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Clock synchronization method, network device and network system

A technology for clock synchronization and network equipment, applied in time division multiplexing systems, electrical components, multiplexing communications, etc., can solve problems such as clock synchronization cannot be achieved, phase drift cannot be eliminated, and sink node equipment recovers clocks, etc.

Inactive Publication Date: 2018-12-14
BEIJING HUAWEI DIGITAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, during the PHY synchronization process, once the PHY layer business is interrupted, the sink node device cannot recover the clock from the PHY layer during the intermittent period, and the phase following the source node device will drift. When the PHY layer business resumes, Frequency can be resynchronized, but phase drift cannot be eliminated, making clock synchronization impossible

Method used

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  • Clock synchronization method, network device and network system
  • Clock synchronization method, network device and network system
  • Clock synchronization method, network device and network system

Examples

Experimental program
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Effect test

Embodiment 1

[0049] Take the back-to-back scenario in clock tracking as an example, such as figure 1 A schematic diagram of a relationship between a source node device and a sink node device is shown. Source node device A 1 During the process of sending service data, a time stamp T1 is periodically added to the service data output at the egress port of the source node device A1. That is to say, a time stamp T1 is added to the transmitted business data every preset time, and the time stamp T1 is used to mark the source node device A 1 The current moment of the local RTC (Real-Time Clock, real-time clock). When the service data is transmitted to the sink node device A 2 When the service data is transmitted to the sink node device A 2 When the ingress port of the sink node device A 2 Get the timestamp T2 used to mark the current moment of the local RTC.

[0050] based on the above figure 1 In the simplified structure of the network system shown, the source node device sends service dat...

Embodiment 2

[0072] Taking the multi-level cascading scenario in clock tracking as an example, add N intermediate node devices between the source node device and the sink node device, N≥1, N is a positive integer, and the link delay between each node device is stable. For example, each node device is connected with an optical fiber, and has a fixed link delay. Alternatively, the link delay between various node devices is generated by processing services with a fixed delay.

[0073] Such as image 3 A schematic diagram of a relationship between a source node device, an intermediate node device, and a sink node device is shown. Source node device A 1 In the process of sending business data, periodically output source node device A 1 Time stamp T1 is added to the business data at the egress port. That is to say, a time stamp T1 is added to the transmitted business data every preset time, and the time stamp T1 is used to mark the source node device A 1 The current moment of the local RTC...

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Abstract

The invention provides a clock synchronization method, a network device and a network system. After transmission of service data in a PHY (Physical Layer) is recovered, a destination node device recovers own frequency based on the frequency of a source node device obtained from the service data. The destination node device calculates a difference value between a time stamp of receiving the service data and the time stamp which is carried in the service data and is marked by the source node device, wherein the time stamp of receiving the service data is recorded by a local clock. After own frequency is synchronized with the frequency of the source node device, the destination node device adjusts own phase according to the difference value, so own phase is synchronized with that of the source node device, and the clock synchronization between the destination device and the source node device is realized.

Description

technical field [0001] The present invention relates to the technical field of clock synchronization, and more specifically, to a clock synchronization method, network equipment and a network system. Background technique [0002] Clock synchronization refers to the synchronization of frequency and phase. In the current clock synchronization system, there are two most commonly used clock synchronization methods: one is PTP1588 (Precision Time Protocol 1588, a precision clock synchronization protocol standard for network measurement and control systems) Synchronization mode, the other is PHY (physical layer, physical layer) synchronization mode. [0003] In the process of frequency and phase synchronization, the PTP1588 synchronization method needs to occupy additional bandwidth to carry PTP1588-related messages in the link, which has the problem of high landing cost in some business transmission scenarios. Compared with the PTP1588 synchronization method, the PHY synchroniza...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04J3/06
CPCH04J3/0667H04J3/0682H04J3/0685
Inventor 金学淼邓晨吴锋曾建华
Owner BEIJING HUAWEI DIGITAL TECH