JP5497535B2 - Communication device, failure detection method, failure detection program, communication system, and communication method - Google Patents

Description

  The present invention relates to a failure detection function and a communication device switching function in a redundant network. In particular, the present invention relates to a failure detection function and a communication device switching function using HSRP (Hot Standby Routing Protocol) or VRRP (Virtual Router Redundancy Protocol) in a so-called star network, and an IP-SLA (Internet Protocol-Service Level Agreement). ) Is used in conjunction with the network monitoring function.

  With the recent widespread use of network environments, redundancy has been given to systems that constitute networks for the purpose of increasing network availability.

  For example, FIG. 7 shows a configuration example of a so-called star network. FIG. 7 is a diagram illustrating a configuration example of a so-called star network. As shown in FIG. 7, the star network 10 includes an upper router 11, intermediate switches 12A to 12D, and lower routers 13A to 13D. In the star network 10, intermediate switches 12 </ b> A to 12 </ b> D are connected under the upper router 11 as shown in FIG. 7.

  Further, in the star network 10, as shown in FIG. 7, the lower router 13A is connected to the intermediate switch 12A, the lower router 13B is connected to the intermediate switch 12B, and the lower router 13C is connected to the intermediate switch 12C. A lower router 13D is connected to the switch 12D. As shown in FIG. 7, the terminal 15A is connected to the lower router 13A via the switch 14A, the terminal 15B is connected to the lower router 13B via the switch 14B, and the terminal 15B is connected to the lower router 13C via the switch 14C. The terminal 15C is connected to the lower router 13D via the switch 14D.

  For example, FIG. 8 shows a redundant configuration example of the star network shown in FIG. 7 described above. FIG. 8 is a diagram showing a redundant configuration example of the star network shown in FIG. 7 described above. FIG. 8 shows a redundant configuration in which the star network 10 shown in FIG. 7 is “Active” and the star network 201 having the same configuration as the star network 10 is “Standby”.

  Hereinafter, for example, it is assumed that the HSRP defined in RFC (Request For Comment) 2281 established by the IETF (The Internet Engineering Task Force) has been set for the star network having the redundant configuration shown in FIG. A failure detection method using HSRP will be described. Note that HSRP defined in RFC (Request For Comment) 2281 and VRRP defined in RFC (Request For Comment) 3768 basically realize failure detection by the same operation.

  For example, a router with a higher priority value set for each of the plurality of routers shown in FIG. 8 plays a role as an active router, and a router with a lower priority value plays a role as a standby router. When a failure occurs in the Active router that performs the actual operation, the Standby router executes the actual operation related to packet communication or the like instead of the Active router.

  Between the active router and the standby router shown in FIG. 8, a life / death confirmation packet for notifying each other's normality and priority value, a so-called “Hello packet” is exchanged. When a standby router cannot receive a “Hello packet” from an active router, it determines that a failure has occurred in the active router, and performs an actual operation related to packet communication on behalf of the active router. Execute.

  FIG. 9 is a diagram in which one base in the redundant configuration is extracted from the redundant star network shown in FIG. As shown in FIG. 9, an HSRP 30 is set between the active upper router 11 and the standby upper router 21. Also, as shown in FIG. 9, HSRPs 31 and 32 are set between the Active lower router 13A and the Standby lower router 23A. The Active subordinate router 13A and the Standby subordinate router 23A exchange the “Hello packet” via the Active intermediate switch 12A and the Standby intermediate switch 22A using the HSRP 31 function. Also, the Active lower router 13A and the Standby lower router 23A monitor the outside of the network by using the HSRP 32 function.

  As shown in FIG. 9, for example, when a failure occurs in a cable connecting the active intermediate switch 12A and the standby intermediate switch 22A, for example, the lower router 13A accommodated in the active star network 10 The “Hello packet” cannot be exchanged with the lower router 23A accommodated in the Starby network 20 of the Standby system. In such a case, actually, even if no failure has occurred in the active lower router 13A, the lower router 23A operates by switching from the standby system to the active system. On the other hand, the lower router 13A that was originally an active system does not have a failure, and thus continues to operate as an active system.

  Thus, when a situation occurs in which a plurality of active routers exist in a redundant star network, the communication performance of terminals connected to the network is adversely affected. Specifically, when a router is switched due to the occurrence of a failure in a star network with a redundant configuration, a notification (notifying the router change to a terminal connected to the failed router ( Gratuitous ARP) is sent. For this reason, when a plurality of active routers are connected to a terminal, there is a problem that an ARP (Address Resolution Protocol) table of the terminal is destroyed.

  Thus, in a redundant star network, an attempt has been made to use HSRP and VRRP together with IP-SLA which is one of network monitoring functions. The IP-SLA exchanges a monitoring packet for detecting a communication failure in the network caused by a failure of a network device or a cable disconnection, so-called “monitoring icmp (Internet Control Message Protocol) packet” in the network. This is a function to detect communication failures in the network.

