This paper describes a simulation based study of the end-to-end performance of admission control and policing mechanisms in an ATM network supporting different types of traffic. Several conclusions can be derived from this study. First, the source model used has no significant impact on the ratio of cell losses. Second, preventive congestion control schemes have only limited effects in dealing with network congestion, unless the network is equipped with large buffer sizes. Third, cascaded policing mechanisms, such as policing mean cell rate and policing peak cell rate, may be required to achieve high level control. Forth, trade-offs between acceptable buffer sizes and end-to-end performance may be required to operate an ATM network within the range of medium to high mean offered load. Fifth, several levels of congestion control may be required, unless trade-offs between buffer sizes and end-to-end performance requirements are adequately achieved. The results illustrated in this paper may serve as a starting point for further investigating the coupling between network access modes and endpoint control mechanisms.