Seminar paper from the year 2005 in the subject Computer Science - Commercial Information Technology, grade: A (1,3), University of Auckland (Facultiy of Computing), course: Network and Protocols, language: English, abstract: Voice over IP (VoIP) is at the moment one of the most discussed topics in the current network scene. Besides the theoretical interest in network development, there is always the practical relevance which is of high importance for advances in network technology. One major proof, that VoIP research and its technology has a high impact on businesses is the fact that VoIP it is already implemented in a number of companies in the United States of America, UK, Ireland and South Korea, according to Cherry (2005). The following graphic shows the importance of VoIP for companies according to a recent international study conducted by Network Computing.