JP2009296079A - Node device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a node device which does not impart excessive loads on other node devices which have already entered the network and does not adversely affect the processing speed and the communication speed, when the node device newly enters a network. <P>SOLUTION: The node device 1 includes: a packet observation function section 14 for extracting a node ID included in packets received from the other node device over a prescribed period; an entry determination function section 15 for checking the presence/absence of the overlap of the extracted node ID of the other node device and the node ID of the present device and determining the propriety of the entry to the network; and a network entry control section 16 for sending the received packet to the other node device until it is determined that the entry is possible in the entry determination function section 15, sending the received packet to a packet transmission/reception control section 13 and sending the packet from the packet transmission/reception control section 13 to the other node device after it is determined that the entry is possible. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a node device applied when a network system is configured by being connected to each other in a ring shape via a network.

  In a network system configured by connecting multiple node devices to each other via a network in the form of a ring, a new node device is added for system expansion, a node device is relocated, or a node device fails It is necessary to replace the device. In this case, when applied to highly public infrastructure such as electric power and traffic, the network system is always required to operate. Therefore, when adding, moving, or replacing node equipment, the network is disconnected for a long period of time. Therefore, it is required to allow the node device to enter within as short a time as possible.

Therefore, in the prior art, the following proposal has been made (for example, see Patent Document 1 below).
FIG. 10 shows a case where a plurality of node devices 1 (# 1 to # 4) are connected to each other via a network 3 in a ring shape to form a network system, and node devices (# 1 to # 3 that have already entered the network). ) Shows a state where a new node device (# 4) is about to enter.

  When the node device 1 (# 4) scheduled to newly enter is connected to the network 3, the node device 1 (# 4) enters a standby state to bypass the received packet to the other node devices 1 (# 1 to # 3). In this standby state, the newly entering node device 1 (# 4) transmits to the network 3 an entry request packet including a node ID preset in the own device.

  The other node devices 1 (# 1 to # 3) that have already entered the network 3 extract the node ID included in the received entry request packet, and this node ID is the same node ID that is set in the own device. In this case, an error bit is set in the entry request packet and transmitted. The node device 1 (# 4) that is scheduled to newly enter, if there is no error bit in the entry request packet that has returned around the ring, cancels the standby state and enables transmission / reception of the packet. Enter the network with the set node ID.

  On the other hand, if an error bit is set in the entry request packet that returns after a round, it is determined that the same node ID already exists in the other node devices 1 (# 1 to # 3) that have already entered the network. The standby state for bypassing is maintained as it is.

  Thereafter, in the node device 1 (# 4) scheduled to newly enter, when the node ID is changed, the standby state is canceled if the error bit is not set in the entry request packet that has returned after a round, and the changed node ID Therefore, it will enter the network 3.

JP-A-10-276198

  As described above, in the prior art described in Patent Document 1, the node device 1 (# 4) scheduled to newly enter the entry request packet including the node ID set in its own device when connected to the network 3 Is transmitted to the network 3, and the node IDs included in the packet are checked by other node devices 1 (# 1 to # 3) that have already entered the network, thereby checking whether or not the node IDs are duplicated. Judgment is made.

  However, if the node ID duplication check is performed by other node devices 1 (# 1 to # 3) that have already entered the network 3 as in the past, the load on the node devices that have already entered increases. For this reason, the processing speed of other node devices that have already entered and the communication speed of the network are adversely affected.

  The present invention has been made to solve the above-described problems. When a new entry is made to the network, the processing speed of the node device and the network can be reduced without giving an extra load to other already entered node devices. The purpose is not to adversely affect the communication speed.

  In order to achieve the above object, the present invention employs the following configuration in a node device for configuring a ring network system connected to each other via a network.

  That is, according to the present invention, a transfer control unit that generates a packet for transmission including at least its own node ID, destination address, and control data, and a packet generated by the transfer control unit are transmitted to the network. When the destination address included in the packet received from another node device matches the own address, the packet transmission / reception control unit that captures the packet and the node ID included in the packet received from the other node device A packet observation function extracted for a predetermined period, and whether or not the node ID of another node device extracted by the packet observation function unit overlaps with the node ID of the own device is checked to determine whether or not to enter the network. Receive until the entry determination function unit and the entry determination function unit determine that entry is possible. After the packet is sent to another node device and the entry determination function unit determines that entry is possible, the received packet is sent to the packet transmission / reception control unit, and the packet from the packet transmission / reception control unit is sent to the other node device. And a network entry control unit for sending.

