WO2013178148A1 - Procédé de synchronisation d'horloge et dispositif pour réseau de communication - Google Patents

Procédé de synchronisation d'horloge et dispositif pour réseau de communication Download PDF

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Publication number
WO2013178148A1
WO2013178148A1 PCT/CN2013/079574 CN2013079574W WO2013178148A1 WO 2013178148 A1 WO2013178148 A1 WO 2013178148A1 CN 2013079574 W CN2013079574 W CN 2013079574W WO 2013178148 A1 WO2013178148 A1 WO 2013178148A1
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Prior art keywords
clock
node
clock node
module
port
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PCT/CN2013/079574
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English (en)
Chinese (zh)
Inventor
张卫娥
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中兴通讯股份有限公司
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Publication of WO2013178148A1 publication Critical patent/WO2013178148A1/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
    • H04J3/0685—Clock or time synchronisation in a node; Intranode synchronisation
    • H04J3/0688—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
    • 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
    • H04J3/0664—Clock or time synchronisation among packet nodes using timestamps unidirectional timestamps

Definitions

  • the present invention relates to the field of communication system technologies, and in particular, to a communication network clock synchronization method and apparatus.
  • Clock synchronization is critical to the communication system. Inconsistent clock frequencies of the transceiver devices of the communication device will cause errors such as bit errors, slip codes, and frame loss. Especially in wireless networks, there are strict requirements for high-precision synchronization. Wireless systems based on frequency division duplex FDD mode (such as WCDMA) need to maintain frequency synchronization between nodes, while wireless systems based on time division duplex TDD mode (such as CDMA2000, TD-SCDMA, WiMAX, LTE) need more Strict time synchronization to meet the roaming and switching of mobile services.
  • frequency division duplex FDD mode such as WCDMA
  • time division duplex TDD mode such as CDMA2000, TD-SCDMA, WiMAX, LTE
  • IEEE 1588 is called "Precision Clock Synchronization Protocol Standard for Network Measurement and Control Systems", referred to as PTP (Precision Time Protocol), for use in standard Ethernet or other distributed bus systems that use multicast technology. Sensors, actuators, and clocks in other end devices perform sub-microsecond synchronization.
  • Running the 1588 protocol in the communication network can not only realize service transmission, but also realize network time synchronization transmission, meet the requirements of time synchronization of different mobile wireless networks, effectively save system equipment investment, and reduce engineering installation and maintenance costs.
  • PTP A network that uses PTP is called a PTP domain, and a node in a PTP domain is called a clock node.
  • PTP defines three basic clock nodes:
  • BC (Boundary Clock): There are multiple PTP port parameters in the same PTP domain. Synchronize with time;
  • TC Transparent Clock
  • the port on the device that runs the protocol is called the port.
  • Slave Port The port that receives the synchronization time
  • Passive Port A port that neither receives the synchronization time nor sends the synchronization time to the outside.
  • All clock nodes in the PTP domain are organized in a master-slave hierarchy.
  • the master clock periodically advertises PTP packets (including advertisement packets, other common messages, and event messages).
  • the slave clock receives PTP packets from the master clock.
  • the time information and the time information of the node use a certain method to calculate the master-slave line delay and the master-slave time difference, and use the time difference to adjust the local time, so that the slave device time is kept consistent with the master time.
  • the master-slave port can be obtained by running the BMC (Best Master Clock) algorithm between clock nodes or manually on the clock node. Manual configuration or network topology changes are prone to clock ringing. Although this can be mitigated by the Spanning Tree Protocol, it does not solve the problem fundamentally.
  • BMC Best Master Clock
  • the A1 port of clock node A is the master port
  • the B1 port of clock node B is the slave port
  • the B2 port is the master port
  • the clock node C is The C1 port is a slave port
  • the C2 port is a master port
  • the clock node A's A2 port is a slave port.
  • the A1 port of the clock node A sends an advertisement message and other PTP messages
  • the B1 port of the clock node B receives the PTP message from the clock node, synchronizes with the clock node A, and sends a notification from the B2 port.
