TCP Connection State Synchronization in High-Availability Systems
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Solution Overview
Problem
Current methods for synchronizing TCP connection states in high-availability systems are inefficient, leading to potential route oscillations and increased bandwidth and CPU resource consumption, with a risk of connection state inconsistency during active/standby switching, resulting in reestablishment of TCP connections and degraded system performance.
Innovation Solution
A method where a node requests and updates its connection state information from an opposite node using established connection parameters, including IP addresses and sequence numbers, allowing for timely and reliable active/standby switching by synchronizing connection states without frequent internal synchronization, thereby ensuring consistent state recovery and reducing resource consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active board sends TCP synchronization messages or duplicated messages to the standby board for state synchronization, then the standby board can continue the original TCP connection after switching, but a large amount of bandwidth and CPU resources are consumed, degrading device performance
Solution Approach 1:
The patent extracts the essential connection state information (sequence numbers, acknowledgment numbers, window sizes) from the complex TCP communication process and separates it from the full message duplication approach. By taking out only the critical state parameters rather than duplicating entire TCP messages, the system achieves connection state synchronization with significantly reduced bandwidth and CPU resource consumption while maintaining reliability
Solution Approach 2:
The patent applies local quality by having each board (active and standby) independently maintain and update its own connection state information based on received TCP messages, rather than requiring continuous synchronization communication. The standby board locally processes incoming messages to update its state, reducing the need for intensive inter-board synchronization traffic
2Productivity
If the active board processes heavy service load simultaneously while sending synchronization information to the standby board, then service continuity is maintained, but it is difficult to guarantee simultaneous execution of message transmission and state synchronization, causing time difference and potential connection state inconsistency
Solution Approach 1:
The patent applies preliminary action by having the standby board pre-process incoming TCP messages and update its connection state information in advance, before any potential failover occurs. The standby board maintains its own independent state synchronization mechanism, so when switching occurs, it already has up-to-date connection state without requiring real-time coordination during the critical switching moment
Solution Approach 2:
The patent implements self-service by enabling each board to independently maintain and synchronize its own connection state information without relying on the other board for state updates. The standby board autonomously processes messages and updates its state, and the active board similarly maintains its state, reducing inter-dependency and eliminating the need for complex coordination during failover
3Reliability
If frequent synchronization messages are exchanged between active and standby boards, then connection state consistency is maintained, but system bandwidth and processing capability are consumed, reducing overall system performance
Solution Approach 1:
The patent applies periodic action by having boards exchange synchronization information only at specific intervals or trigger events (such as when connection state actually changes or at predetermined synchronization points), rather than continuously exchanging synchronization messages. This periodic approach maintains connection state consistency while significantly reducing the frequency of synchronization traffic and associated resource consumption
Data Source
AI summary
The present invention discloses a method for synchronizing connection state in data communication, which includes: a node requests connection state information from an opposite node connected with it and the node updates the local connection state according to the connection state information returned by the opposite node. The invention further discloses a communication node using the method. In the invention, by synchronizing the connection state information between a node that may be out of synchronization and its opposite node connected, the problem of connection state synchronization may be solved substantially, and synchronization may be recovered simply by holding the connection. Further, according to the embodiment of the invention, frequent connection state synchronization inside a high-availability system is no longer necessary, so that system bandwidth and processing capability may be saved, and the original connection may be recovered at any moment when an active/standby switching occurs.