PSC State Inconsistency Removal in Communication Tunnels
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Solution Overview
Problem
Inconsistencies in Protection State Coordination (PSC) states between two ends of a communication tunnel persist, leading to improper path selection for traffic transmission when both the working and protection paths recover simultaneously, causing nodes to enter inconsistent states and select incorrect paths for traffic routing.
Innovation Solution
A networking device with a transceiver, state detecting unit, inconsistency identifying unit, and inconsistency removing unit that receives PSC messages, detects local PSC states, and changes the state from DNR to Normal if an NR message is received and the local state is DNR, ensuring consistent PSC states and correct path selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PSC state machine based solution is adopted for 1:1 linear protection, then the protection mechanism can coordinate states between two ends, but inconsistency of PSC states between two ends cannot be avoided when both working and protection paths recover simultaneously
Solution Approach 1:
The patent implements a feedback mechanism where nodes exchange PSC state information through messaging. When a node detects that its local state differs from the remote state indicated in received messages, it sends a state inquiry message to the remote node. The remote node responds with its current state, allowing the detecting node to update its state and ensure consistency. This feedback loop resolves the contradiction by maintaining state coordination while adapting to dynamic path recovery scenarios.
2Adaptability or versatility
If independent negotiations for recovery of working and protection paths are performed, then path recovery flexibility is improved, but the possibility of PSC state inconsistency between nodes increases
Solution Approach 1:
The patent employs preliminary action by establishing a state coordination protocol before path recovery negotiations begin. Nodes continuously exchange PSC state messages and maintain state synchronization through predefined transition rules. When independent path recovery negotiations occur, the preliminary state coordination framework ensures that nodes can detect and resolve state inconsistencies, preventing the reliability degradation that would otherwise result from independent negotiations.
3Device complexity
If the PSC state machine ignores remote messages based on local state, then state transition complexity is reduced, but state inconsistency between ends persists
Solution Approach 1:
The patent introduces dynamics by making the message processing behavior adaptive rather than static. Instead of always ignoring remote messages based on fixed local state rules, nodes dynamically adjust their message processing based on state comparison. When a node receives a PSC message, it compares the remote state in the message with its local state, and only ignores messages when states match. When states differ, it processes the message and initiates state synchronization. This dynamic approach maintains low complexity while ensuring state consistency.
Data Source
AI summary
The present invention discloses a method and an associated networking device for eliminating inconsistency of PSC states between two ends of a communication tunnel. The method comprises the steps of: receiving a PSC message from another networking device (S410); detecting a local PSC state of the networking device (S420); determining whether the received PSC message is an NR message and the detected local PSC state is a DNR state (S430); and changing the local PSC state from the DNR state to a Normal state (S440), if it is determined that the received PSC message is an NR message and the detected local PSC state is a DNR state.