Method, apparatus, system, and computer program product for interruption-free conference calling

• US 7,990,879 B2
• Filed: 03/07/2005
• Issued: 08/02/2011
• Est. Priority Date: 03/05/2004
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Flateby, Paul
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Yuen; Kan
• Application Number:
  US11/072,277
• Publication Number:
  US 20050243741A1
• Time in Patent Office: 2,339 Days
• Field of Search: 370/238, 370/395.5, 370/474, 370216-228, 370/242, 370260-266, 375/240.26, 709/204, 714/774, 348/14, 348 1408- 1411, 348/211.12, 379/158, 379/202.01, 379/205.01
• US Class Current: 370/242
• CPC Class Codes: H04L 12/1863 comprising mechanisms for improved reliability, e.g. status reports arrangements for detecting or preventing errors by carrying supervisory signal the return channel H04L1/16
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04M 2203/2088 Call or conference reconnect, e.g. resulting from isdn terminal portability
• CPC Class Codes: H04M 3/567 Multimedia conference systems
• CPC Class Codes: H04M 7/0027 Collaboration services where a computer is used for data transfer and the telephone is used for telephonic communication
• CPC Class Codes: H04N 7/15 Conference systems

Abstract

The present invention relates to instability problems in circuit switched conferencing, and provides a method for establishing a backup “voice only” telephony link in parallel with a H.320 conference link. The two links between the calling parties is handled as one logical call entity. Audio is muted on the backup voice telephony link when status of the H.320 link is okay. If communication problems are detected on the H.320 link, audio is muted over the H.320 link and switched to the backup voice telephony link instead.

Claims

1. A method for supporting a conference link for communication between two or more endpoints, comprising steps of:

initiating the conference link between the two or more endpoints, said conference link transmitting both video and audio;

establishing, at one of the two or more endpoints, an ISDN (Integrated Services Digital Network) audio-only link between the two or more endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

monitoring, at one of the two or more endpoints, the conference link for predefined errors or events;

switching, at one of the two or more endpoints, communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events is detected in the conference link;

switching, at one of the two or more endpoints, the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

discarding data at an output of a transmitting end-point when the ISDN audio-only link is not in use.

2. The method according to claim 1,

wherein the conference link is an H.320 link comprising a number of ISDN data links merged together.

3. The method according to claim 2,

wherein the step of establishing said ISDN audio-only link further includes indicating a presence of the ISDN audio-only link by inserting a predefined bit pattern in a Res field of an Information Channel Frame.

4. The method according to claim 2, wherein one of said predefined events is an occurrence of a resynchronization process of said conference link.

20. The method of claim 1, wherein the one of the two or more endpoints includes a processor device, a memory, a communication interface, a display device, and a bus configured to communicatively interconnect the processor device, the memory, the communication interface, and the display device.

5. A method for supporting a conference link for communication between two or more endpoints, comprising steps of:

initiating the conference link between the two or more endpoints, said conference link transmitting both video and audio;

establishing, at one of the two or more endpoints, an ISDN (Integrated Services Digital Network) audio-only link between the two or more endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

monitoring, at one of the two or more endpoints, the conference link for predefined errors or events;

switching, at one of the two or more endpoints, communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events is detected in the conference link;

switching, at one of the two or more endpoints, the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

discarding data at an input of a receiving end-point when the ISDN audio-only link is not in use.

6. An apparatus for maintaining a conference link for communication between a plurality of endpoints, comprising:

an initiating unit configured to initiate the conference link between the plurality of endpoints, said conference link being configured to transmit both video and audio;

an establishing unit configured to establish an ISDN (Integrated Service Digital Network) audio-only link between the plurality of endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

a monitoring unit configured to monitor the conference link for predefined errors or events;

a switching unit configured to switch communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events are detected, and to switch the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

a discarding unit configured to discard data at one of an output of a transmitting End-Point and an input of a receiving end-point, when the ISDN audio-only link is not in use.

7. The apparatus of claim 6, wherein the establishing unit is further configured to indicate a presence of the ISDN audio-only link by inserting a predefined bit pattern in a Res field of an Information Channel Frame.

8. The apparatus of claim 6, wherein one of said predefined events is an occurrence of a resynchronization process of said conference link.

9. The apparatus of claim 6, wherein the conference link is an H.320 link comprising a number of ISDN data links merged together.

