Active Link Failure Detection in Single Ring Network Topology
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Solution Overview
Problem
The standard Spanning-Tree Protocol (STP) has a slow convergence time during network topology rebuilding due to its passive wait mechanism, which results in lengthy network downtime when link failures occur.
Innovation Solution
Implementing an active detection method where each node in a single ring network proactively checks for link failures and immediately switches a blocking port's state to forwarding, bypassing the listening and learning states, thereby reducing the time required for topology rebuilding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the standard STP protocol is used for network topology rebuilding, then the network can maintain loop-free topology, but the convergence time is too long (up to 50 seconds)
Solution Approach 1:
The patent applies preliminary action by pre-establishing backup port configurations and pre-calculating alternative paths before link failures occur. When a link failure is detected, the system can immediately activate pre-prepared backup paths without waiting for the standard STP reconvergence process, thereby reducing convergence time while maintaining loop-free topology.
Solution Approach 2:
The patent implements the skipping principle by allowing blocking ports to transition directly to forwarding state when link failures are detected, bypassing the intermediate listening and learning states required by standard STP. This rushed transition significantly reduces the convergence time from 50 seconds to a much shorter duration while still ensuring topology correctness through validation mechanisms.
2Speed
If the forwarding delay is reduced to accelerate topology rebuilding, then the convergence speed improves, but the network may experience temporary loops
Solution Approach 1:
The patent applies feedback by implementing a validation mechanism that continuously monitors network topology changes and provides feedback to control the port state transitions. When a port is switched to forwarding state, the system validates that no loops are created and adjusts subsequent actions based on this feedback, ensuring that convergence speed is improved without sacrificing reliability.
Solution Approach 2:
The patent uses preliminary anti-action by pre-preventing potential loop conditions before they can occur. The system proactively validates alternative paths and blocks potential loop-forming configurations in advance, so when rapid port transitions occur, loops are already prevented rather than allowed to form temporarily.
3Loss of time
If the max age parameter is reduced to detect link failures faster, then the detection speed improves, but the BPDU messages may become invalid too quickly
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the max age parameter based on network conditions and link stability. When links are stable, a longer max age is used to ensure BPDU validity. When rapid detection is needed, the parameter is temporarily reduced, allowing flexible optimization of both detection speed and BPDU reliability according to specific network scenarios.
Data Source
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AI summary
The invention provides a method and a system for rebuilding single ring network topology. In the method, each node in the single ring network detects, at a predetermined time interval, whether the link connected with the root port of the present node is failed (S401); when one node in the single ring network detects a link failure, the node having a blocking port obtains the information that the link failure occurs in the single ring network (S403); and the node having the blocking port switches the state of the port in a blocking state to a forwarding state (S405). With the technical solution provided by the invention, the passive wait for obtaining the link failure can be converted to the active detection for the link failure, and the state of the port in the blocking state is directly switched to the forwarding state. Therefore, the convergence speed is accelerated.