WO2012122813A1 - 一种时钟源设备切换选择方法、系统及装置 - Google Patents

一种时钟源设备切换选择方法、系统及装置 Download PDF

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Publication number
WO2012122813A1
WO2012122813A1 PCT/CN2011/082211 CN2011082211W WO2012122813A1 WO 2012122813 A1 WO2012122813 A1 WO 2012122813A1 CN 2011082211 W CN2011082211 W CN 2011082211W WO 2012122813 A1 WO2012122813 A1 WO 2012122813A1
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Prior art keywords
source device
clock source
clock
valid
address information
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PCT/CN2011/082211
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English (en)
French (fr)
Inventor
王斌
刘东甲
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中兴通讯股份有限公司
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Application filed by 中兴通讯股份有限公司 filed Critical 中兴通讯股份有限公司
Priority to EP11861085.6A priority Critical patent/EP2688240B1/en
Publication of WO2012122813A1 publication Critical patent/WO2012122813A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0641—Change of the master or reference, e.g. take-over or failure of the master
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0658—Clock or time synchronisation among packet nodes
    • H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
    • H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays

Definitions

  • the present invention relates to the field of communications technologies, and more particularly to a clock source device switching selection method, system and apparatus. Background technique
  • Precision Time Protocol (PTP) -
  • the IEEESTD1588 protocol is one of the key technologies in the field of time and frequency synchronization control.
  • the 1588 protocol stipulates that the clock source device is considered to be stable when the number of received advertisements of a clock source device reaches two in each of the four notifications.
  • the general clock slave device records five such clock source devices as alternative sources, and then selects the highest priority one as the clock source device of the current system clock by the Best Master Clock Algorithm (BMC).
  • BMC Best Master Clock Algorithm
  • the clock slave determines that there is a problem with the link between the clock source device and then switches to the best of the alternate clock source devices.
  • the embodiment of the invention provides a clock source device switching selection method, system and device, which are used to solve the problem that the clock source device may not be able to select an effective clock source device because the upstream path of the clock source device is unreachable when the existing clock source device is switched.
  • a clock source device switching selection method includes:
  • the clock When receiving the advertisement packet sent by the clock source device, the clock sends a link detection packet to the clock source device.
  • the clock source device When the clock source device receives the detection feedback message fed back by the clock source device according to the link detection packet, it is confirmed that the clock source device is a valid clock source device;
  • the clock slave device When the clock slave device confirms that the valid clock source device is a stable clock source device, adding the valid clock source device to the candidate clock source device list;
  • a clock device includes: a receiving module, a sending module, a determining module, and a selecting module; the receiving module is configured to receive an advertisement message sent by the clock source device and a detection feedback of the receiving clock source device according to the link detection message feedback Message
  • a sending module configured to send the link detection packet to a clock source device when receiving the advertisement packet
  • a determining module configured to: when the detection feedback message is received, confirm that the clock source device is a valid clock source device; and confirm that the valid clock source device is a stable clock source device, add the valid clock source device to the device Select the clock source device list;
  • the selection module is used to select from the list of candidate clock source devices when the clock source device needs to be switched.
  • a clock source device switching selection system comprising: a clock slave device and a clock source device; the clock slave device, configured to send a link detection message to the clock source device when receiving the advertisement message sent by the clock source device; Receiving, by the clock source device, the clock source device is a valid clock source device according to the detection feedback message fed back by the link detection packet; and confirming that the valid clock source device is a stable clock source device, A valid clock source device is added to the list of candidate clock source devices; when it is required to switch the clock source device, select from a list of candidate clock source devices;
  • the clock source device is configured to send a detection feedback message to the clock slave device when receiving the link detection packet sent by the clock slave device.
  • the clock source device switching selection method, system, and device provided by the embodiment of the present invention, when the clock slave device receives the advertisement packet of the clock source device, initiates a link detection packet to detect whether the uplink is normal.
  • the clock source device is used as the effective clock source device, and further determined that the downlink communication is stable, the clock is used as an alternative clock.
  • the source device is selected for use when switching.
  • the handshake mode is adopted to ensure that the uplink and downlink links between the clock source device and the clock slave device are bidirectionally normal, and the clock source device that fails to select the link is avoided, which affects the normal clock synchronization of the clock slave device. get on.
  • the solution of the embodiment of the present invention does not require more network resource overhead, and can ensure that the clock slave device can correctly select the master device or perform other synchronization mode selection when the network has an abnormal situation such as a single pass with little resource overhead, instead of It will directly cause the error of time source selection, and ensure that the clock is synchronized from the device clock.
  • FIG. 1 is a schematic structural diagram of a clock source device switching selection system according to an embodiment of the present invention
  • FIG. 2 is a schematic flowchart of a clock source device switching selection method according to an embodiment of the present invention
  • FIG. 3 is a clock source device switching selection device according to an embodiment of the present invention
  • the embodiment of the present invention provides a clock source device switching selection method, which is used for time and frequency synchronization using a 1588 clock synchronization protocol, and performs validity determination on a clock source device when a clock slave device is connected to a clock source device to correctly perform a clock source.
  • Device Selection The method implements bidirectional communication link detection by means of a detection and detection feedback mechanism between the device and the clock source device by the clock to ensure the validity of the clock source device selected by the clock slave device.
  • the system structure for implementing the switching method of the clock source device is as shown in FIG. 1.
  • the system includes: a clock source device and a clock slave device.
  • a clock slave device and two clock source devices are included as an example.
  • the clock source device 1 and the clock slave device communicate with each other through the cloud network 1 and the cloud network 3, and the clock source device 2 and the clock slave device communicate with each other through the cloud network 2 and the cloud network 3.
  • the clock source device may be a clock source device using the precise clock synchronization protocol, the 1588 protocol, and the clock slave device is a clock clock slave device using the precise clock synchronization protocol, the 1588 protocol.
