3750 switch - need to connect using uplink

Answered Question

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.

Correct Answer by Yudong Wu about 8 years 1 month ago

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.

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b.julin Wed, 02/18/2009 - 08:31
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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.




Correct Answer
Yudong Wu Wed, 02/18/2009 - 08:35
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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 Thu, 02/19/2009 - 02:58
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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

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