Delta-Coded Content Delivery Using Fingerprint-Based Block Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional approaches to content delivery via multicast in communications systems face challenges such as redundant data transfers and high network overhead due to the need for maintaining delta coder synchronization and forward error correction, especially when data is distributed opportunistically.
Innovation Solution
A stateless intermediate server uses delta coding techniques to determine which content blocks are already stored at user systems by generating fingerprints of content chunks and comparing them with locally stored blocks, allowing only missing blocks to be sent, thereby reducing redundant data transfers and network overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional multicast approaches are used to deliver content to multiple users, then content can be distributed to multiple users simultaneously, but network overhead increases due to maintaining delta coder synchronization and forward error correction
Solution Approach 1:
The patent extracts and removes redundant data transmissions by using fingerprint comparison to identify content blocks that users already have locally. Instead of transmitting entire content blocks to all users, the system extracts only the missing blocks based on fingerprint matching, thereby eliminating unnecessary network traffic and reducing overhead while maintaining efficient content distribution.
Solution Approach 2:
The patent changes the parameter of data transmission from complete content blocks to selective missing blocks only. By using fingerprint comparison to determine which blocks are missing, the system transforms the transmission parameter from a fixed approach (send all blocks) to a dynamic approach (send only missing blocks), thereby reducing network overhead while maintaining productivity.
2Productivity
If delta coding is applied to multicast stream distribution, then data compression and efficient delivery are achieved, but network overhead for maintaining coder synchronization becomes large
Solution Approach 1:
The patent uses fingerprint copies or hashes of content blocks instead of maintaining actual delta coders and synchronization state. Each user system stores fingerprints of received blocks, and the server compares these fingerprints to determine what to send. This copying approach eliminates the complexity of maintaining synchronized delta coders while preserving the efficiency of selective data transmission.
Solution Approach 2:
The patent introduces fingerprints as an intermediary between the content blocks and the synchronization mechanism. Instead of directly maintaining delta coder state, the system uses fingerprints as a mediator to track received content and determine transmission needs. This intermediary approach simplifies the system by replacing complex state maintenance with simple fingerprint comparison.
3Loss of time
If content is pre-positioned via multicast to remote devices, then future content requests can be fulfilled faster, but redundant data transfers occur when users request content they already have
Solution Approach 1:
The patent implements a feedback mechanism where user systems send information about their locally stored content blocks back to the server. The server uses this feedback (fingerprint information from users) to determine what content to transmit, avoiding redundant transfers of content users already possess. This feedback loop enables the system to adapt transmissions to actual user needs, reducing waste while maintaining fast fulfillment.
Solution Approach 2:
The patent makes the content transmission process dynamic by adjusting what data is sent based on real-time fingerprint comparison results. Instead of a static pre-positioning approach where all content is sent to all users, the system dynamically determines transmission needs by comparing fingerprints, thereby eliminating redundant transfers while maintaining the speed benefit of having content locally available.
Data Source
AI summary
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.