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PBB-EVPN ISID-based C-MAC-Flush
draft-ietf-bess-pbb-evpn-isid-cmacflush-09

Document Type Active Internet-Draft (bess WG)
Authors Jorge Rabadan , Senthil Sathappan , Kiran Nagaraj , Masahiro Miyake , Taku Matsuda
Last updated 2024-01-29 (Latest revision 2023-10-23)
Replaces draft-snr-bess-pbb-evpn-isid-cmacflush
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Details
draft-ietf-bess-pbb-evpn-isid-cmacflush-09
BESS Workgroup                                           J. Rabadan, Ed.
Internet-Draft                                              S. Sathappan
Intended status: Standards Track                              K. Nagaraj
Expires: 25 April 2024                                             Nokia
                                                               M. Miyake
                                                              T. Matsuda
                                                                Softbank
                                                         23 October 2023

                    PBB-EVPN ISID-based C-MAC-Flush
               draft-ietf-bess-pbb-evpn-isid-cmacflush-09

Abstract

   Provider Backbone Bridging (PBB) can be combined with Ethernet
   Virtual Private Networks (EVPN) to deploy Ethernet Local Area Network
   (ELAN) services in large Multi-Protocol Label Switching (MPLS)
   networks.  That combination is what we refer to as PBB-EVPN.  Single-
   Active Multi-homing and per-I-SID (per Service Instance Identifier)
   Load-Balancing can be provided to access devices and aggregation
   networks.  In order to speed up the network convergence in case of
   failures on Single-Active Multi-Homed Ethernet Segments (ES), PBB-
   EVPN defines a flush mechanism for Customer MACs (C-MAC-flush) that
   works for different Ethernet Segment Backbone MAC (B-MAC) address
   allocation models.  This document complements those C-MAC-flush
   procedures for cases in which no PBB-EVPN Ethernet Segments are
   defined (the attachment circuit is associated to a zero Ethernet
   Segment Identifier) and a Service Instance Identifier based (I-SID-
   based) C-MAC-flush granularity is required.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on 25 April 2024.

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Copyright Notice

   Copyright (c) 2023 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 (https://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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology and Conventions . . . . . . . . . . . . . . .   5
   2.  Solution requirements . . . . . . . . . . . . . . . . . . . .   6
   3.  EVPN BGP Encoding for ISID-based C-MAC-flush  . . . . . . . .   7
   4.  Solution description  . . . . . . . . . . . . . . . . . . . .   8
     4.1.  ISID-based C-MAC-Flush activation procedures  . . . . . .   9
     4.2.  C-MAC-Flush generation  . . . . . . . . . . . . . . . . .   9
     4.3.  C-MAC-flush process upon receiving a CMAC-flush
           notification  . . . . . . . . . . . . . . . . . . . . . .  10
   5.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   [RFC7623] defines how Provider Backbone Bridging (PBB) can be
   combined with Ethernet Virtual Private Networks (EVPN) to deploy ELAN
   services in very large MPLS networks.  [RFC7623] also describes how
   Single-Active Multi-homing and per-I-SID Load-Balancing can be
   provided to access devices and aggregation networks.  When Access
   Ethernet/MPLS Networks exists,
   [I-D.ietf-bess-evpn-virtual-eth-segment] describes how virtual
   Ethernet Segments (ES) can be associated to a group of Ethernet
   Virtual Circuits (EVCs) or even Pseudowires (PWs).  In order to speed
   up the network convergence in case of failures on Single-Active
   Multi-Homed Ethernet Segments, [RFC7623] defines a Customer MAC flush

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   mechanism that works for different Ethernet Segment B-MAC address
   allocation models.

