This thesis contributes to several issues in the context of SDN and NFV, with an emphasis on performance and management. The main contributions are guide lines for operators migrating to software-based networks, as well as an analytical model for the packet processing in a Linux system using the Kernel NAPI. / In der Dissertation werden mehrere Problemstellungen im Kontext von SDN und NFV, vor allem hinsichtlich Performance und Management, bearbeitet. Die Hauptbeiträge sind Guidelines für Netzbetreiber zum Management Software-basierter Netze sowie ein analytisches Modell, welches den Paketverarbeitungsprozess in der Linux Kernel NAPI beschreibt.

<p>The purpose of this thesis work is to examine the possibility of building a software-defined radio (SDR) for the VHF-band. The goal is to accomplish this with as few components as possible, thus cutting down the size and the production cost.</p><p>An SDR solution means that the sampling of the signal is done as close to the antenna as possible. The wide bandwidth needed in such a product is achieved by using SP Devices algorithm for time-interleaved ADCs. Two hardware prototypes and two versions of the software were designed and implemented using this technology.</p><p>They were also analyzed within this thesis work. The results proved to be good, and the possibilities to produce a commercial software-defined radio receiver for the VHF-band are good.</p> / <p>Syftet med det här examensarbetet är att utreda möjligheten att bygga en mjukvarustyrd radiomottagare (SDR) för VHF-bandet. Målet är att göra detta genom att använda så få komponenter som möjligt, och därigenom minska storleken och produktionskostnaden.</p><p>En SDR lösning ger att samplingen kommer att ske så nära antennen som möjligt. Den stora bandbredd som behövs för en sådan produkt uppnås genom att använda SP Devices algoritm för att ''tidsinterleava'' höghastighets ADC:er. Två hårdvaruprototyper och två versioner av mjukvaran har designats och implementerats.</p><p>Analyserna har visat bra resultat, och möjligheterna att bygga en komersiell mjukvarudefinierade radiomottagare för VHF-bandet ses som goda.</p>

The increase in speed and density of programmable logic devices such as Field Programmable Gate Arrays (FPGA) enables ever more complex designs to be constructed within a short time frame. The flexibility of a programmable device eases the integration of a design with a wide variety of components on a single chip. Since Frequency Modulation (FM) is an analog modulation scheme, performing it in the digital domain introduces new challenges. The details of these challenges and how to deal with them are also explained. This thesis presents the design of a digital stereo FM modulator including necessary signal processing, such as filtering, waveform generation, stereo multiplexing etc. The solution is comprised of code written in Very high speed integrated circuit Hardware Description Language (VHDL) and a selection of free Intellectual Property (IP)-blocks and is intended for implementation on a Xilinx FPGA. The focus of the thesis lies on area efficiency and a number of suggestions are given to maximize the number of channels that can be modulated using a single FPGA chip. An estimation of how many channels that can be modulated usingthe provided FPGA, Xilinx XC6SXL100T, is also presented.

The purpose of this thesis work is to examine the possibility of building a software-defined radio (SDR) for the VHF-band. The goal is to accomplish this with as few components as possible, thus cutting down the size and the production cost. An SDR solution means that the sampling of the signal is done as close to the antenna as possible. The wide bandwidth needed in such a product is achieved by using SP Devices algorithm for time-interleaved ADCs. Two hardware prototypes and two versions of the software were designed and implemented using this technology. They were also analyzed within this thesis work. The results proved to be good, and the possibilities to produce a commercial software-defined radio receiver for the VHF-band are good. / Syftet med det här examensarbetet är att utreda möjligheten att bygga en mjukvarustyrd radiomottagare (SDR) för VHF-bandet. Målet är att göra detta genom att använda så få komponenter som möjligt, och därigenom minska storleken och produktionskostnaden. En SDR lösning ger att samplingen kommer att ske så nära antennen som möjligt. Den stora bandbredd som behövs för en sådan produkt uppnås genom att använda SP Devices algoritm för att ''tidsinterleava'' höghastighets ADC:er. Två hårdvaruprototyper och två versioner av mjukvaran har designats och implementerats. Analyserna har visat bra resultat, och möjligheterna att bygga en komersiell mjukvarudefinierade radiomottagare för VHF-bandet ses som goda.

