Last mile load Figure 8.25: Overbooking factor over last mile loads (with different QoS requirements) 8 Dimensioning for Multi-lub RAN Scenario Last mile utilization of 50% last mile link rate = 1Mbps last mile link rate = 2Mbps Number of NodeBs Figure 8.26: Overbooking factor over number of Node Bs (various last mile capacities) pure web traffic web traffic + 10%Voice web traffic + 30%Voice web traffic + 50%Voice Number of NodeBs Figure 8.27: Overbooking factor over number of Node Bs (with different voice portions) Figure 8.27 shows that given the same amount of mean offered traffic, with a higher percentage of voice traffic, the achieved optimum overbooking is higher by taking advantage of a lower bandwidth demand of the voice traffic. The more the amount of voice traffic, the more bandwidth saving that can be achieved. 8.5.3 Comparing ATM and IP-Based Multi-lub RAN In this section, an example is given to compare the dimensioning of the ATM and IP- based multi-lub RAN. Since for both ATM and IP based UTRAN, the analytical dimensioning approaches have been already validated by simulations. The following shown dimensioning results will be derived from the individual analytical dimensioning approach presented for the ATM and the IP transport separately. In this example, in both ATM and IP based UTRAN the following parameters are configured: 8.5 Overbooking of the lub Backbone Link there are 4 Node Bs (last mile links) in the RAN, each generating the same amount of the application traffic all user flows are assigned to the same RAB rate peak = 128 kbps (only one service class is considered in this example) web traffic model: page size is 50 kbyte of a constant distribution there is no restrictions on the number of elastic traffic flows target end-to-end delay factor f = 1.3, the target delay factor for each link is assigned according to the suggested approach (3) as presented in section 8.3.2. Figure 8.28 shows the derived dimensioning for the last mile link (left diagram) and the backbone link (right diagram) over