   In some cases, the administrative entities that manage the access
   devices or aggregation networks do not demand Multi-Homing Ethernet
   Segments (ES) from the PBB-EVPN provider, but simply multiple single-
   homed ES.  Single-homed ES use null ESIs, whereas multi-homed ES use
   non-null ESIs.  If case of using single-homed ES, the PBB-EVPN
   network is no longer aware of the redundancy offered by the access
   administrative entity.  Figure 1 shows an example where the PBB-EVPN
   network provides four different Attachment Circuits for I-SID1, with
   those Attachment Circuits not being part of any Ethernet Segment or
   virtual Ethernet Segment (therefore they are referred to as null
   virtual Ethernet Segment).

        <----G.8032--><--PBB-EVPN Network---><----MPLS---->
             Access          MPLS                Access
              Ring                               Network
        I-SID1    ESI +------+         +------+
        +----+    null| PE1  |---------| PE3  |
        |CE1 |--------|B-MAC1|         |B-MAC3| ESI null
        +----+  active|      |         |      |----+ PW
          |           +------+         +------+     \active
          |             |                 |          \  +----+
          |             |                 |           ==|CE3 |I-SID1
          |             |                 |          /  +----+
          |stb    ESI +------+         +------+     / PW
        +----+    null| PE2  |         | PE4  |----+ standby
        |CE2 |--------|B-MAC2|         |B-MAC4| ESI null
        +----+  active|      |---------|      |
        I-SID1        +------+         +------+

               Figure 1: PBB-EVPN and non-ES based redundancy

   In the example in Figure 1, CE1, CE2 and CE3 are attached to the same
   service, identified by I-SID1, in the PBB-EVPN PEs.  CE1 and CE2 are
   connected to the PEs via G.8032 Ethernet Ring Protection Switching,
   and their Attachment Circuits to PE1 and PE2 are represented by a
   port and VLAN identifier.  CE3 is dual-homed to PE3 and PE4 through
   an active-standby PW, and its Attachment Circuit to the PEs is
   represented by a PW.  Each of the four PEs uses a dedicated Backbone
   MAC address as source MAC address (B-MAC1, B-MAC2, B-MAC3 and B-MAC4,
   respectively) when encapsulating customer frames in PBB packets and
   forwarding those PBB packets to the remote PEs as per [RFC7623].
   There are no multi-homed Ethernet Segments defined in the PBB-EVPN
   network of the example, that is why the four Attachment Circuits in
   Figure 1 show the text "ESI null", which means the Ethernet Segment
   Identifier on those Attachment Circuits is zero.  Since there are no

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   multi-homed ES defined, the PEs keep their Attachment Circuits active
   as long as the physical connectivity is established and the CEs are
   responsible for managing the redundancy, avoiding loops and providing
   per-I-SID load balancing to the PBB-EVPN network.  Examples of CEs
   managing their own redundancy are described in [G.8032], or [RFC4762]
   for active/standby Pseudowires.

   For instance, in normal conditions, CE2 will block its link to CE1
   and CE3 will block its forwarding path to PE4.  In this situation, a
   failure in one of the redundant Attachment Circuits will trigger the
   CEs to start using their redundant paths, however those failures will
   not trigger any Customer MAC flush procedures in the PEs that
   implement [RFC7623], since the PEs are not using the PBB-EVPN multi-
   homing procedures.  For example:

   *  if the active PW from CE3 (to PE3) fails and the failure is due to
      the entire PE3 node failing, then the procedures in [RFC7623]
      guarantee that all the remote PEs flush all the Customer MACs
      associated with B-MAC3 (the B-MAC of PE3).  In this case, CE3
      detects the fault due to the PW going operationally down.

   *  however, if the active PW from CE3 (to PE3) fails (but PE3 is
      still operationally up), following the procedures in [RFC7623],
      neither PE3 nor PE4 issue a Customer MAC flush message and
      therefore the remote PEs will continue pointing at PE3's Backbone
      MAC to reach CE3's Customer MACs, until the Customer MACs age out
      in the I-SID1 forwarding tables.  In this case, PE3 may use any of
      the existing PW notifications so that CE3 switches the active PW
      to PE4.

