Methods and devices for controlling the rate of a pull protocol

• US 20100094960A1
• Filed: 10/14/2009
• Published: 04/15/2010
• Est. Priority Date: 10/15/2008
• Status: Active Grant

• Current Assignee: Xenogenic Development Limited Liability Company (Intellectual Ventures LLC)
• Original Assignee: Patentvc Limited
• Inventors: Thieberger, Gil, Zuckerman, Gal
• Granted Patent: US 7,853,710 B2
• Time in Patent Office: Days
• US Class Current: 709/219
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

Methods and devices for controlling the rate of a pull protocol, including the steps of requesting, from a plurality of fractional-storage servers by an assembling device utilizing a fragment pull protocol, erasure-coded fragments at a first rate that is estimated to approximately result in a target fragment reception throughput. And requesting, by the assembling device, additional erasure-coded fragments instead of fragments that have already been requested but have failed to arrive at the assembling device.

Claims

1. ) A method for accumulating erasure-coded fragments, comprising:

requesting from a plurality of fractional-storage servers, by an assembling device utilizing a fragment pull protocol, erasure-coded fragments associated with segments of streaming content, at a controlled rate that enables presentation of the streaming content.

2. ) The method of claim 1, wherein the fragment pull protocol is a fragment pull protocol for high latency, and the fractional-storage servers are CDN servers.

3. ) The method of claim 1, wherein the fragments are requested approximately according to the sequential order of the segments with which the fragments are associated, whereby the resulting accumulation of fragments resembles the accumulation of data using progressive download.

4. ) The method of claim 1, wherein the controlled rate approximately equals the available incoming throughput of the assembling device.

5. ) The method of claim 1, further comprising changing the controlled rate on-the-fly, while accumulating the fragments.

6. ) The method of claim 1, further comprising setting the controlled rate to a minimum rate that still supports presentation of the streaming content, and then gradually increasing the controlled rate until the fragment loss resulting from requesting fragments at the controlled rate reaches a predefined threshold.

7. ) The method of claim 1, further comprising:

monitoring the fragment loss resulting from requesting fragments at the controlled rate; and

gradually decreasing the controlled rate as long as the fragment loss exceeds a predefined threshold.

8. ) The method of claim 1, further comprising:

monitoring the fragment loss resulting from requesting fragments at the controlled rate; and

gradually increasing the controlled rate as long as the fragment loss is below a predefined threshold.

9. ) A method for retrieving erasure-coded fragments comprising:

requesting, from a plurality of fractional-storage servers by an assembling device utilizing a fragment pull protocol, erasure-coded fragments at a first rate that is estimated to approximately result in a target fragment reception throughput; and

requesting, by the assembling device, additional erasure-coded fragments instead of fragments that were already requested but have failed to arrive at the assembling device.

10. ) The method of claim 9, wherein the additional fragments are requested from at least one of the fractional-storage servers utilizing a fragment pull protocol;

and requesting the additional erasure-coded fragments comprises requesting an additional fragment approximately immediately after determining that an already requested fragment has failed to arrive at the assembling device.

11. ) The method of claim 9, wherein the fractional-storage servers are CDN servers, and the fragments are associated with at least one segment of streaming content.

12. ) The method of claim 11, wherein requesting fragments at the first rate comprises requesting the fragments approximately according to the sequential order of the segments with which the fragments are associated.

13. ) The method of claim 11, wherein the fragments are requested in the following order:

requesting at the first rate at least one fragment associated with a certain segment, then requesting at least one of the additional fragments associated with a prior segment, and then requesting at the first rate at least one additional fragment associated with the certain segment.

14. ) The method of claim 13, wherein the target fragment reception throughput approximately equals the available incoming throughput of the assembling device.

15. ) The method of claim 13, wherein the target fragment reception throughput is slightly higher than the rate needed to sustain continuous presentation of the streaming content.

16. ) An apparatus comprising:

an assembling device configured to retrieve erasure-coded fragments from a plurality of fractional-storage servers via multiple fragment pull protocol requests;

wherein the fragment pull protocol requests comprise requests for fragments transmitted at a first rate which is determined approximately according to a target fragment-reception rate, and additional requests for fragments instead of fragments that were already requested but have failed to arrive at the assembling device.

17. ) The apparatus of claim 16, wherein the fragments are associated with approximately sequential segments of streaming content, and the assembling device is configured to issue the requests transmitted at the first rate approximately according to the sequential order of the segments with which the fragments are associated.

18. ) The apparatus of claim 17, wherein the target fragment reception throughput approximately equals the available incoming throughput of the assembling device, and the fractional-storage servers are CDN servers.

19. ) The apparatus of claim 17, wherein the device is configured to monitor the fragment loss, and gradually decrease the first rate as long as the fragment loss exceeds a predefined threshold.

20. ) The apparatus of claim 17, wherein the device is configured to monitor the fragment loss, and gradually increase the first rate as long as the fragment loss is below a predefined threshold.