Trunk uplinks problem

[j.mccartney]

Hi,

I have a strange problem on two links in my network that I can't figure out. I have problems with one 6509 1000BaseSX module that has two ports connecting to two other 6509's as redundant links. Every so often they will drop out of STP with "%PAGP-5-PORTFROMSTP:" error and soon after will come back. I first reseated the links and then replaced the patch cables but the problem keeps occurring every so often. They seem to run OK for about a week after I replaced the patches/reseted. Suspect the module might have something going on. Any ideas? Thanks.

Versions are 5.4(2)FW and 5.5(12)Sw

[thisisshanky]

Do you have etherchannel configured on these two links ?

Give a "show port capabilities" on either ends to see whether all parameters on both links have been set properly.

Can you also paste the rest of the error message that pops up. (that means, the message that comes after "%PAGP-5-PORTFROMSTP).

[j.mccartney]

We do not have EtherChannel config'd on these, below is output taken from one of the links with the alarms listed from today.

SW12 3/3 connnects to SW13 2/1

SW12

======================================

sw12> (enable) show port capabilities 3/3

Model WS-X6416-GE-MT

Port 3/3

Type 1000BaseSX

Speed 1000

Duplex full

Trunk encap type 802.1Q,ISL

Trunk mode on,off,desirable,auto,nonegotiate

Channel yes

Broadcast suppression percentage(0-100)

Flow control receive-(off,on,desired),send-(off,on,desired)

Security yes

Membership static,dynamic

Fast start yes

QOS scheduling rx-(1p1q4t),tx-(1p2q2t)

CoS rewrite yes

ToS rewrite DSCP

UDLD yes

Inline power no

AuxiliaryVlan no

SPAN source,destination

COPS port group not supported

003 Nov 10 06:49:57pst -08:00 %PAGP-5-PORTFROMSTP:Port 3/3 left bridge port 3/3

2003 Nov 10 06:49:58pst -08:00 %DTP-5-NONTRUNKPORTON:Port 3/3 has become non-trunk

2003 Nov 10 06:54:15pst -08:00 %DTP-5-TRUNKPORTON:Port 3/3 has become isl trunk

2003 Nov 10 06:54:17pst -08:00 %PAGP-5-PORTTOSTP:Port 3/3 joined bridge port 3/3

SW13

====================================

sw13> (enable) sh port capabilit 2/1

Model WS-X6K-SUP1A-2GE

Port 2/1

Type 1000BaseSX

Speed 1000

Duplex full

Trunk encap type 802.1Q,ISL

Trunk mode on,off,desirable,auto,nonegotiate

Channel yes

Broadcast suppression percentage(0-100)

Flow control receive-(off,on,desired),send-(off,on,desired)

Security yes

Membership static,dynamic

Fast start yes

QOS scheduling rx-(1p1q4t),tx-(1p2q2t)

CoS rewrite yes

ToS rewrite DSCP

UDLD yes

Inline power no

AuxiliaryVlan no

SPAN source,destination

COPS port group not supported

2003 Nov 10 06:49:53pst -08:00 %PAGP-5-PORTFROMSTP:Port 2/1 left bridge port 2/1

2003 Nov 10 06:49:53pst -08:00 %DTP-5-NONTRUNKPORTON:Port 2/1 has become non-trunk

[thisisshanky]

Since there is no etherchannel configured, STP will run between the switches on both links and one of them will be in forwarding state and the other in blocking state. The above error messages could be due to a link flap. How often are you getting this messages ?

[j.mccartney]

It varies, sometimes it happens a couple of times a day and other times it goes without an error msg for a week. That is why its kind of hard to pinpoint it. I appreciate your help.