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WO2011160595A1 - Procédé, noeud d'horloge esclave et système permettant de sélectionner un noeud d'horloge maître basé sur un protocole de précision temporelle (ptp) et sur une qualité de liaison - Google Patents

Procédé, noeud d'horloge esclave et système permettant de sélectionner un noeud d'horloge maître basé sur un protocole de précision temporelle (ptp) et sur une qualité de liaison Download PDF

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Publication number
WO2011160595A1
WO2011160595A1 PCT/CN2011/076233 CN2011076233W WO2011160595A1 WO 2011160595 A1 WO2011160595 A1 WO 2011160595A1 CN 2011076233 W CN2011076233 W CN 2011076233W WO 2011160595 A1 WO2011160595 A1 WO 2011160595A1
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WO
WIPO (PCT)
Prior art keywords
clock node
link
delay
value
master clock
Prior art date
Application number
PCT/CN2011/076233
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English (en)
Chinese (zh)
Inventor
常伟
廖俊锋
Original Assignee
中兴通讯股份有限公司
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Publication of WO2011160595A1 publication Critical patent/WO2011160595A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—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 mobile communications, and in particular, to a method, a slave clock node and a system for selecting a master clock node based on a precision clock synchronization protocol (TM) and link quality.
  • TM precision clock synchronization protocol
  • clock synchronization In the field of mobile network technology, there is a strict requirement for high-precision clock synchronization.
  • the purpose of clock synchronization is to synchronize the clocks of nodes in the network to the same reference.
  • Frequency Division Duplex such as Universal Mobile Telecommunications System (UMTS)
  • UMTS Universal Mobile Telecommunications System
  • TDD Time Division Duplexing
  • the wireless system such as Time Division-Synchronous Code Division Multiple Access (CDMA) or Code Division Multiple Access (CDMA) requires synchronization of the clock frequency and phase.
  • CDMA Time Division-Synchronous Code Division Multiple Access
  • CDMA Code Division Multiple Access
  • Clock synchronization through PTP protocol includes establishing master-slave hierarchy and clock synchronization Stages.
  • PTP first organizes the clock nodes in the network into the synchronization level of the master clock-Slave Clock.
  • the master clock node provides the standard clock, and the local time is released to the network at regular intervals.
  • the time information sent by the master clock node is received, and after the correlation calculation is performed, the time of the clock node is synchronized to the master clock node.
  • a slave clock node can connect multiple potential master clock nodes through a switch, for how to resolve multiple potential master clock nodes (such as n master clocks as shown in Figure 1)
  • Node, n is an integer greater than 1)
  • a master clock node is selected as its primary clock node for time synchronization.
  • the PTP protocol proposes the best master clock algorithm (BMC) to determine the master-slave relationship.
  • the BMC needs to complete the determining the master-slave relationship based on the announce message.
  • the announcement message has data describing the clock characteristics. The characteristics mainly include the clock quality of the master clock node (the clock level of the user-configured clock level and the clock accuracy, etc.). Does not involve link information).
  • the data set comparison algorithm in the BMC is used to compare the data set in the notification message received by all the ports, select one master clock node, and then use the state decision algorithm to determine each clock. Status (Master Or Slave).
  • the time synchronization is performed between the master clock node and the slave clock node through the interaction time packet.
  • Four types of messages are defined in the PTP protocol: Synchronous Message (Sync), Follow Message (Follow_up), Delay Request Message (Delay_req), and Delay Response Message (Delay-Resp).
  • the slave clock node uses the above four messages to obtain a time stamp to determine its time offset from the master clock node to adjust its own clock.
  • the timestamp includes a time t1 at which the master clock node sends the synchronization message, a time t2 when the synchronization message is received from the clock node, a time t3 when the delay message is sent from the clock node, and a delay request received by the master clock node.
  • the time t4 of the text, the time offset Offset between the master and slave clock nodes, and the network transmission link delay Delay are as follows: (1) and (2):
  • T2-tl Delay+Offset ( 1 )
  • T4-t3 Delay-Offset ( 2 )
  • the time deviation Offset [(t2-tl )-(t4-t3)]/2 is obtained, and the slave clock node can adjust its own time offset based on the calculated time offset Offset. clock.
