Method and apparatus for providing continuous voice and call communications between a data network and a telephony network

• US 6,674,713 B1
• Filed: 02/23/1999
• Issued: 01/06/2004
• Est. Priority Date: 02/23/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bova, Thomas J., Krivoruchka, Theodore S. Jr., Morneault, Kenneth A., Berg, Diane M.
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): MEHRA, INDER P
• Application Number:
  US09/256,688
• Time in Patent Office: 1,778 Days
• Field of Search: 370/216-228, 370/242, 370/244-245, 370/248, 370/252, 370/352, 370/469, 370/401, 370/410, 370/412-413, 370/465-467, 370/522, 370/524, 370/496, 370/241, 370/247, 340/825.01, 714/1, 709/227
• US Class Current: 370/217
• CPC Class Codes: H04M 7/1255 where the switching fabric and the switching logic are decomposed such as in Media Gateway Control
• CPC Class Codes: H04M 7/1285 Details of finding and selecting a gateway for a particular call

Abstract

A method and apparatus are provided for providing continuous voice and call communications between a data network and a telephony network. In one configuration, a first gateway controller that receives the communications from the data network is coupled multiple sessions to a gateway that couples the communications to the telephony network. When the in-use session fails, the communications are automatically switched over from this session to the another session, while maintaining the voice and call communications without interruption, and while ensuring that all messages generated by the gateway are sent to the gateway controller. In another configuration, first and second gateway controllers are designated as Active and Standby. Each of the gateway controllers maintains one or more sessions in communication with the gateway. When the Active gateway controller fails or operator requests a gateway controller switchover, the communications are automatically switched so that communications are directed to the second gateway controller. Accordingly, fault-tolerant voice communication over a packet-switched data network, such as the Internet, is provided. Message queuing may be used to ensure that gateway messages are not lost and reach the gateway controller.

Claims

1. A method of providing continuous voice and call communications between a data network and a telephony network, the method comprising the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initializing to an idle state;

in response to creation of a session of the first and second sessions, entering an out of service state;

when a session of the first and second sessions becomes the primary in service session, entering an in service state; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

2. The method recited in claim 1, wherein the session manager server executes in a logical layer below a signal processing application and above a reliable transport layer.

3. The method recited in claim 1, further comprising the steps of:

when the first session fails, entering a recovery state;

starting a timer set to a predetermined time value; and

returning to the in service state if the first session is restored as the primary session before the timer expires.

4. The method recited in claim 3, further comprising the step of:

remaining in the recovery state if another session is created when in the recovery state.

5. The method recited in claim 3, further comprising the step of:

entering the out of service state if the timer expires and the first session has not been restored as the primary session.

6. The method recited in claim 1, further comprising the steps of:

establishing the first session and the second session between a second gateway controller and the gateway;

providing a second session manager server in the second gateway controller; and

in each of the session manager servers;

initially operating in an idle state;

entering an out of service state from the idle state when the first session is added and becomes in service; and

entering an in service state when the first session becomes the primary in service session.

7. The method recited in claim 6, further comprising the step of notifying the session manager client that the session manager server is active.

8. The method recited in claim 6, further comprising the steps of:

in the session manager client;

initially operating in an idle session state;

entering an out of service state from the idle session state when a session becomes available;

entering an active in service state from the out of service state when an Active notification is received over the first session and when no Standby notification has been received over any session.

9. The method recited in claim 8, further comprising the step of:

entering a standby in service state from the out of service state when a Standby notification is received and when no Active in service session is available.

10. The method recited in claim 8, further comprising the step of:

entering a full in service state from the out of service state upon receiving notifications that the first session is Active and that the second session is Standby.

11. The method recited in claim 10, further comprising the step of:

entering a switchover state from the full in service state upon receiving notification that the second session is Active and no other in service Standby sessions are available.

12. The method recited in claim 1, wherein the session manager client determines whether either of the first and second sessions should be the primary in service session.

13. A method of providing continuous voice and call communications between a data network and a telephony network, the method comprising the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

storing a priority value in association with each session;

wherein the session manager server and the session manager client initialize to an idle state;

in response to creation of a session of the first and second sessions, enter an out of service state;

enter an in service state from the out of service state when the session having the highest priority value becomes the primary in service session;

enter a switchover state from the in service state when the primary in service session fails;

wherein the session manager client

enters a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

14. The method recited in claim 13, further comprising the step of re-entering the in service state from the switchover state when the session having the highest priority again becomes the primary in service session.

15. The method recited in claim 13, further comprising the step of re-entering the switchover state from the degraded state when the session having the highest priority again becomes the primary in service session.

