MPLS Path Selection Using Stability Metrics
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Solution Overview
Problem
In MPLS networks, frequent flapping between working and protection paths leads to excessive processing resource usage and unstable service quality due to frequent state transitions and signaling overhead, especially in scaled protection networks.
Innovation Solution
A method and apparatus that obtain state and stability information of paths between LERs to select a stable path for transmission, reducing undesirable switches and signaling overhead by prioritizing paths based on their state and stability, using a path penalty parameter to determine stability and adjust calculations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PSC unit controls the working path to transmit data in normal state, then the working path provides the primary transmission service, but frequent flapping causes excessive processing resource usage and unstable service quality
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-selecting optimal paths based on historical stability information before flapping occurs. The stability information is obtained in advance through monitoring working paths, and the path selection is determined beforehand using a path selection algorithm that considers both state and stability metrics. This prevents the PSC unit from making frequent reactive switching decisions, thereby reducing processing resource usage while maintaining service quality stability.
2Stability of the object's composition
If the WTR timer is triggered after SF clear event on working path, then the system enters WTR state to prevent flapping, but the traffic may be switched back to working path immediately causing another flap cycle
Solution Approach 1:
The patent implements feedback by continuously monitoring the stability information of paths and using this information to dynamically adjust path selection decisions. The path selection algorithm incorporates feedback from historical stability data to determine whether to switch traffic back to the working path after WTR expires. This feedback mechanism prevents premature switching that would cause flapping cycles, thereby maintaining path state stability without excessive delays.
3Adaptability or versatility
If the working path and protection path have different delay time and loss rate, then each path has distinct transmission characteristics, but frequent traffic swaying between paths makes services requiring stable service quality intolerant
Solution Approach 1:
The patent applies parameter changes by introducing stability information as an additional parameter to the path selection criteria. Instead of solely relying on traditional parameters like delay time and loss rate, the system incorporates stability metrics obtained through continuous monitoring. The path selection algorithm evaluates multiple parameters including state, stability, delay, and loss rate to make informed decisions. This multi-parameter approach maintains flexibility in adapting to different path conditions while ensuring service quality consistency by avoiding frequent switches based on minor parameter variations.
Data Source
AI summary
The embodiments disclose a method and apparatus of selecting a path for transmission from paths between a first LER and a second LER in the MPLS network. The method may comprise: obtaining state information of the paths between the first LER and the second LER, the state information may indicate that a path is in up state or down state; obtaining stability information of at least one of the paths between the first LER and the second LER, the stability information may indicate that a path is stable or unstable; and selecting a path for transmission based on the state information and the stability information.