Physical Layer Aggregation Overhead Reduction
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Solution Overview
Problem
The existing Aggregation at the Physical Layer (APL) approach is not a line rate solution due to the addition of idle characters and fragment overhead, leading to inefficiencies and increased complexity in processing high-rate data, particularly when distributing packets to multiple 10 Gbit PHYs.
Innovation Solution
The proposed solution involves distributing packet data into large frames that are passed to each Physical Coding Sublayer (PCS), minimizing overhead and maintaining line rate by using a blocking/framing process that discards idle characters and inserts fill control characters as needed to compensate for data gaps, allowing for efficient transmission without reordering fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing APL approach is used to aggregate multiple PHYs, then link aggregation functionality is achieved, but overhead increases due to idle characters and fragment overhead, reducing transmission efficiency
Solution Approach 1:
The patent extracts and removes the problematic idle characters and fragment overhead from the transmission stream. The physical layer aggregation function identifies and eliminates these unnecessary elements that were being added by the existing APL approach, thereby recovering transmission efficiency while preserving link aggregation functionality.
Solution Approach 2:
The patent discards the redundant idle characters and fragment overhead that were being inserted, and recovers the lost transmission efficiency. By eliminating these unnecessary elements and optimizing the aggregation process, the system achieves both link aggregation capability and improved transmission efficiency.
2Adaptability or versatility
If the existing APL approach is used to aggregate multiple PHYs, then link aggregation is achieved, but processing complexity increases due to fragment overhead and idle character management
Solution Approach 1:
The patent extracts and removes the complex fragment overhead and idle character management mechanisms from the processing pipeline. By eliminating these unnecessary processing steps, the system maintains link aggregation capability while significantly reducing processing complexity.
Solution Approach 2:
The patent discards the complex fragment overhead structures and idle character management procedures, and recovers the simplified processing architecture. This approach maintains the essential link aggregation function while eliminating the sources of processing complexity.
3Productivity
If packet data is distributed to multiple PHYs using traditional APL, then load distribution is achieved, but line rate transmission is not maintained due to overhead additions
Solution Approach 1:
The patent extracts and removes the overhead elements (idle characters and fragment overhead) that were preventing line rate transmission. By eliminating these additions, the system achieves both effective load distribution across multiple PHYs and maintenance of line rate transmission speeds.
Solution Approach 2:
The patent changes the transmission parameters by removing the overhead additions and optimizing the data distribution mechanism. This allows the system to maintain line rate transmission while still achieving effective load distribution across the aggregated PHYs.
Data Source
AI summary
A physical layer device distributes a high-speed packet data stream to multiple lower-speed physical channels, and reverses the process to receive a high-speed packet data stream that has been distributed across multiple lower-speed physical channels. The packet data is distributed by removing interpacket gap characters from between packets and using a different control character to delineate packets. Interpacket gap characters can then be used to delineate equal-length frames distributed to each of the multiple physical channels. Each frame consists of a concatenation of fixed-size blocks of packet data. By selecting a frame size larger than the average packet size, overhead on the multiple physical channels can actually be lower than the overhead on the single high-speed channel, allowing the aggregation to achieve line rate operation at the high-speed rate.