Methods and systems for requesting fragments without specifying the source address

• US 7,840,679 B2
• Filed: 10/14/2009
• Issued: 11/23/2010
• Est. Priority Date: 10/15/2008
• Status: Active Grant

• Current Assignee: Xenogenic Development Limited Liability Company (Intellectual Ventures LLC)
• Original Assignee: Patentvc Limited
• Inventors: Zuckerman, Gal, Thieberger, Gil
• Primary Examiner(s): WANG, LIANG CHE A
• Application Number:
  US12/579,355
• Publication Number:
  US 20100094961A1
• Time in Patent Office: 405 Days
• Field of Search: 709/217, 709/218, 709/219, 709/223, 709/230, 709/231, 709/226
• US Class Current: 709/226
• 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

A content delivery system which supports fragment requests without specifying the source address, including an assembling device, a relay server, and fractional-storage servers. The assembling device issues a client-request to receive enough erasure-coded fragments to reconstruct a portion of streaming content. The relay server receives the client-request, selects a plurality of fractional-storage servers that together store enough fragments to reconstruct the portion, and transmits, to the fractional-storage servers, fragment pull protocol requests for these sufficient fragments, on behalf of the assembling device. And the fractional-storage servers transmit the requested fragments to the assembling device in response to the fragment requests.

Claims

1. A method for generating fragment requests on behalf of an assembling device, comprising:

receiving, by a relay server from the assembling device, a requirement to receive a certain set of erasure-coded fragments;

wherein erasure-coding denotes a process in which a sequence of erasure-coded fragments are generated from a segment such that the segment can be reconstructed from essentially any subset of the erasure-coded fragments having minimum size not smaller than the size of the segment;

selecting, by the relay server, fractional-storage servers that together meet the requirement;

wherein each fractional-storage server configured to store at least one erasure-coded fragment but less than the minimum amount of fragments or data required to reconstruct the segments; and

transmitting, by the relay server to the selected servers, on behalf of the assembling device, a plurality of requests for the required fragments, wherein the required fragments are to be delivered from the fractional-storage servers to the assembling device not via the relay server.

2. The method of claim 1, wherein the requirement comprises one message comprising a segment identity and the amount of fragments required, associated with that segment.

3. The method of claim 2, wherein the requirement further comprises the identity of streaming content to which the segment belongs, and the erasure-coding is rateless-coding.

4. The method of claim 1, wherein the erasure-coded fragments support source-selection diversity, and the fragments are associated with segments of streaming content;

and further comprising issuing, by the assembling device to the relay server, additional requirements for fragments, such that requirements associated with segments belonging to the beginning of the content are sent by the assembling device before requirements belonging to later segments.

5. The method of claim 1, further comprising requesting, by the assembling device, at least one additional erasure-coded fragment directly from a fractional-storage server.

6. The method of claim 1, wherein the erasure-coded fragments support source-selection diversity, and the fractional-storage servers respond to the fragment requests made on behalf of the assembling device, by transmitting the requested fragments to the assembling device, whereby the identity of the assembling device is made available to the servers.

7. The method of claim 1, wherein the fractional-storage servers are fractional-storage Content Delivery Network (CDN) servers, and the communication from the relay server to the fractional-storage CDN servers, and from the fractional-storage CDN servers to the assembling device are carried over the Internet.

8. The method of claim 1, further comprising identifying potential fractional-storage servers which store fragments relevant to the requirement, from which the fractional-storage servers that together meet the requirement are selected.

9. A method for generating fragment-requests according to a client-request, comprising:

receiving, by a relay server from an assembling device, a client-request to receive erasure-coded fragments usable for reconstructing a portion of streaming content, the portion encompasses significantly less than the entire content, and erasure-coding denotes a process in which a sequence of erasure-coded fragments are generated from a segment such that the segment can be reconstructed from essentially any subset of the erasure-coded fragments having minimum size not smaller than the size of the segment;

selecting, by the relay server, a plurality of fractional-storage servers that together store at least a certain amount of erasure-coded fragments usable to reconstruct the portion, wherein each fractional-storage server configured to store at least one erasure-coded fragment but less than the minimum amount of fragments or data required to reconstruct the segments; and

transmitting, by the relay server to the fractional-storage servers, on behalf of the assembling device, fragment-requests for the certain amount of fragments, wherein the certain amount of fragments is to be delivered from the fractional-storage servers to the assembling device not via the relay server.

10. The method of claim 9, wherein the erasure-coded fragments support source-selection diversity, and the fractional-storage servers respond to the fragment-requests transmitted on behalf of the assembling device by transmitting the requested fragments to the assembling device, whereby the identity of the assembling device is made available to the fractional-storage servers.

11. The method of claim 9, wherein the streaming content comprises a sequence of segments, the portion comprises at least one segment, and the client-request comprises the identity of the at least one segment.

12. The method of claim 9, wherein the streaming content comprises a sequence of segments, the portion comprises segments that span from a first time point to a second time point within the streaming content, and the client-request comprises indicators of the first and second time points, or an indicator of the first time point and a duration.

13. The method of claim 9, wherein the fractional-storage servers are Content Delivery Network (CDN) servers, and the communications from the relay to the fractional-storage servers, and from the fractional-storage servers to the assembling device are carried over the Internet.

14. The method of claim 9, further comprising identifying potential fractional-storage servers which store fragments relevant to reconstructing the portion before selecting the plurality of fractional-storage servers by the relay server.

15. A content delivery system comprising:

an assembling device, a relay server, and fractional-storage servers;

the assembling device configured to issue a client-request to receive a certain amount of erasure-coded fragments usable to reconstruct a portion of streaming content comprising a plurality of segments, the portion encompasses significantly less than all segments;

wherein erasure-coding denotes a process in which a sequence of erasure-coded fragments are generated from a segment such that the segment can be reconstructed from essentially any subset of the erasure-coded fragments having minimum size not smaller than the size of the segment;

the relay server configured to receive the client-request, and transmit to a plurality of fractional-storage servers that together store at least the certain amount of erasure-coded fragments, fragment pull protocol requests for the certain amount of fragments, on behalf of the assembling device;

each fragment pull request associated with a specific segment, and each fractional-storage server configured to store at least one erasure-coded fragment but less than the minimum amount of fragments or data required to reconstruct the segments; and

the fractional-storage servers are further configured to transmit the requested fragments to the assembling device, not via the relay server, in response to the fragment requests.

16. The content delivery system of claim 15, wherein the assembling device is located at a user premises, and the fractional-storage servers are fractional-storage Content Delivery Network (CDN) servers.

17. The content delivery system of claim 15, wherein the relay server is located at the edge of the Internet, and the fractional-storage servers are fractional-storage Content Delivery Network (CDN) servers located close to or on the Internet backbone.

18. The content delivery system of claim 15, wherein the portion is a sub-sequence comprising at least one segment, and the client-request comprises the identity of the sub-sequence.

19. The content delivery system of claim 15, wherein the portion comprises segments that span from a first time point to a second time point within the streaming content, and the client-request comprises indicators of the first and second time points, or an indication of the first time point and a duration.

20. The content delivery system of claim 15, wherein the fragment requests comprise the address of the assembling device, and the erasure-coding is rateless-coding potentially resulting in fragments having a limitless redundancy factor.