On 2012-10-01 08:57, Masataka Ohta wrote:
Tom Hill wrote:
Once you get your head (and wallet) around that, there becomes a case for running each of your waves at 2.5x the rate they're employed at now. The remaining question is then to decide if that's cheaper than running more fibre.
It depends on distance between senders and receivers.
However, at certain distance it becomes impossible to use efficient (w.r.t. bits per symbol) encoding, because of noise of repeated EDFA amplification.
<500km not enough? https://www.de-cix.net/news-events/latest-news/news/article/de-cix-chooses-a...
Still a hard one to justify though, I agree.
For 50Gbps lane, it becomes even harder and, for 100Gbps lane, it will likely to be impossible.
Tell this to Ciena... ;) If you can afford Wave Logic 3 interfaces for your Nortel^WCiena 6500's, you'll find some pretty impressive things are actually possible, including 100G per 100GHz guide over very large distances (think Atlantic-large). Coherence appears to be the secret sauce in pushing the SnR boundaries, albeit I'm not going to pretend to even understand the physics involved, I was just lucky enough to speak to some people that do. :)
I've recently seen a presentation from EPF** (by Juniper) that was *very* interesting in the >100G race, from a technical perspective. Well worth hunting that one down if you can, as it details a lot about optic composition in future standards, optic densities/backplanes, etc.
This one?
http://www.peering-forum.eu/assets/presentations2012/JunpierEPF7.pdf
But, it does not say much about >100G.
Yes, that is the one. Slide #11 is the one I'm referring to, 'Projection of Form Factor Evolution to 400G', which is relevant to the discussion on optic densities and the push above 100G. Tom