Abstract:
A server includes a plurality of network interfaces capable of communicating between the server and a plurality of communication apparatus which includes network ports capable of connecting a communication cable; a first unit specifying a pair of the network ports, which are connected via the communication cable, according to information related to connectivity of the network ports; and a second unit sending an instruction to the communication apparatus; wherein the instruction is to connect a first end of the communication cable to a first port corresponds to the specified port, and to connect a second end of the communication cable to a second port corresponds to the specified port.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a Continuation application of U.S. patent application Ser. No. 13/580,623, filed on Aug. 22, 2012, which is based on International Application No. PCT/JP2011/053687 filed on Feb. 21, 2011, which is based on Japanese Patent Application No. 2010-035684 filed on Feb. 22, 2010, the entire contents of which are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a communication system provided with a plurality of communication equipments that are configured to be mutually connectable through a communication cable. 
       BACKGROUND ART 
       [0003]    There is known a communication system provided with: a plurality of communication equipments that are configured to be mutually connectable through a communication cable; and a server equipment that is communicatively connected to each of the plurality of communication equipments. 
         [0004]    As one of this sort of communication systems, in a communication system described in Patent literature 1, each of communication equipments is provided with a communication port that is detachably connected with a communication cable. Further, each of the communication equipments is provided with a light emitting diode that emits light when a connection (link) is established between a communication port provided for the device of interest and a communication port provided for another communication equipment (i.e., when the communication cable is connected). The light emitting diodes are arranged corresponding to the respective communication ports (near respective communication ports). 
         [0005]    According to this, by viewing emission states of the light emitting diodes, a user can easily recognize whether or not each of the communication ports is in a state of being communicable with another communication port. 
       CITATION LIST 
     Patent Literature 
       [0006]    Patent literature 1: JP2004-32308A 
       SUMMARY OF INVENTION 
       [0007]    However, in the above-mentioned communication system, when a user connects one end of a communication cable with a communication port, it is relatively difficult to identify a communication port to which the other end of the communication cable should be connected, which is a problem. 
         [0008]    Therefore, an object of the present invention is to provide a communication system that can solve the above-mentioned problem that “when a user connects one end of a communication cable to a communication port, it is hard to identify a communication port to which the other end of the communication cable should be connected”. 
         [0009]    In an aspect of the present invention, a communication system has: a plurality of communication equipments; and a server equipment communicatively connected to each of the plurality of communication equipments. Each of the plurality of communication equipments has: a communication port to which a communication cable is connected in a detachable manner; a connection notification transmitting unit; and a first notification unit. The connection notification transmitting unit transmits, to the server equipment, communication port identification information for identifying the communication port to which the communication cable is connected. The first notification unit indicates, in a viewable manner, a communication port corresponding to a first notification instruction received from the server equipment as a communication port to which the communication cable is required to be connected. The server equipment has a connection configuration information storage unit and a first notification instruction transmitting unit. The connection configuration information storage unit stores connection configuration information indicating a correspondence relationship between a pair of communication ports expected to be connected with each other though the communication cable and a connection status of the pair of communication ports and the communication cable. The first notification instruction transmitting unit refers to the connection configuration information corresponding to the communication port identification information received from any of the plurality of communication equipments, and transmits, if another communication port of the pair of communication ports other than the communication port corresponding to the communication port identification information is not yet connected to the communication cable, the first notification instruction for identifying the another communication port to a communication equipment having the another communication port. 
         [0010]    In another aspect of the present invention, a communication method includes: a step of retaining, by a server equipment, connection configuration information indicating a correspondence relationship between a pair of communication ports expected to be connected with each other though a communication cable and a connection status of the pair of communication ports and the communication cable; a step of transmitting, by a communication equipment, communication port identification information for identifying a communication port to which the communication cable is connected, to the server equipment, a step of referring, by the server equipment, to the connection configuration information corresponding to the communication port identification information and transmitting, if another communication port of the pair of communication ports other than the communication port corresponding to the communication port identification information is not yet connected to the communication cable, a first notification instruction for identifying the another communication port to another communication equipment having the another communication port; and a step of indicating in a viewable manner, by the another communication equipment, the another communication port corresponding to the first notification instruction as a communication port to which the communication cable is required to be connected. 
         [0011]    According to the present invention thus constructed, when one end of a communication cable is connected to a communication port, a user can easily identify a communication port to which the other end of the communication cable should be connected. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]    The above-described object, effect, and features will be more apparent from description of exemplary embodiments in conjunction with the accompanying drawings. 
           [0013]      FIG. 1  is a diagram representing a schematic configuration of a communication system according to a first exemplary embodiment of the present invention. 
           [0014]      FIG. 2  is a block diagram representing an outline of functions of the communication system according to the first exemplary embodiment of the present invention. 
           [0015]      FIG. 3  illustrates a connection configuration table stored in any of storage devices provided for a server equipment according to the first exemplary embodiment of the present invention. 
           [0016]      FIG. 4  illustrates a communication equipment identification table stored in any of the storage devices provided for the server equipment according to the first exemplary embodiment of the present invention. 
           [0017]      FIG. 5  is a sequence diagram illustrating operation of the communication system according to the first exemplary embodiment of the present invention. 
           [0018]      FIG. 6  is a flowchart illustrating a connection detection processing program executed by a communication equipment according to the first exemplary embodiment of the present invention. 
           [0019]      FIG. 7  is a flowchart illustrating a notification instruction transmission processing program executed by the server equipment according to the first exemplary embodiment of the present invention. 
           [0020]      FIG. 8  is a flowchart illustrating a first notification processing program executed by the communication equipment according to the first exemplary embodiment of the present invention. 
           [0021]      FIG. 9  is a flowchart illustrating a communication confirmation notification processing program executed by the communication equipment according to the first exemplary embodiment of the present invention. 
           [0022]      FIG. 10  is a flowchart illustrating a communication confirmation reception processing program executed by the server equipment according to the first exemplary embodiment of the present invention. 
           [0023]      FIG. 11  is a block diagram representing an outline of functions of a communication system according to a second exemplary embodiment of the present invention. 
           [0024]      FIG. 12  is a sequence diagram illustrating operation of the communication system according to the second exemplary embodiment of the present invention. 
           [0025]      FIG. 13  is a block diagram representing an outline of functions of a communication system according to a third exemplary embodiment of the present invention. 
           [0026]      FIG. 14  is a sequence diagram illustrating operation of a communication system according to a fourth exemplary embodiment of the present invention. 
           [0027]      FIG. 15  is a flowchart illustrating a connection detection processing program executed by a communication equipment according to the fourth exemplary embodiment of the present invention. 
           [0028]      FIG. 16  is a flowchart illustrating a notification instruction transmission processing program executed by a server equipment according to the fourth exemplary embodiment of the present invention. 
           [0029]      FIG. 17  is a flowchart illustrating a communication confirmation reception processing program executed by the server equipment according to the first exemplary embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    Respective exemplary embodiments of a communication system, a communication method, a server equipment, a program, and a communication equipment according to the present invention will hereinafter be described referring to  FIGS. 1 to 17 . 
       First Exemplary Embodiment 
     Configuration 
       [0031]    As illustrated in  FIG. 1 , a communication system  1  according to a first exemplary embodiment includes: a server equipment  10 ; and a plurality of communication equipments  20   a ,  20   b , . . . . In the present example, each of the communication equipments  20   a ,  20   b , . . . is a relay device (such as a switch or a router) that relays communication. Alternatively, each of the communication equipments  20   a ,  20   b , . . . may be an information processor such as a personal computer. 
         [0032]    The server equipment  10  is an information processor. The server equipment  10  is provided with an unillustrated central processing unit (CPU), storage devices (a memory and a hard disk drive (HDD)), and an output device (in the present example, a display). The server equipment  10  is configured such that the CPU executes a program stored in any of the storage devices to thereby realize after-mentioned functions. 
         [0033]    The communication equipment  20   a  is provided with a management communication port  21 , a plurality of communication port units  22   a ,  22   b , . . . , and an unillustrated CPU and a storage device (memory). 
         [0034]    The management communication port  21  is connected with one end of a communication cable MCa. The other end of the communication cable MCa is connected to the server equipment  10 . On the basis of this, the communication equipment  20   a  and the server equipment  10  are communicatively connected to each other. In the present example, the communication equipment  20   a  and the server equipment  10  make communication with each other according to TCP (Transmission Control Protocol) and SSL (Secure Socket Layer). Alternatively, the communication equipment  20   a  and the server equipment  10  may make communication with each other according to another communication protocol. 
         [0035]    The communication port unit  22   a  includes a communication port  22   a   1 , a connection detection unit  22   a   2 , and a light emitting unit  22   a   3 . The light emitting unit  22   a   3  constitutes a part of first notification means. 
         [0036]    The communication port  22   a   1  is detachably connected with a communication cable. The communication equipment  20   a  is configured to be communicable with another communication equipment  20   b , . . . in such a manner that the communication port  22   a   1  is connected with one end of the communication cable and the other end of the communication cable is connected to a communication port of the another communication equipment  20   b, . . . .    
         [0037]    The connection detection unit  22   a   2  detects that the communication port  22   a   1  is connected with the communication cable. In the present example, the connection detection unit  22   a   2  is provided with a pressure sensor that is in abutting contact with the communication cable in a state where the communication port  22   a   1  is connected (attached) with the communication cable. The pressure sensor generates different electrical signals respectively for a state of being in abutting contact with the communication cable and for a state of not being in abutting contact with it. On the basis of this, the connection detection unit  22   a   2  detects that the communication port  22   a   1  is connected with the communication cable. 
         [0038]    Alternatively, the present invention may be configured to, with use of a sensor other than the pressure sensor, detect that the communication port  22   a   1  is connected with the communication cable. For example, the present invention may be configured such that the connection detection unit  22   a   2  is provided with an infrared sensor, and with use of the infrared sensor, detects whether or not the communication cable is present in the communication port  22   a   1  to thereby detect that the communication port  22   a   1  is connected with the communication cable. 