  • the C1 port of the clock node C receives the PTP message sent by the clock node B, synchronizes with the clock node B, and sends an advertisement message and other PTP messages from the C2 port;
  • the clock node A receives the clock node.
  • the PTP packet sent by C is synchronized with the clock node C, and the advertisement packet and other PTP packets are sent from the A1 port. In this way, the clock forms a loop. Due to the clock ringing problem, when a certain upstream clock in the network is deviated, the entire network clock will be degraded, which will have a great impact on data transmission. Summary of the invention
  • Embodiments of the present invention provide a communication network clock synchronization method and apparatus for effectively preventing clock ringing and ensuring normal synchronization between clock nodes in a network.
  • the embodiment of the invention provides a communication network clock synchronization method, which includes:
  • the step of performing time synchronization operation on the first clock node by using the time information of the other PTP packet and the time information of the first clock node includes:
  • the time information of the other PTP packet and the time information of the first clock node are determined. Performing a time synchronization operation on the first clock node;
  • the method further comprises:
  • the grandparent clock ID in the advertisement packet is the same as the clock ID of the first clock node itself, it is confirmed that there is a clock ringing risk, and no time is performed. Synchronous operation.
  • the method further comprises: Extracting a step size in the notification text when determining that the first clock node needs to synchronize with the upstream clock node;
  • the step size in the advertisement message is Less than or equal to the step size recorded by the first clock node
  • the time information according to the other PTP message and the time information of the first clock node are used to A clock node performs time synchronization operations.
  • the method further includes:
  • the timeout timer is started
  • the embodiment of the invention further provides a clock node, including:
  • a receiving module configured to: receive an advertisement packet and other PTP packets sent by an upstream clock node;
  • An extraction module configured to: when determining that the clock node needs to synchronize with the upstream clock node, extracting a grandparent clock ID in the notification message;
  • a judging module configured to: determine whether the grandparent clock ID in the advertisement packet is the same as the clock ID of the own clock node, or determine whether the grandparent clock ID in the advertisement packet is the same as the clock ID recorded by the clock node ; as well as
  • a synchronization module configured to: determine, by the determining module, a grandfather clock in the notification message If the ID of the clock node is different from the clock ID of the clock node or the clock ID of the clock node is different from the clock ID recorded by the clock node, the time information of the other PTP packet and the time information of the clock node are determined. Perform time synchronization on this clock node.
  • the determining module includes:
  • the port judging sub-module is configured to: determine whether the own port of the clock node includes a main port; the first clock ID judging sub-module is configured to: determine, at the port, that the sub-module determines that the own port of the clock node includes a main port Determining whether the grandparent clock ID in the notification text is the same as the clock ID of the own clock node itself;
  • a second clock ID judging sub-module configured to: when the port judging sub-module determines that the auto port does not include the main port, determining whether the grandparent clock ID in the notification text is the same as the clock ID recorded by the clock node;
  • the synchronization module includes:
  • a first synchronization sub-module configured to: when the first clock ID determination sub-module determines that the grandparent clock ID in the advertisement packet is different from the clock ID of the local clock node itself, according to the other PTP packet Time information and time information of the clock node perform time synchronization operation on the clock node;
  • a second synchronization sub-module configured to: when the second clock ID determination sub-module determines that the grandparent clock ID in the advertisement packet is different from the clock ID recorded by the local clock node, according to the other PTP packet.
  • the device further comprises:
  • the first risk warning module is configured to: determine, by the port, that the sub-module determines that the own port of the clock node includes a primary port, and the first clock ID determining sub-module determines the grandfather clock ID and the clock in the notification text.
  • the clock ID of the node itself is the same, it is confirmed that there is a risk of clock ringing and no time synchronization is performed.
  • the extracting module is further configured to: when determining that the clock node needs to synchronize with the upstream clock node, extract a step size in the notification text;
  • the determining module further includes a first step length determining submodule, configured to: determine, by the port, that the submodule determines that the own port of the clock node does not include the primary port, and the second clock ID determining submodule determines the If the clock ID of the grandfather in the notification is the same as the clock ID recorded by the clock node, it is determined whether the step size in the advertisement packet is less than or equal to the step size recorded by the clock node;
  • the second synchronization module is configured to: when the first step length determining submodule determines that the step size in the advertisement message is less than or equal to the step size recorded by the clock node, according to the other PTP message.
