Systems and method for multicasting a video stream and communications network employing the same

• US 5,892,767 A
• Filed: 03/11/1997
• Issued: 04/06/1999
• Est. Priority Date: 03/11/1997
• Status: Expired due to Term

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Selsius Systems Incorporated (Cisco Systems, Inc.)
• Inventors: Bell, Robert T., Tighe, James R., Forsythe, William C.
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): NGO, RICKY QUOC
• Application Number:
  US08/815,192
• Time in Patent Office: 756 Days
• Field of Search: 370/270, 370/395, 370/396, 370/400, 370/432, 370/486, 348/6, 348/7, 348/8, 348/12, 455/3.1, 455/4.1, 455/5.1, 395/200.31, 395/200.33, 395/200.47, 395/200.48, 395/200.49
• US Class Current: 370/432
• CPC Class Codes: H04N 7/15 Conference systems
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

For use in a communications network having a source and destination endpoint that employs a video transmission protocol in which the destination endpoint of a video stream receives a release command from the source endpoint of the video stream to begin displaying the video stream, the destination endpoint normally receiving the release command only after completion of a capabilities negotiation between the destination endpoint and the source endpoint, a system for, and method of, multicasting the video stream from the source endpoint to at least one destination endpoint. The method includes the steps of: (1) beginning the multicasting of the video stream, (2) ignoring any capabilities messages received from the at least one destination endpoint during the multicasting of the video stream and (3) issuing periodic release commands during the multicasting of the video stream irrespective of receipt times of the ignored capabilities messages, the at least one destination endpoint thereby commanded to begin to display the video stream following a simulation of the capabilities negotiation.

Claims

1. For use in a communications network having a source and destination endpoint that employs a video transmission protocol in which said destination endpoint of a video stream receives a release command from said source endpoint of said video stream to begin displaying said video stream, said destination endpoint normally receiving said release command only after completion of a capabilities negotiation between said destination endpoint and said source endpoint, a method of multicasting said video stream from said source endpoint to at least one destination endpoint, to comprising the steps of:

beginning said multicasting of said video stream;

ignoring any capabilities messages received from said at least one destination endpoint during said multicasting of said video stream; and

issuing periodic release commands during said multicasting of said video stream irrespective of receipt times of said ignored capabilities messages, said at least one destination endpoint thereby commanded to begin to display said video stream following a simulation of said capabilities negotiation.

2. The method as recited in claim 1 wherein said video stream is ITU-T H.261/H.263 encoded.

3. The method as recited in claim 1 wherein said video stream is arranged into ITU-T H.221/H.223 frames.

4. The method as recited in claim 1 wherein said at least one destination endpoint is in a freeze picture state prior to receiving one of said release commands.

5. The method as recited in claim 1 wherein said at least one destination endpoint is released to display said video stream at different times during said multicasting of said video stream.

6. The method as recited in claim 1 wherein said communications network is selected from the group consisting of:

an Asynchronous Transfer Mode (ATM) network;

a Private Switched Network; and

a Public Switched Network.

7. The method as recited in claim 1 wherein said release command is contained within a logical data channel of a frame transmittable through said communications network.

8. The method as recited in claim 1 wherein said video stream is created in real time.

9. The method as recited in claim 1 wherein said method is performed be executing a sequence of executable software instructions.

10. The method as recited in claim 1 wherein said method is embodied, at least in part, as executable code and stored in a storage device.

11. For use in a communications network having a source and destination endpoint that employs a video transmission protocol in which said destination endpoint of a video stream receives a release command from said source endpoint of said video stream to begin displaying said video stream, said destination endpoint normally receiving said release command only after completion of a capabilities negotiation between said destination endpoint and said source endpoint, a system for multicasting said video stream from said source endpoint to at least one destination endpoint, comprising:

a video transmission circuit that begins said multicasting of said video stream, said source endpoint ignoring any capabilities messages received from said at least one destination endpoint during said multicasting of said video stream; and

a command issuance circuit that issues periodic release commands during said multicasting of said video stream irrespective of receipt times of said ignored capabilities messages, said at least one destination endpoint thereby commanded to begin to display said video stream following a simulation of said capabilities negotiation.

12. The system as recited in claim 11 wherein said video stream is ITU-T H.261/H.263 encoded.

13. The system as recited in claim 11 wherein said video stream is arranged into ITU-T H.221/H.223 frames.

14. The system as recited in claim 11 wherein said at least one destination endpoint is in a freeze picture state prior to receiving one of said release commands.

15. The system as recited in claim 11 wherein said at least one destination endpoint is released to display said video stream at different times during said multicasting of said video stream.

16. The system as recited in claim 11 wherein said communications network is selected from the group consisting of:

an Asynchronous Transfer Mode (ATM) network;

a Private Switched Network; and

a Public Switched Network.

17. The system as recited in claim 11 wherein said release command is contained within a logical data channel of a frame transmittable through said communications network.

18. The system as recited in claim 11 wherein said video stream is created in real time.

19. The system as recited in claim 11 wherein said at least one destination endpoint employs a processor and storage device to display said video stream.

20. The system as recited in claim 11 wherein said system is embodied, at least in part, as executable code, stored in a storage device and executed in a processor.

21. A communications network, comprising:

a distribution system;

a plurality of endpoints coupled together via said distribution system for video stream communication thereamong, said plurality of endpoints capable of being alternatively designated as source endpoints or as destination endpoints; and

an operating system and associate driver circuitry that enables use of a video transmission protocol by said source and destination endpoints in which said destination endpoint of a video stream receives a release command from said source endpoint of said video stream to begin displaying said video stream, said destination endpoint normally receiving said release command only after completion of a capabilities negotiation between said destination endpoint and said source endpoint, said operating system and associate driver circuitry, comprising;

a video transmission circuit, associated with said source endpoint, that begins said multicasting of said video stream over said distribution system, said source endpoint ignoring any capabilities messages received from potential destination endpoints during said multicasting of said video stream; and

a command issuance circuit that issues periodic release commands during said multicasting of said video stream irrespective of receipt times of said ignored capabilities messages, multiple destination endpoints thereby commanded to begin to display said video stream following a simulation of said capabilities negotiation, said video transmission circuit and said command issuance circuit thereby cooperating to allow multicasting of said video stream from said source endpoint to said multiple destination endpoints.

22. The communications network as recited in claim 21 wherein said video stream is ITU-T H.261/H.263 encoded.

23. The communications network as recited in claim 21 wherein said video stream is arranged into ITU-T H.221/H.223 frames.

24. The communications network as recited in claim 21 wherein said multiple destination endpoints are in a freeze picture state prior to receiving one of said release commands.

25. The communications network as recited in claim 21 wherein said multiple destination endpoints are released to display said video stream at different times during said multicasting of said video stream.

26. The communications network as recited in claim 21 wherein said communications network is selected from the group consisting of:

an Asynchronous Transfer Mode (ATM) network;

a Private Switched Network; and

a Public Switched Network.

27. The communications network as recited in claim 21 wherein said release command is contained within a logical data channel of a frame transmittable through said communications network.

28. The communications network as recited in claim 21 wherein said video stream is created in real time.

29. The communications network as recited in claim 21 wherein said multiple destination endpoints employ a processor and storage device to display said video stream.

30. The communications network as recited in claim 21 wherein said operating system and associate driver circuitry is embodied, at least in part, as executable code, stored in a storage device and executed in a processor.