         [0039]    Also, the connection detection unit  22   a   2  may be provided with a spring that is compressed in the state where the communication port  22   a   1  is connected (attached) with the communication cable; also provided with a sensor that detects a compression state of the spring; and thereby detect that the communication port  22   a   1  is connected with the communication cable. 
         [0040]    Further, it is only necessary that the connection detection unit  22   a   2  can detect connection of the communication cable, and convert a result of the detection into a signal to notify a connection notification transmitting unit  31  of the result. For example, the connection detection unit  22   a   2  may use a switch mechanism in place of the pressure sensor to detect the connection and notify of a result of the detection. 
         [0041]    The light emitting unit  22   a   3  is provided with a light emitting diode (LED). In the present example, the light emitting unit  22   a   3  is provided with an LED that emits light having a single color (e.g., blue color). Here, preferably, a color depending on content notified from the server equipment  10  is set. For this purpose, if there are a plurality of content to be notified, different color LEDs respectively depending on the pieces of content are provided for each of the light emitting units. The light emitting unit  22   a   3  is arranged near the communication port  22   a   1 . That is, the light emitting unit  22   a   3  is arranged corresponding to the communication port  22   a   1 . 
         [0042]    In addition, the other communication port units  22   b , . . . also have the same configuration as that of the communication port unit  22   a.    
         [0043]    Further, the communication equipment  20   a  is configured to realize after-mentioned functions in such a manner that the CPU executes a program stored in the storage device. 
         [0044]    Also, the other communication equipments  20   b , . . . have the same configuration as that of the communication equipment  20   a  as well. 
       Functions 
       [0045]      FIG. 2  is a block diagram representing functions of the communication system  1  configured as described above. The functions are realized in such a manner that the CPU of the server equipment  10  executes the program or the like represented by after-mentioned flowcharts illustrated in  FIGS. 7 and 10 , and also the CPU of each of the communication equipments  20   a ,  20   b , . . . executes the program or the like represented by after-mentioned flowcharts illustrated in  FIGS. 6, 8, and 9 . 
         [0046]    Note that the functions of the communication equipment  20   a  are described here; however, the other communication equipments  20   b , . . . also have the same functions as those of the communication equipment  20   a.    
         [0047]    The functions of the communication equipment  20   a  include the connection notification transmitting unit  31 , a communication confirmation information transmitting unit  32 , a light emission control unit (light emission control unit and a part of first notification unit)  33 , a communication confirmation information receiving unit  34 , and a communication confirmation notification transmitting unit  35 . 
         [0048]    Also, the functions of the server equipment  10  include a connection notification receiving unit  41 , a connection configuration information storage unit  42 , a notification instruction transmitting unit  43 , a communication confirmation notification receiving unit  44 , a notification information output unit  45 , and a warning information output unit (first warning information output unit and second warning information output unit)  46 . 
         [0049]    The connection notification transmitting unit  31  transmits connection notification to the server equipment  10  if any of the connection detection units  22   a   2 ,  22   b   2 , . . . detects that a communication cable is connected to a corresponding communication port  22   a   1 ,  22   b   1 , . . . . The connection notification represents that the communication cable is connected to the communication port  22   a   1 ,  22   b   1 , . . . , and includes communication port identification information for identifying the communication port  22   a   1 ,  22   b   1 , . . . connected with the communication cable. 
         [0050]    In the present example, the communication port identification information is information representing an MAC (Media Access Control) address that is preset for the communication port. 
         [0051]    If some of the connection detection units  22   a   2 ,  22   b 2, . . . detect that communication cables are connected to corresponding communication ports  22   a   1 ,  22   b 1, . . . , the communication confirmation information transmitting unit  32  transmits, through the communication ports  22   a   1 ,  22   b   1 , . . . , pieces of communication confirmation information to the communication cables respectively connected to the communication ports  22   a   1 ,  22   b   1 , . . . . If the other ends of the communication cables are connected to other communication equipments, the pieces of communication confirmation information are respectively received by the other communication equipments. The pieces of communication confirmation information include pieces of communication port identification information for identifying the communication ports  22   a   1 ,  22   b , . . . connected with the communication cables, respectively. 
         [0052]    The light emission control unit  33  receives a first notification instruction from the server equipment  10 . The first notification instruction includes communication port identification information for identifying a port that is not connected to a communication cable (hereinafter referred to as unconnected communication port identification information). If receiving the first notification instruction, the light emission control unit  33  makes a light emitting unit (e.g., light emitting unit  22   a   3 ), which is arranged corresponding to the communication port (e.g., communication port  22   a   1 ) indicated by the unconnected communication port identification information included in the first notification instruction, emit blue light. 
         [0053]    If light emission control unit  33  receives the first notification instruction in this manner, the light emitting unit  22   a   3 ,  22   b 3, . . . , and the light emission control unit  33  notify a user of request to connect a communication cable to the communication port  22   a   1 ,  22   b 1, . . . indicated by the unconnected communication port identification information included in the first notification instruction. 
         [0054]    The communication confirmation information receiving unit  34  receives communication confirmation information from another communication equipment  20   b , . . . connected through a communication cable. 
         [0055]    If the communication confirmation information receiving unit  34  receives the communication confirmation information, the communication confirmation notification transmitting unit  35  transmits communication confirmation notification to the server equipment  10 . The communication confirmation notification includes: communication port identification information included in the received communication confirmation information; and communication port identification information for identifying a communication port that the communication equipment  20   a  (device of interest) uses at the time of receiving the communication confirmation information. That is, the communication confirming notification transmitting unit  35  transmits the communication confirming notification to the server equipment  10  with including, in the communication confirming notification, the two pieces of communication port identification information that specify the communication port pair between which communication connection is confirmed and the communication cable is connected. 
         [0056]    The connection configuration information storage unit  42  stores a connection configuration table and a communication equipment identification table.  FIG. 3  is a diagram illustrating an example of the connection configuration table according to the present invention. Referring to  FIG. 3 , the connection configuration table includes at least one piece of connection configuration information. The connection configuration information includes: communication port identification information for identifying each of one set of communication ports (communication port pair) expected to be connected through a communication cable; connection status information that represents whether or not each of the one set of communication ports is connected with the communication cable; and communication confirmation status information that represents whether or not it is confirmed that communication is available between the one set of communication ports. 
         [0057]    In the connection configuration information, two pieces of connection status information respectively corresponding to two pieces of communication port identification information are set. On the basis of a value of connection status information, it can be confirmed whether or not a communication port corresponding to the connection status information and a communication cable are connected to each other. For example, the case where “0” is set in connection status information represents that a corresponding communication port and a communication cable are not connected to each other. On the other hand, the case where “1” is set in the connection status information represents that the corresponding communication port and the communication cable are connected to each other. Also, for one set of (two pieces of) communication port identification information, common communication confirmation status information is set. On the basis of a value of the communication confirmation status information, confirmation status whether or not communication is available between a communication port pair indicated by the one set of communication port identification information can be known. For example, the case where “0” is set in the communication confirmation status information represents that communication is not confirmed between a corresponding communication port pair. On the other hand, the case where “1” is set in the communication confirmation status information represents that communication is confirmed between the corresponding communication pair. 
         [0058]      FIG. 4  is an example of the communication equipment identification table according to the present invention. Referring to  FIG. 4 , the communication equipment identification table includes at least one piece of device port correspondence information. The device port correspondence information includes: communication port identification information; and communication equipment identification information for identifying any of the communication equipments  20   a ,  20   b , . . . , which is provided with a communication port indicated by the communication port identification information. In the present example, the communication equipment identification information is information representing an MAC address that is preset for the communication equipment  20   a ,  20   b , . . . . Alternatively, the communication equipment identification information may be information representing an IP (Internet Protocol) address. 
         [0059]    The connection notification receiving unit  41  receives connection notification from any of the communication equipments  20   a ,  20   b , . . . . The connection notification receiving unit  41  uses, as a search key, communication port identification information included in the received connection notification to search the connection configuration information storage unit  42  (connection configuration table), and updates connection status information corresponding to the communication port identification information to “connected” (e.g., sets the connection status information to “1”). Also, the connection notification receiving unit  41  outputs the received connection notification to the notification instruction transmitting unit  43 , the notification information output unit  45 , and the warning information output unit  46 . 
         [0060]    The communication confirmation notification receiving unit  44  receives communication confirmation notification that is transmitted from any of the communication equipments  20   a ,  20   b , . . . . The communication confirmation notification receiving unit  44  uses one set of (two pieces of) communication port identification information included in the received communication confirmation notification as a search key to search the connection configuration information storage unit  42  (connection configuration table), and updates communication confirmation status information corresponding to the one set of communication port identification information to “communication confirmed” (e.g., sets the communication confirmation status information to “1”). 
         [0061]    The notification instruction transmitting unit  43  uses, as a search key, communication port identification information included in connection notification received in the connection notification receiving unit  41  to search the connection configuration information storage unit  42  (connection configuration table), and specifies connection configuration information including the communication port identification information. 
         [0062]    Referring to connection status information included in connection configuration information that is specified on the basis of connection notification, the notification instruction transmitting unit  43  checks connection status between a communication port pair indicated by the connection configuration information and a communication cable. If there is a communication port that is not connected to the communication cable, the notification instruction transmitting unit  43  uses communication port identification information on the communication port as a search key to search the connection configuration information storage unit  42  (communication equipment identification table), and obtains communication equipment identification information corresponding to the communication port identification information. Then, the notification instruction transmitting unit  43  transmits a first notification instruction including the communication port identification information on the communication port, which is confirmed not to be connected to the communication cable, to a communication equipment indicated by the obtained communication equipment identification information. 
