I see what you're thinking here, but I'm still not sure why adding a vlan to an existing trunk should ever cause a physical link to flap, or affect the underlying LACP session.
Harold 'Buz' Dale wrote: > Check the other end to make the the LACP config is correct and maybe a "sh > etherchannel" variation to look at what is going on. If the LACP is wrong > maybe the trunk was carried over gi1/0/1. > > Luck, > Buz > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Jared Gillis > Sent: Thursday, January 07, 2010 3:23 PM > To: [email protected] > Subject: [c-nsp] Adding vlan to port-channel trunk causes port-channel to flap > > Hi all, > > I just ran into a strange problem on a 3750ME. I've got two gig ports in an > active LACP port-channel looking like this: > > interface GigabitEthernet1/0/1 > switchport trunk encapsulation dot1q > switchport trunk allowed vlan 101,102,400,664,1000-2999 > switchport mode trunk > speed 1000 > duplex full > channel-group 1 mode active > end > > interface GigabitEthernet1/0/2 > switchport trunk encapsulation dot1q > switchport trunk allowed vlan 101,102,400,664,1000-2999 > switchport mode trunk > speed 1000 > duplex full > channel-group 1 mode active > end > > interface Port-channel1 > switchport trunk encapsulation dot1q > switchport trunk allowed vlan 101,102,400,664,1000-2999 > switchport mode trunk > end > > When I added vlan 400 to the trunk allowed vlan list, one of the underlying > gig ports flapped, which caused the port-channel to flap as well. > Jan 7 12:09:27.647 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface > GigabitEthernet1/0/1, changed state to down > Jan 7 12:09:27.656 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface > Port-channel1, changed state to down > Jan 7 12:09:28.654 PST: %LINK-3-UPDOWN: Interface Port-channel1, changed > state to down > Jan 7 12:09:31.464 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface > GigabitEthernet1/0/1, changed state to up > Jan 7 12:09:32.454 PST: %LINK-3-UPDOWN: Interface Port-channel1, changed > state to up > Jan 7 12:09:33.461 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface > Port-channel1, changed state to up > Jan 7 12:09:48.745 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface > Vlan400, changed state to up > > This definitely seems like something that should not happen. I'm running > Cisco IOS Software, C3750ME Software (C3750ME-I5K91-M), Version 12.2(46)SE, > RELEASE SOFTWARE (fc2). > Any thoughts on what I should be checking? > > --Jared > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
