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EVPN Port-Active Redundancy Mode
draft-ietf-bess-evpn-mh-pa-08

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This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Patrice Brissette , Luc André Burdet , Bin Wen , Eddie Leyton , Jorge Rabadan
Last updated 2023-07-05 (Latest revision 2022-10-05)
Replaces draft-brissette-bess-evpn-mh-pa
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draft-ietf-bess-evpn-mh-pa-08
BESS Working Group                                     P. Brissette, Ed.
Internet-Draft                                           LA. Burdet, Ed.
Intended status: Standards Track                           Cisco Systems
Expires: 6 January 2024                                           B. Wen
                                                                 Comcast
                                                               E. Leyton
                                                        Verizon Wireless
                                                              J. Rabadan
                                                                   Nokia
                                                             5 July 2023

                    EVPN Port-Active Redundancy Mode
                     draft-ietf-bess-evpn-mh-pa-08

Abstract

   The Multi-Chassis Link Aggregation Group (MC-LAG) technology enables
   establishing a logical link-aggregation connection with a redundant
   group of independent nodes.  The purpose of multi-chassis LAG is to
   provide a solution to achieve higher network availability while
   providing different modes of sharing/balancing of traffic.  [RFC7432]
   defines EVPN-based MC-LAG with Single-active and All-active
   multi-homing redundancy modes.  This document expands on existing
   redundancy mechanisms supported by EVPN and introduces a new Port-
   Active redundancy mode.

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 6 January 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Multi-Chassis Link Aggregation  . . . . . . . . . . . . . . .   4
   3.  Port-Active Redundancy Mode . . . . . . . . . . . . . . . . .   4
     3.1.  Overall Advantages  . . . . . . . . . . . . . . . . . . .   4
     3.2.  Port-Active Redundancy Procedures . . . . . . . . . . . .   5
   4.  Designated Forwarder Algorithm to Elect per Port-Active PE  .   6
     4.1.  Capability Flag . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Modulo-based Algorithm  . . . . . . . . . . . . . . . . .   7
     4.3.  HRW Algorithm . . . . . . . . . . . . . . . . . . . . . .   7
     4.4.  Preference-based DF Election  . . . . . . . . . . . . . .   8
     4.5.  AC-Influenced DF Election . . . . . . . . . . . . . . . .   8
   5.  Convergence considerations  . . . . . . . . . . . . . . . . .   8
     5.1.  Primary / Backup per Ethernet-Segment . . . . . . . . . .   9
     5.2.  Backward Compatibility  . . . . . . . . . . . . . . . . .   9
   6.  Applicability . . . . . . . . . . . . . . . . . . . . . . . .  10
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   10. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  11
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     11.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   EVPN [RFC7432] defines the All-Active and Single-Active redundancy
   modes.  All-Active redundancy provides per-flow load-balancing for
   multi-homing, and Single-active redundancy provides service carving
   where only one of the PEs in a redundancy relationship is active per
   service.

   While these two multi-homing scenarios are most widely utilized in
   data center and service provider access networks, there are scenarios
   where an active/standby multi-homing at the interface level is useful
   and required.  The main consideration for this new mode of

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   load-balancing is the determinism of traffic forwarding through a
   specific interface rather than statistical per-flow load-balancing
   across multiple PEs providing multi-homing.  The determinism provided
   by active/standby multi-homing at the interface level is also
   required for certain QOS features to work.  While using this mode,
   customers also expect fast convergence during failure and recovery.

   This document defines the Port-Active redundancy mode as a new type
   of multi-homing in EVPN and describes how this new mode operates and
   is to be supported via EVPN.  A new type of load-balancing mode,
   Port-Active redundancy, is defined.  This document describes how the
   new load-balancing mode can be supported via EVPN.  The new mode may
   also be referred to as per-interface active/standby.

