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I have been having problems with a link flapping only when working with the AXM763 Module, but when I change 1G module it works without problems. Also there other 2 links with the same configuration working with the AXM763 10G.

I understand that the distance between my buildings is avobe the maximum distance, But How can I explain that 2 of those links work and only one fails.

I was reading cisco documentation and fiber specs and I found Mode Conditioning Patch cables are required for 10GBASE-LRM SFPs working on OM1 MMF because those cables reduce the effect called differential mode delay (DMD).

And I was thinking that this might help me with my problem, Can anybody help me with this problem? If it could work or not or if I missunderstood the Mode Conditioning Patch Cables.( I am not an expert in fiber)

Thank you!

10GBASE-LRM will only go so far over legacy multi-mode fiber. Officially, its reach is 220 m over 500 MHz·km fiber, 243 m could just about work when everything else is perfect.

A mode conditioning patch is worth a shot but I wouldn't bet on it - 10G-LRM is designed for MMF and should already launch accordingly. If you've got some 10G-LR transceivers at hand it's also worth a try with mode conditioning.

If everything fails and redeploying modern fiber is not an option you should look out for 10GBASE-LX4 transceivers - they're expensive but if you can get them they're pretty much guaranteed to work (offical reach is 300 m over legacy fiber).

Also, redeployment may be much cheaper when it's possible to pull preterminated fiber - you can get that very reasonably priced from many vendors. Use either OM4, OM5, or switch to OS2 altogether, especially when using budget transceivers.

Another (suboptimal) approach is to use aggregated gigabit links with or without WDM.

The point of a mode conditioning cable is to refocus the laser, this is traditionally used when using larger diameter multimode cable with single mode transceivers. basically the multimode cable has a lot more area for the light to disburse than a single mode cable.

For you application OM1 and 2 were never designed to handle 10Gig transfer rates over larger distances, the smaller diameter OM3 and 4 are really the types designed to push those 10Gig rates over longer distances. What the mode conditioning cable will do is to refocus the disbursed beam into something the receiving transceiver can read.

As for why 2 of the 3 are working. Well because you are just past the recommended limit any manufacturing deformities can cause the light to diffuse faster. At normal distances this wouldn't be an issue, but I suspect that because these runs are longer than the recommended 220m you are seeing some deformity in the glass.

But How can I explain that 2 of those links work and only one fails.

Because everything has variability, so when you are pushing the limits sometimes things work, sometimes they don't.

And I was thinking that this might help me with my problem

I would say it is certainly worth a try. A couple of mode conditioning patch cords are much cheaper than ripping out and replacing the fiber plant.

(p.s. in your diagram one of the mode conditioning patch cords is incorrectly shown, the singlemode fiber goes to the transmit port on the transciever while the multimode fiber goes to the infrastructure cabling)

I decided to try the Mode Conditioning Patch Fiber Cables, the link came up instantly, Its been around 2 weeks and the link works without errors.

Thank you.