Hello,
i have a pair of 3548-X in a vpc domain in one DC, and another pair of 3548-X in another vpc domain in another DC. i have all of them connected in a mesh.
i have 3 vlans basically in a RPVST+ spanning tree. all of the vlans have converged between the DCs, but only one VLAN has a problem, where mac adresses are not being sent between the DCs. they are only being exchanged locally inside the seperate vpc domains.
the trunks connecting the pairs are not in a VPC, just normal trunks. I even had them grouped in port channel and VPC'd but didnt matter.
Any idea why that would happen, and why only this vlan? i have even setup a vlan interface on each nexus and trying to ping across the DCs wont work, so it cant be anything related to the servers connectes to this vlan.
NOTE: the only difference with this vlan is have a port channel and VPC setup for the local server in each DC, where two access ports are teamed.
I can see that the a mac adress is being learned inside each port channel, and the port channel is marked as designated in spanning tree.
when looking at the spanning topology everything looks right, and it should be forwarding like the other vlans. I can follow the a loop free path and its blocking the trunks as expected.
EDIT:
i just recalled that this VLAN exist only on these two nexus pairs, and the other two VLANs have their root in other catalyst switches.
I have the same priority (default 32768) on all 4 nexuses on this VLAN. could that be the problem ? even though i can see a loop free topology?
EDIT 2: *SOLVED*
it was the default priority that caused yhis problem. I gave one pair 4096 value, and mac adresses started to fly.
