JP2019068190A - Network apparatus - Google Patents

Abstract

To arbitrarily select a master of time synchronization, cancel it, and monitor a state change between the master and a slave in a network with time synchronization function.SOLUTION: PTP hubs 1-6 are network apparatuses capable of functioning as a master or slave of time synchronization. For example, in the case where the PTP hub 4 is a slave, if reception of a regular time synchronization packet from a PTP hub 2, which is a master, is interrupted, the PTP hub 4 notifies other slaves (for example, PTP hubs 5 and 6) belonging to the same network as the PTP hub 4 of a master communication abnormality notification packet without performing reception timeout of the time synchronization packet and on the other hand selects a new master from a slave group belonging to the network.SELECTED DRAWING: Figure 7

Description

  The present invention relates to the function of a network device compliant with PTP (Precision Time Protocol).

  PTP is a protocol for realizing highly accurate time synchronization by restricting the usage environment to LAN, and its specification is defined as IEEE 1588.

  In a network compatible with PTP, a grand master (hereinafter, master) transmits a high-precision time synchronization packet, and a slave receives the time synchronization packet (Patent Document 1). PTP achieves a timestamp accuracy of less than microsecond RMS by the function of hardware timestamps implemented in MAC (Media Access Control) and PHY (Physical layer) of a network interface chip.

  There are two versions of PTP. Version (1) has a Boudary Clock (BC) that separates segments to perform large-scale expansion. In version (2), a switching hub Transparent Clock (TC) with delay management function is provided, enabling more flexible and accurate deployment.

JP, 2013-118502, A

  The PTP hub is used with the other devices in the configuration shown in FIG. When all PTP hub operations are complete, one PTP hub will be the master, the other PTP hubs will be slaves, and the PTP hubs of the other slaves will synchronize at the time of the master PTP hub (in Figure 5, the master PTP hubs 1 and 3 which are other slaves are synchronized with a certain PTP hub 2). After this, the master PTP hub transmits PTP packets in a fixed cycle to maintain synchronization with the other slave PTP hubs (see FIG. 6). The PTP hub of the slave that has acquired the PTP packet for maintaining synchronization is a PTP packet received to a port (called a PTP port including the master port) used for PTP processing other than the port that received the PTP packet (called the master port) (The process of transferring a received packet to another PTP hub is called a transparent process). When the PTP hub is synchronized, as shown in FIG. 7A or 8B, if an error occurs in the network between the master PTP hub and the slave PTP hub and communication is interrupted, PTP packets transmitted from the master PTP hub at regular intervals will not reach the slave PTP hub. After this, the slave PTP hub that can not receive PTP packets from the master waits for the PTP packet reception waiting time-out time (Fig. 7 (b), Fig. 8 (c)). A selection process is performed to select another master from the slave PTP hubs (FIG. 7 (d) or FIG. 9 (b)).

  When the above master switching process is performed, it takes about ten seconds to complete switching to another master and synchronization from the occurrence of a network abnormality between master and slave. In addition, since synchronization processing with the master can not be performed during this period, a synchronization shift of several tens of microseconds to several hundreds of microseconds (depending on the accuracy of the crystal used) occurs before synchronization with another master is started. The above-mentioned deviation in synchronization occurs when one master switching occurs, and when there are a plurality of units, there is a possibility that master switching may occur multiple times between PTP hubs depending on the timing of abnormality determination. . In that case, since multiple master switching occurs, the final master switching is completed and more time is required to synchronize. In systems where synchronization must always be kept below 10 μsec, this value is fatal.

  An object of the present invention is to speed up master switching at the time of disconnection of a communication line or failure of a hub in a network having a time synchronization function.

  Therefore, one aspect of the present invention is a network device capable of functioning as a master or slave of time synchronization, and when the network device is a slave, reception of periodic time synchronization packets from the master is discontinued. While notifying the master communication abnormality notification packet to other slaves belonging to the network of the network device without executing the reception timeout of the time synchronization packet, a new master is selected from the group of slaves belonging to the network.

  In one aspect of the present invention, when the network device receives notification of the master communication error notification packet from another slave belonging to the network, the master communication error notification packet is notified to the other slave on the load side of the network device. While selecting a new master from the group of slaves belonging to the network.

  One aspect of the present invention is that the network is a duplexed network.

