Congestion control system for telecommunications
AssigneeNorthern Telecom Limited
InventorsFrancis Langlois, France Caron, Jean M. Regnier
Life of this patent
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Abstract
A congestion control system is provided which is an enhancement of the dynamic call routing system taught by Szybicki et al. in U.S. Pat. No. 4,284,852. The congestion control system includes two parts, a restrictive control and an expansive control. The restrictive control uses data collected by the network processor to provide a call gapping recommendation which is automatically updated each cycle (typically 10 seconds). The call gapping recommendation is used to restrict entry of calls to the network. The expansive control system uses a call compression factor to deflect tandem traffic from overloaded nodes. If direct traffic continues to increase, the restrictive control takes over from the expansive control.
Claims12
In a telecommunications network having a plurality of switching offices interconnected by trunks and connected to a central processor for periodically exchanging data, with the central processor during an update cycle, to effect dynamic call routing, a method of congestion control comprising the steps of:
- at the beginning of an update cycle, receiving data, from the switching offices, indicative of occupancy of network resources for updating data of the central processor;
- determining from the data whether there are destinations within the network to which access is to be restricted;
- establishing an alert status for each of the restricted destinations;
- calculating, for each of the restricted destinations, an interval of time to be left between calls entering the network that are directed thereto and referred to as a call interarrival time;
- and
- the central processor, during the update cycle, sending, to the switching offices, an identification for each of the restricted destinations, together with the alert status and the call interarrival time therefor for updating data of the switching offices for dynamic call routing and congestion control.
In a telecommunications network having a plurality of switching offices interconnected by trunks and connected to a central processor for periodically exchanging data, with the central processor during an update cycle, to effect dynamic call routing, a method of congestion control comprising the steps of:
- at the beginning of an update cycle, receiving data, from the switching offices, indicative of occupancy of network resources for updating data of the central processor;
- for each origin-destination pair of the plurality of switching offices, recommending a tandem switching office in dependence upon occupancy of trunks to the switching office and CPU occupancy of the switching office;
- determining from the data whether there are destinations within the network to which access is to be restricted;
- establishing an alert status for each of the restricted destinations;
- calculating, for each of the restricted destinations an interval of time to be left between calls entering the network that are directed thereto and referred to as a call interarrival time;
- and
- the central processor, during the update cycle, sending, to the switching offices, an identification for each of the restricted destinations, together with the alert status and the call interarrival time therefor for updating data of the switching offices for dynamic call routing and congestion control.
Dependencies are inferred from the claim text.