Transparent Proxy TCP Switchover via Timer Mechanism

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Solution Overview

Problem

Conventional techniques for TCP connection management in SDN networks result in latency and increased workload when traffic destined for a destination IP address changes paths, as existing TCP connections break and need to be reestablished, impacting end-user experience.

Innovation Solution

Implementing a switchover timer mechanism where the transparent proxy waits for existing TCP connections to end or the timer to expire before transitioning to a new path, allowing for a graceful switchover by relaying new connections and terminating remaining ones, thus minimizing disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traffic path is changed to optimize network performance, then network efficiency is improved, but TCP connections break causing latency and increased workload

Engineering Contradiction:
Improvenetwork efficiencyVSAvoidTCP connection reestablishment latency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by detecting TCP connection establishment in advance and proactively configuring the transparent proxy to relay those connections before path switchover occurs. This allows existing connections to be maintained through the new path without breaking, preventing the need for reestablishment and eliminating the associated latency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transparent proxy acts as an intermediary component between the SDN controller and network traffic. It receives instructions from the SDN controller about path changes and actively manages TCP connections by relaying them through the new path, serving as a mediator that ensures smooth transition without connection breaks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If transparent proxy immediately switches to new path, then network adaptability is improved, but existing TCP connections are terminated

Engineering Contradiction:
Improvepath switching flexibilityVSAvoidTCP connection stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system implements dynamic path switching by monitoring TCP connection states in real-time. When a path change is needed, the transparent proxy dynamically adjusts its behavior to relay existing connections through the new path while allowing new connections to use the optimized route, creating a flexible and adaptive transition process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The SDN controller provides feedback to the transparent proxy about path changes and traffic characteristics. The transparent proxy uses this feedback to make informed decisions about connection management, adjusting its relaying behavior based on real-time network conditions and connection states to maintain reliability during transitions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3529964B1Service aware switch-over of TCP-flows
Publication Date: 2020.05.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3529964B1 patent drawingFigure 1
  • EP3529964B1 patent drawingFigure 2
  • EP3529964B1 patent drawingFigure 3

AI summary

A method is implemented by a transparent proxy to support graceful switchover in a network, where the transparent proxy proxies one or more Transmission Control Protocol (TCP) connections involving a destination Internet Protocol (IP) address. The method includes starting a switchover timer for the destination IP address in response to receiving an instruction from an Application Flow Controller (AFC) to start the switchover timer for the destination IP address and transmitting an indication to the AFC that all of the one or more TCP connections involving the destination IP address that are proxied by the transparent proxy have ended or the switchover timer for the destination IP address has expired in response to a determination that all of the one or more TCP connections involving the destination IP address that are proxied by the transparent proxy have ended or the switchover timer for the destination IP address has expired.