TransAtlantic 40 Gig Waves

Rod Beck Rod.Beck at
Fri Aug 14 09:30:34 CDT 2009

-----Original Message-----
From: Richard A Steenbergen [mailto:ras at]
Sent: Fri 8/14/2009 2:17 PM
To: Rod Beck
Cc: Matthew Moyle-Croft; nanog at
Subject: Re: TransAtlantic 40 Gig Waves
On Fri, Aug 14, 2009 at 10:14:59AM +0100, Rod Beck wrote:
> Obviously using 40 gig waves as the foundation blocks of one's network
> provides some economies of scale and per unit capex cost savings. 
> I would be curious if anyone knows how to convert this SONET/SDH 40
> gig waves into a 40 gig Ethernet handoff? 
> Afterall, OC768 route cards are a tad expensive ...

I'm not aware of any solution that isn't going to be a lot more
expensive than just using the native OC768 card (which isn't "that"
expensive in crazy bankrupt carrier dollars, it's just not in the same
ballpark as 10GE solutions). This in turn is going to be a lot more 
expensive than just running 4x10GE, for the moment. Of course native 
40GE is in the works, so eventually this will make technical and 
financial sense, just not yet. But this is one of the major reasons I've 
been a proponent of 40GE standardization instead of focusing solely on 
100GE, 40 maps directly to the next-generation optical technology and 
allows you to efficiently and affordably transport ethernet over long 
distances, whereas 100 is largely just a fancy cable management solution 
for hiding multiple parallel links (i.e. 10x10G) within a datacenter.

Rod, do you know if the 40G waves increased the spectrum efficiency of 
your fiber? On land systems they pretty much break even, i.e. you can 
have a 100GHz 40G channels or 4x25GHz 10G channels but at the end of the 
day you still get the same amount of signal out of the fiber. I don't 
know whats being done on undersea cables though. Eventually this will 
get better too, and 40G will become the "native" wavelength standard 
with 10G being muxed onto them, similar to what we saw with the 
transition from 2.5G->10G 10 years ago.

Richard A Steenbergen <ras at>
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)

Agreed. I think it was a mistake to put all the effort into 100 GigE when it is not even clear a lot of fibre can support 100 Gig waves. As I understand the bit rate depends on the geometrical properties of the fibre. 

And yes, IP engineers are telling me is that there are no economically viable 40 gig SONET/Ethernet conversion boxes. 

My understanding is that we are getting a big spectrum efficiency gain. The press release states the system's potential is 10.16 terabits. Before the upgrade, it was 6.4 terabits or 80 10 gig waves per fibre pair (two cables, four fiber pairs each). I will check that figure. 

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