e made and number of extensions are proposed in this thesis to consider the specific features of UMTS and the related resource and traffic management functions in the UTRAN. In the following, section 6.3.1 gives an overview of TCP. As for elastic traffic the TCP protocol greatly influences the data transfer process and thus the dimensioning strategy, a 6.3 Dimensioning for Elastic Traffic good understanding of its fundamental properties is essential. Then the related work and the basic principle of processor sharing are given in section 6.3.2 and 6.3.3. Based on that, the rationale behind of the application of the processor sharing model for the dimensioning of the lub interface in UMTS is explained. Section 6.3.4 presents the modeling of the UMTS lub interface as an M/G/R-PS queuing system at flow level. Section 6.3.5 and 6.3.6 introduce the fundamentals of the M/G/R-PS model, which this thesis is based on. Section 6.3.7 presents in detail the main extensions proposed within this thesis for dimensioning the lub link and section 6.3.9 presents the dimensioning procedure. Afterwards, the main results of employing the proposed M/G/R-PS models for dimensioning the lub link are presented and they are validated by simulations. 6.3.1 Transmission Control Protocol (TCP) The Transmission Control Protocol (TCP) is the main transport protocol for data transmissions in the Internet. It is a connection-oriented transport protocol, which assures reliable and in-sequence data transfer. It was originally specified in [Pos81]. With the development of wired and wireless networks, many options and features have been proposed for TCP in order to enhance the performance and adapt well to ever-changing environments. Hence a variety of versions and implementations of TCP have been developed over the years with main focus on congestion control [Jac88, FH99, Flo01]. Detailed introductions of the TCP protocol can be found in [Ste94]. However, in this thesis the proposed dimensioning models for the elastic traffic only consider the fundam