  • the device further includes a timer control module and a second risk warning module
  • the determining module further includes a second step determining submodule:
  • the timer control module is configured to: determine, in the first step, the submodule to determine the notification
  • the second step determining sub-module is configured to: when the timer control module determines that the timeout timer reaches the timeout period, determine whether the step size in the notification message continues to increase;
  • the second synchronization module is further configured to: when the second step determination sub-module determines that the step size in the advertisement packet remains stable, according to the time information of the other PTP packet and the time of the local clock node Information is time synchronized to the clock node;
  • the second risk warning module is configured to: when the second step determination sub-module determines that the step size in the advertisement message continues to increase, it is confirmed that a clock loop exists on the upstream network, and no time synchronization operation is performed.
  • the embodiment of the invention effectively prevents clock ringing from occurring, ensures normal synchronization between clock nodes in the network, adjusts its own strategy when there is a loop in the upstream, does not synchronize with a clock source with a loop, prevents clock degradation, and improves the clock. Synchronization quality.
  • FIG. 1 is a flow chart of a first embodiment of a communication network clock synchronization method according to the present invention
  • FIG. 2 is a flowchart of a second embodiment of a method for synchronizing a communication network clock according to the present invention
  • FIG. 3 is a flowchart of a third embodiment of a communication network clock synchronization method according to the present invention
  • 4 is a flowchart of a fourth embodiment of a communication network clock synchronization method according to the present invention
  • FIG. 5 is a flowchart of a fifth embodiment of a communication network clock synchronization method according to the present invention
  • FIG. 6 is a schematic structural diagram of a first embodiment of a clock node according to the present invention.
  • FIG. 7 is a schematic structural diagram of a second embodiment of a clock node according to the present invention.
  • FIG. 8 is a schematic structural diagram of a third embodiment of a clock node according to the present invention.
  • FIG. 9 is a schematic structural diagram of a fourth embodiment of a clock node according to the present invention.
  • FIG. 10 is a schematic structural diagram of a fifth embodiment of a clock node according to the present invention.
  • FIG. 11 is a schematic structural diagram of a sixth embodiment of a clock node according to the present invention.
  • FIG. 1 is a flowchart of a first embodiment of a communication network clock synchronization method according to the present invention.
  • the communication network clock synchronization method mentioned in this embodiment includes:
  • Step S101 The first clock node receives the advertisement packet and other PTP packets sent by the upstream clock node.
  • PTP defines event messages and normal messages.
  • An event message is a time message that contains the exact timestamp generated by the sender and receiver; normal messages do not require an exact timestamp.
  • the advertisement in the ordinary message carries information such as clock priority, clock quality level, clock precision, clock ID, step size, etc., and is used to establish a master-slave synchronization relationship between clock nodes.
  • Step S102 when it is determined that the first clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID in the notification message;
  • the grandfather clock ID refers to the clock ID of the clock node located at the top of the master-slave hierarchy.
  • the first clock node has a slave port, and receives an advertisement packet sent by the upstream clock node. After obtaining the required clock information, the first clock node can synchronize with the upstream clock node.
  • the clock information includes a clock priority, a clock Quality level, clock accuracy, clock ID and other information. If the clock priority of the acquired grandparent clock is higher than the clock priority of the first clock node, or the clock quality level of the grandparent clock is higher than the clock quality level of the first clock node, or the clock precision of the grandparent clock is higher than the first clock node.
  • the clock accuracy determines that the first clock node needs to be synchronized with the upstream clock node. In addition, after receiving the required clock information from the port, the first clock node needs to synchronize with the upstream clock node.
  • Step S103 when it is determined that the grandparent clock ID in the advertisement>3 is different from the clock ID of the first clock node itself or the grandfather clock ID in the notification message is different from the clock ID recorded by the first clock node, according to other PTP messages.