  • the clock source device switching selection method provided by the embodiment of the present invention is as shown in FIG. 2, and includes the following steps:
  • Step 101 The clock source device sends an advertisement message to the clock slave device.
  • the system shown in Figure 1 is the active/standby clock source network with two clock sources. Both clock source device 1 and clock source device 2, which serve as the clock source, send advertisement packets to the clock slave device.
  • the advertisement packet sent by the clock source device 1 reaches the clock slave device through the cloud network 1 and the cloud network 3.
  • the advertisement packet sent by the clock source device 2 reaches the clock slave device through the cloud network 2 and the cloud network 3, and the clock slave device can Select which clock source device to use as the primary clock source device, and the other as the alternate clock source device to select when switching selection.
  • the clock slave device can select according to the priority of the clock source determined by the BMC.
  • Step 102 When the clock receives the announcement message sent by the clock source device, the clock sends a link detection packet to the clock source device.
  • the device When the device receives the advertisement packet from the clock source device for the first time, the device sends a link detection packet to the clock source device in the unicast or multicast mode according to the set detection period.
  • the clock carries the clock's own address information and the address information of the clock source device.
  • the clock slave device sends a link detection packet to the clock source device according to the set detection period. This detection period may be the same as or different from the transmission period of the advertisement.
  • the clock slave device after receiving the advertisement message of the clock source device 1 and the clock source device 2, the clock slave device sends a link detection message to the clock source device 1 and the clock source device 2, respectively.
  • Step 103 When receiving the link detection packet, the clock source device sends a detection feedback message to the clock slave device.
  • the clock source device receives the link detection packet sent by the clock slave device, and feeds back the detection feedback packet to the clock slave device to notify the clock slave device that the link is normal. Specifically, the clock source device determines, according to the address information of the clock source device carried in the link detection packet, the clock slave device address information carried in the link detection packet when the link detection packet is sent to the link detection packet. The clock sends a detection feedback message from the device. The sent detection feedback message carries the address information of the clock slave device and the address information of the clock source device. If the clock source device does not receive the link detection packet, the detection feedback packet will not be sent. The clock source device can also send and detect by unicast or multicast. The feedback packet is sent to the device to receive the link detection packet sent by the device. The uplink is normal.
  • the clock source device can determine whether it is a packet sent to itself according to the address information of the clock source device in the link detection packet, so as to be able to match and discard packets that are not in its own domain, especially for the multicast mode transmission chain. Road detection messages, this kind of matching is especially important.
  • the clock feedback device returns a detection feedback message to the clock slave device.
  • Step 104 When the clock receives the detection feedback message from the device, confirm that the clock source device is a valid clock source device.
  • the clock source device When the clock source receives the detection feedback message from the device, the clock source device considers that the uplink and downlink between the clock source device and the clock source device are normal. That is, the clock source device is a valid clock source. device. Specifically, the clock receives the detection feedback message from the device, and obtains the address information of the clock slave device and the address information of the clock source device carried in the detection feedback message, and the address information of the clock slave device and the address of the clock source device. When the information is matched with the address information of the clock in the link detection packet sent by the device and the address information of the clock source device, the clock source device is determined to be a valid clock source device and can be used as the time source of the clock slave device.
  • the clock slave device When the clock slave device does not receive the detection feedback packet from the clock source device within the set feedback timeout period, the uplink between the clock source device and itself is abnormal.
  • the clock source device may be offline or faulty. Etc. At this time, the clock source device is not available, and is not a valid clock source device that can be used as a clock slave device time source.
  • the clock slave when the clock slave receives the detection feedback message fed back by the clock source device 1, the clock source device 1 is a valid clock source device, and the clock slave device does not receive the clock.
  • step 106 The device, if yes, performs step 107; otherwise, step 106 is performed.
  • the device further performs stability determination on the valid clock source device.
  • the clock slave device determines that the valid clock source device is a stable clock source device when it receives a notification packet of not less than the set number from the valid clock source device within the set receiving period. Through the stability determination, it is further determined whether the transmission and reception of the valid clock source device advertisement packet is stable, and whether it is a reliable clock source.
  • the clock slave device further determines whether a set number of advertisement messages are received from the clock source device 1 within a set reception period, for example, two notification message transmission periods are received, and two are received. If the packet is advertised, the clock source device is considered to be a stable clock source device. It is assumed that the clock slave device receives a notification packet of not less than the set number from the clock source device 1, for example, if three notification packets are received, which is greater than the set number of 2, the clock source device 1 is considered to be a stable effective clock source device. .
  • Step 106 The valid clock source device is not added to the list of candidate clock source devices, and the current process is ended.
  • the stability of the valid clock source device fails to determine that the valid clock source device is not a stable clock source device, it can be excluded from the list of alternate clock source devices, and is no longer selected when the clock is switched from the device.
  • the clock slave device since it does not receive the feedback detection feedback message, it is not used as an effective clock source.
  • the device does not perform stability determination and does not add the clock source device 2 to the list of candidate clock source devices.
  • Step 107 Add the determined valid clock source device to the list of candidate clock source devices.
  • the clock slave device determines that the valid clock source device is a stable clock source device when it receives a notification packet of not less than the set number from the valid clock source device within the set receiving period, and then determines according to the set priority algorithm.
  • the priority of the valid clock source device, and the valid clock source device is added to the list of candidate clock source devices in order of priority.
  • the device is a stable clock source device. When it is a reliable time source, it can be used as an alternate clock source device. It can be used when the clock slave switches the clock source.
  • the BMC is used to determine the priority of the clock source device 1 of the active clock source device, and it is added to the list of candidate clock source devices in order of priority.
  • Step 108 When the clock slave device needs to switch the clock source device, select from the list of candidate clock source devices.
  • the clock source device with the highest priority can be selected from the list of candidate clock source devices to switch.
  • the clock source devices in the list of alternate clock source devices are all clock source devices with normal uplink and downlink links, so that clock source devices that are not connected to the uplink and cannot be connected normally are not selected.
