WO2011072442A1 - Procédé et système de communication entre horloge maître et horloge esclave - Google Patents

Procédé et système de communication entre horloge maître et horloge esclave Download PDF

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Publication number
WO2011072442A1
WO2011072442A1 PCT/CN2009/075639 CN2009075639W WO2011072442A1 WO 2011072442 A1 WO2011072442 A1 WO 2011072442A1 CN 2009075639 W CN2009075639 W CN 2009075639W WO 2011072442 A1 WO2011072442 A1 WO 2011072442A1
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WIPO (PCT)
Prior art keywords
clock
message
master
slave
slave clock
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PCT/CN2009/075639
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English (en)
Chinese (zh)
Inventor
曹海萍
陈伟
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中兴通讯股份有限公司
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Priority to PCT/CN2009/075639 priority Critical patent/WO2011072442A1/fr
Publication of WO2011072442A1 publication Critical patent/WO2011072442A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/14—Monitoring arrangements
    • 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 network time synchronization technologies, and in particular, to a method and system for master-slave clock communication. Background technique
  • the IEEE1588 PTP (Precision Time Protocol) protocol gives the master-slave clock to establish a link and synchronize the mechanism. From the clock side, it can be divided into two phases. The first is to select the master clock to establish the link phase, and then the selected During the synchronization phase of the master clock, all messages in the protocol can be collectively referred to as PTP messages. The following description will be made with reference to Fig. 1.
  • the announcement (Announce) message, the synchronization message (Sync), the follow-up message (FollowUp), and the sending time of the synchronization message in the follow-up message are periodically sent in a multicast manner.
  • the notification message is always monitored. After receiving the notification message, determine the clock quality indicator carried in the message. If the clock quality is better than the clock quality, select the clock. For your own master clock.
  • Synchronization with the selected master clock After the master clock is selected from the clock, the synchronization message sent by the selected master clock in multicast mode is received, the message is followed, and the selected master clock is received immediately after receiving the synchronization message. Sending a delay measurement message (Delay-Req), recording the transmission time, the main clock must reply to the delay response message (Delay-Resp) after receiving the delay measurement message, and the message carries the time of receiving the delay measurement message, so that A synchronization message interaction is completed.
  • the slave clock can know four timestamps at this time, tl: Sync message transmission time, t2: Sync message reception time, t3: Delay-Req message transmission time, t4: Delay-Req message reception time. . These time stamps are used to determine the time offset between this slave clock and the master clock, and local clock correction is performed to synchronize with the master clock.
  • the Announce message is periodically sent in multicast mode.
  • the notification message is always monitored.
  • the master clock is received.
  • the clock quality is better than its own clock quality, and the clock is chosen as its own master clock. This method leads to wasted bandwidth.
  • the slave clock is likely to frequently change its master clock and find a master clock that the user cannot recognize. Synchronization that causes master-slave cannot be effectively managed.
  • the communication mechanism given by the current protocol is that as long as the notification message and the synchronization message of the master clock can be received, the delay measurement message can be sent to the master clock, and the master clock receives the delay request from the slave clock (Delay-Req). For the message, the delay response (Delay-Resp) must be replied.
  • the delay response message sent by the master clock is sent at a relatively high frequency, so the wasted bandwidth and network resources cannot be ignored.
  • the security of the primary clock is a potential serious problem. For example, multiple slave clocks in the network maliciously send many delay measurement request messages, and the master clock must respond to all these messages, causing the master clock to bear. Summary of the invention
  • the technical problem to be solved by the present invention is to provide a method and system for master-slave clock communication, which realizes discriminating the validity of the slave clock, saves bandwidth resources, and improves manageability and security of the master clock and the slave clock.
  • the present invention provides a method for master-slave clock communication, which includes: a server authenticating a slave clock, determining that the slave clock is legal, and determining a master clock for the slave clock, the master The clock is time synchronized with the slave clock.
