Interconnecting EVPN and IPVPN Domains

Ethernet Virtual Private Network (EVPN) provides a unified BGP control plane for both intra- and inter-subnet forwarding within tenant networks. When a tenant network spans multiple domains, including any combination of EVPN and IPVPN domains, it becomes necessary to define the interworking mechanisms among these BGP domains (EVPN and IPVPN) to ensure seamless end-to-end tenant connectivity. This document defines these interworking procedures. In addition, this document defines a new BGP Path Attribute, referred to as D-PATH (Domain PATH), which provides loop prevention for gateway nodes by protecting against control plane loops. The introduction of D-PATH modifies the BGP best path selection process for Multiprotocol BGP inter-subnet forwarding routes of SAFI 128 (IPVPN) and SAFI 70 (EVPN).