Method for allocating data packet transmission among multiple links of a network, and network device and computer program product implementing the method

• US 8,014,400 B2
• Filed: 08/10/2007
• Issued: 09/06/2011
• Est. Priority Date: 08/10/2007
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Zhang, Fan
• Primary Examiner(s): Pham; Chi H
• Assistant Examiner(s): LOPATA, ROBERT J
• Application Number:
  US11/837,367
• Publication Number:
  US 20090041015A1
• Time in Patent Office: 1,488 Days
• Field of Search: 370/394, 370229-238, 709/231, 709/238
• US Class Current: 370/392
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• 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 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]

Abstract

A method for intelligently distributing packets of a data stream to multiple links of a network for simultaneous transmission via the multiple links, and for periodically re-allocating the distribution, achieves higher network throughput. The method has particular application for streaming audio-video traffic on a home local area network that has a source device, like a media server PC, and a destination device, like a digital TV. One of the links is assigned as the primary link (PL), and another link is assigned as a backup link (BL). Periodically a signal is sent from the source device over each link to the destination device and the round-trip travel time (RTT) for the signal and response for each link is measured. The RTT for a link is a good measure of the current end-to-end link status and generally will change during the time that the data stream is being transmitted as a result of certain events, such as traffic load and interference. The RTT on the PL (RTT-PL) and the RTT on the BL (RTT-BL) are used to adjust the allocation of packets simultaneously transmitted on the links.

Claims

1. A method for distributing packets of a data stream in a network having at least two network links, each link connecting a source device to a destination device, the method comprising:

assigning one of said links as a primary link and another of said links as a backup link;

transmitting data stream packets from the source device to the destination device on the primary link using a first set of communications protocols associated with said primary network link;

transmitting a signal from the source device to the destination device on each link and receiving at the source device a return signal from the destination device on each link; and

if the roundtrip time for said signal and return signal on the primary link (RTT-PL) is greater than the roundtrip time for said signal and return signal on the backup link (RTT-BL), then

transmitting a portion of the data stream packets from the source device to the destination device on the backup link using a second set of communications protocols associated with said backup network link, said second set of protocols being different from said first set of protocols.

2. The method of claim 1 wherein each of said links possesses bandwidth and wherein assigning one of said links as a primary link and another of said links as a backup link comprises determining the bandwidth of each link and selecting the primary link to have a greater bandwidth than the backup link.

3. The method of claim 1 wherein transmitting a portion of the data stream packets on the backup link comprises transmitting said portion on the backup link only if RTT-PL is greater than RTT-BL by a predetermined margin.

4. The method of claim 1 wherein transmitting a signal from the source device and receiving a return signal at the source device comprises periodically transmitting said signal and receiving said return signal, and wherein transmitting a portion of the data stream packets on the backup link comprises increasing the portion transmitted on the backup link if the RTT-PL is greater than RTT-BL after each periodic signal transmission and return signal receipt.

5. The method of claim 4 further comprising decreasing the portion transmitted on the backup link if the RTT-PL is less than RTT-BL after each periodic signal transmission and return signal receipt.

6. The method of claim 1 wherein transmitting a signal from the source device to the destination device comprises transmitting an Address Resolution Protocol (ARP) request, and wherein receiving at the source device a return signal from the destination device comprises receiving an ARP reply.

7. The method of claim 1 wherein one of the network links is a powerline communications (PLC) network link.

8. The method of claim 1 wherein one of the network links is a wireless network link.

9. The method of claim 1 wherein the source device is one of a set-top box and a media server, the destination device is a television (TV), and the data stream is an audio-video (AV) stream.

