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Versions: (draft-boutros-l2vpn-evpn-vpws) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 RFC 8214

INTERNET-DRAFT                                              Sami Boutros
Intended Status: Standard Track                                   VMware
                                                             Ali Sajassi
                                                             Samer Salam
                                                           Cisco Systems
                                                              John Drake
                                                        Juniper Networks
                                                              J. Rabadan
                                                                   Nokia

Expires: November 15, 2017                                  May 14, 2017


         Virtual Private Wire Service support in Ethernet VPN
                   draft-ietf-bess-evpn-vpws-14.txt

Abstract

   This document describes how Ethernet VPN (EVPN) can be used to
   support Virtual Private Wire Service (VPWS) in MPLS/IP networks. EVPN
   enables the following characteristics for VPWS: single-active as well
   as all-active multi-homing with flow-based load-balancing, eliminates
   the need for Pseudowire (PW) signaling, and provides fast protection
   convergence upon node or link failure.

Status of this Memo

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

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

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

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html


Copyright and License Notice



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

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



Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  4
   2 Service interface  . . . . . . . . . . . . . . . . . . . . . . .  6
     2.1 VLAN-Based Service Interface . . . . . . . . . . . . . . . .  6
     2.2 VLAN Bundle Service Interface  . . . . . . . . . . . . . . .  6
       2.2.1 Port-Based Service Interface . . . . . . . . . . . . . .  7
     2.3 VLAN-Aware Bundle Service Interface  . . . . . . . . . . . .  7
   3. BGP Extensions  . . . . . . . . . . . . . . . . . . . . . . . .  7
     3.1 EVPN Layer 2 attributes extended community . . . . . . . . .  7
   4 Operation  . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
   5 EVPN Comparison to PW Signaling  . . . . . . . . . . . . . . . . 11
   6 Failure Scenarios  . . . . . . . . . . . . . . . . . . . . . . . 11
     6.1 Single-Homed CEs . . . . . . . . . . . . . . . . . . . . . . 11
     6.2 Multi-Homed CEs  . . . . . . . . . . . . . . . . . . . . . . 12
   7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 12
   8 Security Considerations  . . . . . . . . . . . . . . . . . . . . 12
   9 IANA Considerations  . . . . . . . . . . . . . . . . . . . . . . 12
   10 References  . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     10.1 Normative References  . . . . . . . . . . . . . . . . . . . 13
     10.2  Informative References . . . . . . . . . . . . . . . . . . 13
   Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14












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1  Introduction

   This document describes how EVPN can be used to support VPWS in
   MPLS/IP networks. The use of EVPN mechanisms for VPWS (EVPN-VPWS)
   brings the benefits of EVPN to Point to Point (P2P) services. These
   benefits include single-active redundancy as well as all-active
   redundancy with flow-based load-balancing. Furthermore, the use of
   EVPN for VPWS eliminates the need for traditional way of PW signaling
   for P2P Ethernet services, as described in section 4.

   [RFC7432] provides the ability to forward customer traffic to/from a
   given customer Attachment Circuit (AC), without any Media Access
   Control (MAC) lookup. This capability is ideal in providing P2P
   services (aka VPWS services). [MEF] defines Ethernet Virtual Private
   Line (EVPL) service as P2P service between a pair of ACs (designated
   by VLANs) and Ethernet Private Line (EPL) service, in which all
   traffic flows are between a single pair of ports, that in EVPN
   terminology would mean a single pair of Ethernet Segments ES(es).
   EVPL can be considered as a VPWS with only two ACs. In delivering an
   EVPL service, the traffic forwarding capability of EVPN is based on
   the exchange of a pair of Ethernet Auto-discovery (A-D) routes;
   whereas, for more general VPWS as per [RFC4664], traffic forwarding
   capability of EVPN is based on the exchange of a group of Ethernet AD
   routes (one Ethernet AD route per AC/ES). In a VPWS service,  the
   traffic from an originating Ethernet Segment can be forwarded only to
   a single destination Ethernet Segment; hence, no MAC lookup is needed
   and the MPLS label associated with the per EVPN instance (EVI)
   Ethernet A-D route can be used in forwarding user traffic to the
   destination AC.

