Ethernet Tree Connectivity Fault Management via Segmented Maintenance Associations
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Solution Overview
Problem
In Ethernet Tree (E-Tree) type service instances, the current IEEE 802.1ag standard causes erroneous defect indications in leaf MEPs due to their inability to receive Connectivity Check Messages (CCMs) from each other, leading to false fault detection even when their operation is normal.
Innovation Solution
The solution involves modifying the definition of Maintenance Associations (MAs) to create multiple MAs within a single service instance, where each MA includes only the root MEP and a specific leaf MEP, and introducing a new configuration parameter to manage active remote MEP state machines, ensuring that only necessary MEPs exchange CCMs and that inactive remote MEP state machines do not generate defect indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current IEEE 802.1ag standard is applied to E-Tree service instances, then fault detection capability is provided, but erroneous defect indications occur in leaf MEPs due to inability to receive CCMs from each other
Solution Approach 1:
The patent segments the single Maintenance Association into multiple MAs, where each MA contains only the root MEP and one leaf MEP. This segmentation allows each leaf MEP to have a dedicated communication path for CCM exchange with the root, eliminating the erroneous defect indications that occur when all leaf MEPs are forced into a single MA where they cannot receive each other's CCMs.
2Measurement precision
If multiple MAs are created in a single service instance, then erroneous defect indications are avoided, but fundamental changes to the definition of MA and IEEE 802.1ag architecture are required
Solution Approach 1:
The patent introduces a dynamic configuration parameter that allows the system to adapt the MA structure based on the service instance type. For E-Tree services, the system dynamically creates multiple MAs with specific leaf MEPs assigned to each, while maintaining the standard single-MA structure for other service types. This dynamic approach resolves the contradiction by allowing architectural flexibility without mandating complex changes across all Ethernet services.
3Ease of operation
If a single MA is used for all MEPs in an E-Tree service, then configuration simplicity is maintained, but leaf MEPs cannot receive CCMs from each other leading to false fault detection
Solution Approach 1:
The patent segments the single MA into multiple smaller MAs, each containing the root MEP and one leaf MEP. This segmentation resolves the fundamental incompatibility between using a single MA for all MEPs and the E-Tree topology where leaf nodes cannot directly communicate. The segmentation maintains configuration simplicity by providing a clear, systematic approach to creating multiple MAs based on service instance parameters.
Data Source
AI summary
A Maintenance Association and corresponding method for configuring maintenance entities for Ethernet Tree (E-Tree) type service instances. A root MEP communicates with each of a plurality of leaf MEPs. Remote MEP state machine instances are activated within the root MEP for each of the plurality of leaf MEPs. Within each leaf MEP, however, only the remote MEP state machine instance for the root MEP is activated while leaving the remote MEP state machine instances for all other leaf MEPs in an inactive state in which Connectivity Check Messages (CCMs) are not exchanged.