JP4217663B2 - Service use device - Google Patents

Description

The present invention relates to a service equipment which is connected to a network service providing equipment utilizes services provided.

  Currently, there are many digital devices having a digital interface. This type of digital device is connected via a digital interface to construct a network. However, conventionally, one network is constructed with one type of interface, and it has been difficult to construct different types of interfaces as one network.

  In order to solve this problem, UPnP (Universal Plug and Play) is currently proposed (see, for example, Non-Patent Document 1). UPnP can use IP (Internet Protocol) to communicate between different interfaces to build a single network.

  FIG. 15 shows a configuration example of a UPnP network connected using a plurality of different interfaces. In FIG. 15, a plurality of devices are connected using IEEE1394, Power Line, and Home PNA that are wired interfaces and 802.11b that is a wireless interface to form one UPnP network.

  UPnP defines the functions of devices as services, and there are two devices on the UPnP network: “devices” that provide services and “control points” that control devices. For example, in FIG. 15, PC1, PC2, NotePC, and DTV can be used as control points to control the DVCR device. PC1 and PC2 are personal computers, Note PC is a notebook computer, DTV is a digital TV, and DVCR is a digital video camera.

  In UPnP, devices and control points use SSDP (Simple Service Discovery Protocol) to notify and detect services and the like. Notification of this service or the like is performed by transmitting a discovery message, and the discovery message is described using XML (Extensible Markup Language).

  When a device is connected to a UPnP network, it acquires an IP address from a DHCP server existing on the network, and multicasts the type of the device and the services that the device has as an ssdp: alive message. For example, when a device has a VTR function, the device describes information such as the type, recording format, and playback function of the corresponding recording medium in XML and transmits the information. Information such as supported recording media and recording formats are defined as state variables, and functions for performing device operations such as playback functions are defined as actions. When a device is disconnected from the UPnP network, it is recommended to multicast the ssdp: bye-bye message notifying that the device is disconnected. The ssdp: alive message describes the period during which the device or service notified by this ssdp: alive message is valid. If the ssdp: bye-bye message is not sent, the control point has passed the valid period received. By doing so, the corresponding service is invalidated.

  When a control point is connected to the network, it obtains an IP address from a DHCP server on the network and waits for a service notification from a controllable device, or requests a search for the required service. Detect devices by multicasting over the network. Each device on the UPnP network receives this search request, and the device having the search target service transmits a response to the control point.

The control point that has acquired the necessary service in this way inquires the device about the state variable and requests the action. The inquiry or action request is transmitted from the control point to the device using an HTTP request, and the result is transmitted from the device to the control point using an HTTP response.
Universal Plug and Play Device Architecture, Version 1.0, 08 Jun2000

  However, in the above conventional example, a value during which the device or service notified by the ssdp: alive message is valid is specified to be greater than 1800 seconds (30 minutes). Therefore, if the device leaves the network without sending an ssdp: bye-bye message due to a sudden power failure, the worst case is that the removal is not recognized by the control point for 30 minutes. . In addition, when the control point displays a connection state such as an icon, the display lasts for 30 minutes in the worst case, and the current connection state cannot be properly displayed.

The present invention has been made to solve the above problems, there when service providing apparatus connected to the network, such as detached from the network can not send a message indicating the leaving from the network even, and an object thereof is to provide a service using apparatus that is capable of recognizing that the speed Yakani the service providing apparatus is disconnected from said network.

One of the service use apparatuses according to the present invention is a service use apparatus that uses a service provided by a service providing apparatus connected to a network, and whether or not an ssdp: alive message has been received from the service providing apparatus. First determination means for determining; and device information acquisition means for acquiring device information including information related to the service providing apparatus from the service providing apparatus when the ssdp: alive message can be received from the service providing apparatus; whether the service providing device is a device for performing wireless communication, a second determination means for determining by using the device information, the service providing apparatus and the second determination that the device that performs wireless communication If a determination is made by means, ssdp: send to send a discover message Means, the ssdp: and a third determining means for determining whether or not received from the service providing device during the response to discover the message until the first time elapses, said the response first If it is not possible to receive from the service providing apparatus until one time has elapsed, it is determined that the service providing apparatus has left the network.
One of the service use apparatuses according to the present invention is a service use apparatus that uses a service provided by a service providing apparatus connected to a network, and whether or not an ssdp: alive message has been received from the service providing apparatus. First determination means for determining; and device information acquisition means for acquiring device information including information related to the service providing apparatus from the service providing apparatus when the ssdp: alive message can be received from the service providing apparatus; whether the service providing device is a device operated by a battery, and a second determining means for determining by using the device information, the service providing apparatus and the second determination that the device operated by a battery If a determination is made by means, ssdp: the discover main And a third determining means for determining whether or not received from the service providing device during the response to discover the message until the first time elapses,: transmitting means for transmitting the message, the ssdp When the response cannot be received from the service providing apparatus until the first time has elapsed, it is determined that the service providing apparatus has left the network.
One of the service use apparatuses according to the present invention is a service use apparatus that uses a service provided by a service providing apparatus connected to a network, and whether or not an ssdp: alive message has been received from the service providing apparatus. First determining means for determining, and second determining means for determining whether or not the service providing apparatus has been changed to a battery-operated apparatus when the ssdp: alive message can be received from the service providing apparatus. If, when the service providing device is determined to have been changed to a device operated by a battery by said second judging means, ssdp: transmitting means for transmitting the discover message, the ssdp: a response to the discover message first Before the time of 1 elapses. A third determination unit that determines whether or not the response can be received from the service providing device, and when the response cannot be received from the service providing device until the first time elapses, It is determined that the service providing apparatus has left the network.

