {
   type leafref {
      path "/l2vpn-svc/vpn-profiles/valid-provider-identifiers"+
           "/qos-profile-identifier/id";
    }
   description
    "QoS Profile to be used.";
   }
  }
 case custom {
  description
   "Customized QoS profile.";
  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 identityref {
     base qos-profile-direction;
     }
     default bidirection;
     description
      "The direction which QoS profile is applied to";
    }
    leaf policing {
     type identityref {
      base policing;
     }



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   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.";
    }
    container frame-delay {
     choice flavor {
      case lowest {
       leaf use-lowest-latency {
        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-lowest-jitter {
       type empty;
       description
        "The traffic class should use
         the lowest jitter path.";
      }



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     }
     case boundary {
      leaf delay-bound {
       type uint32;
       units usec;
       description
        "The traffic class should use
         a path with a defined maximum
         jitter.";
      }
     }
    description
     "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 decimal64 {
       fraction-digits 5;
       range "0..100";
        }
     units percent;
     mandatory true;
     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.";



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     }
     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
  "QoS configuration.";
 }
 description
  "This grouping defines QoS parameters
  for a site";
}

grouping site-service {
 container service {
  uses site-service-basic;
  uses site-service-qos-profile;
  uses site-service-mpls;
  description
   "Service parameters on the attachment.";
  }
 description
  "Grouping for Service parameters.";
}

grouping site-service-mpls {
 container carrierscarrier {
  if-feature carrierscarrier;
  leaf signalling-type {
   type identityref{
   base carrierscarrier-type;
   }
  description
   "Carrierscarrier";
  }
  description
   "Container for carrierscarrier";
  }



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  description
   "Grouping for carrierscarrier";
}

grouping site-network-access-service {
 container service {
  uses site-service-qos-profile;
  uses site-service-mpls;
  description
   "Container for service";
 }
 description
  "Grouping for service.";
}

grouping vpn-profile-cfg {
 container valid-provider-identifiers {
  list cloud-identifier {
   if-feature cloud-access;
   key id;
   leaf id {
    type string;
    description
     "Identification of cloud service.
      Local administration meaning.";
   }
   description
    "List for Cloud Identifiers.";
  }
  list qos-profile-identifier {
   key id;
   leaf id {
    type string;
    description
     "Identification of the QoS Profile to be used.
      Local administration meaning.";
   }
  description
   "List for QoS Profile Identifiers.";
  }
 nacm:default-deny-write;
 description
  "Container for Valid Provider Identifies.";
 }
 description
  "Grouping for VPN Profile configuration.";
}




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grouping site-network-access-top-level-cfg {
 leaf site-network-access-type {
  type identityref {
    base site-network-access-type;
  }
  default point-to-point;
  description
   "Describes the type of connection, e.g.,
    point-to-point or multipoint.";
  }
 choice location-flavor {
  case location {
   when "derived-from-or-self(../../management/type, "+
    "'l2vpn-svc:customer-managed')" {
    description
     "Applicable only for customer-managed device.";
   }
   leaf location-reference {
    type leafref {
     path "../../../locations/location/location-id";
    }
    description
     "Location of the site-network-access.";
   }
  }
  case device {
   when "derived-from-or-self(../../management/type, "+
    "'l2vpn-svc:provider-managed') or "+
    "derived-from-or-self(../../management/type, "+
    "'l2vpn-svc:co-managed')" {
    description
     "Applicable only for provider-managed
      or co-managed device.";
   }
   leaf device-reference {
    type leafref {
     path "../../../devices/device/device-id";
    }
    description
     "Identifier of CE to use.";
   }
  }
  mandatory true;
  description
   "Choice of how to describe the site's location.";
 }
 uses access-diversity;
 uses site-attachment-bearer;



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 uses site-attachment-ethernet-connection;
 uses site-attachment-availability;
 uses site-vpn-attachment;
 uses site-network-access-service;
 uses site-bum;
 uses site-mac-loop-prevention;
 uses site-acl;
 uses site-mac-addr-limit;
 description
  "Grouping for site network access top-level
   configuration.";
}

