A swarm-based hybrid routing protocol to support multiple Quality of Service (QoS) metrics in mobile ad hoc networks

Quality of Service support in routing for Mobile Ad hoc Networks (MANETs) is a challenging process because of the limitation on available resources and the dynamic topology. The main purpose of QoS routing is to find a feasible path that has sufficient resources to satisfy the constraints. A fundamental problem in QoS routing is to find a path between a source and destination that satisfies two or more end-to-end QoS constraints/metrics. Considering more than two metrics involves more computational complexity and it is proved to be NP-complete problem. Stochastic optimization techniques are better solutions for these kinds of problems. A routing model can be chosen either as proactive or reactive. Purely proactive protocols are not optimal for rapidly changing topologies and purely reactive protocols are often inappropriate for relatively static networks. In addition, reactive protocols also suffer with additional delay for real-time traffic. In such scenarios, hybrid routing is proven to improve on purely reactive-routing or purely proactive-routing if most traffic is localized. In order to achieve routing efficiency in such environment, a hybrid routing strategy is proposed which combines the advantages of both proactive and reactive mechanisms. In this paper, a novel QoS routing strategy called Swarm-based Hybrid Routing Protocol (SHRP) based on ant colony optimization is proposed to support the three metrics such as end-to-end delay, bandwidth and hop count. To evaluate the performance of SHRP, a series of simulations are carried out with the simulator QualNet. The simulation results of SHRP are compared with the hybrid routing protocols ZRP and HOPNET. Through the simulation results, it has been showed that SHRP fabricates better performance than ZRP and HOPNET in terms of packet delivery ratio, throughput, end-to-end delay, bandwidth and hopcount.