According to the present invention, the service providing apparatus connected to the network, even if, as detached from the network can not send a message indicating the leaving from the network, fast Yakani the service providing apparatus There Ru can recognize that it has detached from the network.

Hereinafter, with reference to the accompanying drawings will be described implementation form of the present invention.

<First Embodiment>
A digital video camera as an example of a communication apparatus according to the first embodiment of the present invention will be described below with reference to FIG. The communication device according to the first embodiment of the present invention is not limited to a digital video camera, and may be a device such as a digital camera or an information terminal with a digital camera (including a mobile phone with a digital camera). In FIG. 1, 701 is a microphone, 702 is an audio signal processing unit, 703 is a lens unit, 704 is an image sensor such as a CCD, 705 is a camera signal processing unit, 706 is a compression / expansion unit, 707 is a recording / playback processing unit, and 708 is a recording unit. A reproduction head, 709 is a recording medium such as a magnetic tape, 710 is a stream processing unit, 711 is a digital interface unit (hereinafter referred to as DIF unit), 712 is a central processing unit (hereinafter referred to as CPU), and 713 is a wireless circuit. 714 is an antenna (hereinafter referred to as an RF circuit).

  The operation of the digital video camera having the above configuration will be described. The audio signal input to the audio signal processing unit 702 through the microphone 701 is input to the compression / decompression processing unit 706. An image signal formed by the lens unit 703 and output from the CCD 704 is input to the compression / expansion processing unit 706 in the same manner. During the photographing operation, the compression / decompression processing unit 706 performs a compression operation on the input image signal and audio signal. For example, the compression / decompression processing unit 706 performs DV compression processing for recording on a recording medium and MPEG-4 compression processing for DIF output. The compressed image signal and audio signal are subjected to recording processing in a recording / playback processing unit 707 and then recorded on a recording medium 709 via a head 708. When the compressed image signal and audio signal are wirelessly output to the outside, the compressed image signal and audio signal are input to the stream processing unit 710 to be packetized, and after being packetized, DIF The signal is output to the outside via the unit 711, the RF circuit 713, and the antenna 714.

Further, during the reproduction operation, the compression / decompression processing unit 706 performs an expansion operation. For example, assuming that data subjected to DV compression processing is recorded on the recording medium 709, the DV signal reproduced by the head 708 is reproduced by the recording / reproduction processing unit 707, and the compression / decompression processing unit 706 is obtained. DV decompression processing is performed at. The image signal after the DV expansion processing is sent to a display device (not shown) (for example, a display panel included in the video camera) and displayed. In addition, when the playback image is transmitted to the outside, the compression / decompression processing unit 706 performs, for example, MPEG-4 compression processing for DIF output. The MPEG-4 compressed image signal is input to the stream processing unit 710 to be packetized, and after being packetized, is output to the outside via the DIF unit 711, the RF circuit 713, and the antenna 714, respectively. . In the digital video camera of the present embodiment, DIF section 71 1 and the RF circuit 713, for example, a digital interface using a known wireless LAN technology by the IEEE802.11a standard (DIF). It goes without saying that other standards such as IEEE802.11b and IEEE802.11g may be used for this wireless LAN technology.

  Next, a digital television device (hereinafter referred to as a digital television) according to the present embodiment will be described with reference to FIG. In FIG. 2, a radio frequency (RF) signal is supplied to the RF input terminal 400 of the tuner 402. The tuner 402 selects individual signals under the control of the tuner control unit 404. The control unit 404 supplies a tuning control signal to the tuner 402 via the signal line 403, and supplies a band switching signal via the control bus 403 ′. The tuner control unit 404 is controlled by the microprocessor 410. The microprocessor 410 is a controller or microcomputer, and includes a central processing unit (CPU) 412, a read only memory (ROM) 414 and a random access memory (RAM) 416. The microprocessor 410 receives a control signal input by a user from an input switch (SW) 420 and an infrared (IR) receiver 422. The IR receiver 422 receives and decodes the remote control signal transmitted from the remote control transmitter 425.

  The tuner 402 generates an intermediate frequency (IF) signal and supplies it to the processing unit 430. The processing unit 430 comprises a video IF (VIF) amplification stage, an AFT circuit, a video detector and an audio IF (SIF) amplification stage. The processing unit 430 generates a baseband video signal (TV) and an audio carrier signal. The audio carrier signal is supplied to an audio signal processing circuit 435 including an audio detector and a stereo decoder. The audio signal processing circuit 435 generates left and right baseband audio signals and supplies them to a pair of speakers 438 to reproduce the audio.

