/. Terabit Ethernet is Dead, for Now

Mon Oct 1 07:57:19 UTC 2012

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.

> 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.

> 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.

						Masataka Ohta