Comparative Performance Study of ADMR and ODMRP in the context of Wireless LANs and Wireless Sensor Networks RADOSVETA SOKULLU, OZLEM KARACA Ege University, Department of Electrical and Electronics Engineering Ege University, Izmir TURKEY Abstract: - Wireless LANs (WLANs) and Wireless Sensor Networks (WSNs) are two large groups of networks that have well established application ranges. Despite the fact that they address very distinctive groups of devices and have clearly differentiated wireless interfaces, there are certain similarities which push scientists to look for adopting solutions already designed for WLANs to WSNs. An example of this is the case with routing layer protocols. AODV, an unicast routing protocol, developed for Mobile Ad Hoc networks (MANET), has proved to be applicable and accepted by IEEE as the standard for the routing layer in Low Rate – Wireless Personal Area Networks (LR-WPAN). Still, MANET-originated solutions, including multicast protocols, were initially designed in the context of IEEE 802.11 MAC layer protocol. This paper investigates the feasibility of two popular MANET multicast protocols, ADMR and ODMRP over the IEEE 802.15.4 standard and provides a comprehensive study of the performance of these two protocols with different underlying physical and media access protocols. The protocols have been analyzed with ns-2 network simulator. It appears that even though both protocols are applicable in the selected scenarios, there are specifics in their performance in the context of WSNs which should not be neglected. Key-Words: - wireless sensor networks, medium access control mechanisms, wireless LANs, performance evaluation 1 Introduction Wireless sensor networks (WSNs) enhanced with actuator capabilities materialize the interface between people and the environment and establish a context for assisted living and emergency measures, intelligent production and transport, and environmental monitoring. Existing solutions in different OSI layers, designed initially for MANETS, are tested for their applicability in WSNs. An example is the adoption of AODV as a routing protocol for LR-WPAN. The focus of this paper is further investigating such solutions, like ADMR and ODMRP, which are multicast protocols originally designed for MANETs, in the context of WSN application scenarios and performance requirements. An open question is whether the multicast supporting functions of routing protocols developed for MANETS like ADMR and ODMRP can be used for WSNs. Need for such functions has been seen in many WSN based application scenarios like in the health sector where vital patient information is collected by wireless sensors and transmitted to only interested or responsible personnel (doctors, nurses involved with a certain patient [1]), tracking of fire-fighters in burning buildings, data collection with mobile sensors, disaster rescue etc. These scenarios require more general topologies than the event- to-sink model usually accepted for WSNs. When comparing the two protocols the underlying media access mechanism has been taken into consideration and IEEE 802.11 and IEEE 802.15.4 have been covered. The paper is structured as follows: the next two sections provide a brief background on the specifics of the protocols that are investigated, first for the medium access control and then for the routing layer. In Section 4 the simulation model and the methodology use is discussed. In Section 5 the simulation results are presented followed by conclusions in Section 6, which summarize the most important contributions of the work. 2 Specifics of the IEEE 802.11 and IEEE 802.15.4 MAC Layer Protocols Both protocols have been standardized by IEEE for the physical (PHY) and media access control (MAC) layer of wireless networks but aiming at different types of wireless devices and network configurations. The 802.11 addresses wireless networks consisting of laptops or similar class of devices, in either infrastructure or infrastructure-less (Ad Hoc) mode. The 802.15.4 set of protocols is developed in the LR-WPAN working group and addresses low speed, low data rate and very resource restricted devices, targeting the case of networking wireless sensor nodes. The paper concentrates on the performance comparison of two different multicast routing protocols, originally suggested for Ad Hoc networks, ADMR and ODMRP, using different underlying MAC layer protocols, specifically IEEE 7th WSEAS Int. Conf. on TELECOMMUNICATIONS and INFORMATICS (TELE-INFO '08), Istanbul, Turkey, May 27-30, 2008. ISBN: 978-960-6766-64-0 183 ISSN: 1790-5117