   For both EPL and EVPL services, a specific VPWS service instance is
   identified by a pair of per-EVI Ethernet A-D routes which together
   identify the VPWS service instance endpoints and the VPWS service
   instance. In the control plane the VPWS service instance is
   identified using the VPWS service instance identifiers advertised by
   each Provider Edge node (PE). In the data plane the value of the MPLS
   label advertised by one PE is used by the other PE to send traffic
   for that VPWS service instance. As with the Ethernet Tag in standard
   EVPN, the VPWS service instance identifier has uniqueness within an
   EVPN instance.

   For EVPN routes, the Ethernet Tag IDs are set to zero for Port-based,
   VLAN-based, and VLAN-bundle interface mode and set to non-zero
   Ethernet Tag IDs for VLAN-aware bundle mode. Conversely, for EVPN-
   VPWS, the Ethernet Tag ID in the Ethernet A-D route MUST be set to a
   non-zero value for all four service interface types.

   In terms of route advertisement and MPLS label lookup behavior, EVPN-



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   VPWS resembles the VLAN-aware bundle mode of [RFC7432] such that when
   a PE advertises per-EVI Ethernet A-D route, the VPWS service instance
   serves as a 32-bit normalized Ethernet Tag ID. The value of the MPLS
   label in this route represents both the EVI and the VPWS service
   instance, so that upon receiving an MPLS encapsulated packet, the
   disposition PE can identify the egress AC from the MPLS label and
   subsequently perform any required tag translation. For EVPL service,
   the Ethernet frames transported over an MPLS/IP network SHOULD remain
   tagged with the originating VLAN-ID (VID) and any VID translation
   MUST be performed at the disposition PE. For EPL service, the
   Ethernet frames are transported as is and the tags are not altered.

   The MPLS label value in the Ethernet A-D route can be set to the
   Virtual Extensible LAN (VXLAN) Network Identifier (VNI) for VXLAN
   encapsulation as per [RFC7348], and this VNI will have a local scope
   per PE and may also be equal to the VPWS service instance identifier
   set in the Ethernet A-D route. When using VXLAN encap, the BGP
   Encapsulation extended community is included in the Ethernet A-D
   route as described in [ietf-evpn-overlay]. The VXLAN VNI like the
   MPLS label that will be set in the tunnel header used to tunnel
   Ethernet packets from all the service interface types defined in
   section 2. The EVPN-VPWS techniques defined in this document has no
   dependency on the tunneling technology.


   The Ethernet Segment identifier encoded in the Ethernet A-D per-EVI
   route is not used to identify the service. However it can be used for
   flow-based load-balancing and mass withdraw functions as per the
   [RFC7432] baseline.

   As with standard EVPN, the Ethernet A-D per-ES route is used for fast
   convergence upon link or node failure. The Ethernet Segment route is
   used for auto-discovery of the PEs attached to a given multi-homed
   Customer Edge node (CE) and to synchronize state between them.


1.1  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

   EVPN: Ethernet VPN

   MAC: Media Access Control

   MPLS: Multi Protocol Label Switching.




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   OAM: Operations, Administration and Maintenance.

   PE: Provide Edge Node.

   ASBR: Autonomous System Border Router

   CE: Customer Edge device e.g., host or router or switch.

   EVPL: Ethernet Virtual Private Line.

   EPL: Ethernet Private Line.

   EP-LAN: Ethernet Private LAN.

   EVP-LAN: Ethernet Virtual Private LAN.

   S-VLAN: Service VLAN identifier.

   C-VLAN: Customer VLAN identifier.

   VID: VLAN-ID.

   VPWS: Virtual Private Wire Service.

   EVI: EVPN Instance.

   P2P: Point to Point.

   VXLAN: Virtual Extensible LAN.

   DF: Designated Forwarder.

   L2: Layer 2.

   MTU: Maximum Transmission Unit.

   eBGP: Exterior Border Gateway Protocol.

   iBGP: Internal Border Gateway Protocol.

   ES: Ethernet Segment on a PE refers to the link attached to it, this
   link can be part of a set of links attached to different PEs in multi
   homed cases, or could be a single link in single homed cases.

   ESI: Ethernet Segment Identifier.

   Single-Active Mode: When a device or a network is multi-homed to two
   or more PEs and when only a single PE in such redundancy group can



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   forward traffic to/from the multi-homed device or network for a given
   VLAN, then such multi-homing or redundancy is referred to as "Single-
   Active".