                    +-----+
                    | PE3 |
                    +-----+
                 +-----------+
                 |  MPLS/IP  |
                 |  CORE     |
                 +-----------+
               +-----+   +-----+
               | PE1 |   | PE2 |
               +-----+   +-----+
                  |         |
                  I1       I2
                    \     /
                     \   /
                     +---+
                     |CE1|
                     +---+

                         Figure 1: MC-LAG Topology

   Figure 1 shows an MC-LAG multi-homing topology where PE1 and PE2 are
   part of the same redundancy group providing multi-homing to CE1 via
   interfaces I1 and I2.  Interfaces I1 and I2 are members of a LAG
   running LACP protocol.  The core, shown as IP or MPLS enabled,
   provides a wide range of L2 and L3 services.  MC-LAG multi-homing
   functionality is decoupled from those services in the core and it
   focuses on providing multi-homing to the CE.  In Port-Active
   redundancy mode, only one of the two interfaces I1 or I2 would be in
   forwarding and the other interface will be in standby.  This also
   implies that all services on the aca tive interface are in active
   mode and all services on the standby interface operate in standby
   mode.

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1.1.  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.

2.  Multi-Chassis Link Aggregation

   When a CE is multi-homed to a set of PE nodes using the
   [IEEE.802.1AX_2014] Link Aggregation Control Protocol (LACP), the PEs
   must act as if they were a single LACP speaker for the Ethernet links
   to form and operate as a Link Aggregation Group (LAG).  To achieve
   this, the PEs connected to the same multi-homed CE must synchronize
   LACP configuration and operational data among them.  Interchassis
   Communication Protocol (ICCP) [RFC7275] has historically been used to
   achieve this.  EVPN in [RFC7432] describes the case where a CE is
   multihomed to multiple PE nodes, using a Link Aggregation Group (LAG)
   as a means to greatly simplify the procedure.  The simplification,
   however, comes with a few assumptions:

   *  a CE device connected to EVPN multi-homing PEs MUST have a single
      LAG with all its links connected to the EVPN multi-homing PEs in a
      redundancy group.

   *  identical LACP parameters MUST be configured on peering PEs such
      as system id, port priority, and port key.

   This document relies on proper LAG operation as in [RFC7432].
   Discrepancies from the list above are out of the scope of this
   document, as are LAG misconfiguration and miswiring detection across
   peering PEs.

3.  Port-Active Redundancy Mode

3.1.  Overall Advantages

   The use of Port-Active redundancy brings the following benefits to
   EVPN networks:

   a.  Open standards-based active/standby redundancy at the interface
       level which eliminates the need to run ICCP and LDP (e.g., they
       may be running VXLAN or SRv6 in the network).

   b.  Agnostic of underlay technology (MPLS, VXLAN, SRv6) and
       associated services (L2, L3, Bridging, E-LINE, etc).

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   c.  Provides a way to enable deterministic QOS over MC-LAG attachment
       circuits.

   d.  Fully compliant with [RFC7432], does not require any new protocol
       enhancement to existing EVPN RFCs.

   e.  Can leverage various DF election algorithms e.g. modulo, HRW,
       etc.

   f.  Replaces legacy MC-LAG ICCP-based solution, and offers the
       following additional benefits:

       *  Efficiently supports 1+N redundancy mode (with EVPN using BGP
          RR) whereas ICCP requires a full mesh of LDP sessions among
          PEs in the redundancy group.

       *  Fast convergence with mass-withdraw is possible with EVPN, no
          equivalent in ICCP.

3.2.  Port-Active Redundancy Procedures

   The following steps describe the proposed procedure with EVPN LAG to
   support Port-Active redundancy mode:

   a.  The Ethernet-Segment Identifier (ESI) MUST be assigned per access
       interface as described in [RFC7432], which may be auto-derived or
       manually assigned.  The access interface MAY be a Layer-2 or
       Layer-3 interface.  The usage of ESI over a Layer-3 interface is
       newly described in this document.

   b.  Ethernet-Segment (ES) MUST be configured in Port-Active
       redundancy mode on peering PEs for specific access interface.

   c.  Peering PEs MAY exchange only Ethernet-Segment (ES) route
       (Route Type-4) when ESI is configured on a Layer-3 interface.

   d.  PEs in the redundancy group leverage the DF election defined in
       [RFC8584] to determine which PE keeps the port in active mode and
       which one(s) keep it in standby mode.  While the DF election
       defined in [RFC8584] is per [ES, Ethernet Tag] granularity, the
       DF election is done per <ES> in Port-Active redundancy mode.  The
       details of this algorithm are described in Section 4.

   e.  DF router MUST keep corresponding access interface in up and
       forwarding active state for that Ethernet-Segment

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   f.  Non-DF routers will by default implement a bidirectional blocking
       scheme for all traffic in line with [RFC7432] Single-Active
       blocking scheme, albeit across all VLANs.