  The baseband video signal (TV) output from the processing unit 430 is input to the switching unit 453. A video input terminal 442 (AUX input) is provided for receiving a baseband video signal from an external signal source. The input signal from the AUX input terminal 442 is supplied to the switching unit 453 similarly to the TV signal described above, and the output to the video signal processing circuit 455 is selected by the switching signal from the microprocessor 410. The video signal processing circuit 455 processes the input signal and finally displays it on a screen of a display device (not shown) such as a CRT. The video signal is also supplied to the sync separation circuit 460. The sync separation circuit 460 extracts a vertical sync signal and a horizontal sync signal from the video signal. The extracted vertical and horizontal synchronization signals are supplied to the microprocessor 410 and the deflection unit 470, and a deflection signal is generated and supplied to a yoke structure (not shown). Note that the display device is not limited to the CRT, and any device such as a liquid crystal method or a plasma method may be used, and a configuration for driving them will be apparent to those skilled in the art.

  Microprocessor 410 is coupled to a digital interface (DIF) unit 495. The DIF unit 495 is connected to the outside via an interface port (not shown). The DIF unit 495 is, for example, a digital interface using IEEE1394. An external command can be input using an IEEE1394 asynchronous communication method, and a video signal is input using an IEEE1394 isochronous communication method. The input video signal is appropriately processed by the DIF unit 495 and input to one terminal of the switching unit 453. As described above, the switching unit 453 can select and display one of the tuner input, the AUX input, and the DIF unit input. The signal from the tuner 402 is also input to the DIF unit 495. When the DIF unit 495 is controlled to be an external output, a signal from the tuner is output to the outside as an isochronous signal. A command using the above-described Asynchronous communication method is input to the microprocessor 410, and a control operation corresponding to the command is performed.

  Next, an example of a network connection mode according to the present embodiment will be described with reference to FIG. Reference numeral 300 denotes a digital video camera (video camera) according to the present embodiment, 302 denotes a digital television, and 304 denotes a wireless LAN access point (hereinafter referred to as an access point). As described above, in the video camera 300 according to the present embodiment, for example, a well-known wireless LAN technology is used according to the IEEE802.11a standard. Therefore, there is a physical connection between the video camera 300 and the access point 304 by wiring or the like. No connection has been made. However, the video camera 300 and the access point 304 can communicate with each other via a wireless LAN. On the other hand, the digital television 302 and the access point 304 are connected by IEEE1394, and communicate with each other using, for example, RFC2734 “IPv4 over IEEE 1394” standard. Of course, it goes without saying that the digital television and the access point of this embodiment may be connected using other communication methods such as Ethernet (registered trademark).

  In the present embodiment, the video camera 300 and the digital television 302 communicate with each other using, for example, a known TCP / IP protocol. At this time, the access point 304 controls the route of the TCP / IP packet as a router. In association with UPnP, the digital television 302 of this embodiment functions as a control point (CP), the video camera 300 functions as an Audio / Video (AV) device, and the access point 304 functions as an Internet Gateway device (IGD). In UPnP, “device” provides various services to “control point” on the network, and “control point” uses various services by performing various controls using “device” service. The function can be realized.

  When connection to the network is established by turning on the power or establishing a physical connection, the video camera 300, the digital television 302, and the access point 304 try to acquire an IP address. These devices first try to obtain an IP address from a DHCP server, for example according to the RFC 2131 “Dynamic Host Configuration Protocol” standard, so-called DHCP. If an IP address cannot be obtained by DHCP because there is no DHCP server on the network, the above device will send an Internet address "http://www.upnp.org/download/draft-ietf-zeroconf -IPv4-linklocal-01-Apr.txt "publicly known," Dynamic Configuration of IPv4 link-local addresses "standard for determining IP addresses Determines the IP address of the device using the so-called AutoIP standard .

  Next, the data exchange procedure of this embodiment will be described with reference to FIG. 4 is a sequence chart showing the operation of this embodiment using the ITU-T Recommendation Z.120, Message Sequence Chart standard. When the IP address is determined, the video camera 300 which is the device of the present embodiment transmits an Advertise message to all devices on the network by so-called broadcast. The Advertise message uses a message of the ssdp: alive format, and the above transmission form is called “Advertisement”. By this advertisement, the control point on the network can acquire information that the device or the service that the device has becomes effective, and information such as what service or device exists on the network. In this embodiment, the digital television 302 serving as a control point acquires function information and control information of the video camera 300 and the access point 304, or attribute information of the device, etc. by this advertisement.

  Next, the digital television 302 performs display for identifying and selecting the video camera 300 such as an icon on the display screen of the digital television based on the information acquired by the above-described advertisement. Thereafter, the digital television 302 designates the video camera 300, periodically transmits a search message, and starts a timer related to a response to the search message. As described above, the registration state of the device (video camera 300) is updated by the valid period (for example, 30 minutes) described in ssdp: alive, but the search message is repeatedly transmitted at shorter intervals. Will be.

  Usually, the video camera 300 returns a response message to the digital television 302 in response to the search message. However, if communication between the video camera 300 and the digital television 302 becomes impossible due to the video camera 300 going out of the wireless LAN reachable range, the search message does not reach the video camera 300. Times out. Based on the timeout information, the digital television 302 erases the display of the icon indicating the video camera 300 described above. With the above operation, even when the device is unexpectedly disconnected from the network or suddenly shuts down, the control point can quickly detect the state and reflect it on the display. The search operation by the search message, that is, the connection check process is performed by, for example, an ssdp: discover message using a known HTTP M-SEARCH method.