  • the traditional private telephone network usually uses the BMC algorithm to select the primary clock node, receives the advertisement packets sent by multiple primary clock nodes from the clock node, and compares the advertisement packets, and selects one of the advertisement packets. The best master clock node.
  • the master clock node in the PTN does not send an advertisement "3 ⁇ 4 text, which causes the problem that the destination master clock node cannot be selected when facing multiple master clock nodes.
  • the prior art BMC algorithm cannot According to the user's needs, the master clock node cannot be selected according to the user's pre-defined selection strategy.
  • the main purpose of the present invention is to provide a method for selecting a master clock node based on PTP and link quality, a slave clock node and a system, and aiming to select a destination master clock node according to the quality of the link to solve the master clock in the traditional PTN.
  • the invention provides a method for selecting a master clock node based on PTP and link quality, and the method comprises the following steps:
  • the link quality selection policy is configured according to the link quality indicator, where the link quality indicator includes: link loss rate, and/or delay jitter, and/or link delay;
  • the link quality selection policy includes: a first strategy for selecting a destination master clock node by using a link loss rate as a first judgment indicator, and using a delay jitter and/or a link delay as a second judgment indicator; Or
  • the selecting a destination master clock node according to the configured link quality selection policy includes:
  • the value of the link loss ratio is obtained, or according to the value of the link loss ratio, or according to the link loss ratio and delay jitter and/or link delay. For the value of time, select the corresponding primary clock node as the destination primary clock node.
  • the selecting a destination master clock node according to the configured link quality selection policy includes:
  • the corresponding master clock node is selected as the destination master clock node.
  • the selecting a destination master clock node according to the configured link quality selection policy includes:
  • the master clock node And receiving, by the master clock node, the synchronization packet that is sent by the interval time and carries a first timestamp indicating a synchronization message sending time; Acquiring a second timestamp indicating the time of receiving the synchronization message; identifying, according to a clock identifier in the synchronization message, a primary clock node that sends the synchronization message, and saving related information of the primary clock node, and Counting the number of received synchronization packets plus one count into the number of received packets;
  • the value of the packet loss rate is calculated according to the number of received packets, and the value of the packet loss rate is a ratio of the number of received packets from the clock node to the theoretical expected value during the duration.
  • the method further includes:
  • the master clock node When the master clock node is a two-step clock, the number of received follow messages is counted in the number of received packets.
  • the present invention provides a slave clock node that selects a master clock node based on PTP and link quality, and the slave clock node includes:
  • a configuration module configured to configure a link quality selection policy according to a link quality indicator, where the link quality indicator includes: a link loss rate, and/or a delay jitter, and/or a link delay;
  • the selecting module is configured to select a destination primary clock node according to the configured link quality selection policy.
  • the link quality selection policy includes: a first strategy for selecting a destination master clock node by using a link loss rate as a first judgment indicator, and using a delay jitter and/or a link delay as a second judgment indicator; Or Taking the delay jitter as the first judgment indicator, and selecting the second strategy of the destination master clock node by using the link loss rate and/or the link delay as the second judgment indicator; or
  • the link loss rate and/or the delay jitter are used as the second judgment indicator to select the third strategy of the destination master clock node.
  • the selecting module comprises:
  • an obtaining unit configured to: when the first policy is used to select a destination primary clock node, obtain a link selection unit, configured to obtain a value of a link loss ratio obtained according to the acquiring unit, or a link loss rate according to a link, and For the value of delay jitter and/or link delay, select the corresponding master clock node as the destination master clock node.
  • the acquiring unit is further configured to: when the target primary clock node is selected by using the second policy, obtain a value of the delay jitter, or obtain a delay jitter, a link loss ratio, and/or a link delay.
  • Time value when the target primary clock node is selected by using the second policy, obtain a value of the delay jitter, or obtain a delay jitter, a link loss ratio, and/or a link delay.
  • the selecting unit is further configured to: according to the value of the delay jitter acquired by the acquiring unit, or the target master clock node.