         [0063]    That is, the notification instruction transmitting unit  43  checks, in the connection configuration table, the connection status of the communication port serving as the other side of the communication port connected to the communication cable. At this time, the notification instruction transmitting unit  43  that detects the disconnection notifies the communication equipment having the unconnected communication port of the communication port identification information for identifying the unconnected communication port. 
         [0064]    The notification information output unit  45  uses, as a search key, communication port identification information included in connection notification received in the connection notification receiving unit  41  to search the connection configuration information storage unit  42  (connection configuration table), and specifies connection configuration information including the communication port identification information. 
         [0065]    Referring to connection status information included in the connection configuration information that is specified on the basis of the connection notification, the notification information output unit  45  checks connection status between a communication port pair indicated by the connection configuration information and a communication cable. Also, referring to communication confirmation status information included in the connection configuration information that is specified on the basis of the connection notification, the notification information output unit  45  checks confirmation status on communication connection between the communication port pair indicated by the connection configuration information. If both of the two communication ports included in the connection configuration information are connected to the communication cable, and the communication connection has been confirmed, the notification information output unit  45  outputs in a viewable manner, from the unillustrated output device, notification information indicating that the preset communication pair is communicable through the expected communication cable. 
         [0066]    That is, the notification information output unit  45  checks in the connection configuration table according to the connection notification whether or not the communication port pair preset in the server equipment  10  is communicable. At this time, if between the communication port pair, the communication connection is confirmed, the notification information output unit  45  outputs, in a viewable manner, the notification information indicating the communication port pair between which the communication cable is correctly connected as expected to complete the communication connection. 
         [0067]    In other words, if connection notification including each of one set of communication port identification information included in connection configuration information stored in the connection configuration information storage unit  42  is received, and communication confirmation notification including the one set of communication port identification information included in the connection configuration information is received, the notification information output unit  34  outputs notification information. 
         [0068]    The warning information output unit  46  uses, as a search key, communication port identification information included in connection notification received in the connection notification receiving unit  41  to search the connection configuration information storage unit  42  (connection configuration table), and specifies connection configuration information including the communication port identification information. If communication port identification information that is coincident with the received communication port identification information is not set in the connection configuration information storage unit  42  (connection configuration table), the warning information output unit  46  outputs in a viewable manner, from the unillustrated output device to the server equipment  10 , first warning information indicating that the unset communication port identification information is received. That is, if the connection configuration information including the connection port identification information included in the connection notification is not present in pieces of connection configuration information stored in the connection configuration information storage unit  42 , the warning information output unit  46  outputs the first warning information. In addition, the first warning information is information representing that a communication cable is erroneously connected to any of the communication equipments  20   a ,  20   b, . . . .    
         [0069]    Further, the warning information output unit  46  uses, as a search key, the communication port identification information included in the connection notification received in the connection notification receiving unit  41  to search the connection configuration information storage unit  42  (communication equipment identification table), and obtains communication equipment identification information corresponding to the communication port identification information. 
         [0070]    Referring to pieces of connection status information included in the connection configuration information that is specified on the basis of the connection notification, the warning information output unit  46  checks connection status between a communication port pair indicated by the connection configuration information and a communication cable. Also, referring to communication confirmation status information included in the connection configuration information that is specified on the basis of the connection notification, the warning information output unit  46  checks confirmation status on communication connection between the communication port pair indicated by the connection configuration information. If both of the two communication ports included in the connection configuration information are connected to the communication cable, but the communication connection has not been confirmed, the warning information output unit  46  outputs, in a viewable manner, second warning information indicating such a state from the unillustrated output device. That is, if in the specified connection configuration information, both of the pieces of connection status information respectively corresponding to the one set of communication port identification information represent that the communication cable is connected, and the communication confirmation status information represents that communication is not confirmed, the warning information output unit  46  outputs, in a viewable manner, the second warning information. The second warning information is information representing that a communication cable is erroneously connected to any of the communication equipments  20   a ,  20   b, . . . .    
         [0071]    In other words, if connection notification including each of one set of communication port identification information included in connection configuration information stored in the connection configuration information storage unit  42  is received, but communication confirmation notification including the one set of communication port identification information included in the connection configuration information is not received, the warning information output unit  46  outputs the second warning information in a viewable manner. 
         [0072]    The above-described connection notification receiving unit  41  outputs the received connection notification to the notification instruction transmitting unit  43 , the notification information output unit  45 , and the warning information output unit  46 , and in each of the functional blocks, the connection configuration information and device identification information according to the connection notification are specified; however, the present invention is not limited to this. Each of these functional blocks may confirm connection status between communication ports or whether or not communication between the communication ports is available, with use of connection configuration information that is specified when connection status information is updated by the connection notification receiving unit  41 . 
       Operation 
       [0073]    Next, an operation of the above-described communication system  1  is described referring to  FIGS. 5  to  10 .  FIG. 5  is a sequence diagram representing the operation of the communication system  1 . 
         [0074]    Here, the description is continued on the assumption of the case where the connection configuration information storage unit  42  stores connection configuration information that, as one set of communication port identification information, includes communication port identification information “PID1” for identifying the communication port  22   a   1  of the communication equipment  20   a  and communication port identification information “PID2” for identifying the communication port  22   a   1  of the communication equipment  20   b.    
         [0075]    Referring to  FIG. 5 , described is operation up to request to connect the communication cable to the communication equipment  20   b  that is not connected, in response to connecting a communication cable to the communication port  22   a   1  of the communication equipment  20   a.    
         [0076]    During activation of the communication equipment  20   a , the CPU of the communication equipment  20   a  executes a connection detection processing program illustrated by a flowchart of  FIG. 6 . To describe specifically, when starting to process the connection detection processing program, the communication equipment  20   a  waits in Step S 201  until it detects the connection of the communication cable. 
         [0077]    The communication equipment  20   a  having detected the connection of the communication cable determines a result in Step S 201  as “Yes”, and proceeds to Step S 202  to transmit communication confirmation information (Step S 201 : Yes, S 202 ). For example, the communication equipment  20   a  transmits the communication confirmation information including the communication port identification information “PID1” for identifying the communication port  22   a   1  to the other communication equipment  20   b , . . . through the communication port  22   a   1 . 
         [0078]    Then, the communication equipment  20   a  transmits connection notification to the server equipment  10  (Step S 203 ). Specifically, the communication equipment  20   a  transmits, to the server equipment  10 , the connection notification including the communication port identification information “PID1” on the communication port  20   a   1  connected with the communication cable. Subsequently, the communication equipment  20   a  returns to Step S 201  to wait until the communication cable is connected to the other communication port, and when detecting the connection, performs the processing steps in Steps S 202  and S 203 . 
         [0079]    Referring to  FIG. 5 , when a user (e.g. an administrator of the communication system  1 ) connects one end of the communication cable to the communication port  22   a   1  of the communication equipment  20   a , the connection detection unit  22   a   2  of the communication equipment  20   a  detects that the communication cable is connected to the communication port  22   a   1  (Step S 101 ). On the basis of this, the communication equipment  20   a  transmits the communication confirmation information including the communication port identification information “PID1” to the communication cable through the communication port  22   a   1  (not illustrated). In the present example, the other end of the communication cable connected to the communication port  22   a   1  is not connected to any of the communication equipments  20   b , . . . . Accordingly, the communication equipment  20   a  fails to transmit the communication confirmation information (cannot transmit the communication confirmation information). Then, the communication equipment  20   a  transmits, to the server equipment  10 , the connection notification including the communication port identification information “PID1” on the communication port  20   a   1  connected with the communication cable (Step S 102 ). 
         [0080]    When the connection notification is transmitted from the communication equipment  20   a , the server equipment  10  checks connection status or the like on a communication port serving as a connection target of the communication port that is specified on the basis of the connection notification, and performs a process depending on the connection status (Steps S 102  and S 103 ). In the example illustrated in  FIG. 5 , the server equipment  10  determines that the communication port (communication equipment  20   b ) serving as the connection target is not connected with the communication cable, and transmits a first notification instruction to the communication equipment  20   b  (Step S 103 ). 
         [0081]    Referring to  FIG. 7 , details of a processing step in Step S 103  are described. During activation of the server equipment  10 , the CPU of the server equipment  10  executes a notification instruction transmission processing program illustrated by a flowchart of  FIG. 7 . To describe specifically, when starting to process the notification instruction transmission processing program, the server equipment  10  waits in Step S 301  until it receives the connection notification. 
         [0082]    When receiving the connection notification including the communication port identification information “PID1” from the communication equipment  20   a , the server equipment  10  determines a result in Step S 301  as “Yes”, and proceeds to Step S 302 . 
         [0083]    In Step S 302 , the server equipment  10  determines whether or not connection configuration information including the communication port identification information “PID1” included in the received connection notification is stored (i.e., corresponding connection configuration information is present) in the connection configuration information storage unit  42 . 
         [0084]    According to the above assumption, the connection configuration information including the communication port identification information “PID1” is stored in the connection configuration information storage unit  42 . Accordingly, the server equipment  10  determines a result in Step S 302  as “Yes”, and proceeds to Step S 303  to update the connection configuration table. Specifically, the server equipment  10  sets connection status information related to the communication port identification information “PID1” to “1” in the connection configuration information including the communication port identification information “PID1”. 
         [0085]    Subsequently, the server equipment  10  proceeds to Step S 304  to determine whether or not the communication cable is also connected to the communication port of the other end. Specifically, in the connection configuration information including the communication port identification information “PID1”, the server equipment  10  determined whether or not connection status information related to communication port identification information (i.e., “PID2”) other than the communication port identification information “PID1” represents that the communication cable is connected (i.e., the connection status information is set to “1”). 
         [0086]    At this point, the connection status information related to the communication port identification information “PID2” is set to “0”. Accordingly, the server equipment  10  determines a result in Step S 304  as “No”, and proceeds to Step S 305 . 