  The node device according to the present invention does not cause other node devices that have already joined the network to check for duplicate node IDs when a new network is entered, but is sent from another node device exclusively in the newly joining node device. Since the node ID duplication check is performed by analyzing the incoming packet, no extra load is applied to other node devices that have already entered. For this reason, it is possible to reliably prevent the occurrence of problems such as adversely affecting the processing speed of other node devices that have already entered and the communication speed of the network.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing an entire network system including a node device according to the first embodiment of the present invention, and FIG. 2 is a functional block diagram showing a configuration of the node device according to the first embodiment.

  In the first embodiment, a plurality of node devices 1 (# 1 to # 4) are provided, and each node device 1 is individually connected with a control terminal 2 composed of a personal computer or the like. 1 are connected to each other in a ring shape via a network 3 to form a ring type network system. Here, a wired network such as an optical fiber or an electric wire is used as the network 3, but a wireless network may be used. Also, the number of node devices 1 connected to the network 3 is not limited to the number shown.

  Since each node device 1 (# 1 to # 4) has basically the same configuration, here, the details of the configuration will be described focusing on one node device 1 (# 1).

  The node device 1 includes a memory control unit 10, a local memory unit 11, a transfer control unit 12, a packet transmission / reception control unit 13, a packet observation function unit 14, an entry determination function unit 15, a network entry control unit 16, and a RAS unit 17. I have.

  The memory control unit 10 accesses the local memory unit 11 in accordance with a command from the terminal 2 and accesses the local memory unit 11 in accordance with the received packet.

  When the transfer control unit 12 generates a packet for transmission including its own node ID, transmission destination address, control data, and the like according to a command from the terminal 2, and the received packet is a valid packet Is to output the received packet to the memory control unit 10. In addition, when newly entering the network 3, a node ID is set by a command from the terminal 2, and information on the node ID is given to the transfer control unit 12 and the entry determination function unit 15.

  The packet transmission / reception control unit 13 transmits the packet generated by the transfer control unit 12 to the network 3, and if the transmission destination address included in the packet received from another node device 1 matches its own address, the packet transmission / reception control unit 13 The packet is captured and output to the transfer control unit 12.

  The packet observation function unit 14 extracts a node ID included in a packet received from another node device 1 over a predetermined period. The predetermined period in this case is set to be a period longer than the network update period in which at least all of the other node devices 1 that have already joined the network 3 are assumed to output packets.

  The entry determination function unit 15 determines whether or not the node ID of the other node device 1 extracted by the packet observation function unit 14 overlaps with the node ID of the own device and determines whether or not to enter the network 3. is there.

  The network entry control unit 16 maintains a so-called bypass state in which the received packet is transferred to another node device 1 until the entry determination function unit 15 determines that the entry is possible, and after the entry determination function unit 15 determines that the entry is possible. Cancels the bypass state, sends the received packet to the packet transmission / reception control unit 13, and sends the packet from the packet transmission / reception control unit 13 to another node device 1.

  The RAS unit 17 diagnoses and monitors the state of the node device 1 and forcibly shifts to a standby state in which a received packet is bypassed to another node device when a failure including a power interruption occurs. A switching signal for output is output.

  Here, when the node device 1 indicated by reference numbers # 1 to # 3 has already entered the network 3, and the node device 1 indicated by reference number # 4 is scheduled to newly enter the network 3, a new entry is made. The operation of the planned node device 1 (# 4) will be described with reference to the timing chart shown in FIG.

  The node device 1 (# 4) scheduled to newly enter is in a standby state in which a received packet is bypassed by another node device 1 when connected to the network 3. In this standby state, the packet observation function unit 14 extracts the node ID of the other node over a certain period (check period: t1) while bypassing the packet of the other node apparatus 1 already connected to the network 3. Since the check period t1 in this case is set in advance to be a period longer than the network update period in which at least all of the other node devices 1 that have already joined the network 3 are expected to output packets, the check period t1 When elapses, all node IDs of other node devices 1 (# 1 to # 3) that have already entered the network 3 have been extracted.