[Description of ssdp: alive]
As described above, ssdp: alive is a message signal transmitted from a device that has joined the network and indicating that the device is valid or that one of the services of the device is valid. When a device joins the network, the device uses ssdp: alive to make all devices on the network aware of the services it provides. The ssdp: alive message is transmitted using, for example, the NOTIFY method of GENA (General Event Notification Architecture) on the SSDP multicast channel. GENA is a known protocol by the document “GeneralEventNotification Architecture Base: Client to Arbiter” published at the Internet address “http://www.upnp.org/download/draft-cohen-gena-client-01.txt”. It is a protocol for sending and receiving event messages. In GENA, devices or devices that transmit and receive messages are called publishers and subscribers. The subscriber requests, updates, and cancels the event issuance reservation. The publisher also issues events. Thus, in GENA, an event is transmitted from a publisher to a subscriber. The SSDP is a protocol for discovering resources based on HTTP on a local area network (LAN). SSDP is a well-known protocol according to the document “SimpleServiceDiscovery Protocol / 1.0” published on the Internet address “http://www.upnp.org/download/draft_cai_ssdp_v1_03.txt”.

As described above, when a device joins the network, the device announces that the SSDP service exists by sending a message using the NOTIFY method on the SSDP multicast channel. The message includes data on the request line of the message indicating that the message is a GENA message. The request line is, for example,
NOTIFY * HTTP / 1.1
It is like this.

  The ssdp: alive message includes a header as additional information. Table 1 shows the contents of the header of the ssdp: alive message.

  The expiration information provided by the Cache-control header in Table 1 informs the control point how long information about the service must be retained in the cache memory of the control point. . When this period expires, the control point must discard the information from the control point cache. The ssdp: alive message described above is also used to indicate to the control point that the device service is continuously available before the cache memory entry is deleted due to expiration. .

[Description of ssdp: discover]
As described above, the ssdp: discover request uses the well-known HTTP method M-SEARCH and includes the search target ST in the header of the ssdp: discover message. The client sets the type of service that the client wants in the ST. An ST can specify an access point or other device. It is not allowed to include multiple ST headers in one ssdp: discover message. Also, complex searches such as logical operations and name / value pairs are not supported as well. The request line of the ssdp: discover message is, for example, an M-SEARCH request line with “*” indicating that a search is performed for all listed devices in the Request-URI. For example,
M-SEARCH * HTTP / 1.1
become that way.

  UPnP control points and devices use the SSDP URI search capability, but also use special conventions for the ST header in the ssdp: discover message. By setting different values in the ST header in the ssdp: discover message, the UPnP control point can search for all devices, root devices, specified device types, specified service types, and the like. Table 2 shows the headers used for SSDP requests.

  Once the searched device or service is detected, a response message to the ssdp: discover message is directly transmitted as a unicast message to the transmission device of the ssdp: discover message. At this time, the ssdp: discover message includes period information and location information in addition to the service type and the unique service name of the service to be searched. Table 3 shows headers used in response to the ssdp: discover message.

  For UPnP devices, the USN field takes a number of different formats depending on the type of request contained in the ST header in the initially transmitted ssdp: discover message. The format of the ST header is shown in Table 4 below.

FIG. 5 is a flowchart for explaining connection confirmation processing at a control point according to the first embodiment. In the above example, one device (video camera 300) is connected to the network. However, it goes without saying that a plurality of devices may be connected. The following extended to the case of a plurality of devices illustrating the connection check processing. First, in step S101, it is determined whether an Advertise message has been received. When the Advertise message is received, the process proceeds to step S102, and information about the device is acquired from the Advertise message. In step S103, device connection registration (cache registration) and icon display are performed. If the device is already registered when the Advertise message is received, the registration period is updated.

  In step S104, it is determined whether or not it is time to execute the connection check process using the search message. If it is not the execution timing, the process returns to step S101. If it is the execution timing, the connection check processing in steps S105 to S109 is executed.

  In step S105, a timer is started, and in step S106, the search message described above is transmitted to the device to which connection is registered. The device that has responded to the search message transmitted in step S106 is held until the time up time of the timer activated in step S105 is reached (steps S107 and S108). If there is a device that does not respond to the search message when the time is up, it is determined that the device has left the network, and the icon display of the device is deleted. In the connection check process, the connection check process is collectively performed for the devices registered for connection. However, it is obvious that the check may be performed by individually starting a timer.

  By repeating the above processing, it is possible to check at the connection check execution timing that the device has left the network for some reason. By setting the execution timing of this connection check to be shorter than the valid period of the device, it is possible to control icon display and the like in accordance with the actual network connection state.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 6 and the like, “loop” indicates that this part is repeatedly executed, and “alt” indicates a process when the repetition process is terminated. In the first embodiment, the connection check is executed unconditionally for the device , but in the second embodiment, the execution of the connection check is controlled according to the drive mode of the device . For example, when a device is connected to a network by wireless communication, the device may be carried out of the wireless area. That is, in the case of wireless communications, even though the user does not intend to cut with the network, the connection to the network is likely to expire, configured to perform a connection check in this case To do.

  FIG. 6 shows a sequence chart of control points and devices according to the second embodiment using the Message Sequence Chart standard as in FIG. The connection form in the second embodiment is the same as that in FIG. 3, and FIG. 6 describes the sequence after the IP address is determined using DHCP or AutoIP.

