esired delay factor f. With these input parameters, the optimum capacity C can be computed by applying the developed M/G/R-PS models. For different UMTS network scenarios, e.g. with a single RAB rate or multiple RABs or applying BRA, with or without admission control CAC etc, the different corresponding extensions need to be applied for estimating the average transfer delay, as presented in section 6.3.7. However, in most cases it is not possible to solve these expected sojourn time equations explicitly for C. Therefore, an iterative approach is suggested, which is according to the general dimensioning procedure introduced in Chapter 4.3. That means, the average transfer times are interactively calculated for adapting the capacities C. Starting from a value of p, C can be adjusted (incremented or decremented) in small intervals (e.g. 10 kbps) until the desired QoS is achieved, i.e. until throughput D D D or T(x) T,. The obtained optimum capacity C is then the outcome of the dimensioning result for the lub link for a desired application QoS. The following describes individual dimensioning procedures for different scenarios. Unlimited Peak Rate If there is no limitation on the peak data rate on the elastic traffic flows, M/G/1-PS model should be used as R = 1. For negligible round trip times, the optimum capacity C can be calculated explicitly from the basic M/G/1-PS model (equation (6.18)). For a desired throughput D1, C can be calculated with equation below. C = D, + p (6.41) or in case the QoS requirement is expressed by means of the delay factor f C=,Lip (6.42) If the effect of long round trip times should be taken into account, equation (6.24) with R = 1 has to be used. However, it is not possible to solve this equation explicitly for C, thus the interactive approach has to be used in this case. 6 Dimensioning for Single ATM-Based lub Single RAB without Applying CAC For a single RAB scenario, if elastic traffic is not controlled by the CAC, equation (6.26) and (6.27) are proposed in section 6.3.7.1 for calcula