3750 switch - need to connect using uplink

[ramonat]

i am trying to add a 3750 switch to the network. i want to config a fiber connection as the uplink to the core. i don't get any connectivity lights that its talking to anything. the fiber run is good because i can connect it to our old switch and all works. what am i missing? I've config the port the same as our old config uplink connection.

[b.julin]

Have you tried swapping receive and transmit strands? Are you trying to throw 850nm over a singlemode fiber? Is the SFP really all the way plugged in (some ofthem can be tricky.)? Are your patches good? Did you maybe forget to remove a shutdown statement?

That's where I would start.

[Yudong Wu · Accepted solution]

Check the following:

1. Make sure use the same type GBIC/SFP on both side.

2. Make sure the port is "no shut"

3. swap tx and rx of fiber

By the way, if it is SX, you should see a "red light" in one string of fiber pair and in TX side of SFP.

[mlund]

Hi

Sorry, this will be out of the original thread, but I think it is important.

If you are shure that the fiber You look into is connected to mm-fiber who is driven by a led, yes it will be red.

However what about looking into a fiber You are not 100 procent shure where it is connected.

It can be connected to a laser for long-reach connection.

I'm not sure if that is safe, I've been told that it can be a risk for your eyes.

Maybe someone out there knows for shure, if it is safe to look into a laser, or if you should avoid it.

If the recomendation is to avoid, I will suggest, never look into a fiber unless you are 100 procent shure where the other end is connected.

/Mikael

[ramonat]

yes checked all that and it is good. i'm going to swap out the sfp with a known good one and down grade the IOS to what the others are running. if that doesn't work not sure what else to check.