Spanning tree between 3 sites connected through L2 WAN

[hmc2500]

WE will have 3 sites connected at WAN Layer 2 (Metro Ethernet). What is the best way of configuring spanning tree on the L3 switches in these sites? Site A will be the new hub site. Site B branch and site C is the old Hub. All vlans will span all 3 sites.

Site A --------Site B----------Site C

I was thinking of making Site A (new hub) the root for all. Site B the secondary and give site 3 a lower priority. 

Input is appreciated.

[paul driver · Accepted solution]

Hello

If Site A traverses site B to reach Site C and vice versa, then I would say Site B would be best situated as the STP root.

[Reza Sharifi]

I was thinking of making Site A (new hub) the root for all. Site B the secondary and give site 3 a lower priority. 

That should work fine. Site-a 4096, Site-b 8192 and Site-c default.

HTH

[hmc2500]

Who's answer is best?. Would like to see a 3rd expert provide input or vote for the best answer.

[Reza Sharifi]

If Site A traverses site B to reach Site C and vice versa, then I would say Site B would be best situated as the STP root

I agree with Paul's comment above if the is your design, if not it doesn't really matter which side is the root.

HTH