   *  the same issue is exposed when the active PW from CE3 switches
      over from PE3 to PE4 due to a manual operation on CE3; that is,
      neither PE3 nor PE4 trigger any Customer MAC flush notification
      and the remote PEs continue sending the traffic to PE3 until the
      Customer MACs age out.

   [RFC7623] provides a Customer MAC flush solution based on a shared
   Backbone MAC update along with the MAC Mobility extended community
   where the sequence number is incremented.  However, the procedure is
   only used along with multi-homed Ethernet Segments.  Even if that
   procedure could be used for null Ethernet Segments, as in the example
   of Figure 1, the [RFC7623] Customer MAC flush procedure would result
   in unnecessary flushing of unaffected I-SIDs on the remote PEs, and
   subsequent flooding of unknown unicast traffic in the network.  For
   instance, in case CE3 switches its active PW over to PE4, a potential
   solution reusing the existing C-MAC Flush notifications in [RFC7623]
   could be for PE3 to issue an update for the MAC/IP Advertisement
   route of B-MAC3 with a higher sequence number.  However, this update

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   would have caused unnecessary Customer MAC flushing for all the
   I-SIDs attached to PE3 (supposing multiple I-SIDs in PE3), and not
   only I-SID1.

   This document describes an extension of the [RFC7623] Customer MAC
   flush procedures, so that in the above failure example, PE3 can
   trigger a Customer MAC flush notification that makes PE1, PE2 and PE4
   flush all the Customer MACs associated to PE3's B-MAC3 and (only)
   I-SID1.  In order to do so, this specification introduces the
   encoding of the I-SID in the MAC/IP Advertisement routes advertised
   for the B-MACs.  The Customer MAC flush procedure explained in this
   document is referred to as "PBB-EVPN I-SID-based C-MAC-flush" and can
   be used in PBB-EVPN networks with null or non-null (virtual) Ethernet
   Segments.

   This specification assumes that the reader is familiar with the
   procedures in [RFC7623].

1.1.  Terminology and Conventions

   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.

   AC: Attachment Circuit.

   B-MAC: Backbone MAC address.

   B-MAC/0 route: an EVPN MAC/IP Advertisement route that uses a B-MAC
   in the MAC address field and a zero Ethernet Tag ID.

   B-MAC/I-SID route: an EVPN MAC/IP Advertisement route that uses a
   B-MAC in the MAC address field and an I-SID in the Ethernet Tag
   field, and it is used to notify remote PEs about the required C-MAC-
   flush procedure for the C-MACs associated with the advertised B-MAC
   and I-SID.

   CE: Customer Edge router.

   C-MAC: Customer MAC address.

   ES, and ESI: Ethernet Segment and Ethernet Segment Identifier.

   EVI: EVPN Instance.

   EVPN: Ethernet Virtual Private Networks, as in [RFC7432].

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   G.8032: Ethernet Ring Protection [G.8032].

   I-SID: Service Instance Identifier.

   MAC-VRF: A Virtual Routing and Forwarding table for MAC addresses.

   PBB-EVPN: Provider-Backbone-Bridging and EVPN, as in [RFC7623].

   PE: Provider Edge router.

   Familiarity with the terminology in [RFC7623] is expected.

2.  Solution requirements

   The following requirements are followed by the C-MAC-flush solution
   described in this document:

   a.  The solution MUST prevent black-hole scenarios in case of
       failures on null ES ACs (Attachment Circuits not associated to
       ES, that is, their corresponding ESI is zero) when the access
       device/network is responsible for the redundancy.

   b.  This extension described in this document MUST work with Single-
       Active non-null ES and virtual ES, irrespective of the PE B-MAC
       address assignment (dedicated per-ES B-MAC or shared B-MAC, as in
       [RFC7623]).

   c.  In case of failure on the egress PE, the solution MUST provide a
       C-MAC-flush notification at B-MAC and I-SID granularity level.

   d.  The solution MUST provide a reliable C-MAC-flush notification in
       PBB-EVPN networks that use Route-Reflectors (RRs).  MAC flushing
       needs to be provided to all affected I-SIDs in spite of the BGP
       flush notification messages being aggregated at the RR.

   e.  The solution MUST coexist in [RFC7623] networks where there are
       PEs that do not support this specification.

   f.  The solution SHOULD be enabled/disabled by an administrative
       option on a per-PE and per-I-SID basis (as opposed to be always
       enabled for all the I-SIDs).

