Abstract:
An information processing system includes a plurality of devices; a relay device configured to relay communication between the terminal device and the plurality of devices; and a management device configured to manage the plurality of devices and the relay device, wherein the relay device is configured to: receive an access request for requesting access to a target device from the terminal device, and broadcast a request packet for acquiring identification information that identifies the target device to the network, the request packet including a network address of the target device, and wherein the management device is configured to: receive the request packet, identify the target device out of the plurality of devices, based on the network address of the target device, acquire configuration information from the identified target device, and update configuration management information including configuration information of each of the plurality of devices using the acquired configuration information.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-124930, filed on Jun. 22, 2015, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to an information processing system, an information processing method, and a storage medium. 
       BACKGROUND 
       [0003]    In an information processing system, a plurality of infrastructure devices, for example, a server, storage, and so on work in concert over a network to attain an operating objective of the system. In the information processing system, a configuration management system for managing a plurality of infrastructure devices is employed. To cause the information processing system to operate as intended, the configuration management system manages configuration information such as information related to physical requirements, design, and operation of the information processing system. If a change has occurred in a configuration or setting (hereinafter collectively referred to as a configuration change) in the information processing system, the configuration management system stores the content of the change in the configuration in the configuration management system. Further, the configuration management system may efficiently control the change in the information processing system by checking whether the content of the change is actually reflected in the information processing system. 
         [0004]    A system is known in which an address monitor agent monitors a domain name service (DNS) and, if a change has occurred in the setting details, issues a notification to an address information monitor manager, and thus, consistency of address information is maintained in the system with the address information monitor manager (for example, see Japanese Laid-open Patent Publication No. 2004-147132). 
         [0005]    A system is known in which, in order to manage devices coupled to a network, IP addresses corresponding to devices in the system are searchable (for example, see Japanese Laid-open Patent Publication No. 2007-221565). 
         [0006]    A method is known in which data packets transmitted over a network are monitored in order to cause a router to reflect the configuration of devices coupled to the network (for example, see Japanese National Publication of International Patent Application No. 2005-513832). 
         [0007]    Among asset management systems that manage assets in systems, a system to reduce the load is known (for example, see Japanese Laid-open Patent Publication No. 2009-301409). This system determines the loads of a server, which includes an asset management manager, and a configuration information management database, and, based on the determination, permits or does not permit transmission of configuration information. 
         [0008]    A configuration management system that regularly collects configuration information from infrastructure devices in an information processing system, for example, through polling, thus manages the latest configuration information of the infrastructure devices. However, if the maintainer changes the configuration of the infrastructure devices, the configuration information managed by the configuration management system will be inconsistent with the actual configuration information of infrastructure devices until regular processing for collecting the content of the change is performed by the configuration management system. 
         [0009]    When the maintainer changes the configuration of infrastructure devices in the environment where the time intervals at which the configuration management system collects the latest configuration information are long, the period of time during which the configuration information managed by the configuration management system is inconsistent with the actual configuration information of infrastructure devices is likely to be long. In contrast, when the time interval at which the configuration management system collects the latest configuration information is reduced, there is a possibility that the loads on the configuration management system and infrastructure devices will be increased. Further, the network is more likely to be congested. Therefore, it is desirable to reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of the infrastructure devices occurs. 
       SUMMARY 
       [0010]    According to an aspect of the invention, an information processing system includes a plurality of devices coupled to one another via a network; a relay device coupled to a terminal device and configured to relay communication between the terminal device and the plurality of devices; and a management device configured to manage the plurality of devices and the relay device, wherein the relay device is configured to: receive an access request for requesting access to a target device from the terminal device, and broadcast a request packet for acquiring identification information that identifies the target device to the network, the request packet including a network address of the target device, and wherein the management device is configured to: receive the request packet, identify the target device out of the plurality of devices, based on the network address included in the request packet, acquire configuration information from the identified target device, and update configuration management information including configuration information of each of the plurality of devices using the acquired configuration information. 
         [0011]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0012]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a diagram illustrating an example of an information processing system according to a first embodiment; 
           [0014]      FIG. 2  is a diagram illustrating an example of a hardware configuration of a configuration management device; 
           [0015]      FIG. 3  is a diagram depicting an example of a device DB; 
           [0016]      FIG. 4  is a diagram depicting an example of a configuration management DB; 
           [0017]      FIG. 5  is a diagram illustrating an example of a format of an ARP request packet; 
           [0018]      FIG. 6  is a sequence diagram illustrating an example of processing of an information processing system according to the first embodiment; 
           [0019]      FIG. 7  is a flowchart illustrating an example of processing of the configuration management device according to the first embodiment; 
           [0020]      FIG. 8A  is a sequence diagram illustrating an example of processing of an information processing system according to a second embodiment; 
           [0021]      FIG. 8B  is a sequence diagram illustrating an example of processing of the information processing system according to the second embodiment; 
           [0022]      FIG. 9  is a diagram illustrating an example of a format of a GARP packet; 
           [0023]      FIG. 10  is a flowchart illustrating an example of processing of the information processing system according to the second embodiment; 
           [0024]      FIG. 11  is a diagram illustrating an example of an information processing system according to a third embodiment; 
           [0025]      FIG. 12  is a sequence diagram illustrating an example of processing of the information processing system according to the third embodiment; 
           [0026]      FIG. 13  is a diagram illustrating an example of information transmitted from the configuration management device to a configuration management server; 
           [0027]      FIG. 14  is a flowchart illustrating an example of processing of a configuration management device according to the third embodiment; 
           [0028]      FIG. 15A  is a sequence diagram illustrating an example of processing of an information processing system according to a fourth embodiment; and 
           [0029]      FIG. 15B  is a sequence diagram illustrating an example of processing of the information processing system according to the fourth embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    Hereinafter, with reference to the accompanying drawings, embodiments will be described in detail. 
