Raja Datta

Collaborative techniques for intrusion detection in mobile ad-hoc networks

In this paper, we present two intrusion detection techniques for mobile ad-hoc networks, which use collaborative efforts of nodes in a neighborhood to detect a malicious node in that neighborhood. The first technique is designed for detection of malicious nodes in a neighborhood of nodes in which each pair of nodes in the neighborhood are within radio range of each other. Such a neighborhood of nodes is known as a clique[12]. The second technique is designed for detection of malicious nodes in a neighborhood of nodes, in which each pair of nodes may not be in radio range of each other but where there is a node among them which has all the other nodes in its one-hop vicinity. This neighborhood is identical to a cluster as mentioned in [12]. Both techniques use message passing between the nodes. A node called the monitor node initiates the detection process. Based on the messages that it receives during the detection process, each node determines the nodes it suspects to be malicious and send votes to the monitor node. The monitor node upon inspecting the votes determines the malicious nodes from among the suspected nodes. Our intrusion detection system is independent of any routing protocol. We give the proof of correctness of the first algorithm, which shows that it correctly detects the malicious nodes always when there is no message loss. We also show with the help of simulations that both the algorithms give good performance even when there are message losses arising due to unreliable channel.

Light-weight trust-based routing protocol for mobile ad hoc networks

Mobile ad hoc networks (MANETs) were originally designed for a cooperative environment. To use them in hostile environments, trust-based routing can be used, where instead of establishing the shortest routes as done in traditional routing protocols, most trusted routes are established. In this study, the authors present a light-weight trust-based routing protocol. It is light-weight in the sense that the intrusion detection system (IDS) used for estimating the trust that one node has for another, consumes limited computational resource. Moreover, it uses only local information thereby ensuring scalability. Our light-weight IDS takes care of two kinds of attacks, namely, the blackhole attack and the grey hole attack. Whereas our proposed approach can be incorporated in any routing protocol, the authors have used AODV as the base routing protocol to evaluate our proposed approach and give a performance analysis.

A secure dynamic IP configuration scheme for mobile ad hoc networks

Secure dynamic IP addressing is a prime requirement for unicast communication between authorized hosts in mobile ad hoc networks (MANETs). Recently, several approaches have been proposed for dynamic addressing scheme. However, most of the approaches rely on broadcasting for address solicitation and/or duplicate address detection. As a result, several types of security threats in dynamic IP configuration can be observed. In this paper, we present an ID based dynamic IP configuration scheme that can securely allocate IP addresses to the authorized hosts for a mobile ad hoc network without broadcasting over the entire network. Each host in the MANET can generate an unique IP address from its own IP address for a new host. The proposed scheme provides authentication for address configuration without the help of a trusted third party while taking care of the security-threats associated with dynamic IP configuration. Performance analysis shows that even with added security mechanisms our proposed addressing scheme has fairly good addressing latency and control overhead compared to the similar existing schemes. Moreover, the proposed scheme is able to solve the problem of network partitions and mergers along with the arrival and departure of a host efficiently and securely.

Multihop Virtual Topology Design in WDM Optical Networks for Self-Similar Traffic

In this paper, we consider the problem of designing virtual topologies for multihop optical WDM networks when the traffic is self-similar in nature. Studies over the last few years suggest that the network traffic is bursty and can be much better modeled using self similar process instead of Poisson process. We examine buffer sizes of a network and observe that, even with reasonably low buffer overflow probability, the maximum buffer size requirement for self-similar traffic can be very large. Therefore, a self-similar traffic model has an impact on the queuing delay which is usually much higher than that obtained with the Poisson model. We investigate the problem of constructing the virtual topology with these two types of traffic and solve it with two algorithmic approaches: Greedy (Heuristic) algorithm and Evolutionary algorithm. While the greedy algorithm performs a least-cost search on the total delay along paths for routing traffic in a multihop fashion, the evolutionary algorithm uses genetic methods to optimize the average delay in a network. We analyze and compare our proposed algorithms with an existing algorithm via different performance parameters. Interestingly, with both the proposed algorithms the difference in the queuing delays, caused by self-similar and Poisson traffic, results in different multihop virtual topologies.

A trust based protocol for energy-efficient routing in self-organized MANETs

Mobile ad-hoc network (MANET) is an energy constraint multi-hop network and its nodes have routing capability with limited battery power. In such a network, establishing a correct and efficient route is a crucial design issue. But a more challenging goal is to provide an energy-efficient multi-hop route between source-destination pair. Thus, the routing protocols should setup an energy-efficient route between source-destination pair considering the energy consumption and residual energy of the nodes. Cooperative transmission, a recent technology, optimizes energy consumption of the nodes in the networks. The trust based routing mechanism is one way to form a cooperation among nodes for establishing an energy-efficient route between source-destination pair. In this paper, we first introduce an energy consumption model to calculate the energy-factor1 of the nodes and then propose a trust based protocol for energy-efficient routing. We also adopt a trust module to track the value of routing metric. Simulation results show that our proposed protocol reduces delay, routing overhead, and increases packet delivery ratio by consuming less energy compared to AODV and DSR, the popular existing routing protocols.

