JP6479701B2 - Early media authorization control system and early media authorization control method - Google Patents

Description

  The present invention relates to an early media authorization control system and an early media authorization control method, and more particularly to a session control and media packet processing technique using SIP (Session Initiation Protocol).

  In the audio / video communication using SIP, the multimedia information used by the calling terminal and the called terminal, that is, the codec, the transmission / reception IP address / port number, etc., is defined as an SDP (Session Description Protocol) defined in RFC4566. The media conditions to be used at the arrival / departure terminal are determined by describing and negotiating with each other. This RFC4566 is defined by IETF (The Internet Engineering Task Force). After establishing the communication path (session) in this way, actual media communication, that is, transmission / reception of RTP (Real-time Transport Protocol) packets is started.

  Even in the state before the SIP session is established, it is necessary to transmit / receive media such as pre-call guidance, that is, “the phone number you have called is not currently used”. Such media is called “early media”. The state before the SIP session is established is an “early-state” state, which means that “200 OK” is not received for the “INVITE request”.

  In the SIP session, the early media connection path includes five pieces of information: a transmission / reception IP address, a transmission / reception port number, and a transport protocol. As a SIP extension for controlling the opening / closing of such an early media connection path, Non-Patent Document 1 defines a “P (Private) -Early-Media” header. FIG. 9 shows an example of the operation procedure in early media control using the “P-Early-Media header”.

  In FIG. 9, the UAC (User Agent Client) 71a of the calling terminal 71, the proxy 72a on the network 72, and the UAS (User Agent Server) 73a of the called terminal 73 are a CPU ( The Central Processing Unit) is implemented by executing a software program that mounts the SIP stack. Also, the media processing unit 71b of the calling terminal 71, the media processing unit 72b of the network 72, and the media processing unit 73b of the destination terminal 73 shown in FIG. 9 are elements that process RTP packets as media.

A communication procedure of the system shown in FIG. 9 will be described below.
(1): The UAC (User Agent Client) 71a of the calling terminal 71 that supports the P-Early-Media header assigns “P-Early-Media: supported” to the “INVITE request” and sends it to the subsequent node using RFC5009. Indicates that a set of defined processing sets has been implemented.

(2): The proxy 72a on the network 72 that supports the P-Early-Media header determines whether the source / destination of the SIP message is a trust domain (defined in RFC 3324) with respect to the P-Early-Media header. to decide. That is, the proxy 72a determines whether the node supports a series of processing sets defined in RFC5009 as a specific specification of Spec (T).
(2-1): Further, when both the transmission source and the destination are in the trust domain, the P-Early-Media header is transferred.
(2-2): In cases other than (2-1) above, the P-Early-Media header is not transferred to the succeeding node.

  (3): The UAS (User Agent Server) 73a of the destination terminal 73 supporting the P-Early-Media header indicates the direction of the early media requesting authorization “18x” (where “x” is optional) in response Specify in the P-Early-Media header. FIG. 8 shows an example of requesting authorization of early media in the direction from the UAS 73a to the UAC 71a. In this case, “sendonly” is designated as the header value.

  (4): The Proxy performs a media path opening process in the direction from the UAS 73a to the UAC 71a based on the setting value (sendonly) of P-Early-Media, and transfers an “18x” response. At this stage, the media in the direction from the UAS 73a to the UAC 71a is in a blocked state.

  (5): When receiving “P-Early-Media: sendonly”, the UAC 71a recognizes that the authorization of the early media in the direction from the UAS 73a toward itself is required, and plays the early media from the UAS 73a side Judge whether to do. When authorizing, the UAC 71a issues a media playback instruction to the media processing unit 71b and transmits a “PRACK request”.

(6): The Proxy 72a transfers a “PRACK request”.
(7): Upon receiving the “PRACK request”, the UAS 73a starts early media transmission to the calling party.
(8): The UAC 71a reproduces early media transmitted from the UAS 73a side.