  FIG. 10 is a diagram illustrating a configuration example when HSRP and IP-SLA are used together in the star network having the redundant configuration illustrated in FIG. As shown in FIG. 10, for example, with respect to the active lower router 13A, the route of the intermediate switch 12A → the upper router 11 → the intermediate switches 12B, 12C, 12D is “monitored” by all of the lower routers 13B, 13C, 13D. Set to send "icmp packet".

  Similarly, the lower router 13B is set to send the “monitor icmp packet” to all of the lower routers 13A, 13C, and 13D through the route of the intermediate switch 12B → the upper router 11 → the intermediate switches 12A, 12C, and 12D. . Similarly, the lower router 13C is set to send the “monitor icmp packet” to all of the lower routers 13A, 13B, and 13D through the route of the intermediate switch 12C → the upper router 11 → the intermediate switches 12A, 12B, and 12D. . Similarly, the lower router 13D is set to send the “monitor icmp packet” to all of the lower routers 13A, 13B, and 13C through the route of the intermediate switch 12D → the upper router 11 → the intermediate switches 12A, 12B, and 12C. . In this way, it is possible to specify a location where the “monitoring icmp packet” can no longer be exchanged between lower routers. For this reason, it is possible to detect a failure occurring anywhere in the network.

  In this way, by using HSRP and IP-SLA together in a redundant star network, it is possible to prevent a standby router from being switched to an active router due to a cable failure. As a result, the occurrence of a situation in which the ARP table of the terminal is destroyed by connecting a plurality of Active routers to the terminal can be avoided, and the communication performance of the terminal connected to the network can be adversely affected. There is no.

  Further, the above-described problem occurs due to the exchange of packets via the intermediate switch. Therefore, a configuration in which no intermediate switch is provided in the star network is also conceivable.

  FIG. 11 is a diagram illustrating a configuration example of a redundant network without an intermediate switch. As shown in FIG. 11, in the case where the intermediate network is not provided in the redundant configuration network, the “Hello packet” needs to be exchanged in the same subnet, so the HSRP setting location is in the Active network 40. It is restricted between the lower router 43 accommodated and the lower router 53 accommodated in the Standby network 50. Further, the HSRP 80 cannot detect a communication failure that has occurred between the upper router 41 and the HUB 42.

  Therefore, a method of applying IP-SLA to a redundant network without an intermediate switch is conceivable. For example, the destination of the “monitoring icmp (Internet Control Message Protocol) packet” of the IP-SLA is set in the upper router 41. As described above, even in a redundant network without an intermediate switch, communication failure between the upper router 41 and the HUB 42 can be detected by applying the IP-SLA.

JP 2007-189321 A

  By the way, in the technology (see FIG. 10) using HSRP and IP-SLA together in the above-described redundant star network, “monitoring icmp packet” is sent from each lower router to all lower routers other than itself. Settings are made. For this reason, when the number of lower routers accommodated in the network increases, the number of “monitoring icmp packets” that must be processed in the active star network increases. As a result, much of the processing capability of the active-type star network system is spent on the processing of the “monitoring icmp packet”. Therefore, the normal data communication packet other than the “monitoring icmp packet” is delayed or discarded. This causes a problem that the communication quality deteriorates.

  It should be noted that a decrease in communication quality due to an increase in the processing load of the “monitoring icmp packet” is also a problem in the technique (see FIG. 11) in which the IP-SLA is applied in a redundant network without an intermediate switch described above. .

  The present invention has been made in view of the above, and can reduce the number of packets for detecting a failure in a network and maintain communication quality, a failure detection method, a failure detection program, An object is to provide a communication system and a communication method.

  In order to solve the above-described problems and achieve the object, the present invention is a communication device accommodated on the operational network side constituting a redundant network, and is accommodated on the operational network side. A packet transmission unit that transmits a failure detection packet for detecting a failure in the network to a specific communication device set in advance from among the communication devices, and a failure detection packet transmitted by the packet transmission unit And an interface stopping unit that stops a network interface when a corresponding response is not received from the specific communication device.

  ADVANTAGE OF THE INVENTION According to this invention, the number of packets for detecting the failure in a network can be reduced and communication quality can be hold | maintained.

FIG. 1 is a diagram illustrating the configuration of the communication system according to the first embodiment. FIG. 2 is a diagram illustrating the configuration of the lower router 130A according to the first embodiment. FIG. 3 is a diagram illustrating an example of information stored in the failure detection packet transmission reference table 131A according to the first embodiment. FIG. 4 is a diagram for explaining an overview of switching of the network system according to the first embodiment. FIG. 5 is a diagram illustrating a flow of processing by the lower router according to the first embodiment. FIG. 6 is a diagram illustrating a computer that executes a failure detection program. FIG. 7 is a diagram illustrating a configuration example of a so-called star network. FIG. 8 is a diagram showing a redundant configuration example of the star network shown in FIG. 7 described above. FIG. 9 is a diagram in which one base in the redundant configuration is extracted from the redundant star network shown in FIG. FIG. 10 is a diagram illustrating a configuration example when HSRP and IP-SLA are used together in the star network having the redundant configuration illustrated in FIG. FIG. 11 is a diagram illustrating a configuration example of a redundant network without an intermediate switch.

