nanog mailing list archives

Re: High Density Multimode Runs BCP?


From: Scott McGrath <mcgrath () fas harvard edu>
Date: Wed, 26 Jan 2005 13:48:54 -0500 (EST)



Look into MPO cabling

MPO uses fiber ribbon cables the most common of which is 6x2
six strands by two layers

Panduit has several solutions which use cartridges so you get a
cartridge with your desired termination type and run the MPO cable between
the cartridges.

This cabling under another name is also used for IBM Mainframe channel
connections

                            Scott C. McGrath

On Tue, 25 Jan 2005, Deepak Jain wrote:



I have a situation where I want to run Nx24 pairs of GE across a
datacenter to several different customers. Runs are about 200meters max.

When running say 24-pairs of multi-mode across a datacenter, I have
considered a few solutions, but am not sure what is common/best practice.

a) Find/adapt a 24/48 thread inside-plant cable (either multimode, or
condition single mode) and connectorize the ends. Adv: Clean, Single,
high density cable runs, Dis: Not sure if such a beast exists in
multimode, and the whole cable has to be replaced/made redundant if one
fiber dies and you need a critical restore, may need a break out shelf.

b) Run 24 duplex MM cables of the proper lengths. Adv: Easy to trace,
color code, understand. Easy to replace/repair one cable should
something untoward occur. Can buy/stock pre-terminated cables of the
proper length for easy restore. Dis: Lots of cables, more riser space.

c) ??

----

So... is there an option C? Does a multimode beastie like A exist
commonly? Is it generally more cost effective to terminate your own MM
cables or buy them pre-terminated?

Assume that each of these pairs is going to be used for something like
1000B-SX full duplex, and that these are all aggregated trunk links so
you can't take a single pair of 1000B-SX and break it out to 24xGE at
the end points with a switch.

I priced up one of these runs at 100m, and I was seeing a list price in
the ballpark of $2500-$3000 plenum. So I figured it was worth asking if
there is a better way when we're talking about N times that number. :)

Thanks in advance, I'm sure I just haven't had enough caffeine today.

DJ




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