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Re: Advice/Experience with small sized DDWM gear
From: fkittred () gwi net
Date: Thu, 07 Aug 2003 16:26:10 -0400

On Fri, 20 Jun 2003 14:56:41 -0400  "Deepak Jain" wrote:

We are looking for advice/experience from folks who has used small 6-8
Wavelength DDWM.

Also what are the pros and cons of CDWM and DDWM?

Application;  5 Mile Dark Fiber between two carrier neutral hotels in SF.

All help is appreciated and results will be shared if requested.


      I think the biggest difference between small DWDM and CWDM is how much
growth room you need.

      If you need 8 wavelengths (possibly 16 is still called CWDM but I doubt
you can stay on the CWDM side. The lasers and the gear is generally cheaper.

      With DWDM gear everything seems to be more expensive, but you get a lot
more control as the electronics governing the chassis' tend to be much more
advanced. On a short run like that, many advanced features like all-optical
amplification and such are not necessary. I am not aware of any all-optical
CWDM amplifiers yet. (for example).

      If you are planning more than just 1 DF run, you could buy the less
expensive solution and just swap it out when you need something more and use
the CWDM solution somewhere else.

      If you have decent/modern fiber, you should be able to comfortable sign
8 waves x 1G or 8 x 2.5G (full duplex). Some DWDM gear will let you double
that on just 8 colors by going full duplex on each fiber (each thread).

      So its a question of how much BW you need and how much you want to pay
for right now.

      (If I am wrong, someone please correct me).

Hope this helps, let me know what you decide.

I would be interested in recommendations for specific hardware.  We
are looking at longer runs and the units must be NEBS compliant as the
nodes are in telco COs.


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