Technology for carrying Ethernet traffic over wide area networks
Ethernet VPN (EVPN ) is a technology for carrying layer 2Ethernet traffic as avirtual private network usingwide area network protocols. EVPN technologies include Ethernet overMultiprotocol Label Switching (MPLS) and Ethernet overVirtual Extensible LAN (VXLAN).[ 1] [ 2]
EVPN uses encapsulation methods to enhance the efficiency and scalability of Ethernet traffic over MPLS or IP-based networks. The Ethernet frames are encapsulated within MPLS or VXLANheaders for transport.
In MPLS-based EVPN, Ethernet frames are encapsulated with:
MPLS label stack: Each EVPN instance is associated with a unique label that helps in identifying the destination bridge domain.Control word (optional): Provides additional information for synchronization and alignment in certain scenarios.The encapsulated packet flow includes:
Original Ethernet frame MPLS labels Outer IP header (in case of IP/MPLS networks)EVPNs are covered by a number of Internet RFCs, including:
RFC 7209 – "Requirements for Ethernet VPN (EVPN), "[ 3] Informational. 7432 – "BGP MPLS-Based Ethernet VPN, "[ 4] Proposed Standard. 8317 – "Ethernet-Tree (E-Tree) Support in Ethernet VPN (EVPN) and Provider Backbone Bridging EVPN (PBB-EVPN), "[ 5] Proposed Standard. 8365 – "A Network Virtualization Overlay Solution Using Ethernet VPN (EVPN), "[ 6] Proposed Standard. 9161 – "Operational Aspects of Proxy ARP/ND in Ethernet Virtual Private Networks, "[ 7] Proposed Standard.
