For seamless and wideband mobile services, the emerging 3rd generation mobile multimedia network (IMT-2000) become focus of research and development. ITU has been standardizing the IMT-2000 functional model and possible physical mapping scenarios as standardization stage 2. Based on the ITU functional model, this paper studied what the most effective mapping scenario is, by comparing 2 mapping cases in question, the functional-level analysis and simulations, concerning the mobility management and mobile multimedia service delays. Solution for issue 2 is SACF in MSC, because SACF does non-call/non-bearer associated service and it has more interactions with core network than radio network. Also because SACF abstracts radio link aspects within core network, it should be allocated as close as possible to radio network, so SACF should be in MSC[3]. Solution for issue 3 is not clear, because the functionality of TACF does not wholly depend on one side. The TACF functionality is : (a) interact with TACAF(Terminal Access Control Agent Function) for establishment and release of the association between IMT-2000 terminal/user and the network (b) establish, maintain, modify and release the radio and bearer connections between a mobile terminal and the network (c) interact with RRC(Radio Resource Control plane) regarding the assignment of radio resources (d) terminal paging execution, paging response detection and handling (e) handover decision, execution, completion (f) trigger access to terminal access activities to IN functionality From the functions stated in items (a), (b), (c) and (e), TACF has more interactions with mobile side, so it is thought to be more like in BSC close to mobile side. But if we consider the item (d) and (f), TACF has more interactions with network side, so MSC is thought to be a more appropriate position for TACF. In this paper, we developed analytic and simulation models to find the best position for TACF. This is a functional level analysis, which means that each functional entity is one-to-one mapped to a physical software block. And the analysis is in end-to-end delay point of view.