R. Ejzak, Alcatel-Lucent, "Private Header (P-Header) Extension to the Session Initiation Protocol (SIP) for Authorization of Early Media", IETF RFC 5009, September 2007.

  When communicating between a calling terminal and a called terminal, the calling terminal and the called terminal may be connected to networks provided by different communication carriers. Therefore, in a state where the network of the calling terminal and the network of the called terminal are mutually connected, the calling terminal establishes a session (communication path) with the called terminal and starts communication.

  10A and 10B show configuration examples of systems in which networks provided by different telecommunications carriers are connected to each other. In the system 100A of FIG. 10A and the system 100B of FIG. 10B, the calling network 82 to which the calling terminal 81 belongs receives “200 OK” for the outgoing call after establishing the session. It is assumed that charging for communication is started at this timing. On the other hand, the destination network 83 to which the destination terminal 84 belongs is provided by a communication carrier different from the source network 82.

  Therefore, in the system 100A shown in FIG. 10 (a) and the system 100B shown in FIG. 10 (b), the equipment belonging to the originating network 82 does not respond to early media such as advance guidance transmitted before session establishment. Do not charge. There is no problem when the early media is sent from the media server 83a or the like of the destination network 83 as in the system 100A shown in FIG.

  On the other hand, as in the system 100B shown in FIG. 10B, the destination terminal 84 may attempt to transmit the call before the establishment of the call as an early medium to the source terminal 81 via the destination network 83 and the source network 82. Sex is conceivable. In this case, since the facility of the originating network 82 does not charge for the early media transmitted before the session is established, it is possible to make a call free of charge even for a call intended for the facility of the originating network 82. There is sex.

  For carriers that start charging after call establishment, the early media generated as advance guidance for network services, regardless of whether they belong to their own network or other companies, must be provided to users free of charge (non-charging) Is considered desirable. That is, like the system 100A shown in FIG. 10A, it is desirable to allow early communication of early guidance and to provide the user free of charge (non-billing). However, as in the system 100B shown in FIG. 10B, it is desirable to prevent free calls between calling terminals due to transmission / reception of early media between users.

  However, when a plurality of networks different from each other are interconnected, and a network of a business that does not allow early media between users and a network of a business that permits early media between users are connected and communicated, 10 (a) and 10 (b) were unable to switch the appropriate control for early media.

  That is, in order to perform the control in FIGS. 10A and 10B, a state where “the destination terminal 84 is about to send the early media” and “ The state where the guidance device of the network 83 is about to send out early media needs to be identified from the information element in the “18x” response. However, the current 3GPP / IETF international standard specification cannot perform this identification.

  FIG. 11 shows an operation example of a system in which a plurality of networks with different operators are interconnected. In the operation example shown in FIG. 11, in the third procedure (3), SDP (# 1) is transmitted as “183 Session Progress” from the destination terminal 93 to the destination network 92, and the fourth procedure (4). Then, SDP (# 2) is transmitted as “183 Session Progress” from destination network 92 to source network 91. Here, in each SDP (# 1, # 2), as shown in FIG. 11, the SDP creator information ("o = ... line"), the media receiving address ("c = ..."). .. "line) and port number (" m = ... "line) are described respectively.

  However, especially in the situation where networks of different operators are interconnected, NAPT (Network Address Port Translation) / Codec conversion is generally performed by SBC (Session Border Controller, Gateway device) installed in the middle of the SIP route. Then, the contents of the SDP are rewritten. In the example shown in FIG. 11, it is assumed that the destination network 92 side performs NAPT and rewrites SDP.

  As a result, in the example shown in FIG. 11, the transmission source that can be recognized from the SDP (# 2) information received on the source network 91 side, that is, the address and port number of the media processing unit MP2 in the destination network 92, and the actual early The address and port of the destination terminal 93 included in the SDP (# 1) transmitted by the media processing unit MP1 of the destination terminal 93, which is the media transmission source, do not match. Therefore, even if SDP (# 2) is referred to for the control shown in FIGS. 10A and 10B, the media processing unit MP1 that is the transmission source of the early media cannot be correctly identified.

