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