The era of 1990s marked a rapid growth of research interest in mobile ad hoc networking. Mobile Ad hoc Networks (MANETs) employ the traditional TCP/IP protocol structure which provides endto- end communication between two different nodes. Routing is one of the interesting research areas in MANET. It has received a tremendous amount of attention from researches. This helps in the development of different routing protocols for MANETs. Therefore, it is quite difficult to determine which protocol perform best under a number of different network scenarios, such as increasing node density and traffic. This paper provides an overview of a wide range of on-demand routing protocols proposed in the literature, presents a qualitative analysis of on-demand routing protocols and suggests which protocol performs best in large networks. In qualitative analysis, the properties are compared according to different criteria and then listed the advantages and disadvantages of the each protocol. Protocols considered here are on-demand routing protocols, as these are best suited for ad hoc environment.

Nowadays, the importance of exchange digital information from outside the typical wired office environment is growing (http://www.monarch.cs.rice.edu/monarch-papers/ dmaltz-thesis.pdf). For example, a class of students may need to interact during a lecture; business associates serendipitous meeting in an airport may wish to share files; or disaster recovery personnel may need to coordinate relief information after a hurricane or flood. Each of the devices used by these information producers and consumers can be considered a node in an ad hoc network. To exchange the information in a typical ad hoc network, mobile nodes come together for a period of time. While exchanging information, the nodes may continue to move, and so the network must be prepared to adapt continually. Networking infrastructure, such as repeaters or base stations are frequently be either undesirable or not directly reachable, so the nodes must be prepared to organize themselves into a network and establish routes among themselves without any outside support. The idea of ad hoc networking is sometimes also called ‘infrastructureless networking’ (National Science Foundation, 1997) since the mobile nodes in the network dynamically establish routing among themselves to form their own network ‘on the fly’.

This paper makes a comparison of these protocols and then discusses the merits and demerits associated with each on-demand ad hoc routing protocols.

Large networks consisting of nodes with limited resources are complex and present many challenges that are not solved in areas such as addressing, routing, location management, configuration management, interoperability, security and high capacity wireless technologies, so Mobile Ad hoc Networks (MANETs) have made designing of an efficient and reliable routing strategy a very challenging problem. By the efficient use of the limited resources, while at the same time being adaptable to the changing network conditions, such as network size, traffic density and network partitioning. In parallel with this, the routing protocol may need to provide different levels of Quality of Service (QoS) to different types of applications and users.

Computer Sciences Journal, Routing Protocols, Ad Hoc Networks, Mobile Ad hoc Networks, Infrastructureless Networking, Configuration Management, Wireless Technologies, Dynamic Source Routing, Directed Acyclic Graph, Relative Distance Micro Discovery, Static Routing Protocol, Dynamic Routing Protocol, Global Positioning System.