Unicast/Multicast
MBone apps designed to work multicast
CU-SeeMe designed to work point-to-point and via reflectors
But no longer a clear dichotomy:
WhitePine CU-SeeMe can use multicast
MBone can do unicast p-to-p and reflectors
But note that CU-SeeMe/MBone can’t interwork without application level gateway.