ODMRP

Abstract: In this paper, we present a multicast protocol which is built upon the temporally-ordered routing algorithm (TORA). The protocol-termed the lightweight adaptive multicast (LAM) routing algorithm-is designed for use in a Mobile Ad hoc NETwork (MANET) and, conceptually, can be thought of as an integration of the CORE based tree (CBT) multicast routing protocol and TORA. The direct coupling of LAM and TORA increases reaction efficiency (lowering protocol control overhead) as the new protocol can benefit from TORA's mechanisms while reacting to topological changes. Also during periods of stable topology and constant group membership, the LAM protocol does not introduce any additional overhead because it does not require timer-based messaging during its execution.

Abstract: We present the protocol for unified multicasting through announcements (PUMA) in ad-hoc networks, which establishes and maintains a shared mesh for each multicast group, without requiring a unicast routing protocol or the preassignment of cores to groups. PUMA achieves a high data delivery ratio with very limited control overhead, which is almost constant for a wide range of network conditions. Using simulations in Qualnet 3.5, we compare PUMA with ODMRP and MAODV, which are representatives of mesh-based and tree-based multicast routing in ad hoc networks. The results from a wide range of scenarios of varying mobility, group members, number of senders, traffic load, and number of multicast groups show that PUMA attains higher packet delivery ratios than ODMRP and MAODV, while incurring far less control overhead.

Abstract: Multicasting has emerged as one of the most focused areas in the field of networking. As the technology and popularity of the Internet grow, applications such as video conferencing that require the multicast feature are becoming more widespread. Another interesting development has been the emergence of dynamically reconfigurable wireless ad hoc networks to interconnect mobile users for applications ranging from disaster recovery to distributed collaborative computing. In this article we describe the on-demand multicast routing protocol for mobile ad hoc networks. ODMRP is a mesh-based, rather than conventional tree-based, multicast scheme and uses a forwarding group concept (only a subset of nodes forwards the multicast packets packets via scoped flooding). It applies on-demand procedures to dynamically build routes and maintain multicast group membership. We also describe our implementation of the protocol in a real laptop testbed.

Abstract: The stationary nature of nodes in a mesh network has shifted the main design goal of routing protocols from maintaining connectivity between source and destination nodes to finding high-throughput paths between them. In recent years, numerous link-quality-based routing metrics have been proposed for choosing high-throughput paths for unicast protocols. In this paper we study routing metrics for high-throughput tree or mesh construction in multicast protocols. We show that there is a fundamental difference between unicast and multicast routing in how data packets are transmitted at the link layer, and accordingly there is a difference in how the routing metrics for each of these primitives are designed. We adapt certain routing metrics for unicast for high-throughput multicast routing and propose news ones not previously used for high-throughput. We then study the performance improvement achieved by using different link-quality-based routing metrics via extensive simulation and experiments on a mesh network testbed, using ODMRP as a representative multicast protocol. Our testbed experiment results show that ODMRP enhanced with linkquality routing metrics can achieve up to 17.5% throughput improvement as compared to the original ODMRP.