A Contemporary Study of Application Layer Multicast Protocols in aid of Effective Communication

IP multicasting, on par with unicast, is a powerful solution to one-to-many and many-to-many communication. The challenges faced while implementing it includes slow deployment due to the infrastructure changes needed and the address resolution problem. Hence this does not suit the current growing applications over the internet such as peer-topeer file sharing system, which requires multimedia data to be transmitted across peers. End System Multicast (ESM) or the Application Layer Multicast (ALM) becomes the alternative solution to overcome the challenge of overheads incurred in the traditional multicasting. Unlike IP multicast the end system multicast does not require any infrastructure changes. This easy deployment feature helped ALM gain popularity. Many recent research works have been carried out to improve the performance of multicasting multimedia in applications such as video conferencing, Video-on-demand, gaming etc. Many protocols for ALM have been proposed by researchers taking into account the current trends in internet usage. In this article we have described a set of ALM protocols and classified them based on some of its characteristics. We have also compared its performance based on some of its properties, with the common evaluation metrics being scalability, stress, stretch and latency.