Cache Replacement Policy for Content Distribution Networks

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Solution Overview

Problem

Resource constraints in access networks and increased content storage lead to cache storage resource contention, with cache content retrieval and renewal typically being a reactive process, where new content is cached only after old content expires, inefficiently managing limited storage space.

Innovation Solution

An electronic device in the access network manages a cache by determining and applying content replacement rules, which define policies for replacing objects based on attributes, thresholds, and event triggers, allowing proactive replacement and refreshing of cached content according to specific object types and network conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cache storage capacity is increased to store more content objects, then cache hit rate improves, but cache storage resource contention worsens due to limited access network resources

Engineering Contradiction:
Improvecache storage capacityVSAvoidcache storage resource contention
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by proactively replacing cache content based on predicted future needs rather than waiting for reactive expiration. The network device determines replacement policies in advance, evaluating content attributes and network conditions to replace objects before they would be needed, thus preventing storage contention while maintaining high cache hit rates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cache replacement mechanism is made dynamic by continuously evaluating network conditions, content attributes, and usage patterns. The replacement policy adapts in real-time based on changing network state, allowing the system to optimize cache utilization dynamically rather than using static replacement rules, thereby resolving the contradiction between storage capacity and resource contention.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If reactive caching is used where new content is cached only after old content expires, then cache management simplicity is maintained, but data freshness and access efficiency deteriorate

Engineering Contradiction:
Improvecache management simplicityVSAvoiddata access delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system replaces cache content proactively based on predicted future requirements rather than waiting for expiration. By evaluating content attributes, usage patterns, and network conditions in advance, the system performs preliminary replacement actions that ensure fresh content is available before it would be needed, eliminating access delays while maintaining manageable complexity through automated policy-based decisions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cache replacement mechanism incorporates feedback loops that continuously monitor network conditions, content access patterns, and cache performance metrics. This feedback enables the system to adaptively adjust replacement policies in real-time, optimizing data freshness and access efficiency while maintaining automated management that preserves operational simplicity.

Inventive Principle:
Principle #23Feedback

3Device complexity

If uniform cache replacement policy is applied to all content objects, then policy implementation complexity is reduced, but cache optimization effectiveness deteriorates due to inability to handle different content types

Engineering Contradiction:
Improvepolicy implementation complexityVSAvoidcache optimization effectiveness
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system applies local quality by evaluating and replacing cache objects based on their specific attributes and characteristics rather than using a uniform policy. Different content types, sizes, and access patterns are considered individually, allowing the replacement policy to be optimized for each specific object while maintaining automated decision-making that prevents excessive complexity in policy implementation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cache replacement mechanism utilizes parameter changes by evaluating multiple content parameters (size, type, access frequency, freshness requirements) to determine replacement decisions. The system dynamically adjusts replacement priorities based on changing parameter values, enabling fine-grained optimization of cache utilization without requiring complex manual policy configuration for each content type.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10574778B2Content replacement and refresh policy implementation for a content distribution network
Publication Date: 2020.02.25 CITRIX SYSTEMS INC
  • US10574778B2 patent drawing
  • US10574778B2 patent drawing
  • US10574778B2 patent drawing

AI summary

A method for replacing, refreshing, and managing content in a communication network is provided. The method defines an object policy mechanism that applies media replacement policy rules to defined classes of stored content objects. The object policy mechanism may classify stored content objects into object groups or policy targets. The object policy mechanism may also define metric thresholds and event triggers as policy conditions. The object policy mechanism may further apply replacement policy algorithms or defined policy actions against a class of stored content objects. The media replacement policy rules are enforced at edge content storage repositories in the communication network. A computing device for carrying out the method, and a method for creating, reading, updating, and deleting policy elements and managing policy engine operations, are also provided.