DWDM on 250 Km dark fiber without re-amplification

Robert Jacobs rjacobs at pslightwave.com
Tue Dec 27 23:20:46 UTC 2016

Polarization and dispersion will come into play at these distances if you plan on running a DWDM system.  In that world you get what you pay for as a rule.  The more expensive gear is more forgiving to fiber that is not 100 % up to high quality.  Most small one or two RU gear from all the vendors mentioned have 100 gig cards that will be 100 gig on the DWDM side and break it out to 10 sfp Plus ten gig ports for the client side.  Another thing to look for in this is link down propergation ... you will want the client facing links on both sides of the optical span to go down if the span goes down.  Good luck with your quest 

-----Original Message-----
From: NANOG [mailto:nanog-bounces at nanog.org] On Behalf Of Eric Kuhnke
Sent: Tuesday, December 27, 2016 1:18 PM
To: Jeremy <liste at freeheberg.com>; nanog at nanog.org list <nanog at nanog.org>
Subject: Re: DWDM on 250 Km dark fiber without re-amplification

You will want to request an OTDR characterization of the dark fiber path from its owner. If you can post OTDR "shots" with full resolution images in a lossless image format to the list, we may be able to take a guess if the distance is feasible without amplification inline.

For equipment choices you're looking at the usual vendors for DWDM long haul ROADM chassis such as Ciena, Adva, Huawei, ZTE, Infinera, etc.

If you simply want to do point to point DWDM mux:demux on the 250km fiber, your choices will be different than if you want the ability to insert a chassis at an intermediate location and drop or insert wavelengths.

It may be possible, at a lower cost than buying 100GbE capable DWDM chassis type systems, to do a single router-to-router linecard link with coherent 100GbE signal with FEC on the 250km path. Again this will totally depend on the OTDR results and link budget available.

On Fri, Dec 23, 2016 at 4:14 PM, Jeremy <liste at freeheberg.com> wrote:

> Hi all,
> First, i'm sorry for my english, i'm french and i don't have a good 
> level in this language. But i want some informations and i'm sure, 
> someone will be give the good anwser about my question.
> So, i'm regarding to rent a dual dark fiber in France, the estimated 
> distance is 225 Km, but i know there are a lot of optical switching on 
> the highway where it's fiber is installed (in theory, all 80 Km). So, 
> i used the bad scenario, in adding 25 Km on my need.
> I would like to buy a amplificator and multiplexer DWDM to add some 
> 10Gb/s waves on this dark fiber. I've see that the amplification is 
> better on 100 Gb/s synchronised ports, but we don't have enoug 
> capacity on our router to add 100 Gb/s interfaces.
> So, someone has installed this type of hardware on a dark fiber 
> without regeneration  on 250 Km of distance ?
> If yes, with what kind of hardware ? If you are commercial for this 
> hardware, please contact me in private message.
> Thanks you for your time,
> Jérémy
> AS197922

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