The paper focuses on the design and implementation of the base-band basic receiving functions, for a binary CP-FSK demodulator pilot study, as independent modules of a complete Reconfigurable Data-Link (RDL). A model-based approach and Software Defined Radio (SDR) paradigm are used for the design. The implementation will be executed on Field-Programmable Gate Array (FPGA) based hardware.

This dissertation starts by realizing that network management is a very complex and error-prone task. The major causes are identified through interviews and systematic analysis of network config- uration data on two large campus networks. This dissertation finds that network events and dynamic reactions to them should be programmatically encoded in the network control program by opera- tors, and some events should be automatically handled for them if the desired reaction is general. This dissertation presents two new solutions for managing and configuring networks using Software- Defined Networking (SDN) paradigm: Kinetic and Coronet. Kinetic is a programming language and central control platform that allows operators to implement traffic control application that reacts to various kinds of network events in a concise, intuitive way. The event-reaction logic is checked for correction before deployment to prevent misconfigurations. Coronet is a data-plane failure recovery service for arbitrary SDN control applications. Coronet pre-plans primary and backup routing paths for any given topology. Such pre-planning guarantees that Coronet can perform fast recovery when there is failure. Multiple techniques are used to ensure that the solution scales to large networks with more than 100 switches. Performance and usability evaluations show that both solutions are feasible and are great alternative solutions to current mechanisms to reduce misconfigurations.

Το ραδιόφωνο είναι από τις πλέον διαδεδομένες μορφές εκπομπής δεδομένων, χρησιμοποιείται δε ακόμα και σήμερα, σε μια εποχή που οι ψηφιακές τηλεπικοινωνίες επεκτείνονται ταχύτατα. Αρχικά επέτρεπε την μετάδοση μόνο ενός καναλιού ήχου, όμως επεκτάθηκε σε στερεοφωνική (δικάναλη) εκπομπή, προσετέθησαν μέθοδοι μετάδοσης ψηφιακών πληροφοριών (RDS/RBDS, DirectBand) για την πληροφόρηση χρηστών αλλά και για μεγαλύτερη ευελιξία των δεκτών. Παράδειγμα του τελευταίου είναι η λειτουργία "AF" (εναλλακτικές συχνότητες, alternative frequencies) η οποία δίνει την δυνατότητα σε ένα δέκτη να μεταπηδήσει σε άλλη συχνότητα στην οποία εκπέμπει ο ίδιος σταθμός αλλά με ισχυρότερο ή καθαρότερο σήμα. Δεδομένου του εύρους των λειτουργιών που χρησιμοποιούνται στις ραδιοφωνικές εκπομπές, είναι πολύ καλή επιλογή για την ανάπτυξη προγραμμάτων που τις εκμεταλλεύονται, από απλές μέχρι περίπλοκες τόσο στο αναλογικό όσο και στο ψηφιακό τμήμα. Για το αναλογικό τμήμα, στο ένα άκρο έχουμε έναν απλό μονοφωνικό δέκτη ενώ στο άλλο άκρο έναν στερεοφωνικό δέκτη ο οποίος μετρώντας την καθαρότητα του λαμβανόμενου σήματος επιλέγει το ποσοστό χρήσης στερεοφωνίας ώστε να επιτύχει συμβιβασμό μεταξύ διαχωρισμού καναλιών (στερεοφωνικής εικόνας) και χαμηλού θορύβου. Στα πλαίσια της παρούσας διπλωματικής, αναπτύχθηκε πρόγραμμα σε γλώσσα C το οποίο εκτελεί λειτουργία δέκτη ραδιοφωνικού σήματος διαμορφωμένου αναλογικά κατά συχνότητα (FM radio). Στον προγραμματισμό χρησιμοποιήθηκαν τεχνικές Software Defined Radio (SDR). Επιπλέον, το πρόγραμμα εκτελεί λήψη ψηφιακού σήματος ραδιοφωνικών πληροφοριών (Radio Broadcast Data System, RBDS/RDS). Στόχος της διπλωματικής είναι η επίδειξη της εφαρμογής τεχνικών SDR στα πλαίσια της υλοποίησης τηλεπικοινωνιακών συστημάτων. Με την αύξηση της ανάγκης της βιομηχανίας αλλά και των χρηστών για ταχύτερη μετάδοση δεδομένων, επήλθε και αύξηση της περιπλοκότητας των μεθόδων