For a
station in a data communication network having a predefined limit of congestion for handling data immediately undergoing transmission through the
station, a
system for improving service given to network users requesting new access services to support new transmissions through the same
station while the predefined congestion limit is exceeded. This
system contains: a first element for determining when the predefined limit is exceeded by existing data transmissions through the station; and a second element, responsive to requests for new access services that are received while the predefined limit is being exceeded for: concurrently
processing the request for new service and reducing the
quality of service (QoS) to selected users. The reductions in QoS generally have the effects of reducing the speed / priority of handling of data being transmitted to or from the selected users, and of freeing up of sufficient bandwidth to accommodate the requested new access services. The
system includes a third element for restoring / upgrading QoS, to users whose QoS has been reduced, when bandwidth usage subsides to a level allowing for such restoration. This latter level is sufficiently less than the congestion limit to provide a
hysteresis effect that delays actions by the third element sufficiently to prevent successive actions of said second and third elements from producing unstable fluctuations in the operation of the station. Arrangements are disclosed for applying the invention in a
cable television network environment and in
private network environments serving a single
business enterprise such as a banking institution.