A Mobile Ad hoc Network (MANET) is a collection of autonomous self-organized nodes. They use wireless mediu m for co mmunicat ion, thus two nodes can communicate directly if and only if they are within each other"s transmission radius in a mu lti-hop fashion. Many conventional routing algorithms have been proposed for MANETs. An emerg ing area that has recently captured much attention in network routing researches is Swarm Intelligence (SI). Besides conventional approaches, many new researches have proposed the adoption of Swarm Intelligence for MANET routing. Swarm Intelligence (SI) refers to complex behaviors that arise fro m very simp le individual behaviors and interactions, which is often observed in nature, especially among social insects such as ants, bees, fishes etc. Although each individual has little intelligence and simp ly follows basic rules using local in formation obtained fro m the environ ment. Ants routing resembles basic mechanisms fro m distributed Swarm Intelligence (SI) in b iological systems and turns out to become an interesting solution where routing is a problem. Ants based routing is gaining more popularity because of its adaptive and dynamic nature. A nu mber of Swarm Intelligence (SI) based algorithms were p roposed by researchers. In this paper, we study bio-inspired routing protocols for MANETs.

Mobile Ad hoc Network (MANET) is an autonomous collection of mobile nodes that form a temporary network without of any existing network infrastructure or central access point. The popularity of these networks created security challenges as an important issue. The traditional routing protocols perform well with dynamically changing topology but are not designed to defense against security challenges. In this paper we discuss about current challenges in an ad hoc environment which includes the different types of potential attacks that are possible in the Mobile Ad hoc Networks that can harm its working and operation. We have done literature study and gathered information relating to various types of attacks. In our study, we have found that there is no general algorithm that suits well against the most commonly known attacks. But the complete security solution requires the prevention, detection and reaction mechanisms applied in MANET. To develop suitable security solutions for such environments, we must first understand how MANETs can be attacked. This paper provides a comprehensive study of attacks against mobile ad hoc networks. We present a detailed classification of the attacks against MANETs

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Wireless networks, in particular Mobile Ad hoc Networks (MANETs) have revolutionized the field of networking with increasing number of their commercial and military applications. Security on the other hand, is now an essential requirement for these applications. However, the limitations of the dynamic, infrastructure-less nature of MANETs impose major difficulties in establishing a secure framework suitable for such services. Security for MANETs is a dynamic area of research. Most of the traditional routing protocols proposed for MANETs are focused on routing only not on the security aspects. As in traditional wired networks, wireless networks also require security. Unlike the wired networks, where dedicated routers, servers control the network, in MANETs nodes act both as terminals and also as routers for other nodes. A popular mechanism to satisfy the security requirements is the Group Key Management in which the group key is to be shared by each group communication participant. But to establish and manage the group key efficiently imposes new challengesespecially in infrastructure less MANETs. The basic needs of such networks require that the group key schemes must demonstrate not only high performance but also fault-tolerance.

In this paper, we develop a two node tandem communication network model with dynamic bandwidth allocation and feedback for the first node. In most of the communication systems, the arrivals of packets follow Non-Homogeneous and arrival rate is time dependent. In this model, the transmission rate of each transmitter depends on the number of packets in the buffer connected it. The transmission rates at each transmitter are adjusted depending upon the content of the buffer connected to it. The packets transmitted through the first transmitter may be forwarded to the buffer connected to the second transmitter or returned back to the first buffer with certain probabilities. Using the difference-differential equations the performance measures including average number of packets in each buffer, the probability of emptiness of the network, the average waiting time in the buffer and in the network, the throughput of the transmitters, and the variance of the number of packets in the buffer are calculated. It is observed that the load dependent transmission can reduce the delays in the transmission and enhance the channel capacity.