spanning tree actions

[carl_townshend]

Hi all

can anyone tell me about tcn's, if i was to add another switch to my network what would happen, it would not cause the network to reconverge would it ?providing I have the root bridge priority set of course, would adding the switch send out a tcn to everywhere, and what info would it have on it ?

[bvsnarayana03]

When a new switch comes up, it sends BPDU's with its own BID as root ID. When the neighbor receives this BPDU, it matches the BID with current root. If the existing root BID is superior, it'll update the new switch by sending this info in the BPDU & the new switch updates its info.

However, if the new switch has a superior BID than existing root then TCN will be flooded to update the network topology.