Cisco Embraces VXLAN with BGP-EVPN

As with many things in life, one size does not fit all when it comes to enabling network agility. While Cisco has been positioning its Nexus 9000 data center switch as an Application Centric Infrastructure (ACI) platform, Cisco is now providing VXLAN with BGP-EVPN as an optional way to enable network agility.

Garry Kinghorn, Product Marketing Manager, Data Center Solutions Group at Cisco, explained to Enterprise Networking Planet that BGP-EVPN with VXLAN is important, since VXLAN as an overlay technology is a core element in a number of Software Defined Networking (SDN) topologies. VXLAN was first proposed as a networking standard back in 2011.

“VXLAN didn’t originally have a control plane as part of the original specification,” Kinghorn said. “So along with others, we’ve been working on an extension to VXLAN that will provide a control plane and enable large scale-outs.”

Kinghorn explained that EVPN (Ethernet Virtual Private Network) is a standard for multi-protocol address mapping. Cisco is using BGP (Border Gateway Protocol) as the routing protocol, along with EVPN, to enable a complete control plane for VXLAN. He added that the combination of BGP-EVPN with VXLAN can be used to define how the VXLAN tunnel endpoints map the MAC to IP address mappings for virtual machines.

“It’s a way of doing address lookups and having virtual tunnel endpoints look up their participation tables of VMs,” Kinghorn said. “Then BGP as the routing protocol, using the route reflector, brings the information out to all of the VXLAN endpoints so they are up to date with where each layer 2 MAC address VM is sitting on which IP address as they move through the data center.”

Kinghorn added that EVPN allows for multiple routing protocols, though for the new Nexus 9000 support, Cisco is leveraging BGP. EVPN could also be used as a control plane for other overlays like NVGRE, so it’s not exclusive to VXLAN. Cisco is starting with BGP EVPN support for the Nexus 9000 platform, but will offer support on the Nexus 7000 platform and ASR 9000 in the second quarter of 2015.

Cisco’s ACI leverages the APIC (Application Policy Infrastructure Controller) as its control plane, though it still uses VXLAN. Kinghorn said that ACI users would not use the BPG-EVPN option. The choice as to whether an organization would deploy a Nexus 9000 in ACI mode or in standalone mode is up to the individual organization, Klinghorn said.

Sean Michael Kerner is a senior editor at Enterprise Networking Planet and Follow him on Twitter @TechJournalist.

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