An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. In this paper we present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each Mobile Host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic selfstarting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance-vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.

Mobile ad hoc networks (MANETs) consist of a set of similar mobile nodes, communicating with each other using wireless links. As a node may not be able to directly reach every other node, a packet may need to traverse multiple wireless links from its source to its destination. Unidirectional links can occur in such networks. Several existing routing protocols implicitly assume bidirectional links when making their routing decisions. Not using unidirectional links can lead to sub-optimal routes. A tunneling solution to allow efficient operation in ad hoc networks with unidirectional links is presented. The tunneling solution uses information gathered by the routing protocol to tunnel packets from the end-point of the unidirectional link to its source. A naive implementation of tunneling could lead to loops in the system and a deluge of packets. This is because when ACKs for link layer messages are tunneled across unidirectional links, ACKs for them may end up being generated recursively. The solution presented here prevents such a packet explosion from occurring.

Abstract. In this paper, a new hierarchical multihop routing algorithm and its performance evaluation is presented for fully dynamic wireless networks. The routing algorithm operates on a virtual topology obtained by partitioning the routing information for mobile terminals and mobile base stations into a hierarchical, distributed database. Based on the virtual topology, each mobile base station stores a fraction of the routing information to balance the complexity of the location-update and the path-finding operations. Mobility of the network entities changes the load distribution and causes processing and memory bottlenecks in some parts of the network. However, since the network routing elements are also mobile, their movement can be used to distribute the load. Thus, new load balancing schemes are intoduced to distribute the routing overhead uniformly among the mobile base stations. The performance of the hierarchical multihop routing algorithm is investigated through simulations. It is shown that the routing protocol can cope with high mobility and deliver packets to the destinations successfully.

To ease the development for sensor networks, we propose a two-stage top-down flow: design and simulation, then synthesis of sensor code. The flow is an alternative to a direct design at node level. The first operation is to describe network topologies on a graph model using textual or interactive tools. Simulations are achieved by generating a system of processes into an Occam program which is compiled and executed. This program represents a distributed machine conforming to the synchronous communication model, which is a strong reference for algorithm design. The network simulation allows an early check of solutions to problems such as routing or dumping network data in various deployment topologies. It provides fast exploration of algorithm, and topology spaces, focusing on the difficult collective behaviour rather than local level programming. 1.

A Mobile Ad-Hoc Network (MANET) in which mobile nodes can access the Internet via a stationary gateway node or access point. Ad-Hoc On Demand Distance Vector Routing (AODV) protocol has been studied to provide the connectivity to the wired network (internet and other resources) via gateway. An Attempt has been made to enable Mobile nodes to always have the fresher routes to the Gateway. All the traffic from the mobile node to the wired network will pass through the Gateway which understands the protocol of both wired networks and Mobile Ad-Hoc network. Three different approaches have been proposed to update the information with the mobile nodes about the wired Gateways. This Performance analysis has been done in a simulation environment. For the simulation purpose we have used the Network Simulator (NS-2), a widely available simulation tool.