  Hereinafter, an embodiment of a communication device, a failure detection method, a failure detection program, a communication system, and a communication method disclosed in the present application will be described in detail with reference to the drawings.

  In Example 1 described below, Example 1 will be described as an embodiment of a communication system according to the present invention. The invention disclosed in the present application is not limited by the following Example 1.

  The communication system according to the first embodiment is made redundant with an active network in which a plurality of communication devices are accommodated and a standby network that backs up the active network when a failure occurs in the active network. Have a network. The communication device accommodated in the active network detects a failure in the network with respect to a specific communication device set in advance from other communication devices accommodated in the active network. The network interface is stopped when a packet is transmitted and a response corresponding to the transmitted failure detection packet is not received from a specific communication device.

[Configuration of Communication System (Example 1)]
FIG. 1 is a diagram illustrating the configuration of the communication system according to the first embodiment. As illustrated in FIG. 1, the communication system according to the first embodiment includes an active star network 100 and a standby star network 200. The active star network 100 corresponds to an operational network in which actual operation such as packet communication is performed. The stand-by star network 200 corresponds to a standby network that functions as a backup when a failure occurs in the active star network 100.

  As shown in FIG. 1, the active star network 100 includes an upper router 110, intermediate switches 120A to 120D, and lower routers 130A to 130D. The upper router 110 is connected to the intermediate switches 120 </ b> A to 120 </ b> D through the cable 300 so as to be communicable.

  The intermediate switch 120A is connected via the cable 300 in a state where it can communicate with the lower router 130A. The intermediate switch 120B is connected via the cable 300 in a state where it can communicate with the lower router 130B. The intermediate switch 120C is connected via the cable 300 in a state where it can communicate with the lower router 130C. The intermediate switch 120D is connected via the cable 300 in a state where it can communicate with the lower router 130D.

  The lower router 130A is connected to the switch 140A through the cable 300 in a communicable state. The lower router 130B is connected to the switch 140B through the cable 300 in a communicable state. The lower router 130 </ b> C is connected via the cable 300 in a state where it can communicate with the switch 140 </ b> C. The lower router 130D is connected via the cable 300 in a state where it can communicate with the switch 140D.

  The switch 140A is connected to the terminal 150A through the cable 300 so as to be able to communicate with the terminal 150A. The switch 140B is connected to the terminal 150B through the cable 300 in a communicable state. The switch 140C is connected to the terminal 150C through the cable 300 so as to be able to communicate with the terminal 150C. The switch 140D is connected to the terminal 150D through the cable 300 so as to be able to communicate with the terminal 150D.

  The intermediate switches 120A to 120D and the switches 140A to 140D have general functions as network switches such as a packet switching function. The terminals 150A to 150D correspond to, for example, personal computers and servers, and have general functions that the personal computers and servers have.

  The stand-by star network 200 has the same configuration as the active star network 100 as shown in FIG. That is, the standby star network 200 includes an upper router 210, intermediate switches 220A to 220D, and lower routers 230A to 230D. The upper router 210 is connected to the intermediate switches 220 </ b> A to 220 </ b> D via the cable 300 so as to be communicable.

  The intermediate switch 220A is connected via the cable 300 in a state where it can communicate with the lower router 230A. The intermediate switch 220B is connected via the cable 300 in a state where it can communicate with the lower router 230B. The intermediate switch 220C is connected via the cable 300 in a state where it can communicate with the lower router 230C. The intermediate switch 220D is connected via the cable 300 so as to be communicable with the lower router 230D.

  As shown in FIG. 1, HSRP is set between the lower router 130 </ b> A accommodated in the active star network 100 and the lower router 230 </ b> A accommodated in the standby star network 200. The lower router 230A serves as a backup router for the lower router 130A. Further, as shown in FIG. 1, HSRP is set between the lower router 130B accommodated in the active star network 100 and the lower router 230B accommodated in the standby star network 200. The lower router 230B serves as a backup router for the lower router 130B.

  Also, as shown in FIG. 1, HSRP is set between the lower router 130C accommodated in the active star network 100 and the lower router 230C accommodated in the standby star network 200. The lower router 230C serves as a backup router for the lower router 130C. Also, as shown in FIG. 1, HSRP is set between the lower router 130D accommodated in the active star network 100 and the lower router 230D accommodated in the standby star network 200. The lower router 230D serves as a backup router for the lower router 130D.