         [0031]      FIG. 1  is a diagram illustrating an example of an information processing system according to a first embodiment. An information processing system  100  includes a router  120 , a management local area network (LAN)  130 , a configuration management device  200 , and a device  140   a  to a device  140   n . The router  120  is a relay device that couples the management LAN  130  to a network including a maintenance terminal  110 . The device  140   a  to the device  140   n  are infrastructure devices (hereinafter, the device  140   a  to the device  140   n  are also collectively as devices  140 ). The device  140  is sometimes referred to as a device. The configuration management device  200  is a device that manages configuration information of the router  120  and the device  140   a  to the device  140   n . The management LAN  130  is coupled so that the configuration management device  200  manages the router  120  and the device  140   a  to the device  140   n . The configuration management device  200  includes a receiving unit  201 , a determination unit  202 , an acquisition unit  203 , a processing unit  204 , and a storage unit  205 . Specific processing of components will be described in (1) to (8) below. The storage unit  205  includes a configuration management database (DB)  206  and a device DB  207 . The device DB  207  stores Internet protocol (IP) addresses and media access control (MAC) addresses corresponding to the router  120  and the device  140   a  to the device  140   n  that the configuration management device  200  manages. The configuration management DB  206  stores the IP addresses, the MAC addresses, and the configuration information of the router  120  and the device  140   a  to the device  140   n.    
         [0032]    The information processing system  100  is accessible from the maintenance terminal  110 . The maintenance terminal  110  is a terminal used when the maintainer operates the devices  140 . The maintainer may access the devices  140  through the router  120  and the management LAN  130  by using the maintenance terminal  110 . A business LAN  150  is a LAN for access to the devices  140  and is used for access for a purpose different from management. 
         [0033]    Hereinafter, a process related to the information processing system  100  according to the first embodiment will be sequentially described. 
         [0034]    (1) The maintenance terminal  110  transmits an access request for access to an IP address to be accessed that is input by the maintainer, to the router  120 . 
         [0035]    (2) The router  120  broadcasts an address resolution protocol (ARP) request packet to the device  140   a  to the device  140   n  and the configuration management device  200  on the management LAN  130 . The ARP request packet is transmitted so that the router  120  acquires a MAC address corresponding to the IP address of the device  140  to be accessed. In other words, the ARP packet is a packet for requesting address resolution (an address resolution request packet). 
         [0036]    (3) The ARP request packet transmitted from the router  120  is broadcast on the management LAN  130 . That is, this ARP request packet arrives at not only the device  140   a  to the device  140   n  but also the configuration management device  200 . Consequently, the receiving unit  201  in the configuration management device  200  receives the ARP request packet transmitted from the router  120 . 
         [0037]    (4) The determination unit  202  first determines whether or not the received packet is an ARP request packet. Next, the determination unit  202  determines the IP address contained in the ARP request packet. Specifically, the determination unit  202  determines whether or not the transmission source of the ARP request packet is the router  120 . Further, the determination unit  202  determines whether or not the value of the target IP address (the destination IP address) of the ARP payload in the ARP request packet is the IP address of the device  140  that the configuration management device  200  manages. In other words, it is determined whether or not the transmission source of the ARP request packet is the router  120  and the destination IP address is the IP address of the device  140  being managed by the configuration management device  200 . 
         [0038]    (5) If the transmission source of an ARP request packet is the router  120 , and the destination IP address is the IP address of the device  140  being managed by the configuration management device  200 , the determination unit  202  determines that the configuration change for the device  140  has been made. In this case, the determination unit  202  transmits an instruction to the acquisition unit  203  to acquire the configuration information of the device  140  to be accessed. For example, if the IP address of the device  140   a  is stored in the payload of the received ARP request packet, the determination unit  202  gives an instruction to the acquisition unit  203  instructing the acquisition unit  203  to acquire the configuration information of the device  140   a.    
         [0039]    (6) The acquisition unit  203  acquires the configuration information of the device  140  to be accessed. At this point, for example, the acquisition unit  203  requests the target device to offer the configuration information. Further, in response to the request, the target device transmits the configuration information to the configuration management device  200 . It is preferable that the acquisition unit  203 , after receiving the instruction, estimate the maintenance time actually taken by the maintainer and wait for a given period of time and then acquire the configuration information of the device  140  to be accessed. 
         [0040]    (7) The processing unit  204  causes the configuration management DB  206  in the storage unit  205  to reflect the acquired configuration information. That is, the configuration information of the target device is updated with the newly acquired configuration information. Consequently, disagreement between the configuration information actually set in the target device and the configuration information managed by the configuration management device  200  is resolved. 
