Abstract-Networks which function without having any centralized fixed infrastructure or central administration are called MANETs (Mobile Ad hoc Networks). These networks are formed by small or large set of mobile nodes and communicate through the wireless links. Such Networks requires best routing protocols to establish error-free and efficient communication links. MANETs has the property of dynamically changing topology due to their mobile nodes, which move from one place to another. Overall performance of MANET routing protocols depends upon various network and protocol parameters. Mobile ad hoc networks have the characteristics of self-forming and self-healing. The routing algorithms of the routing protocols ensure selection of routes and connectivity between the mobile nodes. This paper presents analysis of three well known routing protocols of MANETs, namely; AODV (Ad hoc On Demand Distance Vector), DSDV (Destination Sequenced Distance Vector) and OLSR (Optimized Link State Routing). Analyses of these routing protocols have been carried out using NS-3 (Network Simulator-3) by varying node density and node pause time. Different performance metrics such as throughput, packet delivery ratio, end to end delay, packet loss and normalized routing load have been considered for this analysis. This analysis concludes better performance of the OLSR routing protocol.

Mobile Ad-Hoc Networks (MANETs) are self-forming, self-healing new generation infrastructure less wireless networks. Principal behind these networks is multi hop radio relaying. MANETs are very useful at locations where networking infrastructure is not available. Major applications of these networks can be accessed at military and emergency rescue operations. MANETs may contain small or large set of network nodes; each and every node requires acting as host and the router. Due to random movements of the nodes, MANETs obtain dynamic network topologies. Routing protocols in MANETs are accountable for establishing efficient and error free communication paths between network nodes. Dynamic network topologies make routing challenging. In order to meet requirement of present day applications and to overcome from routing challenges, routing protocols in mobile ad hoc networks need to perform better in terms of certain QoS (Quality of Service) parameters such as; good throughput, sustained communication links and least delay in establishing a link. In this paper, we have discussed QoS in MANETs and analyzed the OLSR (Optimized Link State Routing), a well-known routing protocol in MANETs for possible improvements in its performance. Here, we have revised attributes of core parameters of the standard OLSR routing model in order to obtain a new OLSR design. Performances of the standard and revised OLSR models have been tested and compared under different network scenarios using network simulator-3 (NS-3). Different QoS and performance evaluating metrics such as; the throughput, packet delivery ratio, end to end delay, packet loss and normalized routing load have been considered for measuring performances of either OLSR routing models. Based on the analysis, it is concluded that the revised OLSR model has shown better performances as compared to standard OLSR routing model.

Now a day, security in Mobile Ad hoc Network is very important issue. Due to dynamic topology and mobility of nodes, Mobile Ad hoc Networks are more vulnerable to security attacks than conventional wired and wireless network. Nodes of Mobile Ad hoc Network communicate directly without any central base station. That means in ad hoc network, infrastructure is not required for establishing communication. Therefore attacks in this are very frequent than other networks. In this research paper we are describing black hole attacks which are easy to launch in wireless ad hoc network. Black hole attack is referred to as a node dropping all packets and sending forged routing packets to route packets over itself. Ad hoc networks are vulnerable to different kinds of attacks such as: denial of services, impersonation, and eavesdropping.This paper discusses one of the security problems in ad hoc networks called the black hole problem. It occurs when a malicious node referred as black hole joins the network. The black hole conducts its malicious behaviour during the process of route discovery. For any received REQ, the black hole claims having a route and propagates a faked REP. The source node responds to these faked REPs and sends its data through the received routes. Once the data is received by the black hole, it is dropped instead of being sent to the desired destination.The proposed protocol is built on top of the original AODV. It extends the AODV to include the following functionalities: source node waits for a reliable route; each node has a table in which it adds the addresses of the reliable nodes; REP is overloaded with an extra field to indicate the reliability of the replying node.Â

Underwater Acoustic Sensor Networks (UW-ASN) consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area. This paper included a suggestion of using SCTP protocol in place of TCP to minimize many of the problem in transport layer of the sensor network designing part..As well as I have also suggest like an idea to improve the traffic shaping so problem like packet/data loss etc solved and regulate traffic rate is possible so temporary loss of connectivity can be solved. In this paper as possible even I have mention the challenges in various layer of UW-ASN design.