Multicasting the ITU MCS: integrating point-to-point and multicasttransport

摘要

Many designs for multicast transport protocols presume anhomogeneous view of the network environment they are operating in, thenlatter hiding the various networks' features from the transport layer.nHowever, knowing its underlying network characteristics enables anmulticast transport protocol to adjust itself to particular networks.nThis can be important for providing a scalable, reliable multicastntransport. A multicast group often is faced with different topologiesn(point-to-point links vs. broadcast capable networks) and differentnnetwork service qualities (e.g. packet loss probability, throughput, andndelay). For some parts of the group, network connectivity allowsnmulticasting and the usage of negative acknowledgment schemes, fornothers, point-to-point connections with positive ACKs are required.nTrying to unite both service types within a single type of transport isninefficient and often not possible at all. We present a hybrid approachnto a multicast transport that extends a standardized multicast servicenbased on point-to-point connections to be efficiently applicable innmulticast capable networks as well. A typical teleconferencing scenarionwe have in mind consists of several sites, interconnected via WANs, eachnof which may involve several participants via LANs