Congestion control system for VoIP network

• US 20030107991A1
• Filed: 04/05/2002
• Published: 06/12/2003
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tezuka, Yasuo, Sakata, Masataka, Ishikawa, Ryuji
• Granted Patent: US 7,391,765 B2
• Time in Patent Office: Days
• US Class Current: 370/229
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6456 Channel and bandwidth allocation
• CPC Class Codes: H04L 2012/6464 Priority
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit
• CPC Class Codes: H04L 47/266 Stopping or restarting the source, e.g. X-on or X-off
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 7/1275 Methods and means to improve the telephone service quality, e.g. reservation, prioritisation or admission control

Abstract

A system according to this invention executes congestion control for monitoring a packet flow which passes through a relay router in a VoIP network and in which a packet is transferred with a predetermined priority, and for, when congestion is generated by generation of a new packet flow, maintaining a transfer state of a packet of a packet flow established before the new packet flow is generated and transferred with the predetermined priority.

Claims

1. A congestion control system for a VoIP network comprising:

monitor means for monitoring a packet flow which passes through a relay router in a VoIP network and in which is set a predetermined priority; and

congestion control means for, when congestion is caused by the generation of a new packet flow, for executing congestion control for maintaining a state of a packet flow that is set the predetermined priority and that has been establishing before the congestion is caused.

2. The congestion control system for a VoIP network according to claim 1, wherein the priority of the new packet flow is changed into a priority that is lower than the predetermined priority by the congestion control.

3. The congestion control system for a VoIP network according to claim 1, wherein the new packet flow is disconnected by the congestion control.

4. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a control device of a VoIP gateway, and

the control device controls a VoIP gateway related to the new packet flow and makes the VoIP gateway change the priority of the new packet flow into a priority lower than the predetermined priority when the control device receives the congestion notice.

5. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a control device of a VoIP gateway, and

the control device controls a VoIP gateway related to the new packet flow and makes the VoIP gateway disconnect the new packet flow when the control device receives the congestion notice and disconnects the packet flow.

6. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a VoIP gateway related to the new packet flow, and

the VoIP gateway gives the congestion notice to the control device of the VoIP gateway when the VoIP gateway receives the congestion notice, and the control device controls the VoIP gateway to change the priority of the new packet flow into a priority lower than the predetermined priority.

7. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a VoIP gateway related to the new packet flow, and

the VoIP gateway gives the congestion notice to the control device of the VoIP gateway when the VoIP gateway receives the congestion notice, and the control device controls the VoIP gateway when the control device receives the congestion notice to disconnect the new packet flow.

8. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a VoIP gateway related to the new packet flow, and

the VoIP gateway changes the priority of the new packet flow into a priority lower than the predetermined priority when the VoIP gateway receives the congestion notice.

9. The congestion control system for a VoIP network according to claim 1, wherein the congestion control means gives a congestion notice to a VoIP gateway related to the new audio packet flow, and

the VoIP gateway disconnects the new packet flow when the VoIP gateway receives the congestion notice.

10. The congestion control system for a VoIP network according to claim 1, wherein the monitor means holds a sum total of a used band of at least one packet flow passing through the relay router set the predetermined priority and determines that congestion is caused when the sum total exceeds a predetermined allowable value due to generation of a new packet flow.

11. The congestion control system for a VoIP network according to claim 10, further comprising:

flow specifying information storage means for storing flow specifying information for specifying a packet flow which passes through the relay router and set the predetermined priority;

sum total storage means for storing a sum total of a used band of at least one packet flow having the flow specifying information of which is stored in the flow specifying information storage means; and

allowable value storage means for storing an allowable value of a used band by a packet flow set the predetermined priority, and

wherein, when the relay router receives a packet, the monitor means specifies a priority of the packet, when the specified priority is the predetermined priority, the monitor means refers to the flow specifying information storage means, and when the flow specifying information of the packet is not stored in the flow specifying information storage means, the monitor means calculates a used band of the packet flow of the packet, adds the calculated band value to the sum total stored in the sum total storage means, and determines whether the addition result exceeds the allowable value stored in the allowable value storage means or not.

