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In this work, some network protocols with Wireshark Protokollanalyser should be observed and described the deal with them. Wireshark is an offshoot of "Ethereal", one of the most popular protocol analyzer. Wireshark analysis network traffic, draws on it and make it clear . For the simulation of the network is used VNUML. Since VNUML can only be used under Linux, andLinux is running as a virtual machine in between to work in Windows to be able to.
Dieses Dokument schlägt ein Konzept für eine Personal Key Infrastruktur in iCity vor. Über ein Trust Center (TC) ausgestellte Zertiffkate gewährleisten einen sicheren Schlüsselaustausch mit nachweisbarer Authentisierung des Kommunikationspartners, Abhörsicherheit sowie Unverf älschtheit und Nachweisbarkeit der Nachrichten. Das gemeinsam vertrauensw ürdige TC muss während der Kommunikation nicht erreichbar sein. Es erhält lediglich öffentliche Informationen. Das Konzept stellt mehrere Sicherheitsstufen vor, die sichere Identiffkation und Anonymität unterschiedlich gewichten.
This minor thesis shows a way to optimise a generated oracle to achieve shorter runtimes. Shorter runtimes of test cases allows the execution of more test cases in the same time. The execution of more test cases leads to a higher confidence in the software-quality. Oracles can be derived from specifications. However specifications are used for different purposes and therefore are not necessarily executable. Even if the are executable it might be with only a high runtime. Those two facts come mostly from the use of quantifiers in the logic. If the quantifier-range is not bounded, respectively if the bounds are outside the target language-datatype-limits, the specification is too expressive to be exported into a program. Even if the bounds inside the used datatype-limits, the quantification is represented as a loop which leads to a runtime blowup, especially if quantifiers are nested. This work explains four different possibilities to reduce the execution time of the oracle by manipulating the quantified formular whereas this approach is only applicable if the quantified variables are of type Integer.
So far VNUML (Virtual Network User Mode Linux) has been used by the group for Computer Networks at the University of Koblenz in such a way as to test its own protocol enhancement for RIP (Routing Information Protocol) on strengths and weaknesses. The modified version of RIP is called RMTI (RIP with minimal topology information). In particular, special test scenarios have been used to investigate wether a Count-to-Infinity (CTI) problem can be completely avoided and how quickly the network converges after the failure or breakdown of a router. Tius thesis investigates whether the MTI enhancement also provides for better performance in larger networks. Furthermore, it will be investigated if it is worth using the script tool EDIV ((spanish: Escenarios DIstribuidos con VNUML, english: Distributed Scenarios using VNUML) due to its enhanced scalability and whether the distribution of an XML scenario on several computers has a significant impact on the convergence time. Apart from simulations, test scenarios will be developed and tested in order to generate results about the efficiency and scalability of the Distance Vector Routing Protocol.
This thesis presents an analysis of API usage in a large corpus of Java software retrieved from the open source repositories hosted at SourceForge. Most larger software projects use software libraries, which offer a public "application programming interface" or API as an interface for the programmer. In order to facilitate the transition between different APIs, there are emerging research projects in the field of automated API migration. However, there is a lack of basic statistical background information about in-the-wild usage of APIs as such measurements have, until now, only been done on rather small corpora. We thus present an analysis method suitable for measurements with large corpora. First, we create a corpus of open source projects hosted on SourceForge, as well as a corpus of software libraries. Then, all projects in the corpus are compiled with an instrumented compiler. We use a compiler plugin for javac that gives detailed information about every method created by the compiler. This information is stored in a database and analyzed.
Conventional security infrastructures in the Internet cannot be directly adopted to ambient systems, especially if based on short-range communication channels: Personal, mobile devices are used and the participants are present during communication, so privacy protection is a crucial issue. As ambient systems cannot rely on an uninterrupted connection to a Trust Center, certiffed data has to be veriffed locally. Security techniques have to be adjusted to the special environment. This paper introduces a public key infrastructure (PKI) to provide secure communication channels with respect to privacy, confidentiality, data integrity, non-repudiability, and user or device authentication. It supports three certiffcate levels with a different balance between authenticity and anonymity. This PKI is currently under implementation as part of the iCity project.