         [0041]    (8) The instruction unit  208  transmits an instruction to delete or initialize an entry related to the device  140  to be accessed included in the ARP table  121  in the router  120 , to the router  120 . According to the received instruction, the router  120  deletes or initializes the entry related to the device  140  to be accessed in the ARP table  121 . The ARP table  121  is an association information table storing the IP addresses and the MAC addresses of the devices  140  in association with each other. The router  120  may perform address resolution for access with a specified IP address based on the ARP table  121  by storing the IP addresses and the MAC addresses of the devices  140  in association with each other in the ARP table  121 . However, if the entry related to the device  140  to be accessed is deleted in the processing of (8) and thus access from the maintenance terminal  110  to this device  140  is provided, the router  120  is able to transmit an ARP request packet again. 
         [0042]    As described above, the configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ARP request packet transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140  for which the configuration information has been changed. That is, immediately after the configuration information of the device  140  is changed, the configuration management device  200  may acquire the latest configuration information from that device  140 . Thus, the configuration management device  200  may reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of infrastructure devices occurs. Since, when acquiring configuration information from the target device, the configuration management device  200  does not have to access another device, the load on the network is suppressed compared to a method of collecting configuration information through polling or the like. 
         [0043]      FIG. 2  is a diagram illustrating an example of a hardware configuration of a configuration management device. The configuration management device  200  includes a processor  11 , a memory  12 , a bus  15 , an external storage device  16 , and a network coupling device  19 . Further, the configuration management device  200  may optionally include an input device  13 , an output device  14 , a medium driving device  17 . The configuration management device  200  is sometimes implemented, for example, by a server, a computer, or the like. 
         [0044]    The processor  11  may be an arbitrary processing circuit including a central processing unit (CPU). The processor  11  operates as the processing unit  204  and the determination unit  202 . The processor  11  is capable of, for example, executing a program stored in the external storage device  16 . The memory  12  operates as the storage unit  205 . Further, the memory  12  stores data obtained by operation of the processor  11  and data for use in processing of the processor  11  as appropriate. The network coupling device  19  is used for communication with another device and operates as the receiving unit  201 , the acquisition unit  203 , and the instruction unit  208 . 
         [0045]    The input device  13  is implemented, for example, as a button, a keyboard, a mouse, or the like. The output device  14  is implemented as a display or the like. The bus  15  couples the processor  11 , the memory  12 , the input device  13 , the output device  14 , the external storage device  16 , the medium driving device  17 , and the network coupling device  19  so that they pass data to and from one another. The external storage device  16  stores programs, data, and the like and offers the stored information to the processor  11  and so on as appropriate. The medium driving device  17  is capable of outputting data in the memory  12  and the external storage device  16  to the portable storage medium  18  and reading programs, data, and so on from the portable storage medium  18 . The portable storage medium  18  is any storage medium capable of being carried around, examples of which include a flexible disc, a magnet-optical (MO) disc, a compact disc recordable (CD-R), and a digital versatile disc recordable (DVD-R). 
         [0046]      FIG. 3  is a diagram depicting an example of a device DB. The device DB  207  stores IP addresses and MAC addresses corresponding to the router  120  and the device  140   a  to the device  140   n  that the configuration management device  200  manages. 
         [0047]    The device DB  207  includes categories of names, IP addresses, and MAC addresses. The names are the names of devices that the configuration management device  200  manages. The IP addresses are IP addresses that correspond to devices and are used on the side of the management LAN  130 . The MAC addresses are MAC addresses that correspond to devices and are used on the side of the management LAN  130 . For example, in the example of  FIG. 3 , an IP address “192.168.0.11” and a MAC address “AA:BB:CC:DD:EE:01” corresponding to the device  140   a  are stored in the device DB  207 . An IP address “192.168.0.12” and a MAC address “AA:BB:CC:DD:EE:02” corresponding to the device  140   b  are stored in the device DB  207 . An IP address “192.168.0.13” and a MAC address “AA:BB:CC:DD:EE:03” corresponding to the device  140   c  are stored in the device DB  207 . An IP address is an example of a network address. A MAC address is an example of hardware identification information. 
         [0048]    The determination unit  202  analyzes the IP address of the transmission destination (target IP address) contained in the payload in an ARP request packet and determines whether or not the IP address concerned is an IP address stored in the device DB. In such a way, the determination unit  202  may make a determination as to whether or not the device  140  to be accessed is a device being managed. Further, the determination unit  202  may determine that a configuration change for the device  140  has been made. 
         [0049]      FIG. 4  is a diagram depicting an example of a configuration management DB. The configuration management DB  206  stores IP addresses and MAC addresses corresponding to the router  120  and the device  140   a  to the device  140   n  that the configuration management device  200  manages, and configuration information. 
         [0050]    The configuration management DB  206  includes categories of names, IP addresses, MAC addresses, and configuration information. The names, the IP addresses, and the MAC addresses are categories similar to those in the device DB  207 . The configuration management DB  206  stores information indicating configuration information of each device. The configuration information is acquired from the respectively corresponding devices  140  by the acquisition unit  203 . 
         [0051]      FIG. 5  is a diagram depicting an example of a format of an ARP request packet. The ARP request packet includes information such as a MAC destination address (DA)  301 , a MAC source address (SA)  302 , a type  303 , and an ARP payload  304 . Address information indicating a broadcast address is stored in the MAC DA  301 . The MAC address of the router  120  is stored in the MAC SA  302 . Information indicating that this packet is an ARP request packet is stored in the type  303 . 