/* MAIN L2VPN SERVICE */
container l2vpn-svc {
 container vpn-profiles {
  uses vpn-profile-cfg;
  description
   "Container for VPN Profiles.";
 }
 container vpn-services {
  list vpn-service {
   key "vpn-id";
   leaf vpn-id {
    type svc-id;
    description
     "Defining a service id.";
  }
 leaf svc-type {
  type identityref {
  base service-type;
  }
 description
  "Service type.";
 }
 leaf customer-name {
  type string;
  description
   "Customer name.";
 }
 leaf svc-topo {
  type identityref {
  base vpn-topology;
  }
  description
   "Defining service topology, such as
    any-to-any,hub-spoke, etc.";
 }



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 uses vpn-service-cloud-access;
 uses vpn-service-multicast;
 uses vpn-extranet;
 uses svc-preservation-grouping;
 leaf carrierscarrier {
  if-feature carrierscarrier;
  type boolean;
  default false;
  description
   "The VPN is using CsC, and so MPLS
   is required.";
 }
 description
  "List of vpn services.";
 }
 description
  "Container for VPN services.";
}

/* SITE */
container sites {
 list site {
  key "site-id";
  leaf site-id {
   type string;
   description
    "Identifier of the site.";
  }
 uses site-vpn-flavor;
 uses site-device;
 uses customer-location-info;
 uses site-management;
 uses site-diversity;
 uses site-vpn-policy;
 uses site-service;
 uses site-bum;
 uses site-mac-loop-prevention;
 uses site-acl;
 uses operational-requirements-ops;

 container site-network-accesses {
  list site-network-access {
   key "network-access-id";
   leaf network-access-id {
    type string;
    description
     "Identifier of network access";
   }



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   leaf remote-carrier-name {
    when "derived-from-or-self(../../../site-vpn-flavor,"+
       "'l2vpn-svc:site-vpn-flavor-nni')" {
     description
      "Site type = site-vpn-flavor-nni";
    }
    type string;
    description
     "Remote carrier name.";
   }
   uses site-network-access-top-level-cfg;
   description
    "List of Site Network Accesses.";
  }
  description
   "Container of port configurations.";
 }
 description
  "List of sites.";
 }
 description
  "Container of site configurations.";
 }
 description
  "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 lowest NETCONF layer is
   the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH)[RFC6242] . The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC5246].

   The NETCONF access control model [RFC6536] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the



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   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

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

      The entries in the list above include the whole vpn service
      configurations which the customer subscribes, and indirectly
      create or modify the PE and CE device configurations.  Unexpected
      changes to these entries could lead to the service disruption and/
      or network misbehavior.

   o  /l2vpn-svc/sites/site

      The entries in the list above include the customer site
      configurations.  As above, unexpected changes to these entries
      could lead to the service disruption and/or network misbehavior.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

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

   o  /l2vpn-svc/sites/site

   The entries in the lists above include customer-proprietary or
   confidential information, e.g., customer-name, site location, what
   service the customer subscribes.

   The data model defines some security parameters that can be extended
   via augmentation as part of the customer service request; those
   parameters are described in Section 5.12 and Section 5.13.

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].





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11.  IANA Considerations

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


       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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://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,
              <https://www.rfc-editor.org/info/rfc4448>.

   [RFC4664]  Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer
              2 Virtual Private Networks (L2VPNs)", RFC 4664,
              DOI 10.17487/RFC4664, September 2006,
              <https://www.rfc-editor.org/info/rfc4664>.

   [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,
              <https://www.rfc-editor.org/info/rfc4761>.



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   [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,
              <https://www.rfc-editor.org/info/rfc4762>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

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

   [RFC6073]  Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
              Aissaoui, "Segmented Pseudowire", RFC 6073,
              DOI 10.17487/RFC6073, January 2011,
              <https://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,
              <https://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,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

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

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

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




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   [RFC7348]  Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
              eXtensible Local Area Network (VXLAN): A Framework for
              Overlaying Virtualized Layer 2 Networks over Layer 3
              Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
              <https://www.rfc-editor.org/info/rfc7348>.