         [0087]    Then, the server equipment  10  obtains communication equipment identification information (in this case, “DID2”) included in device port correspondence information including the communication port identification information “PID2” from among pieces of device port correspondence information stored in the connection configuration information storage unit  42 . Subsequently, the server equipment  10  transmits the first notification instruction including the communication port identification information “PID2” to the communication equipment  20   b  that is indicated by the obtained communication equipment identification information “DID2” (Step S 103  in  FIG. 5 ). 
         [0088]    After that, the server equipment  10  returns to Step S 301  to wait until it receives connection notification, and when receiving the connection notification, performs processing steps in Steps S 302  to S 309 . In addition, details of processing steps in Steps S 306  to S 309  will be described later. 
         [0089]    On the other hand, the CPU of the communication equipment  20   b  executes a first notification processing program illustrated by a flowchart of  FIG. 8 . To describe specifically, when starting to process the first notification processing program, the communication equipment  20   b  waits in Step S 401  until it receives the first notification instruction. 
         [0090]    In the present example, the communication equipment  20   b  receives the first notification instruction including the communication port identification information “PID2” from the server equipment  10 . On the basis of this, the communication equipment  20   b  determines a result in Step S 401  as “Yes”, and proceeds to Step S 402 . 
         [0091]    Subsequently, the communication equipment  20   b  makes the light emitting unit  22   a   3 , which is arranged corresponding to the communication port  22   a   1  indicated by the communication port identification information “PID2” included in the first notification instruction, emit blue light (S 402 ). 
         [0092]    After that, the communication equipment  20   b  returns to Step S 401  to wait until it receives a first notification instruction, and when receiving the first notification instruction, performs Step S 402 . 
         [0093]    In the example illustrated in  FIG. 5 , in the communication equipment  20   b  having received the first notification instruction from the server equipment  10 , the light emitting unit  22   a   3  for the communication port  22   a   1  corresponding to the first notification instruction emits light. On the basis of this, the user recognizes that the user should connect the other end of the communication cable connected to the communication port  22   a   1  of the communication equipment  20   a  to the communication port  22   a   1  of the communication equipment  20   b . Then, the user connects the other end of the communication cable to the communication port  22   a   1  of the communication equipment  20   b.    
         [0094]    Meanwhile, as with the communication equipment  20   a , the communication equipment  20   b  executes the connection detection processing program illustrated in  FIG. 6 . Accordingly, the communication equipment  20   b  transmits communication confirmation information including the communication port identification information “PID2” for identifying the communication port  22   a   1  to the communication cable (in this case, the other communication equipment  20   a ) through the communication port  22   a   1  (Step S 202  in  FIG. 6 , and Step S 106  in  FIG. 5 ). On the basis of this, the communication equipment  20   a  receives the communication confirmation information including the communication port identification information “PID2” from the communication equipment  20   b.    
         [0095]    On the other hand, during the activation of the communication equipment  20   a , the CPU of the communication equipment  20   a  executes a communication confirmation notification processing program illustrated by a flowchart of  FIG. 9 . To describe specifically, when starting to process the communication confirmation notification processing program, the communication equipment  20   a  waits in Step S 501  until it receives the communication confirmation information. Then, when receiving the communication confirmation information, the communication equipment  20   a  transmits, to the server equipment  10 , communication confirmation notification including the communication port identification information included in the communication confirmation information and the communication port identification information on the reception port receiving the communication confirmation information (Step S 502 ). Subsequently, the communication equipment  20   a  returns to Step S 501  to wait until it receives communication confirmation information, and when receiving the communication confirmation information, performs the processing step in Step S 502 . 
         [0096]    In the example illustrated in  FIG. 5 , the communication equipment  20   a  receives the communication confirmation information including the communication port identification information “PID2” from the communication equipment  20   b . Accordingly, the communication equipment  20   a  transmits, to the server equipment  10 , the communication confirmation notification including the communication port identification information “PID2” and the communication port identification information “PID1” on the reception port (S 107 ). 
         [0097]    Note that the communication confirmation notification includes: the communication port identification information “PID2” included in the received communication confirmation information; and the communication port identification information “PID1” for identifying the communication port that the communication equipment  20   a  (device of interest) uses at the time of receiving the communication confirmation information. Alternatively, the communication confirmation notification may be performed by notification of a first packet (PacketIN) according to an OpenFlow protocol. For example, the communication confirmation information transmitted from the communication equipment  20   b  does not match a flow entry set for the communication equipment  20   a , and therefore the server equipment  10  (in this case, an open flow controller) is notified of the communication confirmation information as the first packet. By notifying the server equipment  10  of the communication port identification information on the communication port used by the device of interest together with the first packet, the server  10  can confirm the communication port pair between which communication becomes available. 
         [0098]    On the other hand, during the activation of the server equipment  10 , the CPU of the server equipment  10  executes a communication confirmation reception processing program illustrated by a flowchart of  FIG. 10 . To describe specifically, when starting to process the communication confirmation reception processing program, the server equipment  10  waits in Step S 601  until it receives the communication confirmation notification. Then, when receiving the communication confirmation notification, the server equipment  10  updates communication confirmation status information in connection configuration information indicated by the pieces of communication port identification information included in the communication confirmation notification to “communication availability confirmed” (Step S 602 ). Subsequently, the server equipment  10  returns to Step S 601  to wait until it receives communication confirmation notification, and when receiving the communication confirmation notification, performs the processing step in Step S 602 . 
         [0099]    In the example illustrated in  FIG. 5 , the server equipment  10  receives the communication confirmation notification including the communication port identification information “PID1” and the communication port identification information “PID2” from the communication equipment  20   a . Accordingly, the server equipment  10  sets the communication confirmation status information to “1” in the connection configuration information including the communication port identification information “PID1” and the communication port identification information “PID2”. 
         [0100]    Further, the communication equipment  20   b  transmits the connection notification including the communication port identification information “PID2” to the serer device  10  in response to the connection detection in Step S 105  (Step S 203  in  FIG. 6  and Step S 108  in  FIG. 5 ). 
         [0101]    On the basis of the set of connection notification received from the communication equipments  20   a  and  20   b , the server equipment  10  checks the connection of both of the communication port pair expected to be connected, and outputs, in a viewable manner, notification information indicating that the communication port pair has been connected (Step S 109 ). 
         [0102]    In the following, referring to  FIG. 7 , details of the processing step in Step S 109  is described. The server equipment  10  receives the connection notification including the communication port identification information “PID2” from the communication equipment  20   b . On the basis of this, the server equipment  10  determines a result in Step S 301  as “Yes”, and proceeds to Step S 302 . 
         [0103]    The server equipment  10  determines whether or not connection configuration information including the communication port identification information “PID2” included in the received connection notification is stored in the connection configuration information storage unit  42 . 
         [0104]    According to the above assumption, the connection configuration information including the communication port identification information “PID2” is stored in the connection configuration information storage unit  42 . Accordingly, the server equipment  10  determines a result in Step S 302  as “Yes”, and proceeds to Step S 303  to update the connection configuration table. Specifically, in the connection configuration information including the communication port identification information “PID2”, the server equipment  10  sets connection status information related to the communication port identification information “PID2” to “1”. 
         [0105]    Then, the server equipment  10  proceeds to Step S 304  to determine whether or not the communication cable is also connected to the communication port serving as a connection target. Specifically, in the connection configuration information including the communication port identification information “PID2”, the server equipment  10  determines whether or not the connection status information related to the communication port identification information (i.e., “PID1”) other than the communication port identification information “PID2” represents that the communication cable is connected (i.e., the connection status information is set to “1”). 
         [0106]    At this point, the connection status information related to the communication port identification information “PID1” is set to “1”. Accordingly, the server equipment  10  determines a result in Step S 304  as “Yes”, and proceeds to Step S 306 . 
         [0107]    Subsequently, in the connection configuration information including the communication port identification information “PID2” included in the received connection notification, the server equipment  10  determines whether or not communication confirmation status information represents that the communication is confirmed (i.e., the communication confirmation status information is set to “1”). 
         [0108]    At this point, the communication confirmation status information is set to “1”. Accordingly, the server equipment  10  determined a result in Step S 306  as “Yes”, and proceeds to Step S 307  to output, in a viewable manner, the notification information through the output device (not illustrated). 
         [0109]    The notification information is information representing that the communication cable is correctly connected to the communication equipments  20   a ,  20   b , . . . . In the present example, the notification information includes the one set of communication port identification information (i.e., the communication port identification information “PID1” and the communication port identification information “PID2”) on the basis of which the notification information is outputted. 
         [0110]    Subsequently, the server equipment  10  returns to Step S 301  to wait until it receives connection notification, and when receiving the connection notification, performs processing steps in Steps S 302  to S 309 . In addition, details of processing steps in Steps S 308  and  309  will be described later. 
         [0111]    Next, referring to  FIG. 7 , described is operation for the case where one end of a first communication cable is connected to the communication port  22   a   1  of the communication equipment  20   a , and then one end of a second communication cable different from the first communication cable is erroneously connected to the communication port  22   a   1  of the communication equipment  20   b.    
         [0112]    In this case, at the point when the one end of the second communication cable is erroneously connected to the communication port  22   a   1  of the communication equipment  20   b , the communication equipment  20   a  cannot receive communication confirmation information from the communication equipment  20   b . Accordingly, the communication equipment  20   a  does not transmit communication confirmation notification to the server equipment  10 . 
         [0113]    From the communication equipments  20   a  and  20   b , one set of connection notification, which represents that the communication cables are respectively connected to the corresponding communication ports  22   a   1 , is received, and therefore in the connection configuration information including the communication port identification information “PID1” and the communication port identification information “PID2”, the pieces of connection status information respectively corresponding to the communication equipments  20   a  and  20   b  are set to “1”. On the other hand, the communication confirmation status information included in the connection configuration information including the communication port identification information “PID1” and the communication port identification information “PID2” is still set to “0”. Accordingly, the server equipment  10  proceeds to a processing step in Step S 306  to determine a result of the processing step as “No”. As a result, the server equipment  10  outputs, in a viewable manner, the second warning information through the unillustrated output device (Step S 308 ). 