  According to the present invention described above, in a network having a time synchronization function, master switching can be performed at high speed in the event of disconnection of a communication line or failure of a hub.

11 is a flowchart of link-down detection processing of a master port according to an embodiment of the present invention. 6 is a flowchart of master communication error notification packet reception processing according to an embodiment of the present invention. The flowchart of the master switching high-speed processing (the 1) in the embodiment of the present invention. The flowchart of the master switching high speed processing (the 2) in embodiment of this invention. (A) Network configuration diagram of a single VLAN according to an embodiment of the present invention, (b) Network configuration diagram of a duplexed VLAN according to an embodiment of the present invention. (A) An explanatory view of a normal operation example of a network device in a single VLAN, (b) An explanatory view of a normal operation example of a network device in a dual VLAN. (A) An explanatory diagram when a network abnormality occurs in a single VLAN, (b) An operation explanatory diagram of a network device (conventional) when the network abnormality occurs, and (c) an operation explanation of the network device when the network abnormality occurs (the present invention) FIG. 8D is an operation explanatory diagram of master selection when a network abnormality occurs in a single VLAN. (A) An explanatory diagram when a network abnormality occurs in a redundant VLAN, (b) An explanatory diagram when a master abnormality occurs in the VLAN, (c) An operation explanatory diagram of a network device (conventional) when the network abnormality occurs. (A) Operation explanatory drawing of the network apparatus (this invention) at the time of network abnormality generation | occurrence | production in duplication VLAN, (b) Operation | movement explanatory drawing of master selection at the time of network abnormality generation | occurrence | production in duplication VLAN.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the network illustrated in FIG. 5, the PTP hubs 1 to 6 of the present embodiment are network devices that form an aspect of a PTP-compliant L2 switching hub. Devices 21 to 26 are connected to the PTP hubs 1 to 6 as peripheral devices.

  PTP hubs 1 to 6 are also capable of time synchronization with the grand master, but by connecting PTP hubs and exchanging PTP packets between PTP hubs, the master can be automatically selected from among PTP hubs. It is possible for other PTP hubs to synchronize at the time of its master PTP hub. In order to maintain time synchronization, the PTP hub that has become the master transmits PTP packets (time synchronization packets) to other PTP hubs in a fixed cycle. In addition, all PTP hubs can notify the peripheral devices other than PTP at regular intervals of status information (hereinafter, PTP information packet) inside the PTP hub as an original function.

  The PTP hubs 1 to 6 implement the following processing functions (1) to (4).

  Related technical terms will be described in describing the processing functions (1) to (4).

  MS communication error notification non-transmission information: Information in which port information not transmitting MS communication error notification packet, and VLAN information for the same determination are stored.

  Master candidate DB: Information necessary for selecting a master transmitted from each PTP hub (domain number, ID number, priority information, etc.), reception port, affiliated VLAN information of received packet, selected master information, etc. are stored. Database.

  PTP setting information: Information in which information necessary for operating PTP processing, such as port information used as PTP processing, valid / invalid information of transparent processing, domain number, etc. is stored.

(1) Master port link down detection process (Figure 1)
S101: By registering in the existing state change detection process, when the type of state change is the link down (S101 ′), the process at the time of link down detection of the master port is called.

  S102: If the user is a master, the process is exited and the conventional PTP process is performed (S108).

  S103: The port whose link is down is obtained.

  S104: Clear MS communication error notification non-transmission information.

  S105: It is confirmed whether the link port and the master port of the master PTP hub in the master candidate database (hereinafter, master candidate DB) are the same. If the master port is not the same, the process exits and the conventional PTP process is performed (S108). When the master port is the same, after the link down port is stored in the MS communication abnormality notification non-transmission information, the master switching high-speed processing (processing in FIG. 3) is performed (S105 ').

  S106: It is confirmed whether master information exists in master candidate DB. If it exists, the conventional PTP process is performed, and if it does not exist, the process of S107 is performed.

  S107: Perform existing master selection processing.

(2) MS communication error notification packet reception process (see FIG. 2)
S201: Register MS communication error notification packet (use PTP packet for management also for master fast switching notification) in existing PTP packet reception process, and MS communication when MS communication error notification packet is received (S201 ') It is possible to execute an abnormality notification packet reception process (see FIG. 2).

