Wireless meshnet8Ex8 (WMNs)consist of meshrout6L and meshclient8 where meshroutfix have minimal mobilit and formtr backbone of WMNs. They provide netide access for bot mesh andconvent1)fi8 clientt TheintL gratLfl of WMNs wit ot8 net8866 such as t1Int6fiPx1 cellular, IEEE 802.11, IEEE 802.15, IEEE 802.16, sensor netsor1L ets can be accomplishedtccomp tc gatomp and bridging functng1 in t1 meshroutfijx Meshclient can be eit8fi st8fij1)6x or mobile, and can form aclient meshnet16S amongtng1fifiELj and wit meshroutLfifi WMNs are antLfifl1)6fl t resolvets limit18fiflfl andt significantfl improvetp performance of ad hocnetLEP8L wireless local area net1Pxx (WLANs), wireless personal areanet16fij (WPANs), and wirelessmetess1fifljfl areanet1LPS (WMANs). They are undergoing rapid progress and inspiring numerousdeploymentS WMNs will deliver wireless services for a largevariet ofapplicat6fifl in personal, local, campus, andmet8Lfix1)6fi areas. Despit recent advances in wireless mesh netjLfiP1)6 many research challenges remain in allprotjfiS layers. This paperpresent adetEfl81 stEonrecent advances and open research issues in WMNs. Syst1 architL881)6 andapplicat)68 of WMNs are described, followed by discussingts critssi factss influencingprotenc design.Theoret8fiL netore capacit and tdst1LLSjx tt1LL protLLSj for WMNs are exploredwit anobjectE1 t point out a number of open research issues. Finally,tnal beds,indust681 pract68 andcurrent strent actntx1) relatt t WMNs arehighlight8x # 2004 Elsevier B.V. Allrl rl KedI7-8 Wireless meshnet186flfl Ad hocnet8jEES Wireless sensornetor16fl Medium accessconts1fi Routs1 prots1fiS Transport protspor ScalabilitS Securiti Powermanagement andcontfi8fl Timingsynchronizat ion 1389-1286/$ - seefront matt # 2004 Elsevier B.V. Allright reserved. doi:10....

So far, research on mobile ad hoc networks has been focused primarily on routing issues. Security, on the other hand, has been given a lower priority. This paper provides an overview of security problems for mobile ad hoc networks, distinguishing the threats on basic mechanisms and on security mechanisms. It then describes our solution to protect the security mechanisms. The original features of this solution include that (i) it is fully decentralized and (ii) all nodes are assigned equivalent roles.

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, "ad-hoc" network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET's characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future.

We propose a new routing technique called Security-Aware ad hoc Routing (SAR) that incorporates security attributes as parameters into ad hoc route discovery. SAR enables the use of security as a negotiable metric to improve the relevance of the routes discovered by ad hoc routing protocols. We develop a two-tier classi cation of routing protocol security metrics, and propose a framework to measure and enforce security attributes on ad hoc routing paths. Our framework enables applications to adapt their behavior according to the level of protection available on communicating nodes in an ad hoc network.

Sensor networks are ideal candidates for applications such as target tracking and environment monitoring. Security in sensor networks is critical when there are potential adversaries. Establishment of pairwise keys is a fundamental security service, which forms the basis of other security services such as authentication and encryption. However, establishing pairwise keys in sensor networks is not a trivial task, particularly due to the resource constraints on sensors. This paper presents several techniques for establishing pairwise keys in static sensor networks. These techniques take advantage of the observation that in static sensor networks, although it is difficult to precisely pinpoint sensors' positions, it is often possible to approximately determine their locations. This paper presents a simple location-aware deployment model, and develops two pairwise key predistribution schemes, a closest pairwise keys predistribution scheme and a location-based pairwise keys scheme using bivariate polynomials, by taking advantage of sensors' expected locations. The analysis in this paper indicates that these schemes can achieve better performance if such location information is available and that the smaller the deployment error (i.e., the difference between a sensor's actual location and its expected location) is, the better performance they can achieve.

We propose a micro-payment scheme for multi-hop cellular networks that encourages collaboration in packet forwarding by letting users benefit from relaying others' packets. At the same time as proposing mechanisms for detecting and rewarding collaboration, we introduce appropriate mechanisms for detecting and punishing various forms of abuse. We show that the resulting scheme -- which is exceptionally lightweight -- makes collaboration rational and cheating undesirable.

Selfish hosts in wireless networks that fail to adhere to the MAC protocol may obtain an unfair share of the channel bandwidth. We present modifications to the IEEE 802.11 backoff mechanism to simplify detection of such selfish hosts. We also present a correction scheme for penalizing greedy misbehavior which attempts to restrict the misbehaving nodes to a fair share of the channel bandwidth. Simulation results indicate that our detection and correction schemes are fairly successful in handling MAC layer misbehavior.

Mobile ad hoc networking offers convenient infrastructure-free communication over the shared wireless channel. However, the nature of ad hoc networks makes them vulnerable to security attacks. Examples of such attacks include passive eavesdropping over the wireless channel, denial of service attacks by malicious nodes as well as attacks from compromised nodes or stolen devices. Unlike their wired counterpart, infrastructureless ad hoc networks do not have a clear line of defense, and every node must be prepared for encounters with an adversary. Therefore, a centralized or hierarchical network security solution does not work well. This work provides scalable, distributed authentication services in ad hoc networks. Our design takes a self-securing approach, in which multiple nodes (say, k) collaboratively provide authentication services for any node in the network. This paper follows the design guidelines of [7] and makes several new contributions. We first formalize a localized trust model that lays the foundation for the design, and then expand the adversary model that the system should handle. We further propose refined localized certification services, and develop a new scalable solution of share updates to resist more powerful adversaries. Finally, the new solution is evaluated through simulations. 1

The performance of ad hoc networks depends on cooperation and trust among distributed nodes. To enhance security in ad hoc networks, it is important to evaluate trustworthiness of other nodes without centralized authorities. In this paper, we present an information theoretic framework to quantitatively measure trust and model trust propagation in ad hoc networks. In the proposed framework, trust is a measure of uncertainty with its value represented by entropy. We develop four Axioms that address the basic understanding of trust and the rules for trust propagation. Based on these axioms, we present two trust models: entropy-based model and probability-based model, which satisfy all the axioms. Techniques of trust establishment and trust update are presented to obtain trust values from observation. The proposed trust evaluation method and trust models are employed in ad hoc networks for secure ad hoc routing and malicious node detection. A distributed scheme is designed to acquire, maintain, and update trust records associated with the behaviors of nodes ’ forwarding packets and the behaviors of making recommendations about other nodes. Simulations show that the proposed trust evaluation system can significantly improve the network throughput as well as effectively detect malicious behaviors in ad hoc networks.

Protecting the network layer from malicious attacks is an important yet challenging security issue in mobile ad hoc networks. In this paper we describe SCAN, a unified networklayer security solution for such networks that protects both routing and data forwarding operations through the same reactive approach. SCAN does not apply any cryptographic primitives on the routing messages. Instead, it protects the network by detecting and reacting to the malicious nodes. In SCAN, local neighboring nodes collaboratively monitor each other and sustain each other, while no single node is superior to the others. SCAN also adopts a novel credit strategy to decrease its overhead as time evolves. In essence, SCAN exploits localized collaboration and information cross-validation to protect the network in a self-organized manner. Through both analysis and simulation results we demonstrate the effectiveness of SCAN even in a highly mobile and hostile environment.