         [0114]    The second warning information is information representing that the communication cables are erroneously connected to the communication equipments  20   a ,  20   b , . . . . In the present example, the second warning information includes the one set of communication port identification information (i.e., the communication port identification information “PID1” and the communication port identification information “PID2”) on the basis of which the second warning information is outputted. 
         [0115]    Subsequently, the server equipment  10  returns to Step S 301  to wait until it receives connection notification, and when receiving the connection notification, repeatedly performs the processing steps in Step S 302  to S 309 . 
         [0116]    Next, referring to  FIG. 7 , described is operation for the case where under the condition that communication port identification information “PID3” for identifying the communication port  22   b   1  of the communication equipment  20   a  is not included in any of the pieces of connection configuration information stored in the connection configuration information storage unit  42  (i.e., the communication port  22   b   1  is not expected to be connected with a communication cable), a communication cable is erroneously connected to the communication port  22   b   1 . 
         [0117]    In this case, the server equipment  10  determines a result of the processing step in Step S 302  of  FIG. 7  as “No”, and outputs, in a viewable manner, the first warning information through the unillustrated output device. 
         [0118]    The first warning information is information representing that a communication cable is erroneously connected to any of the communication equipment  20   a ,  20   b , . . . . Specifically, the first warning information includes information indicating that a communication cable is connected to a communication port that is not expected to be connected. In the present example, the first warning information includes the communication port identification information on the basis of which the first warning information is outputted (i.e., the communication port identification information “PID3”). 
         [0119]    Subsequently, the server equipment  10  returns to step S 301  to wait until it receives connection notification, and when receiving the connection notification, performs the processing steps in Steps S 302  to S 309 . 
         [0120]    As described above, according to the communication system according to the first exemplary embodiment of the present invention, when a user connects one end of a communication cable to a communication port  22   a   1 , the communication equipment  20   a  provided with the communication port  22   a   1  transmits connection notification to the server equipment  10 . The server equipment  10  updates connection status of the communication port indicated by the connection notification to “connected”, and uses the connection configuration information table to check status of connecting a communication port, which is expected as a connection target, to the communication cable. At this time, if the communication port serving as a communication target is not connected to the communication cable, the server equipment  10  transmits a first notification instruction including communication port identification information on the communication port to the communication equipment  20   b  provided with the communication port. 
         [0121]    Then, the communication equipment  20   b  having received the first notification instruction notifies the user of request to connect the communication cable to the communication port  22   a   1  indicated by the communication port identification information included in the first notification instruction. In this case, an LED that specifies the communication port necessary to be connected lights. As a result, the user can easily identify the connection target of the other end of the communication cable of which the one end is connected to the communication port. In the present example, when connecting the one end of the communication cable to the communication port  22   a   1  of the communication equipment  20   a , the user can easily identify the communication port  22   a   1  of the communication equipment  20   b , which is to be connected with the other end of the communication cable. 
         [0122]    Further, in the communication system  1  according to the first exemplary embodiment, in the case where the server equipment  10  receives connection notification from any of the communication equipments  20   a ,  20   b , . . . , if among the pieces of stored connection configuration information, connection configuration information including communication port identification information included in the connection notification is not present, the server equipment  10  outputs the first warning information representing that the communication equipment is erroneously connected with a communication cable. 
         [0123]    That is, the server equipment  10  outputs, in a viewable manner, the first warning information if a communication cable is connected to a communication port that is not expected to be connected with any communication cable. On the basis of this, a user can easily recognize that the communication cable is erroneously connected to the communication equipment  20   a ,  20   b, . . . .    
         [0124]    Still further, in the communication system  1  according to the first exemplary embodiment, in the case where connection notification, which includes each of one set of communication port identification information included in stored connection configuration information, is received, but communication confirmation notification including the one set of communication port identification information included in the pieces of connection configuration information is not received, the server equipment  10  outputs the second warning information representing that a communication cable is erroneously connected to any of the communication equipments  20   a ,  20   b, . . . .    
         [0125]    That is, the server equipment  10  outputs, in a viewable manner, the second warning information if mutually different communication cables are respectively connected to one set of communication ports that are supposed to be connected by the same communication cable. On the basis of this, a user can easily recognize that one of the communication cables is erroneously connected to any of the communication equipments  20   a ,  20   b, . . . .    
         [0126]    Yet further, in the communication system  1  according to the first exemplary embodiment, in the case where connection notification, which includes each of one set of communication port identification information included in stored connection configuration information, is received, and communication confirmation notification including the one set of communication port identification information included in the connection configuration information is received, the server equipment  10  outputs notification information representing that a communication cable is correctly connected to any two of the communication equipments  20   a ,  20   b, . . . .    
         [0127]    That is, the server equipment  10  outputs, in a viewable manner, the notification information in the case where the communication cable is connected to each of one set of communication ports as expected. On the basis of this, a user can easily recognize that the communication cable is correctly connected to the two communication equipments  20   a ,  20   b, . . . .    
         [0128]    Note that the server equipment  10  according to the first exemplary embodiment preliminarily stores the pieces of connection configuration information; however, the present invention may be configured to generate pieces of connection configuration information on the basis of pieces of information representing the communication equipments  20   a ,  20   b , . . . constituting the communication system  1  and pieces of information representing a preset connecting plan, and store the pieces of generated connection configuration information in any of the storage devices. 
       Second Exemplary Embodiment 
       [0129]    Next, a communication system according to a second exemplary embodiment of the present invention is described. The communication system according to the second exemplary embodiment is different from the communication system according to the above first exemplary embodiment in detecting that a communication state between communication ports is an abnormal state. Accordingly, in the following, the description is provided with a focus on such a point of difference. 
         [0130]    Each of light emitting units  22   a   3 ,  22   b   3 , . . . according to the second exemplary embodiment is provided with: a first LED that emits, for example, blue light; and a second LED that emits light having a different color from that of the first LED (e.g., red). 
         [0131]    As illustrated in  FIG. 11 , functions of a communication equipment  20   a  according to the second exemplary embodiment include, in addition to the functions of the communication equipment  20   a  according to the first exemplary embodiment, a data amount transmitting unit  36 . 
         [0132]    Also, functions of a server equipment  10  according to the second exemplary embodiment include, in addition to the functions of the server equipment  10  according to the first exemplary embodiment, a failure detection unit  47 . 
         [0133]    The data amount transmitting unit  36  transmits data amount information to the server equipment  10  every time a preset transmission period passes. The data amount information is information including communication port identification information, transmitted data amount, and received data amount regarding each of communication ports  22   a   1 ,  22   b 1, . . . provided for the communication equipment  20   a.    
         [0134]    The transmitted data amount is an amount of data that has been transmitted through the communication port during passage of the transmission period. The received data amount is an amount of data that has been received through the communication port during passage of the transmission period. 
         [0135]    The failure detection unit  47  receives data amount information from each of the communication equipments  20   a ,  20   b , . . . . Every time a preset detection period passes, the failure detection unit  47  extracts, from among pieces of connection configuration information stored in the connection configuration information storage unit  42 , pieces of connection configuration information each in which communication confirmation status information is set to “1”. 
         [0136]    The failure detection unit  47  detects whether or not a communication state between communication ports indicated by one set of communication port identification information included in each of the pieces of extracted connection configuration information is the abnormal state. 
         [0137]    Specifically, the failure detection unit  47  specifies pieces of data amount information respectively corresponding to the one set of communication port identification information included in the connection configuration information. The failure detection unit  47  calculates a value (first value) obtained by, from transmitted data amount included in one (first data amount information) of the one set of specified data amount information, subtracting received data amount included in the other one (second data amount information) of the one set of specified data amount information. Further, the failure detection unit  47  calculates a value (second value) obtained by, from transmitted data amount included in the second data amount information, subtracting received data amount included in the first data amount information. 
         [0138]    If at least one of the first and second values is larger than a preset threshold value, the failure detection unit  47  detects that the communication state between the communication ports indicated by the one set of communication port identification information is the abnormal state. 
         [0139]    In this manner, the failure detection unit  47  receives a transmitted data amount and a received data amount for each of the communication ports, and on the basis of the received transmitted data amount and received data amount, detects that a communication state between communication ports is the abnormal state. 
         [0140]    If the failure detection unit  47  detects that a communication state between communication ports is the abnormal state, the notification instruction transmitting unit  43  transmits a second notification instruction to each of communication equipments  20   a ,  20   b , . . . provided with the communication ports. The second notification instruction includes a corresponding one of pieces of communication port identification information for identifying the communication ports. 
         [0141]    The light emission control unit  33  receives the second notification instruction from the server equipment  10 . The second notification instruction includes a corresponding one of the pieces of communication port identification information. When receiving the second notification instruction, the light emission control unit  33  makes any of light emitting units  22   a   3 ,  22   b   3 , . . . , which is arranged corresponding to a communication port  22   a   1 ,  22   b   1 , . . . indicated by the communication port identification information included in the second notification instruction, emit red light (i.e., makes the second LED emit light). 
         [0142]    In this manner, when the light emission control unit  33  receives the second notification instruction, the light emitting unit  22   a   3 ,  22   b   3 , . . . and the light emission control unit  33  notify a user that a state of the communication port  22   a   1 ,  22   b   1 , . . . indicated by the communication port identification information included in the second notification instruction is the abnormal state. That is, any of the light emitting units  22   a   3 ,  22   b   3 , . . . and the light emission control unit  33  constitute a second notification unit. 
         [0143]    Next, operation of the communication system  1  according to the second exemplary embodiment is described referring to  FIG. 12 . 
