Which technology minimizes flooding for a legacy layer-2 application across a campus connected via layer-3?

Which technology minimizes flooding for a legacy layer-2 application across a campus connected via layer-3?

• A. GRE
• B. EVPN-VXLAN
• C. EoIP
• D. Static VXLAN

Answer: (B)

Extending a legacy layer-2 app over a campus that’s routed at Layer 3 benefits from an overlay that can carry L2 frames while avoiding unnecessary floods. EVPN-VXLAN does exactly this by moving MAC address learning into the control plane and distributing MAC reachability across all VXLAN Tunnel Endpoints. When a frame destined for a particular MAC arrives, the network uses the EVPN/MAC information to forward it only to the VTEPs that actually host that MAC, rather than broadcasting or flooding everywhere. This keeps broadcast, unknown unicast, and multicast traffic localized to the relevant parts of the fabric and dramatically reduces flooding over the Layer-3 core. Other options don’t provide the same scalable MAC learning across the whole campus. GRE and EoIP are tunnel methods that don’t inherently offer a scalable control-plane for MAC distribution, leading to more flooding or require complex configurations. Static VXLAN lacks dynamic MAC discovery, so it’s brittle and can’t efficiently minimize floods as endpoints move or as new devices appear.

Extending a legacy layer-2 app over a campus that’s routed at Layer 3 benefits from an overlay that can carry L2 frames while avoiding unnecessary floods. EVPN-VXLAN does exactly this by moving MAC address learning into the control plane and distributing MAC reachability across all VXLAN Tunnel Endpoints. When a frame destined for a particular MAC arrives, the network uses the EVPN/MAC information to forward it only to the VTEPs that actually host that MAC, rather than broadcasting or flooding everywhere. This keeps broadcast, unknown unicast, and multicast traffic localized to the relevant parts of the fabric and dramatically reduces flooding over the Layer-3 core.

Other options don’t provide the same scalable MAC learning across the whole campus. GRE and EoIP are tunnel methods that don’t inherently offer a scalable control-plane for MAC distribution, leading to more flooding or require complex configurations. Static VXLAN lacks dynamic MAC discovery, so it’s brittle and can’t efficiently minimize floods as endpoints move or as new devices appear.