Multicast _is_ useful for filling the millions of DVRs out there with broadcast programs and for live events (eg. sports). A smart VOD = system would have my DVR download the entire program from a local cache--and then play it locally as with anything else I watch. Those caches = could be populated by multicast as well, at least for popular content. The long tail would still require some level of unicast distribution, but that is _by definition_ a tiny fraction of total demand.
One of us has a different dictionary than everyone else.
Assume I have 10 million movies in my library, and 10 million active = users. Further assume there are 10 movies being watched by 100K users = each, and 9,999,990 movies which are being watched by 1 user each.
Which has more total demand, the 10 popular movies or the long tail?
This doesn't mean Netflix or Hulu or iTunes or whatever has the = aforementioned demand curve. But it does mean my "definition" & yours = do not match.
Either way, I challenge you to prove the long tail on one of the serious = streaming services is a "tiny fraction" of total demand.
Think I have to agree with Patrick here, even if the facts were not to support him at this time. The real question is: how will video evolve? Multicast is ideally suited for small numbers of streams being delivered to wide numbers of viewers. The broadcast television distribution model worked well when only a large conglomerate could afford to produce video. Around thirty years ago, improvements in technology made it possible and reasonable for municipal cable TV systems to generate local programs. About fifteen(?) years ago, TiVo made waves with DVR's, which introduced a disruptive concept to the existing paradigm. Then ten years ago, video cameras and computer editing made it vaguely possible for a service like YouTube to evolve to serve low quality video over the low speed broadband of the day. Now? I can shoot 1080p 30fps video on my phone, edit it on a modest computer, and post it on the Internet easily. With relatively cheap hardware. But a lot of people still watch network or cable TV. And the thing I have to think is, there's going to be a battle between Big Content, who would prefer to be able to produce shows watched by lots of people (and which works for multicast), and smaller specialty content producers who will be enabled by the ease of inexpensive Internet distribution. This battle has been fought in the shadows until now, because there are not any totally awesome ways for video to be distributed to end users. Someone will invent something like InterneTiVo, which will do for Internet video what TiVo did for OTA/cable/satellite - make it easy to find the things you'd like to watch, and handle the details of getting them for you. But here's the thing. There's a growing number of people who are taking the new generation of Smart TV's and/or the smart little boxes like AppleTV, and optionally combining it with the cheap and readily available storage options (or just relying on the speed of broadband) to be able to download and watch what they want, when they want. For our household, the computation came out to: do we continue to pay DirecTV $80/month plus the $3(?) annual rate increase they had done every single year? We were happy when we started with them at $30/mo and would probably have been willing to pay that forever. But at $80, that's $960/year, and with 21 series that we watched on a semi-regular basis, which we could purchase and own for an average of less than $40 per season, that's only $840 per year, assuming that all the series put out one season per year (a false assumption these days anyways). I've talked about this to a number of people who were startled to discover that their own TV economics did not make sense. The big thing that prevents many people from doing this is just that it's so "different." Broadband providers here in the US have been reluctant to keep up with providing contemporary, industry-leading speeds, which is the other big thing to wrestle with. As network speeds increase, the value of multicast will decrease. So my point is this: to me, it really seems like worrying about video loads on networks (in terms of multicast vs unicast) is going to be a diminishing returns sort of thing: broadband networks are going to be getting faster eventually, the potential number of video sources is going to continue to grow, the diversity of what people wish to view is going to continue to grow, the number of types of video devices is going to increase, and the difficulty of causing any sort of standard implemented on a massive installed base is going to make adoption of multicast for the purpose largely irrelevant. In the long run, it's probable that nothing will change that. There will continue to be a large amount of content that could be multicast (movies, live sports, etc) but I really expect to see CDN's take on that load instead of introducing multicast to the mix... and in the meantime I hope someone invents InterneTiVo to find all the other great content. Multicast would be great, if someone would have figured out a good way to deploy it early on... but at this late point, the horse is out of the barn. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.