  • the slave clock sends a request message for querying the master clock to the server, and after the server receives the request message, the slave server authenticates the slave clock, determines that the slave clock is legal, and determines the master clock for the slave clock, The request message is forwarded to the master clock, and the master clock sends an inquiry master clock request response message to the slave clock, and the slave clock performs unicast negotiation with the master clock. After the negotiation succeeds, the master clock and the master clock The slave clock is time synchronized.
  • the request message for querying the master clock sent from the clock to the server includes a query for whether the master clock supports multiple types of message unicast negotiation; the master clock supports multiple types of message lists.
  • the Query Master Clock Request Response message sent to the slave clock carries an indication that supports multiple types of message unicast negotiation, and the master clock sends the notification message in a unicast manner after the negotiation succeeds. Synchronize messages and follow up messages.
  • the process of performing unicast negotiation between the slave clock and the master clock is: sending, by the slave clock, a unified unicast negotiation request message to the master clock, requesting the master clock to send the notification message, the synchronization message, and the follow-up in a unicast manner
  • the primary clock sends a unified unicast negotiation grant message to indicate that the negotiation is successful, and notifies the period in which the message is sent in unicast mode.
  • the server selects one of the master clocks including the slave clock as the master clock of the slave clock in the service range.
  • the server determines whether the slave clock is legal according to the IP address of the slave clock.
  • the slave clock After the server authenticates the slave clock, the slave clock is notified that the master clock fails to be queried.
  • the present invention further provides a system for master-slave clock communication, including: a master clock, a slave clock, and a server, wherein the server is configured to authenticate a slave clock, and determine that the slave clock is legal.
  • a master clock is determined for the slave clock; the master clock is used for time synchronization with the slave clock.
  • the slave clock is configured to send a request message for querying a master clock to the server, where the request message includes a query that the master clock supports multiple types of message unicast negotiation; the master clock is used to The slave clock sends an inquiry master clock request response message, and carries an indication of whether to support multiple types of message unicast negotiation; and after the negotiation with the slave clock succeeds, the notification message and the synchronization message are sent in a unicast manner.
  • the server is further configured to: after receiving the request message, authenticating the slave clock, determining that the slave clock is legal, and determining the master clock for the slave clock, forwarding the request message to The master clock. Further, the above system also has the following features:
  • the server is further configured to: select, as a master clock of the slave clock, one of the master clocks including the slave clock as a master clock of the slave clock; and further, determine, according to the IP address of the slave clock, the Whether the slave clock is legal.
  • the invention introduces the server as the slave clock authentication, determines that the slave clock is legal, and determines a master clock for the slave clock, and the slave clock synchronizes time with the master clock, thereby saving network resources and preventing the slave clock from frequently changing the master clock. Addresses the problem of the master clock providing a clock message to an undesired slave clock. During the time synchronization between the clock and the master clock, the master clock completes the notification message, the synchronization message, and the unicast request of the delay measurement response message by one unicast negotiation, which can further improve the effectiveness of the unicast negotiation.
  • the server selects one of the master clocks that are the best clock quality from the master clocks of the clock as the master clock of the slave clock to solve the problem that the master clock sends synchronous messages to the slave clocks that are not within the authorized range, thereby wasting bandwidth resources.
  • FIG. 1 is a schematic diagram of a master-slave clock establishing link process in an existing protocol
  • the system of master-slave clock communication includes: master clock, slave clock, and server.
  • the master clock is used for time synchronization with the slave clock. It is also used to carry multiple types of message unicast in the query sending master clock request response message to the slave clock when supporting multiple types of message unicast negotiation. An indication of negotiation; and after successfully negotiating with the slave clock, sending a notification message, a synchronization message, and a follow-up message in a unicast manner.
  • the slave clock is configured to send a request message for querying the master clock to the server, where the request message includes a query for whether the master clock supports multiple types of message unicast negotiation, and is further configured to: after receiving the notification message, determine that the master clock is Its own master clock, and the time synchronization with the master clock is completed according to the synchronization message and the follow-up message.
