JP2012178881A - Communication device and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device and a communication method that can start the media control protocol in an appropriate quality setting state.SOLUTION: A communication device performs the session control protocol, establishes a session to perform the media control protocol used for distribution control of data, and after the session has been established, performs the media control protocol; thus, it performs communication regarding distribution control of data on the session. In addition, when the session is established, the communication device determines and transmits a session identifier to identify the session to a network, and performs communication on a session identified by the determined session identifier.

Description

  The present invention relates to a media distribution technique via a quality assurance network.

  In a quality assurance network typified by NGN (Next Generation Network), session quality control (QoS (Quality of Service)) is controlled by a session control protocol typified by SIP (Session Initiation Protocol: see Non-Patent Document 1). Is done. This quality control includes bandwidth control and priority control, which are accompanied by authentication.

  Communication quality is related to service quality, such as video playback quality, and billing for communication. If the communication quality is high, the quality of service to the user is high, while the fee charged to the user is also high.

  Until now, quality assurance networks have often been used for telephone services that make two-way calls. In such a telephone service, bidirectional media transmission / reception is realized in one session.

  However, it is conceivable to use a quality assurance network for video distribution services in addition to telephones. The video distribution service is a service that distributes video to a user's receiver from a distribution server that stores video data, and causes the receiver to reproduce the video. A media control protocol and a media distribution protocol are used to realize the video distribution service. Therefore, the session control protocol controls a plurality of sessions in order to realize one service.

  FIG. 11 is a block diagram illustrating a configuration of a communication system that distributes video via a quality assurance network. Referring to FIG. 11, the communication system includes a distribution server 91 and a receiver 92. The distribution server 91 and the receiver 92 are connected via a quality assurance network 93. For example, the receiver 92 requests the distribution server 91 to distribute the video, and the distribution server 91 distributes the video to the receiver 92 in response to the request. The video distribution is realized by a media control protocol typified by RTSP (Real Time Streaming Protocol) and a media distribution protocol typified by RTP (Real time Transport Protocol).

  The media control protocol is a protocol for controlling the state of video distribution such as video playback, stop, and recording. The representative RTSP is generally mounted on TCP (Transmission Control Protocol).

  The media distribution protocol is a protocol for actually transferring video data. The representative RTP is generally implemented on UDP (User Datagram Protocol).

  The distribution server 92 and the receiver 91 are implemented with a media control protocol, a media distribution protocol, and a session control protocol for controlling those sessions. The session control protocol performs session control to guarantee the communication quality of the media control protocol and the media distribution protocol. For example, it is conceivable that priority control of the media control protocol and bandwidth securing control of the media distribution protocol are performed.

RFC3261-SIP: Session Initiation Protocol, June 2002

  As a starting procedure of these protocols, first, the session control protocol is started, the session description is notified to the quality assurance network 93, and the session can be controlled. The protocol is started. In the above-described example of the video distribution service, the control targets by the session control protocol are the media control protocol and the media distribution protocol.

  Among the control targets of the session control protocol, the media control protocol is implemented on TCP as described above. In TCP, a transmission source port number is determined when a TCP handshake is started. Therefore, until the TCP handshake is started, the media control protocol session cannot be specified by the port number, and the session control protocol cannot control quality setting or the like for the media control protocol session.

  An object of the present invention is to provide a communication device and a communication method capable of starting a media control protocol with an appropriate quality setting.

In order to achieve the above object, a communication apparatus of the present invention executes a session control protocol and establishes a session for executing a media control protocol used for data distribution control;
After the session is established by the session control protocol execution unit, a media control protocol execution unit that performs communication related to distribution control of the data on the session by executing the media control protocol,
The session control protocol execution unit, when establishing the session, determines a session identifier for identifying the session, and transmits to the network,
The media control protocol execution unit is configured to perform communication on a session specified by the determined session identifier.

On the other hand, the communication method of the present invention executes a session control protocol and establishes a session for executing a media control protocol used for data distribution control;
Performing communication related to data distribution control on the session by executing the media control protocol after the session is established in the step of establishing the session, and
In the step of establishing the session, when establishing the session, a session identifier for identifying the session is determined and transmitted to the network;
In this method, communication is performed on a session specified by the determined session identifier.

  According to the present invention, it is possible to start a media control protocol with an appropriate quality setting.

