Abstract:
An apparatus for providing device information on devices arranged on a network includes a registering unit, a discovering unit, a database, and a providing unit. The registering unit is configured to register device information on a first device that does not support an automatic discovery scheme with which a device on the network is automatically discovered. The discovering unit is configured to discover a second device that supports the automatic discovery scheme and to obtain device information on the second device. The database is configured to store the device information. The providing unit is configured to provide the device information on the first device to the second device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-170167, filed on Jun. 9, 2005, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a method and apparatus for providing device information with which information on devices arranged on an in-home network is obtained to be provided to each of the devices.  
         [0004]     2. Description of the Related Art  
         [0005]     Recently, along with networking of devices, such as a personal computer (PC), an audiovisual (AV) equipment and white goods, an in-home network in an ordinary household has been being developed. To use a service provided through a network with the devices in such in-home network, it is necessary to obtain information on a service provider such as an internet protocol (IP) address. Conventionally, information on the devices to be connected has been obtained by a user.  
         [0006]      FIG. 15  is a schematic for illustrating a structure in which device information is automatically obtained. There is a method of obtaining information on devices A to D arranged on an in-home network  110 , as shown in  FIG. 15 , based on a universal-plug-and-play (UPnP) automatic-device-discovery protocol (UPnP device architecture). The devices A and B that are provided with the UPnP automatic-device-discovery protocol can detect each other by automatically exchanging an automatic-discovery protocol message.  
         [0007]     When various kinds of automatic-discovery protocols are used, a protocol gateway (GW)  1510  is provided so that information on devices having different protocols can be automatically obtained (For example, Japanese Patent Publication No. 2003-501765). Different automatic-discovery protocols are mutually converted by the protocol gateway  1510 . Thus, device information of the devices A and B provided with the automatic-discovery protocols, such as a UPnP device or an HAVi device, can be automatically obtained.  
         [0008]     However, in reality, very few devices are provided with such automatic-discovery protocols and most of home appliances are not provided with the automatic-discovery protocols. Therefore, the devices A and B cannot obtain information of the devices C and D, which are ones of most of devices that are not provided with the automatic-discovery protocols in a house. Moreover, the devices C and D cannot obtain information on any other device including the devices A to D because no function of obtaining the information is provided.  
         [0009]     As another method to obtain the device information, the device information on the devices A to D are manually input and made accessible on a web based server. However, if there is a change in a condition of the devices A to D, wrong information is provided until the device information is updated by manual correction.  
         [0010]     AS described above, in the conventional technologies, it is difficult for the devices A to D on the in-home network  110  to obtain information of all of the devices A to D including the latest device information.  
       SUMMARY OF THE INVENTION  
       [0011]     It is an object of the present invention to at least solve the problems in the conventional technology.  
         [0012]     An apparatus according to one aspect of the present invention is for providing device information on devices arranged on a network and includes a registering unit configured to register device information on a first device that does not support an automatic discovery scheme with which a device on the network is automatically discovered; a discovering unit configured to discover a second device that supports the automatic discovery scheme, and to obtain device information on the second device; and a providing unit configured to provide the device information on the first device, to the second device.  
         [0013]     A method according to another aspect of the present invention is for providing device information on devices arranged on a network and includes registering device information on a first device that does not support an automatic discovery scheme with which a device on the network is automatically discovered; discovering a second device that supports the automatic discovery scheme; obtaining device information on the second device; and providing the device information on the first device, to the second device.  
         [0014]     The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a schematic of an apparatus for providing device information according to a first embodiment of the present invention;  
         [0016]      FIG. 2  is a table of device information stored in a device information database;  
         [0017]      FIG. 3  is a sequence diagram of an operation to record and provide the device information according to the first embodiment;  
         [0018]      FIG. 4  is a schematic for illustrating the device information;  
         [0019]      FIG. 5  is a schematic of an apparatus for providing device information according to a second embodiment of the present invention;  
         [0020]      FIG. 6  is a sequence diagram of an operation to record and provide the device information according to the second embodiment;  
         [0021]      FIG. 7  is a table of device information stored in the device information database;  
         [0022]      FIG. 8  is a sequence diagram of an operation to record and provide the device information according to a third embodiment of the present invention;  
         [0023]      FIG. 9  is a flowchart of an address monitoring process according to a fourth embodiment of the present invention;  
         [0024]      FIG. 10  is a sequence diagram of an operation to update the device information according to the fourth embodiment;  
         [0025]      FIG. 11  is a schematic for illustrating update of information in the device information database;  
         [0026]      FIG. 12  is a schematic of an apparatus for providing device information according to a fifth embodiment of the present invention;  
         [0027]      FIG. 13  is a sequence diagram of an operation to record and provide the device information according to the fifth embodiment;  
         [0028]      FIG. 14  is a schematic of an apparatus for providing device information according to a sixth embodiment of the present invention; and  
         [0029]      FIG. 15  is a schematic for illustrating a structure in which the device information is automatically obtained. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]     Exemplary embodiments according to the present invention are explained in detail below with reference to the accompanying drawings.  
         [0031]      FIG. 1  is a schematic of an apparatus for providing device information according to a first embodiment of the present invention. On the in-home network  110 , devices A and B that are compatible with an automatic discovery protocol, for example, the UPnP protocol, and devices C and D that are incompatible with the automatic discovery protocol are arranged. Besides, an apparatus for providing device information  100  is separately arranged on the in-home network  110 . A setup terminal  120  that inputs device information into the apparatus  100  is connected to the apparatus  100 .  
         [0032]     The apparatus  100  provides device information to each of the devices A, B, C, and D on the in-home network  110 . A setup user interface (setup UI)  101  is an interface to manually set and record, from the setup terminal  120 , device information of the devices C and D. An automatic discovery processor  102  automatically obtains device information of the devices A and B based on the automatic discovery protocol and provides the device information.  
         [0033]     A device information database (device information DB)  103  collectively manages the device information recorded via the setup UI  101  and the device information obtained by the automatic discovery processor  102 . The device information on each of the devices A, B, C, and D is stored in the device information DB  103 . A monitoring unit  104  periodically monitors correctness of the device the information stored in the device information DB  103 . When a change is found in the device information, the monitoring unit  104  updates the device information in the device information DB  103  to the latest information.  
         [0034]     An information providing interface (I/F)  105  is an interface through which the device information in the device information DB  103  is referred from an external devices, for example, the devices A, B, C, D, and provided to the external devices.  
         [0035]     The apparatus  100  collectively controls the device information of all the devices A, B, C, and D on the in-home network  110 . To provide the device information to the devices A and B, the automatic discovery processor  102  advertises the device information of the devices C and D to the in-home network  110  based on the UPnP protocol. Thus, the devices A and B obtain the device information of the devices C and D.  
         [0036]     On the other hand, to provide the device information to the devices C and D, it is configured such that the devices C and D can access the device information DB  103  via the information providing I/F  105 . For example, if a web server interface is used as the information providing I/F  105 , the devices C and D can obtain the device information of all the devices A to D managed in the apparatus  100  by accessing a uniform resource locater (URL) of the information providing I/F  105  from a browser of the devices C and D. A method of providing the device information to the devices C and D is not limited to a method using the web server, and if the devices C and D has a specific information obtaining function, the apparatus  100  can also provide the device information in a format suitable for specifications of such a function.  
         [0037]     Thus, the apparatus  100  provides the device information of all the devices A to D, to both the devices A and B, which are automatic discovery protocol compatible, and the devices C and D, which are automatic discovery protocol incompatible. Moreover, the monitoring unit  104  monitors the correctness of the device information in the device information DB  103  and obtains the latest device information. Thus, the device information DB  103  always stores the latest device information, thereby providing the latest device information to the devices A to D on the in-home network  110  without manual operation.  
         [0038]      FIG. 2  is a table of the device information stored in the device information DB  103 . Device information  200  for includes a device name (name), a network address (IP address, medium access control (MAC) address), a device type (device type), a control URL (action URL), a control/function entry (actions), remarks (for example, name of a manufacturer and a model number). The device information  200 , which is input via the setup UI  101 , is stored in the device information DB  103 .  
         [0039]     The automatic discovery processor  102  discovers the device B based on the automatic discovery protocol, obtains the device information and service information of the device B discovered, and records the device information and the service information in the device information DB  103 . The device information includes items shown in  FIG. 2 . Thus, the apparatus  100  collectively controls and grasps the devices A and B, which are UPnP compatible and the devices C and D, which are UPnP incompatible, on the in-home network  110 .  
         [0040]     To explain an operation to provide the device information, the device B is taken as an example of an automatic-discovery-protocol (UPnP) compatible device, and the device C is taken as an example of an automatic-discovery-protocol (UPnP) incompatible device, for the conveniences sake.  
         [0041]      FIG. 3  is a sequence diagram of the operation to record and provide the device information according to the first embodiment. A user of the in-home network  110  accesses the apparatus  100  from the setup terminal  120 , and inputs a setting D 1  of the device information of the device C via the setup UI  101 . For example, if a web server interface is used as the setup UI  101 , the device information is input through a web browser of the setup terminal  120 .  
         [0042]     When new device information or an update of the device information is registered from the setup terminal  120 , the apparatus  100  provides a device information advertisement D 2  (UPnP discovery) in the form of a multicast packet to the device B to notify the device C statically registered as a virtual UPnP-compatible device.  
         [0043]     The device B accesses a site based on URL information included in the device information advertisement D 2  and issues a device information request D 3  (HTTP GET) to obtain device information D 4  (UPnP device description) of the device C. The device B can also access a site based on a service information URL (SCPDURL) included in-the device information D 4  and issue a service information request D 5  to obtain service information D 6  (detailed information of service and function: UPnP service Description) of the device C. The device information D 4  and the service information D 6  of the device C are generated by the apparatus  100  based on the information that is statically registered via the setup UI  101  (see  FIG. 1 ).  
         [0044]      FIG. 4  is a schematic for illustrating the device information (device description). The device information is structured as shown in the device information D 4 . In the device information D 4 , the device type of the device C is informed as a security adapter, which does not exist in UPnP regulations. In the UPnP regulations, regulation of an original device type is permitted. A device code of a standard device is urn: schemas-upnp-org:device: . . . . Other items in the device information are set to the information that is input via the setup UI  101 .  
         [0045]     The apparatus  100  also periodically performs a discovery process D 10  on the device B on the in-home network  110 . The periodic device discovery process D 10  is achieved by periodically issuing a UPnP-device discovery message D 11  (M-Search). Upon receiving the UPnP-device discovery message D 11 , the device B outputs a device-discovery response message D 12  (M-Search response) that includes the URL information of the device B based on the UPnP protocol.  
         [0046]     The apparatus  100  accesses the URL included in the device-discovery response message D 12  and issues a device information request D 13  to obtain device information D 14  of the device B. The apparatus  100  accesses the service information URL included in the device information D 14 , and issues a service information request D 15  to obtain service information D 16 . Next, the apparatus  100  adds new device information or updates the device information.  
         [0047]     When the device B is shut down, a device shutdown information message D 20  (UPnP byebye) is output from the device B. The device shutdown information message D 20  acts as a trigger and causes the apparatus  100  to delete an entry of the device B from the device information DB  103 .  
         [0048]     The device C performs a device information reference D 31  (HTTP-GET) with respect to the apparatus  100  to obtain device information  32  of each of the devices B and C on the in-home network  110 .  
         [0049]     Thus, according to the first embodiment, it is possible to provide the device information of both the devices A and B that are automatic discovery protocol compatible and the devices C and D that are automatic discovery protocol incompatible on the in-home network  110 .  
         [0050]     In the first embodiment, even when the device information changes, a change is not reflected in the device information to be provided to the devices A to D. The apparatus  100  according to a second embodiment of the present invention periodically monitors the device information in the device information DB  103  and updates the database information if required. Furthermore, based on results of updating, the apparatus  100  provides updated device information to the devices A to D.  
         [0051]      FIG. 5  is a schematic of an apparatus for providing device information according to the second embodiment. As shown in  FIG. 5 , the device information of the devices C and D is stored in the device information DB  103 , and the UPnP incompatible device D is shut down.  
         [0052]     The monitoring unit  104  periodically confirms existence of each of the devices A to D that are controlled by the device information DB  103 . An operation to confirm the existence of the devices A to D by a common internet-control message protocol (ICMP) is explained next.  
         [0053]      FIG. 6  is a sequence diagram of the operation to record and provide the device information according to the second embodiment. The apparatus  100  periodically sends an iCMP (echo request) message D 40  to the devices C and D that are registered in the device information DB  103 . For example, upon receiving the ICMP message D 40 , the device C that exists on the in-home network  110  responds with an ICMP (echo reply) message D 41  based on the ICMP. The device D, which is shut down, does not respond with the ICMP (echo reply) message D 41 .  
         [0054]     The apparatus  100  thus determines that the device D is shut down. The apparatus  100  deletes an entry of the device D to update the device information DB  103 . Because the entry of the device D is deleted, the apparatus  100  generates a device information advertisement (UPnP byebye) message D 42  and provides the device information announcement message D 42  to the in-home network  110 . Thus, the device B can recognize that the device D is shut down. Moreover, when the device C accesses the device information DB  103  via the information providing I/F  105  and performs a device information reference (HTTP-GET) D 43 , since device information D 44  does not include the device information of the device D, the shutdown condition of the device D can be recognized.  
         [0055]     According to the second embodiment, the apparatus  100  confirms the existence of the devices that registered in the device information DB  103 , and if the existence of a device cannot be confirmed, deletes the device information of the device from the device information DB  103 . Thus, unnecessary device information is not provided to other devices, and the devices A to D can receive device information of only the devices A to D that are currently usable.  
         [0056]     In the second embodiment, when the D is shut down, the entry of the device information of the device D is deleted. Due to this, when the UPnP incompatible device D is turned on to be alive again, the device information of the device D needs to be input again via the setup UI  101 . In an apparatus for providing device information according to a third embodiment of the present invention, such re-registration of the device information is not required.  
         [0057]      FIG. 7  is a table of device information stored in the device information database. As shown in  FIG. 7 , in the device information DB  103 , a flag  701  that indicates whether the entry is valid (Enable) or invalid (Disable) is provided for each entry of the device information. The monitoring unit  104  confirms existence of a device based on ICMP in a similar manner as in the second embodiment.  
         [0058]     The apparatus  100 , upon detecting a shutdown state of the device D, sets the flag  701  to invalid and nullifies the entry of the device D. The apparatus  100  notifies the shutdown state of the device D to the device B by the device information advertisement (UPnP byebye) message D 42 . Moreover, when the device information is referred through the information providing I/F  105 , the entry in the device information DB  103  of the device D having the invalid flag  701  is not displayed. Thus, the shutdown state of the device D can be notified to the device B and the device C.  
         [0059]      FIG. 8  is a sequence diagram of an operation to record and provide the device information according to a third embodiment of the present invention. In the third embodiment, a periodic monitoring of the device D, which is in the invalid condition, is maintained. Therefore, when the device D becomes alive again and responds with the ICMP (echo reply) message D 41 , the monitoring unit  104  of the apparatus  100  confirms the existence of the device D. The flag  701  is changed to indicate the valid condition in the device information DB  103  for the device D. The apparatus  100  outputs the device information D 44  and service information D 46  of the device D by the device information advertisement (UPnP discovery) message D 42 . Thus, the device information of the device D can be provided again to the device B.  
         [0060]     Because the device D becomes valid, the device C, when carrying out device information reference (HTTP-GET) D 47  and accessing the device information DB  103  via the information providing I/F  105 , can obtain device information D 48  of the device D.  
         [0061]     Thus, according to the third embodiment, when a state of the device D changes from the shutdown state to an alive state, the device information of the device D can be provided to the devices A to D without re-setting the device information via the setup UI  101 .  
         [0062]     In the third embodiment, the device information DB  103  is periodically monitored to confirm consistency between the device information in the device information DB  103  and actual device information, and if the device information in the device information DB  103  does not match with the actual device information, the device information DB  103  is updated to the latest device information. Furthermore, the latest device information is provided to the devices A to D on the in-home network  110  base on the automatic discovery protocol.  
         [0063]     If the devices A to D are operating in a dynamic host configuration protocol (DHCP) environment (in which a terminal address is automatically assigned), the IP addresses of the devices A to D change when the devices A to D are activated. In such environment, inconsistency between the device information in the device information DB  103  and the actual device information is occurs every time the devices A to D are activated. This leads to providing old or invalid device information to the devices A to D. According to a fourth embodiment of the present invention, the device information is updated according to a change of the IP address.  
         [0064]     The monitoring unit  104  periodically checks the IP addresses of the devices A to D that are registered in the device information DB  103 . The IP address and the MAC address of the devices A to D are managed in the device information DB  103  for each of the devices A to D. The IP address of each of the devices A to D may be changed every time each of the devices A to D is activated in the DHCP environment while the MAC address is basically constant and not changed. Using this characteristic, the IP addresses are confirmed based on an address resolution protocol (ARP). The ARP is a protocol to obtain the MAC address corresponding to the IP address.  
         [0065]      FIG. 9  is a flowchart of an address monitoring process according to the fourth embodiment.  FIG. 10  is a sequence diagram of an operation to update the device information according to the fourth embodiment. The apparatus  100  sends an ARP request related to the IP address of the devices A to D registered in the device information DB  103  (D 51  shown in  FIG. 10 ). Next, the device indicated by the IP address included in the ARP request (the devices C and D shown in  FIG. 10 ) returns an ARP response (D 52  shown in  FIG. 10 ). The apparatus  100  determines, based on a result of address confirmation, whether the device information in the device information DB  103  matches with the actual database information. In other words, the apparatus  100  checks whether the IP address and the MAC address included in the ARP response of the devices A to D match with the IP address and the MAC address in the device information DB  103  respectively (step S 901 ). If the addresses match each other (“YES” at step S 901 ), the apparatus  100  determines that the device information is registered properly and proceeds to step S 904 .  
         [0066]     If the addresses do not match, or if the ARP response message cannot be received (“NO” at step S 901 ), the apparatus  100  determines that the IP address is changed and obtains the latest IP address (step S 902 ).  
         [0067]     Because the MAC address is constant, the latest IP address is obtained based on a reverse ARP (RARP) (D 53  shown in  FIG. 10 ). The RARP is a protocol to obtain the IP address corresponding to the MAC address. When a correspondence between the IP address and the MAC address is not matching, an RARP message including the MAC address is sent to the in-home network  110 . The devices A to D having the MAC address or an RARP server (a server that responds instead of the devices A to D if the RARP is not supported by the devices A to D) sends an RARP response message, which includes the IP address corresponding to the MAC address, to the apparatus  100 .  
         [0068]     The apparatus  100 , upon receiving the RARP response message, determines that the IP address included in the RARP response message is the latest IP address, and updates the information corresponding to the IP address in the device information DB  103  (step S 903 ). Based on the latest information, the apparatus  100  provides the device information of the devices A to D to the devices A to D on the in-home network  110  via the UPnP message and the information providing I/F  105 . D 54  and D 55  shown in  FIG. 10  correspond to this process. Except for a device information deletion advertisement (UPnP byebye) in D 54 , D 54  is similar to D 42  to D 46  shown in  FIG. 8 . D 55  is similar to D 47  and D 48  shown in  FIG. 8 .  
         [0069]     Next, the apparatus  100  determines whether the IP addresses of all of the devices A to D registered have been confirmed (step S 904  of  FIG. 9 ). If the IP addresses of all the devices A to D have been confirmed (“YES” at step S 904 ), a first monitoring process is finished. If the IP address of any one of the devices A to D has not yet been confirmed (“NO” at step S 904 ), the apparatus  100  starts to monitor the next entry among the entries in the device information DB  103  (step S 905 ) and again executes the process shown in  FIG. 9  from step S 901 .  
         [0070]      FIG. 11  is schematic for illustrating update of information in the device information DB  103 . In information  1101  of the device D, the IP address is 192.168.0.50 and the MAC address is 02-EO-12-34-56-78.  
         [0071]     The apparatus  100  determines whether the addresses match the addresses obtained through the address confirmation at step S 901  shown in  FIG. 9 . If the MAC address included in the ARP response message differs from the MAC address of the information  1101  (for example, if MAC address is 02-EO-12-34-56-00 when the ARP is 192.168.0.50, or if there is no response), the apparatus  100  obtains the latest IP address at step S 902 . If IP address 192.168.0.60 is returned as the IP address corresponding to MAC address 02-EO-12-34-56-78 specified in the RARP response message, the device information DB  103  updates the IP address to the latest IP address to form information  1102  having IP address 192.168.0.60 and MAC address 02-EO-12-34-56-78 at step S 903 .  
         [0072]     According to the fourth embodiment, the apparatus  100  automatically updates the device information of the devices A to D even if the IP addresses of the devices A to D on the in-home network  110  change at each activation. Thus, re-registration of the device information by the user becomes unnecessary and the latest device information can be provided to the devices A to D.  
         [0073]     In the apparatus  100  according to the first to fourth embodiments, the user manually inputs the various items when inputting the device information of the devices C and D, which are UPnP incompatible, via the setup UI  101 . It is extremely difficult for an ordinary user to input the detailed setup data.  
         [0074]      FIG. 12  is schematic of an apparatus for providing device information according to a fifth embodiment of the present invention. The user inputs information on only simple items, such as manufacturer and device name, from the setup terminal  120 . A searching unit (not shown) is connected to a network such as Internet  1200  and accesses a device information DB server (a device setup information server on the network)  1201  that is connected to the Internet  1200  and holds the device information. The detailed device information on the device D is obtained from the device information DB server  1201  based on the information of the simple items (using as a search key) that are input by the user. The detailed device information obtained is stored in the device information DB  103 .  
         [0075]      FIG. 13  is a sequence diagram of an operation to record and provide the device information according to the fifth embodiment. The user inputs a device name (the device name of the device D in the example shown in  FIG. 13 ) into the apparatus  100  from the setup terminal  120  (D 61 ). Next, the apparatus  100  accesses the device information DB server  1201  via the Internet  1200  and notifies the device name (D 62 ). The device information DB server  1201  provides the detailed device information (detailed device information D 63 ) of the device corresponding to the device name to the apparatus  100 .  
         [0076]     The apparatus  100  performs a setup result notification (D 64 ) to the setup terminal  120  and stores the detailed device information in the device information DB  103 . Thus, the detailed device information of the device D can be provided to the devices A to D on the in-home network  110 . The device information of the devices A to D is provided to the devices A to D via the UPnP message and the information providing I/F  105  (D 65  and D 66 ). D 65  is similar to D 42  through D 46  shown in  FIG. 8  and D 66  is similar to D 47  and D 48  shown in  FIG. 8 .  
         [0077]     Thus, according to the fifth embodiment, the complicated input operations by the user can be simplified. Moreover, in the fifth embodiment, the detailed device information obtained from the device information data DB server  1201  via the Internet  1200  in response to the simple entries input by the user is notified to the user. A setup file of the device may be downloaded beforehand from the device information DB server  1201  on the Internet  1200  by the setup terminal  120  and the downloaded file can be uploaded by the setup UI  101 , thereby omitting the operations required for manual input by the user.  
         [0078]     The apparatus  100  collectively manages the device information of the devices A to D on the in-home network  110  and grasps the device information on all of the devices A to D on the in-home network  110 . Using the device information, services such as remote automatic upgrading of the firmware of the devices A to D or remote access to the devices A to D becomes possible.  
         [0079]     However, if the device information of all of the devices A to D on the in-home network  110  is made freely accessible, this can result in leakage of personal information.  
         [0080]      FIG. 14  is a schematic of a structure of an apparatus for providing device information according to a sixth embodiment of the present invention. The user randomly specifies whether to open the device information from the setup terminal  120 . Thus, the device information of each of the devices A to D is determined whether to be open or closed on a network. The apparatus  100  sends device information provision (D 71 ) to provide only the device information that is determined to be open by the user (the devices A and C in the example shown in  FIG. 14 ) to a service server  1401  on a network such as the Internet  1200  by a secure communication bus. Various network services (D 72 ) for the devices A to D on the in-home network  110  can be provided based on open device information provided.  
         [0081]     According to the sixth embodiment, the apparatus  100  can set whether to make the device information open to external devices via a network other than the in-home network  110 , such as the Internet  1200 . Thus, only the necessary device information of the devices A to D can be made open to the external source, thereby enabling to prevent leakage of personal information as well as the device information A to D. Thus, information security is enhanced.  
         [0082]     With the method and the apparatus for providing device information, both the devices A and B, which are UPnP compatible, and the devices C and D, which are UPnP incompatible, can obtain the device information of all of the devices A to D arranged on the in-home network  110 . The device information of the devices C and D can also be automatically updated according to a change in the condition of the devices. By providing a protocol conversion function, the devices C and D can receive the device information of the devices A and B and vice versa.  
         [0083]     The method of providing device information explained in the embodiments of the present invention can be implemented by executing a computer program prepared in advance by a computer, such as a personal computer and a workstation. The computer program is recorded on a computer-readable recording medium, such as a compact-disk read-only-memory, a magneto-optical disk, and a digital versatile disk, and is executed by the computer reading out from the recording medium. The computer program may be a transmission medium that is distributed through a network such as the Internet.  
         [0084]     According to the present invention, it is possible to provide device information of all of devices arranged on a network to both an automatic-discovery-process compatible device and an automatic-discovery-process incompatible device.  
         [0085]     Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.