12. The congestion control system for a VoIP network according to claim 11, wherein, when the monitor means determines that the addition result does not exceed the allowable value stored in the allowable vale storage means, the monitor means registers the flow specifying information of the packet in the flow specifying information storage means, and stores the addition result in the sum total storage means as a new sum total.

13. The congestion control system for a VoIP network according to claim 10, wherein all packet flows in which packets are transferred with the predetermined priority are audio packet flows, and

when the relay router receives an audio packet of a new generated audio packet flow, the monitor means calculates a used band of the audio packet flow of the audio packet on the basis of an RTP payload type and an IP packet length included in the audio packet.

14. The congestion control system for a VoIP network according to claim 11, wherein, when changing the priority or disconnecting is executed with regard to a packet flow having the flow specifying information of which is stored in the flow specifying information storage means, the monitor means deletes the flow specifying information of the packet flow from the flow specifying information storage means and subtracts the value of the used band of the packet flow from the sum total stored in the sum total storage means.

15. The congestion control system for a VoIP network according to claim 11, wherein the monitor means checks whether the relay router receives a packet from a packet flow having the flow specifying information of which is stored in the flow specifying information storage means within a predetermined period of time or not, deletes flow specifying information of a packet flow in which a packet is not received within the predetermined period of time from the flow specifying information storage means, and subtracts the value of the used band of the packet flow from the sum total stored in the sum total storage means.

16. The congestion control system for a VoIP network according to claim 1, wherein, when the congestion is caused, a congestion notice is given to a VoIP gateway related to the new packet flow, and

the VoIP gateway inquires a subscriber who execute telephonic communication by using the new packet flow and changes the priority of the new packet flow into a priority lower than the predetermined priority or disconnects the new packet flow on the basis of a reply from the subscriber.

17. The congestion control system for a VoIP network according to claim 16, wherein the congestion notice is given to a calling VoIP gateway of telephonic communication using the new packet flow,

the calling VoIP gateway transmits the control contents of the VoIP gateway to a called VoIP gateway of the telephonic communication directly or through a control device of the VoIP gateway when the priority of the new packet flow is changed or the new packet flow is disconnected on the basis of a reply from the subscriber, and

the called VoIP gateway changes a priority of a new packet flow having a direction opposite to the direction of the new packet flow corresponding to the telephonic communication in a priority lower than the predetermined priority or disconnects the new packet flow of the opposite direction on the basis of the control contents of the calling VoIP gateway.

18. The congestion control system for a VoIP network according to claim 4, wherein, the control device, when receives the congestion notice a predetermined number of times, controls a VoIP gateway related to the new packet flow to change the priority of the new packet flow into a priority lower than the predetermined priority.

19. The congestion control system for a VoIP network according to claim 5, wherein, the control device, when receives the congestion notice a predetermined number of times, controls a VoIP gateway related to the new packet flow to disconnect the new packet flow.

20. The congestion control system for a VoIP network according to claim 6, wherein, the VoIP gateway, when receives the congestion notice a predetermined number of times, gives the congestion notice to a control device of the VoIP gateway, and

the control device controls the VoIP gateway to change the priority of the new packet flow into a priority lower than the predetermined priority.

21. The congestion control system for a VoIP network according to claim 7, wherein, the VoIP gateway, when receives the congestion notice a predetermined number of times, gives the congestion notice to a control device of the VoIP gateway, and

the control device controls the VoIP gateway to disconnect the new packet flow when the control device receives the congestion notice.

22. The congestion control system for a VoIP network according to claim 8, wherein, the VoIP gateway, when receives the congestion notice a predetermined number of times, changes the priority of the new packet flow into a priority lower than the predetermined priority.

23. The congestion control system for a VoIP network according to claim 9, wherein, the VoIP gateway, when receives the congestion notice a predetermined number of times, the VoIP gateway disconnects the new packet flow.

24. The congestion control system for a VoIP network according to claim 4, wherein, the control device, when receives congestion notices with respect to two new audio packet flow relating to a new telephonic communication, controls a VoIP gateway relating to the new packet flows to change the priority of at least one of the packet flows into a priority lower then the predetermined priority.

