A device is configured to detect congestion and throttle phone calls in a telephone communication system. The device is configure to receive, from a telephone dialing system, an indication indicating a call failure to a phone number; determine that the phone number matches a flooding group number based on initial digits of the phone number, the flooding group number associated with a flooding group, the flooding group including a plurality of phone numbers with initial digits having identical values to the flooding group number; determine a time of the call failure and a number of concurrent active calls for the flooding group at the time of the call failure; and in response to the number of concurrent active calls at the time of the call failure exceeding a predefined threshold, update a capacity limit for the flooding group based on the number of concurrent active calls.

A device is configured to detect congestion and throttle phone calls in a telephone communication system. The device receives, from a telephone dialing system, an indication indicating that a call to a phone number has successfully ended. In response to the indication, the device determines that a set of initial digits of the phone number matches a flooding group number of a flooding group, where the flooding group has a capacity limit. The device determines that a maximum number of concurrent active calls for the flooding group during a predefined period of time is within a predetermined threshold from the capacity limit of the flooding group and that no failed calls have occurred for the flooding group during the predefined period of time. In response to the determining, the device increases the capacity limit of the flooding group.

A device is configured to detect congestion and throttle phone calls in a telephone communication system. The device receives, from a telephone dialing system, an indication indicating that a call to a phone number has successfully ended. In response to the indication, the device determines that a set of initial digits of the phone number matches a flooding group number of a flooding group, where the flooding group has a capacity limit. The device determines that a maximum number of concurrent active calls for the flooding group during a predefined period of time is within a predetermined threshold from the capacity limit of the flooding group and that no failed calls have occurred for the flooding group during the predefined period of time. In response to the determining, the device increases the capacity limit of the flooding group.