[Configuration of Subordinate Router (Example 1)]
The configuration of the lower router will be described with reference to FIG. Since the lower routers 130A to 130D accommodated in the active star network 100 have the same configuration, the lower router 130A will be described below as an example. FIG. 2 is a diagram illustrating the configuration of the lower router 130A according to the first embodiment. FIG. 2 illustrates a portion closely related to the technology disclosed in the present application. However, it is assumed that the upper router and the lower router according to the first embodiment have a function of a general router as a network device. To do.

  For example, the upper router and the lower router according to the first embodiment have various LAN (Local Area Network) media, various HDLC (High Level Data Link Control), and various WAN (Wide Area Network) functions as general routers. ) It shall have a function to handle media and various network interfaces. Further, the upper router and the lower router according to the first embodiment perform packet distribution between networks based on information in the third layer “network layer” of the OSI (Open Systems Interconnection) reference model as a general router function. It shall have a function.

  As shown in FIG. 2, the lower router 130A includes a failure detection packet transmission reference table 131A, a packet transmission / reception unit 132A, an interface stop unit 133A, and a switching unit 134A.

  The failure detection packet transmission reference table 131A stores information for transmitting a “monitoring icmp (Internet Control Message Protocol) packet” for detecting a communication failure to a specific router set in advance. Here, the communication failure means, for example, a state in which communication regarding the “monitoring icmp packet” in which a response to the “monitoring icmp packet” and the “monitoring icmp packet” is returned cannot be normally performed. When the cable, the network interface, and the device are not operating normally, communication related to the “monitor icmp packet” cannot be performed normally.

  FIG. 3 is a diagram illustrating an example of information stored in the failure detection packet transmission reference table 131A according to the first embodiment. As illustrated in FIG. 3, the failure detection packet transmission reference table 131 </ b> A includes a transmission destination address “subordinate router 130 </ b> B (10.10.1.0)” set in advance as a transmission destination of the “monitoring icmp packet” The port number “1” of the port to be associated is stored in association with each other.

  The packet transmitting / receiving unit 132A transmits a “monitor icmp packet” to a specific router set in advance at a predetermined timing set in advance. For example, the packet transmitting / receiving unit 132A waits for the arrival of the “monitoring icmp packet” transmission timing. When the transmission timing of the “monitor icmp packet” is reached, the packet transmitting / receiving unit 132A acquires the transmission destination address and the port number from the failure detection packet transmission reference table 131A. Next, the packet transmitting / receiving unit 132A sets the transmission destination address acquired from the failure detection packet transmission reference table 131A as the transmission destination address of the “monitoring icmp packet”. Then, the packet transmitting / receiving unit 132A transmits the “monitoring icmp packet” from the port of the port number acquired from the failure detection packet transmission reference table 131A.

  The “monitoring icmp packet” transmitted from the packet transmitting / receiving unit 132A reaches the lower router 130B through the route of the intermediate switch 120A → the upper router 110 → the intermediate switch 120B.

  The interface stop unit 133A stops the network interface when a failure occurs in the communication to be monitored. The interface stopping unit 133A monitors a route on which the “monitoring icmp packet” is delivered, that is, communication on the route of the intermediate switch 120A → the upper router 110 → the intermediate switch 120B. The communication to be monitored includes the lower router 130A, the cable connecting the lower router 130A and the intermediate switch 120A, the intermediate switch 120A, the cable connecting the intermediate switch 120A and the upper router 110, the upper router 110, the upper router 110 and the intermediate switch. Corresponding to communication regarding response to “monitoring icmp packet” and “monitoring icmp packet” performed via cable connecting intermediate switch 120B, intermediate switch 120B, intermediate switch 120B and lower router 130B, and lower router 130B To do.

  Then, the interface stopping unit 133A detects a communication failure to be monitored based on whether a response to the “monitoring icmp packet” is received. For example, the interface stopping unit 133A determines whether a response to the “monitoring icmp packet” is received by the packet transmitting / receiving unit 132A. If the response to the “monitoring icmp packet” is not received by the packet transmitting / receiving unit 132A as a result of the determination, the interface stopping unit 133A determines that a failure has occurred in the communication to be monitored. Then, the interface stopping unit 133A stops the operating network interface.

  When stopping the network interface, the interface stopping unit 133A cannot receive the response to the “monitoring icmp packet” and the response to the “monitoring icmp packet” among the network interfaces of the lower router 130A. Both of the network interfaces closer to the terminal 150A paired with the network interface (network interface for performing communication with the terminal 150A) are stopped. Note that the interface stopping unit 133A may stop all the network interfaces included in the lower router 130A when stopping the network interface.

  For example, among the network interfaces of the lower router 130A, the network interface that has not received a response to the “monitoring icmp packet” and the terminal 150A that is paired with the network interface that has not received the response to the “monitoring icmp packet” For example, a network interface for performing communication with a terminal has a plurality of terminals. For example, the network interface for performing communication with the terminal may be a plurality of terminals. Can be prevented from adversely affecting the communication due to the stop of the interface to other terminals unrelated to the communication failure detection. Further, if the method of stopping all the network interfaces included in the lower router 130A is taken, it is possible to realize the stop of the network interface according to the detection of the communication failure by a simple process.

