Abstract:
According to an aspect of an embodiment, a communication system comprises: a. a first information processing device; b. a first communication line and a first backup line connected to the first information processing device, respectively; c. a second information processing device; d. a second communication line and second backup line connected to the second information processing device, respectively; e. a first switch comprising: a first port connected to the first communication line; a second port connected to the second backup line; and a controller for performing of: detecting a failure of the first port; switching the second backup line; and sending a notification; and f. a second switch comprising: a third port connected to the first backup line; a fourth port connected to the second communication line; and a controller for performing of: receiving the notification; switching the first backup line and the second communication line.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This art relates to a switching system with a redundant configuration. 
         [0003]    2. Description of the Related Art 
         [0004]    For the purpose of ensuring communication reliability, a switch such as a router has a redundant configuration. In the actual operation, the router has a redundant configuration using a VRRP (Virtual Router Redundancy Protocol). Further, in order to effectively use resources such as a CPU and a memory in the switch, a switching system has a so-called Active-Active configuration. The Active-Active configuration is obtained by multiplexing a VRID of the VRRP, in which a plurality of routers with the redundant configuration communicate data. Herein, the VRID is an identifier that identifies a group of virtual routers at the VRRP. 
         [0005]    However, even if the switching system with the redundant configuration has the Active-Active configuration, upon causing a fault in one switch, there is a problem that the communication load is caused in another switch. 
         [0006]    Further, there is the following Japanese Laid-open Patent Publication No. 2003-318933, as a patent document, with respect to the switching system. 
       SUMMARY 
       [0007]    According to an aspect of an embodiment, a communication system comprises: a. a first information processing device; b. a first communication line and a first backup line connected to the first information processing device, respectively; c. a second information processing device; d. a second communication line and second backup line connected to the second information processing device, respectively; e. a first switch comprising: a first port connected to the first communication line; a second port connected to the second backup line; and a controller for performing of: detecting a failure of the first port; switching the second backup line; and sending a notification; and f. a second switch comprising: a third port connected to the first backup line; a fourth port connected to the second communication line; and a controller for performing of: receiving the notification; switching the first backup line and the second communication line. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a diagram showing the structure of a switching system with a redundant configuration according to the embodiment. 
           [0009]      FIG. 2  is a diagram showing the structure of a switching system for simultaneous operation of UPLINK and DOWNLINK according to the embodiment. 
           [0010]      FIG. 3  is a diagram showing the structure of a switching system to prevent the bias of the redundant configuration according to the embodiment. 
           [0011]      FIG. 4  is a diagram showing the structure of a switching system according to the embodiment. 
           [0012]      FIG. 5  is a schematic diagram showing grouping of ports included in a switch according to the embodiment. 
           [0013]      FIG. 6  is a diagram showing a sequence flow for defining the redundant configuration of a virtual switch according to the embodiment. 
           [0014]      FIG. 7  is a diagram showing a sequence flow for switching a route according to the embodiment. 
           [0015]      FIG. 8  is a diagram showing a sequence flow for linking operation of the virtual switch according to the embodiment. 
           [0016]      FIG. 9  is a diagram showing an operation sequence flow of a mode for increasing the number of VLANs according to the embodiment. 
           [0017]      FIG. 10  is a diagram showing a sequence flow for a retrieving function of a DOWNLINK group at a fault timing according to the embodiment. 
           [0018]      FIG. 11  is a diagram showing a physical adaptor management table according to the present invention. 
           [0019]      FIG. 12  is a block diagram showing the hardware of a switch according to the embodiment. 
           [0020]      FIG. 13  is a diagram showing the structure of a switching system to prevent the bias of the redundant configuration according to the embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]      FIG. 1  is a diagram showing the structure of a switching system  100  with a redundant configuration according to an embodiment. 
         [0022]    The switching system  100  comprises: switches  101  to  106 ; and personal computers (PCs)  107  to  118 . The personal computers  107  to  110  are connected to the switch  104 . Similarly, the personal computers  111  to  114  are connected to the switch  105 , and the personal computers  115  to  118  are connected to the switch  106 . According to the embodiment, the switches  101  and  103  have the redundant configuration. Further, the redundant configuration of the switches  101  and  103  is the Active-Active configuration using a VRRP. With the Active-Active configuration of the switches  101  and  103  using the VRRP, VLANs that can be individually used by the switches  101  and  103  are partly assigned to virtual switches identified by VRIDs. Furthermore, other virtual switches identified by VRIDs are assigned to other VLANs that can be individually used by the switches  101  and  103 . Physically, the switches  101  and  103  operate together with each other by network communication. Herein, the VRRP is a protocol for multiplexing a router. Further, the VRID is an identifier that identifies a group of virtual routers of the VRRP. 
         [0023]    Further, for a VLAN (Virtual Local Area Network), a function of network devices such as the switches  101  to  106  structures a virtual network in accordance with an MAC address, an IP address, and a protocol, independently of physical connection, and further groups terminals. Furthermore, according to the embodiment, the terminal means a device, a computer, and software that are dedicated to a user interface (I/F) for operating the computer, including the personal computers  107  to  118 . 
         [0024]    In addition, the switches  101  and  103  have the Active-Active configuration, thereby effectively using resources such as CPUs and memories of the switches  101  and  103 . That is, via a part of the VLANs according to the embodiment, communication is performed via the switch  101 , and communication is also performed via the switch  103  via other VLANs. Therefore, the number of VLANs assigned to CPUs and memories of the switches  101  and  103  may be small. 
