VLAN communication

[gcook0001]

We are setting up a test environment and I have a question to ensure it will work like we want.   We are going to create a router on the UCS.  On the LAN side of the router it will be vlan 401 and the UCS side it will be vlan 400.  I would like to have vlan 400 just exist on the UCS since all servers will be created on it.  Is this doable or does the UCS send all traffic through the FEXs regardless if the two servers on are located on the UCS on the same subnet.

Gord.

[Walter Dey · Accepted solution]

Hi Gord

I hope you are Aware of the following facts

- UCS fabric interconnects do L2 switching only

- if you have a VM with a vnic connected to fabric A on Vlan 10, sends traffic to another VM which has a vnic on fabric B also in Vlan 10 => traffic has to leave the UCS Domain on fabric interconnect A, and reentering on fabric interconnect B.

- therefore you Need a UCS Northbound L2 Vlan 10 path

- above is mandatory, even if you do multihoming, and connect all vnics eg. to fabric A resp B. In case of any Failover, you will endup with the above situation.

Hope that clarifies and answers your question: You cannot / should not have a isolated vlan in the UCS Domain.