Switch / VLAN Trunks and STP

[makkers]

If I have 3 Cat 3548 Switches interlinked with bkup link i.e. in a triangle formation , STP will block one of these ports to prevent loop.

1. If I make these 3 interlinks all trunk links so that my VLAN's are avail on all 3 switches will spanning tree still do its stuff?? or will spanning tree throw a wobbly.

2. Do I need to consider pvst or can I allow this to dynamically settle?

3. My network diameter is 5 and user count is approx 50 on any one vlan.

Any views and experiences appreciated

[t.baranski]

You should be fine with either standard spanning tree or PVST. I don't think PVST will give you any advantages unless you want to do some load sharing between the uplinks.

[vincent-n]

I would strongly recomend you to assign root bridge and backup root bridge in your network. I normally pick the most powerful switch and in your case they're all equal then I'll pick the one that has my Enterprise Servers mainly connected to.

Vincent

[mdoldan · Accepted solution]

I prefer MST in this configuration due to the faster convergence time. I also recommend a root and backup for spanning tree. Be sure your root is a VTP server. When dealing with MST I'd also recommend setting the root of the spanning tree a higher MST revision number than the others. the secondary root should have the second highest revision number and so on. If you are running Fastetherchannel make sure you do not use the switchport mode access on any port bundles. Use the switchport trunk native vlan command and switchport mode trunk.