How do you put a TV station on the Mbone?

Jeff Wheeler jsw at
Wed May 4 18:07:33 UTC 2011

On Wed, May 4, 2011 at 12:45 PM, Leigh Porter
<leigh.porter at> wrote:
> Agreed, it seems the only demand really for this live viewing is sport, news
> and background programming like the mentioned breakfast television.

I disagree with the general notion that multicast is not useful except
for live content.  Allow me to give a couple of examples that would
probably be implemented if we really had a multicast-enabled Internet,

Most of us have some number of Windows machines on our networks,
probably a large number.  These updates are pervasive, and yet they
are largely delivered to end-users as unicast downloads.  If we all
had mcast, the latest and greatest Windows Update would probably be
available via mcast, and your PC would join the appropriate group,
receive the update, and be able to install it, without any unicast
traffic at all.  There may be several groups for users who have
different access network speeds, and your machine may need to
fall-back to unicast to retrieve last week's updates or get
packets/chunks that it missed, but this is far from difficult to

While on-demand movies are unicast today, there's no reason a content
provider couldn't take advantage of multicast for the most popular
movies, let's say "new releases."  We know that the latest movies are
more popular than older titles, because they consume much more shelf
space at Blockbuster, and more storage slots in the corner RedBox.  I
might receive the first few minutes of my on-demand movie by unicast,
and "catch up" to a high-speed multicast stream which repeatedly
"plays" the same movie, faster than the real-time data rate, for users
with sufficient access speed to download it.  My set-top-box would
transition from unicast to cached data it received via mcast,
resulting in a large bandwidth savings for popular titles.

As you can see, multicast can be useful for distribution of popular
time-shifted content and data, not just sports, news, and traditional
live programming.  Whether or not we ever see wide adoption of
multicast support on end-user access networks, well, that seems
increasingly unlikely given the consolidation of ISP/last-mile and
content producers/owners.  The less ISP networks look like "common
carriers" from a business perspective, the less motive they have to
act like a common carrier, and provide efficient, cost-effective
access to anything users wish to download.

For someone like Comcast, multicast is the ultimate "boogie man."
End-users being able to originate content at low cost to anyone and
everyone, without expensive CDNs or network connectivity?  I could
start my own movie channel, license some indie films I want to stream,
throw some ads over them, and be in competition with traditional
television networks who pay for satellite transponders, negotiate for
carriage, etc.  There is no way a Comcast/NBC Universal would ever
make the mistake of giving their users unfettered access to multicast.

Jeff S Wheeler <jsw at>
Sr Network Operator  /  Innovative Network Concepts

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