WO2009043299A1

WO2009043299A1 - A determining method and device for the synchronization port of a transparent clock equipment

Info

Publication number: WO2009043299A1
Application number: PCT/CN2008/072557
Authority: WO
Inventors: Zhen Luo; Li Luo; Aiguo Yan
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-27
Filing date: 2008-09-26
Publication date: 2009-04-09
Also published as: CN101399655B; CN101399655A

Abstract

The invention belongs to the field of network synchronization techniques, especially to a determining technique for the synchronization port of a transparent clock TC equipment. A determining method and device for the synchronization port of the transparent clock equipment are provided by the embodiments of the present invention, and determining the synchronization port of the TC equipment is performed. The method for determining the synchronization port of the transparent clock equipment includes: obtaining the results of the TC equipment port's monitoring of synchronization indication messages; determining, according to said monitoring results, the port which receives the synchronization indication message as the synchronization port. The determining device for the synchronization port of the TC equipment includes: a first obtaining unit, a calculating unit and a first determining unit. Another kind of determining device for the synchronization port of the TC equipment includes: a second obtaining unit and a second determining unit.

Description

Method and device for determining punching through clock device synchronization port

Technical field

The present invention relates to the field of network synchronization technologies, and in particular, to a method and apparatus for determining a synchronization port of a through-clock device. Background technique

Network Measurement and Control System Accurate Clock Synchronization Protocol IEEE (Institute of Electrical and Electronics Engineers) The basic function of the 1588 is to keep other clocks in the distributed network system synchronized with the most accurate clock. IEEE 1588 defines an accuracy. The Precision Time Protocol (PTP) is used to perform sub-microsecond synchronization of clocks of devices in standard Ethernet or other distributed network systems.

IEEE 1588 divides the clocks in the entire PTP network system into Ordinary Clock (OC) and Boundary Clock (BC) according to the working mode; the main clock and the slave clock are divided according to the communication relationship. A PTP network system can be composed of multiple PTP communication subnets. Each PTP communication subnet has only one master clock, and the best master clock (BMC) automatically selects the master clock in the PTP communication subnet. And the slave clock is synchronized with the master clock. The optimal clock in the PTP network system is the Grandmaster Clock (GMC), which has the best stability, accuracy, certainty, etc. Each network system has only one GMC, only one communication subnet. In the network system, the master clock is the GMC.

A device in OC mode is called an OC device and has only one communication port. A device in BC mode is called a BC device and has more than one communication port. The communication ports of the BC device and the 0C device have port status, and there are three main types, including: main status (Master, M), slave status (Slave, S), and passive status (Passive, P). The communication port with the port status of the master is referred to as the master port. The master port is used to broadcast the best quality clock source to the entire network. The slave port is used to track the clock of the upstream device. The passive port is in an intermediate position and neither broadcasts the clock source. Nor does it track the clock of the upstream device. The port status appears Passive, which means that there are two in the entire PTP network system or More than two clock sources are of comparable quality. There is also a special type of device in the PTP-enabled device. The PTP protocol packets are not processed. All devices are transparently transmitted. The device is called a Transparent Clock (TC) device. The TC device has more than one communication port. , and the communication port does not have a port status.

As shown in Figure 1, it is a schematic diagram of device connection and port status supporting PTP protocol. The clock of the OC1 device is the most advanced clock, which is the master clock of the entire network system, and the communication port of the OC1 device has the port status of Master. Port 1 of the BC1 device is connected to the master port of the OC1 device. The port status is Slave. Port 1 is the synchronization port of the BC1 device. It is used to track the clock of the upstream device OC1. For a device, only one port has the port status. It can be a slave, so the port status of the other two ports of the BC1 device can be Master or Passive. The Master is used as an example in Figure 1. Similarly, the port status of port 1 of BC2 is Slave, and the upstream device BC 1 is tracked. The clock status of the other two ports is Master. The TC device may exist in the path 1 - 5. The TC device can be regarded as a connection during the transmission of PTP packets. It can be seen that the communication port of the BC device and the OC device can maintain the master-slave state, and the BC device can transmit the clock; if the TC device exists in the path 1 - 5, the communication port of the TC device cannot maintain the master-slave state.

