nanog mailing list archives

Re: death of the net predicted by deloitte -- film at 11


From: Hank Nussbacher <hank () efes iucc ac il>
Date: Tue, 13 Feb 2007 07:37:22 +0200 (IST)


On Mon, 12 Feb 2007, Peter Beckman wrote:

NBC can now stream their shows to me as a .mp4 and I could grab them as
fast as they could send it, rather than in realtime.  They might offer the
same stream at different data rates: 1mbps, 5mbps, 10mbps, 30mbps (for
those of us lucky enough to have Verizon FIOS at home).  The streams would
simply repeat once they streamed all the files in a list.

That is what layered IPmc is. There is a base stream and on top of that additional "layers" are interleaved and you pick up just what you need - depending on your b/w. There are other facets to layered IPmc such as staggered streams, whereby the same VOD is transmitted 10x an hour, at 6 minute intervals and using clever encoding you "tap" into the multicast stream and within an average of 3 minutes your VOD starts playing - at the level of quality based on your available b/w.

I've seen this in action as far back as 1998 and just don't quite grok why it never took off.

-Hank


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