16. The method recited in claim 13, further comprising the steps of:

starting a switchover timer that is set to a pre-determined time value; and

entering the out of service state from the switchover state when no session becomes the primary in service session before the switchover timer expires.

17. The method recited in claim 16, further comprising the steps of:

accumulating a switchover-failure counter each time that the out of service state is entered from the switchover state;

entering an unstable state when the switchover-failure counter is equal to a pre-determined count.

18. The method recited in claim 13, further comprising the step of entering the degraded state from the out of service state when a session having a priority value that is less than the highest priority value becomes the primary in service session.

19. A method of providing continuous voice and call communications between a data network and a telephony network, the method comprising the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

establishing the first session and the second session between a second gateway controller and the gateway, wherein the second gateway controller includes a second session manager server;

in each of the session manager servers;

initially operating in an idle state;

entering an out of service state from the idle state when the first session is added and becomes in service;

entering an in service state when the first session becomes the primary in service session; and

starting a standby notification timer that is set to a pre-determined time period;

in the session manager client;

initially operating in an idle session state;

entering an out of service state from the idle session state when a session becomes available;

entering an active in service state from the out of service state when an Active notification is received over the first session and when no Standby notification has been received over any session;

entering a full in service state from the out of service state upon receiving notifications that the first session is Active and that the second session is Standby; and

entering a switchover state from the full in service state upon receiving notification that the second session is Active and no other in service Standby sessions are available; and

entering the active in service state from the switchover state if the standby notification timer expires before a Standby notification associated with another session is received; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

20. The method recited in claim 19, further comprising the step of:

entering the full in service state from the switchover state upon receiving a Standby notification associated with another session before the standby notification timer expires.

21. The method recited in claim 19, further comprising the steps of:

upon receiving notification that the first session has Standby status, entering the Standby In-Service state from the switchover state; and

notifying the application that the session manager is “

Down”

.

22. The method recited in claim 19, further comprising the step of:

when the session manager client is in the switchover state, queuing messages to be communicated from the session manager client to the session manager server.

23. The method recited in claim 19, further comprising the steps of:

when the session manager client is in the full in service state;

receiving a hold notification;

in response to receiving a hold notification, activating a queue that is stored in association with the session manager client and storing each message of the session manager client directed to the session manager server in the queue.

24. The method recited in claim 23, further comprising the steps of:

when the session manager client is in the active in service state,

receiving a notification to resume sending messages;

in response to the notification to resume sending messages, sending each message in the queue from the session manager client to the session manager server.

25. A method of providing continuous voice and call communications between a packet switched data network and a telephone call signaling network, the method comprising the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephone call signaling network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initially operating the session manager server in an idle state;

in response to creation of a session, operating the session manager server in an out of service state;

when the session becomes the primary in service session, operating the session manager server in an in service state;

when the first session fails, switching over the communications from the first session to the second session.

26. The method recited in claim 25, further comprising the steps of:

when the first session fails, causing the session manager server to enter a recovery state;

starting a timer set to a pre-determined time value; and

returning the session manager server to the in service state if the first session is restored as the primary session before the timer expires.

27. The method recited in claim 26, further comprising the step of:

maintaining the session manager server in the recovery state if another session is created when the session manager server is in the recovery state.

28. The method recited in claim 26, further comprising the step of:

causing the session manager server to enter the out of service state if the timer expires and the first session has not been restored as the primary session.

29. The method recited in claim 25, wherein the session manager client determines whether either of the first and second sessions should be the primary in service session.

30. A method of providing continuous voice and call communications between a packet switched data network and a telephone call signaling network, the method comprising the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephone call signaling network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initially operating the session manager server in an idle state;

in response to creation of a session, operating the session manager server in an out of service state;

when the session becomes the primary in service session, operating the session manager server in an in service state;

storing a priority value in the gateway in association with each session;

causing the session manager client to enter a client in service state from a client out of service state when the session having the highest priority value becomes the primary in service session;

causing the session manager client to enter a switchover state from the client in service state when the in service session fails;

causing the session manager client to enter a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the first session fails, switching over the communications from the first session to the second session.

31. The method recited in claim 30, further comprising the step of causing the session manager client to re-enter the in service state from the switchover state when the session having the highest priority value again becomes the primary in service session.

32. The method recited in claim 30, further comprising the step of causing the session manager client to re-enter the switchover state from the degraded state when the session having the highest priority value again becomes the primary in service session.

33. The method recited in claim 30, further comprising the steps of:

at the gateway, starting a switchover timer that is set to a pre-determined time value; and

causing the session manager client to enter the out of service state from the switchover state when no session becomes the primary in service session before the switchover timer expires.

