Wednesday, February 13, 2019

Seeking advice on MDU deployment...

My team was recently brought in to take over where a previous contractor failed to meet timelines along with overall failure of the projects. One of the terms of the contract they signed was to build networks (7 of them were "completed") which provided 10Gbps backhaul from an MDU to anywhere from 2 to 30 IDFs, whether these be in a high-rise building or structured more like an apartment complex. The consistent issue across the board is that OM1 MMF was originally deployed between the MDF and each IDF.

Where the complexity comes in is the MDF core switch is a Brocade ICX7750, which while it is a powerful switch and full-featured, it requires special 10GBASE-LRM optics in addition to only accommodating 12 10GB-LRM in a single chassis. We didn't know this when we got involved to take over the contract, and are looking for a way to continue deploying at each of these sites where OM1 fiber is in place, at distances of 900+ feet, and where 10GB is a requirement.

With that being said, we have considered mode-conditioning fiber cables so that we can use 10GB-LR modules on MMF which may help some, but it's still not ideal. I am completely unconvinced that 10GB-SR would be feasible to operate on this since all of the links are >30 meters.

So, aside from the idea of stacking media converters or going to the client and asking them to replace a 48 port 10GB/6 port 40GB switch with something that's more accommodating for this build, what would you guys do? I've considered going as far as placing a stack of Routerboard CRS317 units with 2 DACs for the uplinks to the 7750 and then 10GB-LRM off those to each IDF which would be fairly reliable and expensive to deploy, but I am trying to avoid any additional equipment in these sites since so many of the racks are near capacity.



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