Traffic congestion

• US 20040071086A1
• Filed: 11/14/2003
• Published: 04/15/2004
• Est. Priority Date: 12/22/2000
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Haumont, Serge, Mäkelä, Tero
• Granted Patent: US 7,688,731 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 2012/5634 In-call negotiation
• CPC Class Codes: H04L 2012/5636 Monitoring or policing, e.g. compliance with allocated rate, corrective actions
• CPC Class Codes: H04L 2012/5682 Threshold; Watermark
• CPC Class Codes: H04Q 3/0091 Congestion or overload control

Abstract

The invention relates to methods and apparatus for controlling traffic congestion of communication traffic in a communication network. The network includes a first node which is operable to receive communication traffic in the form of data from one of more sending nodes and to pass that data to one or more receiving nodes. The method includes monitoring the possible output data rate of the first node and detecting if the possible output data rate becomes smaller than a maximum data rate value and responsive to that monitoring step performing congestion control whereby the data throughput of a flow of data through the first node is decreased.

Claims

1. A method of controlling congestion of communication traffic in a communications network, the network comprising a first node operable to receive communication traffic in the form of data from one or more sending nodes and to pass said data to one or more receiving nodes, the method comprising:

monitoring the possible output data rate of said first node and detecting if the possible output data rate becomes smaller than a maximum data rate value; and

responsive to said monitoring step performing congestion control whereby the data throughput of a flow of data through said first node is decreased.

2. A method as claimed in claim 1, wherein said maximum data rate value is equal to a maximum possible rate of receipt of data at said first node minus a predetermined threshold value.

3. A method as claimed in claim 1 or claim 2, wherein said step of performing congestion control comprises decreasing the maximum throughput of a new data flow being requested.

4. A method as claimed in any one of claims 1 to 3 wherein said step of performing congestion control comprises decreasing the maximum throughput of a pre-established data flow.

5. A method as claimed in claim 1 further comprising:

via a second node, negotiating selected communication traffic parameters with said first node thereby controlling the flow of communication traffic through said first node.

6. A method as claimed in claim 5, where said communication traffic parameter comprises a maximum bit rate value, and said second node comprises a policing function to enforce the said maximum bit rate.

7. A method as claimed in any preceding claim, the method further comprising:

temporarily holding data in a data store of said first node if the rate of receipt of data at said first node exceeds a data throughput rate of the node;

monitoring the level of occupancy of the data in the data store having regard to at least one threshold data occupancy level; and

performing congestion control responsive to the monitored data occupancy level reaching the at least one threshold level.

8. A method as claimed in any preceding claim, wherein said step of performing congestion control is carried out in dependence upon previous traffic loading conditions of the network.

9. A method as in claims 7 or 8, wherein the at least one data occupancy threshold level is adjusted taking into account network conditions.

10. A method as in claims 7, 8 or 9 wherein the at least one data occupancy threshold level is adjusted taking into account preceding data occupancy levels.

11. A method as in any preceding claim, when dependent on claim 7, wherein the or each threshold data occupancy level is adjusted based on expected future traffic loading conditions.

12. A method as in any preceding claim, when dependent on claim 7, wherein information on preceding data occupancy levels comprises an average of a predetermined number n of previous data occupancy level measurements.

13. A method as in any preceiding claim wherein dependent on claim 7, wherein information on preceding data occupancy levels comprises an average of a predetermined number m of previous data occupancy level measurements, wherein m>

n, the average being weighted towards the most recent measurements.

14. A method as in any preceding claim, wherein the degree of congestion control performed at periods of high congestion risk exceeds that performed at periods of lower congestion risk.

15. A method as in any preceding claim, wherein the degree of congestion control performed is varied based on anticipated future traffic levels.

16. A method as claimed in any preceding claim, wherein time periods during which the network operates are categorised according to congestion risk.

17. A method as claimed in any preceding claim, when dependent on claim 7, wherein a different threshold occupancy level is used to trigger congestion control in time periods of different categories.

18. A method as in any preceding claim, wherein a communication node requests a data transfer rate and a congestion control measure performed includes connecting a new data flow with a lower than requested transfer rate.

19. A method as in any preceding claim, wherein a congestion control measure performed includes reducing the transfer rate of an established data flow by a predetermined amount.

20. A method as in any preceding claim, wherein a congestion control measure performed includes rejecting a request to establish a new data flow.

21. A method as in any preceding claim, wherein a congestion control measure performed includes terminating an established data flow.

22. A method as in any preceding claim, wherein a combination of congestion control measures are performed at the same time.

23. A method as in any preceding claim, wherein congestion control is performed on a new data flow in preference to or to a greater extent than on an established data flow.

24. A method as in any preceding claim, wherein the communication traffic is comprised of data having different levels of priority and congestion control measures are performed taking into account the priority level of the data.

25. A method as in claim 24, wherein the type of congestion control measure is selected in dependence on the priority level of data.

26. A method as in claim 22 to 25, wherein communication traffic is comprised of a plurality of different classes of data, each said class of data being held in a different data storage location of the data store.

27. A method as in claim 26, wherein different threshold data occupancy levels are applied to the different storage locations of the data store.

28. A method as in any preceding claim, wherein the at least one threshold level comprises a set of threshold levels.

29. A method as in claim 24, performed in a cellular communication network, where said different priority levels are based on a quality of service parameter.

30. A method as in claim 29, wherein data is prioritised based on allocation and/or retention priorities in a UMTS network.

31. A method as in any preceding claim, wherein said first node comprises a radio network subsystem.

32. A method as in any of claims 1 to 31, wherein said first node comprises one of:

a radio network controller;

a serving GPRS support node;

a gateway GPRS support note; and

another node in a PLMN network.

33. A method as in any preceding claim, wherein a throughput rate request from a communicating node is recorded.

34. A method as in any preceding claim, wherein information on data losses is passed between nodes for the purposes of charging.

35. Apparatus for controlling congestion of communication traffic in a communications network, the network comprising a first node operable to receive communication traffic in the form of data from one or more sending nodes and to pass said data to one or more receiving nodes, the apparatus comprising:

means for monitoring the possible output data rate of said first node and detecting if the possible output data rate becomes smaller than a maximum data rate value; and

means, responsive to said monitoring step, for performing congestion control whereby the data throughput of a flow of data through said first node is decreased.