διαμόρφωσης στα τηλεπικοινωνιακά συστήματα. Η περιπλοκότητα αυτή απαιτεί χρήση αλγορίθμων που είναι αδύνατη με συστήματα με διακριτά στοιχεία. Μία λύση στο πρόβλημα αυτό είναι η αξιοποίηση σύγχρονων μικροεπεξεργαστών, των οποίων η ισχύς, ειδικά αυτή των εξειδικευμένων σε DSP, έχει γνωρίσει αλματώδη εξέλιξη. Προκειμένου να καταστεί δυνατή η αξιοποίηση του κατάλληλου υλικού για τα τηλεπικοινωνιακά συστήματα, χρειάζεται κατάλληλη μέθοδος προγραμματισμού. Η ιδέα αυτή έχει ήδη χρησιμοποιηθεί σε εμπορικά συστήματα. Ένα παράδειγμα είναι modem κοινής τηλεφωνικής γραμμής (PSTN/POTS) για οικιακούς υπολογιστές που το μεγαλύτερο μέρος της αποδιαμόρφωσης και διαμόρφωσης το εκτελούσε η κεντρική μονάδα επεξεργασίας του υπολογιστή. Συνεπώς, υπάρχουν παραδείγματα εφαρμογής αυτής της τεχνικής με ήδη υπαρκτό υλικό, δεν απαιτείται εξειδικευμένο hardware. Η εξέλιξη της ιδέας και η ευκολότερη πρόσβαση σε υλικό κατάλληλο, οδήγησε στην ανάπτυξη του Software Defined Radio. Software Defined Radio είναι ένα σύστημα ασύρματης τηλέπικοινωνίας (αν και είναι απολύτως εφικτή και η εφαρμογή σε ενσύρματα συστήματα) όπου αλγόριθμοι και μέρη του συστήματος που τυπικά υλοποιούνταν με ηλεκτρονικά στοιχεία (πυκνωτές, αντιστάτες, κ.α.) πραγματοποιούνται με προγράμματα που εκτελούνται σε σύστημα με επεξεργαστή, μικροελεγκτή ή άλλο προγραμματιζόμενο σύστημα. Η ονομασία Software Defined Radio αναφέρεται, επίσης, στο πρόγραμμα που εκτελεί το ανωτέρω σύστημα. Σε αυτά τα προγράμματα, χρησιμοποιούνται κατά κύριο λόγο τεχνικές επεξεργασίας ψηφιακού σήματος (DSP). Ως παράδειγμα προς μελέτη της τεχνικής θα χρησιμοποιήσουμε ένα από τα πλέον γνωστά πρωτόκολλα, το οποίο δεν είναι τετριμμένο και χρησιμοποιείται ευρύτατα και στη σύγχρονη εποχή, το ραδιόφωνο FM. Το πρωτόκολλο FM είναι αρκετά απλό ώστε η ανάλυσή του να είναι προσβάσιμη χωρίς να απαιτεί εξειδικευμένες γνώσεις τηλεπικοινωνιακών συστημάτων, αλλά όχι τετριμμένο, ώστε να αναδεικνύει την χρησιμότητα της τεχνικής SDR. Ένας δεύτερος λόγος για αυτή την επιλογή είναι η ταυτόχρονη εκπομπή ψηφιακής πληροφορίας από τους σταθμούς. Η λήψη αυτών των πληροφοριών με τη χρήση SDR υπογραμμίζει την ευελιξία της τεχνικής, η οποία επιτρέπει τον ταυτόχρονο χειρισμό τόσο των αναλογικών πληροφοριών (ήχου, στη συγκεκριμένη περίπτωση) όσο και των ψηφιακών πληροφοριών (RBDS/RDS) από το ίδιο πρόγραμμα. Στο Κεφάλαιο 1 περιγράφεται η αρχή λειτουργίας της αναλογικής διαμόρφωσης κατά συχνότητα καθώς και η εφαρμογή της στη ραδιοφωνία. Ορίζονται οι σχετικές παράμετροι και καθορίζονται οι τιμές που λαμβάνουν στην κοινή ραδιοφωνία FM. Τέλος, περιγράφεται η μετάδοση ψηφιακών πληροφοριών με το πρωτόκολλο RDS. Στο Κεφάλαιο 2 περιγράφεται η δομή και λειτουργία ενός δέκτη FM με διακριτά στοιχεία. Αναλύεται η αρχή λειτουργίας του δέκτη, ονομάζονται μερικά από τα στοιχεία που χρησιμοποιούνται συνήθως και διαγράφονται βασικές ομοιότητες με τους δέκτες SDR. Στο Κεφάλαιο 3 περιγράφεται η αρχή λειτουργίας του SDR. Δίνονται παραδείγματα υλικού κατάλληλου για SDR και οι δυνατότητες που απαιτούνται. Δίνονται παραδείγματα λογισμικού κατάλληλου για SDR και παραδείγματα εφαρμογών του. Στο Κεφάλαιο 4 αναλύεται το υλικό που χρησιμοποιήθηκε και το πρόγραμμα που αναπτύχθηκε για την αποδιαμόρφωση σήματος FM και αποκωδικοποίηση σήματος RDS. Επίσης περιγράφεται το υλικό που χρησιμοποιήθηκε καθώς και τα κριτήρια επιλογής τους. Ορίζονται οι είσοδοι και έξοδοι του προγράμματος και περιγράφεται η δομή του. Αναλύεται η λειτουργία των επιμέρους στοιχείων του προγράμματος που αναπτύχθηκε και μελετάται η συμπεριφορά τους. Τέλος, αναλύεται η αποδιαμόρφωση και αποκωδικοποίηση του ψηφιακού σήματος (RDS) από το πρόγραμμα. Στα παραρτήματα δίδονται οι συντελεστές των ψηφιακών φίλτρων που χρησιμοποιήθηκαν στην ανάπτυξη του δέκτη, ο πλήρης κώδικας