         [0052]    The ARP payload  304  includes a hardware type  305 , a protocol type  306 , a hardware length  307 , a protocol length  308 , an operation  309 , a sender hardware (H/W) address  310 , a sender IP address  311 , a target H/W address  312 , and a target IP address  313 . In the hardware type  305 , information indicating the type of a network in use is stored, for example, “1” indicating Ethernet is stored. In the protocol type  306 , information indicating a protocol in use for the network layer is stored, for example, 0x0800 indicating TCP/IP is stored. In the hardware length  307 , information indicating the length of a MAC address, which is a hardware address, is stored. In the protocol length  308 , information indicating the length of an IP address, which is a protocol address, is stored. In the operation  309 , “1”, which is information indicating an ARP request is stored. In the sender H/W address  310 , the MAC address of the router  120 , which is the transmission source of an ARP request packet, is stored. In the sender IP address  311 , the IP address of the router  120 , which is the transmission source of an ARP request packet, is stored. In the target H/W address  312 , the MAC address of the device  140  to be accessed is stored. However, at the time point of an address request packet, the router  120  has not acquired the MAC address, and therefore “null” indicating vacancy is stored. In the target IP address  313 , the IP address of the device  140  to be accessed is stored. 
         [0053]      FIG. 6  is a sequence diagram illustrating an example of processing of an information processing system according to the first embodiment. The sequence diagram in  FIG. 6  illustrates an example of a process performed when access from the maintenance terminal  110  to the device  140   b  is performed. 
         [0054]    The maintainer inputs the IP address of the device  140   b  to be accessed, to the maintenance terminal  110  to attempt accessing the device  140   b  using secure shell (ssh). The maintenance terminal  110  transmits an access request for the device  140   b  to the router  120  (S 101 ). The router  120  broadcasts an ARP request packet for acquiring the MAC address corresponding to the IP address of the device  140   b  included in the access request, to the device  140   a  to the device  140   n  and the configuration management device  200  on the management LAN  130  (S 102 ). That is, the ARP request packet arrives at not only the device  140   a  to the device  140   n  but also the configuration management device  200 . The ARP request packet transmitted in S 102  is a packet in a format depicted in  FIG. 5 . 
         [0055]    Here, the sender IP address  311  is set to the IP address of the router  120 . Since, in this example, access to the device  140   b  is performed, the target IP address  313  is set to the IP address “192.168.0.12” of the device  140   b . At this point, the MAC address corresponding to this IP address is not identified, the target H/W address  312  is “null”. 
         [0056]    Upon receiving the ARP request packet, the device  140   b  transmits an ARP response packet, which is an address resolution packet, to the router  120  (S 103 ). The ARP response packet contains the MAC address of the device  140   b . The router  120 , upon acquiring the MAC address of the device  140   b , transmits an access request to the device  140   b  (S 104 ). The router  120  establishes a session from the maintenance terminal  110  to the device  140   b  (S 105 ). The maintainer changes the configuration of the device  140   b  through the maintenance terminal  110  (S 106 ). 
         [0057]    Having received the ARP request packet through the broadcast to the device  140   a  to the device  140   n  and the configuration management device  200  performed in S 102 , the configuration management device  200  starts execution of the process in and after S 107  in parallel to the process in S 103 . The determination unit  202  of the configuration management device  200  analyzes the IP address of the transmission source (the sender IP address  311 ) of the ARP request packet using the device DB  207  and determines whether or not the transmission source is the router  120  (S 107 ). The determination unit  202  analyzes the IP address of the transmission destination (the target IP address  313 ) included in the payload in the ARP request packet. Further, the determination unit  202  determines whether or not the device  140   b  serving as the destination is a device being managed by the configuration management device  200  (S 108 ). 
         [0058]    In this example, the sender IP address  311  of the ARP request packet is set to the IP address of the router  120 . Therefore, the determination unit  202  determines that the transmission source of the ARP request packet is the router  120 . Further, the target IP address  313  of the ARP request packet is set to “192.168.0.12”. Therefore, with reference to the device DB  207  depicted in  FIG. 3 , the determination unit  202  determines that the destination of the ARP request packet (that is, the device  140   b ) is a device being managed by the configuration management device  200 . 
         [0059]    The acquisition unit  203  transmits an acquisition request for the latest configuration information to the device  140   b  identified in S 108  (S 109 ). The process in S 109  is executed by the acquisition unit  203  after the acquisition unit  203  has been in a standby state for a given period of time after the process in S 108 . It is preferable that the “given period of time” be, for example, longer than the estimated working hours for maintenance performed by the maintainer. In response to the request from the configuration management device  200 , the device  140   b  transmits the latest configuration information to the acquisition unit  203  of the configuration management device  200  (S 110 ). The processing unit  204  causes the configuration management DB  206  in the storage unit  205  to reflect the acquired configuration information (S 111 ). 
         [0060]    The process in S 111  results in that the processing unit  204  stores the acquired configuration information “config#02” of the device  140   b  in association with the device  140   b , as depicted in the configuration management DB  206  in  FIG. 4 . Thereafter, the instruction unit  208  transmits an instruction to delete an entry related to the device  140   b  included in the ARP table  121  in the router  120 , to the router  120  (S 112 ). The router  120  carries out the received instruction to delete the entry in the ARP table  121  related to the device  140   b  (S 113 ). 
         [0061]    The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing the ARP request packet transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140 . Thus, it is possible to reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of the infrastructure devices occurs. 