34. The method recited in claim 33, further comprising the steps of:

accumulating a switchover-failure counter that is stored in the gateway each time that the session manager client enters the out of service state from the switchover state;

causing the session manager client to enter an unstable state when the switchover-failure counter is equal to a pre-determined count.

35. The method recited in claim 30, further comprising the steps of causing the session manager client to enter the degraded state from the out of service state when a session having a priority value that is less than the highest priority value becomes the primary in service session.

36. A computer-readable medium carrying one or more sequences of instructions for providing continuous voice and call communications between a data network and a telephony network, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session;

manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initializing to an idle state;

in response to creation of a session of the first and second sessions, entering an out of service state;

when a session of the first and second sessions becomes the primary in service session, entering an in service state; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

37. A telecommunications system that provides continuous voice and call communications between a data network and a telephony network, comprising:

a first gateway controller that receives the communications from the data network;

a gateway that couples the communications to the telephony network and which is logically coupled to the first gateway controller over the data network;

a computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors in the first gateway controller or the gateway causes the one or more processors to perform the steps of;

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initializes to an idle state;

in response to creation of a session of the first and second sessions, enters an out of service state;

when a session of the first and second sessions becomes the primary in service session, enters an in service state; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

38. An apparatus that is capable of providing voice and call communications between a data network and a telephony network, the apparatus comprising:

means for establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

means for initializing to an idle state;

means for entering an out of service state in response to creation of a session of the first and second sessions;

means for entering an in service state when a session of the first and second sessions becomes the primary in service session; and

means for switching over the communications from the primary in service session to the other session of the first and second sessions, when the primary in service session fails, while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

39. A computer-readable medium carrying one or more sequences of instructions for providing continuous voice and call communications between a data network and a telephony network, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

storing a priority value in association with each session;

wherein the session manager server and the session manager client initialize to an idle state;

in response to creation of a session of the first and second sessions, enter an out of service state;

enter an in service state from the out of service state when the session having the highest priority value becomes the primary in service session;

enter a switchover state from the in service state when t the primary in service session fails;

wherein the session manager client

enters a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the primary in service session fails, switching over the communications from the primary in service session to .the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

40. A telecommunications system that provides continuous voice and call communications between a data network and a telephony network, comprising:

a first gateway controller that receives the communications from the data network;

a gateway that couples the communications to the telephony network and which is logically coupled to the first gateway controller over the data network;

a computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors in the first gateway controller or the gateway causes the one or more processors to perform the steps of;

establishing a first session and a second session between the first gateway controller and the gateway, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

storing a priority value in association with each session;

wherein the session manager server and the session manager client initialize to an idle state;

in response to creation of a session of the first and second sessions, enter an out of service state;

enter an in service state from the out of service state when the session having the highest priority value becomes the primary in service session;

enter a switchover state from the in service state when the primary in service session fails;

wherein the session manager client

enters a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

41. An apparatus that is capable of providing continuous voice and call communications between a data network and a telephony network, the apparatus comprising:

means for establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

means for storing a priority value in association with each session;

wherein the session manager server and the session manager client include means for initializing to an idle state;

means for entering an out of service state in response to creation of a session of the first and second sessions;

means for entering an in service state from the out of service state when the session having the highest priority value becomes the primary in service session;

means for entering a switchover state from the in service state when the primary in service session fails;

wherein the session manager client includes

means for entering a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

means for switching over the communications from the primary in service session to the other session of the first and second sessions, when the primary in service session fails, while maintaining the!voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

42. A computer-readable medium carrying one or more sequences of instructions for providing continuous voice and call communications between a data network and a telephony network, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

establishing the first session and the second session between a second gateway controller and the gateway, wherein the second gateway controller includes a second session manager server;

in each of the session manager servers;

initially operating in an idle state;

entering an out of service state from the idle state when the first session is added and becomes in service;

entering an in service state when the first session becomes the primary in service session; and

starting a standby notification timer that is set to a pre-determined time period;

in the session manager client;

initially operating in an idle session state;

entering an out of service state from the idle session state when a session becomes available;

entering an active in service state from the out of service state when an Active notification is received over the first session and when no Standby notification has been received over any session;

entering a full in service state from the out of service state upon receiving notifications that the first session is Active and that the second session is Standby; and

entering a switchover state from the full in service state upon receiving notification that the second session is Active and no other in service Standby sessions are available; and

entering the active in service state from the switchover state if the standby notification timer expires before a Standby notification associated with another session is received; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

43. A telecommunications system that provides continuous voice and call communications between a data network and a telephony network, comprising:

a first gateway controller that receives the communications from the data network;

a gateway that couples the communications to the telephony network and which is logically coupled to the first gateway controller over the data network;

a computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors in the first gateway controller or the gateway causes the one or more processors to perform the steps of;

