Ohjelmoitava saumaton moniliitettävyys

Our devices have become accustomed to being always connected to the Internet. Our devices from handheld devices, such as smartphones and tablets, to our laptops and even desktop PCs are capable of using both wired and wireless networks, ranging from mobile networks such as 5G or 6G in the future to Wi-Fi, Bluetooth, and Ethernet. The applications running on the devices can use different transport protocols from traditional TCP and UDP to state-of-the-art protocols such as QUIC. However, most of our applications still use TCP, UDP, and other protocols in a similar way as they were originally designed in the 1980s, four decades ago. The transport connections are a single path from the source to the destination, using the end-to-end principle without taking advantage of the multiple available transports. Over the years, there have been a lot of studies on both multihoming and multipath protocols, i.e., allowing transports to use multiple paths and interfaces to the destination. Using these would allow better mobility and more efficient use of available transports. However, Internet ossification has hindered their deployment. One of the main reasons for the ossification is the IPv4 Network Address Translation (NAT) introduced in 1993, which allowed whole networks to be hosted behind a single public IP address. Unfortunately, how this many-to-one translation should be done was not standardized thoroughly, allowing vendors to implement their own versions of NAT. While breaking the end-to-end principle, the different versions of NATs also behave unpredictably when encountering other transport protocols than the traditional TCP and UDP, from forwarding packets without translating the packet headers to even discarding the packets that they do not recognize. Similarly, in the context of multiconnectivity, NATs and other middleboxes such as firewalls and load balancers likely prevent connection establishment for multipath protocols unless they are specially designed to support that particular protocol. One promising avenue for solving these issues is Software-Defined Networking (SDN). SDN allows the forwarding elements of the network to remain relatively simple by separating the data plane from the control plane. In SDN, the control plane is realized through SDN controllers, which control how traffic is forwarded by the data plane. This allows controllers to have full control over the traffic inside the network, thus granting fine-grained control of the connections and allowing faster deployment of new protocols. Unfortunately, SDN-capable network elements are still rare in Small Office / Home Office (SOHO) networks, as legacy forwarding elements that do not support SDN can support the majority of contemporary protocols. The most glaring example is the Wi-Fi networks, where the Access Points (AP) typically do not support SDN, and allow traffic to flow between clients without the control of the SDN controllers. In this thesis, we provide a background on why multiconnectivity is still hard, even though there have been decades worth of research on solving it. We also demonstrate how the same devices that made multiconnectivity hard can be used to bring SDN-based traffic control to wireless and SOHO networks. We also explore how this SDN-based traffic control can be leveraged for building a network orchestrator for controlling and managing networks consisting of heterogeneous devices and their controllers. With the insights provided by the legacy devices and programmable networks, we demonstrate two different methods for providing multiconnectivity; one using network-driven programmability, and one using a userspace library, that brings different multihoming and multipathing methods under one roof.Nykyisin kaikki käyttämämme laitteet ovat käytännössä aina yhteydessä Internettiin. Laitteemme voivat käyttää useita erilaisia yhteystapoja, mukaanlukien sekä langallisia, että langattomia verkkoja, kuten Wi-Fi ja mobiiliverkkoja. Kuitenkin laitteemme käyttävät pääsääntöisesti edelleen tietoliikenneprotokollia, jotka suunniteltiin alunperin 1980-luvulla. Tällöin laitteet pystyivät viestimään suoraan toistensa kanssa ilman, että välissä oli verkkolaitteita, jotka piilottivat osia verkosta taakseen. Tämä näkyy protokollien suunnittelussa siten, että jokaisella yhteydellä on määritetyt lähde- ja kohdeosoitteet. Nykyisin laitteemme käyttävät edelleen samaa yhteysparadigmaa, vaikka ne voisivat niputtaa yhteen useampia tietoliikenneyhteyksiä. Tällöin saisimme paremmin käyttöön verkon tarjoaman suorituskyvyn ja muut ominaisuudet. Vuosien saatossa on kehitetty erilaisia monitie (eng. multipath) ja moniyhteys (eng. multihoming) tietoliikenneprotokollia, joiden avulla laitteet pystyvät käyttämään useampia polkuja verkon yli kohteeseensa. Nämä protokollat eivät kuitenkaan ole vielä yleistyneet, sillä kaikki verkkolaitteet eivät tue niitä. Emme myöskään pysty vaikuttamaan kuin ainoastaan epäsuorasti siihen, mitä yhteyttä laitteemme käyttävät. Yksi ratkaisu on tähän ottaa käyttöön ohjelmallisesti määritetyt verkot (eng. Software-Defined Networking, SDN). SDN on paradigma, jonka avulla verkkoihin voidaan tuoda älykkyyttä ja mahdollistaa mm. tehokkaampi liikenteen reititys verkoissa. Tämän väitöskirjatutkimuksen tarkoituksena on käsitellä moniliitettävyyden ongelmia ja ratkaisuja. Tutkimus valottaa miksi moniliitettävyys on edelleen hankala toteuttaa, sekä esittelee kaksi tekniikkaa toteuttaa moniliitettävyys. Ensimmäinen tekniikka soveltaa ohjelmallisesti määritettyjä verkkoja käyttäen hyväkseen väitöskirjan aikana tehtyä tutkimusta, ja toinen tekniikka kerää saman katon alle useita erilaisia monitie- ja moniyhteysprotokollia yhdeksi moniliitettävyyskirjastoksi. Väitöskirjassa esitellään myös kaksi menetelmää tuoda ohjelmallisesti määritetyt verkot laitteisiin, joita ei ole suunniteltu niitä silmällä pitäen. Näiden menetelmien avulla voidaan hallita ja tuoda uusia ominaisuuksia jo olemassa oleviin verkkoihin. Väitöskirjassa esitellään myös koneoppimista soveltava älykäs järjestelmä, joka havaitsee ja poistaa automaattisesti haavoittuvia laitteita verkosta