  • a server after receiving the request message, authenticating the slave clock, determining that the slave clock is legal, determining a master clock for the slave clock, and forwarding the request message to the master clock; And selecting, as the master clock of the slave clock, one of the master clocks including the slave clock in the service range; and determining whether the slave clock is legal according to the IP address of the slave clock.
  • the method for master-slave clock communication includes: the server authenticates the slave clock, determines that the slave clock is legal, and determines a master clock for the slave clock, and the master clock is time-synchronized with the slave clock.
  • the method for master-slave clock communication specifically includes:
  • Step 201 After the clock is powered on (Power On), send a request message (Req_Master) for querying the master clock to the server and start timing.
  • the request message may include: query of the master clock information, whether the master clock supports unicast negotiation.
  • the query can be one of the following parameters: Whether the primary clock supports a single type of message unicast negotiation (that is, unicast negotiation for each type of message, after the primary clock receives a unicast negotiation request for a certain type of message, The type of the message is sent by the unicast message.
  • the master clock supports multiple types of message unicast negotiation. After receiving the unicast negotiation message, the master clock sends unicast messages to multiple types of messages. Two or three messages in the synchronization message and the follow-up message are unicast).
  • This request message may also include a query of whether the master clock is locked with the grandmother's clock (the grandmother's clock is generally a global positioning clock, and the final purpose of synchronizing the clock from the master clock is to achieve synchronization with the global positioning clock.
  • the master clock is not synchronized with the grandmother's clock. When the clock it provides is unstable, it affects the accuracy of the slave clock).
  • the message body format of the request message (Req_Master) for querying the master clock is as shown in Table 1:
  • the tlvType field may use the reserved value of the TLV TYPE in the current protocol, and is used to indicate that the current TLV is a message for querying the master clock during access;
  • the lengthField field indicates the total length of the message body, ie MessageType, Externd-messageType, and Reserved fields, in Bytes.
  • the Externd-messageType field is only used for extended messages and can generally not be used.
  • the unicastNegotiationEnable field indicates whether the traditional unicast negotiation is supported, that is, the negotiation mode given by IEEE1588. If a certain type of message is desired to be unicast, the message is unicast once. If there is a type N message that wants to be unicast, the unicast negotiation is performed. N times.
  • the unicastNegotiationUniform field indicates whether a unicast request for unicast negotiation is completed to complete the unicast request for the Annouce, Sync, and Delay-Resp messages.
  • the transportSpecific field indicates the transport protocol number used by the IEEE1588 PTP message. For example, if the PTP message transmission uses UDP, this field is the number of the UDP protocol.
  • the messageType field indicates the specific type of the PTP message. For example, if a notification message is sent, this field specifies that the message types in the VTP version of the PTP protocol are: a synchronization message, a delay measurement request message, a delay measurement response message, a notification message, Follow-up messages, signaling messages, management messages, peer-to-peer delay measurement request messages, peer-to-peer delay measurement messages, peer-to-peer follow-up messages. In addition to signaling messages and management messages, these messages refer to a single message, and signaling messages and management messages are collectively referred to as two types of messages. For example, when the message type in the message header is a signaling message, the sub-message type of the signaling message needs to be specified, and the management message is similar. But when the message type in the message header is a notification message, it is the notification message.
  • the versionPTP field indicates the PTP protocol version number.
  • the messageLength field indicates the length of the entire PTP message, starting from the first byte of the PTP header to the end of the last byte of the message body.
  • the correctionField field indicates the dwell time of the message in the transparent clock, and only the field used for synchronization needs to fill in this field.
  • the logMessagelnterval field indicates the logarithm of the message transmission period.
  • the message type field shall indicate a signaling message, i.e., the field is set to (3).
  • the message body format for notifying the slave clock to query the master clock can be as shown in Table 3:
  • the tlvType field can use the reserved value of the TLV TYPE in the current protocol, which is the same as the message usage value of the query master clock message.
  • the messageType field indicates that the current message is the query master clock failure message
  • the accesstReq field Indicates whether it is allowed to synchronize with the master clock managed by this server.
