SyncE Dual-Master Clock Switching Without Auto-Negotiation
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Solution Overview
Problem
In Synchronous Ethernet (SyncE) networks, the existing master/slave concept only allows timing to be passed in one direction between nodes, requiring re-performation of the auto-negotiation process for directional switching, which can cause delays and link drops, especially in delay-sensitive telecom networks.
Innovation Solution
A dual-master mode architecture that enables Ethernet nodes to dynamically switch between master and slave designations without re-performing the auto-negotiation process, allowing bi-directional timing delivery by using a transmit clock generation module that selects between an extracted clock and a primary reference source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the master/slave concept is used in SyncE to pass timing from node to node, then timing synchronization is achieved, but the timing direction cannot be dynamically switched without re-performing the auto-negotiation process
Solution Approach 1:
The patent implements dynamic role switching between master and slave nodes without requiring re-negotiation. The system allows nodes to dynamically change their timing delivery direction by switching between master and slave designations in real-time, making the previously static master/slave relationship dynamic and adaptable to changing network conditions.
Solution Approach 2:
The patent changes the operational parameters of the SyncE system by allowing the timing delivery direction parameter to be dynamically modified. Nodes can switch their role designation and timing delivery direction by changing operational parameters such as clock source selection and timing delivery enablement, without triggering the auto-negotiation process.
2Adaptability or versatility
If the auto-negotiation process is re-performed for directional switching, then the timing direction can be changed, but link drops and significant delays occur
Solution Approach 1:
The system performs preliminary configuration during the initial auto-negotiation process, establishing both master and slave designations and preparing clock source selection mechanisms. This preliminary setup enables subsequent directional switches to be performed rapidly by simply activating pre-configured parameters rather than re-negotiating the entire connection.
Solution Approach 2:
The patent introduces dynamic role assignment where nodes can switch between master and slave designations on-demand. The system dynamically adjusts timing delivery direction by changing node roles and enabling/disabling timing delivery based on current network conditions, providing flexibility without disrupting the link.
3Ease of operation
If a node uses a free-running crystal oscillator as master, then timing can be generated locally, but clock signal deterioration can occur without backup options
Solution Approach 1:
The patent prepares backup clock sources in advance, including both master and slave designations with alternative clock sources. When a node is designated as master, the system has pre-configured backup options ready to be activated if the primary clock source deteriorates, providing redundancy before failures occur.
Solution Approach 2:
The system dynamically changes clock source parameters based on signal quality. Nodes can switch between different clock sources (local crystal oscillator, recovered clock, external reference) by changing operational parameters, allowing the system to adapt to clock signal deterioration and maintain stability through parameter adjustment rather than link re-establishment.
Data Source
AI summary
Embodiments of a dual-master mode Ethernet node are provided herein. The dual-master mode Ethernet node includes a first multiplexer configured to select between a local oscillator signal and a primary reference source (PRS) signal to provide a reference clock signal, a digital phase-locked loop (DPLL) configured to generate a master clock signal based on the reference clock signal, a phase rotator configured to rotate a phase of the master clock signal based on a frequency error between the master clock signal and an extracted clock signal to generate a slave clock signal, and a second multiplexer configured to select between the master clock signal and the slave clock signal to provide a transmit clock signal. The dual-master mode Ethernet node can dynamically generate the transmit clock based on either the extracted clock or the PRS without re-performing the auto-negotiation process.