With its enormous potential Voice over Internet Protocol is one of the latest buzzwords in information technology. Despite the numerous advantages of Voice over IP, it is a major technical challenge to achieve a similar call quality as experienced in the ordinary Public Switched Telephone Network. This thesis introduces standardized Internet protocols for Voice over IP, such as Session Initiation Protocol (SIP), Real-time Transport Protocol (RTP), in its background chapter. In order to provide better Quality of Service (QoS) Voice over IP applications should support a feedback mechanism, such as the Real-time Control Protocol (RTCP), and use accurate timing information, provided by the Network Time Protocol (NTP). Additionally this thesis considers synchronization issues in calls with two and more peers. After a rather academic overview of Voice over IP, the open source real-time application “minisip”, a SIP user agent, and its operation and structure for handling audio streams will be introduced. Minisip was extended by an implementation of NTP and RTCP to provide a test platform for this thesis. A clear conclusion is that the addition of global time helps facilitate synchronization of multiple streams from clients located any where in the network and in addition the ability to make one-way delay measurements helps SIP user agents to provide better quality audio to their users. / Röst över IP, eller Internettelefoni baserad på “Voice over Internet Protocol” (VoIP), har med sin stora potential blivit ett av de senaste modeorden inom informationsteknologin. Vid sedan av ett antal fördelar med VoIP så innebär det en stor teknisk utmaning att uppnå en likadan samtalskvalitet som i det vanliga, fasta, telenätet. I den här uppsatsen beskrivs hur tjänstevalitet för VoIP kan förbättras genom att noggrant tidssynkronisera de (två eller flera) klienter som deltar i ett telefonsamtal. För detta krävs dels en återkopplingsmekanism, såsom “Real-time Control Protocol” (RTCP), samt en gemensam tidsuppfattning i de inblandade klienterna, vilket kan uppnås med hjälp av “Network Time Protocol” (NTP). Dessa protokoll, liksom de övriga Internet-standarder som VoIP baseras på (såsom “Session Initiation Protocol” (SIP) och “Real-time Transport Protocol” (RTP), beskrivs inledningsvis i uppsatsen. För studien har en SIP-klient baserad på öppen källkod använts (“Minisip”), och utökats med NTP och RCTP funktionalitet för att testa den föreslagna förbättringen av VoIP. En tydlig slutsats är att kännedom om en “global tid” möjliggör synkronisering av multipla ljudströmmar från klienter som befinner sig på olika nätverk. Möjligheten att mäta paketfördröjningen (envägs) bidrar också till en förbättrad ljudkvalitet.

As the coverage of modern wireless technologies expands, today’s mobile phones and PDAs often have a range of heterogeneous networks to which they may connect. It would benefit mobile applications to use the network which best corresponds to its need. However, making the handovers between networks transparent to allow communication sessions to survive is not trivial as the TCP/IP suite, used by most networking applications today, was initially not designed with mobility in mind. A Vinnova founded research project at Saab (together with associates1) has found that it could prove advantageous to monitor network quality together with the application’s needs and make intelligent decisions regarding what network to use. An algorithm for network classification and evaluation has been proposed. This thesis examined prerequisites and methods for implementing adaptive network connectivity through transparent handovers for mobile devices, resulting in a tentative model to demonstrate the mentioned research results. The prototype, implemented as a user space middleware, utilizes UDP encapsulation and a per-packet basis link evaluation, resulting in small overhead and fast context adaptation. Link monitoring ensures that server and clients are constantly updated about network quality and availability. The prototype yielded transparent handovers between networks, with short handover delays, at the cost of reduced performance for fast networks. 1 Blekinge Institute of Technology, Swedish National Testing and Research Institute, and SwedishRoad Administration / Täckningen av trådlösa nätverk ökar konstant, och dagens mobiltelefoner och handdatorer har ofta ett antal olika nätverk de kan ansluta till. Det skulle vara fördelaktigt för mobila applikationer att använda det nätverk som bäst passar dess behov. Att göra övergångarna mellan dessa nätverk transparenta så att pågående kommmunikationssessioner kan fortgå är dock inte helt trivialt, då TCP/IP protokollen från början inte var tänkta för mobila enheter. Ett av Vinnova finansierat forskningsprojekt utfört på Saab med flera1 har undersökt möjligheterna att övervaka kvaliteten på olika trådlösa nätverk samt kraven från applikationerna, och med detta som grund utföra intelligenta beslut om vilket nätverk som ska utnyttjas. En algoritm för att utföra dessa beslut har också föreslagits. Detta examensarbete undersökte möjligheterna för att implementera adaptiv nätverksroaming genom transparenta övergångar för mobila enheter, och resulterade i en demonstrator, som även kan visa resultaten från den nämnda forskningen. Prototypen, implementerad som en "middleware", använder UDP tunnling och en per-paket nätverksutvärdering, vilket resulterade i liten overhead och snabb anpassning till nya kommunikationssituationer. En länkövervakare såg till att server och klienter alltid var uppdaterade om kvaliteten och tillgängligheten av olika nätverk. Prototypen gav totalt transparenta övergångar mellan nätverk med relativt korta fördröjningar, med nackdelen av viss reducerad prestanda för snabba nätverk. 1 Blekinges Tekniska Högskola, Sveriges Provnings – och Forskningsinstitut, samt Vägverket

