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vPC-HM Mac-pinnig



I have a doubt with running mac pinning. When traffic allocates a VM on an interface by pinning mac algorithm, traffic keeps coming out for that interface until the interface goes down or removed. When restoring the connection to the original interface, the traffic keeps coming out for the new interface.

If I have a lot of traffic and only two uplink interfaces, after falling one, all traffic goes through a single interface resulting in a loss of service in the VM by traffic congestion, although the interface is back online. Is this correct? Or is there a mechanism for manual or automatic balancing to distribute traffic between interfaces?

Thanks, in advance

2 Replies 2

Robert Burns
Cisco Employee
Cisco Employee

What version of 1000v are you running.  This used to be a problem, but I believe I remember seeing an enhancement (not sure if I filed it or not) but it involved the re-balancing of veths across uplinks when a new one was added.

I do know that older behavior did what you're seeing - however, any new vEths brought up, Vmotioned etc - they will always pin to the less used link until they were equal and then continue in a round robin fashion.

I'll check back and confirm.


Thanks for your quickly reply! The version is 4.2(1)SV2(1.1a).

Best Regards!

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