  On the other hand, when the response to the “monitoring icmp packet” is received by the packet transmitting / receiving unit 132A as a result of the determination, the interface stopping unit 133A determines that no failure has occurred in the communication to be monitored. Then, when a new “monitoring icmp packet” is transmitted from the packet transmitting / receiving unit 132A, the interface stopping unit 133A again determines whether a response to the “monitoring icmp packet” is received by the packet transmitting / receiving unit 132A. .

  Note that the lower router 230A accommodated in the standby-type star network 200 detects that the network interface of the lower router 130A is stopped by using the HSRP function, and performs the actual operation related to packet communication. Switch. When the HSRP function is not applied in the system, the control unit that performs router switching is performed by the lower-level router that performs the actual operation related to packet communication or the like in response to the stop of the operating network interface. Switching can also be performed.

  Here, referring back to FIG. 1, responses to the “monitoring icmp packet” and “monitoring icmp packet” transmitted from each of the lower routers 130A to 130D having the above-described functions are received in the active star network 100. Explain how it circulates. If there is no communication failure in the active star network 100, the “monitoring icmp packet” and the response transmitted from each of the lower routers 130A to 130D circulate as described below.

  As shown by the dotted line in FIG. 1, the “monitoring icmp packet” transmitted from the lower router 130A reaches the lower router 130B through the route of the intermediate switch 120A → the upper router 110 → the intermediate switch 120B. A response to the “monitor icmp packet” transmitted from the lower router 130B reaches the lower router 130A through the reverse route, that is, the route of the intermediate switch 120B → the upper router 110 → the intermediate switch 120A.

  As shown by the dotted line in FIG. 1, the “monitor icmp packet” transmitted from the lower router 130B reaches the lower router 130C through the route of the intermediate switch 120B → the upper router 110 → the intermediate switch 120C. A response to the “monitor icmp packet” transmitted from the lower router 130C reaches the lower router 130B through the reverse route, that is, the route of the intermediate switch 120C → the upper router 110 → the intermediate switch 120B.

  Further, as shown by the dotted line in FIG. 1, the “monitoring icmp packet” transmitted from the lower router 130C reaches the lower router 130D through the route of the intermediate switch 120C → the upper router 110 → the intermediate switch 120D. A response to the “monitor icmp packet” transmitted from the lower router 130D reaches the lower router 130C through the reverse route, that is, the route of the intermediate switch 120D → the upper router 110 → the intermediate switch 120C.

  Further, as indicated by the dotted line in FIG. 1, the “monitoring icmp packet” transmitted from the lower router 130D reaches the lower router 130A through the route of the intermediate switch 120D → the upper router 110 → the intermediate switch 120A. A response to the “monitor icmp packet” transmitted from the lower router 130A reaches the lower router 130D through the reverse route, that is, the route of the intermediate switch 120A → the upper router 110 → the intermediate switch 120D.

  As described above, the combination of the lower-level routers that are the transmission source and the transmission destination of the “monitoring icmp packet” is selected in advance so as not to overlap in the router accommodated in the active star network 100. Then, the “monitoring icmp packet” and the response transmitted from each of the lower routers 130A to 130D are circulated in the active star network 100. In this way, a communication failure occurring in the active star network 100 is detected by circulating the “monitoring icmp packet” in the active star network 100.

  Here, the outline until the switching from the active star network 100 to the standby star network 200 is completed will be described with reference to FIG. FIG. 4 is a diagram for explaining an overview of switching of the network system according to the first embodiment.

  As shown in (1) of FIG. 4, when a communication failure occurs on the cable connecting the upper router 110 and the intermediate switch 120B, the “monitoring icmp packet” transmitted from the lower router 130A is the lower router. 130B is not reached. For this reason, since the lower router 130A does not receive a response to the “monitoring icmp packet” from the lower router 130B, it is determined that a failure has occurred, and the interface is set as shown in (2) of FIG. Stop. Then, the lower router 130A switches the execution subject of the actual operation related to packet communication or the like to the lower router 230A accommodated in the standby star network 200.

  As shown in (3) of FIG. 4, when the interface of the lower router 130A is stopped, the “monitor icmp packet” transmitted from the lower router 130D does not reach the lower router 130A. Therefore, since the lower router 130D does not receive a response to the “monitoring icmp packet” from the lower router 130A, the lower router 130D determines that a failure has occurred, and stops the interface as shown in (4) of FIG. To do. Then, the lower router 130D switches the execution subject of the actual operation related to packet communication or the like to the lower router 230D accommodated in the standby star network 200.

  Similarly, when the interface of the lower router 130D is stopped, the “monitoring icmp packet” transmitted from the lower router 130C does not reach the lower router 130D. Therefore, since the lower router 130C does not receive a response to the “monitoring icmp packet” from the lower router 130D, it determines that a failure has occurred and stops the interface. Then, the lower router 130C switches the execution subject of the actual operation related to packet communication or the like to the lower router 230C accommodated in the standby star network 200.