  • the time information and the time information of the first clock node perform a time synchronization operation on the first clock node.
  • the time synchronization operation is performed only when the grandparent clock ID in the advertisement packet is different from the clock ID of the clock node itself or the recorded clock ID; when the grandparent clock ID in the advertisement and the clock ID of the clock node itself are When the recorded clock IDs are the same, in order to avoid clock ringing after synchronization, or to avoid synchronization with the upstream clock node that already has a clock loop, the clock nodes are not synchronized, effectively preventing clock ringing from occurring and ensuring the network.
  • the normal synchronization between the clock nodes improves the synchronization quality.
  • the present invention is not limited to topology applications with loops, is equally applicable in topologies without loops, and avoids clock ringing problems that may be caused by topology changes.
  • FIG. 2 is a flowchart of a second embodiment of a communication network clock synchronization method according to the present invention.
  • Step S201 The first clock node receives the advertisement packet and other PTP packets sent by the upstream clock node.
  • Step S202 when it is determined that the first clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID in the notification message;
  • Step S203 determining whether the first port of the first clock node includes the main port; if yes, executing step S204; if not, executing step S205;
  • the first clock node performs different processing according to its own port type.
  • the port category mainly includes the primary port and the secondary port. When the packet is advertised, the primary port sends the packet to the secondary port.
  • Step S204 determining the grandfather clock ID in the notification >3 ⁇ 4 text and the clock of the first clock node itself When the IDs are different, the time synchronization operation is performed on the first clock node according to the time information of the other PTP packets and the time information of the first clock node;
  • the clock node including the primary port transmits data to the downstream clock node during data transmission, and also transmits its own time information to the downstream clock.
  • To determine whether the received clock will form a loop compare the grandparent clock ID in the advertisement message with the clock ID of the first clock node itself. When the same, it indicates that the clock is the first clock node to publish itself. After being synchronized by each clock node in the network, it is transmitted back to itself. If the time synchronization operation is performed according to the time information received this time, a clock loop is formed.
  • the time synchronization operation is performed only when the grandparent clock ID in the advertisement message is different from the clock ID of the first clock node itself.
  • the first clock node since the first clock node includes the primary port, after the synchronization, the first clock node also sends an advertisement packet and other PTP packets to the downstream clock node to implement time synchronization of the communication network.
  • Step S205 Perform a time synchronization operation on the first clock node according to the time information of the other PTP packets and the time information of the first clock node, when the grandfather clock ID in the advertisement packet is different from the clock ID recorded by the first clock node. .
  • the slave port When the clock node only includes the slave port, the slave port performs the time synchronization operation according to the situation, and records the grandparent clock ID in the advertisement packet advertised by the upstream clock node. To determine whether the clock of the upstream network is looped, compare the grandparent clock ID in the advertisement packet with the clock ID recorded by the clock node. When the same, the clock ringing occurs after synchronization, or the clock ring is avoided.
  • the upstream clock nodes of the path are synchronized, and the clock nodes are not synchronized. This embodiment effectively prevents clock ringing from occurring and ensures normal synchronization between clock nodes in the network. At the same time, it adjusts its own policy when there is a loop upstream, and does not synchronize with the clock source with loops to prevent clock degradation and improve. Synchronized quality.
  • FIG. 3 is a flowchart of a third embodiment of a communication network clock synchronization method according to the present invention.
  • Step S301 The first clock node receives the advertisement packet and other PTP packets sent by the upstream clock node.
  • Step S302 when it is determined that the first clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID in the notification message;
  • Step S303 determining whether the first port of the first clock node includes the main port; if yes, executing step S304; if not, executing step S307;
  • Step S304 determining whether the grandfather clock ID in the advertisement >3 ⁇ 4 is the same as the clock ID of the first clock node itself; if yes, executing step S305; if not, executing step S306;
  • Step S305 confirming that there is a risk of clock ringing, and not performing time synchronization operation
  • the clock node including the primary port transmits data to the downstream clock node during data transmission, and also transmits its own time information to the downstream clock.
