Scalable Multicast Routing in Mobile Ad Hoc Networks

Abstract

Chapter 2 Encyclopedia on Ad Hoc and Ubiquitous Computing Downloaded from www.worldscientific.com by NATIONAL POLYTECHNIC INSTITUTE (IPN) on 09/08/15. For personal use only. Scalable Multicast Routing in Mobile Ad Hoc Networks Rolando Menchaca-Mendez ∗ and J.J. Garcia-Luna-Aceves † Computer Engineering Department University of California, Santa Cruz Santa Cruz, CA 95064, USA menchaca@soe.ucsc.edu Palo Alto Research Center, 3333 Coyote Hill Road Palo Alto, CA 94304, USA jj@soe.ucsc.edu In the context of mobile and ubiquitous systems there is an increasing number of applications where data has to be transmitted, not to a single node or per- son, but to dynamic groups of nodes or people. This call for efficient multicast routing protocols capable of efficiently use the available bandwidth as well as the usually restricted hardware resources such memory and power. Moreover, given the current and expected sizes of this type of networks, multicast protocols have to be designed to scale up to hundreds of nodes. Here, we describe Hydra, the first multicast routing protocol for MANETs that establishes a multicast routing structure approximating the set of source-rooted shortest-path trees from multi- cast sources to receivers, without requiring the dissemination of control packets from each source of a multicast group. Hydra accomplishes this by (a) dynam- ically electing a core for the mesh of a multicast group among the sources of the group, so that at most one control packet is disseminated in the network to announce the existence of the group and (b) aggregating multicast routing state in the nodes participating in multicast meshes, so that redundant control pack- ets are not disseminated towards the receivers of a group. We also present an improved version of PUMA which is a receiver-initiated multicast protocol that for each multicast group periodically floods a single control packet which is used to elect a core for the group and to build and maintain the multicast mesh. We present simulations results for WiFi and TDMA MAC protocols illustrating that Hydra and PUMA attain comparable or higher delivery ratios than ODMRP, but with considerably lower end-to-end delays and, in the case of Hydra, far less data overhead. Keywords: Multicast routing; mesh-based multicast protocols; scalable multicast; state aggregation; ad hoc networks.