nanog mailing list archives
RE: TransAtlantic 40 Gig Waves
From: Mikael Abrahamsson <swmike () swm pp se>
Date: Tue, 18 Aug 2009 07:28:16 +0200 (CEST)
On Mon, 17 Aug 2009, Rod Beck wrote:
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.
Think of this as the natural progression equivalent to the evolution of speed over phone lines, from 300bps to 56k, ie use of DSPs to get more out of the available spectral capacity.
10G is generally pretty simple NRZ, 40/100G is much more complex using multiple bit per "baud" and/or polarization.
<http://www.ripe.net/ripe/meetings/ripe-55/presentations/lothberg-40-gb-to-my-mother.pdf> (around page 34 is where the stuff you're asking about comes in)My guess is that 100G will be available and being rolled out before 40G is widely used, thus we'll wont see much 40G in DWDM systems, at least not with the current encoding standards (because they don't fit directly into 10G systems as they have higher requirements).
-- Mikael Abrahamsson email: swmike () swm pp se
Current thread:
- Re: East Africa Fibre Connectivity- Heads up, (continued)
- Re: East Africa Fibre Connectivity- Heads up Raymond Macharia (Aug 05)
- TransAtlantic 40 Gig Waves Rod Beck (Aug 13)
- RE: TransAtlantic 40 Gig Waves Mike Callahan (Aug 13)
- Re: TransAtlantic 40 Gig Waves Joel Jaeggli (Aug 13)
- Re: TransAtlantic 40 Gig Waves Matthew Moyle-Croft (Aug 13)
- RE: TransAtlantic 40 Gig Waves Rod Beck (Aug 14)
- Re: TransAtlantic 40 Gig Waves Richard A Steenbergen (Aug 14)
- RE: TransAtlantic 40 Gig Waves Rod Beck (Aug 14)
- RE: TransAtlantic 40 Gig Waves Rod Beck (Aug 17)
- RE: TransAtlantic 40 Gig Waves Holmes,David A (Aug 17)
- RE: TransAtlantic 40 Gig Waves Mikael Abrahamsson (Aug 17)
- RE: TransAtlantic 40 Gig Waves Mike Callahan (Aug 13)
- RE: TransAtlantic 40 Gig Waves Rod Beck (Aug 14)
- Re: TransAtlantic 40 Gig Waves Valdis . Kletnieks (Aug 14)
- RE: TransAtlantic 40 Gig Waves Rod Beck (Aug 14)
- RE: TransAtlantic 40 Gig Waves Deepak Jain (Aug 14)
- Re: TransAtlantic 40 Gig Waves Jay Ess (Aug 15)
- Re: East Africa Fibre Connectivity- Heads up Raymond Macharia (Aug 18)