Auto-Negotiation Re-timer for Shared PLL Network Transceivers
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Solution Overview
Problem
In network systems, devices connected to a shared PLL port often operate at the lowest common denominator (LCD) capability, limiting data transfer rates and preventing individual lanes from reaching their maximum potential, and re-timers do not support auto-negotiation, leading to mismatched communication capabilities between devices.
Innovation Solution
The use of rate-adapting transceivers that facilitate auto-negotiation to establish the highest common denominator (HCD) capability for each lane and a re-timer that participates in auto-negotiation to allow independent capability usage between devices, enabling each link to utilize different features like FEC as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If devices connected to a shared PLL port operate at the lowest common denominator capability, then compatibility between devices is ensured, but data transfer rates are limited and individual lanes cannot reach maximum potential
Solution Approach 1:
The patent divides the shared PLL port into independent lanes, each capable of negotiating its own capability level. This segmentation allows different lanes to operate at different data rates (e.g., some at 25 Gbps, others at 10 Gbps) without compromising overall system compatibility, resolving the contradiction between ensuring compatibility and maximizing data transfer rates.
Solution Approach 2:
The patent implements dynamic capability negotiation where each lane can independently determine its operating mode based on the connected devices' capabilities. This dynamic adjustment allows the system to adapt from a static LCD approach to a flexible HCD model, enabling optimal performance while maintaining compatibility across heterogeneous devices.
2Device complexity
If re-timers do not support auto-negotiation, then device complexity is reduced, but communication capability mismatches occur between devices
Solution Approach 1:
The patent introduces the re-timer as an intermediary device that actively participates in auto-negotiation between network devices. This mediator exchanges capability information with connected devices, determines appropriate communication modes, and configures its own operation accordingly. This resolves the contradiction by enabling the re-timer to support auto-negotiation (improving compatibility) while maintaining manageable complexity through a standardized negotiation process.
3Device complexity
If all lanes must operate at the same capability level due to shared PLL, then system simplicity is maintained, but individual lane performance is limited
Solution Approach 1:
The patent segments the shared PLL architecture into independent lane-level control mechanisms. Each lane maintains its own capability negotiation and operation mode, allowing differential performance (e.g., 25 Gbps for some lanes, 10 Gbps for others) while preserving the simplicity of the shared PLL structure. This segmentation enables high-performance lanes to operate at maximum speed without forcing the entire system to operate at the lowest common denominator.
Data Source
AI summary
A rework re-timer with forward error correction handling is disclosed. An example first intermediate transceiver includes a first interface to communicatively couple the first intermediate transceiver with a first computing device, a second interface to communicatively couple the first intermediate transceiver to a second intermediate transceiver configured to be communicatively coupled with a second computing device, an auto-negotiation controller to: terminate a first auto-negotiation with the first computing device before the first auto-negotiation is completed, transmit, to the second transceiver, first capabilities of the first computing device determined during the first auto-negotiation, and perform a second auto-negotiation with the first computing device utilizing the first capabilities of the first computing device and second capabilities of the second computing device received from the second transceiver.