Weighted Multi-Path Procedures for EVPN All-Active Multi-Homing
draft-ietf-bess-evpn-unequal-lb-07

Document Type Active Internet-Draft (bess WG)
Authors Neeraj Malhotra  , Ali Sajassi  , Jorge Rabadan  , John Drake  , Avinash Lingala  , Samir Thoria 
Last updated 2020-10-14
Replaces draft-malhotra-bess-evpn-unequal-lb
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Send notices to Stephane Litkowski <slitkows.ietf@gmail.com>
BESS WorkGroup                                          N. Malhotra, Ed.
Internet-Draft                                                A. Sajassi
Intended status: Standards Track                           Cisco Systems
Expires: April 17, 2021                                       J. Rabadan
                                                                   Nokia
                                                                J. Drake
                                                                 Juniper
                                                              A. Lingala
                                                                     ATT
                                                               S. Thoria
                                                           Cisco Systems
                                                        October 14, 2020

    Weighted Multi-Path Procedures for EVPN All-Active Multi-Homing
                   draft-ietf-bess-evpn-unequal-lb-07

Abstract

   In an EVPN-IRB based network overlay, EVPN all-active multi-homing
   enables multi-homing for a CE device connected to two or more PEs via
   a LAG, such that bridged and routed traffic from remote PEs can be
   equally load balanced (ECMPed) across the multi-homing PEs.  This
   document defines extensions to EVPN procedures to optimally handle
   unequal access bandwidth distribution across a set of multi-homing
   PEs in order to:

   o  provide greater flexibility, with respect to adding or removing
      individual PE-CE links within the access LAG.

   o  handle PE-CE LAG member link failures that can result in unequal
      PE-CE access bandwidth across a set of multi-homing PEs.

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."

Malhotra, et al.         Expires April 17, 2021                 [Page 1]
Internet-Draft         EVPN Weighted Multi-Pathing          October 2020

   This Internet-Draft will expire on April 17, 2021.

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Requirements Language and Terminology . . . . . . . . . . . .   3
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  PE-CE Link Provisioning . . . . . . . . . . . . . . . . .   4
     2.2.  PE-CE Link Failures . . . . . . . . . . . . . . . . . . .   5
     2.3.  Design Requirement  . . . . . . . . . . . . . . . . . . .   6
   3.  Solution Overview . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Weighted Unicast Traffic Load-balancing . . . . . . . . . . .   7
     4.1.  Local PE Behavior . . . . . . . . . . . . . . . . . . . .   7
     4.2.  EVPN Link Bandwidth Extended Community  . . . . . . . . .   7
     4.3.  Remote PE Behavior  . . . . . . . . . . . . . . . . . . .   8
   5.  Weighted BUM Traffic Load-Sharing . . . . . . . . . . . . . .   9
     5.1.  The BW Capability in the DF Election Extended Community .   9
     5.2.  BW Capability and Default DF Election algorithm . . . . .  10
     5.3.  BW Capability and HRW DF Election algorithm (Type 1 and
           4)  . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
       5.3.1.  BW Increment  . . . . . . . . . . . . . . . . . . . .  11
       5.3.2.  HRW Hash Computations with BW Increment . . . . . . .  11
     5.4.  BW Capability and Preference DF Election algorithm  . . .  13
   6.  Cost-Benefit Tradeoff on Link Failures  . . . . . . . . . . .  13
   7.  Real-time Available Bandwidth . . . . . . . . . . . . . . . .  13
   8.  Routed EVPN Overlay . . . . . . . . . . . . . . . . . . . . .  14
   9.  EVPN-IRB Multi-homing With Non-EVPN routing . . . . . . . . .  14
   10. Operational Considerations  . . . . . . . . . . . . . . . . .  15
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  15
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