When the IP address is determined, the video camera 300 which is the device of the present embodiment transmits an Advertise message to all devices on the network by so-called broadcast. As in the first embodiment, the Advertise message is performed using a message in the ssdp: alive format, that is, in the transmission form of Advertisement. This Advertisement, digital television is a control point 302 obtains various information as in the first embodiment with respect to the video camera 30 0 is a device.

  When the Advertise ends, the digital television 302 performs display for identifying and selecting the video camera 300 such as an icon on the display surface of the digital television based on the information acquired by the Advertisement. Next, the digital television 302 attempts to acquire a DeviceDescription from the video camera 300 using, for example, an HTTP GET method. In response to the GET request, the video camera 300 transmits the DeviceDescription of the own device. If there is a description in this DeviceDescription that the video camera 300 is equipped with a digital interface 711 using radio, the device (the video camera 300) is described in the first embodiment. Check the connection properly. That is, the digital television 302 performs a search operation, that is, a connection check process by designating the video camera 300 and periodically transmitting a search message. The operation in the connection check process is the same as in the first embodiment.

  In the above example, the case where connection confirmation is performed according to whether or not the device is a wireless digital interface has been described. However, the determination of whether or not to perform connection confirmation is not limited to this. For example, if the connection is confirmed when the device is battery-powered, it is possible to cope with a sudden power interruption due to battery consumption.

  A case where the device according to the present embodiment is battery-driven will be described with reference to FIG. FIG. 7 also shows a sequence chart of control points and devices according to the present embodiment using the Message Sequence Chart standard as in FIG. Also in FIG. 7, the connection form is the same as in FIG. 3, and the sequence after the IP address is determined using DHCP or AutoIP is shown. Further, FIG. 7 shows almost the same sequence as FIG. 6, except that the video camera 300 is battery-driven, and that information is transmitted to the control point using DeviceDescription, and the power is cut off due to the battery being removed. The operation is different when the operation of the video camera 300 is disabled due to a voltage drop due to battery use.

  When the IP address is determined, the video camera 300 transmits an Advertise message to all devices on the network by so-called broadcast. The acquisition of night information in the Advertise message is as described above.

  When Advertise ends, the digital television 302 of the present embodiment performs display for identifying and selecting the video camera 300 such as an icon on the display surface of the digital television based on the information acquired by the above-described Advertisement. Next, the digital television 302 tries to acquire the DeviceDescription from the video camera 300 using the HTTP GET method. In response to the GET request, the video camera 300 transmits the DeviceDescription of the own device. If the DeviceDescription describes that the video camera 300 is battery-powered, the connection check process is executed. With such an operation, even when the device is unexpectedly disconnected from the network or suddenly powered off, the control point can quickly detect the state and reflect it on the display.

Further, in the second embodiment, the cause of the device can be grasped to some extent when the connection check process detects the disconnection from the network by recognizing the drive form of the device . For example, for a device connected by wireless communication, there is a high possibility that the cause of leaving the network has gone out of the wireless area. Therefore, when the connection check process recognizes such a device detachment, a message such as “This device may have gone out of the wireless area” may be displayed. Similarly, if the device is confirmed to be driven by a battery, a message such as “This device may have a low battery voltage” can be displayed.

It should be noted that the display of the withdrawal factor as described above can also be applied in the first embodiment. For example, in the first embodiment, the GET method is used to obtain drive mode information such as whether the interface is wireless or battery-driven, and when a timeout occurs, the above-described operation is performed based on the drive mode information of the device. A message may be displayed.

[Explanation on obtaining Device Description]
As described above, the control point acquires the above-described Device Description by issuing a known HTTP GET method. In order to acquire DeviceDescription, the control point uses the URL information in the above-mentioned Advertisement message or the URL information in the response from the device to the ssdp: discover message. In response to the GET method, the device transmits a DeviceDescription included in the body of the HTTP response to the control point. This DeviceDescription is described using, for example, the Extensible Markup Language (hereinafter referred to as XML) standard which is a recommendation of the World Wide Web Consortium (W3C). The DeviceDescription is described as follows, for example.

  <Description Example 1 (Example of Device Descritpion)>

  In the above description 1, whether or not the device is battery-powered can be identified by the character string enclosed by the tags <power> and </ power>. For example, when the character string is “battery”, the control point recognizes that the device is battery-powered. In this case, the control point is configured to periodically transmit the ssdp: discover message. In this embodiment, the tags <power> and </ power> are used, but it may be configured to identify whether or not the battery is driven by using other tags. For example, using tags <batteryPower> and </ batteryPower> that take a logical value as the value, battery drive is used when the internal value is the logical value “true” or “1”, and battery drive is used when the value is “false” or “0” You may comprise so that it may not exist. It goes without saying that the same effect can be obtained even if other tags are defined.

  FIG. 8 is a flowchart for explaining connection confirmation processing at a control point according to the second embodiment. Steps in which the same processing as in FIG. 5 is executed are denoted by the same reference numerals.

  When device registration and icon display are performed in steps S101 to S103, a device description for the device is acquired, and it is determined from the description whether the device should be subjected to a connection check (steps S201 and S202). In the above-described embodiment, two cases where (A) the device is communicating via a wireless digital interface and (B) the device is battery-driven are individually described. The connection check may be executed based on a combination (for example, when (A) and (B) are established, or when either (A) or (B) is established). Further, it may be determined whether or not the connection check needs to be executed using other conditions. If it is determined that the device is to execute the connection check, in step S203, the device is registered in the connection check target list.