  • the grandparent clock ID in the advertisement packet is compared with the clock ID of the first clock node itself.
  • the clock is issued by the first clock node. After each clock node in the network synchronizes, it returns to itself. If the time synchronization operation is performed according to the time information received this time, a clock loop will occur, so time synchronization operation cannot be performed.
  • Step S306 Perform time synchronization operation on the first clock node according to time information of other PTP packets and time information of the first clock node.
  • Step S307 determining whether the grandfather clock ID in the notification text is the same as the clock ID recorded by the first clock node; if yes, executing step S308; if not, executing step S306;
  • Step S308 the flow of the step judgment is entered.
  • the slave port When the clock node only includes the slave port, the slave port performs the time synchronization operation according to the situation, and records the grandparent clock ID in the advertisement packet advertised by the upstream clock node. To determine whether the clock of the upstream network is looped, compare the grandparent clock ID in the advertisement packet with the clock ID recorded by the clock node. When the same, the clock ringing occurs after synchronization, or the clock ring is avoided. The upstream clock node of the path is synchronized, and the time synchronization operation cannot be performed temporarily. The step size is further determined. The process of determining the step size is described in detail in the subsequent embodiments.
  • This embodiment effectively prevents the occurrence of clock ringing, and ensures that the clock nodes in the network are normally the same. At the same time, when the loop exists upstream, the strategy is adjusted, and the clock source is not synchronized with the clock source to prevent clock degradation and improve the synchronization quality.
  • FIG. 4 is a flowchart of a fourth embodiment of a communication network clock synchronization method according to the present invention.
  • Step S401 The first clock node receives the advertisement packet and other PTP packets sent by the upstream clock node.
  • Step S402 when it is determined that the first clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID and the step size in the notification message;
  • Step S403 determining whether the current port of the current clock node includes the primary port; if yes, executing step S404; if not, executing step S407;
  • Step S404 determining whether the grandfather clock ID in the advertisement is the same as the clock ID of the current clock node itself; if yes, executing step S405; if not, executing step S406;
  • Step S405 confirming that there is a risk of clock ringing, and not performing a time synchronization operation
  • Step S406 Perform time synchronization operation on the first clock node according to time information of other PTP packets and time information of the first clock node.
  • Step S407 determining whether the grandfather clock ID in the notification text is the same as the clock ID recorded by the first clock node; if yes, executing step S408; if not, executing step S406;
  • Step S408 determining whether the step size in the advertisement message is less than or equal to the step size recorded by the first clock node; if yes, executing step S406; if not, executing step S409;
  • Step S409 the flow of the step stability judgment is entered.
  • the step size in the received advertisement message is compared with the step size of the record. If the step size in the advertisement packet is less than or equal to the step size recorded by the clock node, it indicates that the step size is normal and should be adjusted synchronously. If the step size is increased, the upstream network may have a loop. To perform synchronization adjustment, it is necessary to further judge the step stability, otherwise the clock will be degraded. The process of determining the stability of the step is described in detail in the subsequent embodiments. In this embodiment, the clock loop can be discovered and eliminated in time without the dependency of the spanning tree or the spanning tree, and the clock nodes in the network can be synchronized normally. When there is a loop in the upstream, the policy can be adjusted. Synchronize the clock source to effectively prevent the clock from being inferior Chemical.
  • FIG. 5 is a flowchart of a fifth embodiment of a communication network clock synchronization method according to the present invention.
  • Step S501 The first clock node receives the advertisement packet and other PTP packets sent by the upstream clock node.
  • Step S502 When it is determined that the first clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID and the step size in the advertisement.
  • Step S503 determining whether the first port of the first clock node includes the main port; if yes, executing step S504; if not, executing step S507;
  • Step S504 determining whether the grandfather clock ID in the advertisement >3 ⁇ 4 is the same as the clock ID of the first clock node itself; if yes, executing step S505; if not, executing step S506;
  • Step S505 confirming that there is a risk of clock ringing, and not performing a time synchronization operation
  • Step S506 Perform time synchronization operation on the first clock node according to time information of other PTP packets and time information of the first clock node.