  • the clock slave device cannot receive The detection feedback message is sent to the clock source device 2, and therefore, the clock source device 2 is not selected. If the clock source used by the current clock slave device is the clock source device 2, the clock slave device selects the clock source device 1 to be switched as the clock source. If the clock source used by the current clock slave device is the clock source device 1, the switch does not occur. Even if the priority of the clock source device 2 is determined according to the stability and the BMC determines the priority of the clock source device, the clock slave device does not select. Switching to clock source device 2 as the clock source, because the clock source device 2 link is single-passed at this time, causing the clock slave device to be unable to synchronize with the clock source.
  • the clock source device switching selection system is provided by the embodiment of the present invention.
  • the structure of the system is shown in FIG. 1 and includes: a clock slave device and a clock source device.
  • the clock slave device and the clock source device can be set as many as needed.
  • the clock slave device is configured to set the clock source when receiving the advertisement packet sent by the clock source device.
  • the device sends a link detection packet.
  • the clock source device receives the detection feedback message from the link detection packet, it confirms that the clock source device is a valid clock source device; and confirms that the valid clock source device is a stable clock source device. Add a valid clock source device to the list of alternate clock source devices; when you need to switch clock source devices, select from the list of alternate clock source devices.
  • the clock source device is configured to send a detection feedback message to the clock slave device when receiving the link detection packet sent by the clock slave device.
  • the clock slave device is specifically configured to: when receiving the advertisement packet sent by the clock source device for the first time, start sending the link detection packet to the clock source device in a unicast or multicast manner according to the set detection period.
  • the transmitted link detection packet carries the address information of the clock slave device and the address information of the clock source device.
  • the clock source device is specifically configured to: receive a link detection packet sent by the clock slave device, and determine, according to the address information of the clock source device carried in the link detection packet, a link detection packet sent to the link detection packet.
  • the clock that is carried in the link detection packet sends a detection feedback message from the clock corresponding to the address information of the device.
  • the sent detection feedback message carries the address information of the clock slave device and the address information of the clock source device.
  • the clock slave device is specifically configured to: receive the detection feedback message, and carry the clock information of the clock slave device, the address information of the clock source device, and the clock in the link detection packet sent by the slave device When the address information and the address information of the clock source device match, it is determined that the clock source device is a valid clock source device.
  • the clock slave device is specifically configured to: determine that the valid clock source device is a stable clock source device when receiving an advertisement packet that is not less than a set number from the valid clock source device within the set receiving period. And determining, according to the set priority algorithm, the priority of the valid clock source device, and adding the valid clock source device to the candidate clock source device list according to the priority order, based on the foregoing clock source device switching selection system provided by the embodiment of the present invention, Implementation of the invention
  • the example also provides a clock device, which can be used as a clock slave device or as a clock master device, and its structure is shown in FIG. 3.
  • the clock device shown in FIG. 3 When the clock device shown in FIG. 3 is used as a clock slave device, it includes: a receiving module 10, a transmitting module 20, a determining module 30, and a selecting module 40. among them,
  • the receiving module 10 is configured to receive an advertisement message sent by the clock source device and a detection feedback message that is received by the clock source device according to the link detection message.
  • the sending module 20 is configured to send a link detection message to the clock source device when receiving the advertisement message.
  • the determining module 30 is configured to: when receiving the detection feedback message, confirm that the clock source device is a valid clock source device; and confirm that the valid clock source device is a stable clock source device, add the valid clock source device to the candidate clock source. In the device list.
  • the selection module 40 is configured to select from the list of candidate clock source devices when the clock source device needs to be switched.
  • the sending module 20 is configured to: when the receiving module 10 receives the advertisement packet sent by the clock source device for the first time, the receiving module 10 starts to send the link to the clock source device in a unicast or multicast manner according to the set detection period.
  • the detection packet sends the link detection packet carrying the address information of the clock slave device and the address information of the clock source device.
  • the determining module 30 includes: a first determining module 301, a second determining module 302, and a list updating module 303.
  • the first determining unit 301 is configured to receive the detection feedback message, and the clock information of the clock slave device, the address information of the clock source device, and the address information of the clock slave device in the transmitted link detection message, and the clock When the address information of the source device matches, it is determined that the clock source device is a valid clock source device.
  • the second determining unit 302 is configured to determine that the valid clock source device is a stable clock when receiving an advertisement packet that is not less than the set number from the valid clock source device within the set receiving period. Source device.
  • the list updating unit 303 is configured to determine, when the second determining unit 302 determines that the valid clock source device is a stable clock source device, the priority of the valid clock source device according to the set priority algorithm.
  • the receiving module 10 and the transmitting module 20 are included. among them:
  • the receiving module 10 is configured to receive a detection feedback message sent by the clock from the device.
  • the sending module 20 is configured to send an advertisement message to the clock slave device, and send the detection feedback message to the clock slave device when the receiving module 10 receives the link detection message sent by the clock slave device. Specifically, when the receiving module 10 receives the link detection packet sent by the clock source device, and determines the link detection packet sent to the clock source device according to the address information of the clock source device carried in the link detection packet. The clock that is carried in the link detection packet sends a detection feedback message from the clock corresponding to the address information of the device. The sent detection feedback message carries the address information of the clock slave device and the address information of the clock source device.
  • the clock source device switching selection method, system and device provided by the embodiment of the present invention when the clock slave device receives the advertisement packet of the clock source device, initiates a link detection packet to detect whether the uplink is normal.
  • the clock source device is regarded as an effective clock source device, and further determined to be stable, and used as an alternate clock source device for switching. . If the detection feedback packet returned by the clock source device is incorrectly received, you can know that the uplink is unreachable. You cannot use the clock source device as the clock source.
  • the handshake mode is adopted to ensure that the uplink and downlink links between the clock source device and the clock slave device are bidirectionally normal, and the clock source device that fails to select the link is avoided, which affects the normal clock synchronization of the clock slave device. get on.
