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 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:
RFC7209–"Requirements for Ethernet VPN (EVPN),"[3]Informational.
