y improves the utilization of the transport resource and save the operation expenses while guaranteeing the desired QoS. 3.3.4.3 Transport Resource Management (TRM) In contrast to the RRM, Transport Resource Management (TRM) is to control and manage the transport resources in the terrestrial radio access network in order to achieve an efficient use of the transport resources while provide guaranteed QoS. Following gives a detailed introduction of transport network admission control function, Transport Network Layer Connection Admission Control (TNL CAC), which is considered for the dimensioning in this thesis. Unlike the admission control in the RRM group which controls the wireless resources in the WCDMA air interface where the resources are the transmission power and the interference, the Transport Network Layer (TNL) CAC is based on the transport resources supplied by the underlying wired transport network. TNL CAC is used to decide whether there are sufficient free resources on the requested link to allow a new transport connection. A 3 UMTS Terrestrial Radio Access Network (UTRAN) connection can only be accepted if adequate resources are available to establish the connection with promised QoS while the agreed quality of service of the existing connections in the network must not be affected by the new connection. It shall be noted that in this thesis, the management and dimensioning of the transport resource is the major concern, SO only TNL CAC is considered in this thesis (the CAC used in the radio interface is not considered in the thesis). In the rest of this thesis, the term CAC means the TNL CAC. As the transport network within the terrestrial radio access network of UMTS Rel99 is based on ATM, the transport resource is the underlying ATM transport network with installed ATM links, leased ATM circuits or paths and their offered QoS, and intermediate ATM switches/routers. If an ATM VP or VC is used for the lub interface in the UTRAN transport network, the total resources provided by this VP or VC is det