Layer 2 Data Path Integrity Validation via Coordinated OAM Messaging
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Solution Overview
Problem
Conventional methods for data path integrity validation at Layer 2 are hindered by the inability to verify end-to-end integrity when intermediate Layer 2 switches are present, as test signals are terminated at each interface, and require the service to be run out of service, making it mutually exclusive with service traffic.
Innovation Solution
A method and apparatus for end-to-end data path integrity validation at Layer 1 and Layer 2 that involves messaging between network elements to coordinate defect and statistics collection, using an encapsulation protocol like VLAN to ensure control frames follow the same path as service traffic, allowing for in-service testing with a consolidated report provided to a management system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Layer 2 test signals are used, then physical path characteristics can be monitored, but end-to-end data path integrity cannot be verified when intermediate Layer 2 switches are present
Solution Approach 1:
The patent segments the end-to-end test into multiple coordinated segments by deploying test agents at intermediate Layer 2 switches. Each agent independently tests its local segment and reports results to the OAM system, which consolidates them into a complete end-to-end verification. This resolves the contradiction by maintaining measurement precision across the entire path while accommodating the presence of intermediate switches that would otherwise break the test signal.
Solution Approach 2:
The patent introduces an OAM (Operations, Administration, and Maintenance) system as an intermediary that coordinates testing across multiple network elements. The OAM system manages test signal generation, collects results from intermediate switches, and performs end-to-end verification. This mediator enables integrity verification across the complete path while working around the signal termination issue caused by intermediate Layer 2 switches.
2Reliability
If test signals are sent through the data path, then integrity validation can be performed, but service traffic must be stopped (out of service testing)
Solution Approach 1:
The patent implements multi-functionality by enabling the data path to simultaneously carry both service traffic and test signals through technique such as VLAN tagging or dedicated OAM VLANs. The test agents and OAM system are designed to handle both production traffic and test functions concurrently, allowing integrity validation without stopping service traffic. This resolves the contradiction by making the system capable of performing both functions at once.
Solution Approach 2:
The patent ensures continuous service operation during testing by implementing in-service test capabilities. Test signals are injected and monitored without interrupting the normal data flow, and the OAM system coordinates testing to minimize impact on production traffic. This maintains the continuity of useful action (service traffic) while performing integrity validation.
3Measurement precision
If test signals flow through intermediate switches, then complete path testing is possible, but test signals are terminated at each Layer 2 interface
Solution Approach 1:
The OAM system acts as a mediator that orchestrates testing across multiple network elements. Instead of relying on a single test signal to traverse the entire path (which fails at Layer 2 interfaces), the OAM system coordinates multiple localized tests at each switch and consolidates the results. This approach achieves end-to-end verification while working within the operational constraints of Layer 2 switch interfaces.
Solution Approach 2:
The testing approach is segmented into multiple independent tests performed at each network element, with results aggregated by the OAM system. Each segment test is operationally simple and doesn't require complex signal propagation through intermediate switches, while the collective results provide end-to-end verification. This segmentation resolves the contradiction between verification completeness and operational simplicity.
Data Source
AI summary
Systems and methods of end-to-end data path integrity validation of a service with a data path at Layer 1 and Layer 2 implemented by a network element include, responsive to initiation of a test, messaging between network elements in the data path to coordinate defect and statistics collection at each of the network elements in the data path; receiving results for the defect and statistics collection from each of the network elements in the data path; and summarizing the received results to form a consolidated report for the test across all of the network elements in the data path.