Enterprise GPON / Zhone Questions

Wed Dec 12 06:46:41 UTC 2018

On Wed, Dec 12, 2018 at 7:16 AM Ross Tajvar <ross at tajvar.io> wrote:

> I don't really have any advice to offer here (sorry), but I am curious how
> setting up a GPON LAN would save money vs just getting cheaper
> switches...and also what a GPON LAN even looks like. Does every office or
> classroom have an ONT?
>
>>
>>

Hi Ross

Every room will have a small switch style ONT. These devices can have a
small battery for power outages and provide PoE to voice over IP phones.
Typically the ONT switch has from 4 to 24 copper ethernet ports.

The building will have a tree like structure of splitters. For example if
there are four floors, you might have a 1:4 splitter at the entrance to the
building, then on each floor you could have another 1:4 splitter to four
sections and then in each section you might have a 1:8 splitter to provide
network to 8 rooms. Of course this could be designed in many different
configurations depending on the needs and layout of the building. The
maximum combined splits is 128. In my example we had 4*4*8 = 128 splits. If
you need more, you will deploy additional OLT ports with new splitter trees.

As to cheaper I can not say. I am not selling any of this stuff. I can say
that the price for a small 4 port ONT switch is about USD 50 to 100. The
battery is extra but not very expensive. It is just a small cell phone
style battery that plugs directly into the ONT, not a full UPS system.

It is possible to build this with redundancy. I suspect it is rarely done.
The redundancy works in the way, that the 1:8 splitter can be replaced with
a 2:8 splitter. This has the same power budget, but you get two input ports
to the splitter. Only one can be active at a time. The GPON OLT switch
needs to coordinate which of the input ports is used. How that is done is
vendor specific. You would build an independent backbone tree for the
second input port to the splitter.

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.

Compared to the traditional approach, you will only have one centralized
GPON switch to manage. All the small ONT switches are managed through this.
Complaints about the interface is vendor specific. Because there is only
one centralized switch, it would be fairly cheap to switch vendor. Much
cheaper than to rewire with copper in any case.

Regards,

Baldur
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20181212/86bd3b5a/attachment.html>