Although the TC device directly transmits the PTP protocol packet without being processed, the TC device has a time delay for the delivery of the PTP protocol packet. The transmission time of the PTP protocol packet inside the device is called the dwell time. The time-to-time of the PTP protocol packets in each TC device is increased. As a result, the time difference of PTP packets in the first-end device of the entire network system is large. . When transmitting a PTP protocol packet, the TC device must correct the sending time of the PTP protocol packet according to the dwell time. Only the modified PTP protocol packet will be accurate. The entire network system is a PTP network in the actual sense. system.

The TC device determines the dwell time of the PTP protocol according to the system clock frequency, so the factor that affects the calculation accuracy of the dwell time is the frequency. One method is that the TC device takes the oscillation frequency of the internal crystal as the standard, and the calculation accuracy of the dwell time can only be achieved by this method.

0.02%, lms will produce 200ns error, too large error can not meet PTP protocol message Time synchronization in the device. Another method is that the TC device proposed by IEEE 1588 should be synchronized with the upstream device. As long as the TC device synchronizes with the high-precision clock transmitted by the upstream device, the calculated dwell time is accurate. However, the prior art does not provide a method for determining the synchronization port of the TC device. The synchronization port is a port used to track the clock of the upstream device, and the port state of the synchronization port is siave. Summary of the invention

Embodiments of the present invention provide a method and a device for determining a bypass port of a clock-through device, and a synchronization port is determined for a punch-through clock device.

An embodiment of the present invention provides a method for determining a synchronization port of a TC device, including: acquiring a clock information delivery message received by at least one port of the TC device; determining an optimal clock source according to the clock information transmission message;

When the optimal clock source is better than the local clock source of the TC device, the port that receives the clock information corresponding to the optimal clock source is determined as the synchronization port.

The embodiment of the present invention further provides a device for determining a synchronization port of a TC device, including: a first acquiring unit, configured to acquire a clock information delivery message received by at least one port of the TC device;

a calculating unit, configured to determine an optimal clock source according to the clock information delivery message acquired by the first acquiring unit;

The first determining unit is configured to determine, when the optimal clock source is better than the local clock source of the TC device, that the port that receives the clock information delivery message corresponding to the optimal clock source is a synchronous port.

An embodiment of the present invention provides a method for determining a synchronization port of a TC device, including: acquiring a monitoring result of a port of a TC device to track an indication of an upstream device; and receiving, according to the monitoring result, an indication of the tracking upstream device The port of the packet is determined to be the sync port.

An embodiment of the present invention further provides another apparatus for determining a synchronization port of a TC device, including:

a second acquiring unit, configured to acquire a tracking upstream device monitored by a port of the TC device Indicate the monitoring result of the message;

And a second determining unit, configured to determine, according to the monitoring result obtained by the second acquiring unit, that the port that receives the tracking upstream device indication packet is a synchronization port.

The embodiment of the present invention determines an optimal clock source according to the clock information transmission text received by the at least one port of the TC device, and when the optimal clock source is superior to the local clock source of the TC device, the corresponding clock source is received. The port of the clock information transmission packet is determined to be the synchronization port. The port that receives the indication of the upstream device indication is monitored by the port of the TC device. Both of these methods implement the determination of the synchronization port for the TC device, so that the TC device can accurately calculate the PTP packet residence time and meet the time synchronization requirements of the PTP network. DRAWINGS

FIG. 1 is a schematic diagram of a connection and port state of a device supporting a PTP protocol in the prior art; FIG. 2 is a flowchart of determining a synchronization port and a port state of a TC device according to Embodiment 1 of the present invention;

3 is a flowchart of determining a synchronization port and a port status of a TC device according to Embodiment 2 of the present invention;

4 is a flowchart of a method for determining a synchronization port of a first TC device according to an embodiment of the present invention;

FIG. 5 is a block diagram of a device for determining a synchronization port of a first TC device according to an embodiment of the present disclosure;

6 is a flowchart of determining a synchronization port and a port status of a TC device according to Embodiment 3 of the present invention;

FIG. 7 is a flowchart of a method for determining a synchronization port of a second TC device according to an embodiment of the present invention;

FIG. 8 is a block diagram of a second apparatus for determining a synchronization port of a TC device according to an embodiment of the present invention. detailed description

The embodiment of the invention provides a method and a device for determining a synchronization port of a TC device, and how to determine a synchronization port for the TC device, so that the clock of the TC device can achieve an ideal precision, so that the TC device can further implement the PTP protocol packet. Accurate calculation of dwell time. The following is a detailed description of several specific embodiments.