The focus of this thesis is on transferring data between mobile devices. It analyzes the resource consumption of using the Wireless LAN interface in some situations, and proposes and evaluates some new applications involving the transfer of voice and data files. Measurements show the high consumption of battery power due to the operation of a wireless network interface, even if it is not “actively” used to transfer data, while the memory consumption of the running applications is very limited. This thesis includes also an application to transfer files between two or more Pocket PCs: it is proposed as an addition to the VoIP application Minisip. Finally I have developed an application in order to explore the possibility to make a voice call by transferring real-time encoded text using UDP and/or RTP streams. This could be used together with speech-to-text and text-to-speech conversion applications at the end points to allow a “voice conversation” even on wireless links with very limited capacity, whereas a standard VoIP conversation would not be affordable. / Fokus i detta examensarbete ligger på överföring av data mellan mobila enheter. Det analyserar resursutnyttjandet vid användande av Wireless LAN-anslutning i några situationer, samt brukar analysen för att föreslå och utvärdera ett antal nya applikationer för överföring av röstsamtal och filer. Mätningar visar den höga konsumtion av batterikraft som anslutning till ett trådlöst nätverk gränsnitt, även då det inte används "aktivt" för dataöverföring, medan de applikationer som använts här behöver bara mycket begränsad minneskapacitet. I detta examensarbete ingår även ett program för överföring av filer mellan två eller flera mobila apparater, föreslaget att ingå i Minisip, en VoIP applikation. Dessutom föreslås och utvärderas en applikation som undersöker möjligheterna att vid röstsamtal överföra realtidskodad text via RTP och/eller UDP stream. Använd tillsammans med en röst-till-text- och text-till-röstomvandling i ändpunkterna möjliggör denna genomförande av röstsamtal även då mycket begränsade trådlösa anslutningar nyttjas. / <p>Exchange student from Pisa.</p>