  Therefore, next, the entry determination function unit 15 checks whether or not the node ID of the other node device 1 extracted by the packet observation function unit 14 overlaps with the node ID of its own device, and determines whether or not to enter (determination). Period t2). Then, the determination result is given to the network entry control unit 16.

  The network entry control unit 16 cancels the standby state for bypassing the packet and determines whether to enter the packet transmission / reception control unit 13 when the entry determination function unit 15 determines that there is no duplication of the other node IDs. The packet transmission / reception permission is given to the user. As a result, the node device 1 scheduled to newly enter can transmit and receive packets and actually enter the network 3.

  On the other hand, when it is determined that entry is not possible, the network entry control unit 16 maintains a standby state in which the received packet is bypassed to another node device 1. In this standby state, if the node ID is subsequently changed by a command from the terminal 2 and the entry determination function unit 15 determines that entry is possible, the packet bypass state is canceled and packet transmission / reception becomes possible. Then, the network 3 is entered with the changed node ID.

  Note that after entering the network, the transfer control unit 12 generates a transmission packet including its own node ID, transmission destination address, control data, and the like in accordance with a command from the terminal 2. The packet transmission / reception control unit 13 transmits the packet generated by the transfer control unit 12 to the network 3. Further, since the packet transferred via the network 3 is input to the packet transmission / reception control unit 13 via the network entry control unit 16, the packet transmission / reception control unit 13 receives the packet received from the other node device 1. If the destination address included in the packet matches its own address, the packet is fetched and output to the transfer control unit 12. Since the transfer control unit 12 sends this packet information to the memory control unit 10, the memory control unit 10 accesses the local memory unit 11 in accordance with the received packet information. In addition, the memory control unit 10 accesses the local memory unit 11 in response to a command from the terminal 2.

  In addition, when a failure including a power interruption occurs, the RAS unit 17 outputs a switching signal to the standby state to the network entry control unit 16, and accordingly, the network entry control unit 16 sends the packet to another The node apparatus 1 is forcibly shifted to a standby state to be bypassed. As a result, occurrence of a cyclic failure of the packet is prevented.

  As described above, according to the node device 1 of the first embodiment, at the time of a new entry into the network 3, the other node device 1 that has already entered the network is not newly checked for duplicate node IDs, but is exclusively new. In the node device 1 to be entered, the node ID duplication check is performed by analyzing the packet sent from the other node device 1, so that an extra load is given to the other node device 1 that has already entered. There is no. For this reason, it is possible to reliably prevent the occurrence of problems such as adversely affecting the processing speed of other node devices 1 that have already entered and the communication speed of the network 3, and improving the reliability of the ring network system. it can.

Embodiment 2. FIG.
FIG. 4 is a functional block diagram showing the configuration of the node device 1 according to the second embodiment of the present invention, and the same reference numerals are given to the components corresponding to those in the first embodiment shown in FIG.

  In the first embodiment, when the node ID of the other node device 1 and the node ID of the own device overlap, the node device 1 scheduled to newly enter the node ID by the command from the terminal 2 thereafter Until the duplication is resolved after the change, the packet enters a standby state in which the packet is bypassed and cannot enter the network 3.

  Therefore, in the second embodiment, when a node ID selection function unit 18 is added to the configuration of the node device 1 of the first embodiment shown in FIG. A node ID that is not duplicated can be automatically selected, so that a node device 1 scheduled to newly enter can always enter the network 3 without human intervention.

That is, in the second embodiment, the node ID selection function unit 18 selects a node ID that does not overlap with the node IDs of other node devices 1 when the entry determination function unit 15 determines that entry is not possible. The transfer control unit 12 has a function of enabling entry of the determination result of the entry determination function unit 15 after selection of the node ID.
Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted here.

  In the node device 1 having the above configuration, an operation when one node device 1 (# 4 in this case) newly enters the network 3 will be described with reference to a timing chart shown in FIG.

