08-22-2007 05:28 PM - edited 03-03-2019 06:26 PM
Hi all,
If three switch connected as seris like a circle, then STP will elect the root bridge within three switch.
How about if two switch connected with a single link, Will STP occur and will Root bridge will be elected ?
08-22-2007 05:32 PM
No, not with two switches and just one link.
STP breaks topology loops. With only two switches you need two or more links connected between the pair.
08-22-2007 05:32 PM
Jack
If two switches are connected with a single link then Spanning Tree will run, BPDUs will be sent over the link, and a Root Bridge will be elected. In this case no ports will go into blocking mode (if the switches are connected with a single link there is no possibility of a loop so no blocking).
[edit] with all due respect to Joseph, whose response got in just barely before mine, even with 2 switches STP will run. Your answer emphasizes that there can be no loop and therefore no blocking. But that does not mean that STP does not run.
HTH
Rick
08-22-2007 06:26 PM
Richard is 100% correct, spanning tree, if enabled, will run. (And often a good idea to enable to avoid "accidents" when someone mis-patches or someone brings in a "personal" switch even for topologies that don't have intended multiple paths for redundancy.)
You're also correct, what I had in mind was STP wouldn't have any loop to break in a 2 switch one link connection unlike the 3 switch loop described as part of the original question.
Again, Richard, thanks for the correction.
08-22-2007 05:34 PM
> How about if two switch connected with a single link, Will STP occur and will Root bridge will be elected ?
Yes.
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