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GBIC WS-G5486 Connectivity issue

Dear All,

We have a problem with the GBIC WS-G5486 regarding its connectivity with the

fiber cables as explained below:

The problem simply is that the link distance is less than 1 Km, and the

Fiber Optic cable is single-mode, i'm installing the GBIC both ends in

7206-VXR with NPE-G1 router, the status of the interface in one side is

up/up and the other end is down/down...!!! when i disconnect the cable from

the down/down side, the other end becomes down/down, which means that there

is some kind of signaling reaches that end.

Any Idea can help us to resolve this problem??

Thanks in advance...

Best regards,,

Magdy Hossein


Re: GBIC WS-G5486 Connectivity issue

Hello Magdy,

You seem to have an unidirectional link condition. I know of two reasons for that:

1) one of the fibers of the pair is broken

2) one GBIC transmitter and/or receiver is broken

Regarding option 1):

Can you swap the fibers and see whether the interface down/down swaps sides? Replace the fiber in this case.

Regarding option 2):

In case the test above reveals no change in up/up and down/down, then you might have a GBIC problem. Either the receiver on the down/down side or the transmitter on the up/up side is broken. So replace a GBIC at a time until you get the link working.

Hope this helps! Please rate all posts.

Regards, Martin


Re: GBIC WS-G5486 Connectivity issue


Try this interface command on both routers:

'no negotiation auto'

If that doesnt help, then you either have a faulty GBIC on one end or a bad strand of fiber.


Re: GBIC WS-G5486 Connectivity issue


Insure that you have: 'media-type gbic'

VIP Purple

Re: GBIC WS-G5486 Connectivity issue


in addition to the other suggestions, there have been a couple of posts here lately describing exactly the same thing. I had an issue which is very similar to your while helping a client with new 3750 switches. How we eventually got it resolved was by unplugging the fiber cable, entering the command ´speed nonegotiate´, and plugging the cable back it. The interface came up after that...