 In the presented approach, the dimensioning for the backbone link takes the possible multiplexing gain of the aggregated traffic into consideration. Thus the calculated bandwidths from the proposed analytical approaches show overbooking capability on the backbone link. The suggested dimensioning approaches can be applied for both ATM and IP based transport network, as the effect of the implemented traffic control and resource control functions for the transport of the circuit-switched traffic in both transport networks are quite similar. The main difference lies in the transport overheads due to different transport protocols and underlying transport layers. Therefore, when applying the proposed dimensioning approach, the proper transport overheads corresponding to each transport network need to be taken. It needs to be noted that other analytical approaches can be applied for dimensioning the multi-lub radio access network, depending on the QoS requirements of the network operators. For example, if the dimensioning is only focused on the transport network QoS at both last mile link and the backbone link, then each link can be dimensioned with the MMPP/D/1 queuing model individually. However, different approaches will result in different dimensioning results which in turn lead to different network costs. The selection of a most suitable approach is dependent on the QoS requirements of the network operators. 8.3 Dimensioning for Elastic Traffic in ATM-Based UTRAN As known, processor sharing models are proposed to dimension for the elastic traffic for a guaranteed user application QoS and have been demonstrated for the single lub link scenario in both ATM and IP RAN. This section presents extended analytical approaches based on processor sharing models for dimensioning an ATM based multi-lub radio access network transmitting elastic traffic. The next section will present the dimensioning approach for an IP based multi-lub UTRAN. 8 Dimensioning for Multi-lub RAN Scenario As mentioned in section 8.1.1, for setting up