It is a block diagram which shows the structure of the communication system by this embodiment. It is a sequence diagram which shows operation | movement when the video delivery in the communication system by this embodiment is started. It is a block diagram which shows the structure of the delivery server by this embodiment. It is a block diagram which shows the structure of the receiver by this embodiment. It is a sequence diagram which shows operation | movement of the communication system in a 1st Example. It is a sequence diagram which shows operation | movement of the communication system in a 2nd Example. It is a sequence diagram which shows operation | movement of the communication system in a 3rd Example. It is a sequence diagram which shows operation | movement of the communication system in a 4th Example. It is a sequence diagram which shows operation | movement of the communication system in a 5th Example. It is a sequence diagram which shows operation | movement of the communication system in a 6th Example. It is a block diagram which shows the structure of the communication system which distributes an image | video via a quality assurance type network.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a communication system according to the present embodiment. Referring to FIG. 1, the communication system includes a distribution server 11 and a receiver 12. The distribution server 11 and the receiver 12 are connected to each other via a quality assurance network 13. The quality assurance network 13 is a network that guarantees the set quality by setting the bandwidth and priority reserved for communication.

  The receiver 12 requests video distribution to the distribution server 11 via the quality assurance network 13, and the distribution server 11 distributes video to the receiver 12 via the quality assurance network 13 in response to the request. At that time, the quality set for the communication between the receiver 12 and the distribution server 11 is guaranteed by the quality assurance network 13.

  Such a video distribution service is realized by two protocols related to media distribution such as a media control protocol represented by RTSP and a media distribution protocol represented by RTP. A session is established for each of these protocols, and quality can be set for each session.

  The distribution server 12 and the receiver 11 are mounted with a media control protocol, a media distribution protocol, and a session control protocol represented by SIP that controls those sessions.

  FIG. 2 is a sequence diagram showing an operation when video distribution is started in the communication system according to the present embodiment. When starting the video distribution, the distribution server 12 and the receiver 11 first start executing the session control protocol. The distribution server 12 and the receiver 11 establish a session for the media control protocol and a session for the media distribution protocol by the session control protocol (step 101). At this time, the session control protocol determines a session identifier for specifying a session of the media control protocol.

  By determining the session identifier of the media control protocol, it becomes possible to control the session by specifying the media control protocol. In this state, the distribution server 12 and the receiver 11 may perform control for setting quality such as priority control of the session of the media control protocol as part of the session establishment before the start of the media control protocol or after the session establishment. Good (step 102). By appropriately setting the priority of the media control protocol, it is possible to ensure the responsiveness in executing the media control from the start of the media control protocol.

  In this embodiment, since the media distribution protocol is implemented on UDP, it is possible to specify a session by a port number before the start. Therefore, even if the session control protocol does not determine the session identifier of the media distribution protocol, control that identifies the session of the media distribution protocol is possible. In this state, the distribution server 12 and the receiver 11 may appropriately set the quality such as the reserved band of the media distribution protocol.

  Subsequently, the distribution server 12 and the receiver 11 perform media control using a media control protocol in accordance with a user operation on the receiver 11 (step 103). According to the media control, video is distributed from the distribution server 12 to the receiver 11 by the media distribution protocol (step 104). The receiver 11 reproduces the video received from the distribution server 12.

  FIG. 3 is a block diagram showing the configuration of the distribution server according to the present embodiment. Referring to FIG. 3, the distribution server 12 includes a session control protocol execution unit 21, a media control protocol execution unit 22, a media distribution protocol execution unit 23, and a media storage unit 24.

  The session control protocol execution unit 21 establishes, changes, and disconnects a session of a protocol to be controlled by executing a session control protocol represented by SIP. In the video distribution service, there are a media control protocol represented by RTSP and a media distribution protocol represented by RTP as protocols to be controlled by the session control protocol.

  Quality is set for the established session, and communication is performed with the set quality on the session. As items of quality set in the session, there are priority and reserved bandwidth. Their quality settings can be changed.

  In the media control protocol, it is assumed that responsiveness such as playback start and stop depends on the priority setting. In the media distribution protocol, it is assumed that the reproduction quality of video depends on the setting of the reserved bandwidth.

  When establishing a session, the session control protocol execution unit 21 determines a session identifier for specifying a session of the media control protocol in cooperation with the receiver 11. Further, the session control protocol executing unit 21 may perform control for appropriately setting the quality of the session of the media control protocol in cooperation with the receiver 11 by specifying the media control protocol using the determined session identifier.

