Which encapsulation is used by EVPN-VXLAN overlays?

Which encapsulation is used by EVPN-VXLAN overlays?

• A. Encapsulated in UDP
• B. GRE
• C. IP in IP
• D. MPLS

Answer: (A)

EVPN-VXLAN overlays wrap the original Ethernet frame with a VXLAN header that carries a VNI, and this VXLAN packet is then carried inside a UDP/IP tunnel. Using UDP allows the overlay to traverse IP networks and supports multicast/flooding behavior across VTEPs, which is essential for distributing ARP, unknown unicast, and broadcast traffic within a VXLAN segment. The standard VXLAN encapsulation uses UDP (typically to port 4789), making UDP the correct encapsulation method for EVPN-VXLAN. GRE, IP-in-IP, or MPLS can be used in other tunneling scenarios, but they are not the standard transport for EVPN-VXLAN overlays.

EVPN-VXLAN overlays wrap the original Ethernet frame with a VXLAN header that carries a VNI, and this VXLAN packet is then carried inside a UDP/IP tunnel. Using UDP allows the overlay to traverse IP networks and supports multicast/flooding behavior across VTEPs, which is essential for distributing ARP, unknown unicast, and broadcast traffic within a VXLAN segment. The standard VXLAN encapsulation uses UDP (typically to port 4789), making UDP the correct encapsulation method for EVPN-VXLAN.

GRE, IP-in-IP, or MPLS can be used in other tunneling scenarios, but they are not the standard transport for EVPN-VXLAN overlays.