CDN Selection via Bandwidth Ranking and Weighting

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Solution Overview

Problem

Digital content distribution systems face reliability issues due to network congestion and failures, leading to unreliable playback of digital content files.

Innovation Solution

A method that involves receiving a list of content distribution networks from a content directory server, ranking them based on bandwidth, and selecting the highest ranked or weighted CDN for downloading digital content files, with the ability to re-establish playback under fault conditions by buffering and playing content from the selected CDN.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single content distribution network is used to download digital content files, then the system architecture is simple, but the reliability of content playback deteriorates due to network congestion and failures

Engineering Contradiction:
Improvecontent playback reliabilityVSAvoidCDN selection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the CDN selection process into distinct functional components: a content directory server that maintains ranked CDN lists, a bandwidth test mechanism that evaluates CDN performance, and a selection algorithm that chooses optimal CDNs based on tests and rankings. This segmentation allows each component to specialize in one aspect of the problem, improving overall reliability while keeping individual components manageable in complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary actions by pre-ranking multiple CDNs in the content directory server before actual content download. The system performs bandwidth tests and establishes CDN rankings in advance, so when content needs to be downloaded, the selection is already optimized. This preliminary preparation ensures reliable playback without adding complex real-time decision-making during content delivery.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple content distribution networks are tested for bandwidth, then the reliability of content download improves, but the time required to select a CDN increases

Engineering Contradiction:
Improvecontent download reliabilityVSAvoidCDN selection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs bandwidth tests and CDN rankings as preliminary actions that are maintained in the content directory server. Once CDNs are ranked, this information is reused for subsequent content downloads, avoiding repeated full bandwidth tests. This preliminary preparation significantly reduces the time required for CDN selection while maintaining reliable content download through informed choices.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a tiered testing approach where not all CDNs are fully tested for every content download. Instead, the system uses pre-established rankings and may perform limited re-testing or validation. This partial action approach maintains download reliability by relying on proven CDN performance while avoiding the time cost of exhaustive testing for every download request.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If bandwidth tests are performed on all CDNs, then the precision of CDN selection improves, but the energy consumption and system resources increase

Engineering Contradiction:
ImproveCDN bandwidth measurement precisionVSAvoidbandwidth testing energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by performing bandwidth tests selectively rather than on all CDNs for every content request. The system maintains pre-established rankings from previous tests and uses these for selection, performing new tests only when necessary to update rankings or validate performance. This approach maintains measurement precision for CDN selection while significantly reducing energy consumption compared to exhaustive testing of all CDNs.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs bandwidth tests as preliminary actions that establish CDN rankings in advance. These pre-computed rankings are stored and reused for multiple content download operations. By performing the energy-intensive measurement process beforehand rather than repeatedly, the system achieves precise CDN selection capability while amortizing the energy cost over many content deliveries.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If the system maintains a ranked list of multiple CDNs, then the adaptability to network conditions improves, but the complexity of the content directory server increases

Engineering Contradiction:
Improveadaptability to network conditionsVSAvoidcontent directory server complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the adaptability function into specific modular components within the content directory server: a CDN ranking maintenance module that stores and updates CDN performance data, a bandwidth test module that gathers performance metrics, and a selection module that applies ranking information. This segmentation allows the server to adapt to network conditions through structured, maintainable code rather than monolithic complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where bandwidth test results feed into CDN ranking updates, which in turn inform future CDN selections. The system continuously monitors CDN performance through bandwidth tests and adjusts rankings accordingly, creating a closed-loop feedback system. This feedback approach enables adaptability to changing network conditions through systematic updates rather than complex real-time recalculations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2454680B1A digital content distribution system and method
Publication Date: 2018.08.15 NETFLIX INC
  • EP2454680B1 patent drawingFigure 1
  • EP2454680B1 patent drawingFigure 2
  • EP2454680B1 patent drawingFigure 3A

AI summary

One embodiment of the present invention sets forth a technique for selecting a content distribution network (CDN) comprising at least one content server, from a plurality of CDNs, and a playing digital content file from the CDN on a content player. Selecting the CDN is based on a rank order of CDNs, an assigned weight value for each CDN, and a bandwidth measured between the content player and each CDN. Advantageously, a given content player may select a CDN based on prevailing network and CDN loading conditions, thereby increasing overall robustness and reliability when downloading digital content file from a CDN.