nanog mailing list archives

Re: Outside plant - prewire customer demarc preference


From: Brandon Martin <lists.nanog () monmotha net>
Date: Fri, 24 Nov 2023 00:56:47 -0500

On 11/22/23 12:35, Sean Donelan wrote:

For *only* $1,000, the builder is willing to pre-install a smurf tube from the demarc to the central distribution point.  But such a deal for 5G....

Yeah that's ridiculous.  Running such a thing while the walls are still open is a piece of cake, and the material is maybe $50-100 depending on distance.

Since most fiber installs seem to use pre-connectorized cable, without affecting building structure integrity (i.e. 2-inch is too big according to builder), how small is too small?  Trade size 1/2-inch, 3/4-inch, 1-inch?

Does the FTTH industry have any published standards?

At least my experience has been that, where pre-connectorized drop cables are used, they're only pre-termed on the telco side (often, but by no means always in a hardened connector).  The customer side is either unterminated or uses a small ferrule with a snap-on housing precisely so that it can be fished through small holes in walls/framing and small or crowded conduits.

In practice, 1/2" trade size smurf tube is big enough if it's not too long and bendy especially if they're willing to get one with a pull-string already in it (and the guy before you is nice enough to pull another).  If it's a long or bendy drop or you want a little extra piece of mind, 3/4" is readily available not too expensive.  1" starts to get a bit expensive and is usually unnecessary.

I personally connectorize both sides in the field.  Having the ability to do it is invaluable for repairs, and it's not that much harder to do two sides than one especially if you're already fishing wires and such.  If you're using hardened connectors, the situation is different since they're not commonly available for field install, though it is a thing you can get.

I'm not aware of any published standards focusing on FTTx in North America.  All the standards I know of are datacenter/mid-size business oriented and are going to call for ridiculous (in FTTx) things like 2"+ rigid conduit on the assumption it'll have at least a 48F loose-tube in it and probably more than one.

I would imagine some of the national ogre telcos who are still doing FTTx deployments will have a pre-build guide for at least MDUs that might be useful, though around here they often just show up when the first person orders service and treat the building as "existing" even if it was just built last week.  I'm guessing they have so many existing buildings to deal with at least right now that this isn't a huge deal for them and may even be easier than having two classes of MDU installs (existing and pre-wire). AT&T and Centurylink/Lumen are the most likely to have them IMO, but checking Frontier/Verizon (do they still have ANY wireline territory?) may be useful, too, especially since they were the earliest ones to do it.

--
Brandon Martin


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