MP-BGP EVPN Function in Cisco ACI Multi-Site
What is the function of MP-BGP EVPN in Cisco ACI Multi-Site?
Community Insight
The core trap is confusing the control plane's role in distributing external prefixes with its primary function of exchanging endpoint reachability information (MAC/IP) across sites.
This question examines the role of MP-BGP EVPN in Cisco ACI Multi-Site, specifically how it handles endpoint reachability and routing between geographically separate fabrics.
Many candidates select option C because BGP is traditionally associated with prefix distribution; however, in ACI Multi-Site, EVPN specifically focuses on Layer 2/3 endpoint learning rather than just static prefix exchange.
Community Discussion (1 comments)
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Expert Analysis
Why the Answer Is Correct
MP-BGP EVPN serves as the intersite control plane for Cisco ACI Multi-Site deployments. Its primary function is to exchange endpoint reachability information—specifically MAC and IP addresses—between the leaf switches of different sites. This allows endpoints in one site to be reachable from another without requiring full mesh connectivity or complex routing protocols between every site.Why the Other Options Are Wrong
Option C describes a general BGP function but misses the specific EVPN context of endpoint learning which is critical for multi-site overlay networking. Option A incorrectly suggests that spines exchange this information directly between sites; the exchange actually happens via the leaf-to-leaf or spine-to-spine tunnels established by the fabric, but the data originates from endpoint learning on leaves. Option D describes management plane connectivity, which is handled by HTTPS/REST APIs and not the data/control plane protocol MP-BGP.Community Comment Notes
As Mukiongi noted, the correct answer is A because MP-BGP EVPN acts as the intersite control plane exchanging endpoint reachability. The community consensus confirms that while BGP distributes routes, EVPN specifically handles the MAC/IP advertisement necessary for seamless multi-site mobility.Exam Strategy
Focus on the distinction between standard BGP prefix exchange and EVPN's specific role in advertising endpoint attributes (MAC/IP) for overlay networks. In Multi-Site scenarios, remember that EVPN enables Layer 2/3 extension across sites.
Frequently Asked Questions
Why isn't MP-BGP EVPN used to distribute external prefixes?
While BGP can distribute prefixes, EVPN in ACI Multi-Site is specifically optimized for exchanging endpoint MAC/IP reachability to enable seamless Layer 2/3 extension.
Does MP-BGP EVPN connect NDO and APIC?
No, NDO and APIC connectivity is managed via the management plane using HTTPS/REST APIs, not the data plane protocol MP-BGP.