Weighted Multi-Path Procedures for EVPN All-Active Multi-Homing
draft-ietf-bess-evpn-unequal-lb-03
BESS Working Group N. Malhotra, Ed.
Internet-Draft A. Sajassi
Intended Status: Proposed Standard S. Thoria
Cisco
J. Rabadan
Nokia
J. Drake
Juniper
A. Lingala
AT&T
Expires: May 5, 2020 Nov 2, 2019
Weighted Multi-Path Procedures for EVPN All-Active Multi-Homing
draft-ietf-bess-evpn-unequal-lb-03
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 bundle, 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
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Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 PE CE Link Provisioning . . . . . . . . . . . . . . . . . . 5
1.2 PE CE Link Failures . . . . . . . . . . . . . . . . . . . . 6
1.3 Design Requirement . . . . . . . . . . . . . . . . . . . . . 7
1.4 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 7
2. Solution Overview . . . . . . . . . . . . . . . . . . . . . . . 8
3. Weighted Unicast Traffic Load-balancing . . . . . . . . . . . 8
3.1 LOCAL PE Behavior . . . . . . . . . . . . . . . . . . . . . 8
3.1 Link Bandwidth Extended Community . . . . . . . . . . . . . 8
3.2 REMOTE PE Behavior . . . . . . . . . . . . . . . . . . . . . 9
4. Weighted BUM Traffic Load-Sharing . . . . . . . . . . . . . . 10
4.1 The BW Capability in the DF Election Extended Community . . 10
4.2 BW Capability and Default DF Election algorithm . . . . . . 11
4.3 BW Capability and HRW DF Election algorithm (Type 1 and
4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3.1 BW Increment . . . . . . . . . . . . . . . . . . . . . . 11
4.3.2 HRW Hash Computations with BW Increment . . . . . . . . 12
4.3.3 Cost-Benefit Tradeoff on Link Failures . . . . . . . . . 13
4.4 BW Capability and Weighted HRW DF Election algorithm
Malhotra et al. Expires May 5, 2020 [Page 2]
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