JP2011193223A - Network connection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: a terminal in a subnet which does not respond to an ICMP echo request cannot be detected and communication recovery of the terminal is difficult in the conventional network connection device. <P>SOLUTION: The network connection device includes a self-IP address and a subnet mask, and is constituted so as to generate object IP addresses for the respective terminals which can exist in the subnet based on the equipped IP address and the equipped subnet mask, to transmit an ARP request for asking MAC addresses for the respective generated object IP addresses to the subnet, to receive an ARP reply to be transmitted from the subnet, and to check a source IP address and a source MAC address from the received ARP reply. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a network system provided with a plurality of network connection devices for redundantly connecting a backbone network and a subnet, and in particular, promptly recovers communication between terminals when the subnet is divided. The present invention relates to a network connection device having a function of

  As a communication protocol, IP (Internet Protocol) is widely used. In IP, a connection device called a router is connected and installed between subnets, and relays IP packets to enable communication between arbitrary subnets and thus between arbitrary devices. For the subnet, the router is the gateway to the external network, so if this fails, the connection to the external network is broken. In a highly reliable network system, a method is adopted in which a plurality of routers are connected to and installed in a subnet for redundancy. In a redundant subnet having a plurality of routers, it is necessary to select a router to be used when an arbitrary terminal device is connected to an external network. For this purpose, a redundancy protocol such as VRRP (Virtual Router Redundancy Protocol, Internet Engineering Task Force: IETF RFC2338) is used, and a terminal device can select a router as a relay destination.

  However, when the switching hub fails, the ARP request packet from an arbitrary terminal device to another terminal device cannot be conducted, and communication cannot be performed. Further, even when an entry of another terminal device is stored in the ARP table of an arbitrary terminal device, the arbitrary terminal device sets the MAC address of the other terminal device as the destination MAC address, and the other terminal device The packet is not relayed due to a failure of the switching hub, and communication is interrupted. When such a subnet is divided, normal communication cannot be performed. As a countermeasure, when a subnet break is detected, the combination of the current IP address and MAC address of all terminal devices in the divided subnet is learned (confirmed / stored), and is divided via the backbone network. A method of exchanging information between a router on the opposite side constituting a wide area detour and a terminal device to restore communication between divided subnets is known (for example, see Patent Document 1).

JP 2002-232448 A

  In a conventional network connection device, learning of combinations of IP addresses and MAC addresses of all terminal devices in the divided subnet is sent, and an ICMP (Internet Control Message Protocol) eco-request is transmitted to the broadcast address. For example, a terminal device that does not respond to an ICMP eco-request or a terminal device that does not respond to an ICMP eco-request addressed to a broadcast address can be detected. Therefore, there is a problem that the communication of the terminal device that does not respond cannot be restored.

  The present invention solves the problems as described above, and obtains a device capable of detecting the presence of these terminal devices and enabling communication recovery even when there are terminal devices that do not respond to the ICMP Eco-Request. Objective.

  The network connection device of the present invention monitors the continuity with other network connection devices connected to a specific subnet, and recognizes that each terminal device in the subnet is disconnected. A network connection device comprising: a status confirmation unit that instructs to collect connection device information of each terminal device; and a connection device information collection unit that collects connection device information of all terminal devices on the subnet. The network connection device includes: an IP address information section that records its own IP address and subnet mask; and an object for each terminal device that may exist in the specific subnet based on the own IP address and subnet mask. A request generator that generates an IP address, and an ARP request that inquires about the MAC address of the target IP address generated by the request generator. A request transmission unit that transmits a request to the specific subnet, a reception unit that receives an ARP reply transmitted from the specific subnet, a source IP address and a source stored in the ARP reply from the received ARP reply. A learning unit for confirming a MAC address;

  The network connection apparatus configured as described above may be present in the specific subnet based on the IP address information section in which the own IP address and subnet mask are recorded, and the own IP address and subnet mask. A request generation unit that generates a target IP address for each terminal device, a request transmission unit that transmits an ARP request asking for the MAC address of the target IP address generated by the request generation unit to the specific subnet, and the specific subnet And a learning unit for checking the source IP address and the source MAC address stored in the ARP reply from the received ARP reply. Even if there is a terminal device that does not respond to the request, Detecting the presence of these terminals, it is possible to communicate recovery.

