What is the role of BGP in data center fabrics with leaf-spine/EVPN?

• A. It serves as the control plane for reachability announcements between racks.
• B. It is used solely for external internet routing and not internal fabric.
• C. It provides end-to-end encryption for data plane.
• D. It replaces VLANs with VXLAN in the fabric.

Answer: (A)

In data center fabrics that use a leaf-spine design with EVPN, BGP acts as the control plane that distributes reachability information across all VTEPs. MP-BGP with EVPN carries MAC and IP reachability routes so each leaf learns where a destination MAC/IP can be reached and through which VTEP. This enables traffic to be forwarded over the VXLAN overlay without flooding, supporting scalable multi-tenant isolation and seamless VM mobility. When a host moves to a different leaf, EVPN routes are updated and forwarding decisions adapt accordingly, keeping traffic flowing efficiently.

This role isn’t about external internet routing, so internal fabric reachability is what BGP EVPN handles. It doesn’t provide data-plane encryption itself, which is a separate security layer. And VXLAN handles the overlay tunneling for layer-2 extension, while BGP EVPN provides the signaling that tells the network where endpoints live; it doesn’t replace VLANs with VXLAN.