         [0025]    The personal computers  107  to  110  form a VLAN  121 . Similarly, the personal computers  111  to  114  form a VLAN  122 , and the personal computers  115  to  118  form a VLAN  123 . 
         [0026]    The VLAN  121  executes communication via the redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  101  to Active and for setting the switch  103  to Standby. Further, the VLANs  122  and  123  execute the communication via the redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  101  to Standby and for setting the switch  103  to Active. The VLANs  122  and  123  form groups  119  and  120 , and switch the Active-Standby configuration of the switches  101  and  103  on the basis of the unit of the groups  119  and  120 . Furthermore, the switches  101  and  103  have a shut-down trigger function. The shut-down trigger function shuts-down even a link port in association with the down-operation of the port when there is a fault in any of monitored ports. According to the embodiment, the link port corresponds to a plurality of ports connected to a plurality of lines forming the group  119  and a plurality of ports connected to a plurality of lines forming the group  120 . For example, when a communication fault is caused between the VLAN  123  and the switch  103 , the switch  103  shuts-down the port used for communication with the VLAN  122  by using the shut-down trigger function. Upon switching the virtual router of the VRRP, the virtual switch can expand the operation of the VRRP with the down-operation of any of ports as a trigger. In addition, the virtual switch used for communication by the VLAN  121  and the virtual switches used for communication by the VLANs  122  and  123  are identified by the VRIDs, and the switches  101  and  103  identify the virtual switches by using the VRIDs thereof. 
         [0027]    Further, the personal computers  115  to  118  are shut-down with the shut-down trigger function of the virtual switch used for communication by the VLAN  122 , and the shut-down trigger function of the virtual switch used for communication by the VLAN  123  is set to the down-operation of the personal computers  111  to  114 . Thus, if a fault is caused in one virtual switch, another virtual switch is also switched. As a consequence, it is possible to synchronize the Active operation and the Standby operation of the groups  119  and  120 . 
         [0028]      FIG. 2  is a diagram showing the structure of a switching system  200  for simultaneous operation of UPLINK and DOWNLINK according to the embodiment. 
         [0029]    The switching system  200  comprises: switches  201  to  208 ; and the personal computers (PCs)  209  to  220 . The personal computers  209  to  212  are connected to the switch  206 . Similarly, the personal computers  213  to  216  are connected to the switch  207 , and the personal computers  217  to  220  are connected to the switch  208 . According to the embodiment, the switches  201  and  205  have the redundant configuration. Further, the redundant configurations of the switches  201  and  205  are the Active-Active configurations using the VRRPs. With the Active-Active configuration of the switches  201  and  205  using the VRRP, VLANs that can be individually used by the switches  201  to  205  are partly assigned to virtual routers identified by the VRIDs, and other virtual routers identified by the VRIDs are assigned to other VLANs. As a consequence, with the Active-Active configuration, the switches  201  to  205  are physically operated together with network communication. 
         [0030]    For a VLAN  223  according to the embodiment, communication is performed via the switch  201 , communication is performed via the switch  205  for VLANs  224  and  225 , and the number of VLANs assigned to CPUs and memories of the switches  201  to  205  may be small. 
         [0031]    The personal computers  209  to  212  form the VLAN  223 . Similarly, the personal computers  213  to  216  form the VLAN  224 , and the personal computers  217  to  220  form the VLAN  225 . 
         [0032]    The VLAN  223  performs communication via the redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  201  to Active (a route  227  is Active) and for setting the switch  205  to Standby (a route  228  is Standby). Further, the VLANs  224  and  225  perform communication via a redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  201  to Standby (a route of a group  221  is Standby) and for setting the switch  205  to Active (a route of a group  222  is Active). The redundant configuration of the virtual switches is set to the VLAN  224  and the VLAN  225 . Thus, if a fault is caused in one virtual switch, another virtual switch is also switched. Thus, the Active operation and the Standby operation of the groups  119  and  120  can be synchronized. 
         [0033]    Subsequently, a network portion comprising the switches  202  and  204  is referred to as an UPLINK  226 , and a network portion comprising the switches  201  and  205  is referred to as a DOWNLINK  227 . The switches  202  and  204  also have the Active-Active configuration using the VRRP, and form the redundant configuration. A route  229  to the switch  201  with respect to the switch  202  is Active, and a route  230  to the switch  205  with respect to the switch  202  is Standby. Similarly, a route  231  to the switch  201  with respect to the switch  204  is Standby, and a route  232  to the switch  205  with respect to the switch  204  is Active. 
         [0034]    With the redundant configuration of the UPLINK  226  and the DOWNLINK  227 , the routes used for communication are simultaneously switched. That is, if switching a communication route of the VLAN  223  in the DOWNLINK  227  from the route  227  to the route  228 , a communication route in the UPLINK  226  is simultaneously switched from the route  229  to the route  230 . Further, if switching communication routes of the VLANs  224  and  225  in the DOWNLINK  227  from routes of the group  222  to routes of the group  221 , a communication route in the UPLINK  226  is simultaneously switched from the route  232  to the route  231 . 
         [0035]    Then, it is assumed that a fault is caused in the network. If the switch  204  is troubled, the VLANs  224  and  225  in the UPLINK perform the communication via the routes  231  and  232  even via any of the switches  201  to  205 , thereby disabling the communication. Therefore, according to the embodiment, if the fault is caused in the switch  204 , the communication in the UPLINK  226  uses the switch  202  via the routes  229  and  230 . That is, the VLANs  224  and  225  switch the routes  231  and  232  in the UPLINK  226  to the routes  229  and  230  similarly to the VLAN  223 . At a timing for switching the group of the routes in the UPLINK  226 , it is detected that the Standby routes simultaneously operated in the UPLINK  226  are not switched to Active even if switching the route in the DOWNLINK  227 . Thus, if causing the fault in a switch such as a switch structuring the network, the communication can continue by the switching operation to the switch having the redundant configuration. 
