Re: /. Terabit Ethernet is Dead, for Now

[Masataka Ohta <mohta () necom830 hpcl titech ac jp>]

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