A Multicast Transport Protocol Design Methodology: Analysis, Implementation and Performance Evaluation

In this paper, we propose and analyze a multicast application called SOMA (SynchrOnous Multicast Application) which offers multicast file transfer service in an asymmetric intra-campus environment (several interconnected wired and wireless LAN networks interconnected through few routers). For efficient bandwidth utilization, SOMA transmits IP packets by using multicast addressing. We also propose a complete multicast transport protocol involving both, the flow and error correction algorithms. The protocol adapts the window size and the overall application transfer bitrate to the minimum network capacity, allowing synchronism and reacting quickly when congestion arises at any network router. The application behavior has been tested by simulation in a mixture of wired and wireless intra-campus networks, and intensively studied by experimentation in an intra-campus environment composed of a wired Fast Ethernet and a wireless 802.11b Ethernet connected through an Access Point router. In addition, we develop a mathematical model to validate analytically the most important protocol parameters. The methodology employed to define, analyze and evaluate this multicast protocol is, indeed, another contribution of the work and can be easily extended to other multicast protocols.