         [0062]      FIG. 7  is a flowchart illustrating an example of processing of a configuration management device according to the first embodiment. The receiving unit  201  in the configuration management device  200  receives a packet transmitted from the router  120  (S 201 ). The determination unit  202  determines whether or not the received packet is an ARP request packet (S 202 ). If the received packet is not an ARP request packet (No in S 202 ), the configuration management device  200  terminates the process according to the first embodiment. On the other hand, if the received packet is an ARP request packet (Yes in S 202 ), the determination unit  202  determines whether or not the transmission source of the ARP request packet is the router  120  (S 203 ). If the transmission source of the ARP request packet is not the router  120  (No in S 203 ), the configuration management device  200  terminates the process according to the first embodiment. On the other hand, if the transmission source of the ARP request packet is the router  120  (Yes in S 203 ), the determination unit  202  searches the device DB  207  using the destination IP address of the ARP payload (S 204 ). The determination unit  202  determines whether or not there is an entry corresponding to the destination IP address in the device DB  207  (S 205 ). If there is no entry corresponding to the destination IP address in the device DB  207  (No in S 205 ), the configuration management device  200  terminates the process according to the first embodiment. 
         [0063]    On the other hand, if there is an entry corresponding to the destination IP address in the device DB  207  (Yes in S 205 ), the acquisition unit  203  determines whether or not a certain period of time has passed after the process in S 205  (S 206 ). If the certain period of time has not passed after the process in S 205  (No in S 206 ), the acquisition unit  203  repeats the process in S 206 . On the other hand, if the certain period of time has passed after the process in S 205  (Yes in S 206 ), the acquisition unit  203  acquires the configuration information of the device  140  to be accessed (S 207 ). The processing unit  204  causes the configuration management DB  206  in the storage unit  205  to reflect the acquired configuration information (S 208 ). The instruction unit  208  transmits an instruction to delete an entry related to the device  140  to be accessed included in the ARP table  121  in the router  120 , to the router  120  (S 209 ). Upon completion of the process in S 209 , the configuration management device  200  completes the process according to the first embodiment. 
         [0064]    The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ARP request packet transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140 , and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of the infrastructure devices. 
         [0065]      FIG. 8A  and  FIG. 8B  are sequence diagrams illustrating an example of processing of an information processing system according to a second embodiment. The information processing system according to the second embodiment has a configuration similar to that in  FIG. 1  illustrating an example of the information processing system according to the first embodiment. Therefore, the same components as in  FIG. 1  are denoted by the same reference numerals. 
         [0066]    The processing of the information processing system according to the second embodiment and the processing of the information processing system according the first embodiment are the same in the process in S 101  to S 111  in  FIG. 6 . In the processing of the information processing system according to the second embodiment, the configuration management device  200  uses a gratuitous ARP (GARP) as an alternative to the processing of deleting the ARP table  121  of the router  120 . An example of the process of the information processing system according to the second embodiment using a GARP packet will be described below. The process in S 101  to S 111  is similar to that in  FIG. 6  and therefore the description thereof is omitted. 
         [0067]    Upon completion of the process in S 111 , the instruction unit  208  of the configuration management device  200  transmits a GARP packet  1  (described in detail with reference to  FIG. 9 ) in order to update the ARP table  121  of the router  120  (S 301 ). The router  120  updates the ARP table  121  based on the received GARP packet  1  (S 302 ). Here, the GARP packet  1  contains the IP address of the device  140   b  for which a change in setting has been made by the maintainer, and the MAC address of the configuration management device  200 . Thus, the IP address of the device  140   b  and the MAC address of the configuration management device  200  are set in association with each other in the ARP table  121  of the router  120 . Thereby, if, next, the maintainer attempts accessing the device  140   b  using ssh, an ssh message requesting ssh access is transferred to the configuration management device  200 . 
         [0068]    If there is access to the device  140   b  using ssh (the second time), the maintenance terminal  110  transmits an access request for the device  140   b  to the router  120  (S 303 ). The router  120  transmits an ssh message requesting access, to the configuration management device  200  (S 304 ). Upon detecting the request for access, the instruction unit  208  of the configuration management device  200  transmits a GARP packet  2  (described in detail with reference to  FIG. 9 ) to the router  120  (S 305 ). The router  120  updates the ARP table  121  based on the received GARP packet  2  (S 306 ). The GARP packet  2  contains the IP address of the device  140   b  for which a change in setting has been made by the maintainer, and the MAC address of the device  140   b . Thus, the IP address of the device  140   b  and the MAC address of the device  140   b  are stored in association with each other in the ARP table  121  of the router  120 . Since the access request in S 303  does not result in access to the device  140   b , the maintenance terminal  110  fails in processing and times out. 
         [0069]    The maintenance terminal  110  transmits an access request for the device  140   b  to the router  120  by retry processing (S 307 ). The router  120 , upon acquiring the MAC address of the device  140   b , establishes a session from the maintenance terminal  110  to the device  140   b  (S 308 ). The maintainer changes the configuration of the device  140   b  through the maintenance terminal  110  (S 309 ). 
         [0070]    The configuration management device  200 , upon receiving the ssh message in S 304 , starts execution of the process in and after S 310  in parallel to the process in S 306  and so on. The determination unit  202  of the configuration management device  200  analyzes the received ssh message and determines whether or not the transmission source is the router  120  (S 310 ). The ssh message contains the IP addresses of the transmission source router  120  and the device  140  to be accessed. The determination unit  202  analyzes the IP address of the transmission destination in the ssh message. Then, the determination unit  202  determines whether or not the device  140   b  serving as the destination is a device being managed by the configuration management device  200  (S 311 ). The acquisition unit  203  transmits a request for acquiring the latest configuration information to the device  140   b  (S 312 ). The process in S 312  is executed by the acquisition unit  203  after the acquisition unit  203  has been in a standby state for a given period of time after the process in S 311 . The device  140   b  transmits the latest configuration information to the acquisition unit  203  of the configuration management device  200  (S 313 ). The processing unit  204  causes the configuration management DB  206  in the storage unit  205  to reflect the acquired configuration information (S 314 ). 
