STP Priority

[daniel.bowen]

Hi All,

I have two core switches running numerous VLANs, and several access switches connected resiliently into both switches. These access layer switches run the same VLANs and I want to load balance them across both core switches. In other words, I want each core switch to be the root bridge for half of the total VLANs.

My question is, how do I configure STP to do this?

Can I simply adjust the switch priority on a per VLAN basis on the switch I want to have as the root bridge?

Many thanks in advance,

Dan

[ankbhasi]

Hi Dan,

You can run this command on your core 1

spanning-tree vlan root primary

and same command you can run on core 2 for same vlans to make it a secondary root bridge for those vlans

spanning-tree vlan root secondary

Use reverse for other set of vlans on 2nd switch to make second core as root and same command for those vlans on core 1 to make 1st core as secondary root bridge.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/configuration/guide/spantree.html#wp1037815

HTH

Ankur

*Pls rate all helpfull post

[krishnakomiti]

Hi,

Please check the below link, I think will be useful for you.

http://cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800ae96a.shtml

Thanks,

Krishna.

[Nagendra Kumar Nainar]

Hi,

If you have numerous VLANs, running PVST may result in increased CPU utilization. You can go for MST in that case.

http://www.cisco.com/warp/public/473/147.html

Regards,

Nagendra