Multicast Traffic on Backbones

Eric A. Hall ehall at ehsco.com
Sun Jun 10 19:55:26 UTC 2001



Sean Donelan wrote:

> While I've seen many multimedia multicast applications, I haven't
> seen one which can't have its essential elements replicated by unicast
> streams.  Is there a killer-ap for multicast?

24x7 broadcast media is the obvious/visible application.

HOWEVER, most of the 24x7 media sites (CNN, etc.) are doing on-demand
video, rather than streaming a constant feed. Content providers are
treating the Internet like a VCR instead of treating it like television,
and multicasting has very little value in a VCR model.

Whether or not the Internet is suitable for a television model is unproven
at this point. I would assume that it is, and that it is likely to
eventually be used in this capacity. But it isn't yet.

There is probably a chicken-v-egg thing going on here, too. On the one
hand, content providers aren't offering 24x7 multicast feeds because there
isn't enough multicast access at the end-points. Meanwhile, carriers
aren't offering multicasting because there's no demand for it from the
content providers.

Apart from 24x7 broadcast there isn't an obvious killer app. Most of the
multicast activity is going on in the local/admin scope, with discovery
and management protocols.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/



More information about the NANOG mailing list