PON Backbone Link Measurement Before Standby Switching
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Solution Overview
Problem
In passive optical networks (PON), when the active link fails and switches to a standby link, some optical network units (ONUs) may fail to go online due to insufficient optical power, necessitating a reliable method to detect the status of the standby link to ensure seamless service continuity.
Innovation Solution
A link status measurement method where an optical line terminal (OLT) sends indication information to ONUs to measure signal quality within a specified window, using separate channels for measurement and service signals, allowing accurate determination of backbone link status before switching to ensure normal service transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the OLT switches from active link to standby link, then link redundancy is achieved, but optical power may be insufficient causing ONUs to fail to go online
Solution Approach 1:
The patent applies preliminary action by measuring the optical power quality of the standby link before switching from the active link. The OLT sends indication information to ONUs to perform measurements within a specified window, and the OLT obtains the measurement results before initiating link switching. This ensures that the standby link has sufficient optical power quality to support ONUs before the switch occurs, preventing failures during the transition.
2Measurement precision
If link status measurement is performed continuously, then measurement precision is improved, but service disruption increases
Solution Approach 1:
The patent applies periodic action by establishing a measurement window with a specified duration within which ONUs perform link status measurements. The OLT sends indication information containing the measurement window parameters, and measurements are conducted periodically within this window rather than continuously. This approach maintains measurement precision while limiting the time window for measurements, thereby reducing service disruption and improving overall efficiency.
3Reliability
If dual-channel transmission is used for measurement and service signals, then service quality is maintained during measurement, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the transmission channel into two separate channels: a first channel for carrying measurement signals and a second channel for carrying service signals. The OLT and ONUs are configured to send and receive signals on these segmented channels respectively. This segmentation allows measurement operations to be performed independently of service transmission, maintaining service quality during measurements while using a structured channel configuration that manages device complexity through clear functional separation.
Data Source
AI summary
A link status measurement method includes: A first OLT sends first indication information to a first ONU through a first port. The first ONU is one of at least one ONU included in a PON, and the first indication information indicates a measurement window for measuring the first ONU. The first OLT obtains quality of a signal corresponding to the first ONU. The quality of the signal is quality of a signal received by a second port on a second OLT from a first PON channel in a measurement window, and the first PON channel is a channel carried on a link between the second port and the first ONU. The first OLT determines a status of a backbone link based on quality of a signal corresponding to each ONU in the PON. The backbone link is a common part of a link from the second port to each ONU.