  The present invention has been made in view of the above situation, and when connecting an operator network that allows user-to-user early media and an operator network that does not allow user-to-user early media, An object of the present invention is to provide an early media authorization control system and an early media authorization control method capable of communicating early media such as free prior guidance from the destination network while preventing early media from the destination terminal. .

The above object of the present invention can be achieved by the following configurations.
(1) An early media authorization control device for controlling communication of early media, and an early media trying to transmit early media, which are used for connection between different network of different service providers of the originating network and the service provider of the terminating network An early media authorization control system comprising a media generation source device,
In the negotiation process before session establishment using the session establishment protocol, the early media generation source apparatus includes the early media generation source information included in the SIP message of the session establishment protocol and transmits it to the early media authorization control apparatus. / SDP processing unit
The early media authorization control device itself holds generation source reference information that can be used to identify approval / disapproval for the early media generation source information, and receives the received early media generation source information and the generation source reference information. And a second SIP / SDP processing unit for identifying communication of the early media.
It is characterized by that.

  According to the early media authorization control system of (1) above, the SIP / SDP processing unit of the early media generation source device includes appropriate early media generation source information in a SIP message and transmits the SIP message to the early media authorization control device. be able to. Thus, the early media authorization control device that receives this SIP message correctly recognizes the actual source of the early media even in a situation where a plurality of different service provider networks are connected to each other. It is possible to communicate early media such as free advance guidance from the destination network while preventing early media from the destination terminal.

(2) The early media generation source device further includes a media processing unit that opens or closes the path of the early media in response to a path opening instruction from the first SIP / SDP processing unit,
The early media authorization control device further includes a media processing unit that opens or closes the path of the early media in response to a path opening instruction from the second SIP / SDP processing unit.
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (2) above, an early media path is appropriately determined by the functions of the media processing unit of the early media generation source device and the media processing unit of the early media authorization control device. Can be controlled. That is, it is possible to switch the control so that the early media path transmitted by the user terminal is blocked and the early media path such as the advance guidance generated by the transmission source other than the user terminal is opened.

(3) The early media generation source device generates, as the early media generation source information, information indicating that its own device type is at least one of a provider network device and a user terminal.
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (3) above, in the early media generation source information transmitted from the early media generation source device, its own device type is an operator network device and a user terminal. Information representing at least one of them is included. Therefore, the early media generation source device can easily identify whether or not to permit the opening of the path based on the early media generation source information.

(4) The early media generation source device generates unique identification information for identifying a network to which the device belongs as the early media generation source information.
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (4), the unique identification for specifying the network to which the early media generation source information belongs belongs in the early media generation source information transmitted from the early media generation source device. Contains information. Therefore, the early media generation source device can easily identify whether or not to permit the opening of the path based on the early media generation source information.

(5) The early media generation source device generates unique identification information capable of specifying its own device as the early media generation source information.
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (5) above, unique identification information capable of specifying its own device is included in the early media generation source information transmitted from the early media generation source device. Therefore, the early media generation source device can easily identify whether or not to permit the opening of the path based on the early media generation source information.

(6) The early media generation source device identifies whether or not the early media generation source information is included in the received SIP / SDP message, and the early media generation source included in the received SIP / SDP message. Sending at least one of the information and the early media generation source information pre-assigned to the SIP message included in the SIP message;
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (6), the SIP / SDP message received by the early media generation source device includes the case where the early media generation source information generated at the transmission source of the early media is included. Appropriate responses can be made in any situation where there is no.

(7) The early media generation source device places the early media in a location that is not affected by the rewriting in the SIP / SDP message even when the session information is rewritten in an intermediate node of the call connection path. Send including source information,
The early media authorization control system according to (1) above, wherein

  According to the early media authorization control system of (7) above, a plurality of networks managed by different companies are connected to each other, and the contents of the SDP are executed by executing NAPT (Network Address Port Translation) / codec conversion. Even when the file is rewritten by the intermediate node, it is possible to transmit appropriate early media generation source information.