του δέκτη και οδηγίες για την δημιουργία φασματογραφημάτων με το MATLAB. / FM radio is one of the most widespread forms of data transmission, used even today, in an era where digital telecommunications are quickly spreading. Initially, it allowed transmission of only one audio channel, but it was extended to stereo (two channel) transmission, digital information methods of transmission were added (RDS/RBDS, DirectBand) for user information and for greater receiver versatility. One example of the latter is the AF ("alternative frequencies") functionality which allows a receiver to switch over to another frequency, carrying the same radio program but with better reception. Given the great width of functions that are used in radio transmissions, it is a very good choice for developing software that take advantage of them, from simple to complex, both in the analog and digital domain. For the analog domain, on one end, there may be a simple monophonic receiver and on the other end a stereo receiver which, according to the clarity of the received signal, can adjust the level of stereo separation to achieve a preferable compromise between stereo image and low noise audio. For the purposes of this project, a software program was written, in C, which functions as a frequency modulated, analog radio signal receiver (FM radio). Software Defined Radio techniques were used while developing this program. Additionally, the program performs RDS ("radio data system") signal reception. The objective of this project is to demonstrate the use of Software Defined Radio techniques in the development of telecommunication systems. The industry's, and the users', need for faster data transmission, brought an increase in modulation method complexity in telecommunication systems. This complexity requires use of algorithms that is impossible with systems with discrete components. One solution to this problem is via utilization of modern microprocessors, especially those specializing in DSP, the performance of which has increased dramatically. In order to be able to use the appropriate hardware in a telecommunication system using SDR, an appropriate method of programming them is necessary. This idea has been already used in commercial systems. One example are modems for the common copper telephone line (PSTN /POTS) for home computers, where most of the modulation and demodulation was performed by the computers central processor. Therefore, there are examples of applications of this method using common hardware. The evolution of this idea and the easier access to necessary hardware led to the development of Software Defined Radio. Software Defined Radio is a wireless telecommunication system (although a wired system is equally feasible) where algorithms and components that would, typically, be implemented with electronic elements (capacitors, resistors, etc) are realized with a software program running on a system with a microprocessor, microcontroller or other programmable device. The name Software Defined Radio is also used to refer to the program itself. In such a program, DSP techniques are commonly used. As an example for studying this method we are using one of the most widely known protocols, one that is not trivial and is widely used even in modern times, the FM radio. The FM protocol is simple enough so that its analysis is approachable without specialized knowledge of telecommunication systems, but not trivial, so that it demonstrates the usefulness of the SDR method. Another reason for this choice is the simultaneous transmission of digital information from an FM broadcast station. Reception of this signal, by the program, underlines the versatility of SDR, which allows simultaneous handling of both