It is a block diagram of the network connection apparatus of Embodiment 1 of this invention. It is a flowchart of the request generation part of Embodiment 1 of this invention. It is a block diagram of the network connection apparatus of Embodiment 2 of this invention. It is a format of the search IP address registration table of Embodiment 2 of this invention. It is a flowchart of the request generation part of Embodiment 2 of this invention. It is a flowchart of the request generation part of Embodiment 3 of this invention. It is a block diagram of the network connection apparatus of Embodiment 4 of this invention. It is the format of the search IP address map table of Embodiment 4 of this invention. It is a flowchart of the request generation part of Embodiment 4 of this invention.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a network connection apparatus connected to a network according to the first embodiment of the present invention, and FIG. 2 is a flowchart of a request generation unit. In addition, the same code | symbol in a figure has shown the same or an equivalent part.

  As shown in FIG. 1, a network connection device 1000 is connected to a backbone network 2000 and a subnet 3000 (a specific subnet). When the network connection device 1000 recognizes that each terminal device (not shown) in the subnet is divided, the network connection device 1000 collects connection device information of the terminal device connected to the own device (network connection device 1000). Connected device information collecting unit 100, IP address information unit 200 storing its own device IP address M01 and subnet mask S01, and other networks connected to a specific subnet via backbone network 2000 and subnet 3000 A state confirmation unit 300 that monitors a conduction state with a network connection device, a recording unit 400 that records information on a connection device that can confirm and learn ARP replies from each terminal device in a specific subnet, which will be described in detail later, and an IP It is composed of an ARP table 500 in which addresses and MAC addresses are associated. The state confirmation unit 300, the recording unit 400, and the ARP table 500 have functions similar to those described in Japanese Patent Application Laid-Open No. 2002-232448.

  The connected device information collection unit 100 includes a request generation unit 101 that generates an ARP request, a request transmission unit 102 that transmits an ARP request generated by the request generation unit 101, and an ARP request or ARP from any terminal device via a subnet. A receiving unit 103 that receives a reply and extracts a target protocol address from the received information, and a learning unit 104 that learns a combination of a source IP address and a source MAC address from an ARP reply received from a subnet. It is configured. The learning result of the learning unit 104 is recorded in the recording unit 400 and the ARP table 500. The operation of network connection apparatus 1000 according to the first embodiment of the present invention when state confirmation unit 300 recognizes that each terminal apparatus in a specific subnet has been divided will be described below.

  As shown in the flow chart of the request generation unit in FIG. 2, the request generation unit 101 according to the first embodiment of the present invention receives the IP address M01 and the subnet mask S01 from its own (own device) from the IP address information unit 200. Is acquired (step F01).

  By performing a bit AND operation on the acquired IP address M01 and subnet mask S01, the network address N01 of the subnet is taken out. As will be described in detail later, this step is a base of the target IP address for transmitting an ARP request later (step F02).

  Bit inversion of the subnet mask S01 is performed, and 1 is subtracted to take out the host part H01 which is the host address in the IP address. Since the maximum value of the host unit is normally used as a broadcast address, it is not assigned to the terminal device. Therefore, in order to exclude this, -1 is set (step F03).

  In order to acquire (generate) all IP addresses that can be defined within the subnet, the host part H01 in the IP address is sequentially changed (decremented by 1 in binary), and combined with the network address N01 as the target IP address. Start the loop process. In the loop, first, it is confirmed whether or not the host unit H01 is 0 (step F04).

  If the host unit H01 is 0, the process is terminated (step F08).

  If the host unit H01 is not 0, the network address N01 and the bit OR of the host unit H01 are taken to generate the target IP address necessary for the ARP request (step F05).

  This target IP address is passed to the request transmission unit 102 (step F06).

  The host unit H01 is decremented by 1, and the process returns to the determination of F04. Note that if the host unit H01 becomes 0 at this time, the processing is terminated by the determination in step F04, so that an IP address with the host unit H01 of 0 is not a target IP address. This is a countermeasure against a terminal device (an old IP device such as an early workstation where IP has begun to be used) that uses the host unit H01 as 0 as a broadcast address (step F07).

  The request transmission unit 102 to which the target IP address is passed transmits an ARP request (broadcast) for inquiring about the MAC address of the passed target IP address to the subnet 3000.

  When a terminal device having the target IP address exists in the subnet 3000, the corresponding terminal device returns an ARP reply storing its own MAC address. The receiving unit 103 receives this and passes it to the learning unit 104. The learning unit 104 confirms the source IP address and source MAC address of the ARP reply, records the confirmed source IP address and source MAC address as a pair in the recording unit 400, and Recorded in Bull 500.

