7k vPC best practice with multiple line cards?

[dkraut]

I have a pair of 7k's that have a single line card with a 2 port vPC linked to a pair of 5k's, another 2 port vPC linked to the layer 3 VDC and a 4 port vPC used for peer link.  I recently added an additional line card to the 7k’s and want to add redundancy for the new line card.  Would it be best to simply remove one of the existing ports from each vPC on line card 1 and then include a port from the new line card?  For the peer link, my thought was to remove two ports from the existing port channel and then add back 2 ports from the new line card.  This way line card 1 and 2 will share the ports that make up the vPC’s instead of all of the vPC ports being on line card 1.  Does that make sense or is there a better way to implement line card redundancy after adding a new line card? 

Also, if I want to add some of the ports on line card 2 to the layer 3 VDC.  Can I run the allocate interface command without the fear of it removing any existing allocated ports?  I understand that the ports being moved/allocated to a different VDC will lose their current configuration.  I had a bad experience years ago using "switchport trunk vlan allowed" vs. "switchport trunk vlan allowed add" command so I just want to make sure the allocate interface doesn't require the "add" option!  :)

Thanks!      

[Suresh Vinayagam Subramanian]

Hi,

For adding new interface to port-channel:

1. you can shutdown the new physical interface and put all the configure as existing member interface.

2. add as port-channal member.

3. Unshut the physical interfaces (new interface- module 2).

4. Shutdown the physical interfaces (module 1) which you wanted to remove from the port-channel 

Moving interface from one VDC another VDC will erase the configuration on that  interface  . you could use allocate interface command to add new interface to the VDC but all the interface should be in same port group. Adding new interface to vdc will not affect existing interface configuration  .

HTH
Regards,
VS.Suresh.
*Plz rate the usefull posts *

[dkraut]

Thanks Suresh, is it best practice to spread the the vPC peer link ports across multiple line cards? or is it better to have all peer link ports all on a single line card? 

[Suresh Vinayagam Subramanian · Accepted solution]

Hi,

we should avoid use single linecard for peer link as incase of hardware issue then you would see big impact in vpc environment . 

so for better redundancy , please use different linecards.

HTH
Regards,
VS.Suresh.
*Plz rate the usefull posts *