         [0144]    First, each of the communication equipments  20   a  and  20   b  transmits data amount information to the server equipment  10  every time the transmission period passes (Steps S 701  and S 702 ) 
         [0145]    In the following, the description is continued on the assumption of the case where a communication state between the communication port  22   a   1  of the communication equipment  20   a  and the communication port  22   a   1  of the communication equipment  20   b  is the abnormal state. 
         [0146]    In this case, on the basis of pieces of connection configuration information stored in the connection configuration information storage unit  42  and the pieces of received data amount information, the server equipment  10  detects that the communication state between the communication port  22   a   1  of the communication equipment  20   a  and the communication port  22   a   1  of the communication equipment  20   b  is the abnormal state (Step S 703 ). 
         [0147]    Then, the server equipment  10  transmits the second notification instruction including the communication port identification information “PID1” for identifying the communication port  22   a   1  of the communication equipment  20   a  to the communication equipment  20   a . Further, the server equipment  10  transmits the second notification instruction including the communication port identification information “PID2” for identifying the communication port  22   a   1  of the communication equipment  20   b  to the communication equipment  20   b.    
         [0148]    In the communication equipment  20   a , the light emitting unit  22   a   3  that is arranged corresponding to the communication port  22   a   1  indicated by the communication port identification information “PID1” received from the server equipment  10  emits red light (Step S 705 ). 
         [0149]    Similarly, in the communication equipment  20   b , the light emitting unit  22   a   3  that is arranged corresponding to the communication port  22   a   1  indicated by the communication port identification information “PID2” received from the server equipment  10  emits red light (Step S 706 ). 
         [0150]    As described above, according to the communication system according to the second exemplary embodiment of the present invention, the same action and effect as those of the communication system  1  according to the first exemplary embodiment can be produced. 
         [0151]    Further, according to the communication system  1  according to the second exemplary embodiment, the server equipment  10  can detect that a communication state between communication ports is the abnormal state. 
         [0152]    In addition, if it is detected that a communication state between communication ports is the abnormal state, the communication system  1  according to the second exemplary embodiment notifies a user of the detection. According to this, the user can easily recognize that the state between the communication ports is the abnormal state. Further, the user can also easily identify the communication ports in the abnormal state. 
         [0153]    Note that each of the communication equipments  20   a ,  20   b , . . . according to the second exemplary embodiment is configured to, when receiving the first notification instruction, make a corresponding light emitting unit  22   a   3 ,  22   b 3, . . . emit blue light, and on the other hand, when receiving the second notification instruction, make the corresponding light emitting unit  22   a   3 ,  22   b 3, . . . emit red light. That is, any of the light emitting units  22   a   3 ,  22   b 3, . . . according to the second exemplary embodiment emits light having a different color depending on each of the first and second notification instructions. This enables a user to identify content of a notification instruction with a color of the light emitting unit  22   a   3 ,  22   b   3 , . . . . 
         [0154]    However, a method for identifying content of a notification instruction is not limited to this, but may be one that, depending on content of a notification instruction, changes a light emitting mode of a corresponding light emitting unit  22   a   3 ,  22   b   3 , . . . . For example, each of the communication equipments  20   a ,  20   b , . . . according to the variation of the second exemplary embodiment may be configured to, when receiving the first notification instruction, make a corresponding light emitting unit  22   a   3 ,  22   b 3, . . . emit light in a first mode, and on the other hand, when receiving the second notification instruction, emit the light emitting unit  22   a   3 ,  22   b   3 , . . . emit light in a second mode. Specifically, the first mode is a mode that blinks the light emitting unit  22   a   3 ,  22   b   3 , . . . , and the second mode is a mode that keeps the light emitting unit  22   a   3 ,  22   b   3 , . . . emitting light. 
       Third Exemplary Embodiment 
       [0155]    Next, a communication system according to a third exemplary embodiment of the present invention is described referring to  FIG. 13 . 
         [0156]    The communication system  100  according to the third exemplary embodiment is a system provided with: a plurality of communication equipments  110   a ,  110   b , . . . that are configured to be mutually connectable through a communication cable; and a server equipment  120  that are communicatively connected to each of the plurality of communication equipments  110   a ,  110   b, . . . .    
         [0157]    Each of the plurality of communication equipments  110   a ,  110   b , . . . is provided with at least one communication port  111  that is detachably connected with a communication cable. Also, each of the plurality of communication equipments  110   a ,  110   b , . . . is provided with a connection detection unit  112  and a connection notification transmitting unit  113 . The connection detection unit  112  detects that the communication cable is connected to the communication port  111 . In the case where it is detected that the communication cable is connected to the above communication port, the connection notification transmitting unit  113  transmits, to the above server equipment  120 , connection notification including communication port identification information for representing the detection and identifying the communication port. 
         [0158]    Further, the server equipment  120  is provided with a connection configuration information storage unit  121  and a first notification instruction transmitting unit  122 . The connection configuration information storage unit  121  stores at least one piece of connection configuration information including one set of connection port identification information respectively for identifying one set of communication ports connected through a communication cable. When receiving the above connection notification from any of the communication equipments  110   a ,  110   b , . . . , the first notification instruction transmitting unit  122  transmits, to another communication equipment  110   a ,  110   b , . . . provided with a communication port indicated by communication port identification information included in connection configuration information that is from among the pieces of connection configuration information stored in the connection configuration information storage unit  121  and includes other communication port identification information included in the connection notification, first notification instruction including the communication port identification information. 
         [0159]    In addition, each of the plurality of communication equipments  110   a ,  110   b , . . . is provided with a first notification unit  114  that, when the communication equipment  110   a ,  110   b , . . . receives the first notification instruction from the server equipment  120 , notifies a user of request to connect a communication cable to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0160]    According to this, when a user connects one end of a communication cable to a communication port  111 , any of the communication equipments  110   a ,  110   b , . . . , which is provided with the communication port  111 , transmits connection notification to the server equipment  120 . This causes the server equipment  120  to, on the basis of the pieces of stored connection configuration information and communication port identification information included in the received connection notification, transmit a first notification instruction to another communication equipment  110   a ,  110   b , . . . provided with another communication port  111  to be connected with the other end of the above communication cable. 
         [0161]    The another communication equipment  110   a ,  110   b , . . . having received the first notification instruction notifies the user of request to connect the communication cable to the another communication port  111  indicated by communication port identification information included in the first notification instruction. As a result, when connecting the one end of the communication cable to the communication port  111 , the user can easily identify the another communication port  111  to be connected with the other end of the communication cable. 
       Fourth Exemplary Embodiment 
       [0162]    Next, a communication system according to a fourth exemplary embodiment of the present invention is described referring to  FIGS. 2, and 14 to 17 . The communication system according to the fourth exemplary embodiment is different from that of the first exemplary embodiment in that communication confirmation information between communication equipments is transmitted in response to a communication confirmation request from a server equipment  10 , and the rest of a configuration and operation are the same as those of the first exemplary embodiment. In the following, a configuration and operation that are different from those of the first exemplary embodiment are described. 
       Configuration 
       [0163]    In response to communication confirmation request from the server equipment  10 , the communication confirmation information transmitting unit  32  according to the fourth exemplary embodiment transmits communication confirmation information to a communication cable connected to a communication port indicated by the communication confirmation request. 
         [0164]    The communication confirmation notification receiving unit  44  according to the fourth exemplary embodiment uses, as a search key, one set (two pieces) of communication port identification information included in received communication confirmation notification to search the connection configuration information storage unit  42  (connection configuration table), and updates communication confirmation status information corresponding to the one set of communication port identification information to “communication confirmed” (e.g., sets the communication confirmation status information to “1”). Also, the communication confirmation notification receiving unit  44  outputs the received communication confirmation notification to the notification information output unit  45 . 
         [0165]    The notification information output unit  45  confirms, on the basis of the communication confirmation notification, that communication becomes available between a communication port pair preset in the server equipment  10 . When confirming communication connection between the communication port pair, the notification information output unit  45  outputs, in a viewable manner, notification information indicating the communication port pair between which a communication cable is correctly connected as expected to complete the communication connection. Note that the communication confirmation notification is transmitted only from one of communication equipments of which the communication port pair is correctly connected with the communication cable, and therefore on the basis of the communication confirmation notification, the notification information output unit  45  can confirm that the communication cable is correctly connected, and between the communication port pair, the communication becomes available. 
       Operation 
       [0166]    Next, the operation of the communication system in the fourth exemplary embodiment is described. In the following, the same operation as that in the first exemplary embodiment is described with being added with the same symbols as those in the first exemplary embodiment, and details of different operation are described. 
         [0167]    Referring to  FIG. 14 , described is operation up to, in response to connection of a communication cable to the communication port  22   a   1  of the communication equipment  20   a , urging to connect the communication cable to the communication equipment  20   b  that is not connected. 
         [0168]    During activation of the communication equipment  20   a , the CPU of the communication equipment  20   a  executes a connection detection processing program illustrated by a flowchart of  FIG. 15 . To describe specifically, when starting to process the connection detection processing program, the communication equipment  20   a  waits in Step S 201  until it detects the connection of the communication cable. 
         [0169]    The communication equipment  20   a  having detected the connection of the communication cable determines a result in Step S 201  as “Yes”, and proceeds to Step S 203  to transmit connection notification to the server equipment  10  (Step S 203 ). Specifically, the communication equipment  20   a  transmits, to the server equipment  10 , the connection notification including communication port identification information “PID1” on the communication port  20   a   1  connected with the communication cable. Subsequently, the communication equipment  20   a  returns to Step S 201  to wait until a communication cable is connected to another communication port, and when detecting the connection, performs the processing step in Step S 203 . 
         [0170]    Referring to  FIG. 14 , when a user (e.g., an administrator of the communication system  1 ) connects one end of the communication cable to the communication port  22   a   1  of the communication equipment  20   a , the connection detection unit  22   a   2  of the communication device  20   a  detects that the communication cable is connected to the communication port  22   a   1  (Step S 101 ). On the basis of this, the communication equipment  20   a  transmits, to the server equipment  10 , the connection notification including the communication port identification information “PID1” on the communication port  20   a   1  connected with the communication cable (Step S 102 ). 
