Make sure that the fiber from one end is crossed to the other end. For example, switchA <--< SwitchB, switch A>-->SwitchB. I am trying to show the rx and tx of the connectors, if one side is rx it shoud tx on the other side. Other than the LED, what is the status of the interface? down/down, up/down?

Try setting the speed option to auto (assuming that it was statically set before). Also, make sure you did not use the nonegotiate command on the actual switchport.

Are these brand new gbics or are they used?

Did you shine light down your fiber patch cable to make sure there are not breaks or severe microbends in it? Hope this helps.

Hi there,

If you type the command "sh interface status" it will tell you if it can see the Gbic and what type it is. As there is no light, that would point towards a layer 1 error.

You need to ensure that:-

1. The switches can see the gbics.

2. They are both 1000mb ports (I've had problems in the past trying to connect 100mb ports to 1000mb ports)

3. The fibre is clean and not broken

4. You connect transmit to recieve on the fibres.

Please rate helpful posts,

Hope this helps a bit,

LH

CCIE#15331