  The media control protocol execution unit 22 executes media control protocol to perform media control such as playback and stop of video in cooperation with the receiver 11. The media control protocol performs communication with the receiver 11 for media control with the quality set by the session control protocol.

  The media distribution protocol execution unit 23 distributes the video data stored in the media storage unit 24 to the receiver 11 according to the media control by the media control protocol execution unit 22 by executing the media distribution protocol. The media distribution protocol performs these media distributions with the quality set by the session control protocol.

  The media storage unit 24 stores video data to be distributed to the receiver 11.

  FIG. 4 is a block diagram showing the configuration of the receiver according to the present embodiment. Referring to FIG. 4, the receiver 11 includes a session control protocol execution unit 31, a media control protocol execution unit 32, and a media distribution protocol execution unit 33. In this example, it is assumed that the receiver 11 includes the operation unit 34, the storage unit 35, and the reproduction unit 36 itself. However, one or more of the operation unit 34, the storage unit 35, and the reproduction unit 36 may be provided in a device separate from the receiver 11.

  The session control protocol execution unit 31 establishes, changes, and disconnects a session of the media control protocol for the video distribution service and the media distribution protocol by executing the session control protocol. Quality is set for the established session.

  When establishing a session, the session control protocol execution unit 31 determines a session identifier for specifying a session of the media control protocol in cooperation with the distribution server 12. Further, the session control protocol execution unit 31 may perform control for appropriately setting the quality of the session of the media control protocol in cooperation with the distribution server 12 by specifying the media control protocol using the determined session identifier.

  The media control protocol execution unit 32 performs media control such as playback and stop of video in cooperation with the distribution server 12 by executing the media control protocol. The reproduction or stop of the video by the media control protocol execution unit 32 is performed according to the operation of the operation unit 34 by the user. The media control protocol performs communication with the distribution server 12 for media control with the quality set by the session control protocol.

  The media distribution protocol execution unit 33 receives the video data distributed from the distribution server 12 according to the media control by the media control protocol execution unit 22 by executing the media distribution protocol. The received data is once recorded in the storage unit 35 and then reproduced by the reproduction unit 36. The media distribution protocol performs these media distributions with the quality set by the session control protocol.

  The operation unit 34 receives an operation by the user and transmits the operation content to each unit. For example, session establishment or disconnection by the session control protocol execution unit 31 may be activated by a user operation. Further, the start and stop of video reproduction by the media control protocol execution unit 32 may be activated by a user operation.

  The storage unit 35 stores video data received by the media distribution protocol execution unit 33. The playback unit 36 plays back video data recorded in the storage unit 35.

  As described above, according to the present embodiment, when a session is established by the session control protocol, the session identifier for specifying the session of the media control protocol is determined. Therefore, before the media control protocol itself starts, Therefore, session quality control of the media control protocol becomes possible, and appropriate quality can be ensured from the start. In addition, since it is not necessary to add special processing and functions to the quality assurance network 13 to realize this embodiment, a general quality assurance network can be used as it is in this embodiment.

  In the present embodiment, when the session control protocol establishes a session, a session identifier for specifying the session of the media control protocol is determined. At this time, the session identifier may be determined by exchanging session information including the session identifier between the distribution server 12 and the receiver 11. For example, the distribution server 12 may determine the session identifier and notify the receiver 11 of it. Further, the receiver 11 may determine the session identifier and notify the distribution server 12 of it. Or you may decide to select the session identifier which can be used in both, while the delivery server 12 and the receiver 11 mutually confirm. Further, the determined session identifier of the media control protocol is one of the distribution server 11, the receiver 12, and the session control server (not shown) in the quality assurance network 13 while the media control protocol is maintained. May be managed by one, or a plurality of them, or all of them may be managed individually.

  In the present embodiment, the distribution server 12 and the receiver 11 determine session information necessary for media control when determining the session identifier, and determine session information at the start of the media control protocol. May be omitted. The procedure at the start of the video distribution service can be simplified.

  In general, the media control protocol shifts from an initial state to a standby state, thereby enabling a video reproduction or the like. For example, in RTSP, the four states of “Initial”, “Ready”, “Playing”, and “Recording” are changed in response to a media control operation. When the media control shifts to the “Ready” state through the “Initial” state, the video can be reproduced.

  However, if the session identifier and other session information are determined when the session is established as described above, the media control protocol does not pass through the initial state and the video control is triggered when the session control protocol establishes the session. You may decide to be in a standby state where reproduction or the like is possible. For example, in RTSP, the video playback may be enabled by shifting to the “Ready” state without going through the “Initial” state.