  Similarly, when the interface of the lower router 130C is stopped, the “monitoring icmp packet” transmitted from the lower router 130B does not reach the lower router 130C. Therefore, since the lower router 130B does not receive a response to the “monitor icmp packet” from the lower router 130C, it determines that a failure has occurred and stops the interface. Then, the lower router 130B switches the execution subject of the actual operation relating to packet communication or the like to the lower router 230B accommodated in the standby star network 200.

  As described with reference to FIG. 4, if any interface of the lower routers 130 </ b> A to 130 </ b> D accommodated in the active star network 100 is stopped, the interface stop and the router switching are propagated. Finally, the switching of the execution subject of the actual operation related to packet communication or the like is completed in the lower routers 230A to 230D accommodated in the Starby-type star network 200. Note that the present invention is not limited to the case where each of the lower routers 130A to 130D accommodated in the active star network 100 autonomously performs switching. For example, a processing function unit that manages router switching is provided in the active star network 100. Then, when all the interfaces of the lower routers 130A to 130D are stopped, the processing function unit may collectively switch the execution subject of the actual operation related to packet communication or the like to the lower routers 230A to 230D. .

[Processing by Subordinate Router (Example 1)]
Next, the flow of processing by the lower router according to the first embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a flow of processing by the lower router according to the first embodiment. Since the lower routers 130A to 130D accommodated in the active star network 100 perform the same processing, the flow of processing of the lower router 130A will be described below as an example of processing by the lower router.

  As illustrated in FIG. 5, the packet transmitting / receiving unit 132A determines whether or not the “monitoring icmp packet” transmission timing has been reached (step S110). As a result of the determination, if the “monitoring icmp packet” transmission timing has not been reached, the determination result is “No” and the determination in step S110 is repeated.

  On the other hand, if the transmission timing of the “monitor icmp packet” has been reached as a result of the determination (step S110, Yes), the packet transmitting / receiving unit 132A transmits the transmission destination address and port number from the failure detection packet transmission reference table 131A. Is acquired (step S120). Next, the packet transmitting / receiving unit 132A sets the destination address acquired from the failure detection packet transmission reference table 131A as the transmission destination address of the “monitoring icmp packet”, and also acquires it from the failure detection packet transmission reference table 131A. “Monitoring icmp packet” is transmitted from the port of the port number (step S130).

  The interface stopping unit 133A determines whether or not a response to the “monitoring icmp packet” has been received by the packet transmitting / receiving unit 132A (step S140). As a result of the determination, when the response to the “monitoring icmp packet” is received by the packet transmitting / receiving unit 132A (Yes in step S140), the interface stopping unit 133A determines that a communication failure has not occurred. Then, the processing by the lower router 130A returns to step S110 described above.

  On the other hand, as a result of the determination, if the response to the “monitoring icmp packet” is not received by the packet transmitting / receiving unit 132A (step S140, No), the interface stopping unit 133A determines that a communication failure has occurred. Then, the interface stopping unit 133A stops the operating network interface (step S150).

[Effects of Example 1]
As described above, according to the first embodiment, for each of the lower routers 130A to 130D accommodated in the active star network 100, a specific router as a transmission destination of the “monitoring icmp packet” is previously set. Select. The lower routers 130 </ b> A to 130 </ b> D transmit “monitoring icmp packets” to specific routers selected in advance. For this reason, the number of packets for detecting a failure in the network can be reduced.

  Furthermore, when the response to the “monitoring icmp packet” is not received, the lower routers 130A to 130D determine that a failure has occurred and stop the network interface. For this reason, it is possible to avoid the occurrence of a situation where there are a plurality of active routers in a redundant star network, and to maintain communication quality.

  Further, according to the first embodiment, the “monitoring icmp packet” is transmitted in a “monitoring icmp packet” so that a combination of lower-level routers serving as a transmission destination and a transmission destination is not duplicated in a router accommodated in the active star network 100. A specific router as a transmission destination of “packet” is selected in advance. For this reason, the “monitoring icmp packet” and the response transmitted from each of the lower routers 130 </ b> A to 130 </ b> D are circulated in the active star network 100, and failure detection failure can be prevented.

  Hereinafter, other embodiments of a communication device, a failure detection method, a failure detection program, a communication system, and a communication method according to the present invention will be described.

(1) Device Configuration, etc. Each component of the lower router 130A shown in FIG. 2 is functionally conceptual, and does not necessarily need to be physically configured as illustrated. The specific form of element distribution / integration is not limited to that shown in the figure. For example, the interface stopping unit 133A and the switching unit 134A included in the lower router 130A illustrated in FIG. 2 are configured to be functionally or physically integrated. As described above, all or a part of the lower router 130A can be configured to be functionally or physically distributed / integrated in arbitrary units according to various loads, usage conditions, and the like.

