The Dynamic Source Routing protocol (DSR) is a simple and efficient
routing protocol designed specifically for use in multi-hop wireless
ad hoc networks of mobile nodes. DSR allows the network to be
completely self-organizing and self-configuring, without the need for
any existing network infrastructure or administration. The protocol is
composed of the two mechanisms of "Route Discovery" and "Route
Maintenance", which work together to allow nodes to discover and
maintain source routes to arbitrary destinations in the ad hoc
network. The use of source routing allows packet routing to be
trivially loop-free, avoids the need for up-to-date routing
information in the intermediate nodes through which packets are
forwarded, and allows nodes forwarding or overhearing packets to cache
the routing information in them for their own future use. All aspects
of the protocol operate entirely on-demand, allowing the routing
packet overhead of DSR to scale automatically to only that needed to
react to changes in the routes currently in use. This document
specifies the operation of the DSR protocol for routing unicast IP
packets in multi-hop wireless ad hoc networks.

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The Dynamic Source Routing Protocol (DSR) for Mobile Ad Hoc Networks for IPv4

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 MANETs characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future. � 2003 Elsevier B.V. All rights reserved.

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Mobile ad hoc networking: imperatives and challenges

Wireless networks are built upon a shared medium that makes it easy for adversaries to launch jamming-style attacks. These attacks can be easily accomplished by an adversary emitting radio frequency signals that do not follow an underlying MAC protocol. Jamming attacks can severely interfere with the normal operation of wireless networks and, consequently, mechanisms are needed that can cope with jamming attacks. In this paper, we examine radio interference attacks from both sides of the issue: first, we study the problem of conducting radio interference attacks on wireless networks, and second we examine the critical issue of diagnosing the presence of jamming attacks. Specifically, we propose four different jamming attack models that can be used by an adversary to disable the operation of a wireless network, and evaluate their effectiveness in terms of how each method affects the ability of a wireless node to send and receive packets. We then discuss different measurements that serve as the basis for detecting a jamming attack, and explore scenarios where each measurement by itself is not enough to reliably classify the presence of a jamming attack. In particular, we observe that signal strength and carrier sensing time are unable to conclusively detect the presence of a jammer. Further, we observe that although by using packet delivery ratio we may differentiate between congested and jammed scenarios, we are nonetheless unable to conclude whether poor link utility is due to jamming or the mobility of nodes. The fact that no single measurement is sufficient for reliably classifying the presence of a jammer is an important observation, and necessitates the development of enhanced detection schemes that can remove ambiguity when detecting a jammer. To address this need, we propose two enhanced detection protocols that employ consistency checking. The first scheme employs signal strength measurements as a reactive consistency check for poor packet delivery ratios, while the second scheme employs location information to serve as the consistency check. Throughout our discussions, we examine the feasibility and effectiveness of jamming attacks and detection schemes using the MICA2 Mote platform.

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The feasibility of launching and detecting jamming attacks in wireless networks

Security has become a primary concern in order to provide protected communication between mobile nodes in a hostile environment. Unlike the wireline networks, the unique characteristics of mobile ad hoc networks pose a number of nontrivial challenges to security design, such as open peer-to-peer network architecture, shared wireless medium, stringent resource constraints, and highly dynamic network topology. These challenges clearly make a case for building multifence security solutions that achieve both broad protection and desirable network performance. In this article we focus on the fundamental security problem of protecting the multihop network connectivity between mobile nodes in a MANET. We identify the security issues related to this problem, discuss the challenges to security design, and review the state-of-the-art security proposals that protect the MANET link- and network-layer operations of delivering packets over the multihop wireless channel. The complete security solution should span both layers, and encompass all three security components of prevention, detection, and reaction.

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Security in mobile ad hoc networks: challenges and solutions

In contrast with conventional networks, mobile ad hoc networks usually do not provide online access to trusted authorities or to centralized servers, and they exhibit frequent partitioning due to link and node failures and to node mobility. For these reasons, traditional security solutions that require online trusted authorities or certificate repositories are not well-suited for securing ad hoc networks. We propose a fully self-organized public-key management system that allows users to generate their public-private key pairs, to issue certificates, and to perform authentication regardless of the network partitions and without any centralized services. Furthermore, our approach does not require any trusted authority, not even in the system initialization phase.