         [0171]    When the connection notification is transmitted from the communication equipment  20   a , as in the first exemplary embodiment, the server equipment  10  transmits a first notification instruction to the communication equipment  20   b  (Step S 103 ). 
         [0172]    In an example illustrated in  FIG. 14 , in the communication equipment  20   b  having received the first notification instruction from the server equipment  10 , as in the first exemplary embodiment, the light emitting unit  22   a   3  for the communication port  22   a   1  corresponding to the first notification instruction emits light. On the basis of this, the user recognizes that the user should connect the other end of the communication cable connected to the communication port  22   a   1  of the communication equipment  20   a  to the communication port  22   a   1  of the communication equipment  20   b . Then, the user connects the other end of the communication cable to the communication port  22   a   1  of the communication equipment  20   b.    
         [0173]    As with the communication equipment  20   a , the communication equipment  20   b  executes the connection detection processing program illustrated in  FIG. 15 . Accordingly the communication equipment  20   b  having detected the connection of the communication cable to the communication port  22   a   1  transmits connection notification including communication port identification information “PID2” to the server equipment  10 . 
         [0174]    On the basis of the set of connection notification received from the communication equipments  20   a  and  20   b , the server equipment  10  according to the fourth exemplary embodiment confirms the connection of both of the communication port pair expected to be connected. At this time, whether or not communication is available between the communication port pair is not confirmed, and therefore the server equipment  10  outputs, in a viewable manner, second warning information and transmits a communication confirmation request to the communication equipment  20   b  (Steps S 112  and S 113 ). The communication confirmation request includes the pieces of communication port identification information for identifying the communication port pair. 
         [0175]    In response to the communication confirmation request, the communication equipment  20   b  transmits communication confirmation information including the communication port identification information “PID2” for identifying the communication port  22   a   1  to the communication cable (here, the other communication equipment  20   a ) through the communication port  22   a   1  (Step S 106 ). This causes the communication equipment  20   a  to receive the communication confirmation information including the communication port identification information “PID2” from the communication equipment  20   b.    
         [0176]    As in the first exemplary embodiment, the communication equipment  20   a  transmits communication confirmation notification to the server equipment  10  (Step S 107 ). 
         [0177]    On the other hand, during activation of the server equipment  10 , the CPU of the server equipment  10  according to the fourth exemplary embodiment executes a communication confirmation reception processing program illustrated by a flowchart of  FIG. 17 . As in the first exemplary embodiment, the server equipment  10  waits in Step S 601  until it receives the communication confirmation notification, and when receiving the communication confirmation notification, updates communication confirmation status information in connection configuration information indicated by the pieces of communication port identification information included in the communication confirmation notification to “communication availability confirmed” (Step S 602 ). Subsequently, the server equipment  10  outputs, in a viewable manner, notification information indicating that the connection between the communication port pair is completed (Step S 603  and Step S 114  in  FIG. 14 ). At this time, it is preferable to stop the output of the second warning information. 
         [0178]    As described above, in the communication system in the fourth exemplary embodiment, the server equipment  10  having confirmed the connection from the communication equipments  20   a  and  20   b  controls communication confirmation operation between the communication equipments. This enables unnecessary communication availability/unavailability confirmation operation by the communication equipment  20   a  having detected the connection of the communication cable to be omitted. 
         [0179]    In the above, the present invention has been described referring to the above exemplary embodiments; however, the present invention is not limited to any of the above-described exemplary embodiments. Various modifications that one having ordinary skill in the art can appreciate can be made to constitution and detail of the present invention within the scope of the present invention. 
         [0180]    Note that each of the functions of the communication system  1  in any of the above exemplary embodiments is realized by the CPUs executing the programs (software): however they may be realized by hardware such as a circuit. 
         [0181]    Also, in each of the above exemplary embodiments, the programs are stored in the storage devices; however, they may be stored in a computer-readable recording medium. For example, the recording medium is a portable medium such as a flexible disk, an optical disk, a magneto-optical disk, or a semiconductor memory. 
         [0182]    Further, as another variation of the above exemplary embodiments, any combination of the above-described exemplary embodiments and variation may be employed. For example, the first warning information or second warning information may be outputted to any of the communication equipments  20   a  and  20   b  each of which is a transmission source of connection notification. In this case, each of the communication equipments  20   a  and  20   b  is preferably provided with an output device that outputs, in a viewable manner, the first or second warning information. Alternatively, the light emitting unit  22   a   3  may emit light in a mode that identifies the first or second warning information (identifies it by a light emission color, blinking interval, or the like). 
         [0183]    &lt;Supplementary Notes&gt; 
         [0184]    Part or all of the above-described exemplary embodiments can be described as in the following Supplementary notes, but not limited to the following. 
         [0185]    (Supplementary Note 1) 
         [0186]    A communication system comprising: a plurality of communication equipments that are configured to be mutually connectable through a communication cable; and a server equipment that is communicatively connected to each of the plurality of communication equipments, wherein: 
         [0187]    each of the plurality of communication equipments comprises 
         [0188]    at least one communication port that is detachably connected with the communication cable, and also comprises 
         [0189]    a connection detection unit that detects that the communication cable is connected to the communication port, and 
         [0190]    a connection notification transmitting unit that, if it is detected that the communication cable is connected to the communication port, transmits, to the server equipment, connection notification including communication port identification information for representing the detection and identifying the communication port; 
         [0191]    the server equipment comprises 
         [0192]    a connection configuration information storage unit that stores at least one piece of connection configuration information including pieces of communication port identification information for respectively identifying one set of communication ports connected through the communication cable, and 
         [0193]    a first notification instruction transmitting unit that, if the connection notification is received from the communication equipment, transmits, to a communication equipment provided with a communication port indicated by communication port identification information included in connection configuration information including other communication port identification information included in the connection notification, a first notification instruction including the communication port identification information, the connection configuration information being from among the stored connection configuration information; and 
         [0194]    each of the plurality of communication equipments further comprises 
         [0195]    a first notification unit that, if the first notification instruction is received from the server equipment, notifies a user of request to connect the communication cable to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0196]    According to this, when the user connects one end of a communication cable to a communication port, a communication equipment provided with the communication port transmits connection notification to the server equipment. This causes the server equipment to, on the basis of the stored connection configuration information and communication port identification information included in the received connection notification, transmit first notification instruction to a communication equipment provided with a communication port to be connected with the other end of the communication cable. 
         [0197]    Then, the communication equipment having received the first notification instruction notified the user of request to connect the communication cable to the communication port indicated by communication port identification information included in the first notification instruction. As a result, when connecting the one end of the communication port to the communication port, the user can easily specifies the communication port to be connected with the other end of the communication cable. 
         [0198]    (Supplementary Note 2) 
         [0199]    The communication system according to Supplementary note 1, wherein 
         [0200]    the server equipment comprises 
         [0201]    a first warning information output unit that, when the connection notification is received from the communication equipment, if among the stored connection configuration information, the connection configuration information including the communication port identification information included in the connection notification is not present, outputs first warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0202]    According to this, the server equipment outputs the first warning information if a communication port not expected to be connected with any communication cable is connected with a communication cable. This enables the user to easily recognize that the communication cable is erroneously connected to a communication equipment. 
         [0203]    (Supplementary Note 3) 
         [0204]    The communication system according to Supplementary note 1 or 2, wherein: 
         [0205]    each of the plurality of communication equipments comprises 
         [0206]    a communication confirmation information transmitting unit that transmits, to the other communication equipment connected through the communication cable, communication confirmation information including the communication port identification information for identifying the communication port connected with the communication cable, 
         [0207]    a communication confirmation information receiving unit that receives the communication confirmation information from the other communication equipment connected through the communication equipment, and 
         [0208]    a communication confirmation notification transmitting unit that, when the communication confirmation information is received, transmits, to the server equipment, communication confirmation notification including the communication port identification information included in the communication confirmation information and the communication port identification information for identifying the communication port that when receiving the communication confirmation information, the device of interest uses; and 
         [0209]    the server equipment comprises 
         [0210]    a second warning information output unit that, if the connection notification including each of the set of communication port identification information included in the stored connection configuration information is received, but the communication confirmation notification including the one set of communication port identification information included in the connection configuration information is not received, outputs second warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0211]    According to this, the server equipment outputs the second warning information if one set of communication ports that are expected to be connected by the same communication cable are respectively connected with mutually different communication cables. This enables the user to easily recognize that a communication cable is erroneously connected to a communication equipment. 
         [0212]    (Supplementary Note 4) 
         [0213]    The communication system according to Supplementary note 3, wherein 
         [0214]    the server equipment comprises 
         [0215]    a notification information output unit that, if the connection notification including each of the one set of communication port identification information included in the stored connection configuration information is received, and the connection confirmation notification including the one set of communication port identification information included in the connection configuration information is received, outputs notification information representing that the communication cable is correctly connected to the communication equipments. 
         [0216]    According to this, the server equipment outputs notification information when a communication cable is connected to each of one set of communication ports as expected. This enables the user to easily recognize that the communication cable is correctly connected to communication equipments. 
         [0217]    (Supplementary Note 5) 
         [0218]    The communication system according to any one of Supplementary notes 1 to 4, wherein: 
         [0219]    each of the plurality of communication equipments comprises 
         [0220]    a data amount transmitting unit that, for each of the communication ports provided for the communication equipment, transmits, to the server equipment, a transmitted data amount that is an amount of data transmitted through the communication port, and also transmits, to the server equipment, a received data amount that is an amount of data received through the communication port; and 
         [0221]    the server equipment comprises 
         [0222]    an failure detection unit that, for each of the communication ports, receives the transmitted data amount and the received data amount, and on a basis of the received transmission data amount and the received data amount, detects that a communication state between the communication ports is an abnormal state. 
