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.
This is true but you should probably define your network size. I don't see many/any independents doing this because of the cost of the boxes and dealing with the content providers. If you're a large MSO (say top 15) then I can see it with today's technology, but even those guys seem to be moving in other directions to get out of the provider controlled set top box model.
S
-- Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking
-- Scott Helms Vice President of Technology ZCorum (678) 507-5000 -------------------------------- http://twitter.com/kscotthelms --------------------------------