Strange VPC Nexus traffic

[from88]

hello,

We've and old pair of N9K-C9372PX-E (7.0(3)I7(8)) running Straight Through VPC with lots of FEX devices. We're planning to update it to nxos.9.3.12.bin.
Everything is prepared, but we found out that there're some strange traffic on VPC Peer-link. Usually this means that some customer traffic are going via that link because one of the server interfaces are down. But this time everything with the clients is OK. There're even no dynamic MAC addresses in on VPC Port-channel link. Seems like it's some kind on internal Nexus traffic. The counters doesnt identify it as a BUM traffic. We're afraid to do any kind of maintenance - because of that traffic. Any idea how to indetify whats is the source of the traffic ? The direction of the traffic is only one way from VPC primary > to VPC Secondary switch.

[MHM Cisco World]

Can you use ethanalyzer to check what type of traffic.

[from88]

Thanks, yes, but it shows only control plane traffic, and it doesnt show the source interface of the packet, or it does ?

[MHM Cisco World]

Control and data traffic can see in ethanalyzer.

If we can know IP or MAC we can know from where this traffic.

[from88]

the data traffic in ethanalyzer, really ?
The bad thing was that we didn't know the IP neither MAC.

 i think that old software running is buggy, with a help of SPAN we noticed that to one particular destination the traffic is comming via VPC link, even all the interfaces is UP.

Did shut/no shut on server interfaces - seems problem solved..