Networking with Fibre 101

Can someone please sanity check this before I tear my hair out.

I've worked with fibre before but this new site is giving me an issue and I need to work out what points I've neglected to test before saying that i've goofed up.

Basically: -

I've got two cabinets in a new warehouse, connected by a fibre optic cable, 50/125 it is rated.

Both our Cisco switches have the standard GBIC WS5484 installed in them.

When the two switches are sat on the desk together, and connected with a fibre cable, this worked perfectly, then when they've been installed in their respective cabinets, I cannot get the two switches to talk to each other.

The fibre optic cable was installed by a 3rd party contractor, and they've tested it with their own equipment and it works fine.

The fibre optic is presented as SC at either end, and I've got SC-SC cables between the fibre outlets to the switches.

The SC-SC cables are marked A1 and B1 and A2 B2, which end goes where?

Is 50/125 incompatible with the WS-5484 GBIC - this is the only thing I can come up with at the moment.

I am pretty sure I asked for 62.5/125 before now..

Note, when I had the two switches together, I had 62.5/125 cable connecting them.

Now that I've seen it labelled on the cabinet that it should be 50/125 - i've got 50/125 SC-SC cables to go with.

What I'm scared now is someone is going to tell me that the WS-G5484 doesnt support 50/125....

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Comments

gorebrush

Ha!

Never mind, I have sorted it.

A bit of lateral thinking and I was away...

I looked at the set of 4 identical SC-SC cables that I had (redundancy - gotta have it!)

And figured that the way everything was connected up - the cables were sending data down the same hole... i.e. the receiving switch was getting it's light down it's respective SEND port, not receive.

Bit of magic with an SC cable later (i.e. pull the individual ends out of the plastic clip and swap them round) I have action!!

Awesome!!

Forsaken_GA

The WS-G5484's are rated for 50 and 62.5 micron, so that shouldn't be an issue.

You may have a bad jumper, or you might just have your RX/TX crossed. Plug em in, and if they don't link up, just switch the the connectors on one of your switches and it will probably come up. (and make sure you're not doing something dumb like mixing single mode and multi mode fiber! I know it's simple, but I've been guilty of it myself)

If that doesn't work, shoot the cables yourself, including the third party contractors.

Forsaken_GA

gorebrush wrote: »

Bit of magic with an SC cable later (i.e. pull the individual ends out of the plastic clip and swap them round) I have action!!

Yup, I don't have any of my fiber clipped into place just because I usually need to roll one end of the cable or the other if I guess wrong.

Glad you're good to go!

Chipsch

Yep was gonna say try rolling the cable, glad you got it fixed.

gorebrush

Looking at the first set of cables I bought though, it looks like the clip is made in such a way that you would have to break it off to get the individual strands out

Forsaken_GA

gorebrush wrote: »

Looking at the first set of cables I bought though, it looks like the clip is made in such a way that you would have to break it off to get the individual strands out

Yup, alot of jumpers are like that. Even the ones that have tabs for you to pry apart, you'll end up breaking when you try to take it off. I personally don't care, SC and LC cables are held in place by the design of the connector anyway, so I could care less if the clip is on there.