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

• US 20050243741A1
• Filed: 03/07/2005
• Published: 11/03/2005
• Est. Priority Date: 03/05/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Flateby, Paul
• Granted Patent: US 7,990,879 B2
• Time in Patent Office: Days
• US Class Current: 370/260
• 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 one or more endpoints, comprising steps of:

establishing an ISDN audio link between the one or more endpoints when initiating the conference link;

monitoring the conference link for predefined errors or events;

switching communication from the conference link to the ISDN audio link when one or more of said predetermined errors or events is detected; and

switching the communication from the ISDN audio link back to the conference link when detected errors or events have disappeared or when the conference link is re-established.

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 link further includes indicating a presence of the ISDN audio link by inserting a predefined bit pattern in a Res field of an Information Channel Frame.

4. The method according to claim 1, further comprising a step of discarding data at an output of a transmitting end-point when the ISDN audio link is not in use.

5. The method according to claim 1, further comprising a step of discarding data at an input of a receiving end-point when the ISDN audio link is not in use.

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

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

an establishing unit configured to establish an ISDN audio link between the endpoints when initiating the conference link;

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

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

8. The apparatus of claim 7, 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.

9. The apparatus of claim 7, further comprising:

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 link is not in use.

10. The apparatus of claim 7, wherein one of said predefined events is an occurrence of a resynchronization process of said conference link.

11. The apparatus of claim 7, wherein the conference link is an H.320 link comprising a number of ISDN data links merged together.

12. A system for establishing a videoconference, comprising

a first endpoint unit configured to establish conference link with another endpoint unit;

said first endpoint unit including

an establishing unit configured to establish an ISDN audio link between the first endpoint unit and another endpoint unit when initiating the conference link;

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

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

13. The system of claim 12, further comprising:

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

an establishing unit configured to establish an ISDN audio link between the first endpoint unit and another endpoint unit when initiating the conference link;

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

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

14. The apparatus of claim 12, 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.

15. The apparatus of claim 12, further comprising:

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 link is not in use.

16. The apparatus of claim 12, wherein one of said redefined events is an occurrence of a resynchronization process of said conference link.

17. The apparatus of claim 12, wherein the conference link is an H.320 link comprising a number of ISDN data links merged together.

18. A computer program product storing instructions for execution on a computer

system, which when executed by the computer system, causes the computer system to perform steps of:

establishing an ISDN audio link between the one or more endpoints when initiating the conference link;

monitoring the conference link for predefined errors or events;

switching communication from the conference link to the ISDN audio link when one or more of said predetermined errors or events is detected; and

switching the communication from the ISDN audio link back to the conference link when detected errors or events have disappeared or when the conference link is re-established.

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

means for establishing an ISDN audio link between the one or more endpoints when initiating the conference link;

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

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