Re: [Semi-OT] Public FiberOptic Network (Manufacturers)
On Wed, 01 Apr 2009, Marek Podmaka wrote:
> Tuesday, March 31, 2009, 18:11:18, Michelle Konzack wrote:
> > 1) FiberOptic cable
> > 2) End-User FiberOptic->Ethernet converter
> > 3) FiberOptic Switches?
> > 4) FiberOptic Routers
>
> > Any hints welcome...
>
> You probably should use passive fiber optic - this is what bigger
> providers you for FTTH. It's called GPON (ITU-T/G.984). For example
I have to agree: for large capilarity, GPON (or better yet, GEPON) is
a very good idea. It allows you to deliver reasonable bandwidth at
much smaller costs if you have hundreds of sites to connect (let alone
for thousands).
I do _not_ know if GPON and GEPON are going to cut it for the German
law requirements. The topology is highly assimetric re. upstream
versus downstream bandwidth, and the network design can have very
different levels of oversubscription, so check that first.
Whatever you do, you should have a real backbone of single-mode fiber
cable to connect the various POPs. And you should make sure you have
at least two paths to each POP, because you _will_ have fiber cuts,
often more than one at the same time.
Typically, one uses a mix of stars and rings for the backbone (if a
dual ring is not enough to cover all interesting POPs), where each
spoke or ring segment is done using two cables going through diverse
paths that never cross.
Also, laying the fiber cable is almost always a lot more expensive
than the cable itself inside a city (short hauls, lots of annoying
issues to lay the cable), so it pays off to not go cheap on the
backbone and get very good self-healing (if possible, armored) cables
with a decent number of fiber cores per cable.
You can do with a lot less fiber when using DWDM, but DWDM that you
can count on to keep your backbone working with a decent number of
nines is _very_ expensive. It is good for long hauls (like inter-city
ones), though.
The G*PON last-mile links are built the cheapest you can do and still
keep it running without too much downtime, though.
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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