   All-Active: When a device is multi-homed to two or more PEs and when
   all PEs in such redundancy group can forward traffic to/from the
   multi-homed device for a given VLAN, then such multi-homing or
   redundancy is referred to as "All-Active".

   VPWS Service Instance: It is represented by a pair of EVPN service
   labels associated with a pair of endpoints. Each label is downstream
   assigned and advertised by the disposition PE through an Ethernet A-D
   per-EVI route. The downstream label identifies the endpoint on the
   disposition PE. A VPWS service instance can be associated with only
   one VPWS service identifier.


2 Service interface

2.1 VLAN-Based Service Interface

   With this service interface, a VPWS instance identifier corresponds
   to only a single VLAN on a specific interface.  Therefore, there is a
   one-to-one mapping between a VID on this interface and the VPWS
   service instance identifier. The PE provides the cross-connect
   functionality between an MPLS LSP identified by the VPWS service
   instance identifier and a specific <port,VLAN>. If the VLAN is
   represented by different VIDs on different PEs and different ES(es),
   (e.g., a different VID per Ethernet segment per PE), then each PE
   needs to perform VID translation for frames destined to its Ethernet
   segment.  In such scenarios, the Ethernet frames transported over an
   MPLS/IP network SHOULD remain tagged with the originating VID, and a
   VID translation MUST be supported in the data path and MUST be
   performed on the disposition PE.

2.2 VLAN Bundle Service Interface

   With this service interface, a VPWS service instance identifier
   corresponds to multiple VLANs on a specific interface. The PE
   provides the cross-connect functionality between the MPLS label
   identified by the VPWS service instance identifier and a group of
   VLANs on a specific interface. For this service interface, each VLAN
   is presented by a single VID which means no VLAN translation is
   allowed. The receiving PE, can direct the traffic based on EVPN label
   alone to a specific port. The transmitting PE can cross-connect
   traffic from a group of VLANs on a specific port to the MPLS label.
   The MPLS-encapsulated frames MUST remain tagged with the originating
   VID.



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2.2.1 Port-Based Service Interface

   This service interface is a special case of the VLAN bundle service
   interface, where all of the VLANs on the port are mapped to the same
   VPWS service instance identifier.  The procedures are identical to
   those described in Section 2.2.

2.3 VLAN-Aware Bundle Service Interface

   Contrary to EVPN, in EVPN-VPWS this service interface maps to a VLAN-
   based service interface (defined in section 2.1) and thus this
   service interface is not used in EVPN-VPWS.  In other words, if one
   tries to define data plane and control plane behavior for this
   service interface, one would realize that it is the same as that of
   VLAN-based service.

3. BGP Extensions


   This document specifies the use of the per-EVI Ethernet A-D route to
   signal VPWS services. The Ethernet Segment Identifier field is set to
   the customer ES and the Ethernet Tag ID 32-bit field MUST be set to
   the VPWS service instance identifier value. The VPWS service instance
   identifier value MAY be set to a 24-bit value and when a 24-bit value
   is used, it MUST be right aligned. For both EPL and EVPL services
   using a given VPWS service instance, the pair of PEs instantiating
   that VPWS service instance will each advertise a per-EVI Ethernet A-D
   route with its VPWS service instance identifier and will each be
   configured with the other PE's VPWS service instance identifier. When
   each PE has received the other PE's per-EVI Ethernet A-D route, the
   VPWS service instance is instantiated. It should be noted that the
   same VPWS service instance identifier may be configured on both PEs.

   The Route-Target (RT) extended community with which the per-EVI
   Ethernet A-D route is tagged identifies the EVPN instance in which
   the VPWS service instance is configured. It is the operator's choice
   as to how many and which VPWS service instances are configured in a
   given EVPN instance. However, a given EVPN instance MUST NOT be
   configured with both VPWS service instances and standard EVPN multi-
   point services.

3.1 EVPN Layer 2 attributes extended community

   This document defines a new extended community [RFC4360], to be
   included with per-EVI Ethernet A-D routes. This attribute is
   mandatory if multihoming is enabled.

