Ashraf Matrawy

MPEG4 traffic modeling using the transform expand sample methodology

The transfer of digital video will be a crucial component of the design of future home networking applications. This transfer was made feasible by the advancement of digital video encoding techniques that reduced the bandwidth required for this transfer to a practical level. MPEG4 is an encoding technique that is suitable for home networking applications with its low bit rate. It also has the advantage that allows viewers to interact with encoded objects. In this paper, we present our work that enables the study of MPEG4 properties and performance on the Internet using simulation. We propose a traffic generator that is able to generate traffic that has almost the same first and second order statistics as an original trace of MPEG4 frames that is generated using an MPEG4 encoder. We model and generate this traffic based on the transform expand sample (TES) methodology using TEStool. We present the model and show the performance of the generator in terms of good matching of the characteristics of the modeled trace.

Smart wireless sensor network management based on software-defined networking

In this position paper, we propose the use of software-defined networking (SDN) in wireless sensor networks (WSNs) for smart management. We argue that smart management using SDN promises a solution to some of inherent problems in WSN management. Furthermore, we propose a generic architecture for a base station in a software-defined wireless sensor network. We also propose a general framework for a software-defined wireless sensor network where the controller is implemented at the base station. We then raise some important questions that need to be investigated in future research in software-defined wireless sensor networks.

A survey of congestion control schemes for multicast video applications

Congestion control for IP multicast on the Internet has been one of the main issues that challenge a rapid deployment of IP multicast. In this article, we survey and discuss the most important congestion control schemes for multicast video applications on the Internet. We start with a discussion of the different elements of a multicast congestion control architecture. A congestion control scheme for multicast video possesses specific requirements for these elements. These requirements are discussed, along with the evaluation criteria for the performance of multicast video. We categorize the schemes we present into end-to-end schemes and router-supported schemes. We start with the end-to-end category and discuss several examples of both single-rate multicast applications and layered multicast applications. For the router-supported category, we first present single-rate schemes that utilize filtering of multicast packets by the routers. Next we discuss receiver-based layered schemes that rely on routers group/flow control of multicast sessions. We evaluate a number of schemes that belong to each of the two categories.

Mitigating network denial-of-service through diversity-based traffic management

In this paper we explore the feasibility of mitigating network denial-of-service (NDoS) attacks (attacks that consume network bandwidth) by dynamically regulating learned classes of network traffic. Our classification technique clusters packets based on the similarity of their contents – both headers and payloads – using a variation of n-grams which we call (p,n)-grams. We then allocate shares of bandwidth to each of these clusters using an adaptive traffic management technique. Our design intent is that excessive bandwidth consumers (e.g. UDP worms, flash crowds) are segregated so that they cannot consume bandwidth to the exclusion of other network traffic. Because this strategy, under congestion conditions, increases the packet drop rate experienced by sets of similar flows and thus reduces the relative drop rate of other, dissimilar flows, we characterize this strategy as diversity-based traffic management. We explain the approach at a high level and report on preliminary results that indicate that network traffic can be quickly and concisely learned, and that this classification can be used to regulate the bandwidth allocated to both constant packet and polymorphic flash UDP worms.

Bottleneck Analysis of Traffic Monitoring using Wireshark

This paper looks at the bottlenecks associated with packet capturing using commodity hardware in local area networks (LANs) without losing data. Experiments were carried out using the Wireshark packet sniffer to write captured packets directly to disk in a Fast Ethernet network with various test setups. These experiments involved generating large packets at almost line rate. Various sizes of the kernel level buffer associated with the packet capturing socket were also experimented with. As well, a simple multithreaded design with user level buffers was proposed for the capturing application and experiments were carried out with this solution. The results showed that increasing the buffering at either the kernel level or the application level can significantly improve capturing performance. The best results can be achieved by using a mix of increased kernel socket buffering and a multithreaded capturing application with its own store and hold buffers.

An energy optimizing scheduler for mobile cloud computing environments

In mobile cloud computing, mobile devices seek to minimize computation time and/or energy consumption based on task related or user defined constraints. In earlier work [1], we proposed to minimize the total energy consumption across all the mobile devices in a cyber foraging system using a scheduler that runs in a centralized broker node, in situations where a large number of mobile devices could be expected. In this paper, we extend our earlier task scheduling problem for a large number of mobile devices to a mobile cloud computing environment. We optimally solve the task scheduling problem for task assignment to minimize the total energy consumption across the mobile devices subject to user defined constraints. Our task scheduler model at the centralized broker optimally offloads tasks and provides significant reduction in energy consumption compared to the energy consumption when tasks are offloaded from the centralized scheduler without optimization.

A Survey on Botnet Architectures, Detection and Defences

Botnets are known to be one of the most serious Internet security threats. In this survey, we review botnet architectures and their controlling mechanisms. Botnet infection behavior is explained. Then, known botnet models are outlined to study botnet design. Furthermore, Fast-Flux Service Networks (FFSN) are discussed in great details as they play an important role in facilitating botnet traffic. We classify botnets based on their architecture. Our classification criterion relies on the underlying CC C&C traffic, bot generated traffic, and DNS traffic, (2) botmaster traceback detection, and (3) botnet detection using virtual machines. Finally, we summarize botnet defence measures that should be taken after detecting a botnet.

A classification of web browser fingerprinting techniques

As the World Wide Web has increasingly become a necessity in daily life, the acute need to safeguard user privacy and security has become manifestly apparent. After users realized that browser cookies could allow websites to track their actions without permission or notification, many have chosen to reject cookies in order to protect their privacy. However, more recently, methods of fingerprinting a web browser have become an increasingly common practice. In this paper, we classify web browser fingerprinting into four main categories: (1) Browser Specific, (2) Canvas, (3) JavaScript Engine, and (4) Cross-browser. We then summarize the privacy and security implications, discuss commercial fingerprinting techniques, and finally present some detection and prevention methods.

A rate adaptation algorithm for multicast sources in priority-based IP networks

This article presents a new rate adaptation algorithm for multicast sources that operate in priority-based IP networks. The algorithm represents the flow control component of our work on an architecture for video multicasting in priority-based IP networks. We show (through simulation results) that the algorithm meets our design goal of satisfying the quality of service (QoS) requirements of different video multicast receivers which have different networking capabilities.

On layered video fairness on IP networks

In this paper, we present a study of layered video fairness on IP networks. Our study is based on simulation. We investigate some issues that have direct impact on fair allocation of bandwidth between layered video and TCP, in particular: (a) congestion control mechanisms employed by layered video transfer protocols; for this part we studied the interaction of RLM with TCP; (b) the effect of the distribution of video traffic across layers in layered multicast video; (c) the effect of VBR video on fairness to TCP. We show that fairness is affected by all the above factors. We also show that fairness of layered video comes at the expense of instability of the video quality and poor link utilization. We conclude by discussing the performance of layered video protocols in general and recommendations on the design of video transfer systems on IP networks.