Mobile multicast with routing optimization for recipient mobility

This paper explores the issues of multicasting for mobile hosts using IETF Mobile IF. Mobile IP suggests two approaches for mobile multicasting, namel y, remote subscription (MIP-RS) and bi-directional tunneling (MIP-BT). Whil e having the advantage of optimal routing efficiency, MIP-RS uses a naive j oin-and-leave policy for mobile hosts to participate in the groups of inter est and causes serious packet losses while roaming. MIP-BT is free from pac ket losses due to roaming; however, MIP-BT and its modification MoM suffer from the triangle routing problem resulting in inefficient routing and wast age of system resources. In this paper, we propose a new mobile multicastin g protocol called Mobile Multicast with Routing OPtimization (MMROP) that e mploys a modified join-and-leave mechanism, and routes the missing data seq uence due to the "out-of-synch" problem to other agents in the adjacent net works via tunneling for roaming terminals. With MMROP, the mobility agent ( foreign or home agent) in Mobile IF, in addition to mobility management, is extended to assist multicasting for mobiles. The mobility agent is not nec essarily a multicast router. From the perspective of the multicast router, the mobility agent is a group participant, and from the mobiles, the agent serves as the proxy of multicast services. As a result, MMROP enjoys no pac ket losses from roaming as in MIP-BT, and optimal routing efficiency as in MIP-RS. We also conducted a simulation study and developed a cost analytica l model to evaluate the performance of MMROP, in comparison to MIP-RS, MIP- BT, and MoM. The results demonstrate that MMROP has optimal routing efficie ncy, low delivery cost and high robustness, as compared to other approaches .