Nexus vpc question

[robolliger]

Hi all

We run two nexus 7000 in a vpc configuration. Now, we need to configure an additional VLAN on the switches.

Is there a problem with the consistency if I configure a additional VLAN on one nexus first. Or, in other words, is vpc going down in the meantime that I configure this additional VLAN?

Thanks and kind regards,

Roger

[muhamali]

Hi Roger,

Is the new VLAN going to be part of VPC? VPC consistency check is run to make sure that port-channel could be formed between the different ports. Allowed vlans on vpc member ports needs to be identical to form a port-channel. If it is not; consistency check will fail and vpc will not be established.

Further information on VPC is available here

http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/C07-572835-00_NX-OS_vPC_DG.pdf

Information about VPC Consistency parameters is available here

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/command/reference/rel_4_1/vpc_commands.html#wp1080078

Cisco's recommendation is to make any changes that could affect consistency check adversely be made during a maintenance window. I believe there is a feature coming that will allow for these changes to be more gracefull but it is not out yet.

[robolliger]

Hi

Thanks for the fast replay.

Yes, the new VLAN is part of a VPC. It would also be part of the peer-link.

I would follow your and Cisco's recommendation to make the change in the next maintenance window.

Thank you and have a nice day.

Best regards,

Roger

[andy.steere]

When adding a new vlan to an existing vPC, it's been my experience that it doesn't take anything down. It just won't add the new vlan to the vPC until its consistent on both sides.  (edit: at least with v5.1 and above... no promise for earlier code)

[robolliger]

Hi Andy

Thank you for your replay.

We plan it for the next maintenance windows. After that, I have personal exprience..

Best regards,

Roger

[muhamali · Accepted solution]

Hi Roger,

Do keep us posted. on your experience. Just FYI, if you are running any code older than 5.0(2)N(2)1 you will need to be mindful of CSCtj88849

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCtj88849

[robolliger]

Yes I will do it. The code should not be the problem, we run 5.0(3)N2(1)...