Amitabh Mishra

QoS issues in ad hoc wireless networks

Ad hoc wireless networks consist of mobile nodes interconnected by multihop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of the network changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. This article addresses some of the quality of service issues for ad hoc networks which have started to receive increasing attention in the literature. The focus is on QoS routing. This is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information. We present the basic concepts and discuss some of the results. The article concludes with some observations on the open areas for further investigation.

Intrusion detection in wireless ad hoc networks

Intrusion detection has, over the last few years, assumed paramount importance within the broad realm of network security, more so in the case of wireless ad hoc networks. These are networks that do not have an underlying infrastructure; the network topology is constantly changing. The inherently vulnerable characteristics of wireless ad hoc networks make them susceptible to attacks, and it may be too late before any counter action can take effect. Second, with so much advancement in hacking, if attackers try hard enough they will eventually succeed in infiltrating the system. This makes it important to constantly (or at least periodically) monitor what is taking place on a system and look for suspicious behavior. Intrusion detection systems (IDSs) do just that: monitor audit data, look for intrusions to the system, and initiate a proper response (e.g., email the systems administrator, start an automatic retaliation). As such, there is a need to complement traditional security mechanisms with efficient intrusion detection and response. In this article we present a survey on the work that has been done in the area of intrusion detection in mobile ad hoc networks.

Collaborative security architecture for black hole attack prevention in mobile ad hoc networks

An ad hoc network is a group of wireless mobile computers (or nodes) wherein individual nodes cooperate by forwarding packets for each other to allow nodes to communicate beyond direct wireless transmission range. The Black hole attack is an important problem that could happen easily in ad hoc networks especially in popular on-demand protocols like the ad hoc on-demand distance vector routing (AODV). Prior research in ad hoc networking has generally looked into the routing problem in a non-adversarial network setting, assuming a reasonably trusted environment. This paper proposes a collaborative architecture to detect and exclude malicious nodes that act in groups or alone. The focus is on the network layer, using the ad hoc on-demand distance vector routing (AODV) protocol as an example. This paper describes an extension to the watchdog method to incorporate a collaborative architecture to tackle collusion among nodes.

An optimal GTS scheduling algorithm for time-sensitive transactions in IEEE 802.15.4 networks

IEEE 802.15.4 is a new enabling standard for low-rate wireless personal area networks and has been widely accepted as a de facto standard for wireless sensor networking. While primary motivations behind 802.15.4 are low power and low cost wireless communications, the standard also supports time and rate sensitive applications because of its ability to operate in TDMA access modes. The TDMA mode of operation is supported via the Guaranteed Time Slot (GTS) feature of the standard. In a beacon-enabled network topology, the Personal Area Network (PAN) coordinator reserves and assigns the GTS to applications on a first-come-first-served (FCFS) basis in response to requests from wireless sensor nodes. This fixed FCFS scheduling service offered by the standard may not satisfy the time constraints of time-sensitive transactions with delay deadlines. Such operating scenarios often arise in wireless video surveillance and target detection applications running on sensor networks. In this paper, we design an optimal work-conserving scheduling algorithm for meeting the delay constraints of time-sensitive transactions and show that the proposed algorithm outperforms the existing scheduling model specified in IEEE 802.15.4.

Quality of service challenges for wireless mobile ad hoc networks

Wireless mobile ad hoc networks consist of mobile nodes interconnected by wireless multi-hop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of such networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. Supporting appropriate quality of service for mobile ad hoc networks is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information, and has become an intensely active area of research in the last few years. This paper1 presents the basic concepts of quality of service support in ad hoc networks for unicast communication, reviews the major areas of current research and results, and addresses some new issues. The principal focus is on routing and security issues associated with quality of service support. The paper concludes with some observations on the open areas for further investigation. Copyright

A Multi-channel MAC for Opportunistic Spectrum Sharing in Cognitive Networks

The spectrum of deployed wireless cellular communication systems is found to be under-utilized, even though licensed spectrum is at a premium. To efficiently utilize the band-width left unused in a cellular system, which we denote as the primary system (PRI), we design a system with an ad hoc/mesh overlay network, which we denote as the secondary system (SEC). The basic design principle is that the SEC operates in a non-intrusive manner and does not interact with the PRI. We develop a multi-channel MAC protocol, to enable the interoperation of the PRI-SEC system. We address a number of technical challenges pertinent to this networking environment, and evaluate the performance of MAC. Our performance evaluation results show that, in a single-hop ASN, the AS-MAC transparently utilizes 75% of the bandwidth left unused by the PRI, while, in multi-hop ASNs, due to spatial reuse, the AS-MAC can utilize significantly higher number of the idle PRI resources

A self-adaptive clustering based algorithm for increased energy-efficiency and scalability in wireless sensor networks

Wireless sensor networks (WSNs) represent a new dimension in the field of networking. The collaboration of large numbers of networked sensors revolutionizes the multitude of applications where WSNs can be applied, in the near future. In this paper we suggest a self-adaptive clustering based scheme for WSNs. A dynamic clustering scheme for the self-configuration of nodes in the WSN is discussed. We also outline a self-adapting algorithm for optimizing the sleep times of the nodes in the cluster by adapting to varying traffic loads. Our discussion aims to produce a reliable and robust sensing network, that promises more energy saving, scalability, and increased lifetime for the WSN. We do not base our discussion in this paper on any specific application, and expect our scheme to hold for all generic applications where WSNs can be used.

A novel intrusion detection approach for wireless ad hoc networks

The potential for rapid and infrastructure-less deployment in harsh geographic terrain as well as in conference-room like scenarios has propelled research on wireless ad hoc networks (MANETs). However, these networks are vulnerable to attackers due to certain inherently vulnerable characteristics. With intrusion prevention measures not guaranteed to work all the time, the need to constantly monitor what is going on in a system and look for intrusions is fulfilled by intrusion detection systems (IDS). In this paper we have proposed a novel and robust IDS for MANETs that aims to combine misuse with anomaly detection. Our protocol-independent design makes use of a self-adjusting threshold scheme that detects a priori known attack patterns with over 90% accuracy and is generally insensitive to false alarms. Experimental results indicate the non-degradability of network performance when our IDS is incorporated in the routing algorithm for security enhancements.

Intrusion detection in MANETS - the second wall of defense

Wireless mobile ad hoc networks (popularly known as MANETs) have been the focus of research in recent times. Rapid and infrastructure-less deployment in emergency and military situations make these networks unique. However, certain inherently vulnerable characteristics lead to security concerns, which can prove especially damaging in sensitive situations like military operations. Intrusion prevention measures are not guaranteed to work all the time since unrelenting attackers can eventually break them down. An intrusion detection scheme (IDS) monitors a network and looks for intrusions, thus forming a second wall of defense. In this paper, we have proposed a misuse detection -based IDS for MANETs. Our protocol-independent design makes use of a self-adjusting threshold scheme and detects a priori known attack patterns with over 90% accuracy and is generally insensitive to false alarms. Experimental validation has provided significant results about non-degradability of network performance with our IDS incorporated for security enhancements.

Cloud computing: networking and communication challenges

Over the past few years, cloud computing has rapidly emerged as a widely accepted computing paradigm built around core concepts such as on-demand computing resources, elastic scaling, elimination of up-front capital and operational expenses, and establishing a pay-as-you-go business model for computing and information technology services. With the widespread adoption of virtualization, service oriented architectures, and utility computing there has been a significant development in the creation of cloud support structures to deliver IT services within QoS bounds, service level agreements, and security and privacy requirements.