Network architecture for real time delivery of video over lossy networks from remote locations

• US 20060088063A1
• Filed: 10/27/2005
• Published: 04/27/2006
• Est. Priority Date: 10/27/2004
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: ARRIS Group, Inc. (CommScope Holding Company, Inc.)
• Inventors: Krishnamachari, Santhana, Hartung, John, Bai, Junfeng
• Granted Patent: US 7,665,116 B2
• Time in Patent Office: Days
• US Class Current: 370/498
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 45/125 based on throughput or bandwidth
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/3065 for real time traffic
• CPC Class Codes: H04L 45/70 Routing based on monitoring results
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 21/64707 for transferring content from a first network to a second network, e.g. between IP and wireless
• CPC Class Codes: H04N 21/64738 : Monitoring network characteristics, e.g. bandwidth, congestion level data switched network analysis H04L41/14; monitoring functioning in data switched networks H04L43/0817; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64792 : Controlling the complexity of the content stream, e.g. by dropping packets intermediate media network packet handling H04L65/765; proxy provisioning conversion or adaptation for reducing the amount or size of exchanged application data H04L67/5651; negotiation of resources in wireless networks H04W28/16
• CPC Class Codes: H04N 7/17309 : Transmission or handling of upstream communications

Abstract

A method for content delivery comprising transmitting content via a first network to a content aggregation point and transmitting the content from the content aggregation point via a second network to a receiver at the request of the receiver. A system for content delivery comprising a content provider, a content aggregation point operatively coupled to the content provider via a first network wherein the content aggregation point receives content from the content provider, and a receiver operatively coupled to the content aggregation point via a second network wherein the receiver is configured to request content from the content aggregation point. Also disclosed are methods for improving the network functionality through in-band measurement of network statistics, multi-constraint based QoS routing, and back up path determination.

Claims

1. A method for content delivery comprising:

transmitting real-time audio/visual content via a first network to a content aggregation point; and

transmitting the real-time audio/visual content from the content aggregation point via a second network to a receiver at the request of the receiver.

2. The method of claim 1 wherein the real-time audio/visual content is an audio/video stream.

3. The method of claim 1 wherein the first network is a lossy network.

4. The method of claim 1 wherein the second network is a network that meets the transmission requirements for audio/video transmission.

5. The method of claim 1 wherein the content aggregation point buffers the content to recover from losses over the first network.

6. A system for content delivery comprising:

a real-time audio/visual content provider;

a content aggregation point operatively coupled to the content provider via a first network wherein the content aggregation point receives real-time audio/visual content from the content provider; and

a receiver operatively coupled to the content aggregation point via a second network wherein the receiver is configured to request real-time audio/visual content from the content aggregation point.

7. The system of claim 6 wherein the real-time audio/visual content is an audio/video stream.

8. The system of claim 6 wherein the first network is a lossy network.

9. The system of claim 6 the second network is a network that meets the transmission requirements for audio/video transmission.

10. The system of claim 6 wherein the content aggregation point is configured to buffer the content to recover from losses over the first network.

11. A method for in-band measurement of network statistics comprising:

adding a first timestamp from a first local clock in a first node to a first packet and a second packet wherein the first timestamp represents an intended packet transmission time;

adding a second timestamp from the first local clock in the first node to the first packet and the second packet wherein the second timestamp represents an actual packet transmission time;

transmitting the packets from the first node to a second node;

determining a third timestamp wherein the third timestamp represents a packet arrival time from a second local clock at the second node; and

estimating network statistics based on the first, second, and third timestamps.

12. The method of claim 11 further comprising:

adjusting the third timestamp for variable delay.

13. The method of claim 12 wherein the adjusting comprises:

adding a variation in transmit time to the third timestamp; and

adding an estimate of delay jitter.

14. The method of claim 13 further comprising:

adjusting the third timestamp for the difference between the first timestamp and the second timestamp.

15. The method of claim 14 further comprising:

synchronizing the first clock in the first node and the second clock in the second node based on the adjusted third timestamp.

16. The method of claim 11 wherein the packets are video packets.

17. The method of claim 11 wherein the packets are audio packets.

18. The method of claim 11 wherein the packets are multimedia packets.

19. A system for in-band measurement of network statistics comprising:

a first node wherein the first node is configured to add a first timestamp from a first local clock in the first node to a first packet and a second packet wherein the first timestamp represents an intended packet transmission time and the first node is configured to add a second timestamp from the first local clock in the first node to the first packet and the second packet wherein the second timestamp represents an actual packet transmission time;

a second node, operatively coupled to the first node, wherein the second node is configured to receive the first and second packets and the second node is configured to determine a third timestamp wherein the third timestamp represents a packet arrival time from a second local clock at the second node; and

a means for estimating network statistics based on the first, second, and third timestamps.

20. The system of claim 19 wherein the packets are video packets.

21. The system of claim 19 wherein the packets are audio packets.

22. The system of claim 19 wherein the packets are multimedia packets.

23. A method for multi-constraints based QoS routing for content distribution over a network comprising:

filtering a network topology with a first set of QoS constraints resulting in a filtered network topology;

determining a least cost path that satisfies a second set of QoS constraints; and

balancing a network load according to the least cost path.

24. The method of claim 23 wherein the first set of QoS constraints are min(max) QoS constraints.

25. The method of claim 23 wherein the second set of QoS constraints are additive QoS constraints.

26. The method of claim 23 wherein the determining a least cost path comprises performing Dijkstra'"'"'s least cost path routing algorithm.

27. The method of claim 26 further comprising at each searching step in Dijkstra'"'"'s least cost path routing algorithm:

checking if

$\left(\underset{\left(\left(u,v\right)\in <br><br>P\right)}{\sum <br><br>}<br><br>W_i<br><br>\left(u,v\right)<<br><br>L_i\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{foreach}<br><br>\text{\hspace{1em}<br><br>}<br><br>i=1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>m$

over the filtered network topology at each searching step in the Dijkstra algorithm.

28. The method of claim 27 further comprising:

using PATH_LOAD, (P)=MAX<sub>(u,v)ε

P</sub>(Link_load(u,v)), as a cost index to find the least-cost path.

29. The method of claim 28 wherein PATH_LOAD is updated with

30. A method for generating a backup path for a network comprising:

classifying flows over a link; and

determining a backup path for each class.

31. The method of claim 30 wherein flows are classified based on a delay requirement for the flow.

32. The method of claim 31 wherein each class has a similar bandwidth requirement.

33. The method of claim 30 further comprising:

updating the backup path is updated when the network status changes.

34. The method of claim 33 wherein the updating comprises:

determining a delay limit for a new flow;

inserting the new flow into an existing flow list according to the delay limit, making the new flow unclassified;

applying a current classification to the new flow if aggregated bandwidth of any unclassified flows in this class is under a given threshold; and

updating routing information along the backup path with the classification.

35. The method of claim 33 wherein the updating comprises:

determining a delay limit for a new flow;

inserting the new flow into an existing flow list according to the delay limit;

applying a new classification to the new flow if aggregated bandwidth of any unclassified flows in this class is above a given threshold; and

updating routing information along the backup path with the classification.