       *  Non-DF routers MAY bring and keep peering access interface
          attached to it in an operational down state.

       *  If the interface is running LACP protocol, then the non-DF PE
          MAY also set the LACP state to OOS (Out of Sync) as opposed to
          an interface down state.  This allows for better convergence
          on standby to active transition.

   g.  For EVPN-VPWS service, the usage of primary/backup bits of EVPN
       Layer 2 Attributes Extended Community [RFC8214] is highly
       recommended to achieve better convergence.

4.  Designated Forwarder Algorithm to Elect per Port-Active PE

   The ES routes, running in Port-Active redundancy mode, are advertised
   with the new Port Mode Load-Balancing capability in the DF Election
   Extended Community defined in [RFC8584].  Moreover, the ES associated
   with the port leverages the existing procedure of Single-Active, and
   signals Single-Active Multihomed site redundancy mode along with
   Ethernet-AD per-ES route (Section 7.5 of [RFC7432]).  Finally the ESI
   label-based split-horizon procedures in Section 8.3 of [RFC7432]
   should be used to avoid transient echo'ed packets when Layer-2
   circuits are involved.

   The various algorithms for DF Election are discussed in Sections 4.2
   to 4.5 for completeness even though the choice of algorithm in this
   solution doesn't affect complexity or performance as in other
   redundancy modes.

4.1.  Capability Flag

   [RFC8584] defines a DF Election extended community, and a Bitmap (2
   octets) field to encode "capabilities" to use with the DF election
   algorithm in the DF algorithm field:

   Bit 0:    D bit or 'Don't Preempt' bit, as explained in
             [I-D.ietf-bess-evpn-pref-df].

   Bit 1:    AC-DF Capability (AC-Influenced DF election), as explained
             in [RFC8584].

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                            1 1 1 1 1 1
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |D|A|     |P|                   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Figure 2: Amended Bitmap field in the DF Election Extended Community

   This document defines the following value and extends the Bitmap
   field:

   Bit 5:    Port Mode Designated Forwarder Election (P bit hereafter),
             determines that the DF-Algorithm should be modified to
             consider the port ES only and not the Ethernet Tags.

4.2.  Modulo-based Algorithm

   The default DF Election algorithm, or modulus-based algorithm as in
   [RFC7432] and updated by [RFC8584], is used here, at the granularity
   of ES only.  Given that ES-Import Route Target extended community may
   be auto-derived and directly inherits its auto-derived value from ESI
   bytes 1-6, many operators differentiate ESI primarily within these
   bytes.  As a result, bytes 3-6 are used to determine the designated
   forwarder using Modulo-based DF assignment, achieving good entropy
   during Modulo calculation across ESIs:
   Assuming a redundancy group of N PE nodes, the PE with ordinal i is
   the DF for an <EE> when (Es mod N) = i, where Es represents bytes 3-6
   of that ESI.

4.3.  HRW Algorithm

   Highest Random Weight (HRW) algorithm defined in [RFC8584] MAY also
   be used and signaled, and modified to operate at the granularity of
   <ES> rather than per <ES, VLAN>.

   Section 3.2 of [RFC8584] describes computing a 32-bit CRC over the
   concatenation of Ethernet Tag and ESI.  For Port-Active redundancy
   mode, the Ethernet Tag is simply omitted from the CRC computation.

   DF(Es) denotes the DF and BDF(Es) denote the BDF for the ESI es; Si
   is the IP address of PE i; and Weight is a function of Si, and Es.

   1.  DF(Es) = Si| Weight(Es, Si) >= Weight(Es, Sj), for all j.  In the
       case of a tie, choose the PE whose IP address is numerically the
       least.  Note that 0 <= i,j < number of PEs in the redundancy
       group.

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   2.  BDF(Es) = Sk| Weight(Es, Si) >= Weight(Es, Sk), and Weight(Es,
       Sk) >= Weight(Es, Sj).  In the case of a tie, choose the PE whose
       IP address is numerically the least.

   Where:

   *  DF(Es) is defined to be the address Si (index i) for which
      Weight(Es, Si) is the highest; 0 <= i < N-1.

   *  BDF(Es) is defined as that PE with address Sk for which the
      computed Weight is the next highest after the Weight of the DF.  j
      is the running index from 0 to N-1; i and k are selected values.

