Opportunistic content delivery using delta coding

摘要

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.

主权项

1. A method for communicating content data from a server optimizer to client optimizers over a communications network, the method comprising: determining, by the server optimizer, to communicate content data to a client optimizer; chunking the content data into a first content block and a set of subsequent content blocks; computing server fingerprints of each of the first content block and the set of subsequent content blocks; communicating a first fingerprint corresponding to the first content block from the server optimizer to the client optimizer; receiving a response package at the server optimizer from the client optimizer, the response package comprising a sequence of client fingerprints, wherein the response package is generated by the client optimizer only when the client optimizer determines that it is one of the first set of client optimizers in relation to the content data and in response to determining that a client fingerprint of the first locally stored content block matches the received first fingerprint, the first locally stored content block having been received and stored by the client optimizer prior to receiving the first server fingerprint from the server optimizer, the first locally stored content block being associated with the sequence of client fingerprints representing a set of next content blocks that were received and stored by the client optimizer directly after receipt of the first locally stored content block in sequence; determining, for each of the set of subsequent content blocks, whether the corresponding server fingerprint indicates equivalence to one of the locally stored content blocks according to its respective client fingerprint received as part of the response package; and communicating a subset of the set of subsequent content blocks from the server optimizer to the client optimizer according to the determination by the server optimizer to communicate the content data to the client optimizer, such that the corresponding server fingerprint of each communicated subsequent content block indicates no equivalence to one of the locally stored content blocks according to its respective client fingerprint.