Catalyst 2950 hang on spanning tree loop error

[Patrick Pellegrino]

Hi,

I've a Catalyst 2950 with the latest IOS in. This switch it's connect by port 23 and 24 to two different switch (3750). Since yesterday, without any change, those 3750 detect a SPANNING TREE LOOP for the VLAN0001 (shutdown on all switch) on ports connect to the 2950.  When the error occur, the 2950 hang and I've to unplug the switch, wait and replug.

Does the 2950 can be defective and cause this ? Or it's a configuration error even I changed nothing ?

Thanks

Patrick

[Peter Paluch]

Patrick,

Is it possible to post the log messages that appeared on the 3750 (and perhaps on the 2950 if you have syslog records) around the time of the outage? This behavior is uncommon and it requires more specific information to at least begin with. The console or syslog messages recorded on the 3750 switches could provide us with important clues.

Best regards,

Peter

[Yogesh Ramdoss]

Peter,

You mentioned 3750 detected "spanning-tree loop". Can you post exact messages it has reported ?

- Yogesh

[amitak]

Hi,

Can you please paste the sh int (fas 0/23 -- interface connected to 3750) switchport command ?

Regards,

Amita

[Patrick Pellegrino]

It appear the switch is defective and problably the spanning tree error came when the switch hang and not the spanning tree causing the swich to hang.

We'll replace it and I'll close the post if nothing suspect appears.

Thanks to you guys.

Regards.

Patrick