Voice over IP (VoIP) can be defined as the ability to make phone calls and to send faxes (i.e., to do everything we can do today with the Public Switched Telephone Network, PSTN) over IP−based data networks with a suitable quality of service and potentially a superior cost/benefit ratio. There is a desire to provide (VoIP) with the suitable security without effecting the performance of this technology. This becomes even more important when VoIP utilizes wireless technologies as the data networks (such as Wireless Local Area Networks, WLAN), given the bandwidth and other constraints of wireless environments, and the data processing costs of the security mechanisms. As for many other (secure) applications, we should consider the security in Mobile VoIP as a chain, where every link, from the secure establishment to the secure termination of a call, must be secure in order to maintain the security of the entire process. This document presents a solution to these issues, providing a secure model for Mobile VoIP that minimizes the processing costs and the bandwidth consumption. This is mainly achieved by making use of high− throughput, low packet expansion security protocols (such as the Secure Real−Time Protocol, SRTP); and high−speed encryption algorithms (such as the Advanced Encryption Standard, AES). In the thesis I describe in detail the problem and its alternative solutions. I also describe in detail the selected solution and the protocols and mechanisms this solution utilizes, such as the Transport Layer Security (TLS) for securing the Session Initiation Protocol (SIP), the Real−Time Protocol (RTP) profile Secure Real−Time Protocol (SRTP) for securing the media data transport , and the Multimedia Internet KEYing (MIKEY) as the key−management protocol. Moreover, an implementation of SRTP, called MINIsrtp, is also provided. The oral presentation will provide an overview of these topics, with an in depth examination of those parts which were the most significant or unexpectedly difficult. Regarding my implementation, evaluation, and testing of the model, this project in mainly focused on the security for the media stream (SRTP). However, thorough theoretical work has also been performed and will be presented, which includes other aspects, such as the establishment and termination of the call (using SIP) and the key−management protocol (MIKEY). / Voice over IP (VoIP) kan defineras som förmågan att göra ett telefonsamtal och att skicka fax (eller att göraallting som man idag kan göra över det publika telefonnätet) över ett IP−baserat nätverk med en passande kvalitet och till lägre kostnad, alternativt större nytta. VoIP måste tillhandahållas med nödvändiga säkerhetstjänster utan att teknikens prestanta påverkas. Detta blir allt viktigare när VoIP används över trådlösa länktekniker (såsom trådlösa lokala nätverk, WLAN), givet dessa länkars begränsade bandbredd och den bearbetningkraft som krävs för att exekvera säkerhetsmekanismerna. Vi måste tänka på VoIPs säkerhet likt en kedja där inte någon länk, från säker uppkoppling till säker nedkoppling, får fallera för att erhålla en säker process. I detta dokument presenteras en lösning på detta problem och innefattar en säker modell för Mobile VoIP som minimerar bearbetningskostnaderna och bandbreddsutnyttjandet. Detta erhålls huvudsakligen genom utnyttjande av säkerhetsprotokoll med hög genomströmning och låg paketexpansion, såsom "Secure Real− time Protocol" (SRTP), och av krypteringsprotokoll med hög hastighet, såsom "Advanced Encryption Standard" (AES). I detta dokument beskriver jag problemet och dess alternativa lösningar. Jag beskriver också den valda lösningen och dess protokoll och mekanismer mer detaljerat, till exempel "Transport Layer Security" (TLS) för att säkra "Session Initiation Protocol" (SIP), SRTP för att skydda transporten av data och "Multimedia Internet KEYing" (MIKEY) för nyckelhantering. En implementation av SRTP, kallad MINIsrtp, finns också beskriven. Beträffande praktiskt arbete och tester av lösningsmodellen har detta projekt fokuserats på skyddandet av datatransporten (SRTP), dess implementation och prestanda. Emellertid har en grundlig teoretisk undersökning genomförts, vilken innefattar andra aspekter såsom telefonsamtalets uppkoppling och nedkoppling (med hjälp av SIP) och valet av passande nyckelhanteringsprotokoll (MIKEY) för att stödja SRTP.

Productivity for digital circuit design is being outpaced currently by the rate at which<br />silicon is growing such as FPGAs. Complex designs take a large amount of engineering<br />hours to complete. Reuse of existing design can potentially decrease this cost and increase<br />design productivity. However, existing digital hardware designs are not being effectively<br />reused by the hardware community due to the inability of designers to have knowledge of<br />all the attributes of designs that can be reused. In addition, designers will have to accustom<br />themselves to designs in the hardware library. By having a back-end system that looks for<br />similar circuits, there is little to no effort for the designer to reuse the design. This thesis<br />provides an overview and comparison of different methods for characterizing and comparing<br />digital circuits in order to suggest candidate circuits that engineers can reuse. Several of<br />these methods are implemented, modified, and compared to show the feasibility of utilizing<br />this work for increasing overall productivity.<br /> / Master of Science

Wireless sensor networks are composed of large numbers-up to thousands-of tiny radio-equipped sensors. Every sensor has a small microprocessor with enough power to allow the sensors to autonomously form networks through which sensor information is gathered. Wireless sensor networks makes it possible to monitor places like nuclear disaster areas or volcano craters without requiring humans to be immediately present. Many wireless sensor network applications cannot be performed in isolation; the sensor network must somehow be connected to monitoring and controlling entities. This thesis investigates a novel approach for connecting sensor networks to existing networks: by using the TCP/IP protocol suite in the sensor network, the sensors can be directly connected to an outside network without the need for special proxy servers or protocol converters. Bringing TCP/IP to wireless sensor networks is a challenging task, however. First, because of their limited physical size and low cost, sensors are severely constrained in terms of memory and processing power. Traditionally, these constraints have been considered too limiting for a sensor to be able to use the TCP/IP protocols. In this thesis, I show that even tiny sensors can communicate using TCP/IP. Second, the harsh communication conditions make TCP/IP perform poorly in terms of both throughput and energy efficiency. With this thesis, I suggest a number of optimizations that are intended to increase the performance of TCP/IP for sensor networks. The results of the work presented in this thesis has had a significant impact on the embedded TCP/IP networking community. The software developed as part of the thesis has become widely known in the community. The software is mentioned in books on embedded systems and networking, is used in academic courses on embedded systems, is the focus of articles in professional magazines, is incorporated in embedded operating systems, and is used in a large number of embedded devices. / Contiki / uIP

