Spanning tree putting interfaces in err disable

Heero

chmorin wrote: »

Any tutorials out there for putting in syslog? Does it cause any downtime in a production environment?

putting syslog in should not cause any issues, but I would always recommend you not make changes to a production environment unless you really know what you are doing. Might consider setting up syslog on a cisco router/switch and setting up a syslog server just to play a round a little bit and learn it. Its a very good thing to know.

Cyanic

I don't get all this spanning tree priority talk. If an election happens then a root bridge will be selected and ports will be put into blocking, but he is seeing ports going into error disabled mode and not a blocking state.

He is going to have to get the ports back into that mode and see what the reason is to fix this.

billscott92787

Cyanic wrote: »

I don't get all this spanning tree priority talk. If an election happens then a root bridge will be selected and ports will be put into blocking, but he is seeing ports going into error disabled mode and not a blocking state.

He is going to have to get the ports back into that mode and see what the reason is to fix this.

I agree because either way no matter which switch M0 or M1 is root, the Etherchannel should still work. Can you post the actual config directly from the other Switch? You are 100% sure that it is the exact same config? I just figured I could put another set of eyes on it and see if I see anything out of the ordinary.

Trifidw

The configuration is identical on both switches. The only thing that differs between them is spanning tree priority and HSRP standby.

Anyway, after lots of head scratching and reading I've come up with the following theory. We plugged in the second 10Gb link, spanning tree then decided to put the etherchannel into blocking mode at M0. Spanning tree then reconverged across the whole network causing an outage. Because communications across the etherchannel were being blocked by spanning tree, LACP messages were no longer being exchanged (and here's the weak part in my plan) M1 put the link in error disable because it thought it was a configuration issue?