sentences:  PBB can support point-to-point, point-to-multipoint and multipoint-to-multipoint networks.PBT focuses on point-to-point connectivity, and may be capable of extension to point-to-multipoint, a key technology for advanced data applications such as IPTV.PBT avoids trying to address multipoint-to-multipoint networking, as in the opinion of some of its supporters guaranteed levels of service in multipoint-to-multipoint networks are impossible.