vPC link migration from F1 to M1 card

[mahendra.raj]

Hi All..

I have question in vPC please help me here to understand.

There are 2 7Ks connected via vPC link and it has downstream vpc link to pair of 5Ks. the link between the 7K and 5K are connected using F1 cards. The requirement now is we have to migrate the 7k to 5K link from F1 card to M1 card. Is there a way to do this migration without downtime? like migrating the link in one switch at a time and keep the traffic passing on via second switch during this migration?

One of my friend told me that we can't have F1 card on one side and M1 card on other side in a VPC host port channel. Is that correct?

Please help me to understand.

Thanks in advance.
Mahendra

[Steve Fuller]

Hi Mehendra,

Your friend is correct in that a vPC peer link cannot be built using ports from an M1 and F1 card. All ports must belong to the same card type i.e., all F1 or all M1. As per the Recommendations for vPC Peer-Link Configuration section from Page 29 of the Design and Configuration Guide: Best Practices for Virtual Port Channels (vPC) on Cisco Nexus 7000 Series Switches.

vPC Peer-link can be formed with M1 ports on both sides (M1 to M1), or F1 ports on both sides (F1 to F1), or F2 ports on both sides (F2 to F2). It is mandatory that both sides of vPC peer-link are strictly identical.

As a consequence, it is not possible to mix F1 port on 1 side and M1 port on the other side (for instance).

Assuming all your devices are connected to your vPC domain with virtual port-channels, then you shouldn't have any down time. What will happen when you migrate the peer link is that the two Nexus 7000 will consider the event as a peer-link failure, and the secondary peer will shutdown the vPC ports and any SVI. The vPC ports and SVI on the primary peer will remain operational and so there should be little or no traffic loss.

The document is for Nexus 5000, but the failure scenario is discussed in the vPC Peer-Link Failure section of the Cisco NX-OS Software Virtual PortChannel: Fundamental Concepts 5.0 design guide.

Regards

[jkilleda]

Hello Mahendra,

VPC link migration from F1 to M1 card
A VPC peer-link mode of M1 interfaces on one side and of F2 interfaces on the other side is not supported , and without downtime of 10-15 mins you cannot migrate from M1 to F1 , however you can try different ways to minimize to downtime.

https://www.cisco.com/c/en/us/support/docs/switches/nexus-7000-series-switches/116424-technote-vpc-00.html