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

establishing the first session and the second session between a second gateway controller and the gateway, wherein the second gateway controller includes a second session manager server;

in each of the session manager servers;

initially operating in an idle state;

entering an out of service state from the idle state when the first session is added and becomes in service;

entering an in service state when the first session becomes the primary in service session; and

starting a standby notification timer that is set to a pre-determined time period;

in the session manager client;

initially operating in an idle session state;

entering an out of service state from the idle session state when a session becomes available;

entering an active in service state from the out of service state when an Active notification is received over the first session and when no Standby notification has been received over any session;

entering a full in service state from the out of service state upon receiving notifications that the first session is Active and that the second session is Standby; and

entering a switchover state from the full in service state upon receiving notification that the second session is Active and no other in service Standby sessions are available; and

entering the active in service state from the switchover state if the standby notification timer expires before a Standby notification associated with another session is received; and

when the primary in service session fails, switching over the communications from the primary in service session to the other session of the first and second sessions while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

44. An apparatus that is capable of providing continuous voice and call communications between a data network and a telephony network, the apparatus comprising:

means for establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephony network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

means for establishing the first session and the second session between a second gateway controller and the gateway, wherein the second gateway controller includes a second session manager server;

in each of the session manager servers;

means for initially operating in an idle state;

means for entering an out of service state from the idle state when the first session

is added and becomes in service;

means for entering an in service state when the first session becomes the primary

in service session; and

means for starting a standby notification timer that is set to a predetermined time period;

in the session manager client;

means for initially operating in an idle session state;

means for entering an out of service state from the idle session state when a session becomes available;

means for entering an active in service state from the out of service state when an Active notification is received over the first session and when no Standby notification has been received over any session;

means for entering a full in service state from the out of service state upon receiving notifications that the first session is Active and that the second session is Standby; and

means for entering a switchover state from the full in service state upon receiving notification that the second session is Active and no other in service Standby sessions are available; and

means for entering the active in service state from the switchover state if the standby notification timer expires before a Standby notification associated with another session is received; and

means for switching over the communications from the primary in service session to the other session of the first and second sessions, when the primary in service session fails, while maintaining the voice and call communications and while ensuring that all messages generated by the gateway are sent to the gateway controller.

45. A computer-readable medium carrying one or more sequences of instructions for providing continuous voice and call communications between a packet switched data network and a telephone call signaling network, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephone call signaling network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initially operating the session manager server in an idle state;

in response to creation of a session, operating the session manager server in an out of service state;

when the session becomes the primary in service session, operating the session manager server in an in service state;

storing a priority value in the gateway in association with each session;

causing the session manager client to enter a client in service state from a client out of service state when the session having the highest priority value becomes the primary in service session;

causing the session manager client to enter a switchover state from the client in service state when the in service session fails;

causing the session manager client to enter a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the first session fails, switching over the communications from the first session to the second session.

46. A telecommunications system that provides continuous voice and call communications between a packet switched data network and a telephone call signaling network, comprising:

a first gateway controller that receives the communications from the data network;

a gateway that couples the communications to the telephony network and which is logically coupled to the first gateway controller over the data network;

a computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors in the first gateway controller or the gateway causes the one or more processors to perform the steps of;

establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephone call signaling network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

initially operating the session manager server in an idle state;

in response to creation of a session, operating the session manager server in an out of service state;

when the session becomes the primary in service session, operating the session manager server in an in service state;

storing a priority value in the gateway in association with each session;

causing the session manager client to enter a client in service state from a client out of service state when the session having the highest priority value becomes the primary in service session;

causing the session manager client to enter a switchover state from the client in service state when the in service session fails;

causing the session manager client to enter a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

when the first session fails, switching over the communications from the first session to the second session.

47. An apparatus that is capable of providing continuous voice and call communications between a packet switched data network and a telephone call signaling network, the apparatus comprising:

means for establishing a first session and a second session between a first gateway controller that receives the communications from the data network and a gateway that couples the communications to the telephone call signaling network, wherein the first gateway controller includes a session manager server and the gateway includes a session manager client that is logically coupled to and served by the session manager server;

means for initially operating the session manager server in an idle state;

means for operating the session manager server in an out of service state in response to creation of a session;

means for operating the session manager server in an in service state when the session becomes the primary in service session;

means for storing a priority value in the gateway in association with each session;

means for causing the session manager client to enter a client in service state from a client out of service state when the session having the highest priority value becomes the primary in service session;

means for causing the session manager client to enter a switchover state from the client in service state when the in service session fails;

means for causing the session manager client to enter a degraded state from the switchover state when another session having a lower priority value becomes the primary in service session; and

means for switching over the communications from the first session to the second session when the first session fails.