  • the Externd-messageType field is only used for extended messages and can generally not be used.
  • the accesstReq field indicates whether the requesting master clock failed or succeeded.
  • Step 204 The server determines a master clock for the slave clock, and forwards the received request message to the j3 ⁇ 4 master clock.
  • the server selects one of the master clocks of the slave clock to be the master clock of the slave clock in the service range.
  • Step 205 The master clock establishes a query master clock request response message, and in the request response message, it can indicate whether the unicast negotiation is supported, whether multiple types of message unicast are supported, and whether the message body format of the ancestor request response message can be As shown in Table 4:
  • the tlvType field can use the reserved value of the TLV TYPE in the current protocol, which is the same as the message usage value of the query master clock message.
  • the lengthField field indicates that the message body is also messageType, Externd-messageType, The total length of the unicastNegotiationEnable, unicastNegotiationUniform, and Reserved fields, in Bytes.
  • the messageType field indicates that the current message is a response to the query master clock message.
  • the Externd-messageType field is only used for extended messages and can generally not be used.
  • the unicastNegotiationEnable field indicates whether unicast negotiation is supported.
  • unicastNegotiationUniform supports a unicast negotiation to complete unicast requests for all messages.
  • Step 206 When the slave clock learns that the master clock supports multiple types of message unicast negotiation (that is, the unicastNegotiationUniform is 1), the slave clock initiates a multi-type message unicast negotiation to the master clock, that is, sends a unified unicast negotiation request message.
  • the request master clock sends notification messages, synchronization messages, and follow-up messages in unicast mode.
  • the tlvType field can use the reserved value of the TLV TYPE in the current protocol, which is the same as the message usage value of the query master clock message.
  • the lengthField field represents the message body, which is the total length of the messageType, reseved, loglnterAnnounceMessagePeriod, loglnterSyncMessagePeriod, loglnterDelayRespMessagePeriod, and durationField fields. Bit.
  • the message Type field indicates that the currently requested unicast message is Announce, Sync, and Delay-Res messages.
  • the value of the reserved value of the message field in the current IEEE1588 protocol can be used. That is to say, F is used to announce unicast for Announce, Sync, Delay-Res.
  • a logInterAnnounceMessagePeriod (where eight represents an exponential operation) sends a notification message for the period.
  • the loglnterSyncMessagePeriod field indicates that the current negotiation request master clock sends a synchronization message with a period of 2 A logInterSyncMessagePeriod.
  • the loglnterDelay espMessagePeriod field indicates that the current negotiation request master clock sends a delayed request response message with a period of 2 A logInterDelay espMessagePenod.
  • the durationField field indicates the expected duration of the request for the main clock cycle to send three types of messages, and the field is filled with 0 to indicate an infinite time.
  • Step 207 After receiving the unified unicast negotiation request message described in step 206, the master clock sends a unified unicast negotiation grant message to indicate that the negotiation is successful, and notifies the period in which the message is sent in a unicast manner, and the message body format of the message is as follows: Table 6 shows:
  • the meaning of each field of the message is as follows:
  • the tlvType field corresponds to the field in Table 5.
  • the lengthField field corresponds to the field in Table 5.
  • the messageType field is the same as the field in Table 5.
  • the loglnterAnnounceMessagePeriod field indicates that the actual approved unicast notification message period is 2 A logInterAmounceMessagePeriod. That is, in the future, the Announce message is actually sent in this cycle;
  • the loglnterSyncMessagePeriod field indicates that the actual approved unicast synchronization message period is 2 A logInterSyncMessagePeriod. That is, the Sync message is actually sent in this cycle in the future;
  • the loglnterDelay espMessagePenod field indicates that the period of the actually approved unicast delay measurement response message is 2 A logInterSyncMessagePenod. That is, the Delay-Resp message is actually sent in this cycle;
  • the durationField field corresponds to the field in Table 5.