        +------------------------------------+



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        |  Type(0x06)/Sub-type(0x04)(2 octet)|
        +------------------------------------+
        |  Control Flags  (2 octets)         |
        +------------------------------------+
        |  L2 MTU (2 octets)                 |
        +------------------------------------+
        |  Reserved (2 octets)               |
        +------------------------------------+

        Figure 1: EVPN Layer 2 attributes extended community

         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |   MBZ                   |C|P|B|  (MBZ = MUST Be Zero)
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 2: EVPN Layer 2 attributes Control Flags

     The following bits in the Control Flags are defined; the remaining
     bits MUST be set to zero when sending and MUST be ignored when
     receiving this community.

     Name   Meaning

     P      If set to 1 in multihoming single-active scenarios, it
            indicates that the advertising PE is the Primary PE.
            MUST be set to 1 for multihoming all-active scenarios by
            all active PE(s).

     B      If set to 1 in multihoming single-active scenarios, it
            indicates that the advertising PE is the Backup PE.

     C      If set to 1, a Control word [RFC4448] MUST be present
            when sending EVPN packets to this PE. It is recommended to
            include the control word in the absence of Entropy Label.


   L2 MTU (Maximum Transmission Unit) is a 2-octet value indicating the
   MTU in bytes.

   A received L2 MTU of zero means no MTU checking against local MTU is
   needed. A received non-zero MTU MUST be checked against local MTU and
   if there is a mismatch, the local PE MUST NOT add the remote PE as
   the EVPN destination for the corresponding VPWS service instance.

   The usage of the Per ES Ethernet A-D route is unchanged from its
   usage in [RFC7432], i.e., the "Single-Active" bit in the flags of the
   ESI Label extended community will indicate if single-active or all-



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   active redundancy is used for this ES.

   In multihoming scenarios, the B and P flags MUST be cleared. A PE
   that receives an update with both B and P flags set MUST treat the
   route as a withdrawal. If the PE receives a route with both B and P
   clear, it MUST treat the route as a withdrawal from the sender PE.

   In a multihoming all-active scenario, there is no Designated
   Forwarder (DF) election, and all the PEs in the ES that are active
   and ready to forward traffic to/from the CE will set the P Flag. A
   remote PE will do per-flow load-balancing to the PEs that set the P
   Flag for the same Ethernet Tag and ESI. The B Flag in control flags
   SHOULD NOT be set in the multihoming all-active scenario and MUST be
   ignored by receiving PE(s) if set.

   In multihoming single-active scenario for a given VPWS service
   instance, the DF election should result in the Primary-elected PE for
   the VPWS service instance advertising the P Flag set and the B Flag
   clear, the Backup elected PE should advertise the P Flag clear and
   the B Flag set, and the rest of the PEs in the same ES should signal
   both P and B Flags clear. When the primary PE/ES fails, the primary
   PE will withdraw the associated Ethernet A-D routes for the VPWS
   service instance from the remote PE and the remote PEs should then
   send traffic associated with the VPWS instance to the backup PE. DF
   re-election will happen between the PE(s) in the same ES, and there
   will be a newly elected primary PE and newly elected backup PE that
   will signal the P and B Flags as described. A remote PE SHOULD
   receive the P Flag set from only one Primary PE and the B Flag set
   from only one Backup PE. However during transient situations, a
   remote PE receiving a P Flag set from more than one PE will select
   the last advertising PE as the primary PE when forwarding traffic. A
   remote PE receiving a B Flag set from more than one PE will select
   the last advertising PE as the backup PE. A remote PE MUST receive P
   Flag set from at least one PE before forwarding traffic.

   If a network uses entropy labels per [RFC6790] then the C Flag MUST
   NOT be set and control word MUST NOT be used when sending EVPN-
   encapsulated packets over a P2P LSP.


