Root Clock Synchronization via Dedicated Links
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Solution Overview
Problem
Existing clock synchronization methods in network communications, such as Synchronous Ethernet (SyncE), face challenges in scaling to larger networks due to added noise and latency with each hop, limiting their ability to synchronize multiple devices accurately.
Innovation Solution
A synchronized communication system where a root device generates a precise root clock signal, which is distributed over dedicated clock links to slave devices, allowing multiple devices to share the same synchronized clock without relying on the data network for clock distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clock signals are distributed over the data network (SyncE method), then network devices can be synchronized, but noise and latency increase with each hop, limiting scalability
Solution Approach 1:
The system separates clock signal distribution from data transmission by implementing dedicated clock links independent of the data network. This segmentation allows clock signals to be distributed through a separate physical infrastructure, avoiding the noise and latency issues that accumulate when clocks are distributed over data network hops.
Solution Approach 2:
A root device acts as an intermediary that generates a master clock signal and distributes it to slave devices through dedicated clock links. This intermediary approach centralizes clock generation and distribution, eliminating the need for each device to synchronize through multiple hops in the data network, thereby reducing accumulated noise and latency.
2Reliability
If multiple devices share the same clock through data network hops, then synchronization is achieved, but latency and noise accumulate with each hop
Solution Approach 1:
The system divides the network into slave devices and a root device, with dedicated clock links providing direct clock signal paths from the root device to each slave device. This segmentation eliminates multi-hop clock distribution, reducing the accumulation of latency and noise that occurs when clocks are propagated through multiple data network intermediaries.
3Reliability
If dedicated clock links are used for each slave device, then synchronization accuracy is maintained, but system complexity increases
Solution Approach 1:
The root device serves multiple functions: it generates the master clock signal, manages the distribution to multiple slave devices, and maintains synchronization across the entire network. This universal approach consolidates clock management functionality in a single device, reducing overall system complexity despite the use of dedicated clock links.
Solution Approach 2:
Each slave device independently receives and locks onto the clock signal from the root device through its dedicated clock link, without requiring complex coordination with other slave devices. This self-service approach simplifies the system architecture by eliminating the need for inter-slave-device clock coordination protocols.
Data Source
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AI summary
A synchronized communication system includes a plurality of network communication devices, one of which is designated as a root device and the others designated as slave devices. Each network communication device includes one or more ports and communications circuitry, which processes the communication signals received by the one or more ports so as to recover a respective remote clock from each of the signals. A synchronization circuit is integrated in the root device and provides a root clock signal, which is conveyed by clock links to the slave devices. A host processor selects one of the ports of one of the network communication devices to serve as a master port, finds a clock differential between the root clock signal and the respective remote clock recovered from the master port, and outputs, responsively to the clock differential, a control signal causing the synchronization circuit to adjust the root clock signal.