Towards a Novel Transport Protocol for Ad Hoc Networks

Broadcasting is an indispensable operation for multi-hop mobile ad hoc network (MANET) to provide control or routing functionalities. In MANET, since a packet relayed by any node can reach all its neighbour nodes, broadcasting by flooding is inefficient and results in many redundant relays. In this paper, we analyze the deficiencies of some previous broadcasting protocols and propose two enhanced lightweight protocols, namely hop count-aided broadcasting (HCAB) and self-adaptive probability broadcasting (SAPB). The proposed protocols can reduce broadcasting redundancy significantly and guarantee high broadcasting coverage as well. More importantly, the proposed protocols are lightweight, which means each node makes relay decision without any knowledge of its neighbours. Thus, the proposed protocols have low overhead and are attractive to capacity limited mobile devices. Simulation results show that the proposed protocols eliminate unnecessary relay efficiently and outperform the existing lightweight broadcasting protocols

Evolutionary algorithms are metaheuristic algorithms that provide quasioptimal solutions in a reasonable time. They have been applied to many optimization problems in a high number of scientific areas. In this survey paper, we focus on the application of evolutionary algorithms to solve optimization problems related to a type of complex network like mobile multihop ad hoc networks. Since its origin, mobile multihop ad hoc network has evolved causing new types of multihop networks to appear such as vehicular ad hoc networks and delay tolerant networks, leading to the solution of new issues and optimization problems. In this survey, we review the main work presented for each type of mobile multihop ad hoc network and we also present some innovative ideas and open challenges to guide further research in this topic.

Many previous papers have pointed out that TCP performance in multi-hop ad hoc networks is not optimal. This is due to several TCP design principles that reflect the characteristics of wired networks dominant at the time when TCP was designed, but are not adequate for multi-hop ad hoc networks. For example, congestion phenomena in multi-hop networks are very different than in traditional wired networks, and route failures and route changes may be frequent events. To overcome these problems, in a previous work we presented a novel transport protocol - named TPA - specifically tailored to multi-hop ad hoc networks. In this paper we perform an experimental analysis of TPA in static multi-hop scenarios. Specifically, we compare TPA and TCP performance in a chain topology with different number of hops and traffic patterns. We also consider the effect of the routing protocol. Our experimental results show that TPA protocol outperforms TCP significantly both in terms of throughput and energy consumption

Reputed Packet Delivery Using Efficient Audit Misbehaviour Detection and Monitoring Method in Mobile Ad Hoc Networks

In this paper, a new cross layer design of MAC and Routing protocol for OFDMA-based Multi-hop Ad-hoc Networks is proposed. In wireless network, when a route is established, the radio resource allocation problems at MAC layer may decrease the end to end performance proportionally with the length of each route. The contention at MAC layer may causes routing protocol to respond by finding new routes and routing table updates. The cross layer design allows layers to exchange state information in order to solve the problem and obtain higher performance. The proposed cross layer design of MAC and Routing protocol based the dynamic Sub-channel Assignment Algorithm in [4] to ensure the performance of ad-hoc and multi-hop networks is significantly improved.

The Transmission Control Protocol (TCP) is by far the most dominant transport protocol in the Internet and is the protocol of choice for most network applications. The focus of this chapter is to present approaches for ad-hoc networks that provide the same end-to-end semantics as TCP. In this regard, we first investigate the different problems experienced by TCP in ad-hoc networks, and provide insights into how the different design components of TCP relate to the characteristics of such networks. We then identify three major classes of approaches to improve the transport layer performance in ad-hoc networks. We present a protocol instance for each of the three approaches in detail and highlight the specific problems it addresses. We also discuss the trade-offs stemming from the adoption of each of the protocols considered.

