VSS domain ID has to be unique in a Layer 2 domain?

[gwhuang5398]

I have 3 pairs of 4500X switches. Each pair will be converted into a VSS domain. The 3 VSS will have trunks in between. My question is when I convert devices into VSS, do I have to configure "switch virtual domain 1", "switch virtual domain 2", and "switch virtual domain 3" or just "switch virtual domain 1" for all pairs if the domain ID only has local meaning?

Thanks a lot

[Reza Sharifi]

That is correct.  Each VSS domain id needs to be unique.

HTH

[rakeshvelagala]

Hi Reza,

One of my customers config is as below from show run. They have 2 switches in VSS. (switch1 and switch2).

Customer Platform is 4500x

 switch virtual domain 1
 switch mode virtual
 switch 1 priority 210
 mac-address use-virtual

Switch 1 recently failed. Can you please advise how can I check if there is a different domain domain ID? 

According to the aove discussion, if we use mac-address use-virtual, we need to have different domain id.

Thank

[rakeshvelagala]

Thanks. I got the answer.

[Jon Marshall · Accepted solution]

If you are going to use the "mac-address use-virtual" which Cisco recommend you do then you need a different domain ID per switch pair because the switches use the domain ID in generating the virtual mac address.

See this link for details -

http://www.labminutes.com/blog/2012/12/cisco-6500-vss-domain-id-and-virtual-mac-address

it is for the 6500 but it applies to VSS in general as there was thread on 4500s with the same issue a while back.

Jon

[gwhuang5398]

Greatly appreciated