IP Multicasting in Hybrid Networks
The asymmetric nature of traffic in most networks, as evident in the Internet, is shifting current networking technology trends more towards the development of hybrid networks. Multimedia traffic with its inherent variability in Quality of Service (QoS) requirements further reinforces this trend. Technologies such as DirecPC which allow users to send traffic terrestrially and receive traffic through satellite have demonstrated the efficiency of the broadcast nature of satellite communications as a means of delivering high bandwidth traffic to end users. Even though the majority of Internet applications rely on point-to- point transmission (unicast), emerging applications such as teleconferencing and information distribution have necessitated the development of an overlay multicast backbone network in the Internet (MBONE) for point/multipoint-to-multipoint data transmission. A major hurdle in multicasting over the Internet is the potential for high bandwidth traffic to cause congestion in the terrestrial backbone. Introducing hybrid terminals within corporate LANs for incoming multicast streams thus would provide an effective means of preserving gateway bandwidth for other outgoing traffic.