Hardware CRC Recalculation for Single-Cycle Timestamped Frames
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Solution Overview
Problem
Existing Ethernet port designs face challenges in recalculating cyclic redundancy checks (CRC) for timestamped frames within a single clock cycle, particularly when frames start and end in the same clock cycle, leading to performance degradation and increased logic complexity due to the need for additional clock cycles and complex combinatorial paths.
Innovation Solution
A hardware-based CRC re-calculator is implemented, which modifies the data frame by setting the last bytes to zero, calculates a CRC correction field, and determines a corrected CRC using exclusive OR operations, allowing for CRC recalculation in a single clock cycle without affecting performance and minimizing additional logic footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CRC recalculation is performed for timestamped frames using traditional methods, then CRC accuracy is maintained, but processing time exceeds single clock cycle and logic complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the CRC correction field based on the timestamp value before the actual CRC recalculation. The correction field is computed in advance using the timestamp data, allowing the final CRC to be obtained by simply XORing the original CRC with this pre-computed correction field, thereby enabling single-clock-cycle completion
Solution Approach 2:
The patent segments the CRC recalculation process into two independent parts: (1) calculating CRC of the frame with zeroed last bytes, and (2) calculating the correction field from timestamp bytes. This segmentation allows both operations to be performed in parallel, resolving the time complexity issue while maintaining CRC accuracy
2Measurement precision
If CRC recalculation is performed for timestamped frames using traditional methods, then CRC accuracy is maintained, but device complexity and logic footprint increase
Solution Approach 1:
By pre-computing the correction field from the timestamp, the patent eliminates the need for complex sequential CRC recalculation logic. The correction field calculation is performed once and stored, simplifying the overall device logic while ensuring accurate CRC recalculation through simple XOR operation
Solution Approach 2:
The patent creates a simplified copy of the CRC calculation process specifically for the timestamp portion. Instead of re-calculating the entire CRC, it computes a correction field copy that represents only the timestamp contribution, which can then be combined with the original CRC through XOR, significantly reducing logic complexity
3Speed
If Ethernet port operates at higher speeds up to 800 Gbps, then data processing capability is improved, but verification performance and packet processing speed degrade
Solution Approach 1:
The patent enables high-speed operation by pre-calculating the CRC correction field, allowing verification to complete in a single clock cycle. This eliminates the bottleneck in the verification process, maintaining productivity even as data processing speeds increase to 800 Gbps
Solution Approach 2:
The patent introduces a dynamic correction field calculation mechanism that adapts to different timestamp values. The correction field is dynamically computed based on the actual timestamp data, enabling the verification system to keep pace with high-speed data processing while maintaining accuracy
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
The solution enables correct CRC recalculation for timestamped frames in a single clock cycle, maintaining emulator performance and reducing design complexity, while ensuring minimal area usage and high-speed data processing capabilities up to 800 Gbps.
Implementation Method 1
determining a corrected CRC for the data frame based on at least the CRC of the modified data frame and the CRC correction field
Data Source
AI summary
A method and a system for correcting cyclic redundancy check (CRC) for a frame with last bytes changed are provided. The method includes acquiring a data frame, calculating a CRC of a modified data frame, and determining a corrected CRC for the data frame based on at least the CRC of the modified data frame and a CRC correction field calculated on the bytes to be replaced at the end of the frame. An altered data frame includes the data frame with a number of last bytes of the data frame replaced with new bytes.