Agent based Congestion Control Performance in Mobile ad-hoc Network:A Survey paper

In today's world mobile agents and mobile ad- hoc networks are the two technologies that are contributing towards better connectivity and communicability. When the two technologies used jointly, the interest is increased. Due to the properties like self- configuration and infrastructure-less, the mobile ad-hoc networks provide various remarkable features. But the various challenges are also associated with mobile ad-hoc networks like dynamic topology, mobility, energy constraint etc. Mobile agent provides solution to these challenges. A mobile agent is a new way of computer interactions and provides better options for the developers to create applications based on connectivity. Mobile agents move around the ad-hoc networks in a different and better way than the other widespread client server architecture based applications. Due to their mobility and autonomy these agents can perform various functions in mobile ad-hoc networks like topology discovery, routing, key management, congestion control etc. The paper reviews the role of the mobile agents in the mobile ad-hoc networks, and emphasizes its application on the various layers of a layered architecture of mobile ad-hoc networks and concludes its merits as compared to other conventional approaches.

A mobile ad-hoc network (MANET) is a special type of wireless networks. It consists of a collection of mobile nodes that are capable of communicating with each other without help from a fixed infrastructure. The interconnections between nodes are capable of changing on a continual and arbitrary basis. Nodes within each other's radio range communicate directly via wireless links, while those that are far apart use other nodes as relays in a multi-hop routing fashion. The typical applications of MANETs include conferences or meetings, emergency operations such as disaster rescue, and battlefield communications. Transmission Control Protocol (TCP) [1] is a reliable, connection-oriented, full-duplex, transport protocol widely used in wired networks. TCP’s flow and congestion control mechanisms are based upon the assumption that packet loss is an indication of congestion. While this assumption holds in wired networks, it does not hold in the case of mobile wireless networks. In addition to congestion, a transport protocol in an ad hoc network must handle mobilityinduced disconnection and reconnection, route change-induced packet out-of-order delivery for mobile hosts, and error/contention prone wireless transmissions. Reaction to these events might require transport control actions different from congestion control. It might be better to periodically probe the network during disconnection than to back off exponentially [2], and it makes more sense simply to re-transmit a packet lost to random channel error than to multiplicatively decrease the current congestion window [3]. Even if the correct action is executed in response to each type of network event, it is not immediately obvious how to construct an engine that will accurately detect and classify events. Packet loss alone cannot detect and differentiate all these new network events [4]. In this paper, we first describe the necessary network states in an ad hoc network to be identified by TCP and use an end-to-end approach for identification of congestion state in ad hoc network then examine metrics that can be measured end-to-end. Two metrics are devised to detect congestion, IDD (Inter Delay Difference) and STT (Short Term Throughput).The approach we propose in this paper utilizes network layer feedback (from intermediate hops) for identification of disconnection state to put TCP sender into persist mode. Therefore we use from advantage of both end to end measurements and network layer feedback. The remainder of the chapter is organized as follows: It starts with describing TCP’s challenges in MANETs environment in Section 2. Section 3 provides an overview of related

A mobile agent based congestion control AODV routing protocol is proposed to avoid congestion in ad hoc network. Some mobile agents are added in ad hoc network, which carry routing information and nodes congestion status. When mobile agent travels through the network, it can select a less-loaded neighbor node as its next hop and update the routing table according to the node's congestion status. With the aid of mobile agents, the nodes can get the dynamic network topology in time. Simulation indicates that this new protocol balances the traffic load, prolongs the lifetime of network, and reduces the end-to-end delay.

In Mobile Ad hoc Networks (MANETs) obstruction occurs due to the packet failure and it can be successfully reduced by involving congestion control scheme which includes routing algorithm and a flow control at the network layer. In this paper, we propose to framework and implimentationan agent based congestion control technique for MANETs. In our technique, the information about network obstruction is collected and disseminated by mobile agents (MA). The nodes are classified into four categories based on its traffic class. The MA measures the get in line length of the various traffic classes and the channel disagreement and estimates the total congestion metric to find the minimum congestion level in the network. The congestion metric is applied in the routing protocol to select the minimum congested route. By simulation results, we show that our proposed technique attains high delivery ratio and throughput with reduced delay when compared with the presented technique.KeywordsMobile Ad hoc Networks (MANETs)mobile agents (MA)TCPEDCA Mechanism of 802.11eCBRFTPMAC Layer

