A Hybrid Overlay Multicast Routing Protocol for MANETs

• Main Authors: Chaung-Kai Chen, 陳琮闓
• Other Authors: Kuochen Wang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/94411208294316334286

碩士 === 國立交通大學 === 資訊科學系所 === 92 === We propose a novel multicast routing protocol, called hybrid overlay multicast routing protocol (HOMRP) for MANETs (Mobile Ad hoc NETworks). Existing overlay multicast routing protocols in MANETs have the main drawback of high packet delivery delay. In order to improve this shortcoming, we integrate multicasting and unicast tunnels for efficient packet delivery. In HOMRP, it creates multiple local multicast trees. Each pair of parent node and child node in a local multicast tree is at a distance of one-hop. It uses multicasting to deliver multicast packets in local multicast trees. This will provide efficient data forwarding. Unicast tunnels are used for transmitting packets between local multicast trees. To avoid looping routes between local multicast trees, each local multicast tree is assigned a tree ID. To deal with dynamic changing of network topology in MANETs, HOMRP uses a tree consolidation scheme for highly efficient data forwarding. In addition, in order to reduce the overhead of control messages flooding, we adopt two-level flooding for member discovery by limiting the value of TTL in a packet. HOMRP does not restrict to use any specific unicast routing protocol; hence it can operate with any unicast routing protocols. Route maintenance in HOMRP is initiated by each multicast group member. Each member only needs to maintain the nearby members. The same route structure of a multicast group can be shared by multiple senders (sources); this brings high efficiency of route maintenance. Simulation results have shown that the packet delivery ratio of HOMRP is close to that of ODMRP and is 50% better than that of AMRoute. HOMRP reduces 18% control overhead compared to ODMRP and reduces 9% end-to-end packet delay compared to AMRoute. In sum, HOMRP provides lower control overhead, high packet delivery ratio and is especially suitable for multicast applications with larger number of senders, compared to other approaches.