  • the acquiring unit is further configured to: when selecting the destination primary clock node by using the third policy, obtain a link delay value, or obtain a link delay value and a link loss ratio and/or The value of the delay jitter;
  • the selecting unit is further configured to: according to the value of the link delay acquired by the acquiring unit, or the target master clock node.
  • the acquiring unit includes:
  • a sending subunit configured to send, to the primary clock node corresponding to the slave clock node, a management message or a signal message carrying an interval and duration of the synchronization message sent by the desired primary clock node
  • a receiving subunit configured to receive, by the primary clock node, the synchronization packet that is sent by the interval time and carries a first timestamp indicating a synchronization packet sending time
  • Obtaining a sub-unit configured to acquire a second timestamp indicating a time for receiving the synchronization packet; identifying a primary clock node that sends the synchronization packet according to a clock identifier in the synchronization packet, and saving related information of the primary clock node ;
  • a message counting sub-unit configured to count the number of received synchronization packets plus one count into the number of received messages
  • the sending subunit is further configured to send a delay request message to the primary clock node, where the acquiring subunit is further configured to acquire a third timestamp indicating a sending time of the delayed request message;
  • the receiving subunit is further configured to receive, by the primary clock node, a delayed response packet that includes a fourth timestamp indicating a time when the delay request packet is received;
  • a calculating subunit configured to calculate a value of the link delay according to the first timestamp, the second timestamp, the third timestamp, and the fourth timestamp;
  • the value of the packet loss rate is calculated according to the number of received packets, and the value of the packet loss rate is a ratio of the number of received packets from the clock node to the theoretical expected value in the duration.
  • the ⁇ gram count subunit is further configured to count the number of received follow messages into the number of received packets when the master clock node is a two-step clock.
  • the present invention proposes a system for selecting a master clock node based on PTP and link quality, comprising a slave clock node as described above, and a plurality of master clock nodes connected to the slave clock node through a switch.
  • the invention is based on the method of selecting the master clock node based on the PTP and the link quality, the slave clock node and the system, and configuring the link quality through the user (mainly including the link loss rate, and/or the delay jitter, and/or Or link delay and other indicators) select the policy and combine the policy according to the link quality selected by the user.
  • the PTP protocol selects the destination master clock node, which not only satisfies the user's actual selection requirements, but also improves the selectivity and flexibility when acquiring the master clock node, and solves the problem that the master clock node cannot select the master when the announcement message is not sent in the traditional PTN.
  • the problem with the clock node DRAWINGS
  • FIG. 1 is a schematic diagram of a connection between a master clock node and a slave clock node in an existing mobile network
  • FIG. 2 is a schematic diagram of time synchronization between a master clock node and a slave clock node through an interaction time message in the prior art
  • FIG. 3 is a schematic diagram of a method for selecting a master clock node based on PTP and link quality according to an embodiment of the present invention
  • step 102 is a schematic diagram of a specific process of step 102 in the method for selecting a master clock node based on PTP and link quality shown in FIG. 3;
  • FIG. 5 is a schematic flowchart of obtaining a value of a link loss rate, a delay jitter, and a link delay in a link quality indicator in the foregoing embodiment
  • FIG. 6 is a schematic flow chart of another embodiment of a method for selecting a master clock node based on PTP and link quality according to the present invention.
  • FIG. 7 is a schematic flow chart of still another embodiment of a method for selecting a master clock node based on PTP and link quality according to the present invention.
  • FIG. 8 is a schematic structural diagram of a configuration of a slave clock node according to an embodiment of the present invention for selecting a master clock node based on PTP and link quality;
  • FIG. 9 is a schematic structural diagram of a selection module of a slave clock node selected from a master clock node based on PTP and link quality shown in FIG. 8;
  • FIG. 10 is a schematic diagram showing the structure of a component selected by a module in a slave clock node based on PTP and a link quality selection master clock node shown in FIG. 9;
  • FIG. 10 is a schematic diagram showing the structure of a component selected by a module in a slave clock node based on PTP and a link quality selection master clock node shown in FIG. 9;
  • FIG. 11 is a schematic diagram of a system for selecting a master clock node based on PTP and link quality according to the present invention. Schematic diagram of the composition.
