This paper compares two technologies for ATM access networks, BBL (BroadbandLoop) and FSAN (Full Service Access Networks), and discusses methodologies for dimensioning these networks. Several resource management strategies, based on the virtual path concept, are considered. Statistical multiplexing both at the service and call level is studied. It is seen that the network topology and the service characteristics allow several simplifications in the call and cell level dimensioning processes. The dimensioning procedures are illustrated through some case studies.