10. The apparatus of claim 6, further comprising:

a processor device;

a memory;

a communication interface;

a display device; and

a bus configured to communicatively interconnect the processor device, the memory, the communication interface, and the display device.

11. A system for establishing a videoconference, comprising

a first endpoint unit configured to establish a conference link with another endpoint unit, said conference link being configured to transmit both video and audio, said first endpoint unit including

an establishing unit configured to establish an ISDN (Integrated Services Digital Network) audio-only link between the first endpoint unit and another endpoint unit when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio,

a monitoring unit configured to monitor the conference link for predefined errors or events,

a switching unit configured to switch communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events are detected, and to switch the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established, and

a discarding unit configured to discard data at one of an output of a transmitting end-point and an input of a receiving end-point, when the ISDN audio-only link is not in use.

12. The system of claim 11, further comprising:

a second endpoint unit configured establish a second conference link with said first endpoint unit, said second endpoint unit including

a second establishing unit configured to establish a second ISDN audio-only link between the first endpoint unit and another endpoint unit when initiating the second conference link;

a second monitoring unit configured to monitor the second conference link for predefined errors or events; and

a second switching unit configured to switch communication from the second conference link to the second ISDN audio-only link when one or more of said predefined errors or events are detected, and to switch the communication from the second ISDN audio link back to the second conference link when detected errors or events have disappeared or when the second conference link is re-established.

13. The system of claim 11, wherein the establishing unit is further configured to indicate a presence of the ISDN audio link by inserting a predefined bit pattern in a Res field of an Information Channel Frame.

14. The system of claim 11, wherein one of said predefined events is an occurrence of a resynchronization process of said conference link.

15. The system of claim 11, wherein the conference link is an H.320 link comprising a number of ISDN data links merged together.

16. The system of claim 11, wherein the first endpoint unit comprises:

a processor device;

a memory;

a communication interface;

a display device; and

a bus configured to communicatively interconnect the processor device, the memory, the communication interface, and the display device.

17. A non-transitory computer readable storage memory, encoded with instructions, which when executed by a computer, causes the computer to perform a method for supporting a conference link for communication between two or more endpoints, comprising:

initiating the conference link between the two or more endpoints, said conference link transmitting both video and audio;

establishing, at one of the two or more endpoints, an ISDN (Integrated Services Digital Network) audio-only link between the two or more endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

monitoring, at one of the two or more endpoints, the conference link for predefined errors or events;

switching, at one of the two or more endpoints, communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events is detected;

switching, at one of the two or more endpoints, the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

discarding data at an output of a transmitting end-point when the ISDN audio-only link is not in use.

18. The non-transitory computer readable storage memory of claim 17, wherein the one of the two or more endpoints includes a processor device, a memory, a communication interface, a display device, and a bus configured to communicatively interconnect the processor device, the memory, the communication interface, and the display device.

19. An apparatus for maintaining a conference link for communication between a plurality of endpoints, comprising:

means for initiating the conference link between the plurality of endpoints, said conference link transmitting both video and audio;

means for establishing an ISDN (Integrated Service Digital Network) audio-only link between the two or more endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

means for monitoring the conference link for predefined errors or events;

means for switching communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events is detected, and the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

means for discarding data at one of an output of a transmitting end-point and an input of a receiving end-point, when the ISDN audio-only link is not in use.

21. A non-transitory computer readable storage memory, encoded with instructions, which when executed by a computer, causes the computer to perform a method for supporting a conference link for communication between two or more endpoints, comprising:

initiating the conference link between the two or more endpoints, said conference link transmitting both video and audio;

establishing, at one of the two or more endpoints, an ISDN (Integrated Services Digital Network) audio-only link between the two or more endpoints when initiating the conference link,

wherein said conference link transmits both video and audio simultaneously and in parallel with said audio-only link transmitting only audio;

monitoring, at one of the two or more endpoints, the conference link for predefined errors or events;

switching, at one of the two or more endpoints, communication from the conference link to the ISDN audio-only link when one or more of said predefined errors or events is detected in the conference link;

switching, at one of the two or more endpoints, the communication from the ISDN audio-only link back to the conference link when detected errors or events in the conference link have disappeared or when the conference link is re-established; and

discarding data at an input of a receiving end-point when the ISDN audio-only link is not in use.