Dual-active exclude

[jay_7301]

Hi All,

We use the dual-active exclude interface-vlan command. I understand this keeps up the SVI on the secondary switch if the VPC peer link fails.

We use the following technologies in our environment:

 - VPC

- Fabircpath

- VPC+

- OTV 

- VRRP between our 7k's

- VPC from FEX > Server

I'm wondering when will the dual-active exclude interface-vlan command will benefit us. As if the SVIs are shutdown then VRRP will failover to use the primary switch.

The only benefit i see is when orphan ports are connected to the secondary switch, however, if you connect them to the primary you shouldn't run into an issue.

Also if the VPC peer link is down and both SVIs are up will this not cause further issues?

Thanks

[Sergiu.Daniluk · Accepted solution]

Hi @jay_7301 

This commend helps you if you have orphan ports connected to vPC secondary peer device (or primary as at some point in time the primary, will become secondary). These orphan port connected devices will become isolated once peer-link is down.

The command will help you especially in a VXLAN (or FP in your case) + vPC implementation, when a vPC peer-link shuts down, but the uplink fabric ports are still up, all Layer 2 or Layer 3 orphan receivers behind the non-forwarder will not receive any traffic. Also, the local routing between orphan receivers from different vlans will not work.

The only 'problem' I see is that for the time vPC PL is down, the two SVIs will become both master. So you will see error logs with duplicate IP on the Nexus switches (if you have the L2 reachable between the vpc peers).

Stay safe,

Sergiu

[jay_7301]

Thank you for the swift response. Keep safe :)

[Jaime Valencia]

You are posting in the Unified Communications forum, probably want to move your thread to a relevant area of CSC.