The (MANET) ad-hoc mobile network is an automated, network in which android systems link to wireless devices. Ad hoc word means "for this purpose". In MANET any device can easily move in various directions. MANETs (Mobile Ad Hoc Networks) are the basics of broadband networks. In MANET network user can link and get connected anywhere, anytime through communication. MANET introduces a new co system for communication. MANET does not require a fixed structure relies on unconnected ports for service transportation delivery. The temporary hoc network is not dependent on mobile devices (android phones, laptop, PCs, sensors, etc.) that connect exclusively to wireless connectors. Ad-hoc work on a distributed system to provide the required network performance when there is no fixed structure. In this network, it acts as a standalone network or with many attachment points on mobile networks. This paper provides view on the features, applications of ad hoc networks, characteristics and various attacks and challenges faced by programmers and Users . We analyze MANET security objectives and will outline the features, structure, types and challenges of research and the latest trend analysis presented on Mobile Ad Hoc Network to explore open-ended issues in developing navigation strategies for MANET.

Mobile Ad-hoc Networks (MANETs) is one kind of wireless mobile network. It helps to communicate between the mobile nodes (devices) any time and in any location. MANETs can change the locations and has the ability to discover the path dynamically. In other words, topology is updated rapidly due to the dynamic nature of the nodes. There are many issues associated with MANETs such as fading, multiuser interference, frequent topology change, optimum routing, etc., that affect the efficient data transfer. This paper proactively selects best optimum path among the multiple paths. Ultimately, the outcomes of the proposed technique, REHDIS increases the speed of data transfer, reduces the End-to-End delay, produces less Packet Drop and increases Packet Delivery Ratio. REHDIS has been evaluated using Network Simulator — 2.34(NS-2.34).

Power control algorithms for mobile ad hoc networks

User Datagram Protocol (UDP) is proposed for the efficient servicing of multimedia traffic flows in Internet and it does not make use of any congestion control mechanism. The Internet Engineering Task Force (IETF) is working on development of a protocol standard that is suited to the needs of multimedia applications, known as the Datagram Congestion Control Protocol (DCCP) [6]. DCCP combines the end-to-end transport and congestion control semantics of TCP with the low-delay unreliable service provided by UDP. DCCP performance over the wired network with bursty traffic has been tested and has shown that DCCP holds promise as a wired network transport protocol [4]. However, to the best of our knowledge, the working of DCCP over Mobile Ad hoc Networks has not been evaluated. In this paper, we have evaluated the performance of DCCP over Mobile Ad Hoc Networks [10]. The two congestion control schemes made available under DCCP (TCP-like - CCID2 and TFRC - CCID3) were evaluated in a simulation environment, comparing with TCP considering throughput, end-to-end delay and packet loss as metrics [7,8]. Our results show that DCCP achieves considerably better throughput than TCP.

Service discovery is an integral part of Mobile Ad Hoc Networks (MANETs). While several service discovery protocols such as Service Location Protocol [1] and Universal Plug and Play (UPnP)[2] have been developed, most of them are designed for infrastructure based networks and thus not suitable to be used in MANETs. This paper proposes Mobile Agent Based Service Discovery (MASD) for Ad Hoc network. It is a policy driven agent based mechanism that facilitates cross platform service discovery in ad-hoc environments. The various agents are chosen in MASD which executes the predefined policies. Our approach achieves a high degree of flexibility in adapting itself to changes in ad-hoc environments and is aware of common problems associated with structured compound formation in mobile Ad Hoc environments. Mechanism consists of grouping mobile nodes into clusters while a gateway in each cluster is responsible for routing. We evaluated the performance of the scheme by running simulations on Glomosim simulator. Also the motion of agents is taken care of by PMADE (Platform for Mobile Agent Distribution and Execution).The results obtained shows that MASD is quite effective for successful service discovery in MANETs.

Mobile ad-hoc networks are a type of self-configuring networks in which the node moves from one location to another without any fixed infrastructure. Providing security in mobile ad-hoc networks is a challenging task due to its frequent topology change. Protecting legitimate nodes from the malevolent nodes is an important factor. To solve this problem, we propose trusted agent-based lightweight surprise check for malevolent node detection in mobile ad-hoc networks. This scheme uses three phases: lightweight surprise check manager, cluster formation and mobile agent phase. Lightweight surprise check manager detects the malevolent node based on node forward rate, node acknowledgement, secure communication and node location. In cluster phase, the clusters are formed depending upon received signal strength and the cluster heads are elected based on the residual energy and utility of neighbors. In mobile agent phase, the secret key method is used to verify the mobile agent authentication. The mobile agent is used for data communication among cluster head to destination, thus it reduces the energy utilization, network overload, average delay as well as improve the network efficiency in the network. Simulation results shows that the lightweight surprise check scheme provides improved security and quality of service compared to the existing schemes.