  • the solution of the embodiment of the present invention is as follows: Based on the link quality selection policy configured by the user, the main clock node is selected according to the quality of the link (including the link delay, jitter, or packet loss rate). To solve the problem that the primary clock node in the traditional PTN does not send the advertisement packet and cannot obtain the destination master clock node.
  • the link quality selection policy configured by the user uses the link loss rate as the judgment indicator of the destination master clock node and sets the primary clock node with the smallest link loss rate as the destination master clock node
  • the following method is adopted.
  • Obtaining the destination master clock node The slave clock node sends a management message or a signal message, requires interaction with multiple master clock nodes connected thereto, and then counts the received 1588 interaction packets of the multiple master clock nodes separately, in the predetermined
  • the time between the number of packets actually received and the number of packets expected to be received by the clock node are compared, and the packet loss ratio between the slave clock node and each master clock node is calculated, and one of the packets is selected.
  • the primary clock node with the lowest link loss rate is used as the destination primary clock node.
  • an embodiment of the present invention provides a method for selecting a primary clock node based on PTP and link quality, and the method includes:
  • Step 101 Configure a link quality selection policy according to the link quality indicator.
  • the link quality indicator includes: link loss rate, and/or delay jitter, and/or link delay.
  • the operating environment of the method embodiment includes a slave clock node and a plurality of (multiple) master clock nodes connected to the slave clock node through the switch, when an optimal master clock node, that is, a destination master clock node, needs to be selected for the slave clock node.
  • an optimal master clock node that is, a destination master clock node
  • the user can select the best master clock node according to the link quality. You can select one of the link quality indicators or Two or three to select the primary clock node. For example, the user can configure the link loss rate as the first judgment indicator, and use the delay jitter and/or the link delay as the second judgment indicator to select the target primary clock node.
  • the first strategy or using the delay jitter as the first judgment indicator, using the link loss rate and/or the link delay as the second judgment indicator to select the second strategy of the destination master clock node; or
  • the first determining indicator selects a third policy of the target primary clock node by using the link loss rate and/or the delay jitter as the second determining indicator.
  • the user can select the primary clock node with the lowest link loss rate as the destination primary clock node of the secondary clock node, and at the same time, the link loss rate is the first judgment indicator, with a delay.
  • the jitter and/or link delay is used to select the destination primary clock node for the second judgment indicator, that is, when there are multiple primary clock nodes with the smallest link loss rate, the delay jitter or the link delay may be the second.
  • the primary clock node with the lowest delay or the lowest link delay in the primary clock node with the lowest link loss rate is the primary clock node.
  • the user can pre-configure various indicators in the link quality as required.
  • the threshold is used to select the destination master clock node. For example, the packet loss rate can be less than 10%.
  • Step 102 Select a destination primary clock node according to the configured link quality selection policy.
  • the destination primary clock node is selected according to the configured link quality selection policy. For example, when the primary clock node is selected by using the first policy, the corresponding primary clock node may be selected as the primary clock node according to the minimum value of the link loss rate in the link quality indicator, where the link loss rate is the smallest.
  • the value can be obtained by sending a synchronization packet between the clock node and the primary clock node in the PTP protocol.
  • step 102 may include:
  • Step 1021 When the first primary node is selected by using the first policy, obtain the value of the link loss rate, or obtain the link loss rate, and the value of the delay jitter and/or the link delay.
  • Step 1022 Select a corresponding primary clock node as the destination primary clock node according to the value of the link loss ratio, or according to the link loss ratio and the value of the delay jitter and/or the link delay.
  • the destination primary clock node when the destination primary clock node is selected by using the first policy, the destination primary clock node may be selected according to the value of the link loss ratio, and the link loss rate may be the first judgment indicator. The delay jitter and/or the link delay are used to select the destination primary clock node for the second judgment indicator.
  • the value of the link loss rate is obtained to minimize The primary clock node corresponding to the link loss rate of the value is the destination primary clock node.
  • the delay jitter and/or the link delay are selected as the second judgment indicator.
  • the main clock node for example, there are multiple primary clock nodes with the smallest link loss rate. In this case, the delay jitter or the link delay is the smallest among the primary clock nodes with the smallest packet loss rate.
