Advanced Wireless LAN

The past two decades have witnessed starling advances in wireless LAN technologies that were stimulated by its increasing popularity in the home due to ease of installation, and in commercial complexes offering wireless access to their customers. This book presents some of the latest development status of wireless LAN, covering the topics on physical layer, MAC layer, QoS and systems. It provides an opportunity for both practitioners and researchers to explore the problems that arise in the rapidly developed technologies in wireless LAN

Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

Networking Media Abstraction, Device Discovery, and Routing for the Pervasive Middleware PalCom

PalCom is a pervasive middleware that can be used to assemble services provided by networked devices into configurations, called assemblies, for specific use cases by the user. In this dissertation, we present the development of a networking media abstraction framework for PalCom that abstracts different network interfaces in a PalCom device to upper layers of PalCom. The media abstraction framework is documented in paper I. Over the media abstraction layer, we define a device discovery mechanism that enables a PalCom device to discover other devices on its local networks, where it has network interfaces, as well as across interconnected networks. The device discovery mechanism is documented in paper II. On top of the device discovery layer, we implemented support for distance vector routing that enables routing data among discovered devices via the least cost routes. The routing layer is documented in paper III. In the last phase of our work, we refined our device discovery mechanism for PalCom to include a distributed synchronization algorithm that two PalCom nodes can utilize to re-sync their exchanged views of the network to overcome possible loss of device discovery and undiscovery notifications over unreliable channels. The synchronization algorithm is documented in paper IV

Live migration of user environments across wide area networks

A complex challenge in mobile computing is to allow the user to migrate her highly customised environment while moving to a different location and to continue work without interruption. I motivate why this is a highly desirable capability and conduct a survey of the current approaches towards this goal and explain their limitations. I then propose a new architecture to support user mobility by live migration of a user’s operating system instance over the network. Previous work includes the Collective and Internet Suspend/Resume projects that have addressed migration of a user’s environment by suspending the running state and resuming it at a later time. In contrast to previous work, this work addresses live migration of a user’s operating system instance across wide area links. Live migration is done by performing most of the migration while the operating system is still running, achieving very little downtime and preserving all network connectivity. I developed an initial proof of concept of this solution. It relies on migrating whole operating systems using the Xen virtual machine and provides a way to perform live migration of persistent storage as well as the network connections across subnets. These challenges have not been addressed previously in this scenario. In a virtual machine environment, persistent storage is provided by virtual block devices. The architecture supports decentralized virtual block device replication across wide area network links, as well as migrating network connection across subnetworks using the Host Identity Protocol. The proposed architecture is compared against existing solutions and an initial performance evaluation of the prototype implementation is presented, showing that such a solution is a promising step towards true seamless mobility of fully fledged computing environments

Spoofed Networks: Exploitation of GNSS Security Vulnerability in 4G and 5G Mobile Networks

Includes supplementary materialFifth Generation New Radio (5G NR) represents a shift in mobile telephony whereby the network architecture runs containerized software on commodity hardware. In preparation for this transition, numerous 4G Long Term Evolution software stacks have been developed to test the containerization of core network functions and the interfaces with radio access network protocols. In this thesis, one such stack, developed by the OpenAirInterface Software Alliance, was used to create a low-cost, simplified mobile network compatible with the Naval Operational Architecture. Commercial off-the-shelf user equipment was then connected to the network to demonstrate how a buffer overflow vulnerability found in Qualcomm Global Navigation Satellite System chipsets and identified as CVE-2019-2254 can be leveraged to enable a spoofed network attack. The research also yielded an extension of the attack method to 5G NR networks.http://archive.org/details/aplaceholderreco1094567451Lieutenant, United States NavyApproved for public release. Distribution is unlimited

Design and implementation of an on-demand ad-hoc routing algorithm for a positional communication system.

Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.A mobile ad-hoc network is an autonomous network of mobile devices that are connected via wireless links. In such networks there is no pre-existing infrastructure and nodes are free to move in a random fashion. Due to this mobility mobile ad-hoc networks have dynamic topologies. A host in the network typically has limited bandwidth and energy resources. Routing is a major challenge in the development of such systems and there have been many solutions proposed in the recent past. The aim of this work is to design and implement a routing scheme for a Positional Communication System (PCS). The PCS is a network of mobile handheld pocket PCs connected via wireless interfaces. The system allows voice and data communication between nodes in the network. This dissertation addresses the process of designing a routing protocol for an ad-hoc network. There have been many proposed algorithms that solve the routing problem in a mobile ad-hoc network. It is a difficult task to compare the performance of'these protocols qualitatively as there are many parameters that affect network performance. Various simulation packages for networks of this type exist. One such package is the Network Simulator (NS-2). It is a discrete time event simulator that can be used to model wired and wireless networks. This dissertation presents NS-2 simulations that compare four recently proposed routing algorithms. From this comparison study it is shown that on-demand algorithms perform best in a mobile ad-hoc environment. The dissertation then describes the design of a novel on-demand routing algorithm. The ondemand algorithms proposed thus far use a blind flooding technique during the route discovery process. This method is inefficient and creates excessive routing overhead. The routing protocol proposed in the dissertation implements a query localization technique that significantly reduces the network traffic. The protocol also introduces a load checking metric in addition to the metric used by most on-demand schemes, namely hop count. Simulation results show that such a scheme makes the on-demand routing algorithm more efficient and scalable than existing ones. It is widely believed that prior to implementing a routing protocol in real world systems it is essential that it is tested and validated on a test-bed. The dissertation presents the implementation of an on-demand routing algorithm in a Positional Communication System test-bed, where each handheld PC in the network runs an embedded Linux operating system