Technology for carrying Ethernet traffic over wide area networks
Ethernet VPN (EVPN) is a technology for carrying layer 2 Ethernet traffic as a virtual private network using wide area network protocols. EVPN technologies include Ethernet over MPLS and Ethernet over VXLAN.[1][2]
EVPN uses encapsulation methods to ensure efficient and scalable transmission of Ethernet traffic over MPLS or IP-based networks. The encapsulation encapsulates Ethernet frames within MPLS or VXLAN headers for transport.
MPLS Encapsulation
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:
