Abstract:
A communication device includes a request receiving module and a response output module. The request receiving module receives a communication start request which is output from a given communication device and passes through a relay device. The response output module outputs a response to the communication start request to the given communication device through the relay device. The relay device outputs the response to the given communication device in preference to a notification indicating a connection rejection in arbitration processing, executed by the relay device, between information to be output from the relay device in case where the request receiving module receives the communication start request while communicating with a communication device other than the given communication device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims priority under 35 USC 119 from Japanese Patent Application No. 2010-189713, filed Aug. 26, 2010. 
     BACKGROUND 
     1. Technical Field 
     This invention relates to a communication device, a communication system, and a computer readable medium. 
     2. Related Art 
     An IP facsimile machine for conducting digital communications of image information using an Internet protocol exists. Some IP facsimile machines can conduct not only digital communications of image information using the Internet protocol, but also analog communications of image information via a public telephone switch line. Such an IP facsimile machine includes not only a communication interface compatible with the Internet protocol such as a LAN card, but also a communication interface compatible with the public telephone switch line such as analog facsimile communication card. 
     In recent years, communications have been conducted between facsimile machines using a next generation network (NGN) of a base network for providing new information communication service in which fixed communications and mobile communications are merged and telephone, data communications, and streaming broadcast are merged. A repeater such as a home gateway device may be used as a device for relaying communications between the next generation network and the IP facsimile machine. 
     When a repeater such as a home gateway device relays communications between the next generation network and the IP facsimile machine, generally an optical fiber connected to the next generation network is connected to the corresponding port of the repeater. A LAN cable connected to a LAN card included by the IP facsimile machine and a modular cable connected to an analog facsimile communication card included by the IP facsimile machine are connected to the corresponding ports of the repeater. When analog communications are conducted between the IP facsimile machines, analog-digital conversion and digital-analog conversion are performed in the repeater. 
     When a communication start request according to the Internet protocol (for example, INVITE request in SIP (Session Initiation Protocol)) is transmitted from an IP facsimile machine to an associated IP facsimile machine via the next generation network, one repeater places the start request in all ports of the repeater as an incoming call and transmits a response determined by executing arbitration processing among responses when the responses from all ports are complete (for example, response determined based on predetermined priority) to the IP facsimile machine transmitting the start request. 
     When the communication start request is transmitted to the associated IP facsimile machine while the associated IP facsimile machine is communicating with another facsimile machine, arbitration processing is performed between a response indicating communicating from the LAN port of the repeater (for example, 486 response in SIP) and a response indicating communication rejection from the analog port of the repeater (for example, 488 response in SIP), whereby the response indicating communication rejection (for example, 488 response in SIP) may be transmitted to the IP facsimile machine transmitting the start request. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, a communication device includes a request receiving module and a response output module. The request receiving module receives a communication start request which is output from a given communication device and passes through a relay device. The response output module outputs a response to the communication star request to the given communication device through the relay device. The relay device outputs the response to the given communication device in preference to a notification indicating a connection rejection in arbitration processing, executed by the relay device, between information to be output from the relay device in case where the request receiving module receives the communication start request while communicating with a communication device other than the given communication device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a drawing to show an example of the general configuration of an exemplary embodiment of the invention; 
         FIG. 2  is a function block diagram to show an example of the function realized by a communication system according to the exemplary embodiment of the invention; 
         FIG. 3  is a flowchart to show an example of a flow of processing performed by the communication system according to the exemplary embodiment of the invention; and 
         FIG. 4  is a flowchart to show an example of a flow of processing performed by the communication system according to the exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the invention will be discussed below in detail based on the accompanying drawings: 
       FIG. 1  is a drawing to show an example of the general configuration of an exemplary embodiment of the invention. As illustrated in  FIG. 1 , a first communication system  10 - 1 , a second communication system  10 - 2 , and a third communication system  10 - 3  are connected to communication means (in the exemplary embodiment, for example, next generation network (NGN)  12 ) and communicate with each other. The first communication system  10 - 1  includes a first communication device  14 - 1  and a first repeater  16 - 1 ; the second communication system  10 - 2  includes a second communication device  14 - 2  and a second repeater  16 - 2 ; and a third communication system  10 - 3  includes a third communication device  14 - 3  and a third repeater  16 - 3 . 
     The communication device  14  is, for example, an IP facsimile machine and is made up of a control section of a program control device of a CPU, etc., operating in accordance with a program installed in the communication device  14 , a storage section of storage elements of ROM, RAM, etc., a hard disk drive, etc., a read section for reading an image formed on a surface of a sheet, a print section for printing a sheet on which an image received from another communication device  14 , a digital communication section of a communication interface for digital communications such as a LAN card, and an analog communication section of a communication interface for analog communications such as an analog facsimile communication card. The components are connected through a bus. 
     The repeater  16  is, for example, a home gateway device for repeating communications between the communication devices  14  through the NGN  12  and is made up of a control section of a program control device of a CPU, etc., operating in accordance with a program installed in the communication device  14 , a storage section of storage elements of ROM, RAM, etc., a hard disk drive, etc., a first port of a communication port used for digital communications with the communication device  14 , a second port of a communication port used for analog communications with the communication device  14 , and a third port of a communication port used for digital communications with the NGN  12 . 
     The first port of the repeater  16  and the digital communication section of the communication device  14  are connected by a digital communication cable (in the exemplary embodiment, for example, a LAN cable  18 ). The second port of the repeater  16  and the analog communication section of the communication device  14  are connected by an analog communication cable (in the exemplary embodiment, for example, a modular cable  20 ). The third port of the repeater  16  and the NGN  12  are connected by an optical fiber  22  in the exemplary embodiment, for example. 
       FIG. 2  is a function block diagram to show an example of the function realized by the communication system  10  according to the exemplary embodiment of the invention. As illustrated in  FIG. 2 , the communication device  14  includes a communication start request output section  30 , a communication start request acceptance section  32 , a response notification output section  34 , a response notification acceptance section  36 , an image information output section  38 , an image information acceptance section  40 , a disconnection request output section  42 , and a disconnection request acceptance section  44 . The repeater  16  includes a request repeating section  50 , a response notification repeating section  52 , an arbitration processing execution section  54 , and an image information repeating section  56 . 
     The components are realized as control sections of the communication device  14  and the repeater  16  of computer executed programs installed in the communication device  14  and the repeater  16 . The programs are supplied to the communication device  14  and the repeater  16 , for example, through a computer-readable information storage medium of a CD-ROM, a DVD-ROM, etc., or through communication means of the Internet, etc. 
     An example of a flow of processing performed in the communication system  10  according to the exemplary embodiment will be discussed with reference to a flowchart of  FIG. 3 . In the processing example, an example of a processing flow when the first communication device  14 - 1  transmits a communication start request to the second communication device  14 - 2  when the second communication device  14 - 2  is not communicating with the third communication device  14 - 3 . 
     First, the communication start request output section  30  of the first communication device  14 - 1  outputs a communication start request (in the processing example, INVITE request in SIP (Session Initiation Protocol)) for requesting the second communication device  14 - 2  to start IP facsimile communications (for example, communications based on T.38 protocol) (S 101 ). The request repeating section  50  of the first repeater  16 - 1  relays the communication start request so that the communication start request arrives at the second repeater  16 - 2  via the NGN  12  (S 102 ). 
     When the request repeating section  50  of the second repeater  16 - 2  accepts the communication start request, the request repeating section  50  places the communication start request in the first port and the second port of the second repeater  16 - 2  as an incoming call (S 103 ). Since the first port of the second repeater  16 - 2  is a communication port used for digital communications, the request repeating section  50  of the second repeater  16 - 2  relays the communication start request from the first port to the second communication device  14 - 2  (S 104 ). On the other hand, since the second port of the second repeater  16 - 2  is a communication port used for analog communications, the second port of the second repeater  16 - 2  outputs a response notification indicating connection rejection (in the processing example, a notification that the value of response code in SIP is 488 (Not Acceptable Here)) to the response notification repeating section  52  of the second repeater  16 - 2  without outputting the communication start request to the second communication device  14 - 2 . 
     When the communication start request acceptance section of the second communication device  14 - 2  accepts the communication start request output from the first port of the second repeater  16 - 2 , the response notification output section  34  of the second communication device  14 - 2  outputs a response notification indicating that communication with the first communication device  14 - 1  are acceptable (for example, notification of definite response that the value of response code in SIP is 200 (OK)) to the first communication device  14 - 1 . The response notification repeating section  52  of the second repeater  16 - 2  accepts the response notification through the first port (S 105 ). 
     The arbitration processing execution section  54  of the second repeater  16 - 2  executes arbitration processing between the response notification indicating that communications are acceptable, accepted by the response notification repeating section  52  from the first port and the response notification indicating connection rejection accepted by the response notification repeating section  52  from the second port (S 106 ). In the exemplary embodiment, the arbitration processing execution section  54  determines that the response notification indicating that communications are acceptable has higher priority than the response notification indicating connection rejection, and commands the response notification repeating section  52  of the second repeater  16 - 2  to output the response notification indicating that communications are acceptable to the first communication device  14 - 1 . 
     The response notification repeating section  52  of the second repeater  16 - 2  outputs the response notification indicating that communications are acceptable destined for the first communication device  14 - 1  to the first repeater  16 - 1  via the NGN  12  (S 107 ). The response notification repeating section  52  of the first repeater  16 - 1  relays the response notification to the first communication device  14 - 1 . The response notification acceptance section  36  of the first communication device  14 - 1  accepts the response notification through the first port of the first communication device  14 - 1  (S 108 ). 
     Then, the image information output section  38  of the first communication device  14 - 1  outputs image information to be output to the second communication device  14 - 2  via the image information repeating section  56  of the first repeater  16 - 1  and the image information repeating section  56  of the second repeater  16 - 2 . The image information acceptance section  40  of the second communication device  14 - 2  accepts the image information. The image information is thus transmitted from the first communication device  14 - 1  to the second communication device  14 - 2 . 
     The disconnection request output section  42  of the first communication device  14 - 1  outputs a disconnection request to the second communication device  14 - 2  via the request repeating section  50  of the first repeater  16 - 1  and the request repeating section  50  of the second repeater  16 - 2 . The disconnection request acceptance section  44  of the second communication device  14 - 2  accepts the disconnection request. The response notification output section  34  of the second communication device  14 - 2  outputs a line disconnection notification to the first communication device  14 - 1  via the response notification repeating section  52  of the second repeater  16 - 2  and the response notification repeating section of the first repeater  16 - 1 . The response notification acceptance section  36  of the first communication device  14 - 1  accepts the notification. The communications between the first communication device  14 - 1  and the second communication device  14 - 2  are thus disconnected. 
     Another example of a flow of processing performed in the communication system  10  according to the exemplary embodiment will be discussed with reference to a flowchart of  FIG. 4 . In the processing example, an example of a processing flow when the first communication device  14 - 1  transmits a communication start request to the second communication device  14 - 2  when the second communication device  14 - 2  and the third communication device  14 - 3  are communicating with each other. 
     First, the communication start request output section  30  of the first communication device  14 - 1  outputs a communication start request to the second communication device  14 - 2  as in the processing at  5101  described above (S 201 ). The request repeating section  50  of the first repeater  16 - 1  relays the communication start request as in the processing at S 102  described above (S 202 ). 
     The request repeating section  50  of the second repeater  16 - 2  places the communication start request in the first port and the second port of the second repeater  16 - 2  as an incoming call, as in the processing at S 103  described above (S 203 ). The request repeating section  50  of the second repeater  16 - 2  relays the communication start request from the first port to the second communication device  14 - 2  as in the processing at S 104  described above (S 204 ). On the other hand, the second port of the second repeater  16 - 2  outputs a response notification indicating connection rejection to the response notification repeating section  52  of the second repeater  16 - 2  without outputting the communication start request to the second communication device  14 - 2 . 
     When the communication start request acceptance section of the second communication device  14 - 2  accepts the communication start request output from the first port of the second repeater  16 - 2 , the response notification output section  34  of the second communication device  14 - 2  outputs a response notification indicating the second communication device  14 - 2  is being called (in the processing example, notification of temporary response that the value of response code in SIP is 180 (Ringing)) rather than a response notification indicating the second communication device  14 - 2  is communicating to the first communication device  14 - 1  based on the fact that the second communication device  14 - 2  is communicating with the third communication device  14 - 3 . The response notification repeating section  52  of the second repeater  16 - 2  accepts the response notification through the first port (S 205 ). 
     The arbitration processing execution section  54  of the second repeater  16 - 2  executes arbitration processing between the response notification indicating that calling accepted by the response notification repeating section  52  from the first port and the response notification indicating connection rejection accepted by the response notification repeating section  52  from the second port (S 206 ). In the exemplary embodiment, the arbitration processing execution section  54  determines that the response notification indicating calling has higher priority than the response notification indicating connection rejection, and commands the response notification repeating section  52  of the second repeater  16 - 2  to output the response notification indicating calling to the first communication device  14 - 1 . 
     The response notification indicating calling arrives at the first communication device  14 - 1  (S 208 ) via the first repeater  16 - 1  (S 207 ) as in the processing at  5107  described above. 
     Thus, in the processing example, the first communication device  14 - 1  accepts the response notification indicating the second communication device  14 - 2  is being called. 
     Then, if communications of the second communication device  14 - 2  with the third communication device  14 - 3  terminate within a predetermined time (for example, 10 seconds) since the second communication device  14 - 2  output the response notification indicating the second communication device  14 - 2  is being called, the second communication device  14 - 2  outputs a response notification indicating that communications with the first communication device are acceptable (for example, notification of definite response that the value of response code in SIP is 200 (OK)) to the first communication device  14 - 1 . This notification arrives at the first communication device  14 - 1  via the second repeater  16 - 2 , the NGN  12 , and the first repeater  16 - 1 . Then, image information is transmitted from the first communication device  14 - 1  to the second communication device  14 - 2  according to processing similar to that described above and communications between the first communication device  14 - 1  and the second communication device  14 - 2  are disconnected. 
     On the other hand, if communications of the second communication device  14 - 2  with the third communication device  14 - 3  do not terminate when a predetermined time (for example, 10 seconds) has elapsed since the second communication device  14 - 2  output the response notification indicating the second communication device  14 - 2  is being called, the response notification output section  34  of the second communication device  14 - 2  outputs a response notification indicating the second communication device  14 - 2  is communicating (in the processing example, notification that the value of response code in SIP is 486 (Busy Here)) to the first communication device  14 - 1 . This notification arrives at the first communication device  14 - 1  according to processing similar to that described above. 
     The invention is not limited to the exemplary embodiment. 
     For example, in the processing at  5205  described above, the response notification output section  34  of the second communication device  14 - 2  may output notification of temporary response (notification that the value of response code in SIP is the hundreds) other than the response notification indicating calling to the first communication device  14 - 1  based on the fact that communications with the third communication device  14 - 3  are being conducted. 
     The exemplary embodiment may be applied to a scene where information is transferred between the communication devices according to any other protocol than SIP (for example, H.323, MGCP, etc.). The exemplary embodiment may be applied to communications between the communication systems  10  connected to communication means different from the NGN  12  (for example, a LAN, the internet, etc.). The exemplary embodiment may be applied to any other device than the facsimile machine (for example, a telephone, a stream distribution device, etc.). 
     The specific numeric values and the character strings described above are for illustrative purposes only and the invention is not limited to the numeric values or the character strings. 
     The foregoing description of the exemplary embodiment of the present invention has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and various will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling other skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 
     DESCRIPTION OF REFERENCE NUMERALS 
       10  Communication system,  12  Next generation network (NGN),  14  Communication device,  16  Repeater,  18  LAN cable,  20  Modular cable,  22  Optical fiber,  30  Communication start request output section,  32  Communication start request acceptance section,  34  Response notification output section,  36  Response notification acceptance section,  38  Image information output section,  40  Image information acceptance section,  42  Disconnection request output section,  44  Disconnection request acceptance section,  50  Request repeating section,  52  Response notification repeating section,  54  Arbitration processing execution section,  56  Image information repeating section