  • the clock slave device can correctly select the master device or perform other synchronization mode selection without directly causing the error of the time source selection, and ensuring that the clock is synchronized from the device clock.

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  • Computer Networks & Wireless Communication (AREA)
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Abstract

本发明公开了一种时钟源设备切换选择方法、系统及装置，其中方法包括：时钟从设备接收到时钟源设备发送的通告报文时，向时钟源设备发送链路检测报文；时钟从设备接收到时钟源设备根据所述链路检测报文反馈的检测反馈报文时，确认该时钟源设备为有效时钟源设备；时钟从设备确认所述有效时钟源设备为稳定时钟源设备时，将所述有效时钟源设备加入备选时钟源设备列表中；时钟从设备需要切换时钟源设备时，从备选时钟源设备列表中选择。通过链路检测报文和检测反馈报文检测上行链路的通信状况，从而找到可靠的时钟源设备，保证时钟从设备时钟同步的正确性。

Description

一种时钟源设备切换选择方法、 系统及装置 技术领域
本发明涉及通信技术领域， 尤指一种时钟源设备切换选择方法、 系统 及装置。 背景技术
精确时钟同步协议 ( Precision Time Protocol, PTP ) —— IEEESTD1588 协议是在时间和频率同步控制领域中的重要技术之一。 1588协议规定了每 台设备在 4个通告（ announce )报文时间内，收到某个时钟源设备的 announce 报文数量达到 2个， 则认为时钟源设备稳定。 一般时钟从设备记录五个这 样的时钟源设备为备选源， 然后通过最佳时钟算法 （ Best Master Clock Algorithm, BMC )选出其中优先级最高的一个作为当前系统时钟的时钟源 设备。 当 announce才艮文接收超时， 时钟从设备则确定与时钟源设备之间的 链路发生问题， 随即切换到备用时钟源设备中最好的一个。
在实际的网络应用上， 当收到 announce报文时， 只能证明时钟从设备 和时钟源设备之间的下行传输正常， 却不能保证上行传输正常， 这就会导 致在网络出现局部故障的情况下， 虽然下行方向能够根据收到的 announce 报文选择最高优先级的一个时钟源设备， 但是这个时钟源设备实际上可能 上行传输方向不畅通。 而且如果网络中尚有其他可用的时钟源设备， 但由 于根据 announce报文确定的优先级， 时钟从设备会一直试图连接优先级最 高的这一个时钟源设备， 导致时钟从设备一直无法锁定时钟源设备。
不论是 E2E (端到端 )方式还是 P2P ( Peer-to-Peer, 点对点）方式， 这 种链路单通的设备， 都会发生这种时钟从设备一直无法连接并锁定时钟源 设备的问题。 这种现象在个别设备附近网络出现问题时， 可能会导致局部 的问题扩散至全网，使得时钟从设备一直无法锁定， 因此，仅根据 announce 报文来判断时钟源设备的有效性将会导致网络中存在时钟从设备无法连接 时钟源设备， 从而导致通信中断等问题， 导致时钟源设备的有效性判定准 确率降低， 使得使用 1588协议的实际网络环境在应用上存在的风险大大增 加。 发明内容
本发明实施例提供一种时钟源设备切换选择方法、 系统及装置， 用以 解决现有时钟源设备切换选择时由于时钟源设备上行通路不通， 导致可能 不能选择到有效时钟源设备的问题。
一种时钟源设备切换选择方法， 包括：
时钟从设备接收到时钟源设备发送的通告报文时， 向时钟源设备发送 链路检测报文；
时钟从设备接收到时钟源设备根据所述链路检测报文反馈的检测反馈 报文时， 确认该时钟源设备为有效时钟源设备；
时钟从设备确认所述有效时钟源设备为稳定时钟源设备时， 将所述有 效时钟源设备加入备选时钟源设备列表中；
时钟从设备需要切换时钟源设备时， 从备选时钟源设备列表中选择。 一种时钟设备， 包括： 接收模块、 发送模块、 确定模块和选择模块； 所述接收模块， 用于接收时钟源设备发送的通告报文和接收时钟源设 备根据链路检测报文反馈的检测反馈报文；
发送模块， 用于接收到所述通告报文时， 向时钟源设备发送所述链路 检测报文；
确定模块， 用于接收到所述检测反馈报文时， 确认该时钟源设备为有 效时钟源设备； 以及确认所述有效时钟源设备为稳定时钟源设备时， 将所 述有效时钟源设备加入备选时钟源设备列表中； 选择模块， 用于当需要切换时钟源设备时， 从备选时钟源设备列表中 选择。
一种时钟源设备切换选择系统， 包括： 时钟从设备和时钟源设备； 所述时钟从设备， 用于接收到时钟源设备发送的通告报文时， 向时钟 源设备发送链路检测报文； 接收到时钟源设备根据所述链路检测报文反馈 的检测反馈报文时， 确认该时钟源设备为有效时钟源设备； 以及确认所述 有效时钟源设备为稳定时钟源设备时， 将所述有效时钟源设备加入备选时 钟源设备列表中； 当需要切换时钟源设备时， 从备选时钟源设备列表中选 择；
所述时钟源设备， 用于接收到所述时钟从设备发送的链路检测报文时 , 向所述时钟从设备发送检测反馈报文。
本发明有益效果如下：
本发明实施例提供的时钟源设备切换选择方法、 系统及装置， 时钟从 设备接收到时钟源设备的通告报文时， 会向其发起链路检测报文， 检测上 行链路是否正常。 当根据时钟源设备返回的检测反馈报文确定上行链路通 信正常时， 才会将该时钟源设备作为有效时钟源设备， 再进一步判定其下 行链路通信的稳定后， 才会作为备选时钟源设备供切换时选择使用。 通过 链路检测反馈机制， 采用握手的方式， 确保时钟源设备和时钟从设备之间 的上下行链路双向正常， 避免了选择到链路不通的时钟源设备， 影响时钟 从设备时钟同步的正常进行。 本发明实施例方案不需要较多的网络资源开 销， 以极少的资源开销即可确保网络出现单通等异常情况的时候时钟从设 备能够正确的选择主设备或者进行其他同步方式选择， 而不会直接造成时 间源选择的错误， 保证时钟从设备时钟同步的正确。 附图说明
此处所说明的附图用来提供对本发明的进一步理解， 构成本发明的一 部分， 本发明的示意性实施例及其说明用于解释本发明， 并不构成对本发 明的不当限定。 在附图中：
图 1为本发明实施例中时钟源设备切换选择系统的结构示意图； 图 2为本发明实施例中时钟源设备切换选择方法的流程示意图； 图 3为本发明实施例中时钟源设备切换选择装置的结构示意图。 具体实施方式
为了使本发明所要解决的技术问题、 技术方案及有益效果更加清楚、 明白， 以下结合附图和实施例， 对本发明进行进一步详细说明。 应当理解， 此处所描述的具体实施例仅仅用以解释本发明， 并不用于限定本发明。
本发明实施例提供一种时钟源设备切换选择方法， 针对使用 1588时钟 同步协议进行时间和频率同步的设备， 在时钟从设备连接时钟源设备时对 时钟源设备进行有效性判定以便正确进行时钟源设备选择。 该方法通过时 钟从设备和时钟源设备之间的检测和检测反馈机制实现双向的通信链路检 测， 以保证时钟从设备选择的时钟源设备的有效性。 实现该时钟源设备切 换选择方法的系统结构如图 1 所示， 该系统包括： 时钟源设备和时钟从设 备。
例如图 1 所示， 以包括一个时钟从设备和两个时钟源设备（时钟源设 备 1和时钟源设备 2 )为例。 时钟源设备 1和时钟从设备之间通过云网络 1 和云网络 3通信，时钟源设备 2和时钟从设备之间通过云网络 2和云网络 3 通信。 其中， 时钟源设备可以是使用精确时钟同步协议一一 1588协议的时 钟时钟源设备， 时钟从设备则是使用精确时钟同步协议一一 1588协议的时 钟时钟从设备。
本发明实施例提供的时钟源设备切换选择方法， 其流程如图 2所示， 包括如下步驟：
步驟 101 : 时钟源设备发送通告报文给时钟从设备。 例如： 图 1 所示的系统为拥有两个时钟源的主备时钟源网络， 作为时 钟源的时钟源设备 1和时钟源设备 2均会向时钟从设备发送通告报文。 其 中， 时钟源设备 1发送的通告报文经云网络 1和云网络 3到达时钟从设备， 时钟源设备 2发送的通告报文经云网络 2和云网络 3到达时钟从设备， 时 钟从设备可以选择使用哪个时钟源设备作为主用的时钟源设备， 另外一个 作为备用的时钟源设备在切换选择时选用，时钟从设备可以根据 BMC确定 的时钟源的优先级进行选择。
步驟 102: 时钟从设备接收到时钟源设备发送的通告（announce )报文 时， 向时钟源设备发送链路检测报文。
时钟从设备首次接收到时钟源设备发送的通告报文时， 开始按照设定 的检测周期以单播或组播的方式向时钟源设备发送链路检测报文； 其中发 送的链路检测报文中携带时钟从设备自己的地址信息和时钟源设备的地址 信息。 时钟从设备按照设定的检测周期向时钟源设备发送链路检测报文， 这个检测周期可以与通告 ·^艮文的发送周期相同， 也可以不同。
沿用图 1所示的示例，时钟从设备接收到时钟源设备 1和时钟源设备 2 的通告报文后， 分别向时钟源设备 1和时钟源设备 2发送链路检测报文。
步驟 103: 时钟源设备接收到链路检测报文时， 向时钟从设备发送检测 反馈报文。
时钟源设备接收到时钟从设备发送的链路检测报文， 向时钟从设备反 馈检测反馈报文， 通知时钟从设备链路正常。 具体地， 时钟源设备根据链 路检测报文中携带的时钟源设备的地址信息确定是发送给自己的链路检测 报文时 , 向链路检测报文中携带的时钟从设备地址信息对应的时钟从设备 发送检测反馈报文， 发送的检测反馈报文中携带时钟从设备的地址信息和 时钟源设备自己的地址信息。 若时钟源设备未接收到链路检测报文， 则不 会发送检测反馈报文。 时钟源设备也可以采用单播或组播的方式发送检测 反馈报文， 通知时钟从设备接收到了其发送的链路检测报文， 上行链路正 常。
时钟源设备可以根据链路检测报文中的时钟源设备的地址信息确定是 否是发送给自己的报文， 以便能够匹配和丟弃不属于自己的报文， 尤其是 对于组播模式发送的链路检测报文， 这种匹配尤为重要。
沿用图 1所示的示例， 时钟源设备 1和时钟源设备 2收到链路检测报 文时， 向时钟从设备返回检测反馈报文。
步驟 104: 时钟从设备接收到检测反馈报文时，确认该时钟源设备为有 效时钟源设备。
时钟从设备接收到时钟源设备根据链路检测报文反馈的检测反馈报文 时， 认为自身与时钟源设备之间的上行和下行链路都是正常的， 即该时钟 源设备为有效时钟源设备。 具体地， 时钟从设备接收到检测反馈报文， 获 取检测反馈报文中携带的时钟从设备的地址信息、 时钟源设备的地址信息 , 当携带的时钟从设备的地址信息、 时钟源设备的地址信息与自身发送的链 路检测报文中的时钟从设备的地址信息、 时钟源设备的地址信息相匹配时， 确定该时钟源设备为有效时钟源设备， 可以作为时钟从设备的时间源。
当时钟从设备在设定的反馈超时时间内未接收到时钟源设备反馈的检 测反馈报文时， 认为时钟源设备与自身之间的上行链路不正常， 可能是时 钟源设备离线或网络故障等， 此时， 该时钟源设备不可用， 不是可以作为 时钟从设备时间源的有效时钟源设备。
沿用图 1所示的示例， 时钟从设备接收到了时钟源设备 1反馈的检测 反馈报文， 则时钟源设备 1 为有效时钟源设备， 时钟从设备未接收到时钟
设备， 若是， 执行步驟 107; 否则， 执行步驟 106。 设备， 进一步对该有效时钟源设备进行稳定性判定。 时钟从设备判断出在 设定的接收周期内从有效时钟源设备接收到了不小于设定数量的通告报文 时， 确认有效时钟源设备为稳定时钟源设备。 通过稳定性判定， 进一步判 断有效时钟源设备通告报文的收发是否稳定， 是否是可靠的时钟源。
沿用图 1 所示的示例， 时钟从设备进一步判断在设定的接收周期内是 否从时钟源设备 1接收到了设定数量的通告报文， 比如 4个通告报文发送 周期内， 接收到 2个通告报文， 则认为时钟源设备是稳定时钟源设备。 假 设时钟从设备从时钟源设备 1接收到了不小于设定数量的通告报文， 比如 接收到了 3个通告报文， 大于设定的数量 2, 则认为时钟源设备 1为稳定的 有效时钟源设备。
步驟 106: 不将有效时钟源设备加入备选时钟源设备列表中， 结束当前 流程。
当有效时钟源设备的稳定性判定失败， 确定出有效时钟源设备不是稳 定时钟源设备， 则可以将其从备选时钟源设备列表中排除， 不再供时钟从 设备切换时钟源时选择使用。
沿用图 1所示的示例，对于时钟源设备 2, 虽然时钟从设备也接收到了 其发送的通告报文， 但由于未接收到其反馈的检测反馈报文， 因此， 不将 其作为有效时钟源设备， 不进行稳定性判定， 也不将时钟源设备 2加入备 选时钟源设备列表中。
步驟 107: 将确定出的有效时钟源设备加入备选时钟源设备列表中。 时钟从设备判断出在设定的接收周期内从有效时钟源设备接收到了不 小于设定数量的通告报文时， 确认有效时钟源设备为稳定时钟源设备， 然 后根据设定的优先级算法确定有效时钟源设备的优先级， 并按照优先级顺 序将有效时钟源设备加入备选时钟源设备列表中。 当确定出有效时钟源设 备是稳定时钟源设备， 即是一个可靠的时间源时， 则可以将其作为备选时 钟源设备， 供时钟从设备切换时钟源时选择使用。
沿用图 1所示的示例，采用 BMC确定有效时钟源设备一一时钟源设备 1的优先级， 并按照优先级顺序将其加入备选时钟源设备列表中。
步驟 108: 时钟从设备需要切换时钟源设备时，从备选时钟源设备列表 中选择。
时钟从设备需要选择时钟源设备切换时， 则可以从备选时钟源设备列 表中按照优先级选择优先级最高的一个时钟源设备来进行切换。
此时， 备选时钟源设备列表中的时钟源设备均为上行和下行链路均正 常的时钟源设备， 从而不会选择到上行链路不通、 无法正常连接的时钟源 设备。
使用上述方法， 当时钟从设备和时钟源设备 1之间的链路上行和下行 双通， 而时钟从设备和时钟源设备 2之间的链路下行单通时， 则时钟从设 备由于不能接收到时钟源设备 2的检测反馈报文， 因此， 不会选择时钟源 设备 2。 若当前时钟从设备使用的时钟源是时钟源设备 2, 则时钟从设备会 选择切换的时钟源设备 1作为时钟源。 若当前时钟从设备使用的时钟源是 时钟源设备 1 , 则不会发生切换， 即便根据稳定性和 BMC确定时钟源设备 优先级确定时钟源设备 2的优先级高， 时钟从设备也不会选择切换到时钟 源设备 2作为时钟源 , 因为此时时钟源设备 2链路单通， 会导致时钟从设 备无法与该时钟源同步。
基于本发明实施例提供的上述时钟源设备切换选择方法， 本发明实施 例还提供一种时钟源设备切换选择系统， 该系统的结构参见图 1 所示， 包 括： 时钟从设备和时钟源设备。 其中时钟从设备和时钟源设备根据需要均 可以设置多个。
时钟从设备， 用于接收到时钟源设备发送的通告报文时， 向时钟源设 备发送链路检测报文； 接收到时钟源设备根据链路检测报文反馈的检测反 馈报文时， 确认该时钟源设备为有效时钟源设备； 以及确认有效时钟源设 备为稳定时钟源设备时， 将有效时钟源设备加入备选时钟源设备列表中； 当需要切换时钟源设备时， 从备选时钟源设备列表中选择。
时钟源设备， 用于接收到时钟从设备发送的链路检测报文时， 向时钟 从设备发送检测反馈报文。
优选的， 上述时钟从设备具体用于： 首次接收到时钟源设备发送的通 告报文时， 开始按照设定的检测周期以单播或组播的方式向时钟源设备发 送链路检测报文 , 发送的链路检测报文中携带时钟从设备的地址信息和时 钟源设备的地址信息。
优选的， 上述时钟源设备具体用于： 接收到时钟从设备发送的链路检 测报文， 根据链路检测报文中携带的时钟源设备的地址信息确定是发送给 自己的链路检测报文时， 向链路检测报文中携带的时钟从设备的地址信息 对应的时钟从设备发送检测反馈报文， 发送的检测反馈报文中携带时钟从 设备的地址信息和时钟源设备的地址信息。
相应的， 上述时钟从设备具体用于： 接收到检测反馈报文， 且其携带 的时钟从设备的地址信息、 时钟源设备的地址信息与自身发送的链路检测 报文中的时钟从设备的地址信息、 时钟源设备的地址信息相匹配时， 确定 该时钟源设备为有效时钟源设备。
优选的， 上述时钟从设备， 具体用于： 判断出在设定的接收周期内从 有效时钟源设备接收到了不小于设定数量的通告报文时， 确认该有效时钟 源设备为稳定时钟源设备； 根据设定的优先级算法确定该有效时钟源设备 的优先级， 并按照优先级顺序将有效时钟源设备加入备选时钟源设备列表 基于本发明实施例提供的上述时钟源设备切换选择系统， 本发明实施 例还提供一种时钟设备， 该设备可以作为时钟从设备使用， 也可以作为时 钟主设备使用， 其结构参见图 3所示。
当图 3所示的时钟设备作为时钟从设备使用时， 包括： 接收模块 10、 发送模块 20、 确定模块 30和选择模块 40。 其中，
接收模块 10, 用于接收时钟源设备发送的通告报文和接收时钟源设备 根据链路检测报文反馈的检测反馈报文。
发送模块 20, 用于接收到所述通告报文时， 向时钟源设备发送链路检 测报文。
确定模块 30, 用于接收到检测反馈报文时， 确认该时钟源设备为有效 时钟源设备； 以及确认所述有效时钟源设备为稳定时钟源设备时， 将有效 时钟源设备加入备选时钟源设备列表中。
选择模块 40, 用于当需要切换时钟源设备时， 从备选时钟源设备列表 中选择。
优选的， 上述发送模块 20, 具体用于： 接收模块 10首次接收到时钟源 设备发送的通告报文时， 开始按照设定的检测周期以单播或组播的方式向 时钟源设备发送链路检测报文， 发送的链路检测报文中携带时钟从设备的 地址信息和时钟源设备的地址信息。
优选的， 上述确定模块 30, 具体包括： 第一确定模块 301、 第二确定 模块 302和列表更新模块 303。
第一确定单元 301 , 用于接收到检测反馈报文， 且其携带的时钟从设备 的地址信息、 时钟源设备的地址信息与发送的链路检测报文中的时钟从设 备的地址信息、 时钟源设备的地址信息相匹配时， 确定该时钟源设备为有 效时钟源设备。
第二确定单元 302,用于判断出在设定的接收周期内从有效时钟源设备 接收到了不小于设定数量的通告报文时， 确认有效时钟源设备为稳定时钟 源设备。
列表更新单元 303 ,用于当第二确定单元 302确定有效时钟源设备为稳 定时钟源设备时， 根据设定的优先级算法确定所述有效时钟源设备的优先 当上述图 3所示的时钟设备作为时钟源设备使用时， 包括接收模块 10 和发送模块 20。 其中：
接收模块 10, 用于接收时钟从设备发送的检测反馈报文。
发送模块 20, 用于向时钟从设备发送通告报文， 以及接收模块 10接收 到时钟从设备发送的链路检测报文时， 向时钟从设备发送检测反馈报文。 具体用于当接收模块 10接收到时钟从设备发送的链路检测报文， 根据链路 检测报文中携带的时钟源设备的地址信息确定是发送给所在时钟源设备的 链路检测报文时， 向链路检测报文中携带的时钟从设备的地址信息对应的 时钟从设备发送检测反馈报文， 发送的检测反馈报文中携带时钟从设备的 地址信息和时钟源设备的地址信息。
本发明实施例提供的上述时钟源设备切换选择方法、 系统及装置， 时 钟从设备接收到时钟源设备的通告报文时， 会向其发起链路检测报文， 检 测上行链路是否正常。 当根据时钟源设备返回的检测反馈报文确定上行链 路通信正常时， 才会将该时钟源设备作为有效时钟源设备， 再进一步判定 其稳定后， 作为备选时钟源设备供切换时选择使用。 如果不能正确接收到 时钟源设备返回的检测反馈报文， 则可以知道上行链路不通， 不能使用该 时钟源设备作为时钟源。 通过链路检测反馈机制， 采用握手的方式， 确保 时钟源设备和时钟从设备之间的上下行链路双向正常， 避免了选择到链路 不通的时钟源设备， 影响时钟从设备时钟同步的正常进行。
且由于这种检测并不需要较高的频率， 因此不会给网络带宽带来较多 的额外开销， 以极少的资源开销即可确保网络出现单通等异常情况的时候 时钟从设备能够正确的选择主设备或者进行其他同步方式选择， 而不会直 接造成时间源选择的错误， 保证时钟从设备时钟同步的正确。
上述说明示出并描述了本发明的一个优选实施例， 但如前所述， 应当 理解本发明并非局限于本文所披露的形式， 不应看作是对其他实施例的排 除， 而可用于各种其他组合、 修改和环境， 并能够在本文所述发明构想范 围内， 通过上述教导或相关领域的技术或知识进行改动。 而本领域人员所 进行的改动和变化不脱离本发明的精神和范围， 则都应在本发明所附权利 要求的保护范围内。

Claims

权利要求书
1、 一种时钟源设备切换选择方法， 其特征在于， 包括：
时钟从设备接收到时钟源设备发送的通告报文时， 向时钟源设备发送 链路检测报文；
时钟从设备接收到时钟源设备根据所述链路检测报文反馈的检测反馈 报文时， 确认该时钟源设备为有效时钟源设备；
时钟从设备确认所述有效时钟源设备为稳定时钟源设备时， 将所述有 效时钟源设备加入备选时钟源设备列表中；
时钟从设备需要切换时钟源设备时， 从备选时钟源设备列表中选择。
2、 如权利要求 1所述的方法， 其特征在于， 所述时钟从设备接收到时 钟源设备发送的通告报文时， 向时钟源设备发送链路检测报文， 具体包括： 所述时钟从设备首次接收到时钟源设备发送的通告报文时， 按照设定 的检测周期以单播或组播的方式向时钟源设备发送链路检测报文； 所述链 路检测报文中携带时钟从设备的地址信息和时钟源设备的地址信息。
3、 如权利要求 1所述的方法， 其特征在于， 所述时钟从设备接收到时 钟源设备根据所述链路检测报文反馈的检测反馈报文时， 确认该时钟源设 备为有效时钟源设备， 具体包括：
时钟源设备接收到时钟从设备发送的链路检测报文， 根据链路检测报 文中携带的时钟源设备的地址信息确定是发送给自己的链路检测报文时， 向链路检测报文中携带的时钟从设备地址信息对应的时钟从设备发送检测 反馈报文； 所述检测反馈报文中携带时钟从设备的地址信息和时钟源设备 的地址信息；
所述时钟从设备接收到检测反馈报文， 且其携带的时钟从设备的地址 信息、 时钟源设备的地址信息与自身发送的链路检测报文中的时钟从设备 的地址信息、 时钟源设备的地址信息相匹配时， 确定该时钟源设备为有效 时钟源设备。
4、 如权利要求 1所述的方法， 其特征在于， 所述时钟从设备确认所述 有效时钟源设备为稳定时钟源设备时， 将所述有效时钟源设备加入备选时 钟源设备列表中， 具体包括：
时钟从设备判断出在设定的接收周期内从所述有效时钟源设备接收到 了不小于设定数量的通告报文时， 确认所述有效时钟源设备为稳定时钟源 设备；
根据设定的优先级算法确定所述有效时钟源设备的优先级， 并按照优
5、 如权利要求 1至 4任一所述的方法， 其特征在于， 所述时钟源设备 为使用精确时钟同步协议的时钟源设备； 所述从设备为使用精确时钟同步 协议的时钟从设备。
6、 一种时钟设备， 其特征在于， 包括： 接收模块、 发送模块、 确定模 块和选择模块；
所述接收模块， 用于接收时钟源设备发送的通告报文和接收时钟源设 备根据链路检测报文反馈的检测反馈报文；
发送模块， 用于接收到所述通告报文时， 向时钟源设备发送所述链路 检测报文；
确定模块， 用于接收到所述检测反馈报文时， 确认该时钟源设备为有 效时钟源设备； 以及确认所述有效时钟源设备为稳定时钟源设备时， 将所 述有效时钟源设备加入备选时钟源设备列表中；
选择模块， 用于当需要切换时钟源设备时， 从备选时钟源设备列表中 选择。
7、 如权利要求 6所述的时钟设备， 其特征在于， 所述发送模块， 具体 用于： 所述接收模块首次接收到时钟源设备发送的通告报文时， 按照设定的 检测周期以单播或组播的方式向时钟源设备发送链路检测报文； 所述链路 检测报文中携带时钟从设备的地址信息和时钟源设备的地址信息。
8、 如权利要求 6或 7所述的时钟设备， 其特征在于， 所述确定模块， 具体包括：
第一确定单元， 用于接收到检测反馈报文， 且其携带的时钟从设备的 地址信息、 时钟源设备的地址信息与自身发送的链路检测报文中的时钟从 设备的地址信息、 时钟源设备的地址信息相匹配时， 确定该时钟源设备为 有效时钟源设备；
第二确定单元， 用于判断出在设定的接收周期内从所述有效时钟源设 备接收到了不小于设定数量的通告报文时， 确认所述有效时钟源设备为稳 定时钟源设备；
列表更新单元， 用于当第二确定单元确定有效时钟源设备为稳定时钟 源设备时， 根据设定的优先级算法确定所述有效时钟源设备的优先级， 并 按照优先级顺序将所述有效时钟源设备加入备选时钟源设备列表中。
9、 一种时钟源设备切换选择系统， 其特征在于， 包括： 时钟从设备和 时钟源设备；
所述时钟从设备， 用于接收到时钟源设备发送的通告报文时， 向时钟 源设备发送链路检测报文； 接收到时钟源设备根据所述链路检测报文反馈 的检测反馈报文时， 确认该时钟源设备为有效时钟源设备； 以及确认所述 有效时钟源设备为稳定时钟源设备时， 将所述有效时钟源设备加入备选时 钟源设备列表中； 当需要切换时钟源设备时， 从备选时钟源设备列表中选 择；
所述时钟源设备， 用于接收到所述时钟从设备发送的链路检测报文时 , 向所述时钟从设备发送检测反馈报文。
10、 如权利要求 9所述的系统， 其特征在于， 所述时钟从设备， 具体 用于：
首次接收到时钟源设备发送的通告报文时， 按照设定的检测周期以单 播或组播的方式向时钟源设备发送链路检测报文； 所述链路检测报文中携 带时钟从设备的地址信息和时钟源设备的地址信息。
11、 如权利要求 9所述的系统， 其特征在于，
所述时钟源设备， 具体用于： 接收到时钟从设备发送的链路检测报文， 根据链路检测报文中携带的时钟源设备的地址信息确定是发送给自己的链 路检测报文时， 向链路检测报文中携带的时钟从设备地址信息对应的时钟 从设备发送检测反馈报文； 所述检测反馈报文中携带时钟从设备的地址信 息和时钟源设备的地址信息； 相应的，
所述时钟从设备， 具体用于： 接收到检测反馈报文， 且其携带的时钟 从设备的地址信息、 时钟源设备的地址信息与自身发送的链路检测报文中 的时钟从设备的地址信息、 时钟源设备的地址信息相匹配时， 确定该时钟 源设备为有效时钟源设备。
12、 如权利要求 9至 11任一所述的系统， 其特征在于， 所述时钟从设 备， 具体用于：
判断出在设定的接收周期内从所述有效时钟源设备接收到了不小于设 定数量的通告报文时， 确认所述有效时钟源设备为稳定时钟源设备；
根据设定的优先级算法确定所述有效时钟源设备的优先级， 并按照优
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