When using the LAG ports the switch only shows one of the ports as up.

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Jan 29th, 2009
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I'm seeing this on the integrated WLC within the WS-C3750G-24WS-S50, when attempting to use the LAG ports the switch only shows one of the ports as up. I have tried several things to troubleshoot on both the switch and the WLC but so far the other port has not become active.

Interface IP-Address OK? Method Status Protocol

Vlan10 X.X.X.X YES NVRAM up up

GigabitEthernet1/0/27 unassigned YES unset down down

GigabitEthernet1/0/28 unassigned YES unset up up

I have ensured the integrated WLC is set to enable LAG then rebooted the WLC and have configured & enabled the 2 logical Gig ports on the switch.

The software version on the Switch is 12.2.25 FZ and the software on the WLC is 4.2.61

The device is a WS-C3750G-24WS which uses logical ports Gi 1/0/27 and Gi 1/0/28 to communicate with the integrated controller

The 'several things' I tried was :-

1, On the Integrated Wireless controller, under the Controller-->Ports section there is the option to change the Speed from Auto to 1000Mbsp Full Duplex, The speed is already set to 1000Mbps on the second port (which is the working port), however when this was changed from Auto on the first port I lost all routing to the controller, and the controller had to be restarted to regain management.

2,On the Switch I changed removed the 'switchport nonegotiate' on both the Gig ports, this had no effect even after restarting both the Switch and WLC

3, On the Switch I removed the 'spanning-tree portfast trunk' on both Gig ports, again this had no effect even after a reboot.



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mark.cronin Thu, 01/29/2009 - 12:56
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what happens if you shut down the ports on the switch and physically disconnect 1/0/28

and then bring the ports back up

I expect 1/0/27 will be UP UP

Is this a spanning-tree issue?

ericgarnel Fri, 01/30/2009 - 12:13
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Check your global & local qos setttings. This is an issue with the wisms and certain flavors of IOS for the 6500s, perhaps it may affect the 3750 wireless units too.


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