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3750 Gig port - no link light

I have a WS-C3750-48P, I cannot get the Gig port to link up to another switch with a copper cable. Fiber works fine.

I have tried a straight through and a Gig crossover, this is the current config.

interface GigabitEthernet2/0/1

switchport trunk encapsulation dot1q

switchport mode trunk

speed 1000

duplex full

no mdix auto


  • Other Network Infrastructure Subjects

Re: 3750 Gig port - no link light

I would try setting the speed as auto instead of hardcoding the speed and duplex . Also check the patch cables , all 4 pairs of wires must be good to connect at gigabit speeds .

Re: 3750 Gig port - no link light

If there is no green LED then you have a Layer1 problem. This might be f.e. a faulty port or a faulty cable.

Can you set two GigE ports to factory default and connect them with your cable? This should really give you a connection and would ensure that the cable and the ports are ok.

With the config given: are you sure the other switch supports GigE? I would give it a try with auto speed and auto duplex and auto mdix.

Hope this helps! Please rate all posts.

Regards, Martin