Im Rahmen der vorliegenden Dissertation wurden die cDNAs der Hauptmyelinproteine IP2 und 36K aus dem ZNS der Regenbogenforelle isoliert, vervollständigt, molekularbiologisch charakterisiert und in verschiedenen Systemen heterolog exprimiert. Für das 36K Protein konnte eine Methode zur Proten-Aufreinigung etabliert werden. Für das IP-Protein konnte ein mimetisches Zellystem aufgebaut werden, welches erste experimentelle Hinweise auf eine Funktion als Adhäsionsmolekül der Myelinscheide ermöglichte. Die vorliegende Arbeit liefert den Grundstein für weiterführende Arbeiten auf dem Gebiet der Myelinproteine.

Internet est le résultat de l’interaction des milliers de réseaux qui le composent. On les appelle les systèmes autonomes, chacun est identifié par un numéro unique (ASN). Les politiques de routage des AS et les accords économiques restent confidentiels normalement. Afin de mieux comprendre le routage dans l’Internet, les chercheurs modèlent le routage. Le model souvent utilisé c’est la représentation d’un AS par un atome. Nous présentons trois contributions dans ce travail. On montre d’abord des contradictions entre les décisions de routage réellement faites et les inférences à partir d’un ensemble d’hypothèses souvent utilisées. 70% des instances de ce qu’on appelle «plusieurs sorties» montrent des incohérences. Le routage est appelé à plusieurs sorties quand un AS utilise simultanément plusieurs routes vers la même destination, et chacune passe par un AS différent. Notre deuxième contribution est sur les routes BGP erronées causées par des mauvaises configurations liées à la transaction de la représentation des ASNs de 16-bits à 32-bits et l’utilisation d’AS23456 pour assurer la compatibilité. Nous montrons que tels erreurs sont encore présentes, ensuite nous montrons les effets des routes qui contiennent AS23456 sur les travaux qui emploient ces routes. Notre dernière contribution concerne les dynamiques de de routage dans l’Internet. Nous proposons une méthode pour quantifier ces dynamiques dans chaque AS afin d’en extraire ceux les plus dynamiques. Ensuite, on se concentre sur l’AS Level 3, l’AS le plus dynamique. Nous expliquons que la raison pour ce grand nombre de dynamique c’est l’équilibration de charge entre des routeurs qui avait plusieurs liens physiques. / Internet is the result of interaction of the thousands of networks that compose it. Each of them is called an autonomous system (AS) and has a unique number (ASN). Routing policies of ASes and business agreements remain in most cases confidential. To understand Internet routing, researchers use routing models. A large family of models represents an AS as an atomic structure. We make in this work three contributions. We look first on a set of commonly made assumptions to show using what we call multi-exit routing contradictions in routing decisions between real routing observed in publicly available measurements and that inferred from the assumptions. Sometimes, more than 70% of multi-exit instances show incoherencies. Multi-exit routing happens when an AS uses simultaneously different routes to a destination, each passing through a different AS. Our second contribution concerns erroneous BGP routes due to misconfigurations in BGP routers related to AS_TRANS, the solution introduced to assure the compatibility with old BGP routers when the change was made to represent ASNs on 32-bits instead of 16-bits. We show that such errors are indeed present, then we show how they can affect work making use of routes carrying this ASN. Our last contribution concerns routing dynamics in the Internet. We propose a method to quantity routing dynamics in each AS, then we look on ASes that have a large proportion of dynamics. After that, we focus on the AS Level 3, one of the ASes that we observe to be most dynamic. We explain that one of the reasons of a large part of the observed dynamics is load balancing between routers that have multiple physical links between each of them.