  • the primary clock node is the destination primary clock node.
  • the specific process of obtaining the value of the link loss rate, the value of the delay jitter, and the value of the link delay in the link quality indicator may include:
  • Step 501 The slave clock node sends a management message or a signal message carrying the interval and duration of the synchronization message sent by the desired master clock node to the corresponding master clock node.
  • Step 502 Receive a synchronization packet that carries the first timestamp sent by the primary clock node in the interval time.
  • the first timestamp is represented by tl, and the first timestamp is the time at which the synchronization packet is sent by the primary clock node.
  • Step 503 Obtain a second timestamp indicating the time of receiving the synchronization packet, identify a primary clock node that sends the synchronization packet according to a clock identifier in the synchronization packet, and perform related information of the primary clock node. Save, and count the number of received synchronization packets plus one count into the number of received messages;
  • the second timestamp is represented by t2, indicating the time when the synchronization message is received from the clock node.
  • Step 504 Send a delay request message to the primary clock node, and obtain a third timestamp indicating a time for sending the delay request message.
  • the third timestamp is represented by t3, indicating the time when the delay request is sent from the clock node.
  • Step 505 When the receiving the primary clock node sends the message indicating that the delay request message is received Delayed response message of the fourth timestamp between;
  • the fourth timestamp is represented by t4, indicating the time when the master clock node receives the delay request message.
  • Step 506 Calculate a value of the link delay according to the first timestamp, the second timestamp, the third timestamp, and the fourth timestamp.
  • the average value of the delay of each link delay is taken as the link delay of the current primary clock node.
  • Step 507 Calculate a value of the delay jitter according to the first timestamp, the second timestamp, the third timestamp, and the fourth timestamp.
  • the difference between the maximum value and the minimum value of the delay value of each link delay is the value of the delay jitter, and the value of the delay jitter is used as the delay of the current master clock node.
  • the value of the jitter is selected, when the destination clock node is selected by using the delay jitter as the index, the master clock node with the smallest delay jitter value is selected as the destination master clock node.
  • Step 508 After expiration of the duration, calculate a value of a packet loss rate according to the number of received packets, where the value of the packet loss rate is a ratio of the number of received packets from the clock node to the theoretical expected value in the duration.
  • the link loss may be obtained through the foregoing steps 501 to 503 and step 508.
  • the delay jitter and/or the link delay are selected as the second judgment index.
  • the value of the link delay is selected from the primary clock node with the smallest link loss rate of the corresponding link selected in the duration, and the corresponding primary clock node with the smallest delay jitter and/or the link delay is selected.
  • the node serves as the destination master clock node, so as to achieve the purpose of selecting the destination master clock node according to the configured link quality selection policy.
  • a user selects a link quality (including a link loss rate, a delay jitter, or a link delay) to select a policy, and selects a destination master clock according to a link quality selection policy configured by the user and a PTP protocol.
  • the node not only satisfies the actual selection requirements of the user, but also improves the multi-selectivity and flexibility when acquiring the master clock node, and solves the problem that the master clock node cannot transmit the advertisement message when the master clock node does not send the advertisement message.
  • step 102 specifically includes:
  • Step 1023 When the second policy is used to select the destination primary clock node, the step 1024 of acquiring the delay jitter is performed according to the value of the delay jitter, or according to the delay jitter and the link loss rate and/or the link delay. Value, select the corresponding primary clock node as the destination primary clock node.
  • the destination primary clock node when the second policy is selected to select the target primary clock node, the destination primary clock node may be selected according to the value of the delay jitter, and the delay jitter may be used as the first judgment indicator, and the link loss rate and / or the link delay is the second judgment indicator to select the destination master clock node.
  • the value of the delay jitter can be obtained through the above steps 501 to 505 and step 507, and The primary clock node corresponding to the minimum delay jitter in the duration is identified, and the primary clock node is used as the destination primary clock node.
  • the delay jitter When the delay jitter is selected as the first judgment indicator, and the target primary clock node is selected by using the link loss ratio and/or the link delay as the second judgment indicator, the delay jitter can be obtained according to the foregoing steps 501 to 508.
