Method Of Managing The Flow Of Time-Sensitive Data Over Packet Networks

• US 20100321468A1
• Filed: 06/23/2009
• Published: 12/23/2010
• Est. Priority Date: 06/23/2009
• Status: Active Grant

• Current Assignee: Video Solutions Pte. Ltd. (Transpacific IP Group Limited)
• Original Assignee: Magor Communications Corporation (Constellation Software Incorporated)
• Inventors: White, Patrick, Hosseini, Mojtaba
• Granted Patent: US 8,446,823 B2
• Time in Patent Office: Days
• US Class Current: 348/14.08
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/0888 Throughput
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/41 by acting on aggregated flows or links
• CPC Class Codes: H04N 21/2381 Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/2385 Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2625 for delaying content or additional data distribution, e.g. because of an extended sport event

Abstract

A method is disclosed for managing multiple data streams transported over a common communications resource in a packet network, wherein data flowing through the resource travels in both directions, and wherein each stream is subject to data peaks. The round trip delay is determined for each data stream, and the transmission of data peaks in one or more of the data streams is delayed to at least reduce the degree of coincidence in the data peaks of different streams without increasing the maximum round trip delay for the data streams.

Claims

1. A method of managing multiple data streams transported over a common communications resource in a packet network, wherein data flowing through said resource travels in both directions, and wherein each stream is subject to data peaks, comprising:

determining a round trip delay for each data stream; and

delaying transmission of data peaks in one or more of said data streams to at least reduce the degree of coincidence in the data peaks of different streams without increasing the maximum round trip delay for the data streams.

2. A method as claimed in claim 1, wherein said data peaks are delayed so as to remove any coincidence in said data peaks of different streams.

3. A method as claimed in claim 1, wherein the delays introduced into the different data streams are ranked in accordance with the determined round trip delays for each data stream.

4. A method as claimed in claim 1, wherein no delay is introduced into the data stream with the maximum round trip delay.

5. A method as claimed in claim 3, wherein the amount of delay that can be introduced into a data stream is capped at a predetermined value.

6. A method as claimed in claim 3, wherein the round trip delays are monitored over a period of time, and the rank order is changed as necessary to take into account changing round trip delays.

7. A method as claimed in claim 3, wherein the delays are introduced so as to evenly distribute the data peaks in different streams.

8. A method as claimed in claim 1, wherein the data streams flow between a common source and multiple destinations.

9. A method as claimed in claim 1, wherein said data streams represent video streams and said data peaks correspond to I-frames.

10. A method as claimed in claim 9, wherein a period within which the I-frames from all the streams is identified, said period is divided into a plurality of timeslots at least equal in number to the number of data streams, and said I-frames from the different data streams are distributed over said timeslots.

11. A de-synchronizer for reducing packet loss in a packet network wherein multiple data streams are transported over a common communications resource, wherein data flowing through said resource travels in both directions, and wherein each stream is subject to data peaks, comprising:

an interface for communicating with transmitters and receivers for said data streams; and

a processor configured to issue signals, in response to reported round trip delays for the data streams, delaying transmission of data peaks in one or more of said data streams so as to at least reduce the degree of coincidence in the data peaks of different streams without increasing the maximum round trip delay for the data streams.

12. A de-synchronizer as claimed in claim 11, wherein the processor is configured to delay said data peaks so as to remove any coincidence in said data peaks of different streams.

13. A de-synchronizer as claimed in claim 11, wherein said processor is configured to introduce delays into the different data streams that are ranked in accordance with the round trip delays for each data stream.

14. A de-synchronizer as claimed in claim 11, wherein said processor is configured to introduce no delay into the data stream with the maximum round trip delay.

15. A de-synchronizer as claimed in claim 14, wherein the processor is configured to cap the amount of delay that can be introduced into a data stream at a predetermined value.

16. A de-synchronizer as claimed in claim 14, wherein the processor is configured to monitor the round trip delays over a period of time and change the rank order as necessary to take into account changing round trip delays.

17. A de-synchronizer as claimed in claim 14, wherein the processor is configured to introduce delays so as to evenly distribute the data peaks in different streams.

18. A de-synchronizer as claimed in claim 11, wherein said data streams represent video streams and said data peaks correspond to I-frames.

19. A method as claimed in claim 12, further comprising a memory storing a table containing a number of timeslots at least equal to the number of datastreams, and wherein said processor is configured to distribute said I-frames from the different data streams over said timeslots.

20. A video conference apparatus, comprising:

at least one video source;

at least one transmitter for transmitting a transmitted video signal from said at least one source as a data stream;

at least one receiver for receiving a data stream and outputting a received video signal;

at least one display unit for displaying received a received video signal;

a processor responsive to round trip delays for the data streams reported by said receivers to delay transmission of data peaks in one or more of said data streams so as to at least reduce the degree of coincidence in the data peaks of different streams without increasing the maximum round trip delay for the data streams.

21. A video conference apparatus as claimed in claim 20, wherein said processor is configured to introduce delays into the different data streams that are ranked in accordance with the round trip delays for each data stream.

22. A de-synchronizer as claimed in claim 20, wherein said processor is configured to introduce no delay into the data stream with the maximum round trip delay.

23. A de-synchronizer as claimed in claim 20, wherein the processor is configured to cap the amount of delay that can be introduced into a data stream at a predetermined value.