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Universität Fribourg

Ich studierte von 1998 bis 2003 für den Master und anschliessend 2004 bis 2007 für den Doktortitel an der Universität Fribourg.
In dieser Rubrik stelle ich einige Arbeiten, die ich während meinem Studium an der Uni Fribourg geschrieben und programmiert habe, zur Verfügung. Chronologisch kommt zuerst eine Reihe von Konferenzbeiträgen aus dem Doktorat, dann die Arbeiten als Student.
Ich bitte um eine Benachrichtigung, falls Sie aus meinen Arbeiten zitieren oder Code verwenden.

Die meisten Dokumente wurden mit Latex erstellt, mehr Informationen zu diesem Textsystem hier.

Improving Network Reliability by avoiding Misconfiguration

DRCN 2007, La Rochelle, France, 7-10 October, 2007.

Abstract: One source of network operation interruption is the human factor. In this paper, we discuss how network management systems can help to avoid mistakes in configuration. While ensuring correct syntax of configuration data is nothing novel, testing its semantics has become a challenge to network management.
We illustrate possible solutions with the Verified Network Configuration (Verinec) project. A central XML database is used to model the network and device configuration. All configuration is tested before the setup of the real devices is modified.

PhD Thesis accepted

I can now officially call myself a doctor! My PhD thesis has been accepted by the University of Fribourg. You can read the abstract of my thesis on this page. If you want to read the whole thesis, find it at ethesis.unifr.ch or if it disapeared from there, just drop me an Email.

Assessment of code quality through classification of unit tests in VeriNeC

(Together with Dominik Jungo)
AINA 2007, Niagara, Canada, May 21-23, 2007.
Abstract: Unit testing is a tool for assessing code quality. Unit tests check the correctness of code fragments like methods, loops and conditional statements. Usually, every code fragment is involved in different tests. We propose a classification of tests, depending on the tested features, which delivers a higher detailed feedback than unclassified tests. Unclassified tests only deliver a feedback whether they failed or succeeded. The detailed feedback from the classified tests help to do a better code quality assessment and can be incorporated in tools helping to improve code quality. We demonstrate the power of this approach doing unit tests on network configuration.

A role model to cope with the complexity of network configuration

INOC 2007, Spa, Belgium, April 22-25, 2007.
Abstract: In this paper, we propose a role model to cope with the complexity of network configuration. Roles associate policy requirements as well as configuration templates with nodes in the network. One goal is to remove redundancy in configuration data to avoid inconsistent changes and diverging setup of similar devices. The other goal is to ensure that network policies are respected by the configuration.
This role model is embedded into the project Verified Network Configuration (Verinec). Together with
the Verinec XML network model, roles provide a powerful instrument to configure large networks.

Assessment of code quality through classification of unit tests in VeriNeC

(Together with Dominik Jungo)
WINSYS 2006, Portugal August 7-10, 2006.
Abstract: The type or class of an object is not always sufficient to decide on its runtime behaviour. In many cases, the
context of the object is also important. Environmental acquisition is a concept to handle context in information
We explore the use of environmental acquisition for the management of computer network configuration and
for network simulation. Physical location or subnet membership are part of the environment for a computer
in a network. For the simulation of networks, environmental acquisition will be especially useful to model
mobile devices moving from one area into an other.
The concept is illustrated using the network configuration management project Verinec.

CLiXML - Testing of semantic properties in XML documents

MSVVEIS 2006, Cyprus May 23-24, 2006
Abstract: XML is a markup language with a clear hierarchical structure. Validating an XML document against a schema document is an important part in the work flow incorporating XML documents. Most approaches use grammar based schema languages. Grammar based schemas are well suited for the syntax definition of an XML document, but come to their limits when semantic properties are to be defined. This paper presents a rule based, first order schema language, complementary to grammar based schema languages, demonstrating its strength in defining semantic properties for an XML document.

Automated Configuration Distribution in Verinec

ICETE 2005, Reading, UK October 3-7, 2005.
Abstract: We present in this paper a system to configure networks. The Verified Network Configuration (Verinec) project aims to manage the complete network from one central XML database. This approach allows to test whether the configuration is usable prior to modify the setup of the real network devices.

The distribution of the configuration is handled by the adaption module, a framework which can be extended to support all kinds of services and devices. Applying the configuration to each managed device within the network requires conversion from the Verinec XML database into a format suitable for that device and send the configuration to the device using a protocol supported by that device. In this paper, we focus on the adaption module.

A Unit Testing Framework for Network Configurations

MSVVEIS 2005, Miami, USA May 24, 2005.

Abstract: We present in this paper a unit testing framework for network configurations which verifies that the configuration meets prior defined requirements of the networks behavior. This framework increases the trust in the correctness, security and reliability of a networks configuration. Our testing framework is based on a behavioral simulation approach as it is used in hardware design.

The Role of Simulation in a Network Configuration Engineering Approach

ICICT 2004, Cairo, Egypt December 6-7, 2004.
Abstract: We report in this paper on a network simulator, which allows checking behavioural properties of a network prior to the real configuration of the network. Properties such as filtering strategies of firewalls, the correct functionality of DNS or DHCP servers, etc. can be tested using the simulator. In the presented approach, the entire network configuration and topology is represented as eXtensible Markup Language (XML) documents, which the simulator reads and operates on accordingly. After successful tests of the network using the simulator, the XML configuration description will be translated automatically into configuration files that are used to configure the concrete services present in the actual network. The translation will be performed using eXtensible Stylesheet Language Transformations (XSLT).

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