Passive Optical Network Error Handling via Protocol Layer Feedback
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Solution Overview
Problem
Current communication protocols in passive optical networks silently discard data with unrecoverable errors, leading to reduced system throughput, increased latency, and loss of synchronization, which is detrimental for both real-time and non-real-time applications.
Innovation Solution
Implementing a mechanism where a lower protocol layer signals error events to a higher protocol layer, allowing the higher layer to parse and recover portions of data unaffected by errors, and optionally accept control messages with invalid check codes under specific criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data with uncorrectable errors is silently discarded by lower protocol layers, then data integrity is maintained, but system throughput is reduced and latency increases due to retransmission requirements at higher layers
Solution Approach 1:
The patent implements a feedback mechanism where the lower protocol layer (physical layer) signals error events to the higher protocol layer (transmission convergence layer). This is achieved through an error indication field in the GTC frame header that provides real-time feedback about error conditions, enabling the higher layer to make informed decisions about data handling without requiring silent discarding or full retransmission
Solution Approach 2:
The patent enables selective recovery of data by allowing the higher protocol layer to parse and extract usable portions of data frames that contain errors. Instead of discarding entire frames with errors, the system can recover valid data segments while isolating the erroneous portions, thereby maintaining throughput while preserving data integrity
2Reliability
If retransmission protocols are implemented at higher protocol layers, then data correctness is improved, but latency increases due to timer expiration waits
Solution Approach 1:
The patent implements preliminary error detection and indication at the physical layer before data is passed to higher layers. By detecting errors early and providing immediate indication through the error field in frame headers, the system prevents the need for higher layers to implement time-consuming retransmission protocols, thereby reducing latency while maintaining correctness
3Reliability
If data packets are silently discarded by lower protocol layers, then error propagation is prevented, but synchronization is lost in structured data streams
Solution Approach 1:
The error indication field provides continuous feedback to the higher protocol layer about the status of received data frames. This feedback mechanism allows the higher layer to maintain synchronization by detecting error patterns and adjusting its parsing and processing accordingly, preventing synchronization loss while containing errors through informed decision-making
Solution Approach 2:
The transmission convergence layer acts as an intermediary between the physical layer and network layer. It receives error indications from the physical layer and uses this information to mediate data processing, enabling synchronization maintenance through intelligent parsing and error handling without requiring silent discarding that would disrupt synchronization
4Reliability
If the entire data stream is discarded when an error is detected, then data integrity is preserved, but system throughput is reduced by unnecessary retransmissions
Solution Approach 1:
The patent implements selective discarding and recovery by enabling the higher protocol layer to parse data frames and identify which portions are affected by errors. Valid data segments can be extracted and processed while only the erroneous portions are discarded, thereby preserving data integrity for usable data while maintaining high throughput by avoiding unnecessary discarding of error-free data
Solution Approach 2:
The patent applies local quality control by allowing different portions of the data stream to be treated differently based on their error status. Error-free segments are processed normally while erroneous segments are identified and handled separately, enabling localized error containment without affecting the overall throughput of the system
Data Source
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AI summary
When data containing an unrecoverable error is received, instead of discarding the data, a lower protocol layer delivers the data to a higher protocol layer along with an indication that the data contains an error. The higher protocol layer parses the data to recover portions that are not affected by the error. Additionally, the higher protocol layer can choose to accept the data if certain acceptance criteria are met.