Most content providers don't want multicast because it breaks their
billing model. They can't tell how many viewers they have at a given
moment, what the average viewing time is, or any of the other things
that unicast allows them to determine and more importantly bill their
advertisers for. There is no Nielsen's Ratings for multicast so that
advertisers could get a feel for how many eyeballs they are going to
hit.
So why cant the data and control plane be separate for content delivery?
Use multicast for the data part, but stick with unicast for the control.
In other words, end-users will still need to explicitly register/deregister with
content providers to receive content. This will allow the content providers to do
everything they could do previously with unicast data. except now
end-users will receive the content over the multicast tree.
Of course the ISPs will also have to somehow separate the data and control plane,
so their billing issues with multicast can be addressed...
Rajesh.