4.4.  Preference-based DF Election

   When the new capability 'Port Mode' is signaled, the algorithm is
   modified to consider the port only and not any associated Ethernet
   Tags.  Furthermore, the Port Mode capability MUST be compatible with
   the 'Don't Preempt' bit.  When an interface recovers, a peering PE
   signaling D bit will enable non-revertive behavior at the port level.

4.5.  AC-Influenced DF Election

   The AC-DF bit MUST be set to 0 when advertising Port Mode Designated
   Forwarder Election capability (P=1).  When an AC (sub-interface) goes
   down, it does not influence the DF election.  The peer's Ethernet A-D
   per EVI is ignored in all Port Mode DF-Election algorithms.

   Upon receiving the AC-DF bit set (A=1) from a remote PE, it MUST be
   ignored when performing Port Mode DF Election.

5.  Convergence considerations

   To improve the convergence, upon failure and recovery, when the Port-
   Active redundancy mode is used, some advanced synchronization between
   peering PEs may be required.  Port-Active is challenging in the sense
   that the "standby" port may be in a down state.  It takes some time
   to bring a "standby" port to an up state and settle the network.  For
   IRB and L3 services, ARP / ND cache may be synchronized.  Moreover,
   associated VRF tables may also be synchronized.  For L2 services, MAC
   table synchronization may be considered.

   Finally, for members of a LAG running LACP the ability to set the
   "standby" port in "out-of-sync" state a.k.a "warm-standby" can be
   leveraged.

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5.1.  Primary / Backup per Ethernet-Segment

   The EVPN Layer 2 Attributes Extended Community ("L2-Attr") defined in
   [RFC8214] SHOULD be advertised in the Ethernet A-D per ES route for
   fast convergence.

   Only the P and B bits of the Control Flags field in the L2-Attr
   Extended Community are relevant to this document, and only in the
   context of Ethernet A-D per ES routes:

   *  When advertised, the L2-Attr Extended Community SHALL have only P
      or B bits in the Control Flags field set, and all other bits and
      fields MUST be zero.

   *  A remote PE receiving the optional L2-Attr Extended Community in
      Ethernet A-D per ES routes SHALL consider only P and B bits and
      ignore other values.

   For L2-Attr Extended Community sent and received in Ethernet A-D
   per EVI routes used in [RFC8214], [RFC7432] and
   [I-D.ietf-bess-evpn-vpws-fxc]:

   *  P and B bits received SHOULD be considered overridden by "parent"
      bits when advertised in the Ethernet A-D per ES.

   *  Other fields and bits of the extended community are used according
      to the procedures of those documents.

5.2.  Backward Compatibility

   Implementations that comply with [RFC7432] or [RFC8214] only (i.e.,
   implementations that predate this specification) will not advertise
   the EVPN Layer 2 Attributes Extended Community in Ethernet A-D per ES
   routes.  That means that all remote PEs in the ES will not receive P
   and B bit per ES and will continue to receive and honour the P and B
   bits received in Ethernet A-D per EVI route(s).  Similarly, an
   implementation that complies with [RFC7432] or [RFC8214] only and
   that receives an L2-Attr Extended Community in Ethernet A-D per ES
   routes will ignore it and continue to use the default path resolution
   algorithm:

   *  The remote ESI Label Extended Community ([RFC7432]) signals
      Single-Active (Section 4)

   *  the remote MAC and/or Ethernet A-D per EVI routes are unchanged,
      and since the L2-Attr Extended Community in Ethernet A-D per ES
      route is ignored, the P and B bits in the L2-Attr Extended
      Community in Ethernet A-D per EVI routes are used.

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6.  Applicability

   A common deployment is to provide L2 or L3 service on the PEs
   providing multi-homing.  The services could be any L2 EVPN such as
   EVPN VPWS, EVPN [RFC7432], etc.  L3 service could be in a VPN context
   [RFC4364] or in a global routing context.  When a PE provides first
   hop routing, EVPN IRB could also be deployed on the PEs.  The
   mechanism defined in this document is used between the PEs providing
   L2 and/or L3 services, when active/standby redundancy at the
   interface level is desired.

   A possible alternate solution to the one described in this document
   is MC-LAG with ICCP [RFC7275] active-standby redundancy.  However,
   ICCP requires LDP to be enabled as a transport of ICCP messages.
   There are many scenarios where LDP is not required e.g. deployments
   with VXLAN or SRv6.  The solution defined in this document with EVPN
   does not mandate the need to use LDP or ICCP and is independent of
   the underlay encapsulation.

