International Journals of Advanced Information Science and Technology (IJAIST)
Group communications are important in Mobile Ad hoc NETworks (MANETs). Multicast is an efficient method for implementing group communications. However, it is challenging to implement efficient and scalable multicast in MANET due to the difficulty in group membership management. Efficient Geographic Multicast Protocol (EGMP) uses a virtual-zone-based structure to implement scalable and efficient group membership management. A network wide zone-based bidirectional tree is constructed to achieve more efficient membership management and multicast delivery. EGMP has high packet delivery ratio, and low control overhead. But it has some delay.