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

Practical issues of implementing a hybrid multi-NIC wireless mesh-network

Testbeds are a powerful tool to study wireless mesh and sensor networks as close as possible to real world application scenarios. In contrast to simulation or analytical approaches these installations face various kinds of environment parameters. Challenges related to the shared physical medium, operating system, and used hardware components do arise. In this technical report about the work-in-progress Distributed Embedded Systems testbed of 100 routers deployed at the Freie Universität Berlin we focis on the software architecture and give and introduction to the network protocol stack of the Linux kernel. Furthermore, we discuss our first experiences with a pilot network setup, the encountered problems and the achieved solutions. This writing continues our first publication and builds upon the discussed overall testbed architecture, our experiment methodology, and aspired research objectives

QOE-AWARE CONTENT DISTRIBUTION SYSTEMS FOR ADAPTIVE BITRATE VIDEO STREAMING

A prodigious increase in video streaming content along with a simultaneous rise in end system capabilities has led to the proliferation of adaptive bit rate video streaming users in the Internet. Today, video streaming services range from Video-on-Demand services like traditional IP TV to more recent technologies such as immersive 3D experiences for live sports events. In order to meet the demands of these services, the multimedia and networking research community continues to strive toward efficiently delivering high quality content across the Internet while also trying to minimize content storage and delivery costs. The introduction of flexible and adaptable technologies such as compute and storage clouds, Network Function Virtualization and Software Defined Networking continue to fuel content provider revenue. Today, content providers such as Google and Facebook build their own Software-Defined WANs to efficiently serve millions of users worldwide, while NetFlix partners with ISPs such as ATT (using OpenConnect) and cloud providers such as Amazon EC2 to serve their content and manage the delivery of several petabytes of high-quality video content for millions of subscribers at a global scale, respectively. In recent years, the unprecedented growth of video traffic in the Internet has seen several innovative systems such as Software Defined Networks and Information Centric Networks as well as inventive protocols such as QUIC, in an effort to keep up with the effects of this remarkable growth. While most existing systems continue to sub-optimally satisfy user requirements, future video streaming systems will require optimal management of storage and bandwidth resources that are several orders of magnitude larger than what is implemented today. Moreover, Quality-of-Experience metrics are becoming increasingly fine-grained in order to accurately quantify diverse content and consumer needs. In this dissertation, we design and investigate innovative adaptive bit rate video streaming systems and analyze the implications of recent technologies on traditional streaming approaches using real-world experimentation methods. We provide useful insights for current and future content distribution network administrators to tackle Quality-of-Experience dilemmas and serve high quality video content to several users at a global scale. In order to show how Quality-of-Experience can benefit from core network architectural modifications, we design and evaluate prototypes for video streaming in Information Centric Networks and Software-Defined Networks. We also present a real-world, in-depth analysis of adaptive bitrate video streaming over protocols such as QUIC and MPQUIC to show how end-to-end protocol innovation can contribute to substantial Quality-of-Experience benefits for adaptive bit rate video streaming systems. We investigate a cross-layer approach based on QUIC and observe that application layer-based information can be successfully used to determine transport layer parameters for ABR streaming applications

