nexus 5k vpc

[suthomas1]

Hi,

We have a mac address from a server card that appears on both Nexus 5K switches on the same port.
It appears to be so due to the vpc , but it will be helpful if someone can elaborate on why the same mac appears on both switches. ( there is an L2 vpc between both nexus 5K's )

Thanks in advance.

[Reza Sharifi · Accepted solution]

Hi,

If the server is connected to a FEX and if the FEX is uplinked to both 5ks and if VPC is running between the 5ks, that is normal behavior.

HTH

[suthomas1]

Thanks,

so i believe, this arrangement aids in getting the server connection redundant with link failure even though the server has only one physical connection going to the fex's.

[Suresh Vinayagam Subramanian]

Hi Suthomas,

Its expected behavior in VPC environment . when one switch receive data packet through vpc then it will learn mac address and also send info to peer switch thr' peer link.

Thats how mac and other control plane information sync with two peer devices. Even one switch fails , other switch will have all the control plane information to forward the data packet .

From downstream point view , it will see one upstream switch thr' port-channel. 

HTH
Regards,
VS.Suresh.
*Plz rate the usefull posts *