Call traffic control

• US 5,060,258 A
• Filed: 07/10/1990
• Issued: 10/22/1991
• Est. Priority Date: 03/21/1988
• Status: Expired due to Term

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Turner, Peter M. D.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US07/543,755
• Time in Patent Office: 469 Days
• Field of Search: 379/134, 379/137, 379/113, 379/112, 379/258, 379/196
• US Class Current: 379/134
• CPC Class Codes: H04M 3/36 Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks
• CPC Class Codes: H04Q 3/66 Traffic distributors

Abstract

There are disclosed a method of call control (gapping) and a communications switching system in which such method is implemented, the system incorporating a call gapping arrangement for limiting the recurrence rate of successive call attempts for a particular type of call, for example to a national phone-in number, the arrangement comprising a clock (10) for determining a succession of call gapping intervals; a first up/down counter (18) having a limit N; a signal generator (11) responsive to the clock and coupled to the counter (18) to increment it by a value m each interval; a second up/down counter (21) having a limit M less than N, the counters (18, 21) being responsive to call processing circuitry (14) to be decremented for each call attempt effected by the system: a comparator (15) responsive to the content of counter (21) becoming zero to inhibit the call processing circuitry (14) from allowing call attempts. The performance of the call gapping method is nearly ideal, and it can be left permanently operational.

Claims

1. A method of controlling call traffic in a communications switching system wherein the recurrence rate of successive attempts for a particular type of call is limited, characterised by setting a predetermined allowance of call attempts in each of a succession of equal time intervals, and by carrying forward unused allowance cumulatively.

2. A method as claimed in claim 1 characterised by limiting the number of call attempts in an interval.

3. A method as claimed in claim 1 characterised by limiting the amount of accumulated allowance.

4. A method as claimed in claim 3 characterised by limiting the number of call attempts in an interval to a value less than the value of the limit of accumulated allowance.

5. A communications switching system comprising means for limiting the recurrence rate of successive attempts for a particular type of call, characterised by clock means for establishing a succession of equal time intervals;

a first accumulating means;

presettable signal generating means responsive to the clock means and arranged to send to the first accumulating means each time interval a preset signal representative of the average number of call attempts per interval that are to be allowed;

a second accumulating means for accumulating the number of call attempts that are effected by the system;

decision means responsive to the contents of the first and second accumulating means to allow a call attempt only while the content of the second accumulating means is less than that of the first accumulating means.

6. A system as claimed in claim 5 characterised in that said first and said second accumulating means are together constituted by a single accumulating means which is incremented by said preset signal and decremented in response to call attempts effected by the system;

and said decision means allows a call attempt only while the content of said single accumulating means is greater than zero.

7. A communications switching system comprising means for limiting the recurrence rate of successive attempts for a particular type of call, characterised by clock means for establishing a succession of equal time intervals;

a single accumulating means;

presettable signal generating means responsive to the clock means and arranged to send to the single accumulating means each time interval a preset signal representative of the average number of call attempts per interval that are to be allowed;

said single accumulating means being arranged to be incremented by said preset signal and decremented in response to call attempts effected by the system;

a storing means for storing the number of call attempts that are allowed in any one interval, said storing means having a capacity less than that of said single accumulating means;

means for presetting the storing means at the start of each interval with the current value in said single accumulating means;

a further accumulating means for accumulating the number of call attempts that are effected by the system in an interval; and

decision means responsive to said storing means and said further accumulating means to allow a call attempt only while the content of said further accumulating means is less than that of said storing means.

8. A system as claimed in claim 7 characterised in that said storing means and said further accumulating means are together constituted by another single accumulating means which is decremented in response to call attempts effected by the system;

and said decision means allows a call attempt only while the content of said another single accumulating means is greater than zero.

9. A call traffic control subsystem for use in a communications switching system comprising means for limiting the recurrence rate of successive attempts for a particular type of call, the subsystem being characterised by clock means for establishing a succession of equal time intervals;

a first accumulating means;

presettable signal generating means responsive to the clock means and arranged to send to the first accumulating means each time interval a preset signal representative of the average number of call attempts per interval that are to be allowed;

a second accumulating means for accumulating the number of call attempts that are effected by the system;

decision means responsive to the contents of the first and second accumulating means to allow a call attempt only while the content of the second accumulating means is less than that of the first accumulating means.

10. A subsystem as claimed in claim 9 characterised in that said first and said second accumulating means are together constituted by a single accumulating means which is incremented by said preset signal and decremented in response to call attempts effected by the system;

and said decision means allows a call attempt only while the content of said single accumulating means is greater than zero.

11. A call traffic control subsystem for use in a communications switching system comprising means for limiting the recurrence rate of successive attempts for a particular type of call, the subsystem being characterised by clock means for establishing a succession of equal time intervals;

a single accumulating means;

presettable signal generating means responsive to the clock means and arranged to send to the single accumulating means each time interval a preset signal representative of the average number of call attempts per interval that are to be allowed;

said single accumulating means being arranged to be incremented by said preset signal and decremented in response to call attempts effected by the system;

a storing means for storing the number of call attempts that are allowed in any one interval, said storing means having a capacity less than that of said single accumulating means;

means for presetting the storing means at the start of each interval with the current value in said single accumulating means;

a further accumulating means for accumulating the number of call attempts that are effected by the system in an interval; and

decision means responsive to said storing means and said further accumulating means to allow a call attempt only while the content of said further accumulating means is less than that of said storing means.

12. A subsystem as claimed in claim 11 characterised in that said storing means and said further accumulating means are together constituted by another single accumulating means which is decremented in response to call attempts effected by the system;

and said decision means allows a call attempt only while the content of said another single accumulating means is greater than zero.