10G EPON Reporting Mechanism for Upstream Bandwidth Waste
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Solution Overview
Problem
The existing ONU-OLT report-grant mechanism in 10G EPON results in wasted upstream bandwidth due to the rounding up of report values to the nearest time quantum (TQ) units, leading to excessive allocation of FEC codewords, which could have been assigned to other ONUs.
Innovation Solution
Implementing a method that allows for the rounding down of queue occupancy reports to the nearest TQ units when feasible, thereby reducing the number of FEC codewords allocated, and adjusting report values to optimize bandwidth utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ONU rounds up the report value to TQ units to ensure sufficient bandwidth allocation, then the QoS requirement is met, but excessive bandwidth is allocated and wasted
Solution Approach 1:
The patent changes the rounding parameter from always rounding up to conditionally rounding up or down based on the relationship between queue occupancy and FEC codeword boundaries. When queue occupancy is close to the next FEC boundary, the system rounds down to avoid allocating an entire extra FEC codeword that would be mostly wasted. This parameter change resolves the contradiction by adapting the rounding behavior to the specific data state.
Solution Approach 2:
The patent introduces dynamic decision-making in the rounding process. Instead of a static always-round-up rule, the system dynamically evaluates whether to round up or down based on real-time queue occupancy levels and FEC codeword boundaries. This dynamic approach allows the system to optimize bandwidth allocation in each reporting cycle, reducing waste while maintaining QoS.
2Productivity
If the OLT allocates bandwidth based on rounded-up report values, then all ONUs receive sufficient bandwidth, but the aggregate upstream bandwidth utilization efficiency decreases
Solution Approach 1:
The patent modifies the bandwidth allocation parameter by introducing conditional rounding logic. The system calculates both the rounded-up and rounded-down report values, then compares them against FEC codeword boundaries to determine the optimal rounding direction. This parameter optimization reduces excess bandwidth allocation while ensuring each ONU receives sufficient resources for its actual traffic needs.
Solution Approach 2:
The patent replaces the mechanical always-round-up mechanism with a smarter computational approach that considers FEC codeword boundaries. Instead of blindly rounding up, the system substitutes a calculation-based decision process that evaluates whether the fractional part of the report value justifies allocating an entire additional FEC codeword, thereby improving overall system efficiency.
3Measurement precision
If the report granularity is increased to reduce rounding errors, then bandwidth allocation precision improves, but the complexity of the report-grant mechanism increases
Solution Approach 1:
The patent segments the rounding decision into distinct cases: when to round up and when to round down. By dividing the decision space based on queue occupancy thresholds and FEC boundary relationships, the system achieves precise bandwidth allocation without requiring complex continuous calculations. This segmentation maintains simplicity while improving accuracy.
Solution Approach 2:
Instead of increasing report granularity to improve precision, the patent inverts the approach by optimizing the rounding behavior at the existing granularity level. Rather than reporting more detailed information, the system intelligently rounds to the appropriate precision level, achieving accurate bandwidth allocation without increasing report complexity or processing overhead.
Data Source
AI summary
Methods for increasing upstream bandwidth utilization in an Ethernet passive optical network (EPON) use in some instances round-down instead of round-up occupancy values reported to an optical line terminal. An optical network unit determines whether the occupancy needs to be round-up or round-down and reports the occupancy in either round-up or round-down report units to the optical network terminal.