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/