[156947] in North American Network Operators' Group
Re: /. Terabit Ethernet is Dead, for Now
daemon@ATHENA.MIT.EDU (Masataka Ohta)
Mon Oct 1 08:02:13 2012
Date: Mon, 01 Oct 2012 21:01:30 +0900
From: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
To: nanog@nanog.org
In-Reply-To: <90d6f59c19749e33362af6ac82023edf@ninjabadger.net>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
tom@ninjabadger.net wrote:
>> 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/
As it says:
ADVA Optical Networking's 100G Metro solution is built on
4x28G direct detection technology
and I wrote:
Still, for 100GE, under some circumstances, 100GE with 4*25G may
become less expensive than 10*10GE.
100GE over 500km could be fine.
>> 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).
I'm afraid it uses 8 or 4 lanes.
> Coherence appears to be the secret sauce in pushing the SnR boundaries,
Just +3db, which is already counted, nothing more than that.
>> 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.
As I wrote from the beginning that:
(if same plug and cable are used both for 100GE and 10*10GE).
physical form factors can be identical between 100GE (10*10G) and
10*10GE.
Thus, the point of the slide #11 is not a valid counter argument
against my point that trunked 40*10GE or 16*25GE is no worse than
actually trunked 400GE with 40*10G or 16*25G.
While slide #12 mentions 50Gbps per lane, it is too often impossible
to be as practical as the Ethernet today.
Masataka Ohta