  Further, in this case, the media control protocol may not have a state of an initial state, and may be terminated by releasing the state management without passing through the initial state when the session control protocol disconnects the session.

  In the present embodiment, since the media distribution protocol can specify a session by a pair of a source / destination IP address and a source / destination port number, the session control protocol is a session identifier of the media control protocol when a session is established. Only the media distribution protocol session identifier is not determined. However, the present invention is not limited to this. As another example, the session control protocol may determine both the session identifier of the media control protocol and the session identifier of the media distribution protocol when the session is established. Then, even when a dynamically selected port is used instead of the default port for the media distribution protocol, session control of the media distribution protocol such as securing a band for media distribution can be performed immediately after the session is established. .

  In the present embodiment, an example in which the video distribution service is realized by the media control protocol and the media distribution protocol is shown. However, the present invention is not limited to this. As another example, one or both of an error correction protocol and a QoS report protocol may be further used to realize a video distribution service. In this case, the session control protocol also controls the error correction protocol session and the QoS report protocol session. Therefore, the session control protocol may also determine the session identifiers of one or both of the error correction protocol and the QoS report protocol at the time of session establishment.

  Moreover, in this embodiment, the example which assumed that the delivery server 12 was physically comprised by one apparatus was shown. However, the present invention is not limited to this. As another example, the distribution server 12 may have a configuration in which the session control protocol execution unit 21, the media control protocol execution unit 22, and the media distribution protocol execution unit 23 are distributed and arranged in a plurality of devices.

  Moreover, in this embodiment, the example which assumed that the receiver 11 was physically comprised by one apparatus was shown. However, the present invention is not limited to this. As another example, the receiver 11 may have a configuration in which a session control protocol execution unit 31, a media control protocol execution unit 32, and a media distribution protocol execution unit 33 are distributed and arranged in a plurality of devices. Similarly, the distribution server 12 may have a configuration in which the session control protocol execution unit 21, the media control protocol execution unit 22, and the media distribution protocol execution unit 23 are distributed and arranged in a plurality of devices.

Moreover, although the example which assumed the unicast video delivery was shown in this embodiment, this invention is not limited to this. Even when a video is distributed from one distribution server 12 to a plurality of receivers 11 by multicast, the session identifier may be determined at the time of session establishment.
(First embodiment)
In the first embodiment, SIP is used as the session control protocol, RTSP is used as the media control protocol, and RTP is used as the media distribution protocol. In the first embodiment, it is assumed that the distribution server 12 determines the session identifier of the media control protocol.

  FIG. 5 is a sequence diagram showing the operation of the communication system in the first embodiment. Referring to FIG. 5, when the receiver 11 sends a “SIP INVITE” message requesting establishment of a session to the quality assurance network 13 (step 201), the quality assurance network 13 sends “SIP An INVITE "message is sent (step 202).

  The distribution server 12 that has received the “SIP INVITE” message returns a “SIP 200 OK” message indicating acceptance of the session start request to the quality assurance network 13 (step 203). In this embodiment, the distribution server 12 determines the RTSP session identifier as described above. The RTSP session identifier (session ID in the figure) determined by the distribution server 12 is inserted into the SIP-SDP (Session Description Protocol) of this “SIP 200 OK” message.

  The quality assurance network 13 that has received the “SIP 200 OK” message transmits a “SIP 200 OK” message to the receiver 11 (step 204). In this embodiment, the session information including the session identifier of the media control protocol is also inserted into the SIP-SDP of this “SIP 200 OK” message. By doing so, the receiver 11 can also specify the session of the media control protocol. However, if it is not necessary for the receiver 11 to specify a media control protocol session for session control, the session identifier of the media control protocol is inserted in the “SIP 200 OK” message from the quality assurance network 13 to the receiver 11. It does not have to be.

  Receiving the “SIP 200 OK” message, the receiver 11 sends a “SIP ACK” message indicating that the establishment of the session has been confirmed to the quality assurance network 13 (step 205). A "SIP ACK" message is sent to 12 (step 206).

  In this embodiment, it is assumed that session information including an RTSP session identifier is inserted into the “SIP 200 OK” message in step 203. Also, it is assumed that an RTSP session is started by inserting session information into the SIP-SDP. As a result, since an appropriate bandwidth is secured for this session and an appropriate priority is set, the SETUP and DESCRIBE procedures are omitted in RTSP (step 207).