         [0071]    Through the process in S 301  to S 314 , the process as in the first embodiment may be executed without deleting or initializing the ARP table  121 . The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ssh message transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140  and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of infrastructure devices occurs. 
         [0072]      FIG. 9  is a diagram illustrating an example of a format of a GARP packet. The GARP packet has a format similar to the format of the ARP request packet in  FIG. 5 . The GARP packet  1  and the GARP packet  2  both contain information such as a MAC DA  401 , a MAC SA  402 , a type  403 , and an ARP payload  404 . The MAC address of the router  120  is stored in the MAC DA  401 . The MAC address of the configuration management device  200  is stored in the MAC SA  402 . Information indicating that this packet is an ARP request packet may be stored in the type  403 . 
         [0073]    The ARP payload  404  includes a hardware type  405 , a protocol type  406 , a hardware length  407 , a protocol length  408 , an operation  409 , a sender H/W address  410 , a sender IP address  411 , a target H/W address  412 , and a target IP address  413 . The hardware type  405 , the protocol type  406 , the hardware length  407 , and the protocol length  408  are similar as in  FIG. 5  and therefore the description of these components is omitted. 
         [0074]    The operations  409  of the GARP packet  1  and the GARP packet  2  both store “2”, which is information indicating an ARP response in response to an ARP request. The MAC address of the configuration management device  200  is stored in the sender H/W address  410  and the target H/W address  412  of the GARP packet  1 . The IP address of the device  140  to be accessed is stored in the sender IP address  411  and the target IP address  413  of the GARP packet  1 . 
         [0075]    The MAC address of the device  140  to be accessed, which is stored in the device DB  207 , is stored in the sender H/W address  410  and the target H/W address  412  of the GARP packet  2 . The IP address of the device  140  to be accessed, which is stored in the device DB  207 , is stored in the sender IP address  411  and the target IP address  413  of the GARP packet  2 . 
         [0076]    The router  120  implements the information processing system according to the second embodiment by updating the ARP table  121  based on the GARP packet  1  and the GARP packet  2 . 
         [0077]      FIG. 10  is a flowchart illustrating an example of processing of the information processing system according to the second embodiment. The receiving unit  201  in the configuration management device  200  receives a packet transmitted from the router  120  (S 401 ). The determination unit  202  determines whether or not the received packet is an ARP request packet (S 402 ). If the received packet is an ARP request packet (Yes in S 402 ), then the determination unit  202  determines whether or not the transmission source of the ARP request packet is the router  120  (S 403 ). If the transmission source of the ARP request packet is not the router  120  (No in S 403 ), the configuration management device  200  terminates the process according to the second embodiment. On the other hand, if the transmission source of the ARP request packet is the router  120  (Yes in S 403 ), the determination unit  202  searches the device DB  207  using the destination IP address of the ARP payload (S 404 ). The determination unit  202  determines whether or not there is an entry corresponding to the destination IP address in the device DB  207  (S 405 ). If there is no entry corresponding to the destination IP address in the device DB  207  (No in S 405 ), the configuration management device  200  terminates the process according to the second embodiment. 
         [0078]    On the other hand, there is an entry corresponding to the destination IP address in the device DB  207  (Yes in S 405 ), the acquisition unit  203  determines whether or not a certain period of time has passed after the process in S 405  (S 406 ). If the certain period of time has not passed after the process in S 405  (No in S 406 ), the acquisition unit  203  repeats the process in S 406 . On the other hand, if the certain period of time has passed after the process in S 405  (Yes in S 406 ), the acquisition unit  203  acquires the configuration information of the device  140  to be accessed (S 407 ). The processing unit  204  causes the configuration management DB  206  in the storage unit  205  to reflect the acquired configuration information (S 408 ). The processing unit  204  temporarily stores the IP address and the MAC address of the device  140 . Further, the instruction unit  208  transmits the GARP packet  1  including the IP address and the MAC address of the configuration management device  200  to the router  120  (S 409 ). Upon completion of the process in S 409 , the configuration management device  200  completes the process according to the second embodiment. 
         [0079]    If the received packet is not an ARP request packet (No in S 402 ), the determination unit  202  determines whether or not coupling using ssh is provided (S 410 ). If ssh coupling is provided (Yes in S 410 ), the instruction unit  208  transmits the GARP packet  2  including the IP address and the MAC address of the device for which a change in setting has been made, to the router  120  (S 411 ). Upon completion of the process in S 411 , the configuration management device  200  executes the process from S 404 . When the process in S 404  is executed subsequently to the process in S 411 , the process is executed using the IP address in an ssh message. 
         [0080]    Through the process in S 401  to S 411 , the process as in the first embodiment may be executed without deleting or initializing the ARP table  121 . The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ssh message transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140  and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of infrastructure devices occurs. 
