Multicast Fast Protection Switching with Minimum Tail Coincidence
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Solution Overview
Problem
Existing multicast technologies require primary and secondary paths to a multicast source to be completely separate in physical topology for fault protection switching, limiting the coverage area of fault protection switching in multicast networks.
Innovation Solution
Determining primary and secondary paths with minimum tail coincidence, where the secondary path is formed by using nodes on a reverse shortest path tree, allowing for replication of multicast traffic and seamless switching in case of primary path failure, even if paths are not completely separate in physical topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary and secondary paths are required to be completely separate in physical topology, then fault protection switching reliability is improved, but device complexity and network configuration difficulty increase
Solution Approach 1:
The patent applies partial separation by requiring paths to be separate only up to a certain point (before the tail coincidence section), rather than requiring complete physical separation throughout the entire path. This partial action maintains sufficient protection while reducing complexity
Solution Approach 2:
The patent creates a universal fast protection switching mechanism that works with both completely separate paths and paths with tail coincidence, making the solution adaptable to various network topologies without requiring complete physical separation in all cases
2Reliability
If primary and secondary paths are completely separate in physical topology, then fault protection capability is improved, but ease of operation and network deployment become more difficult
Solution Approach 1:
The patent requires path separation only partially (until the tail coincidence point), which simplifies network deployment compared to complete separation while maintaining adequate protection capabilities for fast reroute operations
3Adaptability or versatility
If paths with tail coincidence are allowed, then adaptability of fast protection switching is improved, but the risk of simultaneous failure of primary and secondary paths increases
Solution Approach 1:
The patent allows tail coincidence only in the tail section of the paths, maintaining separation for the majority of the path length. This partial approach enables adaptability to various topologies while limiting the exposure to simultaneous failure risks to only the coincident tail section
Solution Approach 2:
The patent introduces an intermediate state where paths are separate for most of their length but may converge at the tail, creating a flexible configuration that balances adaptability with protection against simultaneous failures
Data Source
Figure 1~1a
Figure 2
Figure 2a
AI summary
The present invention provides a method and an apparatus for fast protection switching in multicast, where the method includes: determining a primary path and a secondary path to a source node, where the secondary path and the primary path have minimum tail coincidence; receiving, by using both the primary path and the secondary path, multicast traffic replicated by an upstream neighboring node, and replicating multicast traffic received by the primary path to a downstream neighboring node; and if the primary path is faulty, replicating multicast traffic received by the secondary path to the downstream neighboring node. In the present invention, primary and secondary paths can have minimum tail coincidence, which overcomes a problem that fault protection switching in a multicast network requires that primary and secondary paths existing from a routing node to a multicast source are completely separate in physical topology, and expands an area that the fault protection switching in the multicast network can cover.