Opportunistic content delivery using delta coding
Systems and methods are described for avoiding redundant data transfers using delta coding techniques when reliably and opportunistically communicating data to multiple user systems. According to embodiments, user systems track received block sequences for locally stored content blocks. An intermediate server intercepts content requests between user systems and target hosts, and deterministically chucks and fingerprints content data received in response to those requests. A fingerprint of a received content block is communicated to the requesting user system, and the user system determines based on the fingerprint whether the corresponding content block matches a content block that is already locally stored. If so, the user system returns a set of fingerprints representing a sequence of next content blocks that were previously stored after the matching content block. The intermediate server can then send only those content data blocks that are not already locally stored at the user system according to the returned set of fingerprints.
1 . A method for receipt of content data at a client device in a communication network, the method comprising:
receiving, at a client device over the communication network, an identifier that identifies a content chunk of the content data from a first intermediate server;
generating a response at the client device in response to receiving the identifier, the response indicating the content chunk and other content chunks associated with the content data that are cached at the client device having been received from a second intermediate server different than the first intermediate server, wherein the other content chunks are different than the content chunk;
sending the response to the first intermediate server over the communication network; and
receiving, at the client device over the communication network, additional content chunks associated with the content data from the first intermediate server, wherein the additional content chunks do not include the content chunk or the other content chunks.
2 . The method of claim 1 , further comprising:
requesting the content data.
3 . The method of claim 2 , wherein the requesting the content data comprises sending a request for the content data from the client device that is received at the first intermediate server.
4 . The method of claim 3 , wherein the first intermediate server intercepts the request sent from the client device.
5 . The method of claim 1 , wherein the first intermediate server chunks the content data into a plurality of content chunks, the content chunk comprises one of the plurality of content chunks, and the other content chunks comprise different content chunks of the plurality of content chucks other than the content chunk.
6 . The method of claim 5 , wherein the plurality of content chunks are determined to ensure that a respective identifier for a given content chunk can be repeatably identified with the respective identifier.
7 . The method of claim 1 , wherein the content chunk comprises at least one of a byte sequence, a file, or a set of files.
8 . The method of claim 1 , wherein the other content chunks are sequential content chunks that were sequentially received from the second intermediate server at the client device after the content chunk.
9 . The method of claim 1 , wherein the identifier identifies candidate matches between the content chunk and a cached content chunk at the client device.
10 . The method of claim 9 , wherein the identifier is created from a content portion of the content chunk.
11 . The method of claim 9 , wherein the identifier comprises a fingerprint of the content chunk.
12 . The method of claim 1 , wherein the identifier comprises header information from a header portion.
13 . The method of claim 12 , wherein the header information indicates that the content data comprises a content stream.
14 . The method of claim 1 , wherein the communication network comprises a cellular communication network.
15 . The method of claim 14 , wherein the communication network comprises a client-server communication link comprising a cellular link.
16 . The method of claim 1 , further comprising:
playing the content data on a media player at the client device, wherein the playing comprises:
playing the content chunk and the other content chunks from a cache at the client device; and
playing the additional content chunks as received from the first intermediate server.
17 . A client device for receipt of content data over a communication network, the client device comprising:
a client cache storing cached content chunks comprising a content chunk and other content chunks received from a first intermediate server;
a user system comprising a client optimizer executed by a hardware processor that: receives an identifier that identifies the content chunk of the content data from a second intermediate server different than the first intermediate server,
determines that the content chuck of the content data and other content chunks of the content data are included in the cached content chunks, and
generates a response in response to receipt of the identifier that indicates the content chunk and the other content chunks of the content data are included in the cached content chucks stored in the client cache; and
a communications subsystem comprising a client-server communication link of the communication network between the client optimizer and the second intermediate server that sends the response to the second intermediate server and, in response, receives additional content chunks of the content data from the second intermediate server, wherein the additional content chunks do not include the content chunk or the other content chunks.
18 . The client device of claim 17 , wherein the communications subsystem requests the content data at the client device.
19 . The client device of claim 18 , wherein the communications subsystem sends a request for the content data from the client device to the second intermediate server.
20 . The client device of claim 19 , wherein the second intermediate server intercepts the request sent from the client device.
21 . The client device of claim 17 , wherein the second intermediate server chunks the content data into a plurality of content chunks and the other content chunks comprise different content chunks of the plurality of content chunks other than the content chunk.
22 . The client device of claim 21 , wherein the plurality of content chunks are determined to ensure that a respective identifier for a given content chuck can be repeatably identified with the respective identifier.
23 . The client device of claim 17 , wherein the content chunk comprises at least one of a byte sequence, a file, or a set of files.
24 . The client device of claim 17 , wherein the other content chunks are sequential content chunks that were sequentially received at the client device after the content chunk.
25 . The client device of claim 17 , wherein the identifier identifies candidate matches between the content chunk and a cached content chunk stored in the client cache.
26 . The client device of claim 25 , wherein the identifier is created from a content portion of the content chunk.
27 . The client device of claim 25 , wherein the identifier comprises a fingerprint of the content chunk.
28 . The client device of claim 17 , wherein the identifier comprises header information from a header portion.
29 . The client device of claim 28 , wherein the header information indicates that the content data comprises a content stream.
30 . The client device of claim 17 , wherein the communication network comprises a cellular communication network.
31 . The client device of claim 30 , wherein the communications subsystem comprises a client-server communication link comprising a cellular link.
32 . The client device of claim 17 , further comprising:
a media player at the client device that plays the content data by playing the content chunk and the other content chunks from the client cache, and playing the additional content chunks as received from the second intermediate server.