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How do I get 3750 stack to run full backplane bandwidth

Hi, in the documentation it states;

"After adding or removing stack members, make sure that the switch stack is operating at full bandwidth (32 Gb/s). Press the Mode button on a stack member until the Stack mode LED is on. The last two port LEDs on all switches in the stack should be green. Depending on the switch model, the last two ports are either 10/100/1000 ports or small form-factor pluggable (SFP) module ports. If, on any of the switches, one or both of the last two port LEDs are not green, the stack is not operating at full bandwidth."

If I press the mode button on any one of the 6 stacks I've got, the duplex LED comes on and after about 2 secs the stat, duplex, speed & stack LEDS flash together. Nothing happens to the last 2 port LEDs. Does this mean that the stack isn't running at full bandwidth? This is the same accross all switches even after a reload.

Something else I've discovered which is quite alarming, is that if you hold the mode button down for approximately 10 seconds, the stack erases it's startup config and reloads, effectively defaulting the whole switch. I cannot find this documented anywhere, I suspect it's a bug as it's too much of a security hole to be a feature.

Has anyone else seen this documented anywhere?

Many Thanks in advance

Dom

1 REPLY
Blue

Re: How do I get 3750 stack to run full backplane bandwidth

There could be a couple of things to look at from the version of IOS on each of the 3750's in the stack to the way provisioning of a new 3750 into the stack was completed.

(ie: were switches in the stack powered on or off when added to the stack)

Please see the following link for Creation/Management of 3750 Stacks:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml

If you have IOS version mismatches, it would be a best practice to get them to the same version. You can use the steps in the following link to assist in upgrading the switches in the stack:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00804799d7.shtml

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