3750G fiber run not working to other 3750G switch

[blade10]

All-
I have this issue and need fast solution.

I have a 3750G on one side of a company building and another about 150 feet away..

The fiber from both sides was connected to older 3548 switches and now I've upgraded to 3750's.. long story short, when I plugged the fiber mods and cables into the new 3750's it looked like the fiber light on port 25 lit up and stayed up.. (these are 28 port switches by the way, the last 4 ports are fiber mod ports)

Now, there is no light on each side for fiber at all! Question: do I need to configure these ports or should I assume if the fiber is working from end to end that it should just light up... do I need to setup portchannels???

just need to know if should digging into Cisco url white papers or anything else??

thru deperation I plugged the fiber ends into the old original 3548s and i still have no lights at either end! I assume these fiber runs are more than 4 yrs old and we just broke the fiber end from either side so now we have no access at all..

can someone provide some guidance.. keep in mind, I've purchased all proper connectors to make this fiber work (couplers, fiber patch cable etc with an engineer all is good on all the connection issues to make the fiber retrofit the newer 3750 switch)

thanks and I really need help here

blade10

 

[jneiberger]

If you connected this fiber to the old switches and still have no link light, my guess is that you broke a fiber strand at one of the connectors during the move. Have a cabling expert examine, clean and possibly re-terminate the fiber.

 

[blade10]

thx j-

Thats what I thought, just wondering if I need to specifcally configure ports 25 on each end (there are 4 fiber ports) on this 28 port switch by the way) as fas as fiber configurations go. Should I trunk the? via 802.1q? or should I assume it would just work.

eitherway, plugging it back to the old switches shows that there is no activity, just dead.......

thanks, any additional input on this would be awesome, I have a vendor coming shortly on this issue to test...

thanks again!~
blade

 

[jneiberger]

If you're not getting link light with the old equipment, that really makes me think something is wrong with the fiber. As far as configuring the new switches, just leave them at the default configuration and the trunk links should come up automatically. Make sure you have the same VTP settings on each side. The rest is automatic.

 

[blade10]

Jneilberger-

It turned out the fiber run was multimode yet we ordered the wrong cable (single mode fiber) so we worked that out.. BUT, now I still have the same problem...

the fiber is not working from switch to switch.. ports 25-28 are fiber ports.. no activity at all.

Maybe I am not configuring this correctly here.. What do I need to group these fiber ports in at the switch -port channel? etherchannel mode? perhaps a vlan?

here is what I have:

switch 1
vlan1 all port 1-28 are in this default vlan..
|
| <---multimode fiber between switches
|
switch 2
vlan 1 all ports 1-28 are in this default vlan...

there is no trunking or specific vlans setup... what do I need in the config to see end to end connectivity.

thanks for any info you, the cisco white papers just states to slap the gig mod in the slot and plug in fiber (for both switches) but this is probably not so....

again any info in this would be great!

blade10