         [0036]      FIG. 3  is a diagram showing the structure of a switching system  300  that prevents the bias of the redundant configuration that according to the embodiment. 
         [0037]    In the switching system  300  according to the embodiment, with the Active-Active redundant configuration, the load upon efficiently using the CPUs and memories of switches  301  and  303  is distributed. 
         [0038]    The switching system  300  comprises: the switches  301  and  303  and switches  302 ,  304 , and  305 ; and personal computers (PCs)  306  to  313 . The personal computers  306  to  309  are connected to the switch  304 . Similarly, the personal computers  310  to  313  are connected to the switch  305 . 
         [0039]    According to the embodiment, the switches  301  and  303  have the redundant configuration. Further, the redundant configurations of the switches  301  and  303  are the Active-Active configurations using the VRRPs. The personal computers  306  to  309  form a VLAN  318 . Similarly, the personal computers  310  to  313  form a VLAN  319 . 
         [0040]    The VLAN  318  performs communication via a redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  301  to Active (a route  314  is Active) and for setting the switch  302  to Standby (a route  316  is Standby). Further, the VLAN  319  performs communication via a redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  301  to Standby (a route  315  is Standby) and for setting the switch  303  to Active (a route  317  is Active). The virtual switch used for communication by the VLAN  318  and the virtual switch used for communication by the VLAN  319  are identified by using VRIDs, and the switches  301  and  303  identify the virtual switches by using the VRIDs thereof. 
         [0041]    Moreover, in the switching system  300  according to the embodiment, the virtual switches used for communication by the VLANs  318  and  319  switch the routes with the simultaneous operation. Thus, the switching system  300  can prevent the bias of the redundant configuration of the switches  301  and  303 . 
         [0042]    For example, if a fault is caused in the route  314  and a communication route of the VLAN  318  is switched from the route  314  to the route  316 , the routes  315  and  317  are simultaneously switched. As a consequence, the switches  301  and  303  can be physically used. Similarly, if the fault is caused in the route  314  and a communication route of the VLAN  318  is switched from the route  314  to the route  316 , the routes  315  and  317  are switched. 
         [0043]    A description will be given of another switching system  1300  to prevent the bias of the redundant configuration.  FIG. 13  is a diagram showing the structure of the switching system  1300  to prevent the bias of the redundant configuration according to the embodiment. 
         [0044]    Also in the switching system  1300  according to the embodiment, with the Active-Active redundant configuration, the load upon effectively using resources such as the CPUs and memories of the switches  301  and  303  is distributed. 
         [0045]    The switching system  1300  comprises: the switch  301  to  305 ; and the personal computers (PCs)  306  to  313 . The personal computers  306  to  309  are connected to the switch  304 . Similarly, the personal computers  310  to  313  are connected to the switch  305 . 
         [0046]    According to the embodiment, the switches  301  and  303  have the redundant configuration. Further, the redundant configurations of the switches  301  and  303  are the Active-Active configuration using the VRRPs. The personal computers  306  to  309  form the VLAN  318 . Similarly, the personal computers  310  to  313  form the VLAN  319 . 
         [0047]    According to the embodiment, the switch  301  and the switch  303  form a virtual switch for setting a group  1301  to the Active route and for using a group  1303  to the Standby route for communication of a part of the VLAN  318  and a part of the VLAN  319 , and a virtual switch for setting a group  1304  to the Active route and for using a group  1302  to the Standby route for communication of a part of the VLAN  318  and a part of the VLAN  319 . 
         [0048]    Further, in the switching system  1300  according to the embodiment, the virtual switches switch the routes used for communication by the VLAN  318  and the VLAN  319  with simultaneous operation. That is, if one virtual switch switches the Active route and the Standby route, at this switching timing of the routes, the other virtual switch switches the Active route and the Standby route. Thus, the switching system  300  realizes the prevention of the bias of the redundant configuration of the switches  301  and  303 . 
         [0049]    If a fault is caused in the route belonging to the group  1301 , the shut-down trigger function sets all the remaining routes belonging to the group  1301  to the Standby routes. Further, the switch  303  sets the group  1303  to the Active route. Furthermore, the switches  301  and  303  respectively set the groups  1302  and  1304  to the Active route and the Standby route, at this switching timing of the routes in the groups  1301  and  1303 . As a consequence, the switches  301  and  303  can be continuously physically used. 
         [0050]      FIG. 4  is a diagram showing the structure of a switching system  400  according to the embodiment. 
         [0051]    Herein, a description will be given of the number of VLANs used by the switching system  400  and a function for increasing the number of authentications corresponding to terminals forming the VLAN. Herein, the number of VLANs indicates the number of VLANs included in the switching system  400 , and the number of authentications indicates the number of identifiers corresponding to the terminals forming the VLAN. 
         [0052]    The switching system  400  comprises: switches  401  to  405 ; and personal computers (PCs)  406  to  413 . The personal computers  406  to  409  are connected to the switch  404 . Similarly, the personal computers  410  to  413  are connected to the switch  405 . 
         [0053]    According to the embodiment, the switches  401  and  403  have the redundant configuration. Further, the redundant configurations of the switches  401  and  403  have the Active-Active configurations using the VRRPs. The personal computers  406  to  409  form a VLAN  418 . Similarly, the personal computers  410  to  413  form a VLAN  419 . 