  S202: If the user is the master, the process is exited and the conventional PTP process is performed (S207).

  S203: Clear MS communication error notification non-transmission information.

  S204: The port that has received the MS communication error notification packet and the associated VLAN are acquired and stored in the MS communication error notification non-transmission information.

  S205: Check whether the acquired reception port and the master port of the master PTP hub in the master candidate DB are the same. If they are the same, the process of S206 is performed. If they are not the same, the link down port is stored in the MS communication error notification non-transmission information, and then the master switching speed-up process (part 2) (the process of FIG. 4) is performed, and the process is exited.

  S206: After the master information is cleared from the master candidate DB, the master switching high-speed processing (part 2) (processing in FIG. 4) is performed (S206 '), and then the existing master selection processing is performed (S206' ').

(3) Master switching high-speed processing (part 1) (FIG. 3)
S301: The master information in the master candidate DB is cleared.

  S302: Check the existence of a VLAN other than the VLAN (Virtual Local Area Network) of the master information in the master candidate DB.

  S303: If another VLAN exists, another VLAN master switching process is performed (S304). If not, a master sorting process is performed (S310).

  S304: It is determined that another VLAN is valid (VALN is not in an invalid state, IP is set, etc.) (existing process).

  S305: If it is determined that the port is determined to be valid, it is determined that the port of another VLAN is valid (S306), and if it is determined that the port is invalid, the reception port of another VLAN in the master candidate DB is MS communication error notification non-transmission information Then, the other VLAN information is deleted from the master candidate DB (S305 '), and MS communication error notification transmission processing is performed (S310).

  S306: A port of another VLAN in the master candidate DB (a port receiving PTP packets as another VLAN from the master) is acquired.

  S307: It is determined that the acquired port is valid (link down, non-use setting and the like are not performed) (existing process).

  S308: If it is determined that it is valid, another VLAN master processing is performed (S309), and if it is determined that it is invalid, another VLAN information is deleted from the master candidate DB, and MS communication error notification transmission processing is performed (S308) S310).

  S309: After setting another VLAN in the master candidate DB as a master, the process exits.

  S310: In order to transmit an MS communication error notification packet, first, the validity and invalidity of the transparency processing in the PTP setting information are confirmed. If it is valid, the MS communication abnormality notification process is performed (S311), and if it is invalid, the process is not performed and the process is ended.

  S311: The PTP port is acquired from the PTP setting information (if there is more than one), the first port is acquired.

  S312: Since the MS communication error notification packet is not transmitted to the port on the master side, it is checked whether the PTP port is in the MS communication error notification non-transmission information. If it exists, the next PTP port acquisition process is performed (S316), and if it does not exist, a port validity determination process of the PTP port is performed (S313).

  S313: The existing port validity determination is performed on the PTP port.

  S314: If the PTP port is valid, MS communication abnormality notification packet transmission processing is performed (S315). If the PTP port is invalid, acquisition processing of the next PTP port is performed (S316).

  S315: Send an MS communication error notification packet from the PTP port.

  S316: The next PTP port is acquired from PTP setting information. If it can be acquired, the MS communication error notification transmission process is performed again (S312), and if it can not be acquired, the process is left.

(4) Master switching high-speed processing (part 2) (FIG. 4)
S401: In order to transmit an MS communication error notification packet, first, the validity / invalidity of the transparent processing in the PTP setting information is confirmed. If it is valid, the MS communication abnormality notification process is performed (S402), and if it is invalid, the process is not performed and the process is ended.

  S402: The PTP port is acquired from the PTP setting information (if there is more than one, the first PTP port).

  S403: Since the MS communication abnormality notification packet is not transmitted to the port on the master side, it is confirmed whether the PTP port is in the MS communication abnormality notification non-transmission information. If the PTP port exists, the next PTP port acquisition process is performed (S408). If the PTP port does not exist, the port validity determination process is performed on the PTP port (S404).

  S404: It is checked whether the VLAN to which the PTP port belongs is in the MS communication error notification non-transmission information. If it exists, the existing port validity determination process is performed on the PTP port (S405), and if it does not exist, the next PTP port acquisition process is performed (S408).

  S405: The existing port validity determination is performed on the PTP port.

