In considering how to support multipoint and multicast in Windows Sockets 2 a number of existing and proposed multipoint/multicast schemes (including IP-multicast, ATM point-to-multipoint connection, ST-II, T.120, H.320 (MCU), etc.) were examined. While common in some aspects, each is widely different in others. To enable a coherent discussion of the various schemes, it is valuable to first create a taxonomy that characterizes the essential attributes of each. For simplicity, the term "multipoint" will hereafter be used to represent both multipoint and multicast.