Or you can try from the other end - doing replication on the fly, and convert existing UNICAST data streams to the multicast if (and where) it's nessesary only.
Hrmmm... Seems to me as though, in it's most optimal state, that'd be multicast? Great idea!
I am not shure if the first approach is worst or not, nut for a few years there is attempts to build multicast network over the whole internet - and it have not eny success except a few of pylot projects. Compare RealVideo auditory and multicast auditory for now... And why don't try anpther approach.
Several providers have deployed/are deploying NATIVE multicast today on their "production" IP networks today (many have had intra-domain enabled for years), and deploying inter-domain mulicast via existing direct interconnects and the MIXs. Not only is there a b/w savings, there's a huge savings on the source side as well. A primary concern is the ability of existing and new router vendors platforms to do this efficiently. The benefits are obivous though and router vendors are definitely progressing, but as with any technology, debugging and getting the protocols to a usable state, one to which SLA/SLGs can be assoicated, takes time. -danny