Method and system for facilitating increased call traffic by reducing signaling load in an emergency mode

• US 6,650,619 B1
• Filed: 03/17/1999
• Issued: 11/18/2003
• Est. Priority Date: 03/17/1999
• Status: Expired due to Fees

• Current Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Original Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Inventors: Schuster, Guido M., Sidhu, Ikhlaq S., Kostas, Thomas J., Grabelsky, David A.
• Primary Examiner(s): Yao, Kwang Bin
• Application Number:
  US09/270,969
• Time in Patent Office: 1,707 Days
• Field of Search: 370/229, 370/230, 370/231, 370/235, 370/236, 370/237, 370/238, 370/352, 370/353, 370/354, 370/355, 370/356, 370/395.2, 370/395.21, 370/401, 370/230.1
• US Class Current: 370/230
• CPC Class Codes: H04Q 3/0025 Provisions for signalling
• CPC Class Codes: H04Q 3/0091 Congestion or overload control

Abstract

A system for increasing call capacity of an internet telephony system in an emergency mode, such as where there is a surge of call requests in a particular region. A management system in the internet telephony system may detect the presence of an actual or potential state of congestion of call traffic and/or signaling traffic. In order to admit a higher rate of call traffic to the telephony system, action is taken to reduce the workload of the signaling system, in order to allow the telephony system to focus more on serving call requests. For example, the signaling system may reduce the rate of signaling request messages processed with respect to requested and ongoing calls and/or reduce the amount of processing involved in handling such messages.

Claims

1. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said telephony system includes a gateway/terminal and a signaling server, said gateway/terminal receiving call requests and responsively transmitting a number of signaling request messages to said signaling server,

wherein modifying said signaling subsystem comprises switching to a mode in which said gateway/terminal does not transmit authorization messages to said signaling server.

2. A method as claimed in claim 1, wherein identifying a state of congestion in said internet telephony system comprises detecting said state of congestion.

3. A method as claimed in claim 1, wherein identifying a state of congestion in said internet telephony system comprises receiving a control signal indicative of said state of congestion.

4. A method as claimed in claim 1, wherein identifying a state of congestion comprises determining that a state of emergency exists.

5. A method as claimed in claim 1, wherein said state of emergency comprises an occurrence of a natural disaster.

6. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising, in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said telephony system includes a gateway/terminal and a signaling server, said gateway/terminal receiving call requests and responsively transmitting a number of signaling request messages to said signaling server,

wherein modifying said signaling subsystem comprises switching to a mode in which said gateway/terminal does not transmit accounting messages to said signaling server.

7. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising, in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said telephony system includes a gateway/terminal and a signaling server, said gateway/terminal receiving call requests and responsively transmitting a number of signaling request messages to said signaling server,

wherein modifying said signaling subsystem comprises switching to a mode in which said signaling subsystem at least temporarily does not perform a predetermined type of call-setup function, said predetermined type of call setup function being selected from the group consisting of admission, authentication and accounting.

8. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising, in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said internet telephony system includes a gateway/terminal and a signaling server, said gateway/terminal receiving call requests and responsively transmitting a number of signaling messages to said signaling server, and said signaling server responsively performing a number of said call set-up functions; and

wherein modifying said signaling subsystem comprises reducing the number of call-setup functions performed by said signaling server in response to the signaling messages,

whereby reducing said signaling workload facilitates expedited admission of calls into said telephony system.

9. A method as claimed in claim 8, wherein said signaling server comprises a gatekeeper.

10. A method as claimed in claim 8, further comprising sending a control signal to an entity in said telephony system, said control signal indicating said state of congestion.

11. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising, in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said signaling subsystem includes a signaling server, said signaling server initiating a number of database queries with respect to each of a plurality of said call requests; and

wherein modifying said signaling subsystem comprises reducing the number of database queries that said signaling server initiates with respect to said plurality of call requests.

