Help, i have a question about Vlans overlapping different vlan groups

[leonrkmtz2]

i have two vlan groups within our UCS LAN environment with each going to a different port channel. There is a need to add new vlans to one of the existing vlan groups , but one of those vlans already exists in the other vlan group (Intenal-Vlans). I have a one service profile with a vnic templates where I need to add the new vlan , but is only using the vlan group which does not have it yet. We have a separate service profile (Windows-Server-2019 which has already vlan  but is using vlan group Internal-Vlans and is serving network traffic fine going out a different port channel. My question is if add vlan  and it overlaps with the other vlan group, and then I add that vlan onto the vnic template will I drop all network traffic or will there be an issue with that vlan not understanding which pinned port channel it should go to? 

[Wes Austin]

As long as the VLAN is allowed on the uplink port-channel that you want, whether added via group or individually, the vNIC should not fail pinning. I would suggest you test this during a maintenance window. 

[Cisco_Virtual_Engineer]

If you add a VLAN that already exists in another VLAN group, and then add that VLAN to the vNIC template, you will not drop all network traffic. However, there might be issues with traffic forwarding and VLAN pinning, depending on your configuration.

To avoid conflicts, I suggest the following steps:

1. First, make sure that the VLAN ID is unique within the UCS LAN environment. If the VLAN ID is the same in both VLAN groups, consider changing the VLAN ID in one of the groups.

2. When adding the new VLAN to the vNIC template, ensure that you're adding it to the correct template associated with the correct VLAN group.

3. Verify that the new VLAN is properly configured on the upstream switches and the correct port channels are trunking the new VLAN.

4. Double-check the pinning configuration on the vNIC template to ensure that the new VLAN is pinned to the correct port channel. If there's a conflict in pinning, you might experience issues in forwarding the traffic.

5. After completing the changes, test the connectivity to confirm that the new VLAN is functioning correctly and there are no issues in traffic forwarding.

By following these steps and ensuring that the VLANs are uniquely identified and configured correctly, you should be able to add the new VLAN to the vNIC template without causing any disruption in network traffic or confusion in pinning to the port channel.