  S406: If the PTP port is valid, MS communication error notification packet transmission processing is performed (S406). If the PTP port is invalid, the next PTP port acquisition processing is performed (S408).

  S407: Transmit an MS communication error notification packet from the PTP port.

  S408: The next PTP port is acquired from PTP setting information. If it can be acquired, the MS communication abnormality notification process is performed again (S404), and if it can not be acquired, the process is left.

  A specific operation example of the PTP hubs 1 to 6 having the following functions will be described.

[Operation example 1] Master high-speed switching in a single VLAN 1-1: Preconditions The PTP hubs 1 to 6 belonging to the network illustrated in FIG. 5 (a) are other slaves with one master selected. Synchronized with the PTP hub of

  Also, the transmission function of all PTP hubs (PTP hubs 1 to 6) is enabled (PTP packets can be transmitted), and as shown in FIG. 6A, PTP hub 2 which is a master PTP hub has a fixed cycle. The other slave PTP hubs use transparent processing to transfer the PTP packet to be transmitted.

1-2: Specific operation example It is assumed that a disconnection occurs between the PTP hub 3 and the PTP hub 4 illustrated in FIG. 7A.

In the case of the conventional processing, as shown in FIG. 7B, three PTP hubs 4 to 6 can not receive PTP packets from the master, and therefore, wait for a PTP packet reception timeout time, and shift to the master selection processing.
On the other hand, in the process of the present embodiment (the present invention), as shown in FIG. 6C, the PTP hub 4 detects the link down of the master port, and the PTP port on the PTP hub 5 The MS communication error notification packet (master communication error notification packet) is transmitted to the PTP port of (1), and the process immediately shifts to master selection processing (sends its own PTP information as a PTP packet to another hub).

  The PTP hub 5 that has received the MS communication error notification packet confirms the reception from the master side port, transmits the MS communication error notification packet to the PTP port on the PTP hub 6 side, and immediately performs master selection processing (your PTP Transfer information to other hubs as PTP packets.

  At this time, although the PTP hub 3 detects a link down, since it is not a port on the master side, the process of transmitting an MS communication abnormality notification packet is not performed.

  When the processing of the above-described conventional or present embodiment is performed, the PTP hub 4 is a master (immediately in the case of a novel) from among the PTP hub 4, the PTP hub 5, and the PTP hub 6 as shown in FIG. Elected and synchronized with PTP hubs 5 and 6.

[Operation example 2] Master high-speed switching in VLAN duplication 2-1: Preconditions The PTP hubs 1 to 6 of the network illustrated in FIG. 5 (b) are PTPs of other slaves in a state where one master is selected. Synchronize with the hub.

  The transparent function of all PTP hubs 1 to 6 is enabled (PTP packet can be transmitted), and as shown in FIG. 6B, other slave PTP hubs transmit PTP packets transmitted by the master PTP hub 2 at a constant cycle Transfer using. However, PTP packets are transmitted from the master to each VLAN (VLAN1, VLAN2) because the VLAN duplex setting is performed, but the slave PTP hub is synchronized with the PTP packet of VLAN1. Although this processing is different from the normal PTP processing, in order to perform high-speed switching in the same master using a duplexed VLAN, it is treated as another processing in the master determination processing. Therefore, even in the illustrated mode, even the same master is treated as different master information, and therefore, it is expressed as V1-slave when synchronized on the VLAN1 side and V2-slave when synchronized on the VLAN2.

2-2: Specific operation example It is assumed that a line disconnection occurs between the PTP hub 4 and the PTP hub 5 as shown in FIG. In this case, unlike the master high-speed switching in a single VLAN, since PTP hubs are duplexed by VLAN, high-speed VLAN switching in the same master is performed (PTP hub 5 and PTP hub 6 after line disconnection) Since the PTP packets of VLAN 1 and VLAN 2 are periodically transmitted from the master PTP hub 2, if it is determined that VLAN 1 is not transmitted, it is immediately synchronized to the VALN 2 side). Switching to another master does not occur. After this, the master port on the VLAN 2 side is also disconnected at the same time, or as shown in FIG. 6B, if the PTP hub 2 fails, master switching occurs. Therefore, as shown in FIG. 6B, it is assumed that the master PTP hub 2 has failed after the line disconnection.

