10GE CWDM

Tue Sep 2 05:21:03 UTC 2008

On Mon, 1 Sep 2008, Robert Boyle wrote:

> At 12:03 AM 8/31/2008, you wrote:
> >Currently it is my understanding the 10 Gbps signals are carried on 
> >4 x 2.5 Gbps signals that are compatible with existing CWDM and DWDM 
> >equipment. There are 40 Gbps DWDM systems and 10 Gbps lasers on 100 
> >Gbps and greater capacity systems. I agree with Alex's comments that 
> >to have 10 Gbps on a CWDM system is to have a CWDM system of at 
> >least 40 to 100 Gbps and that is very expensive today.
> 
> The only affordable CWDM 10G system I have seen although I haven't used
> it yet is a single 10G band at 1310 or 1550 with 8 additional 2.5G bands
> around it. I haven't seen any 4 band 10G CWDM boxes with XFPs for less
> than $5000 yet, but I would expect them in the next year or two - I'm
> hoping anyway. I'm out of the country at the moment and access is a bit
> too slow to look it up easily now. If you need the manufacturer, let me
> know and I'll look it up when I return.
Depending how cheap and ghetto you want to get, there's also possibility
of doing WDM on 1310/1300. I have custom-manufactured splitters filtering
1307nm +-2nm - and any given LR XFP [*1] will be either within that band
or outside [*2]. Test a bunch of them, split them into two groups, use on
the "tested" wavelength. Bunch of friends&family are using this technology
in production. This gives you an ability to do 20G with very cheap optics.

[*1] Except ones with very temperature dependent wavelength - mark them as
"warms up to 1300" and use if you don't care that your links will take
about 5 minutes to "warm up" and come up. :)

[*2] Any LX4 Xenpak would be "outside" of the band as well, and you can 
use LX4 concurrently with LR.

There are some more ghetto fabulous things you can do, described in 
http://www.nanog.org/mtg-0610/presenter-pdfs/pilosov.pdf ;)

-alex