Layer 3 and vPC Interaction on Nexus 7010

[Adelaziz Ben Aziza]

Dear all,

I'm using to attach a layer 3 switch to vPC domain 1 (followin the network diagram). I buit a layer 3 Port Channel on my catalyst switch and i have to root the trafic to the next hope 192.168.0.1.

Is it necessary to use HSRP on the Nexus 7010, or is there another solution for attaching my switch to vpc domain 1? I see in some design document that vPC is not supporting layer 3 port-channel.

Thanks.

[Chad Peterson]

Hi Adelaziz,

Attaching a L3 switch to a vPC domain like this works when you point its next hop to the HSRP IP address on the Nexus 7000s.  When N7k runs HSRP either switch is able to route the traffic that use the HSRP address as their next hop.  This prevents the need of pushing the traffic over the vPC peer-link.

Running routing protocols and forming peer adjancies over vPC member links isn't supported.

Hope that helps clear it up

Chad

[Adelaziz Ben Aziza]

Hi Chad,

I can understand that there is no need of vPC when attaching this L3 switch to the 2 N7K, and it will be the same like i'm working with HSRP on 2 C6K (without VSS).

Abdelaziz

[Chad Peterson]

Well you really have 2 noteable options with your L3 switch that you are adding.  You could use a L3 link to each Nexus and avoid vPC all together, and use ECMP for load balancing.  This would usually be the recommended option.

If you do want to attach it via port-channel, you would want to use a vPC on the Nexus, with HSRP on that vlan.  The L3 switch would need to have a static route to the HSRP address and NOT participate with routing protocols with the Nexus switches.

[Adelaziz Ben Aziza]

Hi Chad,

I'm testing the second option since I want to attach my L3 Switch via port-channel with a static route to the HSRP VIP. I will also continue to use vPC on the 2 Nexus with HSRP on VLAN 1705.

Is it possible in this option to configure the Port Channel on the L3 Switch as a layer 3 port?

Thanks.

[Adelaziz Ben Aziza]

Option 2 is working now. Thanks.