Ethernet Ring Node Port Pre-Forwarding Timer Mechanism

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Solution Overview

Problem

In Ethernet loop protection systems, a node adjacent to a recovered link may fail to enter a forwarding state in time due to the loss of control protocol messages, leading to traffic loss as it cannot forward data messages promptly.

Innovation Solution

Implement a method where a node adjacent to a failed link sets its port to a pre-forwarding state and starts a timer; if no control protocol message is received within the timer period, the port is released to a forwarding state, ensuring timely data message forwarding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the node adjacent to the recovered link waits for the control protocol message before entering forwarding state, then the network can maintain proper control and avoid loops, but the port cannot forward data messages in time causing traffic loss

Engineering Contradiction:

Improvenetwork control reliabilityVSAvoiddata forwarding speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The port enters pre-forwarding state preliminarily before receiving the control protocol message, allowing data forwarding to start early while still maintaining network safety through the timer mechanism. This preliminary action resolves the contradiction by enabling early data forwarding without compromising control reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The timer mechanism provides beforehand cushioning by setting a time limit on the pre-forwarding state. If the control protocol message is received within the timer period, the port transitions to full forwarding state; if not, the port remains restricted. This cushioning mechanism prevents premature full forwarding while enabling early data transmission.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If the port enters pre-forwarding state immediately upon link recovery, then data forwarding can start early, but the port may forward data messages before receiving control protocol messages causing network loops

Engineering Contradiction:

Improvedata forwarding speedVSAvoidnetwork loop prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The port's forwarding state is made dynamic through the timer mechanism. The port transitions from pre-forwarding state (limited forwarding) to forwarding state (full forwarding) based on whether the control protocol message is received within the timer period. This dynamic adjustment resolves the contradiction by adapting the forwarding behavior to the actual network state.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The timer creates a periodic check mechanism where the system periodically evaluates whether to allow full forwarding based on the arrival of the control protocol message. This periodic evaluation ensures that data forwarding is enabled early while maintaining network safety through time-bounded verification.

Inventive Principle:

Principle #19Periodic action

3Speed

If the control protocol message is sent immediately upon link failure detection, then the master node can quickly notify transmission nodes, but the message may be lost during transmission

Engineering Contradiction:

Improvenotification speedVSAvoidmessage delivery reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The node adjacent to the recovered link performs preliminary action by entering pre-forwarding state and starting the timer before receiving the control protocol message. This preliminary preparation ensures that when the message arrives, the port is already in the correct state to handle it, reducing the impact of message loss or delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The timer mechanism provides feedback by monitoring whether the control protocol message is received within the expected time frame. If the message is lost or delayed beyond the timer period, the system receives feedback and adjusts the port state accordingly, ensuring reliable operation despite message transmission issues.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8570858B2Control method for protecting failure recovery of ethernet ring and ethernet ring nodes

Publication Date: 2013.10.29 ZTE CORP

AI summary

The present invention discloses a method for controlling failure recovery of Ethernet loop protection and an Ethernet loop node. The method comprises: when a node adjacent to a failed link detects recovery of the link, blocking a port just recovered, setting the port to be in a pre-forwarding state and starting a timer, and releasing the port temporarily blocked if the node adjacent to the failed link has not received a control protocol message sent by a master node during a timing period of the timer, and transferring the port from the pre-forwarding state to a forwarding state. The present invention allows a port of a node adjacent to a recovered link to enter into a forwarding state from the pre-forwarding state as early as possible on the premise that a corresponding control protocol message is unable to be received in time.