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New Member

SFP to GBIC Issue

Hi. I was trying to uplink a switch today on a 1500m run of SMF.

I have a 6509 core switch with a 16 port GBIC module. On that end I have a WS-G5486-LX with a 3m SC to LC patch cable.

On the other end I have a 3750G with a GLC-LH-SM SFP. I have checked my fiber path and it seems good, (by sight, did not have an OTDR avialable).

I can't get the link up at all. Tried swapping Tx Rx at one end, Tried different transceivers. Tried different patch cables. Nothing worked. At about the mid-point of my fiber run the cable passes through another network closet with a core switch for a separate network. If I break my fiber path there and try to connect in either direction it works. The only differences are the length of the fiber run and that the core switch on the other network has a CLC-LX-SM SFP.

Is it the distance? Or is there some issue connecting a GLC-LH-SM to a WS-G5486-LX?

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7 REPLIES
Hall of Fame Super Gold

SFP to GBIC Issue

I have checked my fiber path and it seems good, (by sight,

Doing this is dangerous as it will cause permanent eye damage.

Get a light-stick if you don't have an OTDR handy.

Are you sure your backbone is SMF?

New Member

SFP to GBIC Issue

Yes it is single-mode.

And I used a lightsorce to check the fiber. You can't really see the light generated by smf transceivers. If it was mmf you would be able to use a black cloth to see the ambient red light in the transceiver or the tx lead of a patch cord plugged in to a transceiver.

Hall of Fame Super Gold

Re: SFP to GBIC Issue

And I used a lightsorce to check the fiber. You can't really see the light generated by smf transceivers. If it was mmf you would be able to use a black cloth to see the ambient red light in the transceiver or the tx lead of a patch cord plugged in to a transceiver.

Yes but the laser for the SM is STRONGER than the MM.

At about the mid-point of my fiber run the cable passes through another network closet with a core switch for a separate network. If I break my fiber path there and try to connect in either direction it works.

Hmmm ... Looks like it's not compatible.  Look at Table 6 of this document:  GBIC Module and SFP Module Cabling and Connection Equipment

According to this document, you may need "ZX".

Re: SFP to GBIC Issue

can i have the exact model and sup model of the 6509 switch.... so that i can check the compatible gbic model for the same.....

Because i guess WS-G5486-LX is ideal gbic model for 3500 & 2900 GBIC model switches not folr 6509.....

Also even though if u r able to see light also there might be a possibility of a cabling path issue....either tx or rx link wud have the problem....

Re: SFP to GBIC Issue

WS-X6416-GBIC

GBIC

16 ports; 1000BASE-SX, -LX/LH, -ZX, -T; 1000BASE-CWDM, -DWDM; SC connecter

I guess the above GBIC is the ideal model for 6509-16 Ports.... Hope this would be the problem..... Please check by changing that.... hope this helps....

please rate if the info helps

New Member

Re: SFP to GBIC Issue

WS-X6516-GBIC is the GBIC blade in my 6506.

A little more info on the fiber:

62.5 micron single-mode fiber, 8000 ft run.

The specs sheet for WS-G5486 and GLC-LH-SM both show them only capable of 1800 ft over that size fiber. However, I got them to link up at 6000 ft with no issues. But I need it to link at 8000 ft!

Re: SFP to GBIC Issue

Nope... GLC-LH-SMF range covers up to 32,000 feet..... only the GLC-LH-MMF covers max of 1800.... distance should not be the problem.....

I suspect there should be someother problem..... 

is there any other OFC connectivity between those locations already running using single mode ????

Because if it is a single mode... then end to end we should have the SM as the backbone..... else this will not work if we have partly MM fiber backbone connection.....

Building A to Building B

<---------8000ft------------->

for eg if you are connecting the link between building a to b .... say building a scond floor to building a ground floor to building b ground floor to building b 2nd floor.... in the above case we should have the SMF backbone for connecting 2f to ground floor as well on each buildings..... 

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