VXLAN + EVPN in Campus Switching?

I recently received some Arista 720XP PoE Campus Switches a key component of Arista’s Cognitive Campus efforts. While reviewing the datasheet, noticed something I found interesting: VXLAN + EVPN support.

Detail of VXLAN + EVPN support from Arista 720XP Datasheet

For those unfamiliar with VXLAN & EVPN here are some resources to check out.

https://en.wikipedia.org/wiki/Virtual_Extensible_LAN

https://blog.ipspace.net/2018/05/what-is-evpn.html

TLDR; VXLAN is layer 2 Ethernet transport over a layer 3 tunneling encapsulation while EVPN is a BGP based control plane for layer 2 and layer 3 hosts to signal this transport.

It is interesting to have these features in a campus switching platform and got me thinking about the evolution of the campus. Many large scale campus environments that I have worked with over the years have a mix of Layer 2 and Layer 3 islands which can be complex and difficult to deploy, manage and integrate. VXLAN + EVPN can potentially make operating a large, complex network much easier by giving one the capability to build an Layer 3 core that can use VXLAN as a transport for Layer 2 across a campus. Couple with that with maturing network controllers and intent based systems then the potential is there to build seamless, scalable infrastructures. For some of the huge, technology debt laden campuses out there, relief may be coming to reduce the difficulties of managing these systems.

Though use of VXLAN + EVPN in the campus is not new with vendors like Cisco, Extreme and Juniper offering solutions in the past few years as well, uptake seems to be slow. I often find many network engineers are rarely familiar with VXLAN much less EVPN so I think it’s going to be a while before they really get traction. I also think the software management platforms will be key to obfuscate the complexity and it will take a while for those to mature as well.

I like where this is headed and can see a lot of value in it for network practitioners. That said, one should always weigh the trade offs and validate that the complexity is warranted. Introducing technologies like EVPN to an environment is not trivial and it is key to understand how to operationally handle it including ongoing management and troubleshooting of these technologies. As always, be sure to lab and really dig into how things work before deploying.

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