The selective intermediate nodes scheme for ad hoc on-demand routing protocols

In this paper, we consider a mobile ad hoc wireless access network in which mobile nodes can access the Internet via one or more stationary gateway nodes. Mobile nodes outside the transmission range of the gateway can continue to communicate with the gateway via their neighboring nodes over multihop paths. On-demand routing schemes are appealing because of their low routing overhead in bandwidth restricted mobile ad hoc networks, however, their routing control overhead increases exponentially with node density in a given geographic area. To control the overhead of on-demand routing without sacrificing performance, we present a novel extension of the ad hoc on-demand distance vector (AODV) routing protocol, called LB-AODV, which incorporates the concept of load-balancing (LB). Simulation results show that as traffic increases, our proposed LB-AODV routing protocol has a significantly higher packet delivery fraction, a lower end-to-end delay and a reduced routing overhead when compared with both AODV and gossip-based routing protocols.

Multicast routing protocols proposed for mobile ad hoc networks have certain limitations. Most of these protocols try to discover the route on-demand by flooding route request messages, which results in increased end-to-end latency and also consumes considerable amount of network bandwidth. These limitations make protocols not suitable for real-time multimedia communication. In this paper, we have presented an efficient mobile agents aided multicast routing (MAMR) protocol which overcomes these limitations. The protocol is a hybrid protocol where intelligent mobile agents can been integrated with existing on-demand multicast routing protocols such as multicast ad hoc on-demand distance vector (MAODV) routing protocol, on-demand multicast routing protocol (ODMRP) routing protocol and others. Here, the mobile agents move around the network and collect the routing information. This routing information assists on-demand multicast routing protocols in discovering the route in a definite path instead of flooding the route request messages, thereby achieving better end-to-end latency and reduced control traffic in the network. We have used MAODV protocol as an underlying protocol with mobile agents. The proposed MAMR protocol and MAODV have been compared through extensive simulations with end-to-end latency, packet delivery ratio and control overhead as performance parameters

Due to node mobility, the ad hoc network topology is dynamical so that on-demand routing protocols are more fit than other routing protocols. Most secure on-demand routing protocols are designed that the destination or source is able to detect the attacks on routing paths after accepting routing requests or routing replies. In this paper, we present a secure on-demand source routing protocol without the assumption of a specific cryptographic system provides per-hop broadcast authentication in routing discovery phase and security in communication phase and takes effect on our trust-based ad hoc environment. Our hop by hop broadcast authentication provides forwarding routing packets with their trust levels for abstaining from unreliable or malicious nodes. Through security analysis and discussion, we characterize our mechanism and show that it is effectively and efficiently.

Ad Hoc Routing with Distributed Ordered Sequences

We introduce WRP-Lite, which is a table-driven routing protocol that uses non-optimal routes, and compare its performance with the performance of the dynamic source routing (DSR) protocol, which is an on-demand routing protocol for wireless ad-hoc networks. We evaluate the performance of WRP-Lite and DSR for varying degree of mobility and traffic in a 20-node network. The performance parameters are end-to-end delay, control overhead, percentage of packets delivered, and hop distribution. We show that WRP-Lite has much better delay and hop performance while having comparable overhead to DSR.

Mobile adhoc networks (MANETs) consist of mobile nodes with no fixed infrastructure. Dynamic Source Routing (DSR) which is on-demand routing protocol is a widely accepted mobile adhoc network routing protocol used to provide connectivity to mobile nodes. However, DSR and other on-demand routing protocols are vulnerable to different types of security attacks and black hole attack is one of them. In black hole attack, malicious node sends a fake route reply in response of route request to source node claiming for an optimal route to the destination. Thus, node which starts route discovery process establishes a path through malicious node and starts sending data packet on this route. Malicious node drops the data packet which reduces packet delivery ratio. To secure DSR, we propose a scheme which confirms the authenticity of route with the help of verification packet. This packet is generated by first intermediate hop in the route of route reply. Simulation results show improvement in packet delivery ratio and throughput.

Mobile Ad Hoc Networks (MANETs) are decentralized, infrastructure-less wireless systems that rely heavily on efficient routing protocols due to their dynamic and resource-constrained nature. Dynamic Source Routing (DSR) is widely adopted for such environments; however, it suffers from notable limitations, including cache saturation, memory inefficiencies, and lack of link quality awareness. These weaknesses reduce performance in high-mobility or large-scale scenarios and limit the reliability of DSR in real-world applications like military or disaster recovery networks. Motivated by these challenges, this paper proposes a comprehensive enhancement to DSR through intelligent caching strategies to improve scalability, energy efficiency, and route reliability. The proposed model introduces a dynamic route compression technique that reduces route size by eliminating redundant intermediate nodes. It also incorporates a hierarchical caching scheme where clusters managed by energy-aware Cluster Heads (CHs) distribute cache responsibilities, thereby improving scalability and reducing overhead. In addition, link quality metrics such as residual energy and link duration are integrated into route selection, enabling more stable and energy-efficient communication paths. Simulations using NS-2 across varying network sizes (50, 75, 100 nodes) revealed that the enhanced DSR significantly improves key performance metrics such as Packet Delivery Ratio (PDR), routing overhead, cache hit rate, and energy consumption. Route compression alone yielded a 14.3 PDR improvement and 21% reduction in overhead, while the hierarchical approach further optimized network performance. These results confirm the feasibility and effectiveness of the proposed enhancements, addressing longstanding gaps in traditional DSR implementations and laying a foundation for scalable and intelligent MANET routing protocols.