         [0054]    The VLAN  418  performs communication via the redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  401  to Active (a route  414  is Active) and for setting the switch  402  to Standby (a route  416  is Standby). Further, the VLAN  419  performs communication via the redundant configuration (Active-Standby configuration) of a virtual switch for setting the switch  401  to Standby (a route  415  is Standby) and for setting the switch  403  to Active (a route  417  is Active). The virtual switch used for communication by the VLAN  418  and the virtual switch used for communication by the VLAN  419  are identified by VRIDs, and the switches  401  and  403  identify the virtual switches with the VRIDs thereof. 
         [0055]    A route via the switch  402  between the switches  401  and  402  can be set as a monitoring path  420  for periodically monitoring the switching operation of communication routes thereof. 
         [0056]    Further, if a fault is caused in the route  414  of the VLAN  418 , the switches  410  and  403  switch a communication route of the VLAN  418  from the route  414  to the route  416  serving as a Standby route. In other words, the VLAN  418  is assigned to the switch  403 . The switches  401  and  403  detect that the communication route used by the VLAN  418  is switched from the route  414  to the route  416  via the monitoring path  420 . Further, the switches  410  and  403  switch the communication route of the VLAN  419  from the route  417  to the route  415  serving as the Standby route. In other words, the VLAN  419  is assigned to the switch  401 . Accordingly, the switch physically used for communication by the VLAN  418  is the switch  403  and the switch used for communication by the VLAN  419  is the switch  401 . Therefore, it is possible to efficiently use resources such as CPUs and memories of the switches  401  and  403 . Further, the number of VLANs used by the switching system  400  can be increased with the switching operation of the routes of the switches  401  and  403  and the switching and resetting operation of the VLANs assigned to the switches  401  and  403 . 
         [0057]    In general, the number of VLANs used by the VRRP is 4,096 at the maximum level. In the actual standard of the switch, the number of VLANs has the upper limit not-more-than 4,096 in many cases, e.g., the maximum number of used VLANs is 60 or 120. Further, according to the embodiment, at the switching timing of the communication routes, the VLAN  418  used by the switch  401  and the VLAN  419  used by the switch  403  are switched. Thus, the switches  401  and  403  can maximally use the number of used VLANs. If the number of VLANs is 4,096 or less and the VLANs are individually assigned to the switches, the number of VLANs used by the switching system can be increased. Further, if requiring 4,096 or more VLANs like wire-area Ethernet (registered trademark), the number of used VLANs is 4,096 or more by adding an identifier to a VLAN ID of one switch in the switching system with the redundant configuration. Furthermore, in the switching system  400  according to the embodiment, the increase in the number of VLANs enables the number of authentications used for identification of the personal computers  406  to  413 . 
         [0058]    Moreover, according to the embodiment, the ports included in the switch are grouped, thereby forming the virtual switch. In addition, the switching processing performed by the virtual switch is linked by monitoring LINKUP and LINKDOWN in another group of virtual switches with the redundant configuration. 
         [0059]      FIG. 5  is a schematic diagram showing the grouping of the ports included in the switch  401  according to the embodiment. 
         [0060]    The switch  401  comprises ports  501  to  507 . The ports  501  and  502  are assigned to the VLAN  418 , the port  503  is assigned to the VLAN  419 , and the ports  501 ,  505 ,  506 , and  507  are assigned to a VLAN  500 . The VLAN  500  is formed by the switch  402  and the switches  401  and  403 . The switch  401  groups the ports  501  to  507  corresponding to the individual VLANs  418 ,  419 , and  500 . The switch  401  manages group information  1103  of a redundant-configured virtual switch indicating the ports  501  and  502  as a group  51 , the port  503  as a group  52 , and the ports  504  to  507  as a group  53 . 
         [0061]      FIG. 6  is a diagram showing a sequence flow for defining the redundant configuration of the virtual switch according to the embodiment. 
         [0062]    With the following sequence, in the switching system  400 , it is defined that the Active-Active configurations of the switches  401  and  403  have the redundant configurations. 
         [0063]    First, from among the ports included in the switch  401 , the switch  401  groups the ports used for communication by the VLAN  418 , and adds a group ID to the group (in step S 601 ). The switch  401  sets a virtual switch IP for identifying a virtual switch  61  used for communication by the VLAN  418  (in step S 602 ). According to the embodiment, the virtual switch ID of the virtual switch  61  used for communication by the VLAN  418  and the group ID of the port used for communication by the VLAN  418  have a one-to-one corresponding relationship. However, the virtual switch  61  can use a plurality of groups. In other words, a plurality of the group IDs can correspond to the virtual switch IP. A Primary IP and a Secondary IP for identifying the Active route  414  and the Standby route  416  of the virtual switch  61  used for communication by the VLAN  418  are set (in step S 603 ). The Primary IP indicates the Active route  414  and the Secondary IP denotes the Standby route  416 . Further, the switch  401  sets the monitoring path  420  that monitors the switching operation of the communication route of the virtual switch  62  used for communication by the VLAN  419  (in step S 604 ). Subsequently, the switch  401  monitors the switching operation of the route in the virtual switch  62  and the link state of the virtual switch  61  and the virtual switch  62  via the set monitoring path  420  (in step S 605 ). 