Mobility modelling plays a pivotal role in evaluating the performance of Mobile Ad Hoc Networks (MANETs), as the movement patterns of nodes strongly influence routing efficiency, connectivity, and network stability. Existing mobility models, particularly entity and group-based frameworks, have proven useful in simulating various MANET applications but remain limited in capturing the complex movement behaviour characteristic of Search-and-Rescue (SAR) operations in disaster scenarios. This study proposes a realistic hybrid mobility model that integrates the essential features of both entity and group mobility paradigms to better represent the coordinated yet flexible dynamics of SAR teams. Three sets of simulations were performed using the Network Simulator 2 (NS2). The first and second simulations focused on generating and combining existing entity and group mobility patterns using the BonnMotion tool, resulting in two composite models (Real1 and Real2). The third simulation compared these models using AODV and DSDV routing protocols under varying node mobility levels and traffic conditions. Key performance metrics, including relative mobility, node degree, partition count, link duration, packet delivery ratio (PDR), throughput, and average end-to-end delay, were analysed. Results demonstrate that it is feasible to concatenate existing mobility models into a coherent hybrid framework. Among the developed models, Real2 exhibited superior performance in most test conditions, yielding higher PDR, lower delay, and more stable connectivity than its constituent models. These findings confirm that the performance of MANETs is highly dependent on mobility realism. Consequently, selecting a model that accurately reflects the behavioural characteristics of the target scenario is essential for credible MANET performance evaluation in emergency response contexts.

Broadcasting is the most common operation of data transmission in mobile Ad Hoc networks. The conventional blind flooding algorithm incurs the broadcast storm problem. Moreover, energy is critical for the life and the performance of Ad Hoc networks. In order to alleviate the broadcast storm, balance the node energy in network and provide broadcast reliability, a reliable broadcasting algorithm based on the distance and the energy balance is proposed in this paper. In this algorithm, a node determines the distance to the immediate previous neighbor node by obtaining the information of neighbor node from the received data packets. Then a node will schedule the forwarding in a time-division manner according to its forwarding priority which is determined by the distance to the immediate previous node and its own residual energy. To provide reliable broadcast, the algorithm also adopts retransmission mechanism utilizing broadcast packets to acknowledge those packets correctly received instead of acknowledgement packets such as ACK. Simulation results show that this algorithm achieves high arrival rate and lower latency. Meanwhile, it can balance energy consumption of the nodes in a network and prolong the network lifetime.

An ad-hoc Wireless Local Area Network (WLAN) is a network without infrastructure connectivity where different types of hosts (nodes) exist; such as PDAs (personal digital assistants), laptops and cellular phones. These nodes are equipped with short range transmitters and receivers, and antennas which may be Omni directional (broadcast), highly directional (Point-to-point), or a combination of the two. A Mobile Ad hoc Network (MANET) is a collection of mobile hosts that move in different directions and speeds without the need to maintain connectivity with existing network infrastructure. Different routing protocols have been designed since the existence of ad hoc networks. This work presented below proposes a new routing protocol for ad hoc networks which aims to reduce network overhead, power consumption, Multi-user Interference (MUI), and provide link reliability. In recent years, a vast research has been seen going on in the field of Mobile Ad Hoc Networks (MANETs). Due to limited resources in MANETs, to design an efficient and reliable routing strategy is still a challenge. An intelligent routing strategy is required to efficiently use the limited resources. Also the algorithms designed for traditional wired networks such as link-state or distance vector, does not scale well in wireless environment

There have been many studies in recent years reporting the performance and survivability of mobile ad-hoc networks (MANETs). These studies invariably consider the network as covering a relatively small geographic area. However, in many crises, such as may occur during disaster relief and military operations, a wide geographic area may require network coverage. In these circumstances, the infrastructure free mobile wireless communications features of MANETs may be critical in forming a satisfactory network. Given transmission range limitations within current MANET proposals, it is likely that providing network coverage to a wide geographic area would be problematic. This paper presents the results of a study on clustering in the spatial distribution of communication nodes. A realistic environment (e.g. topography and organisational limitations) and operating procedures are introduced through the use of the results of war games. The spatial distribution of nodes is used as the basis for MANET internetwork topology generation.

Mobile Ad-Hoc Networks (MANETs) provides substantial services in the field of network. MANETs is an infrastructure-less network, containing more number of individual wireless mobile nodes (devices) that communicate with one another without any aid of centralized server or base station. Due to dynamic topology, MANETs faces many issues associated with mobile nodes such as link failure, battery power, delay, etc. The main aim of this paper is to reduce data transfer delay by finding optimum path. Ultimately, the outcomes of the proposed work AASOP increase the performance of MANETs by minimizing data transfer delay which in turn increases Packet Delivery Ratio (PDR).