Intermediary Device Preserves Source IP During Cache Misses

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Solution Overview

Problem

In data communication networks, maintaining the original source and destination IP addresses of client requests during cache redirection is challenging, as existing systems often modify or lose these addresses, leading to issues with content delivery and network optimization.

Innovation Solution

An intermediary device intercepts client requests, modifies them to check for cached content, and preserves the original IP addresses by using data link layer properties to ensure transparent IP address maintenance throughout the request path, even on cache misses, by including the original source IP address in the request forwarded to and returned from the cache server.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If an intermediary device intercepts client requests to check for cached content, then content delivery speed is improved, but the original source IP address is modified or lost

Engineering Contradiction:
Improvecontent delivery speedVSAvoidoriginal source IP address
Core Design Contradiction:
SpeedVSLoss of information

Solution Approach 1:

The patent uses an intermediary device that acts as a mediator between the client and the cache server. This intermediary preserves the original source IP address by extracting it from the intercepted request, storing it temporarily, and then using it when forwarding the request to the cache server or origin server. This resolves the contradiction by maintaining the IP address information that would otherwise be lost in the caching process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The intermediary device performs preliminary action by extracting and preserving the original source IP address before forwarding the request to the cache server. This advance preservation ensures that the IP address is available for subsequent operations such as cache miss handling and response routing, preventing information loss while enabling cache-based speed improvements.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If an intermediary device modifies client requests for cache redirection, then network traffic optimization is improved, but the integrity of IP addresses is compromised

Engineering Contradiction:
Improvenetwork traffic optimizationVSAvoidintegrity of IP addresses
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The intermediary device serves as a mediator that optimizes network traffic by redirecting requests to the cache server while simultaneously preserving the integrity of IP addresses. It extracts the original source IP address, uses it for cache redirection, and ensures it is maintained throughout the process, thus achieving both traffic optimization and IP address integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The intermediary device temporarily discards the original source IP address from the request stream, processes the request through the cache system, and then recovers the IP address information for proper response routing. This discarding and recovering mechanism enables traffic optimization while maintaining IP address integrity throughout the process.

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If a cache server returns requests on cache miss with modified IP addresses, then cache functionality is improved, but transparent IP address preservation becomes difficult

Engineering Contradiction:
Improvecache functionalityVSAvoidtransparent IP address preservation
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The intermediary device acts as a mediator between the cache server and the origin server, handling the complexity of IP address preservation. When the cache server returns a request on cache miss with modified IP addresses, the intermediary recovers and restores the original source IP address, making the process transparent to the client and origin server while maintaining full cache functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2517417B1Systems and methods for policy based transparent client IP prosecution
Publication Date: 2014.07.16 CITRIX SYSTEMS INC
  • EP2517417B1 patent drawingFigure 1A
  • EP2517417B1 patent drawingFigure 1B
  • EP2517417B1 patent drawingFigure 1C

AI summary

The present disclosure presents systems and methods for maintaining an original source IP address of a request by an intermediary network device despite the source IP address being modified by a cache server during an unfulfilled cache request. An intermediary receives a request from a client to access a destination server via a first transport layer connection. The client request identifies the client's IP address as a source IP address. The intermediary transmits to a cache server, via a second transport layer connection, the client request as a second request modified to include the client IP address of the first request in a header. The intermediary device receives, via a third connection, the second request as a third request from the cache server. The intermediary device obtains the client IP address from the header of the third request and transmits to the server identified in the first request the third request as a fourth request identifying the client IP address as the source IP address.