Domain Based Hierarchical Routing for Large Heterogeneous MANETs

This paper proposes a domain based hierarchical routing for large ad hoc networks. Our approach is based on auto-configured optimized routing domains and an enhanced inter-domain routing scheme. The large heterogeneous ad-hoc network is divided into more scalable homogeneous domains where each domain can run the routing protocol that best suits its link and traffic characteristics. We here propose an inter-domain routing protocol that exploits existing messages needed to maintain the domain structure. To support heterogeneity, the inter-domain routing scheme is independent of the routing protocols running in each domain. We compare three different approaches to the inter-domain routing: a) based solely on the propagation of domain messages, b) border node based, c) dynamic border node. In this paper, OPNET simulations compare the performance of the different inter-domain routing schemes and show the benefits of the proposed approach using OLSR and DSR as intra-domain routing protocols. Results show significant reduction in protocol overhead, increased route stability and increased route availability in a dynamic heterogeneous network. It is worth mentioning that the increased route stability is not only given by the isolation of more mobile nodes from the rest in a single domain, but also by limiting the cross-layer interactions (e.g. as the routing overhead increases, collisions at the MAC layer increase and therefore more routing packets get lost).