Abstract: A connection admission controller determines whether to admit the requested connection according to whether admission would cause a bandwidth used to exceed a maximum bandwidth allowed. For determining the bandwidth used, an aggregate equivalent bandwidth of all connections is determined by determining a static approximation and a flow approximation, the flow approximation having a non-linear relationship to the number of connections. Using a non linear relationship enables the equivalent available capacity for a number of connections to be determined more accurately with less computational resources.

Abstract: Admission control for a communications link involves maintaining a record at each end of the link of which channels on the link are free and allocating a free channel so that the probability of both ends allocating the same channel to different information flows is controllable. The record of channel identifiers is searched sequentially in different directions by the respective ends of the link to minimise the probability of simultaneous allocation before the records at each end are synchronised. New requests for admission to the link are allowed a different bandwidth threshold than requests for changes to existing connections already admitted to the link.