  If the terminal device having the target IP address does not exist in the subnet in a connectable state, the ARP reply is not returned. Therefore, the learning unit 104 does not learn the source IP address and the source MAC address of the terminal device having the IP address that cannot be connected, and may be recorded in the recording unit 400 and the ARP table 500. Absent.

  As described above, the network connection apparatus 1000 according to the first embodiment of the present invention exists in a state where communication is possible within a specific subnet 3000, and the source IP address and source of the terminal apparatus using IP. The MAC address can be learned. Even when the terminal device does not respond to the ICMP echo-request, it is necessary to respond to the ARP request for IP communication, and the existence of the terminal device can be reliably learned.

Embodiment 2. FIG.
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a block diagram of a network connection apparatus according to the second embodiment of the present invention, FIG. 4 is a format of a search IP address registration table, and FIG. 5 is a flowchart of a request generation unit. . 3 to 5, the same or corresponding parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  As shown in FIG. 3, a network connection apparatus 1000 according to the second embodiment includes the search IP address registration table 105 in the network connection apparatus 1000 according to the first embodiment. As shown in FIG. 4, in the search IP address registration table 105, search target IP addresses 1 to N which are IP addresses to be detected with priority are registered in advance by the administrator. In the table structure of the search IP address registration table 105, a plurality of data of the same type such as names and IP addresses are registered. Each of these registered items is called an entry. The method of setting the search target IP addresses 1 to N in advance in the search IP address registration table is performed by using the setting function of the network connection device, and the details thereof are omitted.

  The request generation unit 101 acquires a search target IP address to be passed to the request transmission unit 102 from the search IP address registration table 105, and then generates a target IP address by the IP address generation method described in the first embodiment. The operation of network connection apparatus 1000 according to the second embodiment of the present invention will be described below. Note that similar operations described in Embodiment 1 are omitted.

  As shown in the flowchart of FIG. 5, the request generation unit 101 according to the second embodiment of the present invention searches for the first entry registered at the beginning (first) of the search IP address registration table 105, Move on to the next step. The method of searching for the head entry has, for example, the number of registered entries indicating how many entries are registered in order from the head entry as a table structure. Then, the software determines that registration has been completed for the number of registered entries from the top entry (step F11).

  If the search target IP address is registered in the first entry, the search target IP address is passed to the next step. If not registered, the process proceeds to step F01. As a method for determining registration, for example, since the software knows the number of registered entries, if the entry number to be checked is equal to or smaller than the number of registered entries, it is determined that the target entry exists. In this step, nothing may be registered in the search IP address registration table 105 (when the user does not set an IP address that the user wants to detect preferentially). This is a process for determining this because there is a case where the entry is not registered even if the head entry of the table 105 is seen (step F12).

  The search target IP address obtained from step F12 is passed to the request transmission unit 102 as the target IP address, and the process proceeds to the next step (step F13).

  The next entry in the search IP address registration table 105 is searched. If there is a next entry, the process returns to step F12. Since all the search target IP addresses 1 to N registered in the search IP address registration table 105 are passed to the request transmission unit 102 in this way, there are no target entries, and thus the returned step F12 The process moves from step F01 to step F01. (Step F14).

  Since the processing from step F01 to step F08 is performed in the same steps as the flow of the request generation unit described in the first embodiment, the description thereof is omitted.

  As described above, the network connection device 1000 according to the second embodiment of the present invention may preferentially detect the terminal device specified by the user when detecting the terminal device existing in the subnet. it can. Therefore, it is possible to detect a terminal device that should be detected with priority earlier than a terminal device that does not have priority.

Embodiment 3 FIG.
Hereinafter, the third embodiment of the present invention will be described in detail with reference to the drawings. FIG. 6 is a flowchart of the request generation unit according to the third embodiment of the present invention. In FIG. 6, the same or corresponding parts as those in FIGS. 1 to 5 are given the same reference numerals. The operation of the network connection apparatus according to the third embodiment of the present invention is described below.

  As shown in FIG. 6, the request generation unit 101 of the network connection apparatus 1000 according to the third embodiment is newly executed between step F05 and step F06 of the request generation unit 101 of the network connection apparatus 1000 according to the second embodiment. Step F15 is added, and the other steps are the same as those in the request generation unit 101 of the second embodiment.

  After obtaining the target IP address in step F05, the request generation unit 101 searches the search IP address registration table 105 to confirm whether the target IP address is registered in the search IP address registration table 105. If this target IP address is not registered in the search IP address registration table 105, the target IP address is passed to step F06. On the other hand, if it is registered in the search IP address registration table 105, since this target IP address has already been passed to the request transmission unit 102, it is passed to step F07 to avoid this duplication (step F15).

