Weighted Multi-Path Procedures for EVPN Multi-Homing

Ethernet VPN (EVPN) provides all-active multi-homing for Customer Equipment (CE) devices connected to multiple Provider Edge (PE) devices, enabling equal cost load balancing of both bridged and routed traffic across the set of multi-homing PEs. However, existing procedures implicitly assume equal access bandwidth distribution among the multi-homing PEs, which can constrain link additions or removals and may not handle unequal PE-CE link bandwidth following link failures. This document specifies extensions to EVPN procedures to support weighted multi-pathing in proportion to PE-CE link bandwidth or operator-defined weights, thereby providing greater flexibility and resilience in multi-homing deployments. The extensions include signaling mechanisms to distribute traffic across egress PEs based on relative bandwidth or weight, and enhancements to Broadcast, Unknown Unicast, and Multicast (BUM) designated forwarder (DF) election to achieve weighted DF distribution across the multi- homing PE set.