  • Step 208 When the primary clock supports the unicast mode, the notification message, the synchronization message, and the follow-up message are sent to the slave clock in the unicast mode in the period of step 207;
  • Step 209 After receiving the notification message from the clock, determine that the master clock is its own master clock, and complete synchronization with the master clock according to the synchronization message and the follow-up message.
  • the synchronization message is received from the clock, and the delay request message is set up and sent to the master clock in the unicast mode; the master clock receives the delay request message, immediately sends the delay response message, and puts the time of receiving the delay request message into the delayed response.
  • the slave clock uses the synchronization message reception time, the synchronization message transmission time and the delay request transmission time carried in the follow-up message, the delay measurement reception time carried in the delay response message, the calculation time deviation, and the local clock Correction, complete synchronization with the master clock.
  • the invention introduces the server as the slave clock authentication, determines that the slave clock is legal, and determines a master clock for the slave clock, and the slave clock synchronizes time with the master clock, thereby saving network resources and preventing the slave clock from frequently changing the master clock.
  • the master clock sends the message in unicast mode.
  • the server selects the best one of the clocks from the master clocks of the clock as the master clock of the slave clock, which can solve the problem that the slave clock cannot be selected to the user's desired master clock in the prior art, and the master clock pair is not authorized.
  • the issue of synchronous message transmission from the slave clock in the range wastes bandwidth resources.
  • the invention can realize the discrimination of the slave clock legality, save bandwidth resources, and improve the manageability and security of the master clock and the slave clock.

Abstract

La présente invention porte sur un procédé et un système de communication entre une horloge maître et une horloge esclave. Le procédé comprend les étapes suivantes : un serveur authentifie l'horloge esclave et détermine l'horloge maître pour l'horloge esclave après avoir jugé que l'horloge esclave était légale; l'horloge esclave réalise une synchronisation de temps avec l'horloge maître. L'invention introduit le serveur pour authentifier l'horloge esclave et pour déterminer l'horloge maître pour l'horloge escale après avoir jugé que l'horloge escale était légale et permet ensuite à l'horloge esclave de réaliser une synchronisation de temps avec l'horloge maître, de façon à économiser les ressources réseau, à empêcher l'horloge esclave de changer fréquemment d'horloge maître, et à résoudre le problème selon lequel l'horloge maître envoie simultanément un message d'horloge à une horloge esclave imprévue. Dans le processus de synchronisation de l'horloge esclave avec l'horloge maître, l'horloge maître réalise la requête d'envoi individuel du message d'annonce, du message de synchronisation et du message de réponse de mesure de retard par négociation d'envoi individuel, ainsi l'efficacité de la négociation d'envoi individuel peut être davantage améliorée.
PCT/CN2009/075639 2009-12-16 2009-12-16 Procédé et système de communication entre horloge maître et horloge esclave WO2011072442A1 (fr)

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CN102355346A (zh) * 2011-10-13 2012-02-15 中兴通讯股份有限公司 一种时钟同步源设备有效性判定方法及装置
CN106411446A (zh) * 2016-08-29 2017-02-15 烽火通信科技股份有限公司 一种在单播模式下实现1588时间同步的自适应方法
WO2022018727A1 (fr) * 2020-07-24 2022-01-27 Essence Security International (E.S.I.) Ltd. Synchronisation d'un dispositif pour l'authentification

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102355346A (zh) * 2011-10-13 2012-02-15 中兴通讯股份有限公司 一种时钟同步源设备有效性判定方法及装置
CN106411446A (zh) * 2016-08-29 2017-02-15 烽火通信科技股份有限公司 一种在单播模式下实现1588时间同步的自适应方法
CN106411446B (zh) * 2016-08-29 2018-08-31 烽火通信科技股份有限公司 一种在单播模式下实现1588时间同步的自适应方法
WO2022018727A1 (fr) * 2020-07-24 2022-01-27 Essence Security International (E.S.I.) Ltd. Synchronisation d'un dispositif pour l'authentification
GB2597506A (en) * 2020-07-24 2022-02-02 Essence Security International Esi Ltd Synchronisation of a device for authentication

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