(8) An early media authorization control device that controls communication of early media, and an early media that attempts to transmit early media, which are used for connection between different vendor networks where the originating network service provider and the terminating network service provider are different An early media authorization control method for controlling a communication system comprising a media generation source device,
In the negotiation process before session establishment using the session establishment protocol, the early media generation source information is included in the SIP message and transmitted from the early media generation source device to the early media authorization control device.
The early media authorization control device compares the early media generation source information received from the early media generation source device with generation source reference information prepared in advance to identify communication of the early media.
An early media authorization control method characterized by the above.

  According to the early media authorization control method of (8) above, appropriate early media creation source information can be included in a SIP message and transmitted from the early media creation source device to the early media authorization control device. Therefore, the early media authorization control apparatus that receives this SIP message can correctly recognize the actual source of early media even in a situation where a plurality of different service provider networks are connected to each other.

  According to the early media authorization control system and the early media authorization control method of the present invention, when connecting an operator network that allows user-to-user early media and an unacceptable operator network, an operator network that does not allow user-to-user early media. On the other hand, it is possible to communicate early media such as free advance guidance from the destination network while preventing early media from the destination terminal.

It is a block diagram which shows the structural example of the early media authorization control system in embodiment of this invention. It is a sequence diagram which shows the "operation | movement 1" of the early media authorization control system of embodiment of this invention. FIG. 11 is a sequence diagram showing “Operation 2”. FIG. 10 is a sequence diagram showing “operation 3” following the “operation 2”. It is a schematic diagram which shows the list of the specific coding examples of early media production | generation source information. It is a block diagram which shows the operation example (1) of the communication system at the time of implementing this invention. It is a block diagram which shows the operation example (2) of the communication system at the time of implementing this invention. It is a sequence diagram which shows the operation example of the communication system containing the early media authorization control system in embodiment of this invention. It is a block diagram which shows the operation | movement procedure of normal early media control by a P-Early-Media header. FIG. 10A and FIG. 10B are block diagrams showing examples of early media communication policies in each of the two types of systems. It is a block diagram which shows the example of the operation | movement procedure in case a destination network rewrites SDP, and a SDP message.

Embodiments of the present invention will be described below with reference to the drawings.
<Configuration of Early Media Authorization Control System>
An example of the configuration of an early media authorization control system in an embodiment of the present invention is shown in FIG.

  The early media authorization control system of the present invention includes an early media authorization control device 10 and an early media generation source device 20 as shown in FIG. The early media authorization control device 10 is installed on a network necessary for communication between the calling terminal 30 and the called terminal, that is, in a facility of a telecommunications carrier that provides a service. The early media authorization control apparatus 10 shown in FIG. 1 includes a proxy 11 and a media processing unit 12.

  The early media generation source device 20 shown in FIG. 1 includes a UAS (User Agent Server) 21 installed in a destination terminal and a media processing unit 22, for example. Therefore, the early media authorization control device 10 and the early media generation source device 20 shown in FIG. 1 can be directly applied to the communication system as shown in FIG. Further, the basic operation of the communication system shown in FIG. 1 is the same as the operation of FIG. 9 already described, and thus the description of this basic operation is omitted.

  However, the proxy 11 shown in FIG. 1 also has a special function necessary for operating as the early media authorization control device 10. The UAS 21 shown in FIG. 1 also has a special function necessary to operate as the early media generation source device 20. Actually, the SIP / SDP processing unit 11a in the proxy 11 performs a special function of the early media authorization control device 10, and the SIP / SDP processing unit 21a in the UAS 21 performs a special function of the early media generation source device 20. Fulfill.

  That is, the early media generation source device 20 includes the early media generation source information in the SIP message of the session establishment protocol to the early media authorization control device 10 in the negotiation process before the session establishment using the session establishment protocol (SIP). It has a SIP / SDP processor 21a for transmission.

  In addition, the early media authorization control apparatus 10 itself holds generation source reference information that can be used to identify approval / disapproval of the early media generation source information, and also receives the received early media generation source information and generation source reference information. And a SIP / SDP processing unit 11a for identifying early media communication.

