Remove VPC keepalive port for fiber testing.

[bruce.thornton]

I have a VPC KeepAlive link between two Nexus 7009, we are getting  these errors:

0 runts 0 giants 13758 CRC/FCS 0 no buffer
13758 input error 0 short frame 0 overrun 0 underrun 0 ignored

I want to have the fiber between the two closets tested. What is the impact of unplugging the link for testing.

[Christopher Hart]

Hi Bruce,

Bringing the vPC Peer-Keepalive link down will have no impact on data plane or control plane traffic flowing through either vPC peer so long as the vPC Peer-Link is up and functioning as normal. This is documented in the "vPC Peer Keepalive Link Failure" section of the Virtual Port Channel Operations document.

You can use the show vpc brief command to verify this - the "Peer status" field should show "peer adjacency formed ok" if the vPC Peer-Link is up and operational. An example from my lab is below:

N9K-1# show vpc brief 
<snip>
vPC domain id : 1 
Peer status : peer adjacency formed ok 
vPC keep-alive status : peer is alive

If the vPC Peer-Link is up and operational between both vPC peers, feel free to bring down the vPC Peer-Keepalive link and troubleshoot these CRC errors further by replacing Layer 1 components (fiber, transceivers, etc.)

I hope this helps - thank you!

-Christopher 

[Reza Sharifi]

As also Chris said it correctly, removing vPC keep-alive port has no operational impact.

HTH