  Since the processing of each step other than step F15 is performed in the same steps as the flow of the request generation unit 101 described in the second embodiment, the description thereof is omitted.

  As described above, the network connection apparatus 1000 according to the third embodiment of the present invention does not transmit the target IP address in duplicate to the ARP request, so that the network bandwidth can be effectively used and other terminals can be used. It has a special effect that the device can be detected quickly.

Embodiment 4 FIG.
Hereinafter, the fourth embodiment of the present invention will be described in detail with reference to the drawings. 7 is a block diagram of a network connection apparatus according to the third embodiment of the present invention, FIG. 8 is a format of a search IP address map table, and FIG. 9 is a flow chart of a request generation unit. . 7 to 9, the same or corresponding parts as those in FIGS. 1 to 6 are denoted by the same reference numerals.

  When a subnet is divided at a plurality of short-distance locations, it tends to be difficult to access a network connection device near the division location from a terminal device far from the division location. In other words, there is a high possibility that the terminal device and the network connection device that are close to the parting location can be accessed relatively.

  As shown in FIG. 7, the request generation unit of the network connection device of the third embodiment performs the search IP address registration table 105 and the step 11 of the request generation unit 101 of the network connection device of the second embodiment. The search IP address map table 106 and the request generation unit 101 are replaced with step F16, and other configurations are the same as those in the second embodiment.

  The search IP address map table 106 is a table in which the IP addresses of the terminal devices existing in the subnet are registered in order from the nearest device. Note that the method of setting the search target IP addresses 1 to N in advance in the search IP address map table is performed by using the setting function of the network connection device, and the details thereof are omitted. The operation of network connection apparatus 1000 according to the fourth embodiment of the present invention will be described below.

  The request generation unit 101 acquires an IP address from the search IP address map table 106 as a target IP address to be passed to the request transmission unit 102.

  As shown in FIG. 9, the request generation unit 101 of the network connection apparatus of the fourth embodiment searches for the head entry of the search IP address map table 106 (step F16).

  If the search target IP address is registered in the first entry, the search target IP address is passed to step F13. If the search target IP address is not registered in the first entry, the process proceeds to step F12.

  Since the processing of each step other than step F16 is performed in the same step as the flow of the request generation unit described in the second embodiment, the description thereof is omitted.

  As described above, the network connection apparatus 1000 according to the fourth embodiment of the present invention searches for a terminal apparatus that has a high possibility of being accessed before detecting a terminal apparatus existing in the subnet, and as a result, This has the special effect of speeding up recovery of the recoverable terminal device.

100 connection device information collection unit, 101 request generation unit,
102 request sending unit, 103 receiving unit,
104 learning unit 105 search IP address registration table 106 search IP address map table
200 IP address information section,
300 status confirmation unit, 1000 network connection device,
3000 subnets

Claims (4)

When the state of continuity with other network connection devices connected to a specific subnet is monitored and the status of each terminal device in the subnet is recognized, the connection device information of each terminal device is displayed. A status confirmation unit that instructs to collect,
In a network connection device comprising a connection device information collection unit for collecting connection device information of all terminal devices on the subnet,
The network connection device includes an IP address information section that records its own IP address and subnet mask,
A request generating unit that generates a target IP address for each terminal device that may exist in the specific subnet based on the self IP address and a subnet mask;
A request transmission unit that transmits an ARP request asking for the MAC address of the target IP address generated by the request generation unit to the specific subnet;
A receiving unit for receiving an ARP reply transmitted from the specific subnet;
A network connection device comprising: a learning unit for confirming a source IP address and a source MAC address stored in the ARP reply from the received ARP reply. The network connection device according to claim 1,
A search IP address registration table in which each search target IP address of each terminal device detected by the request generation unit is registered in advance;
A network connection device comprising: a request transmission unit that preferentially transmits an ARP request with respect to the search target IP address. The network connection device according to claim 1,
A search IP address map table in which a search target IP address is registered in advance so that the request generation unit preferentially detects terminal devices located in the order from the installation location of the network connection device itself;
A network connection device comprising: a request transmission unit that preferentially transmits an ARP request with respect to the search target IP address. The network connection device according to claim 2 or 3, wherein
The network connection apparatus, wherein the request generation unit is configured not to generate a target IP address for the registered search target IP address.

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