Hot Diggety! da...@lang.hm was rumored to have written: > > When you move to routing it gets even more complicated because you can no > longer start with the 'send it everywhere and filter what's not needed'
What you just described is PIM (DM) -- Protocol Independent Multicast [dense mode]. Doesn't scale well for that very reason. But the flip side is PIM (SM) [sparse mode] where it builds these tables based on expressed subscriber interest. > approach (as that would send packets through everyone's links), you need a > way to tell a router 'I am interested in this multicast stream', and > then that router needs to tell it's adjacent routers what it's interested > in, etc until it finally reaches a router that knows about that particular > multicast stream. If paths change between the points, the new routers > involved need to know enough to send that multicast stream to the router. There's also MSDP (Multicast Source Discovery Protocol), which is designed to address the problem of cross-provider multicast. This basically allows each provider to maintain its own local multicast confederation by using something called RPs (Rendezvous Points) and then MSDP extends that by facilitating RP-to-RP communications across providers. With that said, I haven't directly worked with multicast recently, and don't pretend to hold a CCIE or CCA cert. :-) (So I reserve the right to be wrong. :-) ) -Dan _______________________________________________ Discuss mailing list Discuss@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
