Adding new Switch to network

It sounds like STP reconverged and a new root was selected - probably the new 3560. I suggest you look at the structure of your network (Layer-2 & Layer-3) and try and understand what happened as it's likely to happen again if you just plug switches in....

Andy

The new switch is likely configured as a vtp server with a newer stp revision, and it loaded its vtp and vlan config on all the other switches, wiping everything out.

Burt

I have never understood why Cisco insists on having their switches default to VTP server. If I was the manager of the switching division it would be set to vtp transparent from the factory.

ADB100 has it right..

What you could do on the new switch is set the priority really high for all vlans..


'spanning-tree vlan 1-4094 priority 61440'

If the VTP information was wiped out the network wouldn't have returned back to life after removing the switch..


BuckWeet

It did wipe it out---new information (the correct info) was put back in when the new switch was removed, from whatever the vtp server is.
Brian---totally agree!

Burt

By the way, the way to connect the switch is to set it as a vtp mode transparent or vtp mode client.

Burt

That's not the way VTP works.. The only way his vlan database would get overwritten is if the new switch has a higher version of database (which is unlikely and if he is using it hopefully he renamed the domain name)..

If it did have a newer version of database it would wipe out EVERY switch. The only way to recover is to rebuild it manually.

and FYI.. even in VTP client mode you can over write the vtp databases (if you have a higher database version, same domain name, etc..) VTP can be the devil if you don't understand how it functions..