/. Terabit Ethernet is Dead, for Now

tom at ninjabadger.net tom at ninjabadger.net
Mon Oct 1 09:58:36 UTC 2012


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-adva-optical-networkings-100g-metro-solution/

>> 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



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