4 Operation

   The following figure shows an example of a P2P service deployed with
   EVPN.
          Ethernet                                          Ethernet
          Native   |<--------- EVPN Instance ----------->|  Native
          Service  |                                     |  Service
           (AC)    |     |<-PSN1->|       |<-PSN2->|     |  (AC)



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             |     V     V        V       V        V     V  |
             |     +-----+      +-----+  +-----+   +-----+  |
      +----+ |     | PE1 |======|ASBR1|==|ASBR2|===| PE3 |  |    +----+
      |    |-------+-----+      +-----+  +-----+   +-----+-------|    |
      | CE1| |                                              |    |CE2 |
      |    |-------+-----+      +-----+  +-----+   +-----+-------|    |
      +----+ |     | PE2 |======|ASBR3|==|ASBR4|===| PE4 |  |    +----+
           ^       +-----+      +-----+  +-----+   +-----+          ^
           |   Provider Edge 1        ^        Provider Edge 2      |
           |                          |                             |
           |                          |                             |
           |              EVPN Inter-provider point                 |
           |                                                        |
           |<---------------- Emulated Service -------------------->|

                    Figure 3: EVPN-VPWS Deployment Model
   iBGP sessions are established between PE1, PE2, ASBR1 and ASBR3,
   possibly via a BGP route-reflector. Similarly, iBGP sessions are
   established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions are
   established among ASBR1, ASBR2, ASBR3, and ASBR4.

   All PEs and ASBRs are enabled for the EVPN SAFI and exchange per-EVI
   Ethernet A-D routes, one route per VPWS service instance.  For inter-
   AS option B, the ASBRs re-advertise these routes with the NEXT_HOP
   attribute set to their IP addresses as per [RFC4271]. The link
   between the CE and the PE is either a C-tagged or S-tagged interface,
   as described in [802.1Q], that can carry a single VLAN tag or two
   nested VLAN tags and it is configured as a trunk with multiple VLANs,
   one per VPWS service instance. It should be noted that the VLAN ID
   used by the customer at either end of a VPWS service instance to
   identify that service instance may be different and EVPN doesn't
   perform that translation between the two values. Rather, the MPLS
   label will identify the VPWS service instance and if translation is
   needed, it should be done by the Ethernet interface for each service.

   For single-homed CE, in an advertised per-EVI Ethernet A-D route the
   ESI field is set to 0 and the Ethernet Tag ID is set to the VPWS
   service instance identifier that identifies the EVPL or EPL service.

   For a multi-homed CE, in an advertised per-EVI Ethernet A-D route the
   ESI field is set to the CE's ESI and the Ethernet Tag ID is set to
   the VPWS service instance identifier, which MUST have the same value
   on all PEs attached to that ES. This allows an ingress PE in a
   multihoming all-active scenario to perform flow-based load-balancing
   of traffic flows to all of the PEs attached to that ES. In all cases
   traffic follows the transport paths, which may be asymmetric.

   The VPWS service instance identifier encoded in the Ethernet Tag ID



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   in an advertised per-EVI Ethernet A-D route MUST either be unique
   across all ASs, or an ASBR needs to perform a translation when the
   per-EVI Ethernet A-D route is re-advertised by the ASBR from one AS
   to the other AS.

   A per-ES Ethernet A-D route can be used for mass withdraw to withdraw
   all per-EVI Ethernet A-D routes associated with the multi-home site
   on a given PE.


5 EVPN Comparison to PW Signaling

   In EVPN, service endpoint discovery and label signaling are done
   concurrently using BGP. Whereas, with VPWS based on [RFC4448], label
   signaling is done via LDP and service endpoint discovery is either
   through manual provisioning or through BGP.

   In existing implementations of VPWS using pseudowires(PWs),
   redundancy is limited to single-active mode, while with EVPN
   implementation of VPWS both single-active and all-active redundancy
   modes can be supported.

   In existing implementations with PWs, backup PWs are not used to
   carry traffic, while with EVPN, traffic can be load-balanced among
   different PEs multi-homed to a single CE.

   Upon link or node failure, EVPN can trigger failover with the
   withdrawal of a single BGP route per EVPL service or multiple EVPL
   services, whereas with VPWS PW redundancy, the failover sequence
   requires exchange of two control plane messages: one message to
   deactivate the group of primary PWs and a second message to activate
   the group of backup PWs associated with the access link.

   Finally, EVPN may employ data plane egress link protection mechanisms
   not available in VPWS. This can be done by the primary PE (on local
   AC down) using the label advertised in the per-EVI Ethernet A-D route
   by the backup PE to encapsulate the traffic and direct it to the
   backup PE.

6 Failure Scenarios

   On a link or port failure between the CE and the PE for both single
   and multi-homed CEs, unlike [RFC7432] the PE MUST withdraw all the
   associated Ethernet A-D routes for the VPWS service instances on the
   failed port or link.

