AOLSR: hybrid ad hoc routing protocol based on a modified Dijkstra's algorithm

Mobile ad hoc networks (MANETs) are highly vulnerable to both link and node failures due to nodal mobility. The routing resilience against link and/or node failures needs to be enhanced to avoid the degradation of network performance. This can be achieved by multipath routing which uses multiple alternative paths to route the messages via multiple disjoint paths and result in increased bandwidth, fault-tolerance, and security. An optimized link state routing (OLSR) protocol is a proactive routing protocol. An advanced OLSR (AOLSR) protocol is proposed based on a modified Dijkstra's algorithm which enables routing in multiple paths of dense and sparse ne0074work topologies. The routing is based on the energy of nodes and links (implied from the lifetime) and the mobility of the nodes. It is a hybrid ad hoc routing protocol because it combines the proactive and reactive features. It is another form of source routing protocol which allows a sender of a data packet to partially or completely reveal the route the packets take through the network. Two cost functions are introduced to build link-disjoint or node-disjoint paths. Secondary functions, namely path recovery and loop discovery process are involved to manage the topology changes of the network. AOLSR protocol is analyzed and compared with the existing MANET routing protocols namely, dynamic source routing (DSR) and OLSR. Its performance is observed to be satisfactory in terms of average end-to-end delay, packet delivery ratio (PDR), average time in first-in-first-out (FIFO) queue, and throughput.