RMTI (RIP with Metric based Topology Investigation) wurde in der AG Rechnernetze an der Universität Koblenz-Landau entwickelt. RMTI stellt eine Erweiterung zum RIP (Routing Information Protocol) dar, die das Konvergenzverhalten bei Netzwerkveränderungen, insb. bei Routingschleifen, verbessern soll. Dies geschieht durch Erkennen von Routingschleifen und Reduzieren des Count-to-infinity Problems. Um dieses gewünschte Verhalten nachweisen zu können, bedarf eine reichhaltige Evaluierung des RMTI- Algorithmus. Hierzu wurde in der gleichen Arbeitsgruppe die Client-/Server-Applikation XTPeer entwickelt. In Kombination mit anderen Software wie VNUML und Quagga Routing Suite lässt sich per XT-Peer der Algorithmus evaluieren. Die Applikation XTPeer generiert durch die Simulationen Daten. Diese können in Form von XML konforme SDF-Dateien exportiert werden. Diese können ohne weitere Auswertungen wieder in die XTPeer Applikation importiert werden. Die Evaluierung der Simulationen findet automatisiert nur an der aktuellen Simulation statt. Evaluierung über mehrere Simulationen muss der Benutzer manuell berechnen. Um diese Evaluierungsarbeiten für den Benutzer zu vereinfachen, verfolgt die vorliegende Diplomarbeit daher das Ziel, die XTPeer Applikation mit einem Auswertungsmodul zu erweitern. Die Auswertungen soll sich über alle gespeicherten Simulationsdaten und nicht wie bisher nur über die aktuell laufende Simulation erstrecken. Dies ermöglicht bessere statistisch verwertbare Aussagen. Zusätzlich können diese Auswertungsergebnisse grafisch unterstrichen werden.
In this thesis a Java program is developed that can be used to visualize networks previously described in configuration files. These networks must consist of layer 2 switches and hosts only. After loading such a configuration file, the program will visualize the network, and the spanning tree algorithm IEEE 802.1D may be started. The program allows the user to modify specific attributes of switches and hosts. The hosts will be able to exchange messages. The switches are realized as threads so that they can run independently and parallel to each other. The absence of central coordination and control prevents the switches from sharing global knowledge. This characteristic renders the implementation closer to the way an actual network functions.
The processing of data is often restricted by contractual and legal requirements for protecting privacy and IPRs. Policies provide means to control how and by whom data is processed. Conditions of policies may depend on the previous processing of the data. However, existing policy languages do not provide means to express such conditions. In this work we present a formal model and language allowing for specifying conditions based on the history of data processing. We base the model and language on XACML.
A network like the internet is a set of subnets that are connected to each other by a router. A router is a computer, containing multiple network devices to be connected to multiple subnets. So, it is able to forward packages from one subnet to another. A network can be represented as a graph with its routers as vertices and subnets as edges. This graph is called the topology of the network. A packet send to a host outside the own subnet usually will be send first to the so-called default router. This router (like any router) contains a table (the so-called forwarding table) with every subnet. Additionally for each net, the table contains the router through which the subnet can be reached best. So, the packet will be forwarded from router to router until it reaches the destination subnet. On this way every router looks up in its forwarding table for the best next router. A routing protocol takes care of the automatic exchange of informations between the routers to build the forwarding tables and keep them up to date. If the forwarding tables of all routers are up to date the network is called convergent. The time needed to build or update the routing tables is called the convergence time The RIP routing protocol is a well known and well explored distance vector protocol. But there are only few examinations about the convergence properties (e.g. the time needed to converge or the traffic volume produced by the routing messages). This work tries to examine a relationship between the topology properties of a network and the convergence properties of the rip routing protocol. Therefore, over 5000 single measurements were performed and statistically analyzed. Mathematical formulas have been derived from the results that are able to approximate the convergence properties of a network from its topology properties.