Session Control Relay for Seamless Server Endpoint Switchover

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Solution Overview

Problem

Existing session control methods fail to maintain continuous communication sessions during server endpoint switching, leading to connection disruptions and user inconvenience due to indiscriminate closure of TCP connections by higher-level communication protocols.

Innovation Solution

A session control method that employs a relay process to store control information associating first and second connections, terminates close instruction messages at the relay process, and updates control information to enable switchover without closing connections, allowing continuous use of established connections post-switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a close instruction message is transmitted from the first apparatus to the second apparatus, then the communication session is properly closed, but the TCP connection is unnecessarily closed preventing switchover to a third apparatus

Engineering Contradiction:

Improveswitchover capabilityVSAvoidconnection stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The relay process acts as an intermediary between the first and second apparatuses. It receives close instruction messages from the first apparatus but terminates these messages before they reach the second apparatus, thereby preventing unnecessary connection closures. The relay process maintains the TCP connection stable while enabling switchover to a third apparatus by blocking the close instruction propagation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the close instruction message handling from the normal communication flow by having the relay process specifically terminate these messages. This separates the connection management function from the data transmission function, allowing the TCP connection to remain open for switchover purposes while still enabling proper session closure when needed through control information updates.

Inventive Principle:

Principle #2Taking out (Extraction)

2Duration of action of stationary object

If the relay process terminates close instruction messages, then connection continuity is maintained during switchover, but control information about session closure is lost

Engineering Contradiction:

Improveconnection durationVSAvoidcontrol information

Core Design Contradiction:

Duration of action of stationary objectVSLoss of information

Solution Approach 1:

The relay process serves as an intermediary that not only terminates close instruction messages but also updates control information to reflect the switchover state. This dual function allows the relay to maintain connection continuity while preserving necessary control information about session closure intentions, preventing information loss despite message termination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The relay process implements feedback by updating control information when it terminates close instruction messages. This feedback mechanism ensures that the system maintains awareness of session closure intentions and switchover states, preventing information loss while allowing the connection to remain open for continuity purposes.

Inventive Principle:

Principle #23Feedback

3Device complexity

If stateless communication protocol is used, then connection management is simple, but communication costs increase for frequent bidirectional real-time data transmission

Engineering Contradiction:

Improveconnection management complexityVSAvoidcommunication cost

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent establishes TCP connections in advance and maintains them open for extended periods, performing the connection setup action beforehand rather than creating new connections for each data transmission. This preliminary action reduces the overhead of repeated connection handshakes and reduces communication costs for frequent bidirectional real-time data transmission, while the relay process manages these connections centrally to keep complexity manageable.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10084862B2Session control method and computer-readable storage medium storing computer program

Publication Date: 2018.09.25 FUJITSU LTD

AI summary

A session control method includes storing control information in which a first connection established on a first apparatus side in relation to a relay process is associated with a second connection established on a second apparatus side in relation to the relay process; terminating, when a close instruction message at a communication layer higher than the first and second connections is issued from the first apparatus to the second apparatus, the close instruction message on the relay process and updating the control information; and enabling, when a switchover notice indicating a switch from the first apparatus to a third apparatus is given and the control information indicates the issuance of the close instruction message, a third connection established on the third apparatus side in relation to the relay process and updating the control information in such a manner that the second connection is associated with the third connection.