What is EVPN (Ethernet VPN)?
Why Interviewers Ask This
Senior Networking engineers are expected to reason about architecture, performance, and edge cases. This question separates mid-level from senior candidates by testing deep system-level understanding.
Answer
EVPN (Ethernet VPN) is a control plane technology standardized in RFC 7432 that uses BGP to distribute MAC and IP reachability information — replacing traditional flood-and-learn MAC learning. Originally designed for MPLS data planes, EVPN is now most commonly used with VXLAN as the data plane in modern data center fabrics. Benefits: MAC/IP mobility — when a VM moves, BGP withdraws the old MAC/IP route and advertises it from the new location; ARP suppression — local proxy ARP using BGP-learned MAC/IP mappings eliminates ARP flooding; Multi-homing — active-active redundancy for hosts connected to multiple switches (Ethernet Segment ID); Layer 3 routing between VXLANs using Distributed Anycast Gateway (same gateway IP/MAC on all leaf switches). EVPN is the dominant control plane for leaf-spine data center fabrics (Cisco ACI, Arista CloudVision, Juniper QFX, cumulus Linux). It enables scalable, automated network overlays for cloud-scale environments.
Pro Tip
Back up your answer with a specific project or situation. Saying 'In my last Networking project, I used this when...' immediately makes your answer more credible and memorable.