A reliable multicast protocol for mailbox-based mobile agent communications

In this paper, we propose a reliable multicast protocol for mobile agent communications, which is a multicast extension to our previous adaptive and reliable protocol (ARP). ARP uses the mailbox-based scheme, where each mobile agent is associated with a mailbox for message delivery. The mailbox can be decoupled from the mobile agent and migrate with lower mobility. By adjusting the system parameters such as synchronization between mobile entities and mailbox migration frequency, ARP achieves adaptability and ensures reliability. In extending ARP to group communications, we group mailboxes residing on a host and belonging to the same multicast group into a cluster, and let all mailbox clusters form a logical ring. We present a token-based algorithm and a mailbox migration algorithm to achieve atomicity and total ordering of multicast messages. Also, we prove the correctness of the protocol and discuss the performance evaluation results obtained from simulations.