analog (audio, in this case) and digital (RDS) information. The first chapter presents the principle of operation of analog frequency modulation and its application in radio broadcasting. The respective parameters are defined and specific values for common FM radio broadcasting are given. Finally, digital data transmission via the RDS protocol is described. The second chapter presents the structure and functionality of an FM receiver implemented with discrete elements. Its principle of operation is analyzed, some of the more common elements used are named and similarities with SDR receivers are drawn. The third chapter presents the principle of operation of an SDR system. Examples of useful hardware and relevant requirements are given. Finally, examples of suitable software and respective applications are given. The fourth chapter presents an analysis of the hardware that was used and the software program that was developed for the demodulation of the FM signal and decoding of the RDS signal, along with the criteria for choosing them. The program structure is described and its input and output data signal formats are defined. The functionality of each component of the software program is analyzed and its behavior is studied. Finally, the demodulation and decoding process for the RDS signal by the program is analyzed. In the appendixes, the coefficients of the digital filters are listed, along with the full source code for the software program that was developed and, finally, a guide for creating spectral graphs with MATLAB, similar to those in section 4.3.2.

Currently, networks and networked systems are essential media for us to communicate with other people, access resources, and share information. Reading (or sending) emails, navigating web sites, and uploading pictures to social medias are common behaviors using networks. Besides these, networks and networked systems are used to store or access sensitive or private information. In addition, major economic activities, such as buying food and selling used cars, can also be operated with networks. Likewise, we live with networks and networked systems. As network usages are increasing and popular, people face the problems of net- work attacks. Attackers on the networks can steal people’s private information, mislead people to pay money for fake products, and threaten people, who operate online commercial sites, by bothering their services. There are much more diverse types of network attacks that torture many people using networks, and the situation is still serious. The proposal in this dissertation starts from the following two research questions: (i) what kind of network attack is prevalent and how we can investigate it and (ii) how we can protect our networks and networked systems from these attacks. Therefore, this dissertation spans two main areas to provide answers for each question. First, we analyze the behaviors and characteristics of large-scale bot infected hosts, and it provides us new findings of network malware and new insights that are useful to detect (or defeat) recent network threats. To do this, we investigate the characteristics of victims infected by recent popular botnet - Conficker, MegaD, and Srizbi. In addition, we propose a method to detect these bots by correlating network and host features. Second, we suggest new frameworks to make our networks secure based on the new network technology of Software Defined Networking (SDN). Currently, SDN technology is considered as a future major network trend, and it can dynamically program networks as we want. Our suggested frameworks for SDN can be used to devise network security applications easily, and we also provide an approach to make SDN technology secure.

