Design of an IP address Auto-Configuration scheme for Wireless Multi-Hop Networks

Abstract

The importance of wireless ad-hoc networks (eg wireless mesh networks) in community and commercial connectivity cannot be underestimated in view of the benefits associated with such networks. An ad-hoc network must assemble itself from any devices that happen to be nearby, and adapt as devices move in and out of wireless range. High levels of self organization will minimize the need for manual configuration. In essence, self-organization provides an out-of-the-box functionality such that very little technical expertise is required to setup a network. However, efficiently providing unique IP addresses in ad-hoc networks is still an open research question. The goal of this study, on wireless multi-hop networks, was to develop algorithms for IP address auto-configuration. These algorithms should address the following among other problems: Achieving high levels of address uniqueness without compromising on latency and communication overhead. To achieve the overall goal of this research we proposed changes to the traditional DAD procedure, the Wise-DAD protocol was proposed. We introduced state information maintenance, which is passively collected and synchronized. Passively collecting state information reduced the number of DAD trials thereby reducing latency and communication overhead. Simulations were done in NS-2 to test the performance of the proposed protocol. A comparative analysis was then conducted. Wise-DAD was compared with the Strong-DAD protocol. Experiments on the effect of network size, node density and node arrival rate on communication overhead, address uniqueness and latency were conducted. Results from the simulation experiments show that Wise-DAD outperforms Strong-DAD in all the three metrics used for performance evaluation. First, Wise-DAD showed better scalability since it performed better than Strong-DAD when network size was increased. Communication overhead in Wise-DAD was generally low whilst the latency was generally uniform. The number of IP address duplicates recorded was reasonably low. Second, Wise- DAD was not affected by node arrival rate on all the three metrics that were recorded. On the other hand, the number of address duplicates in Strong-DAD decreased as the node arrival rate was increased. Interference significantly affected communication overhead recorded in Strong-DAD. Wise-DAD, on the other hand, was not affected by interference. The number of address conflicts in both protocols showed an inverse relationship to interference. However, the number of conflicts for both protocols was significantly different; Wise-DAD recorded much less address conflicts than Strong-DAD.