Md. Shariful Islam

SHWMP: a secure hybrid wireless mesh protocol for IEEE 802.11s wireless mesh networks

In recent years, mesh networking has emerged as a key technology for the last mile Internet access and found to be an important area of research and deployment. The current draft standard of IEEE 802.11s has defined routing for Wireless Mesh Networks (WMNs) in layer-2 and is termed as Hybrid Wireless Mesh Protocol (HWMP). However, security in routing or forwarding functionality is not specified in the standard. As a consequence, HWMP in its current from is vulnerable to various types of routing attacks such as flooding, route disruption and diversion, spoofing etc. In this paper, we propose SHWMP, a secure HWMP protocol for WMN. The proposed protocol uses cryptographic extensions to provide authenticity and integrity of HWMP routing messages and prevents unauthorized manipulation of mutable fields in the routing information elements. We show via analysis that the proposed SHWMP successfully thwarts all the identified attacks. Through extensive ns-2 simulations, we show that SHWMP provides higher packet delivery ratio with little increase in end-to-end delay, path acquisition delay and control byte overhead.

A Secure Hybrid Wireless Mesh Protocol for 802.11s Mesh Network

Wireless Mesh Network (WMN) has emerged as a key technology and found a great deal of interest for the researchers in the recent past. Hybrid Wireless Mesh Protocol (HWMP) is the default path selection (i.e., routing) protocol fully specified in the current draft D.1.06 of 802.11s for WMN. However, security in routing or forwarding functionality is not specified in the standard. As a consequence, HWMP in its current from is vulnerable to various types of routing attacks. In this paper, we propose a secure version of HWMP (SHWMP) that operates similarly to that of HWMP but uses cryptographic extensions to provide authenticity and integrity of routing messages and prevents unauthorized manipulation of mutable fields in the routing information elements. We have shown through analyses and simulation that SHWMP is robust against identified attacks and provides higher packet delivery ratio and incurs little computational and storage overhead to ensure security.

Enhanced Channel Access Mechanism for IEEE 802.11s Mesh Deterministic Access

This paper presents an enhanced channel access mechanism for the newly introduced Mesh Deterministic Access (MDA) mechanism for IEEE 802.11s based Wireless Mesh Networks (WMNs). The MDA is an optional scheduled access mechanism which enables mesh nodes to negotiate periodic transmission opportunity (referred to as Mesh Deterministic Access Opportunity (MDAOP)) for a collision free transmission of QoS frames. However, the performance of MDA is affected by the presence of contention from non-MDA nodes in the neighborhood. In this work, we first identify how a non-MDA node affects the operation of MDA and then, propose an enhanced channel access mechanism referred to as Enhanced Mesh Deterministic Access (EMDA) that ensures guaranteed access to the medium during an MDAOP by an MDA-owner by means of reduced Interframe Space (IFS) and the preemption capability. Finally, we study the performance of EMDA through simulation, and results show that EMDA outperforms others in terms of throughput, end-to-end delay, packet loss rate and MDA utilization.

EFT: a high throughput routing metric for IEEE 802.11s wireless mesh networks

In this paper, we present a throughput-maximizing routing metric, referred to as expected forwarding time (EFT), for IEEE 802.11s-based wireless mesh networks. Our study reveals that most of the existing routing metrics select the paths with minimum aggregate transmission time of a packet. However, we show by analyses that, due to the shared nature of the wireless medium, other factors, such as transmission time of the contending nodes and their densities and loads, also affect the performance of routing metrics. We therefore first identify the factors that hinder the forwarding time of a packet. Furthermore, we add a new dimension to our metric by introducing traffic priority into our routing metric design, which, to the best of our knowledge, is completely unaddressed by existing studies. We also show how EFT can be incorporated into the hybrid wireless mesh protocol (HWMP), the path selection protocol used in the IEEE 802.11s draft standard. Finally, we study the performance of EFT through simulations under different network scenarios. Simulation results show that EFT outperforms other routing metrics in terms of average network throughput, end-to-end delay, and packet loss rate.

Fair data collection in wireless sensor networks: analysis and protocol

In general, wireless sensor networks (WSNs) consist of many sensors which transmit data to a central node, called the sink, possibly over multiple hops. This many-to-one data routing paradigm leads to nonuniform traffic distribution for the different sensors (e.g., nodes closer to the sink transfer more traffic than those farther away). In this paper, we perform an analysis of the fairness issue by presenting a tree-based WSN and derive the throughput, delay, and energy distribution for each sensor under the fairness constraint. Based on the analysis, we design our fair data collection protocol in which each node decides its media access and packet forwarding strategies in a distributed manner. Finally, we demonstrate the effectiveness of our solution through simulations. The results for the proposed protocol show the accuracy of the analysis and show that the protocol ensures the fair delivery of packets and reduces end-to-end delay. Based on the analysis, we also quantitatively determine the energy required for each of the nodes and show that a nonuniform energy distribution can maximize the network lifetime for the WSN scenario under study.

