In this paper, we present a delay based routing algorithm for ad hoc wireless networks. In an ad hoc environment there is no wired infrastructure and the mobile hosts work as a router to maintain the status about the connectivity. A mobile ad hoc network is an autonomous collection of mobile users (nodes) that communicates over relatively bandwidthconstrained wireless links. Each node is equipped with wireless receivers and transmitters using antennas that may be omnidirectional, highly directional, or possibly steer able. Due to nodal mobility, the network topology may change rapidly and unpredictably over time. The network is decentralized, where network organization and message delivery must be executed by the nodes themselves, i.e., routing functionally will be incorporated into mobile nodes. The design of the network protocols for mobile ad hoc network is a complex issue. These networks need efficient distributed algorithm to determine network organization (connectivity), link scheduling, and routing. But, the existing routing algorithms designed for ad hoc wireless networks have slow response, excessive overhead and become unsuitable under the above considerations. The full approach, for referring the internal state of the network relies on Round Trip Time (RTT) measurements only. We consider the RTT mean and RTT variance as fuzzy input variables and delay as a fuzzy output variable. Under such condition the performance of the proposed algorithm is tested. It is shown that under these conditions the algorithm gives better results. The proposed routing algorithm is simulated in MATLAB 6.5.
Pervasive computing is an exciting and blooming research field, in which innovative techniques and applications are continuously emerging and aim to provide ambient and personalized services to users with high quality. Ad hoc networks are wireless, self-organizing systems formed by co-operating nodes within communication range of each other that form temporary networks. Their topology is dynamic, decentralized, ever changing and the nodes may move around arbitrarily. The last few years have witnessed a wealth of research ideas on ad hoc networking that are moving rapidly into implemented standards. Technology under development for ad hoc networks and pervasive computing is making important steps toward this end goal possible. However, the security concerns remain a serious impediment to widespread adoption. The underlying radio communication medium for wireless network provides serious exposure to attacks against wireless networks. Wireless ad hoc networks usually cannot depend on traditional infrastructure found in enterprise environments such as dependable power sources, high bandwidth, continuous connectivity, common network services, well-known membership, static configuration, system administration, and physical security. Finally, throw in malicious adversaries with Byzantine collusion threats and you have a very interesting and challenging problem. Without adequate security, enterprises will not be able to profit from the use of wireless ad hoc networks and pervasive computing environment, defense organizations might be unable to guarantee the safety of their personnel in battlefield scenarios, and wireless ad hoc networks and pervasive computing will remain on the drawing board even if the other problems associated with them are solved. This special issue is focused on various aspects of security in ad hoc networks and pervasive computing research and development to report both in-depth research and applications-oriented works. The special issue is intended to foster state-of-the-art research in the area of security in ad hoc networks and pervasive computing. The aim of this special issue is to present a collection of high quality research papers that report the latest research advances in security of ad hoc. In this special issue, we selected seven papers, which can demonstrate advanced works in this field. A detailed overview of the selected works is given below. The first paper, An RC4-Based Lightweight Protocol for Secure Data Transmission on Resource-Constrained Devices, presents a simple, lightweight, but robust security protocol based on the backward property of RC4 stream cipher. The proposed protocol provides data confidentiality, data authentication, data integrity, and data freshness with low overhead and simple operation, allows packets be received in an arbitrary order, achieves semantic security, and does not require frequent key renew. The second paper, PAPA-UIC: A Design Approach and a Framework for Secure Mobile Ad-hoc Networks, proposes a new design approach and a framework for securing a practical type of MANETs. The framework is named PAPA-UIC. The paper proposes a secure routing protocol and solutions to general problems of identity-based cryptography. The routing protocol has several improvements over existing ones. The third paper, RFIDGuard: A Lightweight Privacy and Authentication Protocol for Passive RFID Tags, introduces a protocol which requires little computation and achieves both privacy and authentication simultaneously. The lightweight and secure nature of the RFIDGuard protocol make it particularly suitable for supply chain management. The fourth paper, Using Hidden Markov Model to Detect Rogue Access Points, proposes a statistical based approach to detect rogue access points using a Hidden Markov Model, which is applied to passively measure packet-header data collected at a gateway router. The main idea is to process the sequence of packet traces in order to distinguish the normal packets from the abnormal ones. The approach is scalable