Mux Machine State Synchronization for LACP Packet Loss Prevention
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Solution Overview
Problem
In networks running a Link Aggregation Control Protocol (LACP), packet loss occurs during service traffic transmission due to inconsistencies in the status of aggregation ports between network devices, where one end's aggregation port is in the collecting and distributing state while the other end's is not.
Innovation Solution
A method is implemented where the first network device sets its Mux machine to a PROTECT_WAITING state, sending an LACPDU packet to notify the second network device of its collecting and distributing state, and switches to a COLLECTING_DISTRIBUTING state upon receiving confirmation from the second network device, ensuring both ends are in sync.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network device switches the Mux machine status to COLLECTING_DISTRIBUTING state unilaterally, then the aggregation port can quickly enter collecting and distributing state, but packet loss occurs due to status inconsistency between two ends
Solution Approach 1:
The patent implements a feedback mechanism where network devices send LACPDU packets to notify the peer device of their COLLECTING_DISTRIBUTING state. The device monitors for acknowledgment from the peer and only fully activates the aggregation port when both ends confirm they are in the correct state, preventing unilateral activation that causes packet loss.
Solution Approach 2:
The patent introduces a preliminary notification phase before actual data transmission activation. When one device enters COLLECTING_DISTRIBUTING state, it first sends a notification LACPDU packet to the peer device, allowing the peer to prepare and transition to the same state, ensuring both ends are synchronized before traffic flows.
2Reliability
If the network device waits for peer confirmation before switching to COLLECTING_DISTRIBUTING state, then status consistency is maintained, but link activation time increases
Solution Approach 1:
The patent performs preliminary state transition to COLLECTING_DISTRIBUTING locally, then immediately sends a notification LACPDU to the peer. This allows the local device to be ready for traffic before confirming peer readiness, minimizing wait time while maintaining consistency through the notification-acknowledgment exchange.
Solution Approach 2:
The patent maintains continuous LACPDU packet exchange between peer devices to monitor and maintain state consistency. This continuous communication ensures that both ends remain synchronized without requiring repeated full negotiation sequences, reducing activation time while preserving reliability.
Data Source
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AI summary
A method, a device, and a system for implementing a Mux machine are provided. The method includes: setting, by a first network, a Mux machine on a first aggregation port to be in a PROTECT_WAITING state; when the Mux machine is in the PROTECT _WAITING state, determining, by the first network device, that the first aggregation port is not in a collecting and distributing state, and sending, to a second network device, a first LACPDU packet that is used to notify that the first aggregation port is in the collecting and distributing state; and when determining that a second LACPDU packet that is from the second network device and that is used to indicate that a second aggregation port is in the collecting and distributing state is received, switching, by the first network device, a status of the Mux machine from the PROTECT WAITING state to a COLLECTING DISTRIBUTING state, and setting the first aggregation port to be in the collecting and distributing state. In implementations of this application, Single-port UP of an aggregated link in the Mux machine is detected and processed, thereby alleviating a packet loss generated during service traffic transmission.