IRACST – International Journal of Computer Networks and Wireless Communications (IJCNWC), ISSN: 2250-3501 Vol.6, No 1, Jan-Feb 2016 14 Ant-Hoc: A swarm intelligence-based routing protocol for Ad Hoc networks Essam H Houssein Dept. of Computer Science Faculty of Computers and Information Minia University El Minia - Egypt essam.halim@mu.edu.eg Diaa S AbdElminaam Dept. of Information Systems Faculty of Computers and Informatics Benha University Benha - Egypt diaa.salama@fci.bu.edu.eg Alaa A. K. Ismaeel Dept. of Computer Science Faculty of Science Minia University El Minia - Egypt alaa.ismaeel@mu.edu.eg ABSTRACT- A mobile ad hoc network (MANET) is a collection of wireless mobile nodes communicating with each other using multi- hop wireless links without any existing network infrastructure or centralized administration. One of the main challenges MANET is the design of robust routing algorithms that adapt to the frequent and randomly changing network topology. Nature-inspired algorithms (swarm intelligence) such as ant colony optimization (ACO) algorithms have shown to be a good technique for developing routing algorithms for MANETs. In this paper, we propose a new routing protocol for MANETs called Ant-Hoc which based on ACO, proactive and reactive routing protocol capability. Using the simulation model with a dynamic network size and an invariable pause time which should be zero under weakest case because a longer pause time of the node may be insignificant for MANET with frequently and fast moving nodes. Furthermore, based on the QoS, routing load and the connectivity, this paper systematically discuses the performance evaluation and comparison of Ant-Hoc and three typical routing protocols of MANETs with the different simulation model and metrics. Results indicate that Ant-Hoc effectively improve the connectivity, packet delivery ratio and reduce the end-to-end delay as compared with the AntNet, AODV and DSDV routing protocols. Keywords: MANETs; Performance evaluation; QoS; Network simulation; Routing protocols; AODV; DSDV; ACO. I.INTRODUCTION A mobile ad hoc networks (MANETs) consisting of a collection of mobile nodes (MNs) sharing a wireless channel without any centralized control or established communication backbone. MANETs have no fixed routers; all nodes are capable of movement and can be connected dynamically in an arbitrary manner. Usually, these nodes act as both end systems and routers at the same time. Nodes of these networks, which function as routers, discover and maintain routes to other nodes in the network. The topology of the MANET depends on the transmission power of the nodes and the location of the MNs, which may change with time. A working group namely "MANET" has been formed by the Internet Engineering Task Force (IETF) to study the related issues and stimulated research in MANETs [29]. A fundamental problem in MANET is how to deliver packets among MNs efficiently without predetermined topology or centralized control, which is the main objective of routing protocols. Since MANETs change their topology frequently, routing in such networks is a challenging task. So far, much work has been done on routing in MANETs and can be divided into: proactive protocols and reactive protocols [10]. Proactive routing protocol includes: Destination Sequenced Distance Vector (DSDV) and Fisheye State Routing (FSR) etc. They attempt to maintain a correct view of the network topology add the time and build routes from each node to every other node before they are needed, hence they are also called table-driven protocols. Any changes in topology are propagated through the network, so that all nodes know of the changes in topology. Thereby, proactive protocols maintain routing information about the available paths in the network even if these paths are not currently used. The major drawback of these approaches is that the maintenance of unused paths may occupy an important part of the available bandwidth if the topology of the network changes frequently [29]. Reactive routing protocols includes: Ad hoc On-demand Distance Vector (AODV) Routing and Dynamic Source Routing Protocol (DSR) etc. Reactive routing protocols maintain only the routes that are currently in use, thereby trying to maintain low control overhead, reducing the load on the network when only a small subset of all available routes is in use at any time. However, they still have some inherent limitations. First, since routes are only maintained while in use, it is usually required to perform a route discovery before packets can be exchanged between communication peers. This leads to a delay for the first packet to be transmitted. Second, even though route maintenance for reactive algorithms is restricted to the routes currently in use, it may still generate an important amount of network traffic when the topology of the network changes frequently. Finally, packets to the destination are likely to be lost if the route to the destination changes [3]. Several performance studies [1, 4, 9, 17, 18, 25 and 28] of MANETs have built and utilize only one single route for each pair of source and destination nodes. Due to node mobility, node failures, and the dynamic characteristics of the radio channel, links in a route may become temporarily unavailable, making the route invalid. The overhead of finding alternative routes may be high and extra delay in packet delivery may be introduced. Multipath routing addresses this problem by providing more than one route to a destination node. Source and intermediate nodes can use these routes as primary and backup routes. High route discovery latency together with frequency route discovery attempts in dynamic networks can affect the performance adversely. Multipath protocols try to alleviate these problems by computing multiple paths in a single route discovery attempt. Multiple paths could be formed at both traffic sources as well as at intermediate nodes. New route discovery is needed only when all paths fail. This reduces both route discovery latency and routing overhead.