12. In a packet switched telephony system including a signaling subsystem operable to perform a plurality of call-setup functions for each of a plurality of call requests, said call-setup functions cooperatively defining a signaling workload associated with each of said plurality of call requests, a method comprising, in combination:

identifying a state of congestion in said telephony system; and

responsively modifying said signaling subsystem to reduce said signaling workload associated with each of at least a plurality of said call requests,

wherein said telephony system includes a plurality of gateway/terminals and at least one signaling server, and wherein a plurality of signaling messages associated with said call request are transmitted between a pair of said gateway/terminals to establish a connection between said pair of gateway/terminals in response to a call request;

said telephony system having a first call-connection mode in which at least a portion of said signaling messages are routed via said signaling server, and a second call-connection mode in said at least a portion of signaling messages are not routed via said signaling server; and

wherein modifying said signaling subsystem to reduce said signaling workload associated with said call request comprises switching from said first call-connection mode to said second call-connection mode,

whereby reducing said signaling workload facilitates expedited admission of calls into said telephony system.

13. In an internet telephony system of the type comprising a gateway/terminal and a gatekeeper, the gateway/terminal receiving call requests and, for each of a plurality of said call requests, the gateway/terminal sending a number of signaling request messages to the gatekeeper, and the gatekeeper responsively processing the signaling request messages to facilitate a call, said number being at least one, a method comprising, in combination:

said gateway/terminal learning of a state of congestion in said internet telephony system; and

said gateway/terminal responsively reducing the number of signaling request messages that it sends to the gatekeeper for each of a plurality of said call requests,

whereby, by reducing the number of signaling request messages sent to the gatekeeper for each of a plurality of call requests, the gatekeeper experiences a reduced processing load per call request and can therefore serve call requests at a higher rate.

14. A method as claimed in claim 13, wherein learning of a state of congestion in said internet telephony system comprises said gateway/terminal detecting said state of congestion.

15. A method as claimed in claim 13, wherein learning of a state of congestion in said internet telephony system comprises said gateway/terminal receiving a control signal indicative of said state of congestion.

16. A method as claimed in claim 15, further comprising a management system sending said control signal to said gateway/terminal in response to a state of congestion in said internet telephony system.

17. A method as claimed in claim 13, wherein said signaling request messages comprise a messages selected from the group consisting of an authorization message, an accounting message, an address translation message and a call connection message.

18. In an internet telephony system comprising a gateway/terminal and a gatekeeper, the gateway/terminal receiving call requests from telephone devices and responsively sending signaling request messages to said gatekeeper, said gatekeeper processing said signaling request messages to facilitate calls associated with said call requests, said gateway/terminal having a first mode in which, in response to each of a plurality of said call requests, said gateway/terminal sends a first number of signaling request messages to said gatekeeper, a method comprising, in combination:

said gateway/terminal learning of a state of congestion in said internet telephony system; and

said gateway/terminal responsively switching from said first mode to a second mode in which, in response to each of said plurality of call requests, said gateway/terminal sends a second number of signaling request messages to said gatekeeper, said second number being less than said first number,

whereby, by sending fewer signaling request messages to said gatekeeper, said gatekeeper may experience a reduced workload and may therefore be able to serve call requests at an increased rate.

19. A method as claimed in claim 18, wherein learning of a state of congestion in said internet telephony system comprises said gateway/terminal detecting said state of congestion.

20. A method as claimed in claim 18, wherein learning of a state of congestion in said internet telephony system comprises said gateway/terminal receiving a control signal indicative of said state of congestion.

21. A method as claimed in claim 20, further comprising a management system sending said control signal to said gateway/terminal in response to a state of congestion in said internet telephony system.

22. A method as claimed in claim 18,

wherein said internet telephony system comprises a plurality of gateway/terminals each receiving call requests and each having said first mode, and

wherein said method further comprises each of a plurality of said gateway/terminals learning of a state of congestion in said internet telephony system and responsively switching to said second mode.

23. A method as claimed in claim 18, wherein said first number of signaling request messages includes an authentication message and said second number of signaling request messages does not include an authentication message.

24. A method as claimed in claim 18, wherein said first number of signaling request messages includes an accounting message and said second number of signaling request messages does not include an accounting message.

25. A method as claimed in claim 18, wherein said first number of signaling request messages includes an address translation message and said second number of signaling request messages does not include an address translation message.

26. A method as claimed in claim 25, wherein, in said second mode, said gateway/terminal admits calls to only one or more predetermined telephone numbers.

27. A method as claimed in claim 26, wherein said one or more predetermined telephone numbers consist of emergency service telephone numbers.

