Token-Based Load Balancing for MPTCP Subflow Identification

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Solution Overview

Problem

The Multipath Transport Control Protocol (MPTCP) mechanism fails to work effectively in conventional load balancing systems due to the lack of identification of TCP connections, leading to low communication efficiency, as the server cannot establish subsequent TCP connections successfully due to unrelated 5-tuples.

Innovation Solution

A new load balancing system and method that uses a token-based approach to ensure that MPTCP subflows are forwarded to the same server as the MPTCP primary connection, by calculating a token from the server's key and using it to determine the correct destination server for subsequent connections, maintaining uniform load balancing across TCP subflows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional load balancing mechanism using 5-tuple forwarding is applied to MPTCP connections, then each TCP connection can be forwarded independently, but subsequent TCP connections of the same MPTCP session cannot be identified and forwarded to the same server, causing MPTCP mechanism failure

Engineering Contradiction:
Improveload balancing operationVSAvoidMPTCP connection establishment
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a token as an intermediary element that mediates between the load balancing device and MPTCP connections. The token, generated from the server's key, serves as a unique identifier that enables the load balancing device to correctly identify and forward subsequent TCP connections of the same MPTCP session to the same server, resolving the identification problem without changing the fundamental load balancing operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the forwarding parameter from using only the 5-tuple to using the token as the primary identification parameter. By calculating the server number from the token instead of relying on 5-tuple matching, the system can correctly identify subsequent MPTCP connections and forward them to the appropriate server, maintaining connection consistency across multiple TCP subflows

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If MPTCP protocol is implemented at layer 4 with multipath processing module, then application layer program change is avoided, but the protocol complexity increases and existing load balancing mechanisms cannot handle multiple TCP connections of same MPTCP session

Engineering Contradiction:
Improveimplementation easeVSAvoidprotocol processing complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the complex MPTCP session identification logic from the general load balancing process by introducing a dedicated token-based identification mechanism. The token, derived from the server's key, separates the identification function from the forwarding decision, allowing the load balancing device to handle MPTCP connections with the same simplicity as traditional connections while maintaining session consistency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The token mechanism serves multiple functions: it identifies the server for subsequent connections, maintains session consistency across multiple TCP subflows, and works with existing load balancing infrastructure. This universal approach allows the system to handle both traditional single-TCP connections and MPTCP connections through the same forwarding mechanism, reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If subsequent TCP connections are forwarded to different servers due to different 5-tuples, then load distribution across servers is improved, but the server cannot establish connections successfully due to lack of related information from first TCP connection

Engineering Contradiction:
Improveload distribution efficiencyVSAvoidconnection establishment success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the server's key (obtained during the first TCP connection establishment) is used to generate a token that is returned to the client. This token then serves as feedback for the load balancing device to identify and forward subsequent connections to the same server, ensuring that connection-related information is preserved and the MPTCP session can be successfully established across multiple TCP connections

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3595265B1Load balancing system, method, and device
Publication Date: 2022.12.07 HUAWEI TECH CO LTD
  • EP3595265B1 patent drawingFigure 1
  • EP3595265B1 patent drawingFigure 2A
  • EP3595265B1 patent drawingFigure 2B

AI summary

This application discloses a load balancing system, method, and apparatus, so as to resolve a problem of low communication efficiency in an existing load balancing mechanism. The method includes: receiving, by a load balancing device, a first message that is sent by a client and that is used to request to establish a first TCP connection; sending the first message to a server; receiving a second message that is sent by the client and that is used to request to establish a second TCP connection; and determining, based on a token of the server included in the second message, that a destination device of the second message is the server, and sending the second message to the server, so as to establish the second TCP connection between the client and the server. In this way, multipath transmission control can be implemented in a load balancing mode, thereby improving communication efficiency.