10. A source device capable of transmitting an audio-video (AV) data stream of data packets on a network when the source device is connected to a network that includes a destination device capable of receiving an AV data stream, the source device comprising:

first adapter electronics for interfacing with a wireless network link;

second adapter electronics for interfacing with a wired network link;

a processor;

memory accessible by the processor; and

computer program instructions in the memory and readable by the processor for performing processor-implemented steps when the source device is connected to a destination device via said wireless link and to said destination device via said wired link independent of said wireless link, the steps comprising;

(a) assigning one of said links as a primary link (PL) and the other of said links as a backup link (BL);

(b) transmitting all of the packets of the AV data stream from the source device via the adapter electronics interfaced with the PL;

(c) periodically transmitting a signal to the destination device via each link and receiving at the source device a return signal from the destination device via each link;

(d) periodically measuring the roundtrip time for said signal and return signal on the PL (RTT-PL) and the roundtrip time for said signal and return signal on the BL link (RTT-BL);

(e) if RTT-PL is greater than RTT-BL after a periodic measurement, decreasing the number of packets transmitted from the source device via the adapter electronics interfaced with the PL and increasing the number of packets transmitted from the source device via the adapter electronics interfaced with the BL; and

(f) if RTT-PL is less than RTT-BL after a periodic measurement, decreasing the number of packets transmitted from the source device via the adapter electronics interfaced with the BL and increasing the number of packets transmitted from the source device via the adapter electronics interfaced with the PL.

11. The source device of claim 10 wherein the instructions for performing the step of assigning one of said links as the PL and the other of said links as the BL comprises instructions for determining the bandwidth of each link and selecting as the PL the link having the greater bandwidth.

12. The source device of claim 10 wherein the instructions for performing the step of decreasing the number of packets transmitted from the source device via the adapter electronics interfaced with the PL if RTT-PL is greater than RTT-BL comprises instructions for decreasing the number of packets transmitted from the source device via the adapter electronics interfaced with the PL only if RTT-PL is greater than RTT-BL by a predetermined margin.

13. The source device of claim 10 wherein the instructions for performing the step of transmitting a signal to the destination device via each link and receiving at the source device a return signal from the destination device via each link comprises instructions for transmitting an Address Resolution Protocol (ARP) request and receiving an ARP reply.

14. The source device of claim 10 wherein the source device is one of a set-top box and a media server.

15. A computer program product for implementing a method of transmitting packets of an audio-video (AV) data stream from a source device to a destination device on a network across at least two network links, each link having unique communication protocols, wherein the method is capable of being performed by a computer incorporated in the source device, the computer program product comprising a non-transitory computer-readable medium having computer-executable instructions recorded thereon for implementing the method, the computer-executable instructions comprising:

(a) identifying the links connecting the source device and destination device;

(a) assigning one of said links as a primary link (PL) and another of said links as a backup link (BL);

(b) causing transmission of all of the packets of the AV data stream from the source device via the PL using the protocols associated with the PL;

(c) periodically causing transmission of a signal to the destination device via each link and receipt of a return signal from the destination device via each link;

(d) periodically measuring the roundtrip time for said signal and return signal on the PL (RTT-PL) and the roundtrip time for said signal and return signal on the BL link (RTT-BL);

(e) if RTT-PL is greater than RTT-BL after a periodic measurement, decreasing the number of packets to be transmitted from the source device via the PL and increasing the number of packets to be transmitted from the source device via the BL using the protocols associated with the BL; and

(f) if RTT-PL is less than RTT-BL after a periodic measurement, decreasing the number of packets to be transmitted from the source device via the BL using the protocols associated with the BL and increasing the number of packets to be transmitted from the source device via the PL using the protocols associated with the PL.

16. The computer program product of claim 15 wherein the instructions for assigning one of said links as the PL and another of said links as the BL comprises instructions for determining the bandwidth of each link and selecting as the PL the link having the greater bandwidth.

17. The computer program product of claim 15 wherein the instructions for decreasing the number of packets transmitted from the source device via the PL if RTT-PL is greater than RTT-BL comprises instructions for decreasing the number of packets transmitted from the source device via the PL only if RTT-PL is greater than RTT-BL by a predetermined margin.

18. The computer program product of claim 15 wherein the instructions for causing transmission of a signal to the destination device via each link and receipt of a return signal from the destination device via each link comprises instructions for causing transmission of an Address Resolution Protocol (ARP) request and receipt of an ARP reply.