Methods and systems capable of switching from pull mode to push mode

• US 20100095016A1
• Filed: 10/15/2009
• Published: 04/15/2010
• Est. Priority Date: 10/15/2008
• Status: Abandoned Application

• Current Assignee: Patentvc Limited
• Original Assignee: Patentvc Limited
• Inventors: Thieberger, Gil, Zuckerman, Gal
• Application Number:
  US12/580,181
• Publication Number:
  US 20100095016A1
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: G06F 16/1834 implemented based on peer-to-peer networks, e.g. gnutella p2p communication protocols H04L67/104
• CPC Class Codes: G06F 16/70 of video data
• CPC Class Codes: H03M 13/37 Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
• CPC Class Codes: H03M 13/3761 using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1021 based on client or server locations
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1091 Interfacing with client-server systems or between P2P systems
• 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 systems capable of switching from pull mode to push mode. The system includes fractional-storage servers using a push protocol to push erasure-coded fragments associated with segments of streaming contents to assembling devices. The servers also provide fragments associated with segments of the same contents in response to fragment pull protocol requests from the assembling devices, wherein enough fragments to enable reconstruction of the segments are transmitted by the servers to the assembling devices using both protocols.

Claims

1. ) A method comprising:

obtaining erasure-coded fragments from a group of fractional-storage servers using a fragment pull protocol;

selecting at least one server from the group according to at least one criterion; and

continuing to obtain erasure-coded fragments from the at least one selected server using a push protocol instead of the previously used fragment pull protocol;

wherein obtaining the fragments via the pull and push protocols enables reconstructing and displaying approximately sequential segments of content while obtaining fragments associated with the following segments.

2. ) The method of claim 1, wherein when starting to display the segments, at least most of the fragments are obtained via the fragment pull protocol, while during at least some of the time thereafter at least most of the fragments are obtained via the push protocol.

3. ) The method of claim 2, wherein the transition from a mostly pull to a mostly push operation is done gradually.

4. ) The method of claim 1, wherein selecting at least one server according to at least one criterion comprises selecting a server having lower load than the average load of the servers in the group.

5. ) The method of claim 1, wherein selecting at least one server according to at least one criterion comprises selecting a server having lower latency than the average latency of the servers in the group.

6. ) The method of claim 1, further comprising gathering information about servers that can potentially be selected as the at least one server, prior to selecting the at least one server.

7. ) The method of claim 6, wherein the information is gathered by registering the latency of servers responding to fragment pull requests.

8. ) The method of claim 1, wherein the fractional-storage servers are CDN servers, and the push protocol comprises a broadcast transmission.

9. ) The method of claim 1, wherein the fractional-storage servers are CDN servers, and the fragments are pushed using a TCP/IP transmission.

10. ) The method of claim 1, wherein the fractional-storage servers are CDN servers, and the fragments are pushed using an RTP stream.

11. ) A method for obtaining fragments, comprising:

retrieving from a group of fractional-storage servers, using a fragment pull protocol, enough erasure-coded fragments to enable reconstruction of at least one segment of streaming content;

selecting at least one server from the group according to at least one criterion; and

continuing to obtain erasure-coded fragments from the at least one selected server using a push protocol, wherein the fragments obtained from the at least one selected server are used to reconstruct the segments following the at least one segment.

12. ) The method of claim 11, wherein the at least one segment comprises enough data to enable continuous presentation of the streaming content, at least up to when a first fragment is obtained using the push protocol.

13. ) The method of claim 11, wherein an assembling device is retrieving the fragments associated with the at least one segment approximately as fast as the bandwidth available to the assembling device allows, and further comprising playing the content approximately as soon as enough segments, out of the at least one segment, are reconstructed to allow doing so.

14. ) The method of claim 11, wherein selecting at least one server according to at least one criterion comprises selecting a server having lower load than the average load of the servers in the group.

15. ) The method of claim 11, wherein selecting at least one server according to at least one criterion comprises selecting a server having lower latency than the average latency of the servers in the group.

16. ) A content delivery system comprising:

fractional-storage servers, configured to use a push protocol to push erasure-coded fragments associated with segments of streaming contents to assembling devices, and provide fragments associated with segments of the same contents in response to fragment pull protocol requests from the assembling devices;

wherein enough fragments to enable reconstruction of the segments are transmitted by the servers to the assembling devices using both protocols.

17. ) The content delivery system of claim 16, wherein the servers are fractional-storage CDN servers, and the assembling devices are located at the user premises.

18. ) The content delivery system of claim 16, wherein each assembling device is configured to obtain fragments by receiving the pushed fragments from the servers and by issuing fragment pull protocol requests to the servers;

whereby the assembling device may obtain all of the fragments needed to reconstruct a single segment using only a push protocol or only a fragment pull protocol.

19. ) The content delivery system of claim 18, wherein the assembling device starts to play content, or to perform a trick play operation on content, by starting to obtain fragments associated with relevant segments using a fragment pull protocol, and then switching to obtaining fragments associated with relevant segments using a push protocol.

20. ) The content delivery system of claim 18, wherein the assembling device may change the ratio Fpull/Fpush on-the-fly to any value between zero and infinity, where Fpull denotes the number of fragments associated with a certain segment that are obtained using a fragment pull protocol, and Fpush denotes the number of fragments associated with the certain segment that are obtained using a push protocol.