  • Link loss rate and/or link delay The value of the primary clock node with the smallest link delay rate and/or the link delay is selected in the primary clock node with the smallest delay jitter selected in the duration, and the primary clock node is used as the primary clock. The node, so as to achieve the purpose of selecting the destination primary clock node according to the configured link quality selection policy.
  • step 102 may specifically include: Step 1025: When the third policy selects the destination primary clock node, step 1026 of obtaining the link delay is selected according to the value of the link delay or according to the link delay and the link loss rate and/or the value of the delay jitter.
  • the primary clock node is the destination primary clock node.
  • the destination primary clock node when the third policy is selected to select the destination primary clock node, the destination primary clock node may be selected according to the value of the link delay, and the link delay may be used as the first judgment indicator, and the link loss rate is And/or delay jitter is the second judgment indicator to select the destination master clock node.
  • the value of the link delay can be obtained through the foregoing steps 501 to 506. And identifying the primary clock node corresponding to the minimum link delay in the duration, and using the primary clock node as the destination primary clock node.
  • the link delay When the link delay is selected as the first judgment indicator, and the target primary clock node is selected by using the link loss ratio and/or the delay jitter as the second judgment indicator, the link delay may be obtained according to the foregoing steps 501 to 508. And the value of the link loss rate and/or the delay jitter, and the corresponding link loss rate and/or the delay jitter minimum is selected among the primary clock nodes with the smallest link delay selected in the duration.
  • the master clock node uses the master clock node as the destination master clock node to achieve the purpose of selecting the destination master clock node according to the configured link quality selection policy.
  • the master clock node when the master clock node is a two-step clock, the number of corresponding follow-up messages received is counted in the number of received packets.
  • the master clock node When the master clock node is a two-step clock, that is, the time at which the master clock node sends the synchronization packet is not carried by the timestamp, and the synchronization packet is sent to the slave clock node, but After sending the synchronization packet, the master clock node notifies the slave clock node of the time at which the slave clock node sends the synchronization packet by sending the following message including the time when the master clock node sends the synchronization packet, in this case, the slave clock.
  • the node counts the number of corresponding following packets received into the number of received packets, so as to calculate the link loss rate.
  • the present invention also provides a slave clock node for selecting a master clock node based on PTP and link quality, including:
  • the configuration module 801 is configured to configure a link quality selection policy according to the link quality indicator, where the link quality indicator includes: a link loss rate, and/or a delay jitter, and/or a link delay.
  • the selecting module 802 is configured to select a destination main clock node according to the configured link quality selection policy.
  • the link quality selection policy includes: a first criterion for selecting a target primary clock node by using a link loss rate as a first judgment indicator, and using a delay jitter and/or a link delay as a second judgment indicator; And/or, using the delay jitter as the first judgment indicator, selecting the second strategy of the destination master clock node by using the link loss rate and/or the link delay as the second judgment indicator; and/or The time is the first judgment indicator, and the third strategy of selecting the destination master clock node by using the link loss rate and/or the delay jitter as the second judgment indicator.
  • the selection module 802 can include:
  • the obtaining unit 8021 is configured to obtain a value when the destination primary clock node is selected by using the first policy.
  • the selecting unit 8022 is configured to select a corresponding primary clock node as the destination primary clock node according to the value of the link loss ratio of the link, or according to a link loss ratio and a value of delay jitter and/or link delay.
  • the selection unit 8022 is the most The small link loss rate or the minimum link loss rate is combined with the minimum delay jitter and/or link delay to select the destination primary clock node.
  • the obtaining unit 8021 is further configured to: when the target primary clock node is selected by using the second policy, obtain a value of delay jitter, or obtain a delay jitter and a link loss ratio. / or the value of the link delay;
  • the selecting unit 8022 is further configured to select the corresponding primary clock node as the destination primary clock node according to the value of the delay jitter or according to the delay jitter and the link loss rate and/or the link delay value.
  • the obtaining unit 8021 obtains the value of the delay jitter, or obtains the value of the delay jitter and the link loss rate and/or the link delay, and the selecting unit 8022 is configured therein.