Busy tone contention protocol: a new high-throughput and energy-efficient wireless local area network medium access control protocol using busy tone

Design of an efficient wireless medium access control (MAC) protocol is a challenging task due to the time-varying characteristics of wireless communication channel and different delay requirements in diverse applications. To support variable number of active stations and varying network load conditions, random access MAC protocols are employed. Existing wireless local area network (WLAN) protocol (IEEE 802.11) is found to be inefficient at high data rates because of the overhead associated with the contention resolution mechanism employed. The new amendments of IEEE 802.11 that support multimedia traffic (IEEE 802.11e) are at the expense of reduced data traffic network efficiency. In this paper, we propose a random access MAC protocol called busy tone contention protocol (BTCP) that uses out-of-band signals for contention resolution in WLANs. A few variants of this protocol are also proposed to meet the challenges in WLAN environments and application requirements. The proposed BTCP isolate multimedia traffics from background data transmissions and gives high throughput irrespective of the number of contending stations in the network. As a result, in BTCP, admission control of multimedia flows becomes simple and well defined. Studies of the protocol, both analytically and through simulations under various network conditions, have shown to give better performance in comparison with the IEEE 802.11 distributed coordination function. Copyright

An algorithm for optimal assignment of a wavelength in a tree topology and its application in WDM networks

In this paper, we present a polynomial time algorithm that gives an optimal solution to the routing and wavelength assignment (RWA) problem in a tree topology. One of the major design issues in wavelength-division multiplexed networks is the assignment of the limited number of wavelengths among network stations so that greater capacity can be achieved. The problem of RWA is known to be NP-hard problem. Many researchers have tackled the problem of RWA with a number of efficient heuristic algorithms. This paper presents an algorithm that optimally assigns a single wavelength to maximize one-hop traffic in a tree topology. The algorithm uses dynamic programming and is shown to be optimal with a time complexity of O(N/sup 4/). We also propose a heuristic scheme to use our optimal algorithm for wavelength assignment in a general graph. The heuristic works on the tree subgraphs of a given graph and the remaining spare wavelengths can be assigned with an existing RWA policy.

ADIP: an improved authenticated dynamic IP configuration scheme for mobile ad hoc networks

Dynamic IP configuration is a major requirement for mobile ad hoc networks that grows from one node to many. Recently, a number of schemes for such IP assignments have been proposed in the literature. But very few of them consider security aspects while assigning the addresses among the nodes. In this paper, we propose an authenticated dynamic IP configuration scheme that can securely allocate IP addresses to the individual nodes of a MANET. In this scheme, each node of a MANET can generate new unique IP address from its own IP address for a new authenticated host. The authentication for address configuration is done with the help of a trusted third party and as such it is capable of handling the security threats associated with a general dynamic IP configuration. Performance analysis and simulation results show that, even while deploying the security attributes, the communication overhead and addressing latency of our proposed addressing scheme are at par with and in some cases much better than some popular similar existing schemes.

A two-tier strategy for priority based critical event surveillance with wireless multimedia sensors

Surveillance plays a vital role in protecting infrastructure facilities of a country and improving detection of cross-border activities. Compared to traditional surveillance systems, wireless multimedia sensor networks (WMSN) provide distinct advantages. In this paper we consider the problem of critical event surveillance in a region of interest with the help of WMSN. The challenge here is deployment cost, energy-efficient routing and preservation of coverage and connectivity of the network. To keep the deployment cost minimum, we propose a two-tier strategy consisting of (a) densely deployed low cost audio tier nodes and (b) sparsely placed high cost video tier nodes to monitor critical events occurring in a given area. The audio nodes perform the preliminary event detection task, whereas, the base station activates the rotatable-video nodes on a demand basis. Depending upon the cost of potential damage, an event is assigned a priority, and based upon that priority an event is assigned either energy efficient or a delay tolerant path along the audio and video tiers. We also propose two integer linear programming formulations MEAT and MEVT for minimization of energy consumption in audio and video tiers separately. We then present two approaches, namely Greedy and DCSEG, and compare them with a popular existing approach under various scenarios. Simulation results show considerable reduction in the number of active audio and video sensor nodes per event which leads to low deployment cost and reduction of average energy consumption in the network.

CoopMACA: a cooperative MAC protocol using packet aggregation

In this paper we propose a cooperative MAC protocol for Wireless Local Area Networks (WLAN) that involves the concept of cooperation among nodes to avoid the negative effect caused by multi rate modulation employed in IEEE 802.11 standards. In our proposed protocol a low data rate direct transmission link is replaced by two faster transmission links using a relay node. During transmission, each node selects either direct or indirect transmission (through a helper node) in order to minimize the total transmission time and utilizes the packet aggregation concept to improve the system throughput. The new protocol does not violate the inter frame space specified in IEEE 802.11 and shows compatibility with the standard. We give the mathematical analysis that shows that our proposed protocol increases the system throughput considerably in comparison to the existing ones. The analytical results are supported with the help of simulation. We have shown how this protocol can be implemented in combination with others to improve the system throughput in specific network scenarios.