ABSTRACT
The OSPF routing protocol is currently the predominant IGP in use on the fixed Internet of today. This routing protocol scales “world wide”, under the assumptions of links being relatively stable, network density being rather low (relatively few adjacencies per router) and mobility being present at the edges of the networks only. Recently, work has begun towards extending the domain of OSPF to also include ad-hoc networks – i.e. dense networks, in which links are short-lived and most nodes are mobile. In this paper, we focus on the convergence of the Internet and ad-hoc networks, through extensions to the OSPF routing protocol. Based on WOSPF, a merger of the ad-hoc routing protocol OLSR and OSPF, we examine the feature of OSPF database exchange and reliable synchronisation in the context of ad-hoc networking. We find that the mechanisms, in the form present in OSPF, are not suitable for the ad-hoc domain. We propose an alternative mechanism for link-state database exchanges in wireless ad-hoc networks, aiming at furthering an adaptation of OSPF to be useful also on ad-hoc networks, and evaluate our alternative against the mechanism found in OSPF. Our proposed mechanism is specified with the following applications in mind: (i) Reliable diffusion of link-state information replacing OSPF acknowledgements 94with a mechanism suitable for mobile wireless networks; (ii) Reduced overhead for performing OSPF style database exchanges in a mobile wireless network; (iii) Reduced initialisation time when new nodes are emerging in the network; (iv) Reduced overhead and reduced convergence time when several wireless OSPF ad hoc network clouds merge.