Developing Security Solutions for Wireless Mesh Enterprise Networks

Our study on the deployment topology and communication characteristics of wireless mesh enterprise networks (WMENs) leads to three critical security challenges: (a) deployment of network devices are not planar, rather devices are deployed over three-dimensional space, (b) message generated/received by a mesh client traverses through mesh routers in a multi-hop fashion, and (c) mesh clients being mostly mobile in nature may result in misbehaving or spurious during communications. We address these challenges for WMENs that may be a small network within an office or a medium-size network for all offices in an entire building, or a large scale network among offices in multiple buildings. We develop a matrix key distribution technique that perfectly suits the network topology. A session key establishment protocol is presented to achieve the client-router and router-router communication security. Finally, a misbehaving client detection algorithm is developed based on the communication history. We analyze and evaluate the performance to show the suitability of our proposed security solutions.

Misbehavior Detection in Wireless Mesh Networks

In this paper we propose a detection technique to identify misbehaving client in wireless mesh networks. The technique is devised based on the communication history for two communicating clients through a common set of routers. Individual trust relationship is calculated for both the clients with their common routers. Then a correlation value for each client is found and compared with a predefined threshold to determine whether a client is spurious or not. We evaluate the performance of the proposed detection technique through simulation and results show that the detection efficiency is better with small number of misbehaving clients.

A duty cycle directional MAC protocol for wireless sensor networks

The directional transmission and reception of data packets in sensor networks minimize the interference and thereby increase the network throughput, and thus the Directional Sensor Networks (DSN) are getting popularity. However, the use of directional antenna has introduced new problems in designing the medium access control (MAC) protocol in DSNs including the synchonizaiton of antenna direction of a pair of sender-receiver. In this paper, we have developed a duty cycle MAC protocol for DSNs, namely DCD-MAC, that synchronizes each pair of parent-child nodes and schedules their transmissions in such a way that transmission from child nodes minimizes the collision and the nodes are awake only when they have transmission-reception activities. The proposed DCD-MAC is fully distributed and it exploits only localized information to ensure weighted share of the transmission slots among the child nodes. We perform extensive simulations to study the performances of DCD-MAC and the results show that our protocol outperforms a state-of-the-art directional MAC protocol in terms of throughput and network lifetime.

Enforcing Fairness for Data Collection in Wireless Sensor Networks

The well known many–to–one data routingparadigm [1] in wireless sensor networks (WSNs) demands non–uniform medium access and forwarding strategy to achieve theultimate node level fairness. Since nodes closer to the sink havemore traffic than that of far–away nodes, close–by nodes needto employ different frequency of media access and forwardingprobability such that sink receives almost equal number ofpackets from all the nodes in the network. In this paper, wedesign a distributed fair data collection protocol where the nodescan decide their media access and packet forwarding strategieswithin the WSN such that a fair throughput can be enjoyed byeach node irrespective of the node’s distance from the sink. Wedemonstrate the effectiveness of our solution through simulationsand results show that the proposed protocol ensures the fairdelivery of packets, improves throughput and reduces end–to–end delay for the different WSN scenarios under study.

A Low Duty Cycle MAC Protocol for Directional Wireless Sensor Networks

Directional communication in wireless sensor networks minimizes interference and thereby increases reliability and throughput of the network. Hence, directional wireless sensor networks (DWSNs) are fastly attracting the interests of researchers and industry experts around the globe. However, in DWSNs the conventional medium access control protocols face some new challenges including the synchronization among the nodes, directional hidden terminal and deafness problems, etc. For taking the advantages of spatial reusability and increased coverage from directional communications, a low duty cycle directional Medium Access control protocol for mobility based DWSNs, termed as DCD-MAC, is developed in this paper. To reduce energy consumption due to idle listening, duty cycling is extensively used in WSNs. In DCD-MAC, each pair of parent and child sensor nodes performs synchronization with each other before data communication. The nodes in the network schedule their time of data transmissions in such a way that the number of collisions occurred during transmissions from multiple nodes is minimized. The sensor nodes are kept active only when the nodes need to communicate with each other. The DCD-MAC exploits localized information of mobile nodes in a distributed manner and thus it gives weighted fair access of transmission slots to the nodes. As a final point, we have studied the performance of our proposed protocol through extensive simulations in NS-3 and the results show that the DCD-MAC gives better reliability, throughput, end-to-end delay, network lifetime and overhead comparing to the related directional MAC protocols.