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.
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.