On 5/4/2011 2:07 PM, Jeff Wheeler wrote:
On Wed, May 4, 2011 at 12:45 PM, Leigh Porter
<leigh.por...@ukbroadband.com> 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,
end-to-end:
WINDOWS UPDATES
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
implement.
Local caching is MUCH more efficient than having the same traffic
running in streams and depending on everyone's PC to try and update in
the same time frame.
ON-DEMAND MOVIES
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.
Same issue as above, even if I am watching the latest popular movie
moving between a multicast and unicast stream everytime I pause it to
get another beer isn't realistic. The chances that there will be a
multicast stream that will be in synch with me is not high at all.
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.
I don't think your examples demonstrate that nor do I think the service
providers, even the folks that understand what is meant by the term,
fear multicast at all. They do feel threatened by the increase in
unicast OTT video but multicast in large amounts without the layer 1/2
service provider being engaged is a long way off.
--
Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000
--------------------------------
http://twitter.com/kscotthelms
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