Acknowledgement

First of all I would like to thank Professor Dr. Torsten Braun for all of his support and for letting me write this diploma thesis in his research group Computer Networks and Distributed Systems. Also many thanks go to Dr. Marc-Alain Steinemann who supervised my work, gave me assistance whenever needed and had patience with me when my work was not progressing as fast as planned. Last but not least I would like to thank everyone else from the research group for all the inspiring discussions and interesting ideas we shared. i i