7.  IANA Considerations

   This document solicits the allocation of the following values from
   the "BGP Extended Communities" registry group :

   *  Bit 5 in the [RFC8584] DF Election Capabilities registry, "P bit -
      Port Mode Designated Forwarder Election".

8.  Security Considerations

   The same Security Considerations described in [RFC7432] and [RFC8584]
   are valid for this document.

   By introducing a new capability, a new requirement for unanimity (or
   lack thereof) between PEs is added.  Without consensus on the new DF
   election procedures and Port Mode, the DF election algorithm falls
   back to the default DF election as provided in [RFC8584] and
   [RFC7432].  This behavior could be exploited by an attacker that
   manages to modify the configuration of one PE in the ES so that the
   DF election algorithm and capabilities in all the PEs in the ES fall
   back to the default DF election.  If that is the case, the PEs will
   be exposed to the same unfair load balancing, service disruption, and
   possibly black-holing or duplicate traffic mentioned in those
   documents and their security sections.

9.  Acknowledgements

   The authors thank Anoop Ghanwani for his comments and suggestions and
   Stephane Litkowski for his careful review.

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10.  Contributors

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

   Ali Sajassi
   Cisco Systems
   United States of America
   Email: sajassi@cisco.com

   Samir Thoria
   Cisco Systems
   United States of America
   Email: sthoria@cisco.com

11.  References

11.1.  Normative References

   [I-D.ietf-bess-evpn-pref-df]
              Rabadan, J., Sathappan, S., Lin, W., Drake, J., and A.
              Sajassi, "Preference-based EVPN DF Election", Work in
              Progress, Internet-Draft, draft-ietf-bess-evpn-pref-df-10,
              2 September 2022, <https://datatracker.ietf.org/doc/html/
              draft-ietf-bess-evpn-pref-df-10>.

   [IEEE.802.1AX_2014]
              IEEE, "IEEE Standard for Local and metropolitan area
              networks -- Link Aggregation", IEEE 802.1AX-2014,
              DOI 10.1109/IEEESTD.2014.7055197, 24 December 2014,
              <http://ieeexplore.ieee.org/servlet/
              opac?punumber=6997981>.

   [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>.

   [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>.

   [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>.

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   [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>.

   [RFC8584]  Rabadan, J., Ed., Mohanty, S., Ed., Sajassi, A., Drake,
              J., Nagaraj, K., and S. Sathappan, "Framework for Ethernet
              VPN Designated Forwarder Election Extensibility",
              RFC 8584, DOI 10.17487/RFC8584, April 2019,
              <https://www.rfc-editor.org/info/rfc8584>.

11.2.  Informative References

   [I-D.ietf-bess-evpn-vpws-fxc]
              Sajassi, A., Brissette, P., Uttaro, J., Drake, J.,
              Boutros, S., and J. Rabadan, "EVPN VPWS Flexible Cross-
              Connect Service", Work in Progress, Internet-Draft, draft-
              ietf-bess-evpn-vpws-fxc-08, 24 October 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bess-
              evpn-vpws-fxc-08>.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <https://www.rfc-editor.org/info/rfc4364>.

   [RFC7275]  Martini, L., Salam, S., Sajassi, A., Bocci, M.,
              Matsushima, S., and T. Nadeau, "Inter-Chassis
              Communication Protocol for Layer 2 Virtual Private Network
              (L2VPN) Provider Edge (PE) Redundancy", RFC 7275,
              DOI 10.17487/RFC7275, June 2014,
              <https://www.rfc-editor.org/info/rfc7275>.

Authors' Addresses

   Patrice Brissette (editor)
   Cisco Systems
   Ottawa ON
   Canada
   Email: pbrisset@cisco.com

   Luc Andre Burdet (editor)
   Cisco Systems
   Canada
   Email: lburdet@cisco.com

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Internet-Draft      EVPN Port-Active Redundancy Mode           July 2023

   Bin Wen
   Comcast
   United States of America
   Email: Bin_Wen@comcast.com

   Edward Leyton
   Verizon Wireless
   United States of America
   Email: edward.leyton@verizonwireless.com

   Jorge Rabadan
   Nokia
   United States of America
   Email: jorge.rabadan@nokia.com

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