[132890] in North American Network Operators' Group
Re: The scale of streaming video on the Internet.
daemon@ATHENA.MIT.EDU (Owen DeLong)
Thu Dec 2 15:29:36 2010
From: Owen DeLong <owen@delong.com>
In-Reply-To: <20101202202151.GA65475@ussenterprise.ufp.org>
Date: Thu, 2 Dec 2010 12:28:47 -0800
To: Leo Bicknell <bicknell@ufp.org>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
You are assuming the absence of any of the following optimizations:
1. Multicast
2. Overlay networks using P2P services (get parts of your stream
from some of your neighbors).
These are not entirely safe assumptions.
Owen
On Dec 2, 2010, at 12:21 PM, Leo Bicknell wrote:
>=20
> Hidden in the Comcast and Level 3 press release war are some
> facinating details about the scale of streaming video.
>=20
> In =
http://blog.comcast.com/2010/11/comcasts-letter-to-fcc-on-level-3.html,
> Comcast suggest that "demanded 27 to 30 new interconnection ports".
>=20
> I have to make a few assumptions, all of which I think are quite
> reasonable, but I want to lay them out:
>=20
> - "ports" means 10 Gigabit ports. 1GE's seems too small, 100GE's =
seems
> too large. I suppose there is a small chance they were thinking =
OC-48
> (2.5Gbps) ports, but those seem to be falling out of favor for cost.
> - They were provisioning for double the anticipated traffic. That is,
> if there was 10G of traffic total they would ask for 20G of ports.
> This both provides room for growth, and the fact that you can't
> perfectly balance traffic over that many ports.
> - That substantially all of that new traffic was for Netflix, or more
> accurately "streaming video" from their CDN.
>=20
> Thus in round numbers they were asking for 300Gbps of additional
> capacity across the US, to move around 150Gbps of actual traffic.
>=20
> But how many video streams is 150Gbps? Google found me this article:
> =
http://blog.streamingmedia.com/the_business_of_online_vi/2009/03/estimates=
-on-what-it-costs-netflixs-to-stream-movies.html
>=20
> It suggests that low-def is 2000Kbps, and high def is 3200Kbps. If
> we do the math, that suggests the 150Gbps could support 75,000 low
> def streams, or 46,875 high def streams. Let me round to 50,000 =
users,
> for some mix of streams.
>=20
> Comcast has around ~15 million high speed Internet subscribers (based =
on
> year old data, I'm sure it is higher), which means at peak usage =
around
> 0.3% of all Comcast high speed users would be watching.
>=20
> 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:
>=20
> =
http://tvbythenumbers.zap2it.com/2010/11/30/tv-ratings-broadcast-top-25-su=
nday-night-football-dancing-with-the-stars-finale-two-and-a-half-men-ncis-=
top-week-10-viewing/73784
>=20
> 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.
>=20
> 3.45Tb/s.
>=20
> Yowzer. That's a lot of data. 345 10GE ports for a SINGLE TV show.
>=20
> 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.
>=20
> 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 comapnies are fighting so
> much over it.
>=20
> --=20
> Leo Bicknell - bicknell@ufp.org - CCIE 3440
> PGP keys at http://www.ufp.org/~bicknell/
