EVPN Campus Fabric (Catalyst9k)

[Michael Kiessling]

Hi all,

first of all, has anyone deployed a EVPN fabric in a campus with cat9500 switches yet?

I would like to deploy an EVPN fabric within a three tier campus LAN. The fabric will be build up

between core and distribution (all cat9500 with advantage license). The access switches will

just be simple layer 2 switches (not shown in the diagram):

RR = BGP route reflector / R = BGP router

One question I'm struggling with is if the distribution switches should be stand alone switches or a VSS (if supported).

In above example I would have two spines (the campus cores) and three leafs (3x two switches as VSS).

Any input if this would work or which design (VSS or no VSS) would be better is highly appreciated.

I'd also like to know if anyone has deloyed a EVPN fabric wit catalyst 9k switches at all.

Many thanks.

Best regards

Michael

[Reza Sharifi]

Hi Michael,

According to table-16 in this link, both VXLAN/EVPN and StackWise virtual are supported when you are running "Network Advantage" license.

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9500-series-switches/nb-06-cat9500-ser-data-sheet-cte-en.html

I have not done this before, but I think if you can take advantage of StackWise virtual technology, the design would be much simpler because every 2 physical switches will logically become one, and so it is easier to manage the infrastructure.

HTH

[Michael Kiessling]

Hi Reza,

many thanks for your input. I think VSS has two benefits here, one is simplified management, as you mentioned, and one is multi-homing. The access switches need to be connected redundant to two separate chassis. AFAIK the Cat9k currently don't support ESI-LAG, so VSS is the only option.

Best regards,

Michael

[Reza Sharifi]

Hi Michael,

That is correct. If you don't use VSS or StackWise Virtual (as Cisco calls it these days), STP would block one of the uplinks in order to avoid loops on the network. So, I think VSS is the way to go. This way, it is easier to manage the environment with fewer boxes, STP simply runs in the background without blocking any ports, and also you will be using both chassis for packet forwarding.  

Good Luck!