Abstract:

Small group multicasts （SGM） is a main trend of future multicast. Traditional multicast protocols are not fit for very great number of SGMs, so people study protocols which are specially designed for SGM. The main idea of SGM protocols is to heavily reduce the multieast status in the routers and use  unieast to implement multieast. The paper discusses and classifies some major SGM protocols, and analyzes their characteristics. The metrics for the evaluation of SGM protocols are summarized,and finally the future trends are explored.

Key words: small group multicast scalability explicit routing