The 100 Gbit/s problem in your network

Fri Feb 8 16:36:08 UTC 2013

----- Original Message -----
> From: "fredrik danerklint" <fredan-nanog at fredan.se>

> > The media market has fragmented, so unless we're talking about the
> > first week in February in the US it's not all from one source or 3 or 5.
> 
> Explain further. I did not get that.

Joel is saying that the problem you posit: *everyone* wanting to watch 
the same exact thing at the same exact time, only applies to live TV, and
these days, substantially the only thing that can pull anywhere *near* 
that kind of share is the Super Bowl, which happens to occur the first
Sunday in February.  Er, Febru-ANY.  :-)

> Isn't 20 Mbit/s more than 10 Mbit/s? (If so, we're taking about
> 10 000 customers * 20 Mbit/s = 200 000 Mbit/s or 200 Gbit/s).

Sure; he was just picking a nit about your specification of the customer 
loops: those people aren't watching QHD anyway, so no sense in using it 
as an exemplar.

My understanding is there is no appreciable amount of QHD programming
available to watch anyway, and certainly nothing a) in English b) that
isn't sports.

> > On the other hand, two weekends ago I bought skyrim on steam and it
> > was delivered, all 5.5GB of it in about 20 minutes. That's not instant
> > gratification but it's acceptable.
> 
> About 40 - 50 Mbit/s. Not bad at all.
> 
> Downloading software does not have to be in real-time, like watching
> a movie, does.

Real-time is not the constraint you're looking for.  To deliver watchable
video, the average end-to-end transport bit rate must merely be higher than
the program encoding bitrate, with some extra overhead for the lack of real
QoS and other traffic on the link; receiver buffers help with this.

The only time real-time per se matters is if you're playing the same
content on multiple screens and *synchronization* matters.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274