Ethernet Clock Determination for Upstream Clock Continuity
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Solution Overview
Problem
Edge devices in optical transport networks cannot continue transmitting the clock of an upstream device through non-flexible Ethernet interfaces due to reliance on local crystal oscillators, limiting the precision of the sending clock.
Innovation Solution
A method and apparatus that enable network devices to determine a clock based on signals received from upstream devices, using physical layer clocks derived from these signals to serve as the sending clock for non-flexible Ethernet interfaces, thereby allowing the transmission of upstream clocks through these interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a local crystal oscillator is used to generate the sending clock for the non-flexible Ethernet interface, then the edge device can independently send data, but the clock continuity and precision are limited
Solution Approach 1:
The patent introduces an intermediary mechanism (clock selection and determination module) that selects between the local crystal oscillator clock and the upstream device's clock based on signal availability. When the upstream clock signal is available, it is used as the sending clock for the non-flexible Ethernet interface, ensuring clock continuity. This intermediary selection resolves the contradiction by dynamically switching between local and upstream clocks.
Solution Approach 2:
The patent implements dynamic clock source selection where the edge device can switch between using its local crystal oscillator and using the upstream device's clock signal. This dynamic adaptation allows the system to optimize clock precision when upstream signals are available while maintaining independence when they are not, resolving the static limitation of conventional crystal oscillator-based systems.
2Adaptability or versatility
If the edge device uses its local crystal oscillator as the sending clock, then it can operate independently, but it cannot continue transmitting the upstream device's clock
Solution Approach 1:
The patent makes the clock generation system universal by enabling it to function in multiple modes: it can use the local crystal oscillator for independent operation and can also use the upstream device's clock signal for continuous clock transmission. The clock determination module selectively activates the appropriate function based on system requirements, achieving multi-functionality that resolves the contradiction between adaptability and reliability.
Solution Approach 2:
The patent ensures continuous useful action by maintaining the ability to transmit the upstream device's clock continuously through the non-flexible Ethernet interface when the upstream signal is available. This continuous transmission capability complements the independent operation mode, ensuring that clock synchronization is maintained throughout the network without interruption.
3Device complexity
If the edge device relies solely on the local crystal oscillator, then the system structure is simple, but the clock precision and network synchronization are limited
Solution Approach 1:
The patent implements self-service by enabling the edge device to automatically determine and select the appropriate clock source without external intervention. The clock determination module autonomously evaluates the availability and quality of clock signals and selects the most suitable source, maintaining system simplicity while improving precision through intelligent self-management.
Data Source
AI summary
A method and an apparatus are provided for determining a network device receiving a first signal and at least one second signal, wherein the first signal carries data to be sent through a first flexible Ethernet interface. A first physical layer clock is determined based on the first signal. A second physical layer clock is determined based on the at least one second signal or the first physical layer clock and the at least one second signal. The first physical layer clock or the second physical layer clock is used as a sending clock of a non-flexible Ethernet interface. The network device includes the first flexible Ethernet interface and the non-flexible Ethernet interface.