Research indicates that multiprocessor-based architectures will provide a flexible alternative to hard-wired application-specific integrated circuits (ASICs) suitable to implement the multitude of wireless standards required by mobile devices, while meeting their strict area and power requirements. This shift in design philosophy has led to the software-defined radio (SDR) paradigm, where a significant portion of a wireless standard's physical layer is implemented in software, allowing multiple standards to share a common architecture. Turbo codes offer excellent error-correcting performance, however, turbo decoders are one of the most computationally complex baseband tasks of a wireless receiver. Next generation wireless standards such as Worldwide Interoperability for Microwave Access (WiMAX), support enhanced double-binary turbo codes, which offer even better performance than the original binary turbo codes, at the expense of additional complexity. Hence, the design of efficient double-binary turbo decoder software is required to support wireless standards in a SDR environment. This thesis describes the optimization, parallelization, and simulated performance of a software double-binary turbo decoder implementation supporting the WiMAX standard suitable for SDR. An adapted turbo decoder is implemented in the C language, and numerous software optimizations are applied to reduce its overall computationally complexity. Evaluation of the software optimizations demonstrated a combined improvement of at least 270% for serial execution, while maintaining good bit-error rate (BER) performance. Using a customized multiprocessor simulator, special instruction support is implemented to speed up commonly performed turbo decoder operations, and is shown to improve decoder performance by 29% to 40%. The development of a flexible parallel decoding algorithm is detailed, with multiprocessor simulations demonstrating a speedup of 10.8 using twelve processors, while maintaining good parallel efficiency (above 89%). A linear-log-MAP decoder implementation using four iterations was shown to have 90% greater throughput than a max-log-MAP decoder implementation using eight iterations, with comparable BER performance. Simulation also shows that multiprocessor cache effects do not have a significant impact on parallel execution times. An initial investigation into the use of vector processing to further enhance performance of the parallel decoder software reveals promising results. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-09-25 16:22:47.288

Software defined networking (SDN) is a relatively new paradigm that decouples individual network elements from the control logic, offering real-time network programmability, translating high level policy abstractions into low level device configurations. The framework comprises of the data (forwarding) plane incorporating network devices, while the control logic and network services reside in the control and application planes respectively. Operators can optimize the network fabric to yield performance gains for individual applications and services utilizing flow metering and application-awareness, the default traffic management method in SDN. Existing approaches to traffic optimization, however, do not explicitly consider user application trends. Recent SDN traffic engineering designs either offer improvements for typical time-critical applications or focus on devising monitoring solutions aimed at measuring performance metrics of the respective services. The performance caveats of isolated service differentiation on the end users may be substantial considering the growth in Internet and network applications on offer and the resulting diversity in user activities. Application-level flow metering schemes therefore, fall short of fully exploiting the real-time network provisioning capability offered by SDN instead relying on rather static traffic control primitives frequent in legacy networking. For individual users, SDN may lead to substantial improvements if the framework allows operators to allocate resources while accounting for a user-centric mix of applications. This thesis explores the user traffic application trends in different network environments and proposes a novel user traffic profiling framework to aid the SDN control plane (controller) in accurately configuring network elements for a broad spectrum of users without impeding specific application requirements. This thesis starts with a critical review of existing traffic engineering solutions in SDN and highlights recent and ongoing work in network optimization studies. Predominant existing segregated application policy based controls in SDN do not consider the cost of isolated application gains on parallel SDN services and resulting consequence for users having varying application usage. Therefore, attention is given to investigating techniques which may capture the user behaviour for possible integration in SDN traffic controls. To this end, profiling of user application traffic trends is identified as a technique which may offer insight into the inherent diversity in user activities and offer possible incorporation in SDN based traffic engineering. A series of subsequent user traffic profiling studies are carried out in this regard employing network flow statistics collected from residential and enterprise network environments. Utilizing machine learning techniques including the prominent unsupervised k-means cluster analysis, user generated traffic flows are cluster analysed and the derived profiles in each networking environment are benchmarked for stability before integration in SDN control solutions. In parallel, a novel flow-based traffic classifier is designed to yield high accuracy in identifying user application flows and the traffic profiling mechanism is automated. The core functions of the novel user-centric traffic engineering solution are validated by the implementation of traffic profiling based SDN network control applications in residential, data center and campus based SDN environments. A series of simulations highlighting varying traffic conditions and profile based policy controls are designed and evaluated in each network setting using the traffic profiles derived from realistic environments to demonstrate the effectiveness of the traffic management solution. The overall network performance metrics per profile show substantive gains, proportional to operator defined user profile prioritization policies despite high traffic load conditions. The proposed user-centric SDN traffic engineering framework therefore, dynamically provisions data plane resources among different user traffic classes (profiles), capturing user behaviour to define and implement network policy controls, going beyond isolated application management.