Distributed LACP State Machine Segmentation for Switch Stability
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Solution Overview
Problem
Current LACP centralized state machines in distributed communication devices face inefficiency, unreliability, and difficulty in implementing active-standby hot standby, leading to message delivery delays, loss, and increased CPU utilization, especially during active-standby switching, which can result in link disconnection and instability.
Innovation Solution
A distributed method and system for LACP standard state machines, where the receive, periodic transmission, MUX, and transmit machines operate on a line card, and the selection logic operates on a master control, with data synchronization between line cards and the master control, reducing message delivery delays and enhancing stability and reliability during active-standby switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LACP centralized state machine is implemented in distributed system, then protocol control is unified, but message delivery delay increases and reliability decreases
Solution Approach 1:
The patent segments the centralized LACP state machine into distributed state machines located at individual line cards. Each line card independently executes the LACP protocol for its local physical ports, eliminating the need for messages to traverse through the master control to RP and back. This segmentation directly reduces message delivery delay and improves reliability while maintaining protocol control through the selection logic that operates on master control for aggregator selection.
2Reliability
If active-standby hot standby is implemented, then system reliability improves, but CPU utilization increases and message delivery delay increases
Solution Approach 1:
The patent implements preliminary synchronization of LACP state machine data between active and standby RPs before switching occurs. The standby RP pre-loads the operational state information, so when failover is needed, the standby can immediately assume the active role without requiring CPU-intensive data synchronization during the switching event. This preliminary action reduces CPU utilization during active-standby operation and eliminates message delivery delays during switching.
3Ease of operation
If centralized state machine processes all LACP messages, then protocol logic is centralized, but forwarding performance decreases
Solution Approach 1:
The patent extracts the LACP state machine processing functionality from the centralized RP and places it directly at the line cards where physical ports are located. This extraction allows line cards to independently process LACP messages for their local ports without requiring messages to be forwarded to the master control for processing, significantly improving forwarding performance while the master control retains only the selection logic for aggregator selection.
Data Source
AI summary
The present invention provides a distributed method for implementing Link Aggregation Control Protocol (LACP) standard state machines, wherein the method includes: after receiving a message, a physical port transmits it to a receive machine; the receive machine, a periodic transmission machine, a multiplexer (MUX) machine, and a transmit machine are triggered to operate in turn; the selection logic on a master controller is triggered to operate, and the processing of the message is completed according to the physical link selection state of the selection logic on the master controller; wherein, the receive machine, periodic transmission machine, MUX machine, and transmit machine operate on the link card at which the physical port is located, and the selection logic operates on the master controller.