25. The congestion control system for a VoIP network according to claim 5, wherein, the control device receives congestion notices with respect to two new audio packet flow relating to a new telephonic communication, controls a VoIP gateway relating to the new packet flows to disconnect at least one of the new packet flows.

26. The congestion control system for a VoIP network according to claim 6, wherein, a VoIP gateway relating to a new telephonic communication respectively receives congestion notices with respect to two new packet flows relating to the new telephonic communication and gives the congestion notices to a control device of the VoIP gateway, and

the control device controls the VoIP gateway to change the priority of at least one of the new packet flows into a priority lower than the predetermined priority.

27. The congestion control system for a VoIP network according to claim 7, wherein, a VoIP gateway relating to a new telephonic communication respectively receives congestion notices with respect to two new packet flows relating to the new telephonic communication and gives the congestion notices to a control device of the VoIP gateway, and

the control device controls the VoIP gateway to disconnect at least one of the new packet flows when the control device receives the congestion notices.

28. The congestion control system for a VoIP network according to claim 8, wherein, a VoIP gateway relating to a new telephonic communication, when respectively receives congestion notices with respect to two new packet flows relating to the new telephonic communication and gives the congestion notices to a control device of the VoIP gateway, changes the priority of one of the new packet flows into a priority lower than the predetermined priority.

29. The congestion control system for a VoIP network according to claim 9, wherein, the VoIP gateway relating to a new telephonic communication, when respectively receives congestion notices with respect to two new packet flows relating to the new telephonic communication and gives the congestion notices to a control device of the VoIP gateway, disconnects one of the new packet flows.

30. A setting system for an audio packet flow of a VoIP network comprising:

a calling VoIP gateway for setting an audio packet flow of a first direction extending from the calling side to the called side between the calling VoIP gateway and a called VoIP gateway to establish a telephonic communication call through the VoIP network;

a called VoIP gateway for setting an audio packet flow in a second direction extending from the called side to the calling side between the called VoIP gateway and the calling VoIP gateway to establish the telephonic communication call; and

a relay router for relaying audio packets transferred on the audio packet flows in the first and second directions, and

wherein, before audio packet flows in the first and second directions are set, the calling VoIP gateway transmits a test packet which has a predetermined priority set for the audio packet flows and is transferred on the audio packet flows to the called VoIP gateway,

the relay router monitors a packet flow which passes through the relay router and which is transferred with the predetermined priority, receives the test packet in the first and second directions until the test packet is turned back to the calling VoIP gateway by way of the called VoIP gateway, uses the received test packet to determine whether congestion is caused by setting the audio packet flows in the first and second direction or not, and changes the predetermined priority set for the test packet into a priority lower than the predetermined priority when the congestion is caused,

when the priority set for the test packet turned back to the calling VoIP gateway is changed, the calling VoIP gateway changes the priority of the audio packet flow in the first direction into a priority lower than the predetermined priority or disconnects the audio packet flow in the first direction, and

the called VoIP gateway changes the priority of the audio packet flow in the second direction into a priority that is set for the audio packet flow in the first direction when the priority of the audio packet flow in the first direction is changed into a priority lower than the predetermined priority, or disconnects the audio packet flow in the second direction when the audio packet flow in the first direction is disconnected.

31. A VoIP gateway functions as a calling VoIP gateway, comprising:

setting means for setting a new audio packet flow extending from a calling side to a called side and having a predetermined priority between the calling VoIP gateway and a called VoIP gateway to establish a telephonic communication call through a VoIP network;

inquiring means for inquiring of a subscriber of the telephonic communication call about control contents of the new audio packet flow when congestion is caused by setting the new audio packet flow is detected by a relay router for relaying an audio packet transferred on the new audio packet flow; and

control means for changing the priority set for the new audio packet flow into a priority lower than the predetermined priority or disconnecting the new audio packet flow according to a reply from the subscriber.

