Keith; > ] > one business model that might be understandable is: you should support > ] > multicast if/when it saves you enough bandwidth (over the same content > ] > being sent over separate unicast streams) to make it worth your cost. > ] > ] It means it saves nothing for receivers that they don't want to > ] receive multicast stream. > ] > ] Then, senders are not motvated to send multicast stream. > > maybe the ISPs supporting multicast could prioritize that traffic, thus > providing better service on multicast than unicast, thus providing an > incentive for receivers to use multicast over unicast. Prioritization is orthogonal to uni/mulitcast issue. Users will favour those ISPs which prioritize unicast and pay more money. Other users may use the prioritized multicast for 1:1 communication. Masataka Ohta