  If the RTSP SETUP or DESCRIBE is omitted, the “Ready” state in which the video can be immediately reproduced is obtained. In the example of FIG. 5, the receiver 11 sends a “RTSP PLAY” message to the distribution server 12 to send a video playback request (step 208). Upon receiving the “RTSP PLAY” message, the distribution server 12 returns an “RTSP 200 OK” message indicating acceptance of the request to the receiver 11 (step 209), and distributes the video data to the receiver 11 by RTP (step 209). Step 201). Receiving the video data, the receiver 11 temporarily stores the video data in the storage unit 35 and then plays it back by the playback unit 36.

  In this embodiment, it is assumed that the session is released from the “Ready” state without going through the “Initial” state. Therefore, the RTSP-TEARDOWN procedure is omitted (step 211). However, the present invention is not limited to this, and the session may be released from the “Ready” state through the “Initial” state according to a general state transition.

  When the receiver 11 sends a “SIP BYE” message requesting session disconnection to the quality assurance network 13 (step 212), a “SIP BYE” message is sent from the quality assurance network 13 to the distribution server 12. (Step 213).

The distribution server 12 that has received the “SIP BYE” message sends a “SIP 200 OK” message indicating acceptance of the session disconnection request to the quality assurance network 13 (step 214), and receives it from the quality assurance network 13. The “SIP 200 OK” message is also sent to the machine 11 (step 215). As a result, the session is disconnected and communication ends.
(Second embodiment)
In the second embodiment, as in the first embodiment, SIP is used as the session control protocol, RTSP is used as the media control protocol, and RTP is used as the media distribution protocol. However, in the second embodiment, unlike the first embodiment, the receiver 11 determines the session identifier of the media control protocol.

  FIG. 6 is a sequence diagram showing the operation of the communication system in the second embodiment. In the second embodiment, as in the first embodiment, the receiver 11 sends a “SIP INVITE” message requesting establishment of a session to the quality assurance network 13 (step 301). However, in the first embodiment shown in FIG. 5, the session information including the session identifier (session ID) of the media control protocol inserted in the “SIP 200 OK” message in step 203 is “SIP Inserted in the "INVITE" message.

  Subsequently, a “SIP INVITE” message is sent from the quality assurance network 13 to the distribution server 12 (step 302). In this embodiment, the session information including the session identifier of the media control protocol is also inserted into the SIP-SDP of this “SIP INVITE” message. By doing so, the distribution server 12 can also specify the session of the media control protocol.

The distribution server 12 that has received the “SIP INVITE” message returns a “SIP 200 OK” message indicating acceptance of the session start request to the quality assurance network 13 (step 303). In this embodiment, the session identifier of the media control protocol does not have to be inserted into this “SIP 200 OK” message. The quality assurance network 13 that has received the “SIP 200 OK” message transmits the “SIP 200 OK” message to the receiver 11 (step 304). The subsequent steps are the same as those in the first embodiment shown in FIG. 5 (steps 205 to 215).
(Third embodiment)
In the third embodiment, as in the first embodiment, SIP is used as the session control protocol, RTSP is used as the media control protocol, and RTP is used as the media distribution protocol. In the third embodiment, the distribution server 12 determines the session identifier of the media control protocol as in the first embodiment. However, in the third embodiment, unlike the second embodiment, the session information including the session identifier of the media control protocol is notified by the “SIP 183 session progress” message.

  FIG. 7 is a sequence diagram showing the operation of the communication system in the third embodiment. When the receiver 11 sends a “SIP INVITE” message requesting establishment of a session to the quality assurance network 13 (step 201), a “SIP INVITE” message is sent from the quality assurance network 13 to the distribution server 12. (Step 202).

  The distribution server 12 that has received the “SIP INVITE” message transmits a “SIP 183 session progress” message to the quality assurance network 13 as a provisional response (step 401). Session information including the session identifier of the media control protocol determined by the distribution server 12 is inserted into the SIP-SDP of the “SIP 183 session progress” message. Thereby, the session information of the media control protocol is notified to the quality assurance network 13.

  The quality assurance network 13 that has received the “SIP 183 session progress” message transmits the “SIP 183 session progress” message to the receiver 11 (step 402).

  Receiving the “SIP 183 session progress” message, the receiver 11 returns a “SIP PRACK” message indicating that the provisional response has been confirmed to the quality assurance network 13 (step 403). The quality assurance network 13 that has received the “SIP PRACK” message transmits the “SIP PRACK” message to the distribution server 12 (step 404).