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3.  EVPN BGP Encoding for ISID-based C-MAC-flush

   The solution does not use any new BGP attributes but reuses the MAC
   Mobility extended community as an indication of C-MAC-flush (as in
   [RFC7623]) and encodes the I-SID in the Ethernet Tag field of the
   EVPN MAC/IP advertisement route.  As a reference, Figure 2 shows the
   MAC Mobility extended community and the EVPN MAC/IP advertisement
   route that are used specified in [RFC7432] and used in this document
   as a C-MAC-flush notification message.

   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Type=0x06     | Sub-Type=0x03 |   Flags       |   Reserved=0  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Sequence Number                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               +---------------------------------------+
               |  Route Distinguisher                  |
               +---------------------------------------+
               |  ESI = 0                              |
               +---------------------------------------+
               |  Ethernet Tag ID = I-SID              |
               +---------------------------------------+
               |  MAC Address Length = 48              |
               +---------------------------------------+
               |  B-MAC Address                        |
               +---------------------------------------+
               |  IP Address Length = 0                |
               +---------------------------------------+
               |  MPLS Label1                          |
               +---------------------------------------+

        Figure 2: CMAC-Flush notification encoding: BMAC/ISID route

   Where:

   *  The route's route distinguisher and route targets are the ones
      corresponding to its EVI.  Alternatively to the EVI's RT, the
      route MAY be tagged with an RT auto-derived from the Ethernet Tag
      (I-SID) instead.  [RFC7623] describes how the EVPN MAC/IP
      Advertisement routes can be advertised along with the EVI RT or an
      RT that is derived from the I-SID.

   *  The Ethernet Tag encodes the I-SID for which the PE that receives
      the route must flush the C-MACs upon reception of the route.

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   *  The MAC address field encodes the B-MAC Address for which the PE
      that receives the route must flush the C-MACs upon reception of
      the route.

   *  The MAC Mobility extended community is used as in [RFC7623], where
      an increment in the sequence number between two updates for the
      same B-MAC/I-SID will be interpreted as a C-MAC-flush notification
      for the corresponding B-MAC and I-SID.

   All the other fields are set and used as defined in [RFC7623].  This
   document will refer to this route as the B-MAC/I-SID route, as
   opposed to the EVPN MAC/IP Advertisement route used in [RFC7623] that
   contains a specific B-MAC, and the Ethernet Tag ID set to zero.  This
   document uses the term B-MAC/0 route to represent a B-MAC route
   advertised with Ethernet Tag ID = 0.

   Note that this B-MAC/I-SID route will be accepted and reflected by
   any [RFC7432] RR, since no new attributes or values are used.  A PE
   receiving the route will process the received B-MAC/I-SID update only
   in case of supporting the procedures described in this document.

4.  Solution description

   Figure 1 will be used in the description of the solution.  CE1, CE2
   and CE3 are connected to ACs associated to I-SID1, where no (Multi-
   Homed) Ethernet Segments have been enabled, and the ACs and PWs are
   in active or standby state as per Figure 1.

   Enabling or disabling I-SID-based C-MAC-flush SHOULD be an
   administrative choice on the system that MAY be configured per I-SID
   (I-Component, Service Instance Component), as opposed to being
   configured for all I-SIDs.  When enabled on a PE:

   a.  The PE will be able to generate B-MAC/I-SID routes as C-MAC-Flush
       notifications for the remote PEs.

   b.  The PE will be able to process B-MAC/I-SID routes received from
       remote PEs.