(2) Failure detection program The various processing functions (see FIG. 5 and the like) of the lower routers accommodated in the active star network 100 described in the first embodiment described above are based on programs prepared in advance. It can also be realized by being executed by a computer system such as a computer or a workstation.

  Therefore, in the following, an example of a computer that executes a failure detection program that realizes a processing function similar to the processing function of the lower router 130A described in the first embodiment will be described with reference to FIG. FIG. 6 is a diagram illustrating a computer that executes a failure detection program.

  As shown in the figure, the computer 400 as a lower router 130A has a CPU (Central Processing Unit) 410 that executes various arithmetic processes. The computer 400 also includes an input device 420 and an output device 430 that receive data input from the user.

  Note that the input device 420 corresponds to, for example, a keyboard or a mouse. The output device 430 corresponds to a monitor, a display, or the like. When the input device 420 includes a mouse, the pointing device function can be realized in cooperation with the monitor included in the output device 430. Also, when the input device 420 has another input device such as a touch pad, the pointing device function can be realized as in the case of the mouse. The device administrator can also make various settings related to the lower router 130A using the pointing device function.

  As shown in FIG. 6, the computer 400 includes a medium reading device 440 that reads a program and the like from a storage medium, and a network interface device 450 that exchanges data with another computer via a network. As shown in FIG. 6, the computer 400 includes a RAM (Random Access Memory) 460 that temporarily stores various types of information and a hard disk device 470. Each device 410 to 470 is connected to a bus 480.

  Instead of the CPU 410 described above, for example, an electronic circuit such as an MPU (Micro Processing Unit) or an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array) can be used. Further, instead of the RAM 460, a semiconductor memory device such as a flash memory can be used.

  The hard disk device 470 stores a failure detection program 471 and failure detection data 472 that perform the same functions as the processing executed by the lower router 130A described above. The failure detection program 471 may be appropriately distributed and stored in a storage unit of another computer that is communicably connected via a network.

  Then, the CPU 410 reads out the failure detection program 471 from the hard disk device 470 and develops it in the RAM 460, whereby the failure detection program 471 functions as a failure detection process 461 as shown in FIG. The failure detection process 461 expands various data such as the failure detection data 472 read from the hard disk device 470 in an area allocated to itself on the RAM 460 as appropriate, and executes various processes based on the expanded data.

  The failure detection process 461 corresponds to, for example, processing executed by the packet transmission / reception unit 132A, the interface stop unit 133A, and the switching unit 134A of the lower router 130A illustrated in FIG.

  Note that the failure detection program 471 is not necessarily stored in the hard disk device 470 from the beginning. For example, each program is stored in a “portable physical medium” such as a flexible disk (FD), a CD-ROM, a DVD disk, a magneto-optical disk, and an IC card inserted into the computer 400. Then, the computer 400 may read and execute each program from these.

  Further, each program is stored in “another computer (or server)” connected to the computer 400 via a public line, the Internet, a LAN, a WAN, or the like. Then, the computer 400 may read and execute each program from these.

(3) Failure Detection Method The following conversion method is realized, for example, by the lower router accommodated in the active star network 100 described in the first embodiment.

  That is, the communication device accommodated in the active network is a failure for detecting a failure in the network with respect to a specific communication device selected in advance from other communication devices accommodated on the active network side. A packet transmission step for transmitting a detection packet (see, for example, step S130 in FIG. 5). When a response corresponding to the failure detection packet transmitted in the packet transmission step is not received from a specific communication device, the network interface is stopped. A failure detection method including an interface stopping step (see, for example, steps S140 and S150 in FIG. 5) is realized. The active network corresponds to the Active star network 100 described in the first embodiment. The failure detection packet corresponds to the “monitoring icmp packet” described in the first embodiment.

  As described above, the communication device, the failure detection method, the failure detection program, the communication system, and the communication method according to the present invention are useful for failure detection in a redundant network, and in particular, the number of packets for detecting a failure in the network. It is suitable for reducing communication and maintaining communication quality.

10 (Active) Star network 11 Upper router 12A-12D Intermediate switch 13A-13D Lower router 14A-14D Switch 15A-15D Terminal 20 (Standby system) Star network 21 Upper router 22A-22D Intermediate switch 23A-23D Lower router 30-32 HSRP
40 (Active) network 41 Upper router 42 HUB
43 Lower router 50 (Standby system) network 51 Upper router 53 Lower router 60 Switch 70 Terminal 80 HSRP
100 (Active system) star network 110 upper router 120A to 120D intermediate switch 130A to 130D lower router 131A failure detection packet transmission reference table 132A packet transmission / reception unit 133A interface stop unit 134A switching unit 140A to 140D switch 150A to 150D terminal 200 ( Standby type) Star network 210 Upper router 220A-220D Intermediate switch 230A-230D Lower router 300 Cable 400 Computer 410 CPU
420 Input Device 430 Output Device 440 Medium Reading Device 450 Network Interface Device 460 RAM
461 Failure detection process 470 Hard disk device 471 Failure detection program 472 Failure detection data 480 Bus

