An IP multicast - HTTP Gateway for reliable streaming in heterogeneous networks

IP multicast has proved to be the best approach for large scale multimedia communications enhancing video transmissions for applications like IPTV, video conferencing or other best-effort real-time audio/video applications. IP multicast connectivity, unfortunately, relays on certain network technologies and protocols and is present only in some areas of the Internet, while the majority of hosts lack in such connectivity and do not have sufficient network resources, or are locked behind firewalls. In this paper we present an effort to design and implement a HTTP Gateway for IP multicast communications. The main objective is to allow connections to IP multicast subsystems from different locations over Internet by tunneling multicast traffic over HTTP protocol. This way, the content of multicast network is easily accessible and independent of transport network. Another important goal of our gateway design is the optimization mechanism based on cache overriding to cope with network congestions. It is well known that TCP video streaming amplify the network congestions. Our proposed solution implements an intelligent buffering mechanism based on packet discarding rather then connection dropping.