   The PE MUST follow the [RFC7623] procedures for C-MAC-flush.  This
   specification brings some additional procedures when I-SID-based C-
   MAC-flush is enabled.

   This C-MAC-flush specification is described in three sets of
   procedures:

   *  I-SID-based C-MAC-flush activation

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   *  C-MAC-flush notification generation upon AC failures

   *  C-MAC-flush process upon receiving a C-MAC-flush notification

4.1.  ISID-based C-MAC-Flush activation procedures

   The following behavior MUST be followed by the PBB-EVPN PEs following
   this specification.  Figure 1 is used as a reference.

   *  As in [RFC7623], each PE advertises a shared B-MAC in a B-MAC/0
      route (with B-MAC1, B-MAC2, B-MAC3 and B-MAC4 in the MAC address
      field, respectively).  This is the B-MAC that each PE will use as
      B-MAC SA (Source Address) when encapsulating the frames received
      on any local single-homed AC.  Each PE will import the received
      B-MAC/0 routes from the remote PEs and will install the B-MACs in
      its B-component (Backbone Component) MAC-VRF.  For instance, PE1
      will advertise B-MAC1/0 and will install B-MAC2, B-MAC3 and B-MAC4
      in its MAC-VRF.

   *  Assuming I-SID-based C-MAC-flush is activated for I-SID 1, the PEs
      will advertise the shared B-MAC with I-SID 1 encoded in the
      Ethernet Tag. That is, PE1 will advertise B-MAC1/1 and will
      receive B-MAC2/1, B-MAC3/1 and B-MAC4/1.  The receiving PEs MUST
      use these B-MAC/I-SID routes only for C-MAC-flush procedures and
      they MUST NOT be used them to add/withdraw any B-MAC entry in the
      MAC-VRFs.  As per [RFC7623], only B-MAC/0 routes can be used to
      add/withdraw B-MACs in the MAC-VRFs.

   *  The above procedure MAY also be used for dedicated B-MACs (B-MACs
      allocated per Ethernet Segment).

4.2.  C-MAC-Flush generation

   If, for instance, there is a failure on PE1's AC, PE1 will generate
   an update including B-MAC1/1 along with the MAC Mobility extended
   community where the Sequence Number has been incremented.  The
   reception of the B-MAC1/1 with an increment in the sequence number
   will trigger the C-MAC-flush procedures on the receiving PEs.

   *  An AC going operationally down MUST generate a B-MAC/I-SID with a
      higher Sequence Number.  If the AC going down makes the entire
      local I-SID go operationally down, the PE will withdraw the B-MAC/
      I-SID route for the I-SID.

   *  An AC going operationally up SHOULD NOT generate any B-MAC/I-SID
      update, unless it activates its corresponding I-SID, in which case
      the PE will advertise the B-MAC/I-SID route.

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   *  An AC receiving a G.8032 flush notification or a flush message in
      any other protocol from the access network MAY propagate it to the
      remote PEs by generating a B-MAC/I-SID route update with higher
      Sequence Number.

4.3.  C-MAC-flush process upon receiving a CMAC-flush notification

   A PE receiving a C-MAC-flush notification will follow these
   procedures:

   *  A received B-MAC/I-SID route (with non-zero I-SID) MUST NOT add/
      remove any B-MAC to/from the MAC-VRF.

   *  An update of a previously received B-MAC/I-SID route with an
      increment Sequence Number, MUST flush all the C-MACs associated to
      that I-SID and B-MAC.  C-MACs associated to the same I-SID but
      different B-MAC MUST NOT be flushed.

   *  A received B-MAC/I-SID withdraw (with non-zero I-SID) MUST flush
      all the C-MACs associated to that B-MAC and I-SID.