Future Trends and Challenges for Mobile and Convergent Networks

Some traffic characteristics like real-time, location-based, and community-inspired, as well as the exponential increase on the data traffic in mobile networks, are challenging the academia and standardization communities to manage these networks in completely novel and intelligent ways, otherwise, current network infrastructures can not offer a connection service with an acceptable quality for both emergent traffic demand and application requisites. In this way, a very relevant research problem that needs to be addressed is how a heterogeneous wireless access infrastructure should be controlled to offer a network access with a proper level of quality for diverse flows ending at multi-mode devices in mobile scenarios. The current chapter reviews recent research and standardization work developed under the most used wireless access technologies and mobile access proposals. It comprehensively outlines the impact on the deployment of those technologies in future networking environments, not only on the network performance but also in how the most important requirements of several relevant players, such as, content providers, network operators, and users/terminals can be addressed. Finally, the chapter concludes referring the most notable aspects in how the environment of future networks are expected to evolve like technology convergence, service convergence, terminal convergence, market convergence, environmental awareness, energy-efficiency, self-organized and intelligent infrastructure, as well as the most important functional requisites to be addressed through that infrastructure such as flow mobility, data offloading, load balancing and vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and Services, Nova Science Publishers, 201

Toward a broadband service delivery model over wireless technologies to resource-constrained public high schools in South Africa

Information and Communication Technologies (ICTs) are capable of expanding access to quality education, educational resources, and also provide teachers with new skills. Nevertheless, a majority of rural public schools have limited ICTs, mainly due to geographical landscape, lack of service delivery and poverty. As a result, they currently seem not to be adequately benefiting from current advancements in ICTs. The main objective of this research study was to investigate an appropriate broadband services delivery model using wireless access technologies, such as a Global System for Mobile communication (GSM) and Enhanced data rates for GSM Evolution (EDGE) to deliver electronic-based educational information to resource-constrained public high schools. An exploratory case study approach was adopted to identify and understand the challenges faced by rural schools in the Greater Tubatse Municipality (GTM), including educational services and content considered by the schools as relevant and useful. The research results indicate that resource-constrained schools in the GTM are facing challenges of lack of access to electronic educational information and services, and as a result, teaching and learning becomes limiting and challenging. Based on the research findings, the results show that having access to learning material via electronic platforms could afford educators and learners the opportunity to interact with the outside world, improve learning and teaching and benefit the community as a whole. The broadband services delivery conceptual model (BSDCM) was proposed, developed and evaluated to address the lack of electronic educational information and services for resource-constrained public high schools. The BSDCM is composed of both technical and non-technical components that consider requirements of all role players, ICT challenges, policy makers and Information Communication Technology for Education (ICT4ED) interventions. The proposed model addressed some of the challenges regarding lack of access to educational content. However, it is recommended that the ICT4ED policies governing the use of mobile devices in the classrooms be introduced by the relevant authorities. In addition, a comparative analysis of other network technologies should be conducted to establish if the TCP/IP header compression on Point to Point Protocol (PPP) improves the performance of the network in resource-constrained environments. Furthermore, it is recommended that further research and experiments be conducted to determine if other various third party content providers could create and deploy various educational services and content for different computing platforms using the proposed BSDCM.School of ComputingM. Tech (Information Technology

Managed access dependability for critical services in wireless inter domain environment

