Context Label for MPLS EVPN
draft-wang-bess-evpn-context-label-04

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Last updated 2020-08-20
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BESS WG                                                          Y. Wang
Internet-Draft                                                   B. Song
Intended status: Standards Track                         ZTE Corporation
Expires: 21 February 2021                                 20 August 2020

                      Context Label for MPLS EVPN
                 draft-wang-bess-evpn-context-label-04

Abstract

   EVPN is designed to provide a better VPLS service than [RFC4761] and
   [RFC4762], and EVPN indeed introduced many new features which
   couldn't be achieved in those old VPLS implementions.  But EVPN
   didn't inherit all features of old VPLS, and a few issues arises for
   EVPN only.

   Some of these issues can be imputed to the MP2P nature of EVPN
   labels.  The PW label in old VPLS is a label for P2P VC, so it
   contains more context than a identifier in dataplane for it's VSI
   instance.But the EVPN label just identifies it's VSI instnace and it
   can't stand for the ingress PE in dataplane.  So the following issues
   arises with MPLS EVPN service:

   *  MPLS EVPN statistics can't be done per ingress PE.

   *  MPLS EVPN can't support hub/spoke use case which the spoke PE can
      only connect to each other by the hub PE.

   *  MPLS EVPN can't support AR REPLICATOR.

   *  MPLS EVPN can't support anycast SR-MPLS tunnel on the SPE nodes.

   This document introduces a compound label stack to take advantage of
   both P2P VC and MP2P evpn labels.

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/.

Wang & Song             Expires 21 February 2021                [Page 1]
Internet-Draft             EVPN Context Label                August 2020

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
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   This Internet-Draft will expire on 21 February 2021.

Copyright Notice

   Copyright (c) 2020 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/
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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Terminology and Acronyms  . . . . . . . . . . . . . . . . . .   3
   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Using VC Label to Add Context Data to EVPN Flows  . . . . . .   6
     3.1.  The Shared Context VCs  . . . . . . . . . . . . . . . . .   6
     3.2.  The per-EVI Context VCs . . . . . . . . . . . . . . . . .   6
   4.  Context VC Signalling Procedures  . . . . . . . . . . . . . .   6
     4.1.  Construct Leaf A-D Route for IR . . . . . . . . . . . . .   7
       4.1.1.  Advertising Per-platform VC Label . . . . . . . . . .   7
       4.1.2.  Advertising Context-Specific VC label . . . . . . . .   7
       4.1.3.  CSL-Entry Extended Community  . . . . . . . . . . . .   8
     4.2.  The Sharing of Context VCs  . . . . . . . . . . . . . . .   9
       4.2.1.  Using Admin-EVI . . . . . . . . . . . . . . . . . . .   9
       4.2.2.  Using per-platform VC labels  . . . . . . . . . . . .  10
     4.3.  Establish Ingress Replication List by Leaf A-D Route  . .  10
     4.4.  Backward Compatibility  . . . . . . . . . . . . . . . . .  11
   5.  Solutions . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Solution for Source-Squelching in Hub-Spoke Scenarios . .  11
     5.2.  Solution for per ingress statistics . . . . . . . . . . .  13
     5.3.  Solution for AR REPLICATOR in MPLS EVPN . . . . . . . . .  14
     5.4.  Solution for anycast tunnel usage on SPE  . . . . . . . .  14
       5.4.1.  Control-plane . . . . . . . . . . . . . . . . . . . .  15
         5.4.1.1.  Downstream-CLS ID Extended Community  . . . . . .  15
         5.4.1.2.  Context-specific Label Swapping . . . . . . . . .  16
       5.4.2.  Data-plane  . . . . . . . . . . . . . . . . . . . . .  16
       5.4.3.  The Generating of Downstream-CLS ID EC on SPE . . . .  17

Wang & Song             Expires 21 February 2021                [Page 2]
Internet-Draft             EVPN Context Label                August 2020
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