28. A method as claimed in claim 18, wherein, in said first mode, said gateway/terminal gatekeeper-routes call connection messages and, in said second mode, said gateway/terminal directly-routes call connection messages.

29. A method as claimed in claim 18,

wherein sending said first number of signaling request messages to said gatekeeper comprises sending one or more packages of information to said gatekeeper, whereby said gatekeeper interprets said information as said first number of signaling request messages, and

wherein sending fewer than said first number of signaling request messages to said gatekeeper comprises not sending at least a portion of said one or more packages of information to said gatekeeper.

30. A method as claimed in claim 29, wherein said at least a portion of said one or more packages of information comprises calling party information,

whereby said gatekeeper interprets said calling party information as an authentication request and/or as an accounting request.

31. A method as claimed in claim 29, wherein said at least a portion of said one or more packages of information comprises called party information,

whereby said gatekeeper interprets said called party information as an address translation request.

32. A method as claimed in claim 18, wherein sending said first number of signaling request messages to said gatekeeper comprises sending a first set of information to said gatekeeper, whereby said gatekeeper interprets said first set of information as said first number of signaling request messages, and

wherein, in said second mode, said gateway/terminal sends less than said first set of information to said gatekeeper in response to each of said plurality of call requests, whereby said gatekeeper interprets said less than said first set of information as fewer than said first number of signaling request messages.

33. A method as claimed in claim 32,

wherein said first set of information comprises calling party information, whereby said gatekeeper interprets said calling party information as a request to authenticate a calling party and/or to establish accounting for a call, and

wherein, in said second mode, said gateway/terminal does not send said calling party information to said gatekeeper.

34. A method as claimed in claim 32,

wherein said first set of information comprises a called party telephone number, whereby said gatekeeper interprets said called party telephone number as a request to translate said called party telephone number to a network address, and

wherein, in said second mode, said gateway/terminal does not send said called party telephone number to said gatekeeper.

35. An internet telephony system comprising, in combination:

a plurality of telephone devices;

a packet switched network;

a signaling server coupled with said packet switched network;

a gateway coupled with said packet switched network, said gateway receiving call requests from said telephone devices and, in response to said call requests, sending signaling request messages to said signaling server via said packet switched network, said signaling server processing said signaling request messages, whereby processing said signaling request messages defines a load on said signaling server;

said gateway having a first mode in which said gateway sends a first type of signaling request message to said signaling server in response to call requests, and a second mode in which said gateway does not send said first type of signaling request message to said signaling server in response to call requests;

a management system for identifying a state of congestion in said internet telephony system and responsively providing a special control signal to said gateway;

said gateway receiving said special control signal and responsively switching from said first mode to said second mode,

wherein said first type of signaling request message is a message selected from the group consisting of an authorization message, an accounting message, an address translation message, and a call connection message

whereby, said gateway sends fewer signaling request messages to said signaling server in said second mode and thereby reduces said load on said signaling server.

36. An internet telephony system as claimed in claim 35, wherein said first type of signaling request message is an address translation message, and wherein, in said second mode, said gateway limits incoming calls to a predetermined set of telephone numbers.

37. An internet telephony system as claimed in claim 36, wherein the predetermined set of telephone numbers comprises emergency service numbers.

38. An internet telephony system as claimed in claim 37, wherein the predetermined set of telephone numbers consists of emergency service numbers.

39. An internet telephony system as claimed in claim 35, wherein

said first type of signaling request message is a call connection message;

in said first mode, said gateway routes call connection messages via said signaling server; and

in said second mode, said gateway directly routes call connection messages.

40. An internet telephony system as claimed in claim 35, wherein processing said signaling request messages comprises receiving said signaling messages.

41. An internet telephony system as claimed in claim 35, wherein processing said signaling request messages comprises conducting database queries in response to said signaling request messages.

42. An internet telephony system as claimed in claim 35, wherein processing said signaling request messages comprises routing said signaling request messages to a location in said packet switched network.

43. An internet telephony system as claimed in claim 35, wherein the management system comprises a computer system collecting information about call traffic and/or signaling traffic in said telephony system, and wherein identifying a state of congestion in said telephony system comprises said computer system identifying more than a predetermined level of call traffic and/or signaling traffic at one or more locations in said telephony system.