The distribution server 12 that has received the “SIP PRACK” message returns a “SIP 200 OK” message indicating that the session start request is finally accepted to the quality assurance network 13 (step 405). The quality assurance network 13 that has received the “SIP 200 OK” message transmits the “SIP 200 OK” message to the receiver 11 (step 406). The subsequent steps are the same as those in the first embodiment shown in FIG. 5 (steps 205 to 215).
(Fourth embodiment)
In the fourth embodiment, as in the first embodiment, SIP is used as the session control protocol, RTSP is used as the media control protocol, and RTP is used as the media distribution protocol. In the fourth embodiment, similarly to the second embodiment, the receiver 11 determines the session identifier of the media control protocol. In the fourth embodiment, as in the third embodiment, a “SIP 183 session progress” message is sent from the distribution server 12, but session information including the session identifier of the media control protocol is not inserted therein. In the fourth embodiment, the session information including the session identifier of the media control protocol is inserted into the “SIP PRACK” message indicating confirmation for the “SIP 183 session progress” message.

  FIG. 8 is a sequence diagram showing the operation of the communication system in the fourth embodiment. The distribution server 12 that has received the “SIP INVITE” message transmits a “SIP 183 session progress” message to the quality assurance network 13 as a provisional response (step 501). The quality assurance network 13 that has received the “SIP 183 session progress” message transmits a “SIP 183 session progress” message to the receiver 11 (step 502).

Receiving the “SIP 183 session progress” message, the receiver 11 returns a “SIP PRACK” message indicating that the provisional response has been confirmed to the quality assurance network 13 (step 503). Session information including the session identifier of the media control protocol is inserted into the “SIP PRACK” message. The quality assurance network 13 that has received the “SIP PRACK” message transmits a “SIP PRACK” message to the distribution server 12 (step 504). The subsequent steps are the same as those of the third embodiment shown in FIG. 7 (steps 405 to 406 and 205 to 215).
(Fifth embodiment)
In the fifth embodiment, as in the first embodiment, SIP is used as the session control protocol, RTSP is used as the media control protocol, and RTP is used as the media distribution protocol. In the fifth embodiment, the distribution server 12 communicates with the receiver 11 by SIP, and confirms that both the distribution server 12 and the receiver 11 are acceptable. The session identifier shall be determined.

  FIG. 9 is a sequence diagram showing the operation of the communication system in the fifth embodiment. The distribution server 12 that has received the “SIP INVITE” message from the quality assurance network 13 transmits a “SIP 183 session progress” message to the quality assurance network 13 (step 601). In this message, the session identifier of the media control protocol selected by the distribution server 12 is inserted. The quality assurance network 13 that has received the “SIP 183 session progress” message transmits a “SIP 183 session progress” message in which the session identifier of the media control protocol is inserted to the receiver 11 (step 602).

  Thereafter, the receiver 11 notifies the distribution server 12 whether or not the candidate for the session identifier selected by the distribution server 12 can be accepted, and updates the session identifier as necessary (steps 603 to 610). Under the agreement of both the receiver 11 and the distribution server 12, the session identifier of the media control protocol is determined, and the distribution server 611 extracts video data (steps 611 to 616).

  When video data is taken out by the distribution server 12, session establishment is completed with a response from the distribution server 12 (steps 617 to 620). Thereafter, the process is the same as that of the first embodiment shown in FIG. 5 (steps 207 to 215).

  In this embodiment, it is determined whether or not the receiver 11 can accept the session identifier selected by the distribution server 12, and the determination result is notified to the distribution server 12. However, the present invention is not limited to this. It is not limited. In addition, the session identifier actually used may be determined while the distribution server 12 and the receiver 11 notify each other of acceptable session identifiers.

Further, in the present embodiment, an example is shown in which the distribution server 12 notifies the receiver 11 of the video data being extracted by the “SIP 180 Ringing” message. However, the present invention is not limited to this, and the “SIP 180 Ringing” message in steps 713 and 714 may be omitted.
(Sixth embodiment)
In the sixth example, contrary to the fifth embodiment, the receiver 11 communicates with the distribution server 12 by SIP and confirms that both the distribution server 12 and the receiver 11 are acceptable. Let us determine the final session identifier of the media control protocol.