         [0223]    According to this, the server equipment can detect that the communication state between the communication ports is the abnormal state. 
         [0224]    (Supplementary Note 6) 
         [0225]    The communication system according to Supplementary note 5, wherein: 
         [0226]    the server equipment comprises 
         [0227]    a second notification instruction transmitting unit that, if it is detected that the communication state between the communication ports is the abnormal state, transmits, to the communication equipments provided with the communication ports, a second notification instruction including the pieces of communication port identification information for identifying the communication ports, respectively; and 
         [0228]    each of the plurality of communication equipments further comprises 
         [0229]    a second notification unit that, if the second notification instruction is received from the server equipment, notifies the user that a state between the communication ports indicated by the pieces of communication port identification information included in the second notification instruction is the abnormal state. 
         [0230]    According to this, the user can easily recognize that the state between the communication ports is the abnormal state. Further, the user can also easily identify the communication ports in the abnormal state. 
         [0231]    (Supplementary Note 7) 
         [0232]    The communication system according to any one of Supplementary notes 1 to 6, wherein 
         [0233]    the first notification unit 
         [0234]    includes a plurality of light emitting units that emit light, wherein the plurality of light emitting units are arranged with being respectively related to the communication ports provided for the device of interest, and 
         [0235]    includes a light emission control unit that, if the first notification instruction is received, makes a light emitting unit among the plurality of light emitting units emit light, the light emitting unit being arranged corresponding to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0236]    (Supplementary Note 8) 
         [0237]    A communication method that is applied to a communication system comprising: a plurality of communication equipments that are configured to be mutually connectable through a communication cable; and a server equipment that is communicatively connected to each of the plurality of communication equipments, wherein: 
         [0238]    each of the plurality of communication equipments comprises at least one communication port that is detachably connected with the communication cable; 
         [0239]    the communication equipment detects that the communication cable is connected to the communication port; 
         [0240]    if detecting that the communication cable is connected to the communication port, the communication equipment transmits, to the server equipment, connection notification including communication port identification information for representing the detection and identifying the communication port; 
         [0241]    if receiving the connection notification from the communication equipment, the server equipment transmits, to a communication equipment provided with a communication port indicated by communication port identification information included in connection configuration information including other communication port identification information included in the connection notification, a first notification instruction including the communication port identification information, the connection configuration information being from among pieces of connection configuration information stored in a storage device that stores at least the one piece of connection configuration information including the pieces of communication port identification information for respectively identifying the one set of communication ports connected through the communication cable; and 
         [0242]    if receiving the first notification instruction from the server equipment, the communication equipment notifies a user of request to connect the communication cable to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0243]    (Supplementary Note 9) 
         [0244]    The communication method according to Supplementary note 8, wherein 
         [0245]    when receiving the connection notification from the communication equipment, if among the pieces of stored connection configuration information, the connection configuration information including the communication port identification information included in the connection notification is not present, the server equipment outputs first warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0246]    (Supplementary Note 10) 
         [0247]    The communication method according to Supplementary note 8 or 9, wherein; 
         [0248]    the communication equipment transmits, to the other communication equipment connected through the communication cable, communication confirmation information including the communication port identification information for identifying the communication port connected with the communication cable; 
         [0249]    the communication equipment receives the communication confirmation information from the other communication equipment connected through the communication equipment; 
         [0250]    if receiving the communication confirmation information, the communication equipment transmits, to the server equipment, communication confirmation notification including the communication port identification information included in the communication confirmation information and the communication port identification information for identifying the communication port that when receiving the communication confirmation information, the device of interest uses; and 
         [0251]    if receiving the connection notification including each of the one set of communication port identification information included in the stored connection configuration information, but not receiving the communication confirmation notification including the one set of communication port identification information included in the connection configuration information, the server equipment outputs second warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0252]    (Supplementary Note 11) 
         [0253]    A server equipment that is communicatively connected to each of a plurality of communication equipments configured to be mutually connectable through a communication cable, the server equipment comprising: 
         [0254]    a connection configuration information storage unit that stores at least one piece of connection configuration information including pieces of communication port identification information for respectively identifying one set of communication ports connected through the communication cable, and 
         [0255]    a first notification instruction transmitting unit that, if connection notification including communication port identification information for identifying a communication port provided for a communication equipment is received from the communication equipment, transmits, to a communication equipment provided with a communication port indicated by other communication port identification information included in connection configuration information including the communication port identification information included in the connection notification, a first notification instruction including the communication port identification information, the connection configuration information being from among the stored connection configuration information. 
         [0256]    (Supplementary Note 12) 
         [0257]    The server equipment according to Supplementary note 11, comprising 
         [0258]    a first warning information output unit that, when the connection notification is received from the communication equipment, if among the stored connection configuration information, the connection configuration information including the communication port identification information included in the connection notification is not present, outputs first warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0259]    (Supplementary Note 13) 
         [0260]    The server equipment according to Supplementary note 11 or 12, comprising 
         [0261]    a second warning information output unit that, if the connection notification including each of the one set of communication port identification information included in the stored connection configuration information is received, but communication confirmation notification including the one set of communication port identification information included in the connection configuration information is not received, outputs second warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0262]    (Supplementary Note 14) 
         [0263]    A program intended to instruct a server equipment to realize, the server equipment being communicatively connected to each of a plurality of communication equipment configured to be mutually connectable through a communication cable, 
         [0264]    a connection configuration information storage unit that stores at least one piece of connection configuration information including pieces of communication port identification information for respectively identifying one set of communication ports connected through the communication cable, and 
         [0265]    a first notification instruction transmitting unit that, if connection notification including communication port identification information for identifying a communication port provided for a communication equipment is received from the communication equipment, transmits, to a communication equipment provided with a communication port indicated by other communication port identification information included in connection configuration information including the communication port identification information included in the connection notification, a first notification instruction including the communication port identification information, the connection configuration information being from among the stored connection configuration information. 
         [0266]    (Supplementary Note 15) 
         [0267]    The program according to Supplementary note 14, the program being intended to further instruct the server equipment to realize 
         [0268]    a first warning information output unit that, when the connection notification is received from the communication equipment, if among the stored connection configuration information, the connection configuration information including the communication port identification information included in the connection notification is not present, outputs first warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0269]    (Supplementary Note 16) 
         [0270]    The program according to Supplementary note 14 or 15, the program being intended to further instruct the server equipment to realize 
         [0271]    a second warning information output unit that, if the connection notification including each of the one set of communication port identification information included in the stored connection configuration information is received, but communication confirmation notification including the one set of communication port identification information included in the connection configuration information is not received, outputs second warning information representing that the communication cable is erroneously connected to the communication equipment. 
         [0272]    (Supplementary Note 17) 
         [0273]    A communication equipment that is communicatively connected to a server equipment and configured to be connectable to another device through a communication cable, the communication equipment comprising 
         [0274]    at least one communication port that is detachably connected with the communication cable, and also comprising: 
         [0275]    a connection detection unit that detects that the communication cable is connected to the communication port; 
         [0276]    a connection notification transmitting unit that, if it is detected that the communication cable is connected to the communication port, transmits, to the server equipment, connection notification including communication port identification information for representing the detection and identifying the communication port; and 
         [0277]    a first notification unit that, if first notification instruction including communication port identification information for identifying a communication port is received from the server equipment, notifies a user of request to connect the communication cable to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0278]    (Supplementary Note 18) 
         [0279]    The communication equipment according to Supplementary note 17, comprising: 
         [0280]    a communication confirmation information transmitting unit that transmits, to the another communication equipment connected through the communication cable, communication confirmation information including the communication port identification information for identifying the communication port connected with the communication cable; 
         [0281]    a communication confirmation information receiving unit that receives the communication confirmation information from the another communication equipment connected through the communication equipment; and 
         [0282]    a communication confirmation notification transmitting unit that, when the communication confirmation information is received, transmits, to the server equipment, communication confirmation notification including the communication port identification information included in the communication confirmation information and the communication port identification information for identifying the communication port that when receiving the communication confirmation information, the device of interest uses. 
         [0283]    (Supplementary Note 19) 
         [0284]    A program intended to instruct a communication equipment to realize, the communication equipment being communicatively connected to a server equipment, also configured to be connectable to another device through a communication cable, and comprising at least one communication port that is detachably connected with the communication cable, 
         [0285]    a connection detection unit that detects that the communication cable is connected to the communication port; 
         [0286]    a connection notification transmitting unit that, if it is detected that the communication cable is connected to the communication port, transmits, to the server equipment, connection notification including communication port identification information for representing the detection and identifying the communication port; and 
         [0287]    a first notification unit that, if first notification instruction including communication port identification information for identifying the communication port is received from the server equipment, notifies a user of request to connect the communication cable to the communication port indicated by the communication port identification information included in the first notification instruction. 
         [0288]    (Supplementary Note 20) 
         [0289]    The program according to Supplementary note 19, the program being intended to further instruct the communication equipment to realize 
         [0290]    a communication confirmation information transmitting unit that transmits, to the another communication equipment connected through the communication cable, communication confirmation information including the communication port identification information for identifying the communication port connected with the communication cable, 
         [0291]    a communication confirmation information receiving unit that receives the communication confirmation information from the another communication equipment connected through the communication equipment, and 
         [0292]    a communication confirmation notification transmitting unit that, when the communication confirmation information is received, transmits, to the server equipment, communication confirmation notification including the communication port identification information included in the communication confirmation information and the communication port identification information for identifying the communication port that when receiving the communication confirmation information, the device of interest uses. 
         [0293]    The present invention may be applied to a communication system in which a server equipment controls a communication route including a plurality of communication equipments (for example, a system using the OpenFlow). It should be noted that this application is based upon Japanese Patent Application JP-2010-035684 and the disclosure of Japanese Patent Application JP-2010-035684 is incorporated herein in its entirety by reference.