Interfaces with HSRP & Spanning Tree

[j.lipsett]

I have 2 Cisco 4700 setup as follows - both have 1 serial & 4 ethernet 10baseT modules. On the ethernet LAN side both HSRP & spanning tree is configured.

The 4 ethernet port support 4 lans. with hubstacks resiliently linked back to both routers. Looking at the configuration of the routers one is the rootbridge and has all interfaces forwarding, the other router has one forwarding and all others blocking as expected. But with HSRP configured 2 interfaces on each router are active and the other on stanby. Does this not conflict with Spanning tree? I take it that the forwarding spanning tree ports only forward layer two frames, while the Active HSRP only forward layer three frames? or have I got this wrong?

[ivillegas · Accepted solution]

Actually the Spanning Tree and HSRP are different layer protocols and they will not conflict with each other. Are you bridging the trafiic , in that case Spanning tree can be used or else spanning tree is not necessary.