Enterprise GPON / Zhone Questions

Wed Dec 12 12:35:21 UTC 2018

On Wed, Dec 12, 2018 at 10:16 AM Aled Morris <aled.w.morris at googlemail.com>
wrote:

> On Wed, 12 Dec 2018 at 06:48, Baldur Norddahl <baldur.norddahl at gmail.com>
> wrote:
> > It is possible one should not choose this system over a traditional
> approach, but the people screaming "rip it out" are out of line IMHO. It
> would be a huge expense to rewire a building with copper and they already
> got a working fiber system. Much can be said about GPON but it is actually
> quite stable and easy to manage.
>
> I don't think anyone is saying replace the existing fibre with copper,
> but instead to run cheap SFP-equipped switches in basically the same
> topology as the GPON you described.
>

That would still be costly in time and money with no obvious gain. You
would get some downsides however. Now you have many single point of
failures, a lot of small switches at the splitting points that need power
backup and be managed. And exactly the same issue with PoE that someone
raised. Only you will find more GPON ONT switches that already have the PoE
with a battery build in, because those devices where made to answer that.

Again not saying that you would make a new build in any particular way, but
to rip anything out of a brand new build requires justification. The
original poster might indeed have justifications, but the people
recommending to "rip it out" does not appear to have anything, but that
this is GPON technology. If your justification is that you only want to
work with technology known to you, then it is maybe you that needs to be
replaced.

It is certainly possible to build something close to the GPON system using
WDM instead. It is going to be more expensive. GPON splitters are very
cheap, WDM splitters less so and the DWDM SFP modules way more expensive
than the typical ONT. CWDM modules can be the same price as the ONT but you
need to add a switch to that. You will also have a problem with the multi
level tree approach.

> For a new build, less splitting and more copper in-building would be
> cheaper and easier.
>

Maybe. Those big fat copper runs get unwieldy and take up a lot of space.
That GPON system might have a 12 fiber, 3 mm cable as the backbone and a
maximum of 8 drop cables (2-3 mm) from the splitter. The drop cables are
much smaller than cat 6 cabling.

Regards,

Baldur
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