  Thereafter, when it is time to execute a connection check, the process proceeds to step S205, and the connection check process described in steps S105 to S110 is executed. Since the target of the connection check process is a device registered in the connection check target list, the search message transmission target device in step S106 is a device registered in the connection check target list. In step S110, the registration of the device that has not responded is also deleted from the connection check target list.

  As described above, according to the second embodiment, a device that may be unexpectedly disconnected from the network is detected, and the connection check is performed on the detected device. And network congestion will not occur. Whether or not the connection check can be executed may be determined based on whether or not it is portable.

<Third Embodiment>
In the second embodiment, Device Description is used to identify whether or not the device is battery-powered at the time of device registration, but other means are used to notify that the device is battery-powered. You may do it. For example, by using the event notification function, the ssdp: discover message is sent by notifying the control point of a change from battery operation to AC power supply or from AC power supply to battery drive during device operation. You may comprise so that it may transmit regularly. In this way, it is possible to perform control such that switching between AC power supply driving and battery driving is detected, and the above-described connection check process is started when switching to battery driving is performed. In the third embodiment, such processing will be described.

FIG. 9 is a diagram illustrating an embodiment when the video camera 300 as a device dynamically changes from AC power supply drive to battery drive. When the IP address is determined, the video camera 300 which is the device of the present embodiment transmits an Advertise message to all devices on the network by so-called broadcast. Similar to the first embodiment and the second embodiment, the Advertise message is performed using a message of the ssdp: alive format, that is, in the transmission form of Advertisement. This Advertisement, digital television is a control point 302 obtains various information as in the first embodiment with respect to the video camera 30 0 is a device.

  When Advertise ends, the digital television 302 of the present embodiment performs display for identifying and selecting the video camera 300 such as an icon on the display surface of the digital television based on the information acquired by the above-described Advertisement. Next, the digital television 302 uses an HTTP SUBSCRIBE method to perform control so that an event is issued when the power supply driving state of the video camera 300 changes. The SUBSCRIBE method includes information (description) as in the following description example 2, for example.

  <Description example 2 (example of SUBSCRIBE data transmitted by digital TV)>

  In response to the SUBSCRIBE request, the video camera 300 returns a Response including information (description) as shown in the following description example 3, for example.

  <Example 3 (Example of response to SUBSCRIBE method sent by video camera)>

  Thereafter, when the power supply state of the video camera 300 changes from, for example, AC power supply drive to battery drive, the video camera 300 of the present embodiment issues an event using the NOTIFY method to the digital television that is the control point. The event includes, for example, information (description) as shown in the following description example 4.

  <Description Example 4 (example of event data transmitted by video camera)>

  When the video camera 300 that detects that the video camera 300 is changed to battery-powered operation according to the XML description information included in the body in the event issues the NOTIFY method to the digital television 302, the digital television 302 Designates the video camera 300, periodically transmits a search message, and starts a timer related to a response to the search message. The information included in the event may be information (description) as described in the description example 5.

  <Description Example 5 (Another example of event data transmitted by the video camera)>

  That is, in the description example 4, the power type (battery) is described between the tags <power> and </ power>, and in the description example 5, the authenticity is described between the tags <batteryPower> and </ batteryPower>. is doing. Of course, other methods may be used, and it is needless to say that the digital television 302 (control point) can detect that the video camera 300 has changed to the battery-powered state.

  The device connection check process by transmitting the search message is as described in the first and second embodiments.

  FIG. 10 is a flowchart for explaining connection confirmation processing at a control point according to the third embodiment. Steps in which the same processing as in FIGS. 5 and 8 is executed are denoted by the same reference numerals.

When device registration and icon display are performed in steps S101 to S103, in step S301, issuing a NOTIFY method for the device is instructed using SUBSCRIBE (Subscribe: reuest and Subscribe: response in FIG. 9). This instruction, in those 該De device, for example, when the power supply is changed to the battery, it is notified to the control point (incorporating the instruction content to spill notify when battery in advance by the Notify deep).

Thereafter, when Notify is received from the device, the process proceeds from step S302 to step S303, and it is determined whether or not to execute a connection check. For example, the driving of the device is when receiving the Notify indicating a battery, the process proceeds from step S303 to step S304, and registers the device to the connection target list. Although not shown, when Notify notifies that the device is driven by an AC power source, the device may be excluded from the connection check target list. Then, in steps S104 and S205, connection check processing is started for devices registered in the connection target check list among devices registered for connection to the network.

<Fourth embodiment>
In the second and third embodiments, the execution of the connection check is controlled according to the drive mode (battery drive, wireless communication, etc.), but in the fourth embodiment, the connection check is executed based on the radio wave intensity in the wireless communication. Control.

  In FIG. 11, the same reference numerals as those in FIG. 2 indicate the same functions. The difference between FIG. 11 and FIG. 2 is the presence of an RF circuit 500 and an antenna 505. As described above, the DIF unit 495 and the RF circuit 500 are DIFs using a wireless LAN technology known according to the IEEE 802.11a standard, for example. Needless to say, other wireless standards such as IEEE802.11b and IEEE802.11g may be used.