Claims (5)

Each communication device accommodated on the active network side constituting the redundant network
Among other communication devices accommodated on the active network side, the combination of communication devices that are the transmission source and destination of the failure detection packet is not duplicated in the communication devices accommodated on the active network side. advance against selected the particular communication device transmits a fault detection packet for detecting a failure in the network, transmission packets receives a response corresponding to the fault detection packet reception unit in,
If the response corresponding to the transmitted failure detection packets by the packet transmission reception unit is not received from said specific communication device, an interface stop for stopping the network interface,
A switching unit that switches an actual operating subject to a communication device that is accommodated in a standby network and becomes a pair of communication devices in which the network interface is stopped when the network interface is stopped by the interface stop unit; ,
The packet transmitter / receiver
When the network interface is stopped by the interface stop unit, the network interface in the communication device is stopped to the other communication device by not transmitting a response to the failure detection packet received from the other communication device. A communication device characterized by propagating . A failure detection method applied to a communication device accommodated on the active network side of a network system constituting a redundant network,
Among other communication devices accommodated on the active network side, the combination of communication devices that are the transmission source and destination of the failure detection packet is not duplicated in the communication devices accommodated on the active network side. a packet transmission step of transmitting relative preselected specific communication device, the fault detection packet for detecting a failure in the network,
An interface stop step of stopping the network interface when a response corresponding to the failure detection packet transmitted by the packet transmission step is not received from the specific communication device ;
When the network interface is stopped by the network interface stop step, a switching step of switching the operating subject of the actual operation to a communication device that is accommodated in a standby network and becomes a pair of communication devices whose network interface is stopped. Including
The network interface in the communication device is not transmitted to the other communication device by not transmitting a response to the failure detection packet received from the other communication device when the network interface is stopped by the network interface stop step. A failure detection method characterized by propagating a stoppage of a fault. A failure detection program to be executed by a computer as a communication device accommodated on the active network side of a network system constituting a redundant network,
In the computer,
Among other communication devices accommodated on the active network side, the combination of communication devices that are the transmission source and destination of the failure detection packet is not duplicated in the communication devices accommodated on the active network side. a packet transmission step of transmitting relative preselected specific communication device, the fault detection packet for detecting a failure in the network,
An interface stop procedure for stopping a network interface when a response corresponding to the failure detection packet transmitted by the packet transmission procedure is not received from the specific communication device ;
When the network interface is stopped by the interface stop procedure, a switching procedure for switching an actual operating subject to a communication device that is accommodated in a standby network and becomes a pair of communication devices whose network interface is stopped is executed. Let
When the network interface is stopped by the interface stop procedure, the network interface in the communication device is stopped to the other communication device by not transmitting a response to the failure detection packet received from the other communication device. A fault detection program characterized by propagating . A communication system having a redundant network with an active network in which a plurality of communication devices are accommodated and a standby network that backs up the active network when a failure occurs in the active network,
Each communication device accommodated in the operational network is
Among other communication devices accommodated in the operational network, the combination of communication devices that are the transmission source and transmission destination of the failure detection packet is not duplicated in the communication device accommodated on the operational network side. against preselected specific communication device transmits a fault detection packet for detecting a failure in the network, and the packet transmission reception unit for receiving a response corresponding to the fault detection packet,
If the response corresponding to the transmitted failure detection packets by the packet transmission reception unit is not received from said specific communication device, an interface stop for stopping the network interface,
When the network interface is stopped by the interface stop unit, there is a switching unit that switches the operating subject of the actual operation to a communication device that is accommodated in a standby network and becomes a pair of communication devices whose network interface is stopped. And
The packet transmitter / receiver
When the network interface is stopped by the interface stop unit, the network interface in the communication device is stopped to the other communication device by not transmitting a response to the failure detection packet received from the other communication device. A communication system characterized by propagating . The present invention is applied to a communication system having a redundant network of an operational network in which a plurality of communication devices are accommodated and a standby network that backs up the operational network when a failure occurs in the operational network. A communication method,
Each communication device accommodated in the operational network is
Among other communication devices accommodated in the operational network, the combination of communication devices that are the transmission source and transmission destination of the failure detection packet is not duplicated in the communication device accommodated on the operational network side. A failure detection packet for detecting a failure in the network is transmitted to a specific communication device selected in advance.
When a response corresponding to the failure detection packet is not received from the specific communication device, the network interface is stopped ,
When the network interface is stopped, the main operating entity is switched to a communication device that is accommodated in a standby network and is a pair of communication devices in which the network interface is stopped,
Propagating the stop of the network interface in the communication device to the other communication device by not transmitting a response to the failure detection packet received from the other communication device when the network interface is stopped. A characteristic communication method.

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