  • Step S507 determining whether the grandfather clock ID in the advertisement message is the same as the clock ID recorded by the first clock node; if yes, executing step S508; if not, executing step S506;
  • Step S508 determining whether the step size in the advertisement message is less than or equal to the step size recorded by the first clock node; if yes, executing step S506; if not, executing step S509;
  • Step S509 starting a timeout timer
  • Step S510 when it is determined that the timeout timer reaches the timeout period, it is determined whether the step size in the advertisement message continues to increase; if not, step S506 is performed; if yes, step S511 is performed;
  • Step S511 it is confirmed that there is a clock loop in the upstream network, and no time synchronization operation is performed.
  • FIG. 6 is a schematic structural diagram of a first embodiment of a clock node according to the present invention.
  • the clock node mentioned in this embodiment includes:
  • the receiving module 10 is configured to receive an advertisement message and other PTP messages sent by the upstream clock node, and the extracting module 20 is configured to: when determining that the clock node needs to synchronize with the upstream clock node, extract the grandfather clock ID in the notification message ;
  • the determining module 30 is configured to determine whether the grandparent clock ID in the advertisement packet is the same as the clock ID of the clock node itself or whether the grandparent clock ID in the advertisement packet is the same as the clock ID recorded by the clock node.
  • the synchronization module 40 is configured to: when the determining module 30 determines that the grandparent clock ID in the advertisement packet is different from the clock ID of the own clock node itself or determines that the grandparent clock ID in the advertisement is different from the clock ID recorded by the clock node, The time information of other PTP packets and the time information of the local clock node perform time synchronization operations on the clock node.
  • the PTP defines an event message and a normal message.
  • An event message is a time message that contains the exact timestamp generated by the sender and the receiver; normal messages do not require an exact timestamp.
  • the advertisement message in the ordinary message carries information such as clock priority, clock quality level, clock precision, clock ID, and step size, and is used to establish a master-slave synchronization relationship between clock nodes.
  • the grandfather clock ID refers to the clock ID of the clock node located at the top of the master-slave hierarchy.
  • the clock node has a slave port that receives the advertisement packet sent by the upstream clock node. After obtaining the required clock information, it can synchronize with the upstream clock node.
  • the clock information includes information such as a clock priority, a clock quality level, a clock precision, and a clock ID. If the clock priority of the acquired grandparent clock is higher than the clock priority of the clock node, or the clock quality level of the grandparent clock is higher than the clock quality level of the clock node, or the clock precision of the grandparent clock is higher than the clock precision of the clock node, or Other algorithms determine that the clock node needs to be synchronized with the upstream clock node. In addition, after receiving the required clock information from the port, the clock node needs to synchronize with the upstream clock node.
  • the time synchronization operation is performed only when the grandparent clock ID in the advertisement packet is different from the clock ID of the clock node itself or the recorded clock ID; when the grandparent clock ID in the advertisement message and the clock ID of the clock node itself are When the recorded clock IDs are the same, in order to avoid clock ringing after synchronization, the clock nodes are not synchronized, which effectively prevents the clock from ringing and ensures that the clock nodes in the network are positive. Constant synchronization, improving the quality of synchronization.
  • the present invention is not limited to topology applications with loops, is equally applicable in topologies without loops, and avoids clock ringing problems that may be caused by topology changes.
  • FIG. 7 is a schematic structural diagram of a second embodiment of a clock node according to the present invention.
  • the judgment module 30 includes:
  • the port judging sub-module 31 is configured to determine whether the own port of the clock node includes a main port.
  • the first clock ID judging sub-module 32 is configured to determine when the port judging sub-module 31 determines that the own port of the clock node includes the main port.