44. An internet telephony system as claimed in claim 35, wherein the management system comprises a human operator viewing call traffic data and/or signaling traffic data at a computer workstation.

45. An internet telephony system as claimed in claim 35, wherein the management system comprises the signaling server, and providing said special control signal to said gateway comprises said signaling server sending the special control signal to the gateway via the packet switched network.

46. An internet telephony system as claimed in claim 35, wherein the management system provides the special control signal to the gateway via the packet switched network.

47. An internet telephony system as claimed in claim 35, wherein the management system comprises a human being.

48. In an internet telephony system of the type comprising a gateway subsystem, a gatekeeper subsystem, and a database subsystem, said gateway subsystem receiving call requests and responsively sending a number of signaling request messages to said gatekeeper subsystem, said gatekeeper subsystem receiving said signaling request messages and responsively sending a number of database request messages to said database subsystem with respect to a plurality of call requests, a method comprising, in combination:

said gatekeeper subsystem learning of a state of congestion in said internet telephony system; and

in response to learning of said state of congestion, said gatekeeper subsystem reducing the number of database request messages that it sends to said database subsystem with respect to said plurality of call requests,

whereby, by reducing the number of database request messages that it sends with respect to said plurality of call requests, said gatekeeper subsystem may expedite admission into said internet telephony system of calls associated with said call requests.

49. A method as claimed in claim 48, wherein learning of a state of congestion in said internet telephony system comprises detecting said state of congestion.

50. A method as claimed in claim 48, wherein learning of a state of congestion in said internet telephony system comprises receiving a control signal indicative of said state of congestion.

51. A method as claimed in claim 50, further comprising a management subsystem detecting a state of congestion in said internet telephony system and responsively providing said control signal to said gatekeeper subsystem.

52. A method as claimed in claim 48, wherein identifying a state of congestion comprises determining that a state of emergency exists.

53. A method as claimed in claim 48, wherein said number of database request messages comprise a first type of database request message selected from the group consisting of an authorization request, an accounting request, and an address translation request.

54. A method as claimed in claim 53, wherein reducing the number of database request messages that it sends to said database subsystem with respect to said plurality of call requests comprises not sending authorization requests with respect to said plurality of call requests.

55. A method as claimed in claim 53, wherein reducing the number of database request messages that it sends to said database subsystem with respect to said plurality of call requests comprises not sending accounting requests with respect to said plurality of call requests.

56. A method as claimed in claim 53, wherein reducing the number of database request messages that it sends to said database subsystem with respect to said plurality of call requests comprises not sending address translation requests with respect to said plurality of call requests.

57. A method as claimed in claim 48, wherein said number of database request messages comprise a first type of database request message selected from the group consisting of an authorization request, an accounting request, and an address translation request.

58. A method as claimed in claim 48, wherein reducing the number of database request messages that it sends to said database subsystem with respect to said plurality of call requests comprises causing said gateway subsystem to reduce said number of signaling request messages that said gateway subsystem sends to said gatekeeper subsystem.

59. A method as claimed in claim 58, wherein causing said gateway subsystem to reduce said number of signaling request messages that said gateway subsystem sends to said gatekeeper subsystem comprises instructing said gateway subsystem to switch from gatekeeper-routed signaling to direct-routed signaling.

60. A signaling server for use in a packet switched telephony system,

said signaling server performing a plurality of signaling functions associated with calls, whereby performing said signaling functions defines a processing burden on said signaling server;

said signaling server having a first mode in which said signaling server is adapted to perform a first set of signaling functions associated with calls, and a second mode in which said signaling server is adapted to perform a second set of signaling functions associated with calls, said second set omitting one or more functions contained in said first set;

said signaling server learning of a state of congestion in said telephony system and responsively switching from said first mode to said second mode,

whereby switching to said second mode reduces said processing burden and thereby enables said signaling server to expedite processing of signaling messages associated incoming calls to said telephony system.

61. A method as claimed in claim 60, wherein learning of a state of congestion in said telephony system comprises said signaling server detecting said state of congestion.

62. A method as claimed in claim 60, wherein learning of a state of congestion in said telephony system comprises said signaling server receiving a control signal indicative of said state of congestion.

