Multi-Lane Link Low-Latency Control Word Transmission
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Solution Overview
Problem
Current multi-lane point-to-point communication protocols require lane-to-lane deskew at the receiver, which can be disadvantageous for applications needing low-latency data transmission, such as control information like XON/XOFF and ACK/NACK messages, as it increases buffering requirements and latency.
Innovation Solution
Designating a single lane for transmitting low-latency word categories across the link, allowing for early reading of control words before lane-to-lane deskew is completed, while other words are striped across available lanes, minimizing overall latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lane-to-lane deskew is performed at the receiver for all transmitted words, then data integrity across multiple lanes is maintained, but latency increases and buffering requirements increase
Solution Approach 1:
The patent segments transmitted words into two categories: low-latency control words and normal data words. Control words are transmitted on a dedicated lane without requiring deskew operations, while normal words use all lanes with deskew. This segmentation allows critical control information to bypass the latency-inducing deskew process while maintaining data integrity for regular data transmission.
Solution Approach 2:
The patent applies different quality requirements to different types of data. Control words receive preferential treatment with a dedicated lane and exemption from deskew operations, while normal data words undergo standard multi-lane deskew processing. This local quality differentiation optimizes the system for both speed (control words) and reliability (normal data).
2Stability of the object's composition
If lane-to-lane deskew is performed at the receiver, then data alignment across lanes is achieved, but buffering requirements increase
Solution Approach 1:
The patent divides the data stream into control words and normal words, routing control words through a dedicated lane that does not require buffering for deskew alignment. This eliminates the need for large buffers while maintaining proper alignment for normal data transmission that does use multiple lanes.
3Productivity
If all words are transmitted across all available lanes, then bandwidth utilization is maximized, but control information latency increases
Solution Approach 1:
The patent segments the transmission medium into a dedicated control lane and data lanes. Control words exclusively use the dedicated lane, ensuring minimal latency, while normal data words utilize all lanes for maximum bandwidth utilization. This segmentation resolves the contradiction between speed and throughput.
Solution Approach 2:
The patent extracts control words from the general data stream and transmits them through a separate dedicated lane. This extraction allows control information to bypass the congested multi-lane data transmission path, reducing latency while normal data continues to fill all available lanes for maximum bandwidth utilization.
Data Source
AI summary
One embodiment relates to an integrated circuit configured to communicate a low-latency word category over a multi-lane link. A transmitter controller is configured to transmit words belonging to the low-latency word category only over a designated lane of the multi-lane link and to transmit words belonging to non-low-latency word categories over any available lane of the multi-lane link. A receiver controller may be configured to determine a word category of a word received over the designated lane and, if the word category is determined to be the low-latency word category, then read the word from the designated lane before lane-to-lane deskew is completed. Other embodiments, aspects, and features of the invention are also disclosed.