  When the node device 1 (# 4) newly enters the network 3, the packet observation function unit 14 extracts the node ID from the packet of the other node device 1 over a predetermined period (observation period: t1), and then enters The determination function unit 15 determines whether or not the extracted node ID of the other node device 1 and the node ID of the own device are duplicated (determination period: t2), and the node IDs of the own and other devices are duplicated. When it is determined that entry into the network 3 is impossible, the operation until the packet received by the network entry control unit 16 is maintained in a standby state where it is bypassed by the other node device 1 is the case of the first embodiment. It is the same.

  Subsequently, in the second embodiment, when the entry determination function unit 15 determines that entry is not possible, the node ID selection function unit 18 does not overlap with the node IDs of other node devices 1 accordingly. The node ID is selected (selection period: t3), the node ID is given to the transfer control unit 12, and the determination result by the entry determination function unit 15 is allowed to enter after the node ID is selected.

  As a result, the network entry control unit 16 that has received the determination result indicating that entry is possible by the entry determination function unit 15 cancels the standby state for bypassing the packet, and gives the packet transmission / reception control unit 13 permission to transmit / receive the packet. As a result, the node device 1 scheduled to newly enter can transmit and receive packets and actually enter the network 3. Since other operations are the same as those in the first embodiment, detailed description thereof is omitted.

  As described above, according to the node device 1 of the second embodiment, even when node ID duplication is detected at the time of new entry, a new node ID without duplication is automatically set and enters the network 3. Therefore, in addition to the effect of the first embodiment, the duration of the standby state at the time of new entry can be shortened, and the trouble and extra labor of the node ID setting operation can be saved.

Embodiment 3 FIG.
FIG. 6 is a configuration diagram showing the entire ring network 3 including the node device 1 according to the third embodiment of the present invention, and FIG. 7 is a functional block diagram showing the configuration of the node device 1 according to the third embodiment. Components corresponding to those in the first and second embodiments shown in FIGS. 1, 2, and 4 are denoted by the same reference numerals.

  In the case of the above-described first and second embodiments, when a plurality of node devices 1 enter the network 3 at the same time, a node ID duplication check cannot be performed between newly entered node devices 1. 1 may enter the network 3 with the same node ID. In particular, when a new ring-type network system is constructed, all node devices are connected to the network 3 at the same time, so there is a high possibility that node IDs will be duplicated.

  Therefore, in order to avoid such a situation, in the third embodiment, a standby time setting function unit 19 is further added to the node device 1 having the configuration of the second embodiment shown in FIG. When a plurality of node devices 1 enter the network 3 at the same time, it is possible to prevent the plurality of node devices 1 from entering with the same node ID by individually setting the standby time until entry for each node device 1 scheduled to newly enter. It is a thing.

That is, in the third embodiment, the standby time setting function unit 19 sets the standby time Twt unique to the own device for each newly joining node device 1, and the packet is received when the standby time Twt has elapsed. The packet extraction operation by the observation function unit 14 is started. Here, since each node device 1 is assigned in advance with a device-specific MAC address for device identification, the waiting time Twt is set, for example, as Twt = (lower-order predetermined bits of the MAC address) × 10 mS. In the third embodiment, as the numbers # 1 to # 5 of the node device 1 are increased, the standby times Twt1 to twt5 are gradually increased.
Since other configurations are the same as those in the second embodiment, detailed description thereof is omitted here.

  In the node device 1 having the above configuration, in this example, the operation when all the node devices 1 (here, five units # 1 to # 5) newly enter the network 3 at the same time is shown in the flowchart shown in FIG. This will be described with reference to the timing chart shown in FIG.

  Each node device 1 to be newly entered first enters a standby state when it is connected to the network 3 (S31). In this standby state, the received packet is bypassed to the other node device 1, and the packet extraction operation by the packet observation function unit 14 is stopped.

  Then, when a predetermined standby time Twt1 to Twt5 (= lower predetermined bit of the MAC address × 10 mS) has elapsed in each node device 1 (# 1 to # 5) (S32), the standby time setting function unit 19 at that time The packet extraction operation by the observation function unit 14 is started (check period: t1) (S33). Next, the entry determination function unit 15 determines whether or not the extracted node ID of the other node device 1 and the node ID of the own device overlap (determination period: t2) (S34).

