The research on traffic control has not yet lead to a consensus on how to properly allocate resources in ATM networks. There are consequently no practicable methods available now when the initial deployment of ATM switches and terminals is under way. Yet, many of the applications which motivate the deployment uses multi-media and will thus require some degree of performance guarantees on the information transfer. Here we suggest a readily applicable method for reserving capacity in ATM networks. Cells using the reserved capacity may only depart at fixed time-instances, and have reserved buffers in the network nodes. The scheme gives a lossless performance, can be implemented with low complexity; it simplifies the call-acceptance and allows ``best effort'' traffic to use slack in the reserved and all of the non-reserved capacity.