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Spanning-tree and Catalyst 4507R

One network with one Catalyst 4507R as a spanning-tree root ID (priority 4097)

one Catalyst 2950 as a backup, and 18 catalyst 2950 distributed in different plants from the building.

The 18 catalyst connect to 4507R with 1Gb link, and with 100Mb link to 2950 backup.

Without apparent reason, a loop of spanning-tree is created and the

network performance goes down.

I have reviewed the wiring, configurations and bug of IOS.

Somebody knows as it can be the cause of this problem.

1 REPLY
Bronze

Re: Spanning-tree and Catalyst 4507R

start by checking the 4507R logs for mac address or host flapping messages. It should have reported that certain mac addresses were been seen on ports that you know, in a stable situation, should not be learning those mac addresses.

Do all the mac addresses that were flapping between links all belong to one vlan ? If so, then you know the issue occurred on one vlan and not on multiple vlans. If the mac addresses belong to multiple vlans, most most likely there was a trunk link that was getting all flaky..perhaps a gbic or something.

Check out the "troubleshooting spanning tree problems" doc on Cisco.com for more troubleshooting tips

URL: http://www.cisco.com/warp/customer/473/16.html

AND

http://www.cisco.com/warp/customer/473/62.shtml#t36

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