         [0081]      FIG. 11  is a diagram illustrating an example of an information processing system according to a third embodiment. In  FIG. 11 , components in a configuration similar to that in  FIG. 1  are denoted by the same reference numerals. The configuration management device  200  in the third information processing system  100  neither include the acquisition unit  203  nor the configuration management DB  206 . In the information processing system  100  according to the third embodiment, an acquisition unit  211  and a configuration management DB  212 , which are alternatives to the acquisition unit  203  and the configuration management DB  206 , are provided as a configuration management server  210  outside the configuration management device  200 . 
         [0082]    If the transmission source of an ARP request packet is the router  120  and the destination IP address is the IP address of the device  140  being managed by the configuration management device  200 , the determination unit  202  determines that a configuration change for the device  140  has been made. The instruction unit  208  transmits a request for acquiring the configuration information of the device  140  of the destination IP address contained in the ARP request packet to the acquisition unit  211  of the configuration management server  210 . The acquisition unit  211  acquires the latest configuration information from the device  140  to be accessed, according to the request for acquiring the configuration information. The acquisition unit  211  acquires the latest configuration information from the device  140  and causes the configuration management DB  212  to reflect the configuration information. 
         [0083]    The configuration management server  210  is, for example, a server capable of regularly acquiring the latest configuration information of the device  140 . Coupling the configuration management device  200  to the configuration management server  210  makes it possible to readily implement the information processing system according to the third embodiment. The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ARP request packet transmitted from the router  120 . Thereafter, the configuration management server  210  acquires the latest configuration information from the device  140  and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management server  210  and the actual configuration information of infrastructure devices occurs. Since, when acquiring configuration information from the target device, the configuration management server  210  does not have to access another device, the load on the network is suppressed compared to a method of collecting configuration information through polling or the like. 
         [0084]      FIG. 12  is a sequence diagram illustrating an example of processing of the information processing system according to the third embodiment. The process in S 101  to S 106  in  FIG. 12  is the same as the process in S 101  to S 106  in  FIG. 6 . 
         [0085]    Having received an ARP request packet through the broadcast to the device  140   a  to the device  140   n  and the configuration management device  200  performed in S 102 , the configuration management device  200  starts execution of the process in and after S 501  in parallel to the process in S 103 . The determination unit  202  of the configuration management device  200  analyzes the IP address (the sender IP address  311 ) of the transmission source of the ARP request packet and determines whether or not the transmission source is the router  120  (S 501 ). The determination unit  202  analyzes the IP address of the transmission destination (the target IP address  313 ) included in the payload in the ARP request packet. The determination unit  202  then determines whether or not the destination device  140   b  is a device being managed by the configuration management device  200  (S 502 ). The device  140  being managed is stored in the device DB  207 . 
         [0086]    The instruction unit  208  notifies the acquisition unit  211  of the configuration management server  210  of the IP address of the  140   b  accessed (S 503 ). The process in S 503  is executed by the instruction unit  208  after the instruction unit  208  has been in a standby state for a given period of time after the process in S 502 . The instruction unit  208  transmits, to the router  120 , an instruction to delete an entry related to the device  140   b  included in the ARP table  121  in the router  120  (S 504 ). The router  120  executes the received instruction to delete the entry in the ARP table  121  related to the device  140   b  (S 505 ). 
         [0087]    The acquisition unit  211  of the configuration management server  210  transmits a request for the latest configuration information to the device  140   b  (S 506 ). The device  140   b  transmits the latest configuration information to the acquisition unit  211  of the configuration management server  210  (S 507 ). The acquisition unit  211  causes the configuration management DB  212  to reflect the acquired configuration information (S 508 ). The process in S 504  to S 505  and the process in S 506  to S 508  may be executed in parallel. 
         [0088]      FIG. 13  is a diagram depicting an example of information transmitted from the configuration management device to the configuration management server. The instruction unit  208  of the configuration management device  200  transmits an IP address notification message including the IP address of the device  140  to be accessed, to the acquisition unit  211  of the configuration management server  210 . 
         [0089]    The IP address notification message contains an Ethernet header  501 , an IP header  502 , a TCP header  503 , an HTTP header  504 , and an HTTP payload  505 . Information indicating that Ethernet is used for transmission of an IP address notification message is stored in the Ethernet header  501 . The IP address of the configuration management device  200  serving as the transmission source is stored in the IP header  502 . Information indicating that the TCP protocol is used for transmission of an IP address notification message is stored in the TCP header  503 . Information indicating the URL of the acquisition unit  211  of the configuration management server  210  is stored in the HTTP header  504 . The IP address of the device  140  to be accessed is included in the HTTP payload  505 . 
         [0090]    The instruction unit  208  specifies an URL indicating the acquisition unit  211  contained in the HTTP header  504  to notify the acquisition unit  211  of the configuration management server  210  of the IP address of the device  140   b  to be accessed contained in the HTTP payload. 
         [0091]      FIG. 14  is a flowchart illustrating an example of processing of the configuration management device according to the third embodiment. The process in S 601  to S 606 , which is the process executed by the configuration management device  200  according to the third embodiment, are the same as the process in S 201  to S 206 , which is the process executed by the configuration management device  200  according to the first embodiment in  FIG. 7 . 
         [0092]    Upon completion of the process in S 606 , the instruction unit  208  of the configuration management device  200  transmits an IP address notification message to the acquisition unit  211  of the configuration management server  210  (S 607 ). The instruction unit  208  transmits, to the router  120 , an instruction to delete an entry related to the device  140  to be accessed, the entry being included in the ARP table  121  in the router  120  (S 608 ). 