  • the minimum delay jitter or minimum delay jitter is combined with the minimum link loss rate and/or link delay to select the destination primary clock node.
  • the obtaining unit 8021 is further configured to: when selecting the destination primary clock node by using the third policy, obtain a link delay value, or obtain a link delay value and a link loss ratio and/or The value of the delay jitter;
  • the selecting unit 8022 is further configured to select the corresponding primary clock node as the destination primary clock node according to the value of the link delay or according to the link delay and the link loss rate and/or the value of the delay jitter.
  • the obtaining unit 8021 obtains the link delay.
  • the minimum link delay or the minimum link delay is combined with the minimum link loss rate and/or delay jitter to select the destination primary clock node.
  • the obtaining unit 8021 may include:
  • the sending subunit 80211 is configured to send, to the corresponding primary clock node, a management message or a signal message carrying an interval and duration of the synchronization message sent by the desired primary clock node;
  • a receiving subunit 80212 configured to receive the master clock node at the interval for the duration
  • the time-sent synchronization message carrying the first timestamp indicating the synchronization time of the synchronization message
  • the obtaining sub-unit 80213 configured to acquire a second timestamp indicating the time of receiving the synchronization message, according to the synchronization message
  • the clock identifier identifies a primary clock node that sends the synchronization packet, and saves related information of the primary clock node;
  • a message counting sub-unit 80214 configured to count the number of received synchronization packets plus one count into the number of received messages
  • the sending sub-unit 80211 is further configured to send a delay request message to the primary clock node, and the obtaining sub-unit 80213 is further configured to obtain a third timestamp indicating the sending time of the delayed request message;
  • the receiving subunit 80212 is further configured to receive, by the primary clock node, a delayed response packet that includes a fourth timestamp indicating a time when the delay request packet is received;
  • a calculating subunit 80215 configured to calculate a value of each link delay according to the first timestamp, the second timestamp, the third timestamp, and the fourth timestamp;
  • the number of packets actually received from the clock node is the ratio of the number of received packets to the theoretical expected value.
  • the present invention further provides a system 1 for selecting a master clock node based on PTP and link quality, including the slave clock node 10 in the above embodiment, and a plurality of masters connected to the slave clock node 10 through the switch. Clock node 11.
  • the step of synchronizing the clock is performed by performing 1588 interaction with the destination master clock node.
  • a user selects a link quality (including a link loss ratio, and/or a delay jitter, and/or a link delay) to select a policy, and combines the link quality selection policy according to the user configuration.
  • the PTP protocol selects the destination master clock node, which not only satisfies the actual selection needs of the user.
  • the method further improves the multi-selectivity and flexibility when acquiring the master clock node, and solves the problem that the master clock node cannot select the master clock node when the master clock node does not send the advertisement message.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

La présente invention décrit un procédé permettant de sélectionner un noeud d'horloge maître basé sur un protocole de précision temporelle (PTP) et sur une qualité de liaison. Le procédé inclut les étapes suivantes consistant à : configurer une politique de sélection de qualité de liaison selon un index de qualité de liaison, l'index de qualité de liaison comprenant un rapport de perte de paquet de liaison, et/ou une instabilité de temps de propagation et/ou un temps de propagation de liaison ; sélectionner un nœud d'horloge maître cible selon la politique de sélection de qualité de liaison configurée. La présente invention illustre également un nœud d'horloge esclave et un système permettant de sélectionner un nœud d'horloge maître basé sur un protocole PTP et une qualité de liaison. La présente invention non seulement satisfait l'exigence de sélection proprement dite d'un utilisateur, mais aussi améliore la multi-sélectivité et la souplesse d'obtention du nœud d'horloge maître, et résout le problème selon lequel, dans un réseau téléphonique privé (PTN) traditionnel, un nœud d'horloge maître ne peut pas être sélectionné lorsque le nœud d'horloge maître n'envoie pas un message de notification.
PCT/CN2011/076233 2010-06-24 2011-06-23 Procédé, noeud d'horloge esclave et système permettant de sélectionner un noeud d'horloge maître basé sur un protocole de précision temporelle (ptp) et sur une qualité de liaison WO2011160595A1 (fr)

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