Optical Access Node Internal OAM Domain for Ethernet Fault Diagnosis
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Solution Overview
Problem
Current methods in Passive Optical Networks (PON) systems lack an effective mechanism for actively diagnosing and locating Ethernet-level faults between the Optical Line Terminal (OLT) and Optical Network Unit (ONU) within the access node, limiting operators' ability to diagnose and maintain Ethernet connectivity.
Innovation Solution
Establishing at least two Maintenance End Points (MEPs) within the optical access node to form an internal Operation, Administration, and Maintenance (OAM) domain, allowing for the transmission of Ethernet OAM messages between these points, which includes a Virtual Local Area Network (VLAN) identifier, enabling active fault diagnosis and connectivity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing EPON standard (IEEE 802.3ah) is used for physical layer fault diagnosis, then simple loop-back and bit error rate detection methods are available, but no specific maintenance and administration method exists at the Ethernet level
Solution Approach 1:
The patent segments the OAM functionality by establishing separate MEPs at different locations (OLT network side interface and ONU user side interface) within the access node. This segmentation allows independent fault diagnosis at the Ethernet level without complicating the overall system architecture, resolving the contradiction between reliability improvement and complexity avoidance
2Ease of operation
If the OLT is configured to passively respond to fault detection, then the system maintains simplicity, but the OLT cannot actively diagnose and locate faults at the Ethernet level
Solution Approach 1:
The patent implements preliminary action by pre-configuring multiple MEPs and an internal OAM domain within the access node before faults occur. This allows the OLT to actively initiate fault diagnosis at the Ethernet level without adding operational complexity during actual fault management, as the diagnostic framework is already in place
3Adaptability or versatility
If conventional Ethernet OAM frame formats are used, then compatibility is maintained, but they are unitary and unfit for the TR101 Virtual Local Area Network service model
Solution Approach 1:
The patent applies local quality by modifying the Ethernet OAM frame format to include VLAN-specific fields (VLAN ID, VLAN priority) at specific locations within the message structure. This allows the OAM messages to be adapted for TR101 VLAN service models while maintaining the overall Ethernet OAM framework, achieving adaptability without excessive complexity
Data Source
Figure 1~2
AI summary
A method for administrating optical access nodes is disclosed. The method comprises: more than one administration terminal node is established among the optical access nodes, and the internal operation, administration and maintenance (OAM) domain containing said administration terminal nodes is constructed; the Ethernet OAM message is transmitted between the administration terminal nodes, and according to the virtual local area network (VLAN) property of the user, said OAM message carries the VLAN tag which corresponds to the VLAN property of the user. The present invention also provides an optical access node. The present invention provides a fault diagnosis mechanism in Ethernet layer between optical line terminals (OLT) and optical network units (ONU) inside the optical access node, and the limitation that conventional Ethernet OAM frame format is unitary and unfit for TR101 VLAN service model can be broken through. The service operation is not affected during the usage of the present invention, and the Ethernet maintenance requirements of optical access nodes under the TR101 VLAN construction are resolved for the operator.