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New Member

New fiber will not come up.



Sent from Cisco Technical Support iPad App:
Have installed a 24 strand (12 pair) OM3 (50 Micron) fiber run between two buildings. The distance is about 600ft. One end is a 4510RE Core Switch with a WC4306 GBIC line card, using a WC5486-LX/LH GBIC module. On the other end is a 3750G-24-PS switch with a GLC-SM-LH (think I have the correct) module. Using OM3 jumper cables.
Looking at the Cisco technical specs on all parts this should be good to go. However, no mater how we move the transmit/receive link, and what pairs we use, the link will not come up. Using our standard port/interface configuration of all Trunk links. This is the only GBIC>SFP on OM3 we have ever done.

Is there something in the configuration of the interfaces I need to do that I may not be doing?

1 ACCEPTED SOLUTION

Accepted Solutions
New Member

New fiber will not come up.

You are trying to run single mode optics on OM-3 ?

OM-3 is 50 micron multi-mode.

You can run LH on multimode but have to use a conditioning cable.

Even then the mode conditioning cable is not recommended on OM-3 or better fiber as it's for old 62.5 mmf IIRC

You didn't say what modal bandwidth your OM-3 is but even mediocre OM-3 should easily do 600ft with short range/sx optics. Of course there is more to your power budget than just what fiber you used but in general you should be able to run sx on that fiber.

4 REPLIES
Hall of Fame Super Gold

New fiber will not come up.

Ok, you'll have to do this the hard way ...

1.  Verify that the cable run is working fine.  Do you have a Visible Light or an OTDR to confirm the fibre is terminated correctly?

2.  Replace the SFP and GBIC three times; and

3.  Replace the SM fibre optic cables three times

New Member

New fiber will not come up.

You are trying to run single mode optics on OM-3 ?

OM-3 is 50 micron multi-mode.

You can run LH on multimode but have to use a conditioning cable.

Even then the mode conditioning cable is not recommended on OM-3 or better fiber as it's for old 62.5 mmf IIRC

You didn't say what modal bandwidth your OM-3 is but even mediocre OM-3 should easily do 600ft with short range/sx optics. Of course there is more to your power budget than just what fiber you used but in general you should be able to run sx on that fiber.

Re: New fiber will not come up.

Agree with Brian. Change out the optics for sx and I beg it works fine.

Sent from Cisco Technical Support iPad App

Hall of Fame Super Silver

Re: New fiber will not come up.

+1 on what Brian said.

The LX/LH type of GBICs and SFPs require single mode fiber end to end. OM3 is multimode.

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