         [0093]    The configuration management device  200  may detect that the configuration of the device  140  being managed and to be accessed, by analyzing an ARP request packet transmitted from the router  120 . Thereafter, the configuration management server  210  acquires the latest configuration information from the device  140  and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management server  210  and the actual configuration information of infrastructure devices occurs. The configuration management server  210  does not have to access another device when acquiring configuration information from the target device. Therefore, the load on the network is suppressed compared to a method of collecting configuration information through polling or the like. 
         [0094]      FIG. 15A  and  FIG. 15B  are sequence diagrams illustrating an example of processing of an information processing system according to a fourth embodiment. Like the information processing system  100  in  FIG. 11 , the information processing system according to the fourth embodiment includes the configuration management device  200  and the configuration management server  210  for the purpose of managing the devices  140 . The processing of the information processing system according to the fourth embodiment and the processing of the information processing system according to the third embodiment are the same in the process in S 101  to S 106  and in S 501  to S 503 . In the processing of the information processing system according to the fourth embodiment, the configuration management device  200  uses a GARP as an alternative to processing of deleting the ARP table  121  of the router  120 . An example of processing of the information processing system according to the fourth embodiment using a GARP packet will be described below. The process in S 101  to S 106  and S 501  to S 503  is similar to that in  FIG. 11  and the description thereof is omitted. 
         [0095]    The acquisition unit  211  of the configuration management server  210  transmits a request for acquiring the latest configuration information to the device  140   b  (S 701 ). The device  140   b  transmits the latest configuration information to the acquisition unit  211  of the configuration management server  210  (S 702 ). The acquisition unit  211  causes the configuration management DB  212  to reflect the acquired configuration information (S 703 ). 
         [0096]    Upon completion of the process in S 703 , the instruction unit  208  of the configuration management device  200  transmits the GARP packet  1  in order to update the ARP table  121  of the router  120  (S 704 ). The router  120  updates the ARP table  121  based on the received GARP packet  1  (S 705 ). The GARP packet  1  contains the IP address of the device  140   b  for which a change in setting has been made by the maintainer, and the MAC address of the configuration management device  200 . Thus, the IP address of the device  140   b  and the MAC address of the configuration management device  200  are set in association with each other in the ARP table  121  of the router  120 . Then, when, next, the maintainer attempts accessing the device  140   b  using ssh, an ssh message requesting ssh access is transferred to the configuration management device  200 . 
         [0097]    If there is access to the device  140   b  using ssh (the second time), the maintenance terminal  110  transmits an access request for the device  140   b  to the router  120  (S 706 ). The router  120  transmits an ssh message requesting access, to the configuration management device  200  (S 707 ). Upon detecting the request for access, the instruction unit  208  of the configuration management device  200  transmits the GARP packet  2  to the router  120  (S 708 ). The router  120  updates the ARP table  121  based on the received GARP packet  2  (S 709 ). The GARP packet  2  contains the IP address of the device  140   b  for which a change in setting has been made by the maintainer, and the MAC address of the device  140   b . Thus, the IP address of the device  140   b  and the MAC address of the device  140   b  are stored in association with each other in the ARP table  121  of the router  120 . Since the access request in S 706  does not result in access to the device  140   b , the maintenance terminal  110  fails in processing and times out. 
         [0098]    The maintenance terminal  110  transmits an access request for the device  140   b  to the router  120  by retry processing (S 710 ). The router  120 , upon acquiring the MAC address of the device  140   b , establishes a session from the maintenance terminal  110  to the device  140   b  (S 711 ). The maintainer changes the configuration of the device  140   b  through the maintenance terminal  110  (S 712 ). 
         [0099]    The configuration management device  200 , upon receiving the ssh message in S 707 , starts execution of the process in and after S 713  in parallel to the process in S 709  and so on. The determination unit  202  of the configuration management device  200  analyzes the received ssh message and determines whether or not the transmission source is the router  120  (S 713 ). The ssh message contains the IP addresses of the transmission source router  120  and the device  140  to be accessed. The determination unit  202  analyzes the IP address of the transmission destination in the ssh message. Then, the determination unit  202  determines whether or not the device  140   b  serving as the destination is a device being managed by the configuration management device  200  (S 714 ). 
         [0100]    The instruction unit  208  notifies the acquisition unit  211  of the configuration management server  210  of the IP address of the device  140   b  accessed (S 715 ). The process in S 715  is executed by the instruction unit  208  after the instruction unit  208  has been in a standby state for a given period of time after the process in S 714 . The acquisition unit  211  of the configuration management server  210  transmits a request for acquiring the latest configuration information to the device  140   b  (S 716 ). The device  140   b  transmits the latest configuration information to the acquisition unit  211  of the configuration management server  210  (S 717 ). The acquisition unit  211  causes the configuration management DB  212  to reflect the acquired configuration information (S 718 ). 
         [0101]    Through the process in S 701  to S 718 , the process as in the third embodiment may be executed without deleting or initializing the ARP table  121 . The configuration management device  200  may detect that a configuration change will be made for the device  140  being managed and to be accessed, by analyzing an ssh message transmitted from the router  120 . Thereafter, the configuration management device  200  acquires the latest configuration information from the device  140  and thus may reduce the period of time during which inconsistency between the configuration information managed by the configuration management system and the actual configuration information of infrastructure devices occurs. 
         [0102]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.