  Note that a UAC (User Agent Client) 31 of the calling terminal 30, a proxy 11 of the early media authorization control device 10, and a UAS (User Agent Server) 21 of the early media generation source device 20 are, for example, CPU ( The Central Processing Unit) is implemented by executing a software program that mounts the SIP stack. In addition, each media processing unit 12, 22, and 32 shown in FIG. 1 is an element that processes RTP packets as media. The media processing unit 12 opens or closes the early media path according to the path opening instruction from the SIP / SDP processing unit 11a. Similarly, the media processing unit 22 opens or closes an early media path according to a path opening instruction from the SIP / SDP processing unit 21a.

<Details of Early Media Authorization Control System>
By switching the control as in the systems 100A and 100B shown in FIGS. 10A and 10B according to the early media, it is possible to charge appropriately. In order to enable such switching, an intermediate SIP server, that is, the early media authorization control device 10 appropriately determines whether or not to permit early media communication according to the transmission source of the sound source of early media. It needs to be possible.

  As information usable for this determination, early media generation source information Pems is used in the embodiment of the present invention. The early media generation source information Pems is included in the SIP / SDP message and transmitted by the early media generation source device 20 provided in the device that is to transmit the early media. Accordingly, the early media generation source device 20 is installed, for example, in the media server 83a in the system 100A shown in FIG. 10A or the destination terminal 84 in the system 100B shown in FIG. 10B.

As a typical example of the contents of the early media generation source information Pems, it is conceivable to use one or a plurality of information elements (1), (2), and (3) shown below.
(1) Type of device (distinguishing between carrier network device / user terminal, etc.)
(2) Network ID (SIP domain, etc.)
(3) Device ID (FQDN, IP address, etc.)

<Operation of Early Media Authorization Control System>
The operation sequence of the early media authorization control system including the early media authorization control device 10 and the early media generation source device 20 described above is shown in FIG. 2, FIG. 3, and FIG. Note that the operation sequence of FIG. 4 is a continuation of FIG.

<Operation of Early Media Generation Source Device 20>
For example, when the preceding node device 40 illustrated in FIG. 2 attempts to transmit early media, the preceding node device 40 transmits a SIP / SDP message that triggers early media, such as an 18x response including an SDP answer.

  When the SIP / SDP message is received by the SIP / SDP processing unit 21a of the early media generation source device 20 in step S20 of FIG. 2, the SIP / SDP processing unit 21a includes the early media generation source in the received SIP / SDP message. Whether or not the information Pems exists is checked in step S21.

(Case (a))
If the received SIP / SDP message does not include the early media generation source information Pems, the SIP / SDP processing unit 21a generates early media generation source information Pems corresponding to its own device in step S22, and SIP / Write in the SDP message and forward this SIP / SDP message. Note that the contents of the early media generation source information Pems corresponding to the SIP / SDP processing unit 21a itself are determined in advance and stored in the early media generation source device 20.

  Further, the SIP / SDP processing unit 21a performs path establishment control for the media processing unit 22 in step S22. Then, at least the media path in the transmission direction on the transfer destination side of the SIP / SDP message is opened, and the transmission / reception media path on the reception side of the SIP / SDP message is blocked. That is, the SIP / SDP processing unit 21a controls the opening / closing of the media path in each direction as indicated by the four arrows shown in the symbol of the media path state ST1 in FIG. Regarding the directions of these four arrows, the right side represents the transfer source and the left side represents the transfer destination. In step S23, the SIP / SDP processing unit 21a sends the “183 response” including the SDP, the SIP / SDP message that triggers the early media transmission, the early media generation source information, and the SIP / SDP of the early media authorization control device 10. The data is transmitted to the SDP processing unit 11a.