   [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, <https://www.rfc-editor.org/info/rfc7432>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://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,
              <https://www.rfc-editor.org/info/rfc8049>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8214]  Boutros, S., Sajassi, A., Salam, S., Drake, J., and J.
              Rabadan, "Virtual Private Wire Service Support in Ethernet
              VPN", RFC 8214, DOI 10.17487/RFC8214, August 2017,
              <https://www.rfc-editor.org/info/rfc8214>.

12.2.  Informative References

   [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-03 (work in
              progress), October 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-07 (work in progress),
              October 2017.

   [I-D.ietf-opsawg-service-model-explained]
              Wu, Q., LIU, W., and A. Farrel, "Service Models
              Explained", draft-ietf-opsawg-service-model-explained-05
              (work in progress), October 2017.



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   [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,
              <https://www.rfc-editor.org/info/rfc6624>.

   [RFC8199]  Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module
              Classification", RFC 8199, DOI 10.17487/RFC8199, July
              2017, <https://www.rfc-editor.org/info/rfc8199>.

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

   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:



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   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.

   o  Reference Update.

   Changes in v-(03) include:

   o  Introduce additional terminology.

   o  Modify figure 5 to get consistent with RFC8049.

   o  Add end to end Multi-segment connectivity support and site-vpn-
      flavor-e2e attribute.

   o  Add usage example to explain how to use EVC and OVC.




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   o  Discuss applicability of this model to inter-provider support.

   o  Reduce redundant parameters related to encapsulation type and
      Ethernet type in the model.

   o  Clarify the relationship between guarantee-bandwidth-percent and
      CIR, EIR and PIR.

   o  Modify model structure for VPN service to make it consistent with
      the text in section 5.

   o  Remove Sub-inf parameter since it is similar to QinQ parameter.

   o  Add "direction" parameter for QoS profile.

   o  Update XML example and figure in section 5.16.

   Changes in v-(04) include:

   o  Remove EVC and OVC related attributes.

   o  Remove Metro-Network related attributes.

   o  Remove Customer Account Number attributes.

   o  Update L2VPN service Types.

   o  Remove load banlancing options since access-priority within
      availability can be used to support load balancing.

   o  Remove service protection attribute since we have site diversity
      attributes.

   o  Move SVC-MTU to service level.

   o  Move CVLAN to Service Mapping to Network Access Level.

   o  Add two new parameters under qos-classification-policy.

   o  Remove Security Container.

   o  Remove IPv4/IPv6 prefix filter from VPN policy.

   o  Add Delivery mode support at service level.

   Changes in v-(05) include:





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   o  Change type from 16-bit integer to string for the leaf id under
      "qos-classification-policy" container.

   o  Stick to using ordered-by user and remove inefficiency to map
      service model sequence number to device model sequence number.

   o  Remove mandating the use of deviations and add "if-feature target-
      sites" under the leaf-list target-sites in section 5.10.2.

   o  RFC2119 language changes on operation of the management system in
      Section 5.6,3rd paragraph and section 7.

   o  Fix incomplete description statements.

   o  Change the use of the absolute paths to the use of relative paths
      in the "must" statement or "path" statement for vpn-policy-id leaf
      node, management container, location leaf node, devices container,
      location case, location-reference leaf, device case, device-
      reference leaf to make configuration is only applicable to the
      current sites.

   o  Change "must" statement to "when" statement for management
      container device container.

   o  Define new grouping vpn-profile-cfg for all the identifiers
      provided by SP to the customer.  The identifiers include cloud-
      identifier, std-qos-profile.

   o  Add in the XPATH string representation and remove unqualified
      name.

   o  Remove redundant parameters in the cloud access.

   o  Add a few text to clarify what the site is in section 6.3.

   o  Add multi-filter and multi-VPN per entry support for VPN policy.

   o  Modify description for svc-bandwidth leaf to make it consistent
      with the text in section 5.10.1.

   o  Add text to clarify the way to achieve Per-VPN QoS policy.

   o  Change guaranteed-bw-percent data type from uint8 to decimal64.








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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



























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