Kobayashi san;
ISP talking with you intend to charge whether sender, reciever
or both ? I guess some ISP would not like to start multicast
service, even if subscriber request it. They might sometimes
say as an excuse what you heard.
I think there are a lot of way to make a special charge for special
service without resource reservation protocol as you think, even
if you say "It is not scalable way" :)
You completely miss the point.
Because best effort service is flat rated, receivers are not motivated
to use multicast. Senders learned to have more servers. See my column
article on the most recent IPSJ magazine for details.
That's all.
Masataka Ohta