XGS-PON can theoretically run at 100km, though 60km is about the practical limit we have seen, With a active cabinet in the center and a 60km reach you can have an effective diameter of ~70 miles. With slack, routing, sag, etc. 50 miles is a possibility for cabinet spacing.
In the rural areas we use a 10 mile radius with active cabinets 20 miles apart. The active cabinet feeds unpowered splitters either in splice cases along the way, and also feeds passive splitter cabinets in the pockets of density (subdivisions, villages, towns). If the density in a village becomes high enough (or grows) the passive cabinet can be changed to an active cabinet and the fiber previously used to feed splitters becomes your 100G feed into the cabinet. The cabinets that are 20 miles apart have a ring (well, more of a mesh) feed of 100G links to them to provide redundancy, but there is no protection for the PON customers on the passive side. There are ways to provide for PON redundancy including dual fed PON’s with a live / standby link, but it’s significantly more complex to engineer (and IMHO not worth the complexity) given the overall reliability and simplicity of GPON. For a high value customer that needs redundancy active fiber is simpler to deal with for creating redundancy. Mark > On Mar 15, 2024, at 7:57 PM, Ken Hohhof <khoh...@kwom.com> wrote: > > Since there are FTTH people here and I’m mostly ignorant of such things, > maybe someone can clear something up for me. > > I always assumed a PON based FTTH system had a topology kind of like HFC. I > expected fiber down the street with splitters, but fed by some sort of > neighborhood node in a cabinet with power and electronics, fed by active EPL > style fiber. Which could have redundant paths, rings, etc. so a fiber cut > wouldn’t take down a whole town or multiple towns, the backbone traffic would > reroute. > > I’ve been told this is not the case. And that instead, each PON could go > back over a strand to a headend several towns and many miles away, all > passive. > > Sorry for the poor description of my question, hopefully you can figure out > what I’m asking. > -- > AF mailing list > AF@af.afmug.com <mailto:AF@af.afmug.com> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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