The virtual backbone is an approach for solving routing problems in ad-hoc wireless networks. The virtual backbone approach features low latency, moderate routing overhead and is a hybrid scheme that uses the table-driven and on-demand routing protocols. This work presents a distributed virtual backbone development scheme for ad-hoc wireless networks. Using clustering, distributed labeling and heuristic Steiner tree techniques, our scheme outperforms other schemes in terms of the size and stability of the virtual backbone and the virtual backbone change rate. Experimental results demonstrate that our scheme has lower overhead than traditional table-driven and on-demand routing schemes.

An optimized node-disjoint multipath routing scheme in mobile ad hoc

In recent years, there have been significant efforts related to vehicle-to-vehicle (V2V) communication. The major demand of the V2V communication was originally from safety-related applications; and the possible application areas including communication support for auto-navigation have increased. Local Peer Group (LPG) is a partitioning structure to promote quick deliveries of time- sensitive information and efficient use of wireless media. LPG organizes vehicles into manageable vehicle groups prior to a need for delivering relevant emergency messages, and provides efficient data dissemination (both multicast and unicast) among vehicles. In this paper, we first provide an overview of LPG structure and proactive unicast inside LPG. As the focus of this paper, we then present a new on-demand unicast routing protocol that supports inter-LPG communications - with aspects of route search, establishment and maintenance. Our preliminary simulation results indicate that our proposed inter-LPG unicast routing protocol has control overhead that is significantly lower than the conventional on-demand routing protocols.

Mobile ad-hoc network and its several aspects are gaining popularity day-by-day in the research field as new technology is emerging in its way to renovate the field as a companion of wireless sensor networks. While working on several routing protocols of mobile ad-hoc network I became familiar with two prominent on-demand routing protocols for mobile ad hoc networks - Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV). Both DSR and AODV share the similar on-demand behavior, in spite of their different mechanism of finding next route to the destination. AODV protocol is the main concern for performance evaluation in the hostile network as it is the most efficient dynamic, that is, on demand routing algorithm. In this paper, I elaborately evaluate the performance of AODV routing protocol in the hostile environment which may be intentional or unintentional hostility. These types of unfriendly attitude of the mobile environment ultimately deteriorates the performance of the network for which I designed an efficient pruning mechanism based on limited broadcasting techniques for the AODV protocol which performs well with minimum latency, minimum end-to-end delay of data packets and maximum packet delivery fraction.

Dynamic Source Routing (DSR) [1,2], which is an on-demand routing protocol, becomes the most popular source routing protocol for MANET. Each mobile node is required to maintain route caches that contain the source routes of which the mobile is aware. Although DSR can respond a route quickly, it yields a long delay when a route is rebuilt. This is because when source node receives RERR packet, it will try to find alternative routes from route cache. If alternative routes are not available, source node, then, will enter route discovery phase to find new routes. Finding a route in wireless network require considerable resources, such as time, bandwidth, and power because it relies on broadcasting. As the extension of DISTANCE algorithm presented in [3], Adaptive DISTANCE (ADISTANCE) is proposed in this paper. From simulation result it shows that the adaptive extension of DISTANCE gives ability to work in asynchronous communication network.

With on-demand routing protocols for mobile ad hoc networks (MANETs), for example, dynamic source routing (DSR), a source node tries to find a route to the destination node only when it has a packet addressed to that destination node. And the source node can find a route either from its own route cache or by initializing a route discovery. To reduce the traffic generated by such route discoveries, caching of routing information is necessary. And in the design of caching schemes, cache timeout (i.e., the time period that a link would stay in the cache) is a critical parameter. However, only a few works have been done on how to set it. In this paper, we propose a new link caching scheme with adaptive timeouts. In this scheme, the cache timeout of a link is decided based on the estimation of the link's lifetime. Simulation results show that the proposed scheme can adapt to scenario changes and hence improve the performance of on-demand routing for MANETs.

In many traditional hierarchical routing protocols proposed for mobile ad hoc networks, each cluster designates a single cluster-head (CH) node to relay inter-cluster traffic. These cluster-head nodes become traffic “hot-spots” and restricting cluster to access through cluster-head nodes can lead to sub-optimal route. To solve these problems, we proposed a novel cluster-based distributed gateways routing protocol, namely DGR. In our proposed scheme, we rely on border mobile terminals (BMTs) as gateways for inter-cluster routing instead of relying on CHs. CHs are not necessarily involved in each route search and data transmission process. In addition, we also proposed a cluster reformation criterion to avoid unnecessary cluster reformation. It is proved that the proposed scheme can reduce the route search time, alleviate the burden of CHs and achieve optimal routes. Moreover, it can make clusters much more stable for nodes mobility under the proposed cluster reformation criteria.

A mobile ad hoc network is a network of mobile nodes connected by multi-hop wireless links without centralized infrastructure support. The area of ad hoc networking is receiving increasing attention in recent years. Efficient dynamic routing is an important research challenge in such a network. In recent years, routing has been the most focused area in ad hoc networks research. On-demand routing, in particular, is widely developed in bandwidth constrained mobile wireless ad hoc networks because of its effectiveness and efficiency. A variety of new multipath routing protocols targeted at the ad hoc networking environment have been proposed. Multipath routing improves the throughput of ad hoc networks; it is a straightforward mechanism to recover from route losses in a dynamic network. In this paper we have considered a very well-known multipath routing protocol called ad hoc on-demand multipath distance vector routing (AOMDV) on both MAC layers, the standard IEEE 802.11 and a TDMA MAC protocol called evolutionary-TDMA (E-TDMA). We have evaluated the performance of these multipath routing through simulations using NS2 varying the number of paths (particularly we have considered 2 and 3 paths) and varying the number of temporary colors.