  FIG. 10 is a sequence diagram showing the operation of the communication system in the sixth embodiment. The receiver 11 transmits a “SIP INVITE” message in which the session information including the session identifier of the media control protocol selected by the receiver 11 is inserted to the quality assurance network 13 (step 701). The quality assurance network 13 that has received the “SIP INVITE” message transmits the “SIP INVITE” message in which the session information including the session identifier is inserted to the distribution server 12 (step 702).

  Thereafter, the distribution server 12 notifies the receiver 11 whether or not the candidate for the session identifier selected by the receiver 11 can be accepted, and updates the session identifier as necessary (steps 703 to 712). Under the agreement of both the receiver 11 and the distribution server 12, the session identifier of the media control protocol is determined, and the distribution server 611 extracts video data (steps 713 to 716).

  When the video data is taken out by the distribution server 12, the establishment of the session is completed in response to a response from the distribution server 12 (steps 719 to 722). Thereafter, the process is the same as that of the first embodiment shown in FIG. 5 (steps 207 to 215).

  Note that the receiver 11 in the above-described embodiment or each example causes a computer to execute a software program that defines the operations of the session control protocol execution unit 21, the media control protocol execution unit 22, and the media distribution protocol execution unit 23. Can also be realized.

In addition, the distribution server 12 in the above-described embodiment or each example also causes a computer to execute a software program that defines the operations of the session control protocol execution unit 31, the media control protocol execution unit 32, and the media distribution protocol execution unit 33. Can also be realized.
(Appendix)
(Appendix 1)
A communication system for transferring data between first and second communication devices via a quality assurance network capable of setting quality in session units,
The first communication device is:
First session control protocol execution for executing a session control protocol and establishing a first session for a media control protocol used for data distribution control and a second session for a media distribution protocol used for data distribution And
After the first and second sessions are established by the session control protocol execution unit, the data transfer is performed on the first and second sessions by executing the media control protocol and the media distribution protocol. A first media control protocol execution unit and a first media distribution protocol execution unit for performing communication related to
The second communication device is:
A second session control protocol execution unit that executes the session control protocol, communicates with the first session control protocol execution unit, and establishes the first and second sessions with the first communication device;
After the first and second sessions are established, a second medium that performs communication related to the transfer of the data on the first and second sessions by executing the media distribution protocol and the media control protocol A control protocol execution unit and a second media distribution protocol execution unit,
When establishing the first session, the first and second session control protocol execution units determine a session identifier for identifying the first session, and transmits the session identifier to the quality assurance network.
The communication system, wherein the first and second media control protocol execution units perform communication on a first session uniquely specified by a session identifier determined by the first and second session control protocol execution units.
(Appendix 2)
The communication system according to appendix 1, wherein the quality assurance network transmits the session identifier received from the first communication device to the second communication device.
(Appendix 3)
The first communication device is a distribution server, and the second communication device is a reception device;
The communication system according to appendix 1 or 2, wherein when the receiving device requests the distribution server to establish a session, the first session control protocol execution unit determines a session identifier.
(Appendix 4)
The first communication device is a receiving device, the second communication device is a distribution server,
The communication system according to appendix 1 or 2, wherein the first session control protocol executing unit determines a session identifier when the receiving device requests the distribution server to establish a session.
(Appendix 5)
The session control protocol is a Session Initiation Protocol, the media distribution protocol is a Real Time Transport Protocol, the media control protocol is a Real Time Streaming Protocol, and the Real Time Streaming Protocol is set on the Transport implementation. The communication system according to any one of appendices 1 to 4.
(Appendix 6)
The first communication device and the second communication device transmit and receive session information including the session identifier by executing the session control protocol, and immediately execute a distribution start request for the state of the media control protocol. The communication system according to any one of appendices 1 to 5, wherein the communication system is in a state in which it is possible.
(Appendix 7)
Either one of the first communication device and the second communication device is a distribution server that distributes the data, and the other is a receiver that receives the data from the distribution server,
The delivery server and the receiver deliver the data from the delivery server to the receiver by performing communication of the media control protocol related to the transfer of the data on the session,
The communication system according to any one of appendices 1 to 6, wherein the data is distributed from the distribution server to the plurality of receivers by multicast.
(Appendix 8)
The first communication device and the second communication device communicate with the media control protocol when the session identifier is determined and the session can be controlled by specifying the media control protocol. The communication system according to any one of appendices 1 to 7, wherein a quality of a session of at least one of the media control protocol and the media distribution protocol is set before starting.
(Appendix 9)
While a session for at least one of the media control protocol and the media distribution protocol is maintained, the session identifier of the session is set to the first communication device, the second communication device, or the quality assurance network. The communication system according to any one of appendices 1 to 8, managed by any one, a plurality, or all of them.