In the case of the conventional processing, as shown in FIG. 6C, since three PTP hubs 4 to 6 can not receive PTP packets from the master, they wait for the PTP packet reception time-out period and shift to the master selection processing.
On the other hand, in the processing of this embodiment (the present invention), as shown in FIG. 9A, the PTP hub 3 detects the link down of the master port of VLAN 1 and immediately links down the port on the VLAN 2 side as well. Since it is possible to determine that it is not, the MS communication error notification packet (master communication error notification packet) is sent to the PTP ports of VLAN1 and VLAN2 on the PTP hub 4 side (PTP port of PTP hub on the load side). It shifts to processing (sends its own PTP information as PTP packet to other hubs).

  The PTP hub 4 that has received the MS communication error notification packets of VLAN 1 and VLAN 2 transmits the MS communication error notification packet to the same VLAN port other than the receiving port (the VLAN 1 side has a line disconnection state Since it has been sent, only the MS communication error notification of VLAN 2 is sent), and the process immediately shifts to master selection processing (sends its own PTP information as a PTP packet to another hub).

  The PTP hub 5 that has received the MS communication error notification packet of VLAN 2 transmits an MS communication error notification packet to the PTP port of VLAN 2 on the PTP hub 6 side, and immediately transitions to master selection processing (PTP information of its own PTP Send to other hubs as a packet).

  The PTP hub 6 having received the MS communication abnormality notification packet of the LAN 2 immediately shifts to master selection processing (transmits its own PTP information as a PTP packet to another hub) since there is no VLAN 2 port. At this time, the PTP hub 1 also detects the link down of the VLAN 1 port and VLAN 2 port on the master side similarly to the PTP hub 3, but since there is no port other than the port on the master side, it immediately shifts to master selection processing (own PTP information To other hubs as PTP packets).

  When the above-described conventional or new processing is performed, as shown in FIG. 7B, the PTP hub 1, the PTP hub 4, the PTP hub 5, and the PTP hub 6 (immediately in the case of the processing of this embodiment) PTP hub 4 And PTP hub 1 is elected as a master and immediately synchronizes with VLAN 2 of PTP hub 4 which is the master. Since one PTP hub 1 is isolated, there is no synchronization partner, but master selection is performed and it becomes an independent master.

As apparent from the description of the above operation examples 1 and 2, according to the network device of the present embodiment, the reception time out of the time synchronization packet is canceled when the periodic time synchronization packet from the time synchronization master is not received. While notifying the master communication abnormality notification packet to other slaves belonging to the network of the network device without executing the above, a new master is selected from the group of slaves belonging to the network. Also, when receiving notification of the master communication abnormality notification packet from another slave belonging to the network, the other slave on the load side of the network device is notified of the communication abnormality notification packet while the group of slaves belonging to the network Select a new master.
As described above, since information indicating the status is periodically transmitted by the master and all slaves can grasp the status of the master, when time synchronization with the master is lost, the slaves To speed up the time to select a new master from

  Therefore, even if the high speed processing is introduced, it does not affect the high speed master switching by VLAN duplication of the same master that realizes the conventional high speed.

  In addition, the introduction of the high-speed processing eliminates the need to wait for the reception time-out time, so that the speed of the conventional master switching is increased.

  Furthermore, by introducing the speed-up processing, it is possible to shift to the master selection processing all at once, so it is possible to suppress the occurrence of multiple master switchings due to the difference in the start timing of PTP packet reception timeout time determination.

  The above-described high-speed processing introduction effect enables master switching of several microseconds or less as compared with the conventional network device.

  The present invention is not limited to the embodiments described above, and can be implemented in various aspects within the scope of the claims of the present invention.

1 ... Network 1 to 6 ... PTP hub (network device)
21 to 26 ... equipment

Claims (3)

A network device capable of functioning as a time synchronization master or slave,
When the network device is a slave, if reception of periodic time synchronization packets from the master is discontinued, the master communication error notification packet belongs to the network device network without executing a reception timeout of the time synchronization packets. A network device that notifies a slave of while selecting a new master from the group of slaves belonging to the network. In the network device according to claim 1,
When receiving notification of the master communication abnormality notification packet from another slave belonging to the network, the other slave on the load side of the network device is notified of the communication abnormality notification packet while a new master from a group of slaves belonging to the network Network equipment to select.   The network device according to claim 1, wherein the network is a duplexed network.

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