         [0064]    Similarly, the switch  403  groups the ports used for communication by the VLAN  419  from among the ports included in the switch  403 , and adds the group ID to the group (in step S 606 ). The switch  403  sets the virtual switch IP for identifying the virtual switch  62  used for communication by the VLAN  419  (in step S 607 ). According to the embodiment, the virtual switch ID of the virtual switch  62  used for communication by the VLAN  419  and the group ID of the port used for communication by the VLAN  419  have a one-to-one corresponding relationship. However, the virtual switch  62  can use a plurality of groups. In other words, a plurality of the group IDs can correspond to the virtual switch IP. A Primary IP and a Secondary IP for identifying the Active route  417  and the Standby route  415  of the virtual switch  62  used for communication by the VLAN  419  are set (in step S 608 ). The Primary IP denotes the Active route  417  and the Secondary IP denotes the Standby route  415 . Further, the switch  403  sets the monitoring path  420  that monitors the switching operation of the communication route of the virtual switch  62  used for communication by the VLAN  403  (in step S 609 ). Subsequently, the switch  401  monitors the switching operation of the route in the virtual switch  62  and the link state of the virtual switch  61  and the virtual switch  62  via the set monitoring path  420  (in step S 610 ). 
         [0065]    Subsequently, the virtual switches  61  and  62  start synchronous processing (in step S 611 ). In the synchronous processing, the switches  401  and  403  form the virtual switches  61  and  62  and communicate data between the VLANs  418  and  419  via the monitoring path  420  while monitoring the switching operation of the VLANs  418  and  419 . 
         [0066]    Subsequently, the switches  401  and  403  determine whether or not the number of the group IDs assigned to the virtual switch  61  by the switch  401  is equal to the number of the group IDs assigned to the virtual switch  62  by the switch  403 , and whether or not the number of ports assigned to the virtual switch  61  by the switch  401  is equal to the number of ports assigned to the virtual switch  62  by the switch  403  (in step S 612 ). If it is determined that at least one of the number of the group IDs and the number of ports therebetween does not match each other, it is determined that the redundant configuration is not possible (in step S 613 ). 
         [0067]    If it is determined that both of the number of the group IDs and the number of ports therebetween individually match those, the switches  401  and  403  determine whether or not the link state of the ports assigned to the monitoring path  420  by the switches  401  and  403  is UP (in step S 614 ). The UP-link state means that the switches  401  and  403  can monitor themselves each other via the monitoring path  420 . If the switches  401  and  403  determine that the link state of the ports assigned to the monitoring path  420  is not UP (is i.e., DOWN), it is determined that the redundant configuration is not possible (in step S 613 ). 
         [0068]    When the switches  401  and  403  determine that the link state of the ports assigned to the monitoring path  420  is UP, it is determined whether or not the switches  401  and  403  are at the start time (in step S 615 ). 
         [0069]    When it is determined that the switches  401  and  403  are at the start time, it is determined whether or not the Active routes  414  and  417  are DOWN (in step S 616 ). When it is determined that the switches  401  and  403  are not DOWN, the routes  414  and  417  are set to Active and the routes  415  and  416  are set to Standby (in step S 618 ). When it is determined that the switches  401  and  403  are DOWN, the routes  414  and  417  are set to Standby and the routes  415  and  416  are set to Active (in step S 619 ). 
         [0070]    When it is determined that the switches  401  and  403  are not at the start time, it is determined whether or not the end of the start operation of the switch  401  is earlier than the end of the start operation of the switch  403  (in step S 617 ). 
         [0071]    When the switches  401  and  403  determine that the end of the start operation of the switch  401  is earlier than the end of the start operation of the switch  403 , the routes  414  and  417  are set to Active and the routes  415  and  416  are set to Standby (in step S 618 ). When the switches  401  and  403  determine that the end of the start operation of the switch  403  is earlier than the end of the start operation of the switch  401 , the routes  414  and  417  are set to Standby and the routes  415  and  416  are set to Active (in step S 619 ). 
         [0072]      FIG. 7  is a diagram showing a sequence flow for switching the route according to the embodiment. 
         [0073]    In the diagram of the sequence flow, when a fault is caused in any of the Active routes  414  and  417 , the routes in the switches  401  and  403  are switched. Hereinbelow, a description will be given of the processing for switching the route when a fault is caused in the Active route  414 . 
         [0074]    The fault is caused in any of the ports used for the Active route  414  (in step S 701 ). The switch  401  performs processing for switching the route  414  to Standby (in step S 702 ). The switch  401  sets the monitoring path  420  for monitoring the switching operation of the communication route of the virtual switch  62  used for communication by the VLAN  419  (in step S 703 ). The switch  401  switches the route of the virtual switch  62 , and monitors the link state between the virtual switches  61  and  62  via the set monitoring path  420  (in step S 704 ). Further, when the monitoring path  420  has been already set or when the set monitoring path is normal, the switches  401  and  403  do not set the monitoring path  420  again. 
         [0075]    The switch  403  receives link-down information indicating that the fault is caused in any of the ports used for the Active route  414  from the switch  401  (in step S 705 ). When the monitoring path  420  is normal, the switches  401  and  403  receive and transmit the link-down information by using the monitoring path  420 . When the monitoring path  420  does not exist or is DOWN, the switches  401  and  403  receive and transmit the link-down information by using the routes  415  and  417 . The switch  403  performs processing for switching the route  416  to Active (in step S 706 ). The switch  403  sets the monitoring path  420  for monitoring the switching operation of the communication route of the virtual switch  62  used for communication by the VLAN  418  (in step S 707 ). The switch  403  switches the route of the virtual switch  61 , and monitors the link state between the virtual switches  61  and  62  via the set monitoring path  420  (in step S 708 ). 
