In asynchronous transfer mode (ATM), a traffic parameter defined as the maximum average rate at which the network agrees to accept cells and support their transfer from end to end for each user network interface (UNI). In other words, SCR is the average throughput. Enforcement of the SCR enables the network to allocate sufficient resources to ensure that the quality of service (QoS) parameters such as cell loss ratio (CLR) and cell transfer delay (CTD) are met over a period of time. SCR applies to variable bit rate (VBR) services. ATM, cell, CLR, CTD, QoS, throughput, traffic parameter, UNI, and VBR.