  • the grandfather clock ID in the notification>3 ⁇ 4 text is the same as the clock ID of the clock node itself;
  • the second clock ID judging sub-module 33 is configured to determine, when the port judging sub-module 31 determines that the auto port does not include the main port, whether the grandparent clock ID in the advertisement packet is the same as the clock ID recorded by the clock node;
  • the synchronization module 40 includes:
  • the first synchronization sub-module 41 is configured to: according to the time information of the other PTP packet and the local clock node, when the first clock ID determination sub-module 32 determines that the grandparent clock ID in the advertisement packet is different from the clock ID of the local clock node itself Time synchronization information is performed on the clock node; the second synchronization sub-module 42 is configured to, when the second clock ID determination sub-module 33 determines that the grandparent clock ID in the advertisement packet is different from the clock ID recorded by the clock node,
  • the time information of other PTP packets and the time information of the local clock node perform time synchronization operations on the clock node.
  • the clock node performs different processing according to its own port type.
  • the port category mainly includes the primary port and the secondary port.
  • the primary port sends the packet to the secondary port.
  • the clock node including the primary port transmits data to the downstream clock node during data transmission, it also transmits its own time information to the downstream clock node.
  • the time synchronization operation is performed when the grandfather clock ID is different from the clock ID of the clock node itself.
  • the slave port performs the time synchronization operation according to the situation, and records the grandparent clock ID in the advertisement packet advertised by the upstream clock node.
  • the clock ringing is avoided after synchronization, or the clock ring is avoided.
  • the upstream clock nodes of the path are synchronized, and the clock nodes are not synchronized.
  • This embodiment effectively prevents clock ringing from occurring and ensures normal synchronization between clock nodes in the network.
  • it adjusts its own policy when there is a loop upstream, and does not synchronize with the clock source with loops to prevent clock degradation and improve. Synchronized quality.
  • FIG. 8 is a schematic structural diagram of a third embodiment of a clock node according to the present invention.
  • the clock node also includes:
  • the first risk warning module 51 is configured to determine, at the port determining sub-module 31, that the own port of the clock node includes a primary port, and the first clock ID determining sub-module 32 determines the grandparent clock ID in the advertisement packet and the local clock node itself. When the clock ID is the same, it is confirmed that there is a risk of clock ringing and no time synchronization is performed.
  • the clock node including the primary port transmits data to the downstream clock node during data transmission, and also transmits its own time information to the downstream.
  • Clock node for synchronous operation of downstream clock nodes.
  • To prevent the clock from being formed into a loop compare the grandparent clock ID in the advertisement packet with the clock ID of the clock node itself. If the clock ID is the same, the clock is self-published by the clock node. After the clock node is synchronized, it is transmitted back to itself. If the time synchronization operation is performed according to the time information received this time, a clock loop is formed, so the time synchronization operation cannot be performed.
  • This embodiment effectively prevents the occurrence of clock ringing and ensures normal synchronization between clock nodes in the network.
  • FIG. 9 is a schematic structural diagram of a fourth embodiment of a clock node according to the present invention.
  • the extracting module 20 is further configured to: when determining that the clock node needs to synchronize with the upstream clock node, extract the step size in the notification message;
  • the judging module 30 further includes a first step length judging sub-module 34, configured to determine at the port judging sub-module 31 that the own port of the clock node does not include the main port, and the second clock ID judging sub-module 33 determines the grandfather in the notice 4 When the clock ID is the same as the clock ID recorded by the clock node, it is determined whether the step size in the advertisement is less than or equal to the step size recorded by the clock node;
  • the second synchronization module 42 is configured to: according to the step information of the other PTP packet and the clock node, when the step size of the first packet is determined by the first step determining sub-module 34, the step size in the advertisement packet is less than or equal to the step size recorded by the clock node.
  • the time information performs time synchronization operation on the clock node.
  • the slave port when the clock node includes only the slave port, the slave port performs the time synchronization operation according to the situation, and records the grandparent clock in the advertisement packet issued by the upstream clock node. ID.
  • To determine whether the clock of the upstream network is looped compare the grandparent clock ID in the advertisement packet with the clock ID recorded by the clock node. When the same, the clock ringing is avoided after synchronization, or the clock ring is avoided.
  • the upstream clock nodes of the path are synchronized, and the clock nodes are not synchronized.
  • the step size in the received advertisement message is compared with the step size of the record.