63. A method as claimed in claim 62, further comprising a management system detecting a state of congestion in said internet telephony system and responsively sending said control signal to said signaling server.

64. A method as claimed in claim 60, wherein said one or more functions contained in said first set comprises authenticating calling parties with respect to a plurality of call requests,

whereby, in said second mode, said signaling server does not authenticate calling parties with respect to said plurality of call requests.

65. A method as claimed in claim 64, wherein authenticating calling parties comprises querying an authentication database.

66. A method as claimed in claim 62, wherein said one or more functions contained in said first set comprises establishing call accounting with respect to a plurality of call requests,

whereby, in said second mode, said signaling server does not establish call accounting with respect to said plurality of call requests.

67. A method as claimed in claim 66, establishing call accounting comprises querying an accounting database.

68. A method as claimed in claim 60, wherein said one or more functions contained in said first set comprises querying an address mapping database in order to translate telephone numbers to network addresses with respect to a plurality of call requests,

whereby, in said second mode, said signaling server does not query said address mapping database in order to translate telephone numbers to network addresses with respect to said plurality of call requests.

69. A method as claimed in claim 60,

wherein said gateway/terminal receives call requests and responsively sends a number of signaling request messages to said signaling server to facilitate placement of calls associated with said call requests;

wherein said first set of signaling functions comprises processing said signaling request messages, and said one or more functions comprises processing a subset of said signaling request messages,

whereby, in said second mode, said signaling server processes fewer than said number of signaling request messages.

70. A signaling server in an internet telephony system, said signaling server having a first mode in which said signaling server routes call-connection messages being transmitted between an initiating gateway and a terminating gateway, and a second mode in which said signaling server does not participate in routing of call-connection messages between said initiating gateway and said terminating gateway, said signaling server learning of a state of congestion in said internet telephony system, and said signaling server comprising:

a processor;

data storage; and

machine instructions stored in the data storage and executable by the processor, in response to the signaling server learning of the state of congestion, to switch from said first mode to said second mode.

71. The signaling server of claim 70, wherein learning of a state of congestion in said telephony system comprises said signaling server detecting said state of congestion.

72. The signaling server of claim 70, wherein learning of a state of congestion in said telephony system comprises said signal server receiving a control signal indicative of said state of congestion.

73. The signaling server of claim 72, further comprising a management system detecting a state of congestion in said internet telephony system and responsively sending said control signal to said signal server.

74. The signaling server of claim 70, wherein, in response to learning of said state of congestion, said signaling server further instructs said initiating gateway to directly route call-connection messages to said terminating gateway.

75. An internet telephony system comprising, in combination:

a plurality of telephone devices;

a packet switched network;

a signaling subsystem comprising a signaling server and a database system, said signaling server being coupled with said packet switched network and with said database system, said signaling server including a signaling processor for receiving signaling messages and responsively querying said database system, whereby querying said database system defines a load on said signaling subsystem;

a gateway coupled with said packet switched network, said gateway including a telephone interface, a gateway processor and a network interface, said telephone interface receiving call requests from said telephone devices, said gateway processor generating a predetermined request message in response to each of at least a plurality of said call requests, and said network interface sending said predetermined request message to said signaling server via said packet switched network;

said signaling server having a first mode in which said signaling processor queries said database system in response to said predetermined request message and, based on information provided by said database system, said signaling server returns a response message to said gateway;

said signaling server having a second mode in which said signaling server returns a response message to said gateway without querying said database system;

a management system for identifying a state of congestion in said internet telephony system and responsively providing a special control signal to said signaling server;

said signaling server receiving said special control signal and responsively switching from said first mode to said second mode,

whereby, said signaling server reduces its queries to said database system by switching to said second mode and thereby reduces said load on said signaling server.

76. A method for reducing load on a signaling server in an internet telephony system, said internet telephony system comprising a plurality of telephone devices, a packet switched network, and a gateway coupled with said packet switched network, said gateway receiving call requests from said telephone devices and, in response to said call requests, sending predetermined request messages to said signaling server via said packet switched network, said signaling server having a first mode in which said signaling server conducts database queries in response to said predetermined request messages, said method comprising:

identifying a state of congestion in said internet telephony system and responsively switching said signaling server to a second mode in which said signaling server does not conduct database queries in response to said predetermined request messages.