VLANs deleted on the Ethernet switch northbound of UCS

[Mohammed Hasaballa]

1018

some of the VLANs were deleted from N5K-1 and not -2

About 3 servers stayed up and didn't loose connectivity and some other servers lost connectivity .

the vPC links between the N5ks & UCS stayed up. how UCS can detect such failure in the northbound Ethernet switch?

[Walter Dey]

In general, all vlan's defined in a UCS domain, are trunked on all ethernet uplinks. If you delete some of the vlan's on the Northbound switch, UCS's assumption that it can send traffic on any uplink (portchannel) will fail, for those blades / service profiles / vnic's, which are are pinned to the uplinks with missing vlan's.

[Mohammed Hasaballa]

1036

Thanks Walter. that is why i am asking if there is any mechanism exist today to stop UCS from forwarding specific VLAN traffic to northbound switch which it doesn't have that VLAN? or if i have failed VLAN in the northbound Ethernet switch can the UCS be notified not to send traffic for that VLAN?

[Walter Dey]

I exclude disjoint vlans for a moment;

All vlans in a UCS domains have to be configured on the Northbound switches, see eg.

http://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/white_paper_c11-623265.html

Traffic between vlan's has to be routed, external of UCS, UCS fabric Interconnect only do L2 !

But there is another case, L2 only, where traffic has to exit UCS domain Northbound: one blade / vnic is connected to fabric A, talking to a blade / vnic which is connected to fabric B, both on same vlan.