Performance Analysis of a Multicast Protocol for Wireless Environments

Abstract

This paper presents a performance study, using both analytical modeling and simulation techniques, of a new end-to-end reliable multicast protocol for use in environments with wireless access. The proposed pro tocol, called the reliable mobile multicast protocol (RM2), divides a multicast tree into sub-trees where subcasting is applied within the relatively smaller regions using a hierarchical tree of retransmission servers (RSs). RM2 is receiver-oriented in that the transmitter does not need to know its receivers, hence offering better scalability. The Internet Group Management Protocol is used to manage group membership whereas the IETF's Mobile IP offers support to user mobility through a temporary IP address. Each RS has a retransmission subcast ad dress shared by its members which may be dynamically configured using allocation schemes such as the IETF's MADCAP. More important, RM2 uses a dynamic re transmission strategy to switch between multicast and unicast retransmission modes according to the amount of extra load generated in the network and in the wire less interfaces by packet retransmissions. It is shown through analytical modeling and simulation that RM2's dynamic adaptation is not only important but also necessary when considering mobile wireless access.