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Self-organized public-key management for mobile ad hoc networks

In this paper we present a survey of secure ad hoc routing protocols for mobile wireless networks. A mobile ad hoc network is a collection of nodes that is connected through a wireless medium forming rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organized networks do not address possible threats aiming at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence several efforts have been made towards the design of a secure and robust routing protocol for ad hoc networks. We briefly present the most popular protocols that follow the table-driven and the source-initiated on-demand approaches. Based on this discussion we then formulate the threat model for ad hoc routing and present several specific attacks that can target the operation of a protocol. In order to analyze the proposed secure ad hoc routing protocols in a structured way we have classified them into five categories; solutions based on asymmetric cryptography, solutions based on symmetric cryptography, hybrid solutions, reputation-based solutions and a category of add-on mechanisms that satisfy specific security requirements. A comparison between these solutions can provide the basis for future research in this rapidly evolving area.

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Secure routing for mobile ad hoc networks

The past few years have witnessed an explosive growth in the use of wireless mobile handheld devices as the enabling technology for accessing Internet-based services, as well as for personal communication needs in ad hoc networking environments. Most studies indicate that it is impossible to utilize strong cryptographic functions for implementing security protocols on handheld devices. Our work refutes this. Specifically, we present a performance analysis focused on three of the most commonly used security protocols for networking applications, namely SSL, S/MIME and IPsec. Our results show that the time taken to perform cryptographic functions is small enough not to significantly impact real-time mobile transactions and that there is no obstacle to the use of quite sophisticated cryptographic protocols on handheld mobile devices.

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Performance analysis of cryptographic protocols on handheld devices

A mobile ad hoc network is a collection of nodes that are connected through a wireless medium and form rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organised networks do not address possible threats aimed at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence several efforts have been made towards the design of a secure routing protocol for ad hoc networks. The main problems with this approach are that it requires changes to the underlying routing protocol and that manual configuration of the initial security associations cannot be completely avoided. We propose RIDAN, a novel architecture that uses knowledge-based intrusion detection techniques to detect, in real-time, attacks that an adversary can perform against the routing fabric of a mobile ad hoc network. Our system is designed to take countermeasures minimising the effectiveness of an attack and maintaining the performance of the network within acceptable limits. RIDAN does not introduce any changes to the underlying routing protocol since it operates as an intermediate component between the network traffic and the utilised protocol with minimum processing overhead. We have developed a prototype that was evaluated in AODV-enabled networks using the ns-2 network simulator.

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Real-time intrusion detection for ad hoc networks

As the vision of ubiquitous computing becomes reality smart devices are embedded into our surroundings and domestic appliances providing services transparently. The nature of such smart computing environments is open and dynamic; therefore the use of predefined security associations between all of the participating devices is particularly difficult. Our proposal, called AETHER, defines a security management architecture designed specifically to address access control and the establishment of associations in smart environments. Attribute authority sets and access control policy entries are embedded into pervasive devices defining initial trust relationships. Members of the attribute authority sets are trusted to issue credentials for the corresponding attributes that can then be used to gain access to services provided by smart devices. We allow these sets to grow dynamically without requiring manual reconfiguration facilitating decentralized administration, which is required in volatile pervasive environments, and attribute mapping to allow roaming among smart authority domains.

Securing Communications in the Smart Home

The management of dynamic spectrum access requires the coordination of administrative functions across multiple organizations, from regulators to secondary market operators and commons cooperatives. Policy-based management approaches to dynamic spectrum access must therefore support a wide range of organizational types and handle the relationships between policies authored separately within those organizations. A policy language for administering dynamic access to spectrum resources has been proposed by the DARPA XG initiative. This defines an expressive and extensible language for specifying policies that determine the correct behavior of RF transceivers as spectrum usage opportunities occur. However, this language does not yet address the mapping of policies onto the complex organizational settings that are likely to emerge in the dynamic spectrum access domain. This paper defines how the DARPA XG policy language can be integrated with a meta-policy management scheme that provides the powerful organizational modeling and policy authoring authority control needed to manage the evolution of policies in these complex organizational settings. The benefits of this integration are illustrated through a case study based on the potential use of dynamic spectrum access licenses granted in Ireland for the DySpan 2007 conference, and the organizational conflicts that even this simple scenario can yield. The practical issues of administering a multi-organizational policy management system are examined through an analysis of the interactions between existing components that are being assembled to demonstrate sophisticated policy management of a cognitive radio system.

Patroklos Argyroudis

Papers

Secure routing for mobile ad hoc networks

Performance analysis of cryptographic protocols on handheld devices

Real-time intrusion detection for ad hoc networks

Securing Communications in the Smart Home

Grouping Abstraction and Authority Control in Policy-Based Spectrum Management