Bidirectional Circular Path Connectivity Checking in Communication Networks
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Solution Overview
Problem
Current OAM functions in MPLS and MPLS-TP networks cannot effectively check the connectivity of bidirectional circular protection paths, particularly those without predefined source or destination nodes, and require modifications to support additional TLV fields for proper TTL setting in reply packets.
Innovation Solution
A method for checking connectivity of bidirectional circular paths in communication networks, where any MIP can initiate connectivity check packets with a set TTL field based on topology information, and respond with autonomous TTL setting without additional information, allowing connectivity verification along counter-rotating paths without requiring protocol modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OAM functions are used to check connectivity of bidirectional circular protection paths, then connectivity verification is enabled, but the existing OAM functions cannot properly handle paths without predefined source or destination nodes
Solution Approach 1:
The patent inverts the traditional OAM approach by allowing any MIP on the circular path to initiate connectivity checks, rather than requiring fixed source/destination MEPs. The check packets traverse the path in one direction and return in the opposite direction, enabling verification of circular protection paths without predefined endpoints.
Solution Approach 2:
The patent makes MIPs universal by enabling them to both forward user traffic and initiate OAM connectivity checks. This multi-functionality allows any node on the circular path to perform verification, eliminating the need for specialized MEP configurations and making the system adaptable to circular topologies.
2Measurement precision
If additional TLV fields are added to OAM packets for proper TTL setting in reply packets, then connectivity check accuracy is improved, but protocol complexity increases
Solution Approach 1:
The patent implements self-service by having the target MIP autonomously determine the return path TTL based on topology information it already possesses, rather than relying on additional TLV fields from the source. This eliminates the need for protocol modifications while maintaining measurement precision.
3Ease of operation
If connectivity checks are initiated from a single source node, then the check process is simplified, but the ability to verify circular paths without predefined endpoints is lost
Solution Approach 1:
The patent makes any MIP on the circular path capable of initiating connectivity checks, providing universality in the check initiation process. This maintains simplicity while enabling verification of circular protection paths without predefined source or destination nodes.
Data Source
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AI summary
It is disclosed a method for checking connectivity of a bidirectional circular path provided in a communication network comprising a number of nodes connected according to a ring topology. The bidirectional circular path comprises two counter-rotating unidirectional circular paths. The nodes are provided with topology information relating to the communication network. One of the nodes generates a connectivity check packet comprising a TTL field, sets its value based on the topology information, transmits the connectivity check packet along one of the two counter-rotating paths and receives it at the opposite side from the same path. In response to the connectivity check packet, the node generates a connectivity check response packet comprising a TTL field, sets its value based on the topology information and transmits the connectivity check response packet along the other counter-rotating path.