The Information and Communications Technology (ICT) industry has through the last decades changed and still continues to affect the way people interact with each other and how they access and share information, services and applications in a global market characterized by constant change and evolution. For a networked and highly dynamic society, with consumers and market actors providing infrastructure, networks, services and applications, the mutual dependencies of failure free operations are getting more and more complex. Service Level Agreements (SLAs) between the various actors and users may be used to describe the offerings along with price schemes and promises regarding the delivered quality. However, there is no guarantee for failure free operations whatever efforts and means deployed. A system fails for a number of reasons, but automatic fault handling mechanisms and operational procedures may be used to decrease the probability for service interruptions. The global number of mobile broadband Internet subscriptions surpassed the number of broadband subscriptions over fixed technologies in 2010. The User Equipment (UE) has become a powerful device supporting a number of wireless access technologies and the always best connected opportunities have become a reality. Some services, e.g. health care, smart power grid control, surveillance/monitoring etc. called critical services in this thesis, put high requirements on service dependability. A definition of dependability is the ability to deliver services that can justifiably be trusted. For critical services, the access networks become crucial factors for achieving high dependability. A major challenge in a multi operator, multi technology wireless environment is the mobility of the user that necessitates handovers according to the physical movement. In this thesis it is proposed an approach for how to optimize the dependability for critical services in multi operator, multi technology wireless environment. This approach allows predicting the service availability and continuity at real-time. Predictions of the optimal service availability and continuity are considered crucial for critical services. To increase the dependability for critical services dual homing is proposed where the use of combinations of access points, possibly owned by different operators and using different technologies, are optimized for the specific location and movement of the user. A central part of the thesis is how to ensure the disjointedness of physical and logical resources so important for utilizing the dependability increase potential with dual homing. To address the interdependency issues between physical and logical resources, a study of Operations, Administrations, and Maintenance (OA&M) processes related to the access network of a commercial Global System for Mobile Communications (GSM)/Universal Mobile Telecommunications System (UMTS) operator was performed. The insight obtained by the study provided valuable information of the inter woven dependencies between different actors in the delivery chain of services. Based on the insight gained from the study of OA&M processes a technological neutral information model of physical and logical resources in the access networks is proposed. The model is used for service availability and continuity prediction and to unveil interdependencies between resources for the infrastructure. The model is proposed as an extension of the Media Independent Handover (MIH) framework. A field trial in a commercial network was conducted to verify the feasibility in retrieving the model related information from the operators' Operational Support Systems (OSSs) and to emulate the extension and usage of the MIH framework. In the thesis it is proposed how measurement reports from UE and signaling in networks are used to define virtual cells as part of the proposed extension of the MIH framework. Virtual cells are limited geographical areas where the radio conditions are homogeneous. Virtual cells have radio coverage from a number of access points. A Markovian model is proposed for prediction of the service continuity of a dual homed critical service, where both the infrastructure and radio links are considered. A dependability gain is obtained by choosing a global optimal sequence of access points. Great emphasizes have been on developing computational e cient techniques and near-optimal solutions considered important for being able to predict service continuity at real-time for critical services. The proposed techniques to obtain the global optimal sequence of access points may be used by handover and multi homing mechanisms/protocols for timely handover decisions and access point selections. With the proposed extension of the MIH framework a global optimal sequence of access points providing the highest reliability may be predicted at real-time

Optimizing transmission protocols for enhancement of quality of service in telemedical realtime applications

