Thanks for the fast reply.
The situation is as follows. I have now 2 5412zl cores,which need to be replaced by the R version.
I chose stacked distribution switches as to have one logical link to the new VSF core (to replace current distribution switches which are 2 in each building).
Currently we have just "spanning-tree" enabled on all switches (including access layer). Which ties in to my other post regarding what is the default spanning tree operation out of the box.
You are right that if i don't have full control over the rooms/cabling where the core switches reside, it's best to turn on spanning tree on the new Cores.
But on all of our other sites we are running MSTP with the idea of load balacing on L2 via 2 instances. This is our standard.
So first of all i would like to know:
- is there a documented statement somewhere which says "Always turn on STP on your VSF core in case **** happens" (or don't turn it on because it's not needed if you have only one logical link)
- if i don't have a need for load balancing, is there even a need for turning on MSTP explicitly, like the standard defines on my other sites? If the default is MSTP with instance 0, or RSTP, i have fast convergence anyways, so then i don't have to configure ALL my switches (including access layer) in instance 1 for example. I could just leave the spanning-tree command on all switches enabled which would have my entire network/VLANs in instance 0.
- Is there a HARD/Documented reason to have your VLANs placed in another instance than 0? Is there a danger so to speak?
For now my thinking is: Attach my new VSF core to the old Cores. Move SVIs from old to new with the "disable/enable layer3 vlan" command. And make the single VSF core have the command "spanning-tree" and "spanning-tree prio 0". Just leaving all of my VLANs in instance 0. Same on distribution layer.
I think it would be a bit redundant to map all my VLANs in instance 1 for example, if they are all located in instance 0 anyway and i don't need L2 loadbalancing.