Dans cette thèse, nous concevons trois nouveaux mécanismes d'authentification basés sur l'identité des utilisateurs. Par conséquent, nous apportons des améliorations sur le contrôle d'accès à différents types de réseaux tels que les réseaux domestiques, les réseaux gouvernementaux et les réseaux cellulaires. L'identité se base sur des gabarits biométriques publics, des chaînes de caractères simples comme l’adresses e-mail ou l’identifiant (login). La première solution concerne l'utilisation de données biométriques dans les mécanismes d'authentification des réseaux domestiques (Home Network HN). Nous voulons personnaliser l'accès de chaque utilisateur dans le HN et prévenir les utilisateurs illégitimes (en passant par la passerelle domestique « Home Gateway (HG) ») d'avoir accès aux services. Nous proposons une nouvelle méthode d'authentification biométrique qui respecte la contrainte de ne pas sauvegarder les données biométriques (Biometric Template (BT)) des utilisateurs dans le HG. Pour satisfaire cette contrainte, nous proposons d'utiliser la méthode de « Fuzzy Vault » pour cacher un secret utilisé pour l'authentification. Un logiciel génère une identité biométrique révocable (BioID) en utilisant une transformation fonctionnelle. Ce BioID est utilisé par le mécanisme du fuzzy vault pour cacher une clé de session secrète. La deuxième solution propose des mécanismes d'authentification pour les passeports biométriques (e-Passeports). Les paramètres de chiffrement sont générés en utilisant les données biométriques et, ainsi, ils seront personnalisés pour l'utilisateur. Notre proposition introduit un nouveau mécanisme d'authentification pour le passeport biométrique utilisant le protocole Diffie-Hellman de partage de clé basé sur les courbes elliptiques (ECDH). Ce protocole est nécessaire pour générer une clé de session utilisée pour authentifier le voyageur et le système d'inspection (IS) et ainsi sécuriser l'échange des données entre eux. Notre protocole peut utiliser les points "minuties" d'une empreinte digitale et le code de l'iris du détenteur du passeport électronique. Dans la troisième solution, nous avons travaillé sur le réseau cellulaire et nous avons utilisé une chaîne de caractères simple (l’adresse e-mail de l’utilisateur) comme identifiant pour accéder aux services. Nous avons choisi l'IP Multimedia Subsystem (IMS) qui est une architecture de recouvrement pour la fourniture de services multimédia, comme support. Nous avons conçu un nouveau mécanisme d'authentification aux services en utilisant la cryptographie basée sur l'identité (IBC). L'objectif était d'authentifier les utilisateurs en utilisant leurs identifiants public et privé pour surmonter les faiblesses connues du protocole «Authentication and Key Agreement (AKA) ». Nous nous sommes concentrés sur les tentatives d'écoute et d’usurpation d'identité qui peuvent avoir lieu dans le scénario classique de l’IMS et nous avons montré comment la solution proposée peut prévenir ces attaques. Nous avons ensuite proposé d'ajouter une vérification par lot au niveau du Bootstrapping Server Function (BSF) pour diminuer le délai de vérification des signatures et le temps de réponse de l’authentification. / In this thesis, we design three new authentication mechanisms based on user identity. Therefore, we bring improvements in access control for different classes of networks such as Home Network, Governmental Network and Cellular Network. The identity can be biometric public features, simple strings (email addresses, login...), etc. The first solution concerns the use of biometric in Home Network' authentication mechanisms. In the Home Network (HN) case study, we aim at personalizing the access of each user in the HN and preventing illegitimate users (passing by the Home Gateway (HG)) to have any access. We propose a new biometric authentication method which respects the constraint of the non storage of the users' Biometric Template (BT) in the HG. To satisfy this constraint, we propose using the fuzzy vault method to hide a secret that should be used for authentication. A software generates a revocable biometric identity (BioID) using a functional transformation. This BioID is used in the fuzzy vault mechanisms to hide a secret session key. The second solution proposes e-Passport authentication mechanisms. The cryptographic parameters are generated using the biometric templates and hence, personalized for the user. In travel document case study, we present our proposal which introduces a new e-Passport authentication mechanisms based on the Elliptic Curve Diffie-Hellman (ECDH) Key Agreement protocol. This protocol is needed to generate a session key used to authenticate the traveler and the Inspection System (IS) to exchange secure data. Our protocol is defined using minutiae data (fingerprint) and iris code of the e-Passport holder. In the third solution, we worked on the Cellular Network and we used a simple string, like email addresses, as identifier to access to services. We choose the IP Multimedia Subsystem (IMS) which is an overlay architecture for the provision of multimedia services. We design a new service authentication mechanism relying on Identity Based Cryptography (IBC) for the IMS architecture. The goal was to authenticate the users using their public and private identifiers to overcome known weaknesses in the Authentication and Key Agreement (AKA) protocol. We focused on the eavesdropping and impersonation attacks that can take place in classical IMS scenario and we showed how our proposed solution can prevent against these attacks. We, then, proposed to add a Batch Verification on the Bootstrapping Server Function (BSF) to decrease signature verification delay and the authentication response time.

The goal of the project was to create independent system, which is able to supervise remote site using Ethernet network. It can measure temperature and check state of door magnetic contact. Gained information are sent over network to the cenral node, which is able to present them on web page. In the project are also discussed important network protocols needed for implementation of the system, hardware used for implementation and software of the system.