  • step size in the advertisement packet is less than or equal to the step size recorded by the clock node, it indicates that the step size is normal and should be adjusted synchronously. If the step size is increased, the upstream network may have a loop. Make a synchronization adjustment, otherwise it will cause the clock to deteriorate. In this embodiment, the clock loop can be discovered and eliminated in time without the dependency of the spanning tree or the spanning tree, and the clock nodes in the network can be synchronized normally. When there is a loop in the upstream, the policy can be adjusted. The clock source is synchronized to effectively prevent clock degradation.
  • FIG. 10 is a schematic structural diagram of a fifth embodiment of a clock node according to the present invention.
  • the communication network clock synchronization device further includes a timer control module 60 and a second risk warning module 52.
  • the determination module 30 further includes a second step determination sub-module 35:
  • the timer control module 60 is configured to start the timeout timer when the first step length determining submodule 34 determines that the step size in the advertisement message is greater than the step size recorded by the clock node;
  • the second step determining sub-module 35 is configured to determine whether the step size in the notification message continues to increase when the timer control module 60 determines that the timeout timer reaches the timeout period;
  • the second synchronization module 42 is further configured to: when the second step determination sub-module 35 determines that the step size in the advertisement packet is stable, the clock node performs the clock information according to the time information of the other PTP packet and the time information of the local clock node.
  • the time synchronization operation module is configured to: when the second step determination sub-module 35 determines that the step size in the advertisement message continues to increase, confirm that the upstream network has a clock loop and does not perform a time synchronization operation.
  • the step size continues to increase within the timeout period, it indicates that there is a loop in the upstream network, and synchronization adjustment cannot be performed, otherwise the clock will be deteriorated.
  • the clock loop can be discovered and eliminated in time without relying on the spanning tree or spanning tree failure, so as to ensure normal synchronization between clock nodes in the network.
  • the strategy is adjusted, and the clock source is not synchronized with the clock source, thereby preventing clock degradation and improving synchronization quality.
  • FIG. 11 is a schematic structural diagram of a sixth embodiment of a clock node according to the present invention.
  • the clock node also includes:
  • the sending module 70 is configured to: when the port determining sub-module 31 determines that the own port of the clock node includes the master port, send the advertisement packet and other PTP packets after the time synchronization operation of the first synchronization sub-module 41 to the downstream clock node. Or after the first risk warning module 51 confirms that the time synchronization operation is not possible, the advertisement message and other PTP messages are sent to the downstream clock node.
  • the clock node includes the primary port. After the synchronization, the clock node sends an advertisement packet and other PTP packets to the downstream clock node to implement time synchronization of the communication network.
  • each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may use software functions.
  • the form of the module is implemented. The invention is not limited to any specific form of combination of hardware and software.
  • the embodiment of the present invention effectively prevents clock ringing from occurring, ensures normal synchronization between clock nodes in the network, adjusts its own policy when there is a loop in the upstream, and does not synchronize with a clock source with a loop to prevent clock degradation. , improved synchronization quality.

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

Abstract

L'invention concerne un procédé de synchronisation d'horloge et un dispositif pour un réseau de communication. Le procédé comprend les étapes suivantes : la réception, par un premier noeud d'horloge, d'un message de notification et d'autres messages PTP envoyés par un noeud d'horloge amont; lorsqu'il est déterminé que le premier noeud d'horloge doit réaliser une synchronisation avec le noeud d'horloge amont, l'extraction d'un ID d'horloge maître dans le message de notification ; et lorsqu'il est jugé que l'ID d'horloge maître dans le message de notification est différent de l'ID d'horloge du premier noeud d'horloge per se, ou lorsqu'il est jugé que l'ID d'horloge maître dans le message de notification est différent d'un ID d'horloge enregistré par le premier noeud d'horloge, en fonction des informations temporelles relatives aux autres messages PTP et des informations temporelles relatives au premier noeud d'horloge, la mise en oeuvre d'une opération de synchronisation temporelle sur le premier noeud d'horloge.
PCT/CN2013/079574 2012-08-09 2013-07-18 Procédé de synchronisation d'horloge et dispositif pour réseau de communication WO2013178148A1 (fr)

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