         [0076]    Further, the virtual switches  61  and  62  start the synchronous processing (in step S 709 ). In the synchronous processing, the switches  401  and  403  form the virtual switches  61  and  62  and communicate data between the VLANs  418  and  419  via the monitoring path  420  while monitoring the switching operation of the communication route thereof. 
         [0077]    Furthermore, the switches  401  and  403  determine whether or not the number of the group IDs assigned to the virtual switch  61  by the switch  401  is equal to the number of the group IDs assigned to the virtual switch  62  by the switch  403 , and whether or not the number of ports assigned to the virtual switch  61  by the switch  401  is equal to the number of ports assigned to the virtual switch  62  by the switch  403  (in step S 710 ). When at least one of the number of the group IDs and the number of ports does not match each other, it is determined that the redundant configuration is not possible (in step S 711 ). 
         [0078]    When both the number of the group IDs and the number of the ports individually match those, the switches  401  and  403  determine whether or not the link state of the ports assigned to the monitoring path  420  by the switches  401  and  403  is UP (in step S 712 ). In the UP-link state, the switches  401  and  403  can monitor each other via the monitoring path  420 . When it is determined that the link state of the ports assigned to the monitoring path  420  by the switches  401  and  403  is not UP (i.e., is DOWN), it is determined that the redundant configuration is not possible (in step S 711 ). 
         [0079]    When it is determined that the link state of the ports assigned to the monitoring path  420  by the switches  401  and  403  is UP, it is determined whether or not the switches  401  and  403  are at the start time (in step S 713 ). 
         [0080]    When it is determined that the switches  401  and  403  are at the start time, it is determined whether or not the Active routes  414  and  417  are DOWN (in step S 714 ). When it is determined that the switches  401  and  403  are not DOWN, the routes  414  and  417  are set to Active and the routes  415  and  416  are set to Standby (in step S 716 ). When it is determined that the switches  401  and  403  are DOWN, the routes  414  and  417  are set to Standby and the routes  415  and  416  are set to Active (in step S 717 ). 
         [0081]    When it is determined that the switches  401  and  403  are not at the start time, it is determined whether or not the end of the start operation of the switch  401  is earlier than the end of the start operation of the switch  403  (in step S 715 ). 
         [0082]    When the switches  401  and  403  determine that the end of the start operation of the switch  401  is earlier than the end of the start operation of the switch  403 , the routes  414  and  417  are set to Active and the routes  415  and  416  are set to Standby (in step S 716 ). When the switches  401  and  403  determine that the end of the start operation of the switch  403  is earlier than the end of the start operation of the switch  401 , the routes  414  and  417  are set to Standby and the routes  415  and  416  are set to Active (in step S 717 ). 
         [0083]      FIG. 8  is a diagram showing a sequence flow of the link operation of the virtual switch according to the embodiment. 
         [0084]    First, the switches  401  and  403  designate the virtual switches that are switched with the link operation (in steps S 801 , S 806 , S 811 , and S 816 ). Herein, the virtual switches are the virtual switch  61  comprising the routes  414  and  416  and the virtual switch  62  comprising the routes  415  and  417 . 
         [0085]    Further, the switch  401  sets the route  414  to the Active route of the virtual switch  61  (in step S 802 ). Further, the switch  403  sets the route  416  to the Standby route of the virtual switch  61  (in step S 807 ). Similarly, the switch  401  sets the route  415  to the Active route of the virtual switch  62  (in step S 812 ), and the switch  403  sets to the route  417  to the Standby route of the virtual switch  62  (in step S 817 ). 
         [0086]    Further, any of the ports in the switch  401  connected to the route  414  is DOWN (in step S 803 ). The virtual switch  61  performs switching processing for switching the route  414  to the Standby route (in step S 804 ), and the route  414  becomes the Standby route (in step S 805 ). 
         [0087]    Further, the switch  403  receives link-down information indicating that any of the ports in the switch  401  connected to the route  414  is DOWN (in step S 808 ). Furthermore, the virtual switch  61  performs switching processing for switching the route  416  to the Active route (in step S 809 ), and the route  416  becomes the Active route (in step S 810 ). 
         [0088]    Further, the switch  403  receives an instruction for switching the link operation via the monitoring path  420 , and transmits a notification indicating that the route  417  is switched to the Standby route to the switch  401  (in step S 813 ). The virtual switch  62  performs switching processing for switching the route  417  to the Standby route (in step S 814 ), and the route  417  becomes the Standby route (in step S 815 ). 
         [0089]    Further, the switch  401  receives the switching notification indicating that the route  417  is switched to Standby from the switch  403  (in step S 818 ). Furthermore, the virtual switch  62  performs switching processing for switching the route  415  to the Active route (in step S 819 ), and the route  415  becomes the Active route (in step S 820 ). 
         [0090]      FIG. 9  is a diagram showing an operation sequence of a mode for increasing the number of VLANs according to the embodiment. 
         [0091]    First, the switches  401  and  403  designate the virtual switches that are switched with the link operation, and set the VLANs using the virtual switches thereof (in steps S 901 , S 907 , S 913 , and S 919 ). The virtual switches are the virtual switch  61  comprising the routes  414  and  416  and the virtual switch  62  comprising the routes  415  and  417 . The VLAN  418  performs communication via the virtual switch  61 , and the VLAN  419  performs communication via the virtual switch  62 . 
