Enterprise GPON / Zhone Questions

Wed Dec 12 22:32:22 UTC 2018

On Wed, Dec 12, 2018 at 10:52 PM William Herrin <bill at herrin.us> wrote:

> YOUR use of PON makes reasonably good sense.
>
>
Features such as battery backup and ISDN is made for the explicit purpose
of office buildings, not residential use. The flexibility that we enjoy
will also work for office buildings. I do not disagree that in a office
building the distances are short and you can get enough flexibility just by
adding sufficient amount of dark fiber, and therefore a point to point
network would work just as well. But what he got is a GPON network, so what
else would also work is moot. Nobody has yet to come forth with a real
problem with the GPON network, that would require to start all over with
another approach.

>
> > One advantage of a fiber to the desktop solution is that you have
> >fiber to every room. You just move a drop cable from the splitter
> >and to a pair of backbone fibers.
>
> Did it read to you like Nick's installation had drop cables of
> non-trivial length from easily accessed splitters? It didn't read that
> way to me.
>

The length of the drop cables is irrelevant. You are not going to move the
cables physically. You will unplug the drop cable from the splitter and
connect it to the backbone cable. Both splitter and backbone cables will
have APC/LC connectors in a small cabinet somewhere. You can literally
convert a drop cable from being part of the GPON system, to being a point
to point anywhere within a few minutes just by moving a few connectors.

>
>
> >> I would demand the creation of comms closets and risers before the
> >> building opened and I'd threaten to quit if they weren't. At least
> >> then the inevitable modifications can be structured and planned
> >> instead of turning in to an ad-hoc mess.
> >
> > This is out of line IMHO. Hopefully they did add in extra conduits so
> > you could do some special cable runs (including some copper and
> > coax), if needed.
>
> Nick said they did not create comms closets or a comms riser.
>

He did not say there was zero space to run any cables at all. Fiber does
need very little space. And if all you need is that coax for the AV group,
that also would not need much space. If you wanted to rewire the whole
thing for copper, that would require a lot of space. Rewiring for point to
point fiber would require very little space, if any at all (we do not know
how much dark fiber they already have).

> If they did the fiber build in anything reasonably close to the
> recommended way there would be ducts connected to comms closets
> holding the splitters. He's already told us there are no comms
> closets.
>
>
No in a fiber build you would not bother with comms closets. For copper you
need to ensure no run is longer than 100 meters, and therefore you have
risers and comm closets relatively close spaced. In a fiber roll out there
is no point. Even with point to point ethernet over fiber, you would just
have one closet for the whole building in the basement somewhere. Or even
in a different building. The architect is going to want that space for
something else in a heartbeat. This more than the saved cost could be the
real reason for why they did it.

This does not mean there will be zero space for running cables. You still
have lots of stuff that needs to cross floors (power, water, sewer, fiber
etc).

Regards,

Baldur
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