32. The VoIP gateway according to claim 31, wherein, when the priority set for the new audio packet flow is changed or the new audio packet flow is disconnected on the basis of the reply from the subscriber, the control contents are transmitted to the called VoIP gateway directly or through a control device of the VoIP gateway.

33. A VoIP gateway functions as a calling VoIP gateway, comprising:

transmission means for, when an audio packet flow in a first direction extending from a call side to a called side and an audio packet flow in a second direction extending from the called side to the calling side are set between the calling VoIP gateway and a called VoIP gateway to establish a telephonic communication call through a VoIP network, transmitting a test packet having a predetermined priority set for the audio packet flows in the first and second directions and transferred on these audio packet flows;

reception means for receiving the test packet turned back to the calling VoIP gateway by way of the called VoIP gateway; and

control means for, when the predetermined priority set for the received test packet is changed into another priority, changing a priority of the audio packet flow in the first direction into a priority lower than the predetermined priority, or disconnecting the audio packet flow in the first direction.

34. The VoIP gateway according to claim 33, wherein, when the priority set for the new audio packet flow is changed or the new audio packet flow is disconnected on the basis of the reply from the subscriber, the control contents are transmitted to the called VoIP gateway directly or through a control device of the VoIP gateway.

35. A relay router comprising:

monitor means for monitoring a packet flow which passes through the relay router and in which is set a predetermined priority; and

congestion control means for, when congestion is caused by generation of a new packet flow, for executing congestion control for maintaining a state of a packet flow that is set the predetermined priority and that has been establishing before the congestion is caused.

36. The relay router according to claim 35, wherein the congestion control means outputs a congestion notice for changing the priority of the new packet flow into a priority lower than the predetermined priority or disconnecting the new packet flow.

37. The relay router according to claim 35, wherein the monitor means holds a sum total of a used band of at least one packet flow passing through the relay router and set the predetermined priority and determines that congestion is caused when the sum total exceeds a predetermined allowable value due to generation of a new packet flow.

38. The relay router according to claim 37, further comprising:

flow specifying information storage means for storing flow specifying information for specifying a packet flow which passes through the relay router and is set the predetermined priority;

sum total storage means for storing a sum total of a used band of at least one packet flow having the flow specifying information of which is stored in the flow specifying information storage means; and

allowable value storage means for storing an allowable value of a used band by a packet flow set the predetermined priority, and

wherein, when the relay router receives a packet, the monitor means specifies a priority of the packet, when the specified priority is the predetermined priority, the monitor means refers to the flow specifying information storage means, and when the flow specifying information of the packet is not stored in the flow specifying information storage means, the monitor means calculates a used band of the packet flow of the packet, adds the calculated band value to the sum total stored in the sum total storage means, and determines whether the addition result exceeds the allowable value stored in the allowable value storage means or not.

39. The relay router according to claim 38, wherein, when the monitor means determines that the addition result does not exceed the allowable value stored in the allowable vale storage means, the monitor means registers the flow specifying information of the packet in the flow specifying information storage means, and stores the addition result in the sum total storage means as a new sum total.

40. The relay router according to claim 37, wherein all packet flows in which packets are transferred with the predetermined priority are audio packet flows, and

when the relay router receives an audio packet of a new generated audio packet flow, the monitor means calculates a used band of the audio packet flow of the audio packet on the basis of an RTP payload type and an IP packet length included in the audio packet.

41. The relay router according to claim 38, wherein, when changing the priority or disconnecting is executed with regard to a packet flow having the flow specifying information of which is stored in the flow specifying information storage means, the monitor means deletes the flow specifying information of the packet flow from the flow specifying information storage means and subtracts the value of the used band of the packet flow from the sum total stored in the sum total storage means.

42. The relay router according to claim 38, wherein the monitor means checks whether the relay router receives a packet from a packet flow having the flow specifying information of which is stored in the flow specifying information storage means within a predetermined period of time or not, deletes flow specifying information of a packet flow in which a packet is not received within the predetermined period of time from the flow specifying information storage means, and subtracts the value of the used band of the packet flow from the sum total stored in the sum total storage means.