         [0092]    Further, the switch  401  sets the route  414  to the Active route of the virtual switch  61  (in step S 902 ). Furthermore, the switch  403  sets the route  416  to the Standby route of the virtual switch  61  (in step S 908 ). Similarly, the switch  401  sets the route  415  to the Active route of the virtual switch  62  (in step S 914 ), and the switch  403  sets the route  417  to the Standby route of the virtual switch  62  (in step S 920 ). 
         [0093]    Further, any of the ports of the switch  401  connected to the route  414  is DOWN (in step S 903 ). The switch  401  switches the VLAN to be used from the VLAN  418  to the VLAN  419  (in step S 904 ). The virtual switch  61  performs switching processing for switching the route  414  to the Standby route (in step S 905 ), and the route  414  becomes the Standby route (in step S 906 ). 
         [0094]    Further, the switch  403  receives link-down information indicating that any of the ports of the switch  401  connected to the route  414  is DOWN (in step S 909 ). The switch  403  sets the VLAN to be used from the VLAN  419  to the VLAN  418  (in step S 910 ). Furthermore, the virtual switch  61  performs switching processing for switching the route  416  to the Active route (in step S 911 ), and the route  416  becomes the Active route (in step S 912 ). 
         [0095]    In addition, the switch  403  receives a switching instruction of the link operation via the monitoring path  420 , and transmits, to the switch  401 , a notification indicating that the route  417  is switched to the Standby route (in step S 915 ). The switch  403  switches the VLAN to be used from the VLAN  419  to the VLAN  418  (in step S 916 ). The virtual switch  62  performs switching processing for switching the route  417  to the Standby route (in step S 917 ), and the route  417  becomes the Standby route (in step S 918 ). 
         [0096]    Further, the switch  401  receives a switching notification indicating that the route  417  is switched to Standby from the switch  403  (in step S 921 ). The switch  401  switches the VLAN to be used from the VLAN  418  to the VLAN  419  (in step S 922 ). Furthermore, the virtual switch  62  performs switching processing for switching the route  415  to the Active route (in step S 923 ), and the route  415  becomes the Active route (in step S 924 ). 
         [0097]      FIG. 10  is a diagram showing a sequence flow for a retrieving function of a DOWNLINK group at the time of a fault according to the embodiment. 
         [0098]    According to the embodiment, a description will be given of the diagram of the sequence flow by using the switching system  200  shown in  FIG. 2  as an example. 
         [0099]    First, the switches  201  and  205  designate the virtual switches that are switched with the link operation, and set the ports connected to the UPLINK  226  and DOWNLINK  227  (in steps S 1001 , S 1005 , S 1010 , and S 1014 ). Herein, the virtual switches are the virtual switch  1  comprising the paths  227  and  228  and the virtual switch  2  comprising the groups  221  and  222 . 
         [0100]    In addition, the switch  205  sets the route belonging to the group  222  to the Active route of the virtual switch  2  (in step S 1002 ), and the switch  201  sets the route belonging to the group  221  to the Standby route of the virtual switch  2  (in step S 1006 ). Similarly, the switch  201  sets the route  227  to the Active route of the virtual switch  1  (in step S 1011 ), and the switch  205  sets the route  228  to the Standby route of the virtual switch  1  (in step S 1015 ). 
         [0101]    Then, any of the ports of the switch  205  is DOWN (in step S 1003 ). The virtual switch  2  performs switching processing for switching the route belonging to the group  222  to the Standby route, and the route belonging to the group  222  becomes the Standby route (in step S 1004 ). 
         [0102]    Further, the switch  201  receives link-down information indicating that any of the ports of the switch  205  is DOWN (in step S 1007 ). A fault is caused in the switch  204  and the switch  205  determines that all the ports of the UPLINK  226  in the switch  205  are DOWN (in step S 1008 ). The virtual switch  2  continuously sets the route belonging to the group  221  to the Standby route (in step S 1009 ). 
         [0103]    Furthermore, the virtual switch  1  performs retrieving processing for retrieving the route belonging to the group  222  of the virtual switch  2  and the route  232  (in step S 1012 ). In addition, the virtual switch  1  continuously sets the route  227  to the Active route (in step S 1013 ). Similarly to the Standby route of the virtual switch  2 , the virtual switch  1  performs retrieving processing for retrieving the route belonging to the group  221  of the virtual switch  2  and the route  231  (in step S 1016 ). In addition, the virtual switch  1  continuously sets the route  228  to the Standby route (in step S 1017 ). 
         [0104]      FIG. 11  is a physical adaptor management table  1100 . 
         [0105]    The physical adaptor management table  1100  comprises: a physical adaptor identifier  1101 ; a VLAN link identifier  1102 ; the group information  1103  of the redundant-configured virtual switch; UPLINK group information  1104 ; DOWNLINK group information  1105 ; link information  1106 ; link-group correlating information  1107 ; group moving link information  1108 ; moving link correlating information  1109 ; information  1110  of a mode for increasing the number of VLANs; and information  1111  on a target group of the mode for increasing the number of VLANS. 