Embodiment 1 is as follows:

The first embodiment provides a method for statically determining the status of the synchronization port and the port. For one

For the TC device, the announcement message in the PTP protocol packet is not processed. The announce message is a clock information transmission message between all the devices in the network system. The OC device and the BC device both process the announce message and trigger the BMC algorithm according to the clock information carried in the announce message to determine the network system. The optimal clock source, the port status of the ports in the OC device and the BC device is also determined. If the port of the device can have the port status, if the port broadcasts the optimal clock source to the entire network, the port status is Master; if the port tracks the optimal clock of the upstream device, the port status is Slave; The optimal clock source is not broadcast, and the optimal clock of the upstream device is not tracked, and the port state is Passive.

The method for determining the synchronization port and the port status of the TC device provided by the first embodiment of the present invention first sets the designated port of the TC device. If the designated port is a device port of the TC device, the TC device works in the external synchronization mode; The port is the internal crystal port of the TC device, which is equivalent to canceling the designation of the TC device synchronization port. The TC device operates in the internal crystal oscillator mode. After the device port of the TC device is configured as the designated port, you need to obtain the announcement message received by the specified port, and analyze the clock information carried in the announce message, but do not need to process other ports in the TC device. Transparently transmitted announce packets. On other ports of the TC device, the announce message still maintains the nature of transparent transmission. When the specified port is set, the designated port also has the port status.

As shown in FIG. 2, a method for determining a synchronization port and a port status of a TC device according to Embodiment 1 of the present invention includes the following steps:

S201. Set a designated port of the TC device. The designated port can be any device port of the TC device or an internal crystal oscillator port. The device port and the internal crystal oscillator port of the TC device can be uniformly numbered, distinguished according to a unique number, or according to the device port and the internal crystal port. The MAC address is distinguished.

5202, determining whether the TC device works in the external synchronization mode according to the number or MAC address of the designated port. If the designated port is a device port of the TC device, the TC device works in an external synchronization mode, and the designated port is a TC. The quasi-synchronous port of the device continues to execute S203; if the designated port is the internal crystal oscillator port of the TC device, the TC device operates in the internal crystal oscillator mode, and the process proceeds to S208.

5203: Acquire the announce packet received by the specified port, and obtain the announce packet received by the specified port, and then start the BMC algorithm for the announce packet sent by the specified port, and determine the designation according to the calculation result. Whether the clock source determined by the announce message sent by the port is better than the local clock source. The local clock source refers to the internal crystal oscillator of the TC device. If yes, execute S204. Otherwise, execute S206.

5204. Determine that the designated port is a synchronous port, and set the port status of the designated port to Slave.

5205. The TC device enters the tracking state, tracks the sending port of the received message received by the designated port, and continuously diagnoses the clock source information of the designated port, and returns to S203.

The TC device enters the tracking state, that is, the clock of the TC device is synchronized with the upstream device.

5206. Set the port status of the designated port to Passive.

5207, the TC device enters a hold or free oscillation state, and continuously diagnoses the clock source information of the designated port, and returns to execute S203.

When the TC device enters the hold state, the clock of the upstream device tracked by the TC device is lost. However, because the device has the "short-term memory" capability, the "temporary short-term memory" is used to correct the oscillation frequency of the internal crystal oscillator, and the output clock quality and tracking state. The quality of the clock is close, so it is called the hold state; the TC device enters the free oscillation state, which means that the TC device oscillates freely according to the oscillation frequency of the internal crystal oscillator. When the TC device enters the hold state, After a period of time beyond the ability of "short-term memory", it will enter a state of free oscillation.

S208, the TC device enters a free oscillation state, and the process ends.

In the first embodiment, when the designated port of the TC device is set, and when the designated port is a non-inner crystal port and the clock source of the specified port is better than the local clock source, it is determined that the designated port is a synchronous port, and the method is simple and guaranteed. The TC device is synchronized with the better clock source.

The second embodiment is as follows:

The second embodiment provides a method for dynamically determining the synchronization port and port status according to the announce message. The device obtains the announce packet received by all the device ports of the TC device, analyzes the announcement, starts the BMC algorithm, and calculates the optimal clock source based on the clock information carried in the announce message. The optimal clock source is better than the TC. The local clock source of the device determines that the port that receives the announce packet corresponding to the optimal clock source is the synchronous port, so that the TC device tracks the sending port of the optimal clock source. The method for dynamically determining the synchronization port of the TC device requires the TC device to process the announce text received by the port. Although the TC device processes the announce text, it does not broadcast the optimal clock source like the BC device, so the TC The synchronization port determined by the device and the port status of all other ports will not be Master.