  Signals from the DIF unit 495 and the RF circuit 500 are transmitted / received to / from an external device via the antenna 505, and the radio wave intensity is measured by the RF circuit 500 and input to the CPU 419 via the DIF unit 495. When the radio field intensity used for communication with an external device that is transmitting and receiving signals becomes weaker than a predetermined value, the CPU 419 passes the external signal through the DIF unit 495, the RF circuit 500, and the antenna 505. It operates to start a device search (connection confirmation in the first and second embodiments).

  An example of a network connection mode according to the fourth embodiment will be described with reference to FIG. 12, the same reference numerals as those in FIG. 3 indicate the same functions. As described above, in the video camera 300 according to the present embodiment, for example, a well-known wireless LAN technology is used according to the IEEE 802.11a standard. Therefore, there is a physical connection between the video camera 300 and the digital television 306 by wiring or the like. No connection has been made. However, the video camera 300 and the digital television 306 can communicate with each other via a wireless LAN. In the present embodiment, the video camera 300 and the digital television 306 communicate with each other using, for example, a known TCP / IP protocol. With regard to UPnP, the digital television 306 of this embodiment functions as a control point (CP), and the video camera 300 functions as an Audio / Video (AV) device. In UPnP, the device provides various services to the control point on the network, and the control point performs various controls using the service of the device to perform various network service functions. It can be realized.

  When connection to the network is made by turning on the power or establishing a physical connection, the video camera 300 and the digital television 306 of this embodiment try to acquire an IP address. These devices first attempt to obtain an IP address from a DHCP server, for example according to the RFC 2131 “Dynamic Host Configuration Protocol” standard, so-called DHCP. If an IP address cannot be obtained by DHCP because there is no DHCP server on the network, the above device will send an Internet address "http://www.upnp.org/download/draft-ietf-zeroconf -IPv4-linklocal-01-Apr.txt "publicly known," Dynamic Configuration of IPv4 link-local addresses "standard for determining IP addresses Determines the IP address of the device using the so-called AutoIP standard .

  Next, the connection check process according to the fourth embodiment will be described with reference to FIG. FIG. 13 is a sequence chart showing an operation according to this embodiment using the ITU-T Recommendation Z.120, Message Sequence Chart standard.

When the IP address is determined, the video camera 300 which is the device of the present embodiment transmits an Advertise message to all devices on the network by so-called broadcast. As in the first embodiment, the Advertise message is performed using a message in the ssdp: alive format, that is, in the transmission form of Advertisement. This Advertisement, digital television 30 6 is a control point acquires the first embodiment similarly to various kinds of information with respect to the video camera 30 0 is a device.

  When the Advertise ends, the digital television 306 of the present embodiment performs display for identifying and selecting the video camera 300 such as an icon on the display surface of the digital television based on the information acquired by the Advertisement. The digital television 306 measures the intensity of radio waves used for communication with the video camera 300 as described above at regular intervals. For example, the radio field intensity may be measured by a received voltage of a preamble portion added before actual data, or may be measured by a received voltage of training data. When the radio field intensity is lower than a predetermined constant intensity or when the radio field intensity is below a predetermined value, the connection check process described in the first to third embodiments is executed.

  A control point processing flow according to the fourth embodiment is shown in FIG. The same steps as those in FIGS. 5 and 8 are given the same step numbers. In step S401, communication is performed with each device for which connection is registered, and each received radio wave intensity is checked. If there is a device whose received radio wave intensity is lower than a predetermined value in steps S402 and S403, it is registered in the connection check target list.

In the fourth embodiment, the digital TV 306 and the video camera 300 directly communicate with each other via a wireless LAN, but a relay device such as a wireless LAN access point may be interposed between them. In this case, the digital television is a control point 306 for acquiring data about radio intensity between the video camera 300 is the relay device and the device from the relay device. The information on the radio wave intensity is transmitted / received by using, for example, the event (Notify) mechanism described in the third embodiment.

  An example of the operation will be described with reference to FIG. However, the wireless LAN access point 304 and the digital television 302 may be connected by a wireless digital interface or may be connected by a wired interface. The digital television 302 controls the access point 304 to issue an event when the radio wave state between the video camera 300 and the access point 304 changes using the HTTP SUBSCRIBE method. When the radio wave state falls below a predetermined value, the access point 304 issues an event indicating that the radio wave state has deteriorated to the digital television 302. Receiving the event, the digital television 302 designates the video camera 300 and periodically transmits a search message to execute a connection check process.

  The processing procedure using the control points in this case will be described with reference to FIG. In the notification in step S301, a request (a notification request for a device whose radio field intensity falls below a predetermined value) is issued to the relay apparatus. In step S302, when a device whose radio field intensity has decreased due to Notify is received from the relay apparatus, the device is registered in the connection check target list in step S304.

  A process for receiving a notification that the reception strength has been recovered by Notify and excluding the device from the connection check target list may be provided.

  As described above, according to the fourth embodiment, since it is determined whether or not to check the connection according to the radio wave condition, the connection check is executed for a device that is likely to leave the network. Therefore, useless connection check processing can be avoided, and processing efficiency and network utilization efficiency are improved.

<Other embodiments>
In each of the above embodiments, the control point is a digital television and the device is a video camera, but it is needless to say that the present invention is not limited to this combination.

  Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in the.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

1 is a block diagram illustrating a digital video camera according to a first embodiment. It is a block diagram which shows the digital television by 1st Embodiment. It is a figure which shows the example of a connection of 1st Embodiment. It is a sequence chart which shows the data transfer procedure of 1st Embodiment. It is a flowchart explaining the connection check process by 1st Embodiment. It is a sequence chart which shows the data transfer procedure by 2nd Embodiment. It is a sequence chart which shows the data transfer procedure by the modification of 2nd Embodiment. It is a flowchart explaining the connection check process by 2nd Embodiment. It is a sequence chart which shows the data transfer procedure by 3rd Embodiment. It is a flowchart explaining the connection check process by 3rd Embodiment. It is a block diagram which shows the structure of the digital television in 4th Embodiment. It is a figure which shows the example of a connection of 4th Embodiment. It is a sequence chart which shows the data transfer procedure by 4th Embodiment. It is a flowchart explaining the connection check process by 4th Embodiment. It is a figure which shows the structural example of the network of UPnP connected using the several different interface.

Claims (15)

A service using device that uses a service provided by a service providing device connected to a network,
ssdp: first determination means for determining whether an alive message has been received from the service providing apparatus;
Device information acquisition means for acquiring device information including information related to the service providing apparatus from the service providing apparatus when the ssdp: alive message is received from the service providing apparatus;
Second determination means for determining whether the service providing apparatus is an apparatus that performs wireless communication, using the device information;
When the second determination unit determines that the service providing device is a device that performs wireless communication, a transmission unit that transmits a ssdp: discover message;
Third determination means for determining whether or not a response to the ssdp: discover message has been received from the service providing apparatus until a first time has elapsed,
The service using apparatus, wherein if the response is not received from the service providing apparatus before the first time elapses, it is determined that the service providing apparatus has left the network. The service utilization apparatus according to claim 1, wherein the device information acquisition unit acquires the device information from the service providing apparatus using URL information included in the ssdp: alive message. If the response can be received from the service providing apparatus before the first time elapses, the first determination means has received the ssdp: alive message from the service providing apparatus again. The service use apparatus according to claim 1, wherein the service utilization apparatus performs the determination. A display unit for displaying an icon corresponding to the service providing apparatus;
The display of the icon is erased when the response cannot be received from the service providing apparatus before the first time elapses. 4. The service utilization apparatus as described. The service providing apparatus is a device in UPnP,
The service using apparatus, the service using apparatus according to claim 1, any one of 4, which is a control point in UPnP. A service using device that uses a service provided by a service providing device connected to a network,
ssdp: first determination means for determining whether an alive message has been received from the service providing apparatus;
Device information acquisition means for acquiring device information including information related to the service providing apparatus from the service providing apparatus when the ssdp: alive message is received from the service providing apparatus;
Second determination means for determining whether or not the service providing apparatus is an apparatus operated by a battery, using the device information;
When the second determination unit determines that the service providing device is a battery-operated device, a transmission unit that transmits a ssdp: discover message;
Third determination means for determining whether or not a response to the ssdp: discover message has been received from the service providing apparatus until a first time has elapsed,
The service using apparatus, wherein if the response is not received from the service providing apparatus before the first time elapses, it is determined that the service providing apparatus has left the network. The service utilization apparatus according to claim 6 , wherein the device information acquisition unit acquires the device information from the service providing apparatus using URL information included in the ssdp: alive message. If the response can be received from the service providing apparatus before the first time elapses, the first determination means has received the ssdp: alive message from the service providing apparatus again. service using apparatus according to claim 6 or 7, characterized in that the Kano determination. A display unit for displaying an icon corresponding to the service providing apparatus;
The If you are unable to receive a response from the service providing device until the elapse of the first time, to any one of claims 6 8, characterized in that to erase the display of the icons The service utilization apparatus as described. The service providing apparatus is a device in UPnP,
The service using apparatus, the service using apparatus according to any one of claims 6 9, characterized in that the control point in UPnP. A service using device that uses a service provided by a service providing device connected to a network,
ssdp: first determination means for determining whether an alive message has been received from the service providing apparatus;
Second determination means for determining whether or not the service providing apparatus has been changed to a battery-operated apparatus when the ssdp: alive message can be received from the service providing apparatus;
When the second determination unit determines that the service providing apparatus has been changed to a battery-operated apparatus, a transmission unit that transmits a ssdp: discover message;
Third determination means for determining whether or not a response to the ssdp: discover message has been received from the service providing apparatus until a first time has elapsed,
The service using apparatus, wherein if the response is not received from the service providing apparatus before the first time elapses, it is determined that the service providing apparatus has left the network. 12. The service use apparatus according to claim 11 , wherein the second determination unit determines whether or not the service providing apparatus is changed to an apparatus that operates by a battery, based on a notification from the service providing apparatus. . If the response can be received from the service providing apparatus before the first time elapses, the first determination means has received the ssdp: alive message from the service providing apparatus again. service using apparatus according to claim 11 or 12, characterized in that the Kano determination. A display unit for displaying an icon corresponding to the service providing apparatus;
Wherein if a response was not received from the service providing device until the elapse of the first time, in any one of claims 11 to 13, characterized in that to erase the display of the icons The service utilization apparatus as described. The service providing apparatus is a device in UPnP,
The service utilization apparatus according to any one of claims 11 to 14 , wherein the service utilization apparatus is a control point in UPnP.

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