EVPN L3-Optimized IRB

Ethernet VPN Integrated Routing and Bridging (EVPN-IRB) provides dynamic and efficient intra and inter-subnet connectivity among Tenant Systems and end devices while maintaining very flexible multihoming capabilities. This document describes how EVPN-IRB can be optimized for IP hosts and devices such that PE devices only maintain MAC addresses for locally-connected IP hosts, thus improving MAC scalability of customer bridges and PE devices significantly. This document describes how such optimization is acheived while still supporting host moblity which is one of the fundamental features in EVPN and EVPN-IRB. With such optimization PE devices perform routing for both intra and inter-subnet traffic which results in some some caveats that operators and service providers need to be fully aware of.