This paper proposes a mathematical framework to model and analyze the energy consumption of routing protocols in multihop wireless networks such Mobile Ad Hoc Networks (MANETs) or Sensor Networks (WSNs) by taking into account the protocol parameters, the traffic pattern and the network characteristics defined by the medium channel properties, the dynamic topology behavior, the network diameter and the nodes density. Moreover, our framework allows to classify routing protocols by exploring the relationship between application requirements and wireless network features. To the best of our knowledge, there is no such proposed framework that provides in-depth an analytical investigation of above relationship. We apply this model to a Beacon-less routing protocol Pizza-Forwarding (PF) compared to well known routing protocols such as Optimized Link State Routing, Ad Hoc On Demand Distance Vector Routing, Greedy Perimeter Stateless Routing and a Simple Random Walk Routing in order to underline their behavior according to the network features and application requirements. Finally, we show that Beacon-less routing protocol should be a best candidate to save energy in WSNs.

Recent demands on affordable, portable wireless communication and computation devices have resulted in exponential growth of wireless networks ranging from Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWAN) to Ad-Hoc and Sensor networks. The major goal of wireless communication is to allow users to communicate together and to have access to global network anytime anywhere. This has led to wide acceptance of infrastructure based cellular networks (WWANs) where mobile stations communicate with a centralized controller, often referred as Access Point (AP) that is connected to the wired networks. On the other hand, WLANs have appeared as dominant popular technologies in many venues including a local area such as an academic campus or an airport terminal. These wireless networks mostly rely on IEEE 802.11 Wi-Fi (Wireless Fidelity) technology and its various derived versions (i.e. 802.11a,b,g). IEEE 802.11 standard supports two operational modes: The infrastructure-based Wireless Local Area Networks (WLANs) and an infrastructure-less Ad-Hoc Networks. A WLAN (Conti, 2003) typically imposes the existence of an AP and normally is connected to the wired networks to provide internet access for mobile devices. Obviously, only one hop link is needed to communicate between mobile devices and AP. In contrast, there is no AP or infrastructure in Ad-Hoc networks. Any two stations can communicate directly when they are in the range of reception of each other. To this end, the stations may use multi-hop routing to deliver their packets to destinations. The ad-hoc protocols (Conti, 2003; Mohapatra & Krishnamurthy, 2005) are self-configured for address and routing in the face of mobility and the network topology may change in each configuration. The multi-hop wireless ad-hoc networks, or multi-hop wireless networks enable wireless networking in the environments where the wired or cellular connections are impossible, inadequate, or cost effective (e.g. battle field, disaster recovery, etc.). The popularity of internet over the last decades has resulted in rapid advancement of demanding applications. The Transmission Control Protocol/Internet Protocol (TCP/IP) (Stevens, 1994) is a well-known de facto protocol in developing today’s internet. Basically, TCP provides a connection-oriented and reliable end-to-end data delivery between two hosts in traditional wired networks. Since TCP is well tuned and due to its wide acceptance in internet, it is desirable to extend and adopt its functionality to wireless networks. On the

TDMA-based Medium Access Control (MAC) protocols for ad hoc networks achieve good performances at high loads and high network densities. Nevertheless, their slot assignment techniques infer inefficient and unfair resources exploitation due to free slots appearance and slot assignment regardless the effective needs. This paper tackles these disadvantages by performing a slot-by-slot reservation mechanism. It results a new MAC protocol, called OSTR (One shot Slot TDMA-based Reservation). OSTR operates in a distributed and slotted environment. It is a topology-based and dynamic frame size-based protocol. OSTR leads to a slower frame size increase. Experimental results show that OSTR achieves a shorter frame size even with high densities inferring a better channel utilization.

A packet control mechanism via a cross-layer feedback to reduce bursts of packet drops for transmission of video over mobile multihop ad-hoc networks is presented. With this approach, the application layer would be capable of controlling the packet transmission flow in accordance with the multihop characteristics of the routing layer.

