d delay factor f. This method assumes that the average end-to-end delay T is only determined by the main congested link, therefore in this method the lub transport network can be modeled as a single congested link. Thus Tt can be calculated by applying the suggested extended M/G/R- PS models (proposed for single ATM lub link in Chapter 6.3.7) on the main congested link. Method 2: let the end-to-end delay consider the total additional delays caused by the congestion of both links. The end-to-end delay T1_i for the ith lub interface is calculated with equation (8.4). (8.4) Here Tac_i denotes the calculated delay assuming that only the last mile link is congested but the backbone link has sufficient bandwidth, which is the same as case (1). Tbb represents the calculated delay assuming that only the backbone link is congested while the last mile link is not, same as case (2). The calculations for Tac_; and Tbb use the same analytical approach suggested for the case (1) and (2). Tmin is the delay when both links are ideal (without congestions in the transport network). It will be equal to the delay of transmitting the file Xt with the peak data rate peak Thus, the additional delay caused by the last mile link is calculated as (Tac_i - Tmin) and the additional delay caused by the backbone link is -Tmin). With equation (8.4), the individual impact of each link on the end-to-end delay is taken into account. 8.3 Dimensioning for Elastic Traffic in ATM-Based UTRAN In the following, for each of the three basic network cases, the proposed analytical methods are validated with simulations. In the presented examples, the simulation scenarios are configured as follows: all users are assigned to the same RAB rate peak = 28 kbps web traffic: page size = constant (50kbyte) there is no restrictions on the number of elastic traffic flows Figure 8.5 presents the delay estimation for the case (1) where the last mile link is congested and the backbone link is ideal (i.e. with sufficient bandwidth). In the example, the backbone link is 