ub transport network need to be defined. It is proposed to use the same ideas of dimensioning the ATM based multi-lub radio access network which are presented in section 8.3.2. In section 8.3.2, three basic approaches are proposed to allocate the separate target delay factors for the last mile link and the backbone link individually, according to the requested application QoS level and the required network costs. All of these three proposed approaches can also be applied for dimensioning a star-structured IP RAN. In this thesis approach (3) is presented for dimensioning the multi-lub IP RAN, due to its wide applicability, fine accuracy, and capable of overbooking as validated in section 8.3 for the ATM based multi-lub RAN. For a certain class of elastic traffic flows that is carried by one of the AF or BE PHBs, the target end-to-end QoS requirement for this service class is an expected time period for 8 Dimensioning for Multi-lub RAN Scenario transmitting a certain amount of bytes, or simply a value for the target end-to-end delay factor f arget It is assumed that the QoS requirement of this service class is applied throughout the network. According to the approach (3) in section 8.3.2, the assigned target delay factor for each last mile link fac and for the backbone link fbb will be calculated with equation (8.6). After allocating a proper target delay factor for the last mile link and the backbone link for each service class, the dimensioning of the IP RAN transport network (which is carrying several service classes) is performed by calculating the required minimum IP bandwidth for each link individually, which needs to guarantee the target delay factor of every service class on that link. The calculation for the required minimum IP bandwidth of each link in this case can be according to the proposed the dimensioning approach for a single link presented in section 7.3.1 and section 7.3.3. The resultant dimensioning approach is illustrated in Figure 8.13. In Figure 8.13, it is assumed that there are n Node Bs in