         [0106]    The physical adaptor identifier  1101  is an identification (ID) number (No.) added to a physical adaptor. The physical adaptor is a connecting portion to another information processing device of the port included in the switch. The VLAN link identifier  1102  is an ID No. that is assigned to the physical adaptor and indicates the VLAN to be linked. The group information  1103  of the redundant-configured virtual switch collects the physical adaptors and identifies the redundant-configured group. The UPLINK group information  1104  identifies the UPLINK group from among the redundant-configured virtual switches. The DOWNLINK group information  1105  identifies the DOWNLINK group from among the redundant-configured virtual switches. The link information  1106  indicates whether or not the link operation of the switching operation of the routes in the switching system is active. The link-group correlating information  1107  correlates, with each other, the groups for setting the switching operation of the link operation in the switching system to be active. The group moving link information  1108  indicates whether or not the correlated DOWNLINK group is shifted to another group upon causing a fault of the UPLINK group. The moving link correlating information  1109  correlates the groups for setting the link operation of the group movement with each other. According to the embodiment, the moving link correlating information  1109  relates only to the correlation within the DOWNLINK groups and the UPLINK groups. The information  1110  of the mode for increasing the number of VLANs indicates whether or not a function for increasing the number of VLANs is active. Herein, in the function for increasing the number of VLANs, the switching operation of the routes in the switching system is performed with the link operation, and even the VLAN assigned to the switch is switched. The information  1111  on the target group of the mode for increasing the number of VLANs correlates the groups for setting the function for increasing the number of VLANs to be active with each other. 
         [0107]      FIG. 12  is a block diagram showing the hardware of the switch  401  according to the embodiment. 
         [0108]    The switch  401  comprises: a control unit  1201 ; ports  1202 ,  1203 , and  1204 ; and a storage unit  1205 . 
         [0109]    The control unit  1201  comprises a CPU and a RAM, and variously controls the ports  1202 ,  1203 , and  1204  and the storage unit  1205 . The control operation is processed by executing an OS (Operating System) and a control program stored in the storage unit  1205 . The control unit  1201  performs switching processing of a communication route by starting the OS stored in the storage unit  1205 . Further, the OS performs processing for transmitting a packet received from the VLAN  418  to the switch  402 . 
         [0110]    The port  1202  is connected to the switch  402 . Further, the port  1203  is connected to the VLAN  419  via the switch  405 . The port  1204  is connected to the VLAN  418  via the switch  404 . The control unit  1201  controls the operation for receiving the packet from the VLAN  418  via the port  1204  and transmitting the receiving packet to the switch  402  via the port  1202 . Further, the control unit  1201  controls the operation for receiving the packet from the switch  402  via the port  1202  and transmitting the received packet to the VLAN  418  via the port  1204 . The control unit  1201  controls the operation for setting the route  415  connected to the port  1203  to the Standby route and setting the route  415  in a hot standby mode, and preventing the reception and transmission of the packet from/to the port  1203 . 
         [0111]    Further, when a fault is caused in the port  1204  and the communication via the port  1204  is not possible, the control unit  1201  enables the communication via the port  1203 . The control unit  1201  switches the VLAN  418  to the VLAN  419 . In addition, the control unit  1201  transmits, to the switch  403  via the port  1202 , link-down information indicating that the port  1204  is DOWN and a switching instruction of the link operation. The control unit of the switch  403  transmits, to the switch  401 , a notification indicating that the route  417  is switched to the Standby route on the basis of the switching instruction of the link operation received from the switch  401 . The control unit of the switch  403  switches the VLAN to be used from the VLAN  419  to the VLAN  418  and performs switching processing for switching the route  417  to the Standby route. 
         [0112]    The storage unit  1205  stores a program and application for controlling the switch  401 , such as the OS. Further, the storage unit  1205  stores a routing table, and the OS determines the transmitting destination of the packet received from the switch  401  by referring to the routing table and controls the transmission of the packet. 
         [0113]    With the above operation, the switching system according to the embodiment exhibits the following advantages and effectively realizes the redundant configuration of the switch. The switching system according to the embodiment has: 1. the function for increasing the number of VLANs; 2. the function for removing the bias at the fault time; and 3. the function using the route for preventing the communication at a double fault. 
         [0114]    In the switching system according to the embodiment, the Active-Active configuration using the VRRP enables the increase in the number of VLANs available by the switching system and in the number of authenticated users in proportion to the number of switches. Further, the consumption of a new bit field due to the increase in the number of VLANs is prevented. 
         [0115]    In addition, in the switching system according to the embodiment, even if causing a line fault, a port fault, or a LAN fault, the communication is kept without reducing the number of VLANs used by the switching system. 
         [0116]    In addition, in the switching system according to the embodiment, even if causing a port fault in the Active-Active configuration, the line using state can be equally kept without removing the bias in the switch used for communication. As a consequence, even at the time for causing the fault, the use of resources such as the CPU and the memory of the switch is effectively kept. 
         [0117]    In addition, in the switching system according to the embodiment, since switching a plurality of the virtual switches having the redundant configuration with the link operation, the route of the virtual switch in which the fault is caused is retrieved to the virtual switch in which the fault is not caused and the switching system withstanding a double fault is realized. 
         [0118]    Further, in the switching system according to the embodiment, the packet is transmitted and received by using the Active route in the virtual switch and the packet thus passes through the same route in outward and return and the time for receiving and transmitting the packet is reduced. As a consequence, a problem that SYN-ACK is deviated in the communication authentication and a program of the deviation of the packet permission in firewall are not caused. 
         [0119]    According to the present invention, the processing executed by the detecting means is included in the processing performed the control unit  1201  according to the embodiment. Further, according to the present invention, the processing performed by the switching means is also included in the processing executed by the control unit  1201 . In addition, according to the present invention, the notifying means is included in the processing executed by the control unit  1201 . 
         [0120]    Next, the technological spirits extracted from the switch according to the embodiment will be explained as appendixes in the description of Claims. The technological spirits according to the present invention can be grasped from the upper concept to the lower concept at various levels with variation thereof, and the present invention is not limited to the following appendixes.