and non-intrusive, requiring little deployment cost and effort, and is easy to manage and maintain. The fifth paper, Defending Sybil Attacks Based on Neighboring Relations in Wireless Sensor Networks, develops a mechanism to protect a WSN from Sybil attacks without using any authentication-based method. Furthermore, the detection approach requires no specialized hardware or support devices. The feature that a malicious node creates many fake identities is exploited to distinguish legitimate nodes from Sybil/malicious nodes. Since all of the fake identities forged by the same malicious node are associated with the same physical device, they will have the same legitimate neighbors. Therefore, by collecting the neighboring information of the suspected victim of the Sybil attacks, the legitimate nodes which are the neighbors of the malicious nodes can be determined. In contrast to existing protection schemes, this approach has no requirement for shared keys, secret information, or special hardware support. The sixth paper, An Autonomous Attestation Token to Secure Mobile Agents in Disaster Response, introduces the Autonomous Attestation Token (AAT), a hardware token for mobile computing devices that is capable of guaranteeing the trusted state of a limited set of devices without relying on a networked service. The paper proposes a Local Attestation protocol with user interaction that in conjunction with the AAT prevents unauthorized access to an emergency mobile agent platform. In addition, the paper sketches a possible solution which integrates trusted computing to leverage ad hoc networks and peer-to-peer systems to provide a robust communication platform. The seventh paper, Building Advanced Applications with the Belgian eID, introduces the Belgian Electronic Identity Card. The card enables Belgian citizens to digitally prove their identity and to sign electronic documents. This paper presents two reusable extensions to the Belgian eID technology that opens up new opportunities for application developers. First, a secure and ubiquitously accessible remote storage service is presented. Second, it is shown how the eID card can be used to issue new certificates. The feasibility and reusability of both extensions are validated through the development of several applications in different domains. In conclusion, this issue of Security in Ad hoc offers a groundbreaking view into the recent advances in secure ad hoc networks. This issue offers both academic and industry appeal the former as a basis toward future research directions, and the latter toward viable commercial applications. Finally, we would like to express our gratitude to the Editor-in-Chief, Professor HsiaoHwa Chen for his advice, patience, and encouragements since the beginning until the final stage. Special thanks go to Michelle in Wiley during the production. We thank all anonymous reviewers who spent much of their precious time reviewing all the papers. Their timely reviews and comments greatly helped us select the best papers in this special issue. We also thank all authors who have submitted their papers for consideration for this issue. We hope you will enjoy reading the great selection of papers in this issue.
Gabriele Monti, Gianluca Moro, Marco Rosetti, Giacomo Tufano
The work presents a decentralized protocol that allows self-organization of autonomous wireless devices in mobile mesh networks. In the resulting infrastructure the routing and information services are provided in a peer-to- peer fashion. Both services are performed through multi- hop radio transmissions among participant nodes with no fixed infrastructure required and avoiding to use broadcast of messages. Since links among nodes may be continuously destroyed and created, as a consequence of nodes movement and/or variations in connectivity range (e.g. due to temporary obstacles), our protocol is based on virtual network addresses which are dynamically assigned to groups of nodes (called islands). Routing requests are performed through unicast transmissions when traveling among islands and exploiting wireless overhearing when involving members of the same island (in- island routing). We will demonstrate that assigning virtual coordinates to groups of nodes guarantees network flexibility with a reasonable amount of overheard and that the amount of radio transmissions required is scalable with the number of nodes. Simulations have shown that the proposed solution can generate reliable networks, despite the unpredictable topology, assuming the use of devices with common radio range connectivity moving at pedestrian velocity.
Gartner has for some time been reporting the potential for virtual world technology to become the next wave of the Internet, delivering what is known as the Web3.D environment. This is characterised by a high level of user participation through immersion in the virtual world. Gartner has predicted that by 2011, 80% of internet users will be regular users of Web3.D technology.\n\nProject LifeLink was initiated to discover what opportunities for Telecom might exist in the growth of business and consumer interest in virtual worlds. This has focused on a number of technologies, in particular Second Life, OpenSimulator (OpenSIM) and JAIN SLEE. The project has been run by Telecom with coordination and support from MediaLab, and with researchers at Canterbury and Otago Universities. This report describes the work undertaken at Otago University to implement a gateway to enable demonstration of communications between an object in Second Life and the JAIN SLEE environment in order to interoperate with external network services.
