1.4). For these two traffic classes, section 6.2 and section 6.3 present two individual analytical dimensioning models at flow or connection level for their respective user-relevant QoS. Section 6.4 proposes analytical models for dimensioning the lub link at network level to guarantee the relevant transport network QoS. The validity of the proposed analytical models is demonstrated by means of extensive simulations. Section 6.5 summarizes the main investigations of dimensioning for the ATM-based HSPA networks. 6.1 Overview and Objectives In this chapter, the dimensioning process considers a single link, as shown in Figure 1.2 (a). It can be applied to the situations that the Node B with a direct link to the RNC or a logical lub interface with an identifiable bottleneck. In the latter situation, other links might exist on the lub interface but their influence on the user and network performance is considerably less than the bottleneck and therefore they can be neglected. Overall, the objective is to minimize the bandwidth costs while still meeting a desired degree of QoS. Given a certain traffic demand per traffic class, the amount of aggregated traffic carried on the lub link need to be estimated. From this, the minimum required link bandwidth should be derived for a specific QoS target. Every dimensioning procedure requires a model, which provides a relationship between the amount of offered load, the link bandwidth, and the achieved QoS, taking into account the characteristics of the workload and the transmission process. For the circuit-switched traffic, it is assumed that it is generated by real time services with strict QoS requirements, which need to be guaranteed by the network with a guaranteed bandwidth. The resultant analytical dimensioning model needs to consider traffic characterization at connection level and the influence of admission control function. In case of elastic traffic the packet transmission process is mainly affected by the rate-sharing features of TCP. The proposed network dimensioning 