strange spanning-tree vlan output

Unanswered Question
Feb 1st, 2008

Hi All

I have a problem with my cisco3750 switch..

If I issue sh spanning-tree summary I get

(look attach)

In particular for vlan 242 and 243

VLAN0242 - 245 - 249 - 253 -1872756559 1012957184

VLAN0243 - 245 - 249 - 253 -1872756559 1012957184

if I issue sh spanning-tree vlan 242 or 243 it gives

sw-com1-be#sh spanning-tree vlan 242

VLAN0242

Spanning tree enabled protocol ieee

Root ID Priority 4338

Address 0005.dd27.3440

Cost 4

Port 1000 (StackPort1)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 45298 (priority 45056 sys-id-ext 242)

Address 0019.3027.f580

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa1/0/9 Desg FWD 19 128.11 P2p

As you see no root port in the output... but the infrastructure works well machine in the same vlan (242 or 243) cona communicate...

What happens ???

Regards

Giuseppe

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Edison Ortiz Fri, 02/01/2008 - 08:25

Please attach the whole show spanning-tree output, not just the summary.

__

Edison.

tricaricog@tin.it Fri, 02/01/2008 - 08:47

I added the show spanning-tree output and sh spanning-tree root port command

Note: switch is stackwise with other 2 switch..

Vlan 242 and 243 are the only that have the stack port as root port...

Is it normal ??

T

Edison Ortiz Fri, 02/01/2008 - 09:19

I never seen the stackport listed in the spanning-tree information.

Are you having multiple 3750 switches connected using the stackwise cable and you also used the front switchports for inter-switch connection?

Can you post the output from typing show switch and show cdp neighbor detail

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