vPC and VSS port-channel uplinks

[fuhrersk8]

Hello Forum Team!

   Currently I have a configuration of a couple of Nexus 5548UP in a vPC domain with a couple of Nexus 2248TP FEXs in a dual homed scenario for the access layer (FEX in  a vPC also). For Core/Distribution there is a pair of 6509 VSS cluster. Right now I configured a regular port-channel from each 5K to the VSS and is working as intended. My question is the following: since in vPC one 5K is primary and the other is secondary, can a vPC be configured for the uplinks to the VSS instead of a regular port-channel from each 5K?

Also, do configurations need to be replicated manually on both Nexus 5K? I am in denial for this. I am used for the way VSS works.

Thanks in advanced guys!

[Steve Fuller · Accepted solution]

Hi,

You can use a vPC from the Nexus 5K pair to the VSS cluster. There's a Cisco Catalyst 6500 VSS and Cisco Nexus 7000 vPC Interoperability and Best Practices white paper that goes into this. While the white paper is for Nexus 7000 presumably what you're interested in doing is the configuration shown in Figure 2 and so the scenario and considerations are the same.

On the Nexus switches with vPC there are still two control planes i.e., the primary and secondary as you mention. For any configuration that would need to be applied to both the primary and secondary, you have the option to manually configure on both switches or to use the Nexus Configuration Synchronization feature (see Configuration Synchronization Operations for more details).

It was 15-months ago we looked at the feature so things have likely changed, but following issues with our testing and issues we were seeing reported here in the forum at that time, we decided not to use the config-sync feature. Aside from any bugs, there are certain operational changes to consider, and so make sure you're comfortable with how config-sync works before putting it into a production environment.

Regards

[fuhrersk8]

 Hello Steve and thanks for your reply;

   I configured one port-channel on the VSS with the four up-links to the Nexus and one port-channel with same vPC ID on oth Nexus up-links to VSS as stated in the document but my management VLAN stopped responding (ICMP) on the Nexus. My scenario for the management on the Nexus is a SVI (not included in the vPC link trunk filter as stated in best practices document) so I am guessing that I will need to move the management to the Management VRF on the Nexus in order for this scenario to work.

Since the management VLAN ID is not included in the vPC link trunk filter, I guess I wont be able to extend this VLAN in a single vPC as in for FEX.

What do you think might be happening?

Thanks again for the information and support!