  On the other hand, in FIG. 3, the SIP / SDP processing unit 21a of the early media generation source device 20 receives the early node device 40 that is the generation source in the SIP / SDP message received from the previous node device 40 in step S30. It is assumed that the media generation source information Pems (# 2) is also included. In this case, after step S30, the SIP / SDP processing unit 21a executes the next step S31 or step S33 depending on the case at that time.

(Case (b1))
The SIP / SDP processing unit 21a executes step S31 when generation source information is included in the received SIP / SDP message and priority is given to the early media sent by itself. That is, the SIP / SDP processing unit 21a overwrites the early media generation source information Pems (# 2) included in the received SIP / SDP message with the early media generation source information Pems (# 1) representing itself. Then, the SIP / SDP processing unit 21a performs path opening control for the media processing unit 22 in step S31. In this case, at least the media path in the transmission direction on the transfer destination side of the SIP / SDP message is opened, and the transmission / reception media path on the reception side of the SIP / SDP message is blocked. That is, the SIP / SDP processing unit 21a controls the opening / closing of the media path in each direction as indicated by the four arrows shown in the symbol of the media path state ST2 in FIG. Regarding the directions of these four arrows, the right side represents the transfer source and the left side represents the transfer destination.

  In addition, the SIP / SDP processing unit 21a transmits a SIP / SDP message to the early media authorization control apparatus 10 in step S32. The SIP / SDP message transmitted here includes early media generation source information Pems (# 1) representing the early media generation source device 20 by overwriting in step S31.

(Case (b2))
The SIP / SDP processing unit 21a executes step S33 when generation source information is included in the received SIP / SDP message and priority is given to the early media sent by the preceding node device 40. In this case, the SIP / SDP processing unit 21a performs path opening control for the media processing unit 22. Then, control is performed so that at least a media path from the preceding node device 40 that is the preceding node to the succeeding node can communicate with the early media. That is, the opening / closing of the media path in each direction is controlled as indicated by the four arrows shown in the symbol of the media path state ST3 in FIG. Regarding the directions of these four arrows, the right side represents the transfer source and the left side represents the transfer destination.

  Further, the SIP / SDP processing unit 21a transmits a SIP / SDP message to the early media authorization control apparatus 10 in step S34. The SIP / SDP message transmitted here includes the early media generation source information Pems (# 2) received from the preceding node device 40 in step S30.

  In steps S31 and S33, one of the early media (# 1) sent out by the early media generation source device 20 itself and the early media (# 2) sent out by the preceding node device 40 are preferentially selected. And send the selected early media to the transfer destination. Here, it is necessary to determine the priority order when selecting two early media (# 1, # 2). Such priorities can be easily determined by creating list information representing the priorities of the respective devices in advance and holding them on the early media generation source device 20.

<Operation of Early Media Authorization Control Device 10>
The SIP / SDP processing unit 11a of the early media authorization control device 10 includes the SIP / SDP message (early media generation source information) transmitted by the early media generation source device 20 in step S23 in FIG. 2, step S32 in FIG. 3, or step S34. Step S41 in FIG. 4 is executed.

  In step S41, the SIP / SDP processing unit 11a compares the received early media generation source information Pems with the local policy assigned in advance to the early media authorization control device 10 itself, thereby determining whether or not the corresponding early media can be communicated. Make a decision. For local policies, the list of predefined sources that allow early media communication, i.e., the white list, or the list of predefined sources that reject early media communication, i.e., blacklist information. decide. That is, the communication of the early media can be appropriately identified by collating the received early media generation source information Pems with the information of the white list or the black list. Here, the information of the white list or the black list is generation source reference information that can be used for identification of approval / disapproval for the early media generation source information Pems.

  The SIP / SDP processing unit 11a executes the process of step S42 or S44 of FIG. 4 according to the determination result of step S41, that is, approval / disapproval of communication with the early media.

((A) When communication is authorized)
In step S42, the SIP / SDP processing unit 11a controls the media processing unit 12 to open a media path based on the direction attribute set as the header value of “P-Early-Media”, and in step S43. Forward SIP / SDP messages. If the “P-Early-Media” header is not supported, at least the media path from the side that received the SIP / SDP message is opened.

