route in the interval as measured by number of release rel messages with an acl parameter rather than by the number of address complete messages received the calling rate o new offered to the source for the target node is also measured in each interval with a smoothed value held in o smooth d smooth is used to determine the leak rate of a notional leaky bucket used to restrict calls to the target node should it be in overload o smooth is used to determine when to lift the restriction initial values for d smooth and o smooth are set in the source node in configurable data determined by network and node dimensioning if a call is rejected with an isup rel message containing an acl parameter and acc is not active for the route then acc is activated for the route timer t short is started for the route the overload status level of the route is set to the value of the acl parameter 1 or 2 for itu t isup calls to the target are restricted by the source using a leaky bucket whose rate is calculated using an exponential smoothing formula with inputs the current leaky bucket rate l level and d smooth a separate leaky bucket rate and leaky bucket size are used for level 1 and level 2 their.