A Proposal for Capacity-Aware Load Balancing in EVPN Multi-Homing

This article proposes a lightweight extension to RFC 7432 EVPN multi-homing behavior by introducing a new BGP Extended Community that advertises active link count alongside EVPN Type 4 Ethernet Segment routes. The goal is to enable remote Provider Edge routers to perform capacity-aware weighted ECMP instead of default equal-cost traffic splitting in asymmetric LAG environments. The piece explores how the proposal works operationally, its limitations around hashing and hardware support, alternati...