Gbic problem

[Patrick McHenry]

I just installed a new switch in a new area on our main campus. I've cabled 2 uplinks for redundancy to both our cores. Yesterday, when I installed them, g0/1 went green and lit up. I couldn't get g0/2 to go green. Today, I pulled the fiber out of the gbic and as I put it partially in, the link went green but, when I put the fiber all the way into the gbic, the port would go dark. Right now I have it partially in and it is green and up but blocking as expected. Would this behavior(0f the fiber not being able to be plugged all the way in) point to a faulty gbic?

Thanks, Pat.

[zulqurnain]

Hi

Which switch is it ?

Would you be able to swap with two fiber cables and see the same problem with second GBIC in first port , if so then it would be surely Fiber cable and is not then it would be GBIC being lose or malfunctioning.

Sent from Cisco Technical Support iPad App

[Patrick McHenry]

Which switch is it ?

It is the access layer switch, 3560 PoE 24 port.

I'm going to try and swap the fibers now.

[Patrick McHenry]

It appears that it is not the gbic or the fiber as if I put the fiber that was failing into the gbic that is working, it comes up as well. And, if I put the fiber that was working in the gbic that was not working it also does not work.

But, there is more to the story that I didn't think had any relevance til now. The side that is working fine, is 50um all the way through to the core. The side that is not working properly, has one segment that is 62.5um. Could this be why the link comes up when I pull it out slightly?

Thanks, Pat.

[Reza Sharifi]

It could.  If you are using 62.5u then it needs to be all the way end-to-end the same type of fiber.

[Patrick McHenry]

ok Reza, thanks for the response. Actually it is all 50um except for one small piece that is 62.5. I will change that out next and to see what happens. I'm curious though, why it works when I pull it out slightly. Not only do I get a green link light but, it actually sends and receives traffic. As if pulling it out changes the size of the beam the correct amount to be compatible with the 62.5. I don't know but, in the mean time I am going to shut the port til I figure it out.

One last question: The gbics are LX. Can a signal from an LX gbic be carried by 62.5 if the whole path was 62.5?

Thanks, Pat.

[Reza Sharifi]

Pat,

Can you use SX instead?

GLC-SX-MM

Also can you provide the exact model number (3560 3560G, E, X)?

Reza

[Patrick McHenry]

The exact model is: WS-C3560-24PS-S

I could try SX but, I'm concerned of the distance. I'm not really sure of the exact distance either. I noticed that the switch in the downstairs closet in the same building was using LX so, I thought anything from the second floor closet should use LX since it is even a further distance from the core. Should I try SX?

Thanks, Pat.

[Reza Sharifi]

Yes, when your fiber is MM, you should use SX.

If your distance is 722ft or less, you should be fine with SX

have a look at table-2 in this link

http://www.cisco.com/en/US/docs/routers/7200/install_and_upgrade/gbic_sfp_modules_install/5067g.html

HTH