Multicast routing issues in ad hoc networks

The advent of ubiquitous computing and the proliferation of portable computing devices have raised the importance of mobile and wireless networking. At the same time, the popularity of group-oriented computing has grown tremendously. However, little has been accomplished to-date in bringing together the technologies for group-oriented communication and mobile networking. In particular, most modern wireless/mobile and ad hoc networks do not provide support for multicast communication. A major challenge lies in adapting multicast communication to environments where mobility is unlimited and outages/failures are frequent. This paper motivates the need for new multicast routing protocols aimed specifically at fully-mobile (ad hoc) networks. Our premise is that, due to their inherent broadcast capability, wireless networks are well-suited for multicast communication. Unlike the evolution of routing in wired networks, we believe that-in ad hoc networks-it is more effective to treat multicast routing as a separate problem. The paper also identifies outstanding research issues pertaining to multicast routing in mobile and ad hoc networks, and discusses one possible approach to multicast routing and packet forwarding in ad hoc networks.