(Appendix 10)
At least one of the first communication device and the second communication device is composed of one or a plurality of devices, and the session control protocol, the media control protocol, and the media distribution protocol are set to the one or more devices. The communication system according to any one of appendices 1 to 9, which is executed by the apparatus.
(Appendix 11)
The first communication device confirms that both the first communication device and the second communication device are acceptable by communicating with the second communication device using the session control protocol. 11. The communication system according to any one of appendices 1 to 10, wherein a final session identifier is determined after that.
(Appendix 12)
A communication method for transferring data between first and second communication devices via a quality assurance network capable of setting quality in session units,
The first communication device is:
First session control protocol execution for executing a session control protocol and establishing a first session for a media control protocol used for data distribution control and a second session for a media distribution protocol used for data distribution And
After the first and second sessions are established by the session control protocol execution unit, the data transfer is performed on the first and second sessions by executing the media control protocol and the media distribution protocol. A first media control protocol execution unit and a first media distribution protocol execution unit for performing communication related to
The second communication device is:
A second session control protocol execution unit that executes the session control protocol, communicates with the first session control protocol execution unit, and establishes the first and second sessions with the first communication device;
After the first and second sessions are established, a second medium that performs communication related to the transfer of the data on the first and second sessions by executing the media distribution protocol and the media control protocol A control protocol execution unit and a second media distribution protocol execution unit,
The first and second session control protocol execution units,
When establishing the first session, a session identifier for identifying the first session is determined and transmitted to the quality assurance network;
The first and second media control protocol execution units,
A communication method for performing communication on a first session uniquely specified by a session identifier determined by the first and second session control protocol execution units.
(Appendix 13)
A communication device that transfers data via a quality assurance network in which quality can be set on a session basis,
A session control protocol execution unit that executes a session control protocol and establishes a first session for a media control protocol used for distribution control of the data and a second session for a media distribution protocol used for distribution of the data; ,
After the first and second sessions are established by the session control protocol execution unit, the data transfer is performed on the first and second sessions by executing the media control protocol and the media distribution protocol. A media control protocol execution unit and a media distribution protocol execution unit that perform communication related to
The session control protocol execution unit includes:
When establishing the first session, a session identifier for identifying the first session is determined and transmitted to the quality assurance network;
The media control protocol execution unit,
A communication apparatus that performs communication on a first session uniquely specified by a session identifier determined by the session control protocol execution unit.
(Appendix 14)
A program for causing a computer to execute a process of transferring data via a quality assurance network in which quality can be set on a session basis,
Session control protocol execution processing for executing a session control protocol and establishing a first session for a media control protocol used for distribution control of the data and a second session for a media distribution protocol used for distribution of the data; ,
After the first and second sessions are established by the session control protocol execution process, the media control protocol and the media distribution protocol are executed, thereby transferring the data on the first and second sessions. Including media control protocol execution processing and media distribution protocol execution processing for communication,
In the session control protocol execution process,
When establishing the first session, a session identifier for identifying the first session is determined and transmitted to the quality assurance network.
In the media control protocol execution process,
A program for causing a computer to execute a process for performing communication on a first session uniquely specified by a session identifier determined by the session control protocol process.

DESCRIPTION OF SYMBOLS 11 Distribution server 12 Receiver 13 Quality assurance network 21 Session control protocol execution part 22 Media control protocol execution part 23 Media distribution protocol execution part 24 Media storage part 31 Session control protocol execution part 32 Media control protocol execution part 33 Media distribution protocol execution Unit 34 operation unit 35 storage unit 36 playback unit

Claims (2)

A session control protocol execution unit for executing a session control protocol and establishing a session for executing a media control protocol used for data distribution control;
After the session is established by the session control protocol execution unit, a media control protocol execution unit that performs communication related to distribution control of the data on the session by executing the media control protocol,
The session control protocol execution unit, when establishing the session, determines a session identifier for identifying the session, and transmits to the network,
The media control protocol execution unit performs communication on a session specified by the determined session identifier. Executing a session control protocol and establishing a session for executing a media control protocol used for data distribution control;
Performing communication related to data distribution control on the session by executing the media control protocol after the session is established in the step of establishing the session, and
In the step of establishing the session, when establishing the session, a session identifier for identifying the session is determined and transmitted to the network;
A communication method for performing communication on a session specified by the determined session identifier.

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