   Note that the C-MAC-flush procedures described in [RFC7623] for
   B-MAC/0 routes are still valid and a PE receiving [RFC7623] C-MAC-
   flush notification messages MUST observe the behavior specified in
   [RFC7623].

5.  Conclusions

   The I-SID-based C-MAC-flush solution described in this document has
   the following benefits:

   a.  The solution solves black-hole scenarios in case of failures on
       null ES ACs, since the C-MAC-flush procedures are independent of
       the Ethernet Segment definition.

   b.  This extension can also be used with Single-Active non-null ES
       and virtual ES, irrespective of the PE B-MAC address assignment
       (dedicated per-ES B-MAC or shared B-MAC).

   c.  It provides a C-MAC-flush notification at B-MAC and I-SID
       granularity level, therefore flushing a minimum number of C-MACs
       and reducing the amount of unknown unicast flooding in the
       network.

   d.  It provides a reliable C-MAC-flush notification in PBB-EVPN
       networks that use RRs.  RRs will propagate the C-MAC-flush
       notifications for all the affected I-SIDs and irrespective of the
       order in which the notifications make it to the RR.

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   e.  The solution can coexist in a network with systems supporting or
       not supporting this specification.  Non-supporting systems ignore
       the B-MAC/I-SID routes, however they still follow the C-MAC-flush
       procedures in [RFC7623].

6.  Security Considerations

   Security considerations described in [RFC7623] apply to this
   document.

   In addition, this document suggests additional procedures, that can
   be activated on a per I-SID basis, and generate additional EVPN MAC/
   IP Advertisement routes in the network.  The format of these
   additional EVPN MAC/IP Advertisement routes is backwards compatible
   with [RFC7623] procedures and should not create any issues on
   receiving PEs not following this specification, however, the
   additional routes may consume extra memory and processing resources
   on the receiving PEs.  Because of that, it is RECOMMENDED to activate
   this feature only when necessary (when multi-homed networks or
   devices are attached to the PBB-EVPN PEs), and not by default in any
   PBB-EVPN PE.

7.  IANA Considerations

   This document requests no actions from IANA.

8.  Acknowledgments

   The authors want to thank Vinod Prabhu, Sriram Venkateswaran, Laxmi
   Padakanti, Ranganathan Boovaraghavan for their review and
   contributions.

9.  Contributors

10.  References

10.1.  Normative References

   [RFC7623]  Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W.
              Henderickx, "Provider Backbone Bridging Combined with
              Ethernet VPN (PBB-EVPN)", RFC 7623, DOI 10.17487/RFC7623,
              September 2015, <https://www.rfc-editor.org/info/rfc7623>.

   [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>.

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   [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>.

   [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>.

10.2.  Informative References

   [I-D.ietf-bess-evpn-virtual-eth-segment]
              Sajassi, A., Brissette, P., Schell, R., Drake, J., and J.
              Rabadan, "EVPN Virtual Ethernet Segment", Work in
              Progress, Internet-Draft, draft-ietf-bess-evpn-virtual-
              eth-segment-14, 23 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bess-
              evpn-virtual-eth-segment-14>.

   [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>.

   [G.8032]   "Recommendation ITU-T G.8032/Y.1344, Ethernet ring
              protection switching", March 2020.

Authors' Addresses

   Jorge Rabadan (editor)
   Nokia
   520 Almanor Avenue
   Sunnyvale, CA 94085
   United States of America
   Email: jorge.rabadan@nokia.com

   Senthil Sathappan
   Nokia
   520 Almanor Avenue
   Sunnyvale, CA 94085
   United States of America
   Email: senthil.sathappan@nokia.com

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   Kiran Nagaraj
   Nokia
   520 Almanor Avenue
   Sunnyvale, CA 94085
   United States of America
   Email: kiran.nagaraj@nokia.com

   M. Miyake
   Softbank
   Email: masahiro.miyake@g.softbank.co.jp

   T. Matsuda
   Softbank
   Email: taku.matsuda@g.softbank.co.jp

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