In der Dissertation mit dem Titel „Optimierung von Übertragungsprotokollen zur Verbesserung der Dienstgüte in telemedizinischen Echtzeitanwendungen“ geht es um die Entwicklung einer Protokollmodifikation für Multipath-TCP zur besseren Unterstützung von telemedizinischen Echtzeitanwendungen über das Internet in einem Szenario zwischen global verteilten Standorten. Das Ziel von redundantem Multipath-TCP (rMPTCP) ist es, mehrere Verbindungen gleichzeitig zu nutzen, um mithilfe von Redundanz Verzögerungsspitzen und Datenverluste auszugleichen und somit die Dienstgüte der Übertragung zu verbessern. Hierbei passt sich das Protokoll den aktuellen Gegebenheiten der Datenverbindung adaptiv an, indem es Redundanz, Leitungsqualität, benötigte Datenübertragungsrate sowie den durch das Netzwerk angebotenen Datendurchsatz in Relation setzt. Anwendungen in der Telemedizin unterscheiden sich in ihren kommunikativen und interaktiven Ausprägungen und damit in ihren Dienstgüteanforderungen. Zu diesem Zweck werden grundlegende Anwendungen in der Telemedizin sowie Spezifizierungen der Dienstgüteanforderungen der anfallenden Datenströme behandelt und klassifiziert. Dies geschieht in Hinblick auf ein zwischen der Universität Duisburg-Essen (UDE) und der Universiti Kebangsaan Malaysia (UKM) laufendes Forschungsszenario. Darauf folgt eine Darlegung von Dienstgüte-Mechanismen im Internet. Darin werden die elementaren Funktionsweisen sowie Möglichkeiten diese zu verbessern beschrieben. Die Übertragungsstrecke zwischen den beiden Universitäten wird entsprechend des Basisszenarios in Hinblick auf verschiedene Dienstgüteparameter mit entsprechenden Messwerkzeugen soweit ausgewertet, dass Gegebenheiten und Probleme identifiziert werden können. Eine Evaluierung der verschiedenen verfügbaren Verbindungen zwischen UDE und UKM dient der Ermittlung einer kombinierten Nutzungsweise und den Möglichkeiten bei einer Mehrfachverbindung. Die Modellierung und Entwicklung der Protokollmodifikation wird unter den vorher hergeleiteten Anforderungen durchgeführt. Es werden die grundsätzlichen mathematischen Zusammenhänge diskutiert und eine Einführung in die Funktionalitäten des Protokolls gegeben. Die Eigenschaften und Funktionen des neuen Protokolls werden modelliert und zusätzliche Hilfsmittel, die für die Anwendung innerhalb des Szenarios benötigt werden entwickelt. Die Funktionalitäten werden in praktischen Versuchen ausgewertet und eine abschließende Beurteilung diskutiert. Das Ergebnis dieser Dissertation ist die Entwicklung einer internetkompatiblen redundanten Protokollerweiterung für Multipath-TCP, die in der Lage ist, sich mithilfe verschiedener Algorithmen auf Situationen im Netzwerk anzupassen und verschiedene Maßnahmen bei Störungen zu ergreifen. Die Protokollerweiterung ist in der Lage, eine Dienstgüteverbesserung in Hinblick auf Verzögerungen sowie Verzögerungsvarianzen für Anwendungen mit „Nahe-Echtzeit“-Anforderungen zu erreichen.In the dissertation entitled "Optimization of Transmission Protocols to Improve Quality of Service in Telemedicine Real-Time Applications", the aim is to develop a protocol modification for Multipath-TCP to improve the support for telemedical real-time applications over the Internet in a scenario between globally distributed locations. The goal of redundant Multipath TCP (rMPTCP) is to use multiple connections at the same time to compensate for delay and data losses by means of redundancy and thus to improve the quality of service of the transmission. The protocol adapts to the current circumstances of the data connection by correlating redundancy, connection quality, required data transmission rate as well as the data throughput offered by the network. Applications in telemedicine differ in their communicative and interactive manifestations and thus in their quality of service requirements. For this purpose, basic applications in telemedicine as well as specifications of the quality requirements of the resulting data streams are treated and classified. This is done with regard to a research scenario running between the University of Duisburg-Essen (UDE) and the Universiti Kebangsaan Malaysia (UKM). It is followed by a presentation of quality of service mechanisms on the Internet. The basic functions as well as ways to improve them are described. The transmission distance between the two universities is evaluated according to the basic scenario with regard to different quality of service parameters with appropriate measuring tools in a way that conditions and problems can be identified. An evaluation of the various available connections between UDE and UKM is used to determine a combined usage and the possibilities for a multiple connection. The modeling and development of the protocol modification is performed under the previously-derived requirements. The basic mathematical connections are discussed and an introduction to the functionalities of the protocol is given. The properties and functions of the new protocol are modeled and additional tools developed for utilization within the scenario are designed. The functionalities are evaluated in practical tests and a final assessment is discussed. The result of this dissertation is the development of an Internet-compatible redundant protocol extension for multipath TCP, which is able to adapt to situations in the network by means of different algorithms and to take various measures in case of disturbances. The protocol extension is capable of achieving an improvement in service quality with regard to delays as well as delay variances for applications with "near real-time" requirements

Building the Future Internet through FIRE

The Internet as we know it today is the result of a continuous activity for improving network communications, end user services, computational processes and also information technology infrastructures. The Internet has become a critical infrastructure for the human-being by offering complex networking services and end-user applications that all together have transformed all aspects, mainly economical, of our lives. Recently, with the advent of new paradigms and the progress in wireless technology, sensor networks and information systems and also the inexorable shift towards everything connected paradigm, first as known as the Internet of Things and lately envisioning into the Internet of Everything, a data-driven society has been created. In a data-driven society, productivity, knowledge, and experience are dependent on increasingly open, dynamic, interdependent and complex Internet services. The challenge for the Internet of the Future design is to build robust enabling technologies, implement and deploy adaptive systems, to create business opportunities considering increasing uncertainties and emergent systemic behaviors where humans and machines seamlessly cooperate