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Fex and VPC

I'm am new to the whole datacenter design and I've recently taken over a data center set up. I'm trying to determine if my vPCs and port-channels are set up correctly. I've attached a drawing of the network set up. It seems pretty straight forward:

NIC teamed server with each NIC going to a separate FEX.

The FEX are straight through to the 5596s.

Using LACP on the switches and servers.

NX-OS 5.0(3)

My questions are 1) Is the FEX number only locally significant to the 5596 it's attached to? Should this number be the same or different on each 5596 or does it not matter? I haven't been able to find anything specifiying what this is supposed to be for this setup.

2) How can I verify the vPCs/portchannels are working properly?

Doing a 'show vpc' shows up/success on both switches.

'show port-channel summary' shows my channel  as SU and my port as P.

Doing a 'show interface pXXX' shows my port-channel and vPC if I run the command on both 5596s but they each only show one member in the channel, which is the locally connected interface. I would think I'm supposed to see both interfaces channled together here.

If I take one interface down I don't get any messages on the other switch that the other side of the port-channel has dropped. It also seems like traffic isn't being equally distributed.

I hope this makes sense. I've been trying to figure this environment out for weeks. Just when I think I've got it, it doesn't act the way I'm expecting it to.

Everyone's tags (6)

Fex and VPC

1) It does not matter if you have same FEX number on both switches. However, This will be a problem when you decide to implement Enhanced vpC where both FEX connected to both 5596 and servers are also connected to both FEXes.

2) show vpc is perfact command to verify. Another usefull command is show vpc consistancy-paramenter vpc 1902. If you have port down on any switch then you will see consitency parameter failed here.


Fex and VPC

Thanks for the response Krun Shah. So I shouldn't expect to see any messages if one end of the vPC or port-channel goes down? Also I should only see one member in each end of the port-channel?

Cisco Employee

Fex and VPC

Hi Leslie

If one peer will go down - you'll se message on the second that the peer went down.

But from the end device perspective this will look like one port-channel member went down.