Networked systems are continuously growing in scale and complexity. The technical and policy engineering challenges introduced by such a fast growth are currently addressed locally, with limited understanding of their impact on the whole. Such approaches are becoming impractical and insufficient. Next-generation networks need to address these issues by deploying adaptive and self-managing protocols and mechanisms to relax the persistent need for human-driven management. However, achieving these objectives requires conceptual, physical, and logistical modifications to existing systems and protocols. To this end, the traditional top-down approach to network and application design needs to be supplemented by understanding the bottom-up nature of evolving real-world networks.A critical issue that is significantly impacting computer networks and applications is the absence of an in-depth understanding and lack of control over the structural properties, i.e., topology, of large networks. Network topologies define the link relationships between the nodes in the network, and have a direct impact on the performance, resilience, and security of distributed applications. Large scale networks such as the Internet are the result of a time evolving process in which nodes and links between nodes are added, removed, and reconfigured dynamically. This dynamic process takes place in a decentralized manner during which nodes make local adaptations and reconfiguration decisions that optimize local properties. As a result, these local perturbations yield an emergent network that is often unstructured and complex, and have implications at the application-level, particularly impacting routing, search, robustness, and clustering. Understanding the structures emerging out of these adaptations is a complex problem part of the science and study of complexity theory and complex adaptive systems. Tackling this complex problem requires first, identifying canonical metrics to quantify the network topology and second, analyzing the impact of local perturbations of these metrics on the resulting network topology.This thesis identifies three local metrics, transitivity, assortativity, and entropy, and analyzes the impact of their perturbation on the applications of routing, search, robustness, and clustering. The local metric of network entropy is identified as a useful information theoretic measure of homogeneity of a network neighborhood degree. The metric is further used to derive a novel mechanism of clustering detection of the network topology. The overall objective of this thesis is to investigate metrics and mechanisms to better understand the evolution of the network topology and its impact on application-level functionality. The approach is based on concepts of emergence, self-organization and graph theory, and has three key aspects: (1) the identification of canonical local and global graph metrics; (2) the quantitative analysis of the impact of local perturbations on global properties; and (3) the application of the local to global mapping on the problems of routing, search, robustness, and clustering. Adaptations are performed in a decentralized manner in which local nodes use local information to add, remove, or rewire an edge to evolve the topology. Simulations based on annealing optimization are conducted to empirically determine the optimal bounds of the network structures for the selected metrics on selected networks. Further experiments on two modeled networks, random and power-law degree distributed, and two real-world networks, the Gnutella and Canadian Autonomous System networks, show that the impact of optimizing networks with fixed degree distribution on local metrics yield networks with routing, search, robustness, and clustering that are tightly dependent on the network's degree distribution. A key outcome of this thesis is the identification of network entropy minimization as a useful local rewiring strategy to decrease average path length and search cost, while homogenizing the size of network clusters and having a low impact on robustness when applied to power-law degree distributed networks that prevail in real-world networks.
Xu Wang, Yang Ji, Xiaosheng Tang, Yinong Li · 5 authors
Our objective is to build a distributed terminal system to provide smart, context-aware, rich-experienced applications upon personal environment networking technologies, such as WLAN, IEEE 802.15.3 series, ZigBee, Bluetooth, etc. For the proliferation of smart devices with autonomous applications, the users can get much more service experiences than before. While smart devices facilitate human operation, the coordination of devices through networks may provide applications proactively by gathering much more service context, which indicates the emergence of the pervasive computing age. Hence, we proposed the distributed terminal system for the cooperating of smart devices. In this paper, we analyzed the organization architecture of universal service terminal (UST), the distributed terminal system proposed by us before. In UST project, we have abstracted and encapsulated the capabilities of devices as servers for remote invocation by applications, moreover, the framework functionalities have been introduced for the organization of the distributed system. Though the architecture of UST has been validated feasible in a demonstration, the centralized control mechanisms in the heterogeneous environment are inefficient and unreliable. Thus, we propose an evolved scheme by introducing decentralized mechanisms in this paper. The devices around the user are organized in an overlay peer-to-peer network, and some powerful nodes of them provide the decentralized mechanisms for resource management, service discovery, etc
Philipp Obreiter, Birgitta König‐Ries, Michael Klein
In the context of mobile and wireless devices, an information system is no longer a centralized component storing all the relevant data nor is it a decentralized component governed by a common authority. Rather, the information spread across huge numbers of autonomous mobile and wireless devices owned by independent organizations and individuals can be regarded as a highly dynamic, virtual information system. For this vision to become reality, the autonomous devices involved need to be motivated to cooperate. This cooperation needs to occur not only on the application layer, but, depending on the network architecture, also on the lower layers from the link layer on upwards. In this report, we investigate on which protocol layers cooperation is needed and what constitutes uncooperative behavior. We then identify necessary properties of incentive schemes that encourage cooperation and discourage uncooperative behavior. In this context, we examine remuneration types that are a major constituent of incentive schemes. Finally, using the example of ad hoc networks, the most challenging technical basis of a wireless information system, we compare existing incentive schemes to these characteristics.