OTN Service Clock Transparent Transmission via Two-Level Buffering
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Solution Overview
Problem
Traditional methods for service clock transmission in optical transport networks (OTNs) face limitations, particularly with asynchronous mapping, where transparent transfer of customer service clocks is restricted, leading to challenges in recovering high-quality synchronous clocks.
Innovation Solution
A method and system for service clock transparent transmission in OTNs, involving de-mapping at the OTN receiving end, followed by two-level buffering operations using a first and second buffering unit, where the first unit performs homogenization under OTN clock control and the second unit outputs data according to the service clock, with a phase-locked loop (PLL) adjusting the clock frequency based on data bulk, ensuring stable data distribution and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If asynchronous mapping is adopted to transmit service data flow through OTN, then the service data flow can be encapsulated into OTN payload according to OTN clock, but the service clock information cannot be recovered at the OTN receiving end
Solution Approach 1:
The patent divides the buffering operation into two distinct stages: a first buffering unit for homogenization and a second buffering unit for clock recovery. This segmentation allows each unit to perform its specific function optimally - the first unit handles data rate matching while the second unit recovers the service clock, thereby preventing loss of clock information while maintaining asynchronous mapping adaptability
Solution Approach 2:
The patent introduces an intermediary mechanism (the two-level buffering system with reading enabling signal) between the OTN payload and the service clock recovery process. This intermediary extracts and processes timing information from the asynchronous data flow, enabling clock recovery without requiring synchronous mapping, thus preserving service clock information while maintaining mapping flexibility
2Reliability
If synchronous mapping is adopted to transmit service clock, then the service clock can be used to encapsulate service data flow in OTN, but there must be a fixed frequency ratio between accessing service and OTN service which restricts multi-channel customer service clock transparent transfer
Solution Approach 1:
The patent implements dynamic buffering operations where the reading enabling signal adjusts the reading rate of the first buffering unit based on the service clock frequency ratio. This dynamic adjustment allows the system to adapt to different service clock frequencies without requiring a fixed frequency ratio, enabling multi-channel customer service clock transparent transfer while maintaining reliable clock transmission through controlled buffering and homogenization
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures high-quality recovery of the service synchronous clock, maintaining data stability and minimizing phase-locked loop adjustments, thus meeting customer requirements for service clock quality.
Implementation Method 1
the second buffering unit reads out the service data flow locally according to the service clock provided by a phase locked loop (PLL); the PLL adjusting the service clock according to amount of data bulk in the second buffering unit
Data Source
AI summary
A method and system for service clock transparent transmission in an optical transport network (OTN) are provided. The system includes a service accessing end and an OTN receiving end; the method includes the following steps: the OTN receiving end performs de-mapping operation to an OTN frame after receiving the OTN frame, and performs two-level buffering operation to the service data flow recovered therefrom, a first buffering unit performs a homogenization treatment to the service data flow and then outputs to a second buffering unit, which the second buffering unit outputs the service data flow according to the service clock after receiving the service data flow. After adopting the present invention, it is able to ensure that the quality of the recovered service clock is relatively higher, which meets the customer requirement on the related specification of the service clock.