  At this time, when it is determined that there is no duplication of the node IDs of the other devices, the network entry control unit 16 releases the standby state for bypassing the packet and the packet transmission / reception control unit 13 accordingly. Since the packet transmission / reception permission is given, the node device 1 that is scheduled to newly enter the network can transmit and receive packets and enter the network 3 with the node ID (S35).

On the other hand, when it is determined in S34 that the node IDs of the other devices are duplicated, the node ID selection function unit 18 selects a node ID that does not overlap with the node IDs of the other node devices 1 (selection period). : T3) (S36), the node ID is given to the transfer control unit 12, and after the selection of the node ID, the determination result by the entry determination function unit 15 can be entered. Packets can be transmitted and received, and the network 3 is entered with the changed node ID.
Since other operations are the same as those in the first and second embodiments, detailed description is omitted here.

  As described above, according to the node device 1 of the third embodiment, in addition to the effects of the first and second embodiments, when a plurality of node devices 1 enter the network 3 at the same time, the node device scheduled to be newly entered Since the waiting time until entry is individually set for each, it is possible to reliably prevent a plurality of node devices 1 from entering at the same time with the same node ID, and further improve the reliability of the ring network 3 be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the whole ring type network system provided with the node apparatus in Embodiment 1 of this invention. It is a functional block diagram which shows the structure of the node apparatus in Embodiment 1 of this invention. In Embodiment 1 of this invention, it is a timing chart with which it uses for description when one node apparatus newly enters a network. It is a functional block diagram which shows the structure of the node apparatus in Embodiment 2 of this invention. In Embodiment 2 of this invention, it is a timing chart with which it uses for description when one node apparatus newly enters a network. It is a block diagram which shows the whole ring type network system provided with the node apparatus in Embodiment 3 of this invention. It is a functional block diagram which shows the structure of the node apparatus in Embodiment 3 of this invention. It is a flowchart which shows the flow of the process accompanying the new entry of the node apparatus in Embodiment 3 of this invention. In Embodiment 3 of this invention, it is a timing chart with which it uses for description when a some node apparatus newly enters a network simultaneously. In prior art, it is explanatory drawing when one node apparatus newly enters a network.

Explanation of symbols

1 node device, 12 transfer control unit, 13 packet transmission / reception control unit,
14 packet observation function unit, 15 entry determination function unit, 16 network entry control unit,
18 Node ID selection function part, 19 Standby time setting function part.

Claims (4)

A node device for configuring a network system connected to each other in a ring shape via a network,
A transfer control unit that generates a packet for transmission including at least its own node ID, transmission destination address, and control data;
A packet transmission / reception control unit for transmitting the packet generated by the transfer control unit to the network and capturing the packet if the destination address included in the packet received from another node device matches its own address; ,
A packet observation function unit that extracts a node ID included in a packet received from another node device over a predetermined period;
An entry determination function unit that checks whether or not the node ID of the other node device extracted by the packet observation function unit and the node ID of the own device overlap, and determines whether or not to enter the network;
Until this entry determination function unit determines that entry is possible, the received packet is sent to another node device, and after this entry determination function unit determines that entry is possible, the received packet is sent to the packet transmission / reception control unit. A network entry control unit that sends a packet from the packet transmission / reception control unit to another node device,
A node device comprising: The predetermined period for extracting the node ID by the packet observation function unit is set to be a period longer than the network update period in which it is assumed that at least all other node devices that have already joined the network output packets. The node device according to claim 1. When it is determined that entry is impossible by the entry determination function unit, a node ID that does not overlap with the node IDs of other node devices is selected and given to the transfer control unit, and the entry determination is performed after this node ID is selected. The node device according to claim 1, further comprising a node ID selection function unit that enables entry of the determination result of the function unit. The apparatus further comprises a standby time setting function unit for setting a standby time unique to the own device at the time of new entry, and the packet observation function unit starts extracting packets after the standby time has elapsed. The node device according to any one of claims 1 to 3.

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