As shown in FIG. 3, a method for determining a synchronization port and a port state of a TC device according to Embodiment 2 of the present invention includes the following steps:

5301. Obtaining the announce message received by all the device ports of the TC device, and obtaining the announce message received by all the device ports.

5302. The BMC algorithm is started on the announce message sent by all the device ports, and the optimal clock source is calculated. The port that receives the announce message corresponding to the optimal clock source is the quasi-synchronous port of the TC device.

5303. Determine whether the optimal clock source is better than the local clock source. If yes, perform S304, otherwise execute S307.

5304. Determine that the reporting port of the announce message corresponding to the optimal clock source is a synchronous port.

5305, set the port status of the synchronization port to Slave, and the port status of the asynchronous port to Passive. 5306. The TC device enters the tracking state, and tracks the sending port of the received packet received by the synchronous port, and continuously diagnoses the clock source information of all device ports, and returns to S301.

5307, Set the port status of all device ports to Passive.

5308, the TC device enters the hold or free oscillation state, and continuously diagnoses the clock source information of all device ports, and returns to execute S301.

The method for dynamically determining the synchronization port and port status of the TC device provided by the second embodiment of the present invention can capture the optimal clock source in the current network system and keep the TC device synchronized with the optimal clock source at all times.

Of course, the receiving device can also indicate the received message on the device port of the TC device, and the BMC algorithm is started to calculate the optimal clock source. When the optimal clock source is better than the local clock source of the TC device, it is determined that the received message is received. The port of the "announce" corresponding to the optimal clock source is the synchronous port, the port status of the synchronous port is Slave, and the port status of the asynchronous port is Passive; if the local clock source is better than the optimal clock source, the report is received. The port status of the device port of the received announcement packet is Passive.

According to the solution provided by the first embodiment and the second embodiment, the embodiment of the present invention provides a method for determining a synchronization port of a TC device. As shown in FIG. 4, the method includes:

S401: Obtain a clock information delivery message received by at least one port of the TC device.

5402, the optimal clock source is determined according to the clock information transmission text.

The embodiment of the present invention further provides a device for determining a synchronization port of a TC device, which is disposed in the TC device, as shown in FIG. 5, and includes:

The first obtaining unit 501 is configured to acquire a clock information delivery message received by the at least one port of the TC device.

The calculating unit 502 is configured to determine an optimal clock source according to the clock information delivery message acquired by the first obtaining unit 501;

The first determining unit 503 is configured to determine, when the optimal clock source is better than the local clock source of the TC device, the port that receives the clock information delivery message corresponding to the optimal clock source. For the sync port.

The clock information delivery message may be an announce message.

The third embodiment is as follows:

The third embodiment provides a method for dynamically determining the status of the synchronization port and the port according to the synchronization (sync) message. The TC device keeps track of the upstream device, that is, it tracks the sync message sent by the upstream device. The sync message is used to track the upstream device indication packet. In a PTP network system, if a port on a device receives a sync packet, the port status of the send port of the sync packet is definitely Master. Because the master port broadcasts the optimal clock source information in the network system, it is reasonable and feasible to determine that the port that receives the sync message is a synchronous port and directly track the send port of the sync message.

As shown in FIG. 6, a method for determining a synchronization port and a port state of a TC device according to Embodiment 3 of the present invention includes the following steps:

5601. Obtain the monitoring result of the sync packet monitored by the port of the TC device. The sync packet is a tracking upstream device indication packet sent by the upstream device, and the sync packet is used for clock synchronization. The synchronization packet is detected by the port of the TC device, and the monitoring result of the received synchronization packet is periodically reported. Ways to get monitoring results.

5602. Determine whether there is a port that receives the sync message. If yes, execute S603. Otherwise, execute S607.

5603. Determine that the port that receives the sync packet is a synchronous port, and set the port status to Slave. The port status of the non-synchronous port is Passive.

5604. The TC device enters the tracking state and tracks the port on which the upstream device sends the sync packet.

5605. Determine whether the sync message of the synchronization port is lost. If yes, execute S606. Otherwise, execute S605 repeatedly.

When the sync port of the port is not receiving the sync packet within a certain period of time, the sync packet is lost. The cause of the sync packet loss may be network interruption or receiving error.