Ad-hoc networks are completely wireless networks of mobile hosts, in which the topology rapidly changes due to the movement of mobile hosts. This frequent topology may lead to sudden packet losses and delays. Transport protocols like TCP have been built mainly for reliable, fixed networks. Hence, when used in ad-hoc networks, TCP misinterprets this loss as congestion and invokes congestion control. This leads to unnecessary retransmissions and loss of throughput. To overcome this problem, a feedback scheme is proposed, so that the source can distinguish between route failure and network congestion. When a route is disrupted, the source is sent a route failure notification (RFN) packet, allowing it to freeze its timers and stop sending packets. When the route is re-established, the source is informed through a route re-establishment notification (RRN) packet, upon which it resumes by unfreezing timers and continuing packet transmissions. The simulated performance of TCP on ad-hoc networks with and without feedback is compared and reported. It is observed that in the event of route failures, as the route re-establishment time increases, the use of feedback provides significant gains in throughput as well as savings in unnecessary packet transmissions. Several further enhancements and directions for future work are also sketched.

Ad hoc networks are useful in many application areas. Security is important but it is a challenging issue due to ad hoc network’s characteristics such as lack of infrastructure, communication over wireless medium, and node mobility. In this paper we present a secure multicast routing protocol for ad hoc networks. The proposed protocol makes it possible for a node to create a new multicast group and join or leave an existing group securely. It also includes a mechanism for detecting and repairing broken links securely. In addition to securely exchanging multicast packets, this paper addresses the problem of securely building and maintaining multicast trees in ad hoc networks. Moreover, the protocol guards against attacks from authorized but misbehaving nodes as well as unauthorized nodes.

Trust and reputation systems play an important role in collaborative operations in mobile ad hoc networks. However, the security of trust and reputation system itself is threatened by the existence of selfish nodes. Selfish nodes can make passive attacks on the foundational process of trust and reputation system, the recommendation acquisition, through non cooperation of packet forwarding and recommendation rendering. Existing trust and reputation systems commonly suffer from vulnerability caused by the failure of recommendation acquisition which refers to the unsuccessful recommendation information obtaining from one node to another node. A credit-based mechanism is proposed to address this problem by offering credits as incentives to both intermediate nodes and recommendation render nodes. Furthermore, competition between selfish nodes is explored to prevent selfish nodes being paid excessive credits. Simulation results show that the proposed mechanism can effectively improve the success rate of recommendation acquisition and lower the total paid payoffs.

Owing to the absence of any static support structure, ad-hoc networks are prone to link failures. The 'shortest path seeking' routing protocols may not lead to stable routes. The consequent route failures that ensue, lead to the degradation of system throughput. This paper suggests a routing protocol wherein the route selection is done on the basis of an intelligent residual lifetime assessment of the candidate routes. Schemes for performance enhancement with TCP and non-TCP traffic in ad-hoc networks are proposed. The protocol is backed by simulations in ns that show excellent adaptation to increasing network mobility. We have also introduced new route cache management and power aware data transmission schemes.

Mobile Ad-hoc Network (MANET) has emerged as the self organized wire less interconnection for the various applications in random topology. As most of the multimedia applications require strict QoS guarantee during the communication between a single source and multiple destinations. How ever, achieving reliable multicast transmission in MANET is crucial due to the dynamic network topology caused by the node mobility. This gives rise to the need for an efficient multicast routing strategy. This paper proposes a novel scheme PBMRP-BR (position-based Multicast Routing Protocol for Ad-hoc Network Using Backpressure Restoration) for efficient transmission of multimedia applications in Ad-hoc Network, which provides priorities for routing based on Distance of path, Load at the node (ie, traffic) and queue length at the node(ie, bandwidth). It also keeps the path information including bandwidth resources of each node for routing decisions. The problem of the link failure in the channel during the call in progress thus lead in the degradation of the QoS (Quality of Service).To deal this we are using a Backpressure Technique The simulation results shows that the proposed algorithm is able to find a better solution, fast convergence speed and high reliability. The simulation results shows the proposed PBMRP-BR protocol achieve the above objectives and gives the batter results than previous schemes like DSR for the maintenance of overheads and the path reliability. Our proposed scheme will improve the bandwidth utilization by reducing the congestion in the Adhoc wireless network.