On Wed, May 4, 2011 at 12:45 PM, Leigh Porter <leigh.porter@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. 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. 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@inconcepts.biz> Sr Network Operator / Innovative Network Concepts