6.1 Single-Homed CEs




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   Unlike [RFC7432],  EVPN-VPWS uses Ethernet A-D route advertisements
   for single-homed Ethernet Segments. Therefore, upon a link/port
   failure of this single-homed Ethernet Segment, the PE MUST withdraw
   the associated per-EVI Ethernet A-D routes.

6.2 Multi-Homed CEs

   For a faster convergence in multi-homed scenarios with either Single-
   Active Redundancy or All-active redundancy, a mass withdraw technique
   is used. A PE previously advertising a per-ES Ethernet A-D route, can
   withdraw this route by signaling to the remote PEs to switch all the
   VPWS service instances associated with this multi-homed ES to the
   backup PE.

7 Acknowledgements

   The authors would like to acknowledge Jeffrey Zhang, Wen Lin, Nitin
   Singh, Senthil Sathappan, Vinod Prabhu, Himanshu Shah, Iftekhar
   Hussain, Alvaro Retana and Acee Lindem for their feedback and
   contributions to this document.

8 Security Considerations

   The mechanisms in this document use EVPN control plane as defined in
   [RFC7432]. Security considerations described in [RFC7432] are equally
   applicable.

   This document uses MPLS and IP-based tunnel technologies to support
   data plane transport. Security considerations described in [RFC7432]
   and in [ietf-evpn-overlay] are equally applicable.

9 IANA Considerations

   IANA has allocated the following EVPN Extended Community sub-type:
   SUB-TYPE VALUE     NAME                        Reference
         0x04         EVPN Layer 2 Attributes     [RFCXXXX]

   This document creates a registry called "EVPN Layer 2 Attributes
   Control Flags". New registrations will be made through the "RFC
   Required" procedure defined in [RFC5226].

   Initial registrations are as follows:

     P      Advertising PE is the Primary PE.
     B      Advertising PE is the Backup PE.
     C      Control word [RFC4448] MUST be present.

10 References



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10.1 Normative References

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

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

   [RFC4448]  Martini, L., Rosen, E., El-Aawar, N., and G. Heron,
   "Encapsulation Methods for Transport of Ethernet over MPLS Networks",
   RFC 4448, April 2006.

   [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and L.
   Yong, "The Use of Entropy Labels in MPLS Forwarding", November 2012.

   [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border
   Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006, <http://www.rfc-
   editor.org/info/rfc4271>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
   Communities Attribute", RFC 4360, February 2006, <http://www.rfc-
   editor.org/info/rfc4360>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
   IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008,
   <http://www.rfc-editor.org/info/rfc5226>.

   [RFC7348] Mahalingam, M., et al, "VXLAN: A Framework for Overlaying
   Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, August
   2014

10.2  Informative References

   [MEF] Metro Ethernet Forum, "Ethernet Services Definitions - Phase
   2", Technical Specification MEF 6.1, April 2008,
   https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_6.1.pdf

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

   [ietf-evpn-overlay] Sajassi-Drake et al., "A Network Virtualization
   Overlay Solution using EVPN", draft-ietf-bess-evpn-overlay-07.txt,
   work in progress, December, 2016




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Contributors

   In addition to the authors listed on the front page, the following
   co-authors have also contributed to this document:

   Daniel Voyer Bell Canada

Authors' Addresses


   Sami Boutros
   VMware, Inc.
   Email: sboutros@vmware.com

   Ali Sajassi
   Cisco
   Email: sajassi@cisco.com

   Samer Salam
   Cisco
   Email: ssalam@cisco.com

   John Drake
   Juniper Networks
   Email: jdrake@juniper.net

   Jeff Tantsura
   Individual
   Email: jefftant@gmail.com

   Dirk Steinberg
   Steinberg Consulting
   Email: dws@steinbergnet.net

   Patrice Brissette
   Cisco
   Email: pbrisset@cisco.com

   Thomas Beckhaus
   Deutsche Telecom
   Email: Thomas.Beckhaus@telekom.de

   Jorge Rabadan
   Nokia
   Email: jorge.rabadan@nokia.com

   Ryan Bickhart
   Juniper Networks



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   Email: rbickhart@juniper.net


















































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