Link Aggregation Port Switching for Lossless Traffic Recovery
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Solution Overview
Problem
Existing link aggregation technologies experience packet loss when a port switches from a down state to an up state due to time differences in adding ports to the aggregation group at both ends of a link.
Innovation Solution
A link aggregation port switching method that adds a first port to the aggregation link in the ingress direction and sets its ingress forwarding state to a permitted forwarding state when the port switches from a down state to an up state, and then adds the port to the aggregation link in the egress direction only when the peer end has set its ingress forwarding state to a forward state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a port is quickly added to the aggregation group when switching from down state to up state, then the port can quickly participate in load sharing, but packet loss occurs due to time difference between两端 devices
Solution Approach 1:
The patent applies preliminary action by setting the ingress forwarding state to permitted forwarding state in advance when the port switches from down to up state, before the peer end completes its aggregation group addition. This allows the local device to prepare the forwarding path proactively, reducing packet loss during the synchronization period between两端 devices.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the egress forwarding state based on the synchronization status with the peer end. The egress state transitions from blocked to permitted only after detecting that the peer end has also added the port to its aggregation group, creating a dynamic adaptation mechanism that balances quick recovery with packet loss prevention.
2Productivity
If the port is added to aggregation group immediately, then traffic can be allocated quickly, but traffic cannot pass through the peer end which is still in block state
Solution Approach 1:
The patent segments the forwarding state into two independent dimensions: ingress forwarding state and egress forwarding state. The ingress state can be set to permitted independently to enable quick traffic allocation, while the egress state remains blocked until peer end synchronization is confirmed. This segmentation allows independent control of each direction's forwarding behavior, resolving the contradiction between quick allocation and reliable transmission.
3Loss of time
If ingress forwarding state is set to permitted forwarding state quickly, then the port recovers fast, but packet loss occurs during the asymmetry period
Solution Approach 1:
The patent applies preliminary action by proactively setting the ingress forwarding state to permitted forwarding state as soon as the port transitions from down to up state, without waiting for peer end confirmation. This preliminary configuration minimizes the recovery time by eliminating unnecessary waiting periods, while the egress state control mechanism prevents packet loss by blocking outbound traffic until synchronization is achieved.
Data Source
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AI summary
Provided are a link aggregation port switching method, a network device and a computer storage medium. The method comprises: when a first port of link aggregation switches from a down state to an up state, adding the first port to an aggregation link in an ingress direction, and setting an ingress forwarding state of the first port to be a permitted forwarding state; and when it is determined that the ingress forwarding state is set to be the permitted forwarding state by means of an opposite end of the first port, adding the first port to the aggregation link in an egress direction.