5606, the TC device enters the hold state, and continuously diagnoses the sync message of the port, and returns to execute S601. 5607. Set the port status of the TC device port to Passive.

5608, the TC device enters the hold or free-oscillation state, and continuously diagnoses the sync of the port, and returns to execute S601.

The method for determining the synchronization port and the port status of the TC device provided by the third embodiment of the present invention directly determines that the port that receives the sync packet is a synchronous port, and the port that the upstream device sends the sync packet is tracked, and the method is simple and flexible, and can be Keep the TC device synchronized with the optimal clock source at all times.

According to the solution provided by the third embodiment, the embodiment of the present invention provides a method for determining a synchronization port of a TC device. As shown in FIG. 7, the method includes the following steps:

5701. Obtain a monitoring result of the port of the TC device to track the indication of the upstream device indication.

5702. According to the monitoring result, the port that receives the indication of the upstream device indication is determined as the synchronization port.

The embodiment of the present invention further provides a synchronization port determining device for the TC device, which is disposed in the TC device, as shown in FIG. 8, and includes:

The second obtaining unit 801 is configured to obtain a monitoring result of the tracking upstream device indication message monitored by the port of the TC device.

The second determining unit 802 is configured to determine, according to the monitoring result obtained by the second obtaining unit 801, a port that receives the tracking upstream device indication message as a synchronization port.

The tracking upstream device indication packet may be a sync packet.

The embodiment of the present invention provides a method for determining a synchronization port of a TC device, and a method for determining an optimal clock source according to a clock information transmission message received by at least one port of the TC device, and the optimal clock source is superior to the TC device. When the local clock source is used, the port that receives the clock information corresponding to the optimal clock source is determined as the synchronization port; and the other method can obtain the monitoring result of the tracking upstream device indication packet monitored by the port of the TC device. The port that receives the tracking upstream device indication packet is determined as the synchronization port. The synchronization port determination method implements how to determine the synchronization port for the TC device, so that the clock of the TC device can achieve the desired accuracy, so that the TC device can accurately calculate the PTP protocol packet residence time.

Through the description of the above embodiments, those skilled in the art can clearly understand The invention can be implemented by hardware or by means of software plus a necessary general hardware platform. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which may be stored in a non-volatile storage medium (which may be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including several The instructions are for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention. It is within the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

Rights request

A method for determining a synchronization port of a punch-through clock device, comprising: acquiring a clock information transmission message received by at least one port of a punch-through clock TC device;

Determining an optimal clock source according to the clock information delivery message;

2. The method of claim 1, further comprising:

When the local clock source of the TC device is better than the optimal clock source, at least one port of the TC device is set to a negative state.

3. The method of claim 2, wherein at least one port of the TC device is a non-internal crystal port of the TC device.

The method of claim 3, wherein when the clock information transmission message received by one port of the TC device is obtained, the method for determining the optimal clock source according to the clock information transmission message is: The clock source determined according to the clock information received by the one port is used as the optimal clock source.

The method of claim 2, wherein when the clock information delivery message received by the two or more ports of the TC device is acquired, determining the synchronization port further comprises: placing the two or more ports The asynchronous port is set to a negative state.

The method according to any one of claims 1 to 5, wherein the clock information transmission message comprises an announcement message.

A device for determining a synchronization port of a TC device, comprising: a first acquiring unit: configured to acquire a clock information delivery message received by at least one port of the TC device;

The first determining unit is configured to: when the optimal clock source is better than the local clock source of the TC device, receive the port of the clock information corresponding to the optimal clock source Determined as a sync port.

A method for determining a synchronization port of a TC device, comprising: acquiring a monitoring result of a port of the TC device to track an indication of the upstream device; and receiving, according to the monitoring result, the tracking upstream device indication The port of the text is determined to be the sync port.

9. The method of claim 8, further comprising:

The synchronization port is set to the slave state, and the asynchronous port of the TC device is set to the passive state.

10. The method according to claim 9, further comprising: if no port receives the tracking upstream device indication message, setting the port of the TC device to a negative state.

The method according to claim 8, 9 or 10, wherein the tracking upstream device indication message comprises a synchronous sync message.

A device for determining a synchronization port of a TC device, comprising: a second acquiring unit: configured to acquire a monitoring result of a tracking upstream device indication message monitored by a port of the TC device;

The second determining unit is configured to determine, according to the monitoring result obtained by the second acquiring unit, a port that receives the tracking upstream device indication message as a synchronization port.