Spanning tree on stack switches

[amin.amor]

I would like to know how the spanning tree will work on the figure below.

Which port will be placed in forward or block mode.

I think I must use spanning-tree stack-port in the second track that connect the two slaves.

If you have any experince with this topology, please let me know.

Regards

[cdfowlie]

In a topology like this, it's probably a good idea to set your masters as the STP primary and secondary root bridges. This will rule out any unpredictable behaviour.

i.e. on your primary

spanning-tree vlan 1-1005 root primary

and on your secondary

spanning-tree vlan 1-1005 root secondary

Once you have defined your topology, leaving nothing to chance, you can assume that the trunk between master-1 and master-2 will be forwarding, the stack links will be forwarding, and the trunk between the slaves will be blocking. I have seen some bad things happen if you don't select your STP root when scaling a network topology like this.

-HTH

Colin