A Scalable and Secure Position-Based Routing Protocol for MANETs Liana Khamis Qabajeh, Miss Laiha Mat Kiah Faculty of Computer Science and IT University of Malaya Kuala Lumpur, Malaysia Mohammad Moustafa Qabajeh Department of Electrical and Computer Engineering IIUM Kuala Lumpur, Malaysia Abstract—Mobile Ad-Hoc Networks (MANETs) are becoming increasingly applicable in different fields. Securing MANETs routing protocols is considered as one of the most difficult areas to deal with as opponents can add themselves to a MANET using the existing common routing protocols. This paper proposes a new routing protocol; ARANz, which is an extension of the original Authenticated Routing for Ad-Hoc Networks (ARAN). Apart from the authentication methods adopted from ARAN, ARANz aims to increase security, achieve robustness and solve the single point of attack and failure problems by introducing multiple local certificate authority servers. Via dealing with the network as zones and using restricted directional flooding, our new model exhibits better scalability and performance. Through simulation we evaluated ARANz and compared it with the original ARAN. Simulation results show that ARANz is able to effectively and efficiently discover secure routes within relatively large networks with large number of mobile nodes. Keywords-Secure; Scalable; Position-Based; Routing; Ad- Hoc Network; MANETs I. INTRODUCTION Mobile Ad-Hoc Network (MANET) is a self- configuring network of mobile devices connected by wireless links. A key component of Ad-Hoc networks is an efficient routing protocol since all devices in the network act as routers. Another important issue is securing the routing protocol specially that the concept and structure of Ad-Hoc networks make them prone to be easily attacked. Many secure routing protocols have been developed for Ad-Hoc networks such as the Authenticated Routing for Ad- Hoc Networks (ARAN) [1]. ARAN provides authenticated route discovery, setup and maintenance. Main objective of ARAN is to protect against attacks from malicious nodes in a managed-open environment where a small amount of prior security coordination is expected. Before entering the Ad- Hoc network each node requests a certificate from a trusted certificate authority. Every node that forwards a request or a reply must sign it so that the successor node can check the validity of the previous one. We observed that although ARAN is robust against a large number of attacks, it bases on a centralized trust hence suffers from the single point of failure and attack problems as well as a scalability problem since route request packets are flooded to the entire network. Recently, position-based routing protocols exhibit high scalability, performance and robustness against frequent topological changes. Position-based routing protocols use the geographical position of nodes to make routing decisions. Hence, the source node is supposed to obtain its own geographical position as well as the destination’s position. Usually, this information is obtained via Global Positioning System (GPS) and location services. Position-based routing protocols are categorized into three main groups: restricted directional flooding, greedy forwarding and hierarchical routing protocols. We note that restricted directional flooding has better performance than topology- based and other position-based routing protocols. Moreover, limited work has been done to secure position-based routing. Consequently, it is an important issue to find a scalable and secure position-based routing protocol for Ad-Hoc networks. A new model of hierarchal and distributed routing protocol, ARANz has been proposed in this work. Through simulation we evaluated ARANz and compared it with the original ARAN. Preliminary results show that ARANz is able to discover secure routes efficiently within relatively large networks having large number of nodes. The rest of the paper is organized as follows. Section II presents the newly proposed protocol. Section III contains simulated comparison between ARAN and ARANz protocols. We analyze and discuss our findings in Section IV. Section V presents our conclusions and future directions. II. PROPOSED PROTOCOL In this section a new routing scheme is proposed. The proposed protocol is named ARANz since it adopts the authentication steps used with the ARAN protocol and deals with the network as zones. ARANz uses cryptographic certificates to prevent most of the attacks against Ad-Hoc routing protocols and detect erratic behavior. ARANz introduces a hierarchal distributed routing algorithm, which aims to improve performance of the routing protocol and distribute load by dividing the area into zones. It aims to achieve robustness, solve the single point of failure problem and avoid the single point of attack problem by distributing trust among multiple Local Certificate Authority (LCA) servers. Each zone has multiple LCAs that collaborate together to issue certificates for nodes inside that zone. ARANz tries to exhibit better scalability, performance and robustness against frequent topological changes by using restricted directional flooding. Whenever a node needs to communicate with another one the former will get the latter’s position through the LCAs of its zone, then the route request Annual International Conference on Network Technologies & Communications (NTC 2010) Copyright © GSTF 2010 ISBN: 978-981-08-7656-2 doi:10.5176/978-981-08-7656-2 NTC2010-9 N-7