nanog mailing list archives

Re: The scale of streaming video on the Internet.


From: Owen DeLong <owen () delong com>
Date: Thu, 2 Dec 2010 13:02:37 -0800


On Dec 2, 2010, at 12:48 PM, Jay Ashworth wrote:

----- Original Message -----
From: "Leo Bicknell" <bicknell () ufp org>
[...] 
That's an interesting number, but let's run back the other way.
Consider what happens if folks cut the cord, and watch Internet
only TV. I went and found some TV ratings:

http://tvbythenumbers.zap2it.com/2010/11/30/tv-ratings-broadcast-top-25-sunday-night-football-dancing-with-the-stars-finale-two-and-a-half-men-ncis-top-week-10-viewing/73784

Sunday Night Football at the top last week, with 7.1% of US homes
watching. That's over 23 times as many folks watching as the 0.3% in
our previous math! Ok, 23 times 150Gbps.

3.45Tb/s.

Yowzer. That's a lot of data. 345 10GE ports for a SINGLE TV show.

But that's 7.1% of homes, so scale up to 100% of homes and you get
48Tb/sec, that's right 4830 simultaneous 10GE's if all of Comcast's
existing high speed subs dropped cable and watched the same shows over
the Internet.

I think we all know that streaming video is large. Putting the real
numbers to it shows the real engineering challenges on both sides,
generating and sinking the content, and why companies are fighting so
much over it.

It also proves, though I doubt anyone important is listening, *why the
network broadcast architecture is shaped the way it is*, and it implies,
*to* anyone important who is listening, just how bad a fit that is for
a point- or even multi-point server to viewers environment.

Yes and no... The existing system  is a multi-point (transmission towers)
to viewers (multicast) environment. No reason that isn't feasible on the
internet as well.

Oh: and all the extra servers and switches necessary to set that up?

For equivalent service (linear programming), no need. For VOD, turns
out to be basically identical anyway.

*Way* more power than the equivalent transmitters and TV sets.  Even if 
you add in the cable headends, I suspect.

Not if you allow for multicast.

In other news: viewers will tolerate Buffering... to watch last night's
daily show.  They will *not* tolerate it while they're waiting to see if
the winning hit in Game 7 is fair or foul -- which means that it will 
not be possible to replace that architecture until you can do it at 
technical parity... and that's not to mention the emergency communications
uses of "real" broadcasting, which will become untenable if enough 
critical mass is drained off of said "real broadcasting" by other 
services which are only Good Enough.

Viewers already tolerate a fair amount of buffering for exactly that.
The bleepability delay and other technical requirements, the bouncing
of things off satellites, etc. all create delays in the current system.

If you keep the delay under 5s, most viewers won't actually know
the difference.

As to the emergency broadcast system, yeah, that's going to lose.

However, the reality is that things are changing and people are tending
to move towards wanting VOD based services more than linear programming.

Owen



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