  That is, the SIP / SDP processing unit 11a controls the opening / closing of the media path in each direction as indicated by the four arrows shown in the symbol of the media path state ST4 in FIG. Regarding the directions of these four arrows, the right side represents the transfer source and the left side represents the transfer destination.

((B) When communication is not authorized)
In step S44, the SIP / SDP processing unit 11a controls the media path from the SIP / SDP message transmission source side to be blocked, and transfers the SIP / SDP message in step S45.

  That is, the opening / closing of the media path in each direction is controlled as indicated by the four arrows shown in the symbol of the media path state ST5 in FIG. Regarding the directions of these four arrows, the right side represents the transfer source and the left side represents the transfer destination.

  2 to 4 show an example in which the “183 response” including the SDP for the “INVITE request” is a SIP / SDP message that triggers early media transmission. However, the present invention can be applied to other cases. For example, according to “PRACK method” defined in “IETF RFC 3262: Reliability of Provisional Responses in SIP” and “UPDATE method” defined in “IETF RFC 3311: The Session Initiation Protocol (SIP) UPDATE Method” The present invention can also be applied to SDP exchange.

<Specific example of early media generation source information Pems>
FIG. 5 shows a list of specific allocation destinations and coding examples of the early media generation source information Pems. FIG. 5 shows five types of specific information allocation examples C1 to C5.

(Information allocation example C1)
The source information setting destination is `` P-Early-Media header '' specified in `` IETF RFC 5009: Private Header (P-Header) Extension to the Session Initiation Protocol (SIP) for Authorization of Early Media ''. New header parameter ". An example of encoding is as follows.
"P-Early-Media: sendrecv; network-privided"

(Information allocation example C2)
The source information is set to “New feature-capability” in the “Feature-Caps header” defined in “IETF RFC 6809: Mechanism to Indicate Support of Features and Capabilities in the Session Initiation Protocol (SIP)”. . An example of encoding is as follows.
"Feature-Caps: *; + early-media = sip: AS@example.co.jp"

(Information allocation example C3)
The generation source information is set to “a = content line new value” in the SDP defined in “IETF RFC 4796: The Session Description Protocol (SDP) Content Attribute”. An example of encoding is as follows.
"A = content: user-provided-early-media"

(Information allocation example C4)
The setting destination of the generation source information is “new SIP header value”. An example of encoding is as follows.
"Early-Media-Origin: AS.example.co.jp"

(Information allocation example C5)
The generation source information is set to “new SDP attribute value”. An example of encoding is as follows.
"A = em-origin: AS.example.co.jp"

  Note that specific allocation destinations and coding examples of the early media generation source information Pems are not limited to the five types shown in FIG. However, in order to enable the early media authorization control apparatus 10 to correctly recognize the early media generation source when a plurality of networks providing different services are connected to each other, the NAPT / codec in the middle of the SIP path Even when the conversion is performed, it is necessary to place it in a place where the contents of the early media generation source information Pems cannot be rewritten. If any one of the five types of information allocation examples C1 to C5 shown in FIG. 5 is used, no problem occurs.

<Operation example when the present invention is applied to an actual communication system>
<When using early media generation source information Pems to avoid free calls>
An operation example (1) and an operation example (2) of the communication system when the present invention is applied to an actual communication system are shown in FIGS. 6 and 7, respectively.

  In the communication system 200A shown in FIG. 6, the calling terminal 51 is connected to the calling network 52, the called terminal 54 is connected to the called network 53A, and the calling network 52 and the called network 53A are connected to each other. Here, it is assumed that the originating network 52 and the terminating network 53A are respectively owned or managed by a plurality of different service providers. Similarly, in the communication system 200B shown in FIG. 7, the calling terminal 51 is connected to the calling network 52, the called terminal 54 is connected to the called network 53B, and the calling network 52 and the called network 53B are connected to each other. . Here, it is assumed that the originating network 52 and the terminating network 53B are respectively owned or managed by a plurality of different service providers.

  6 and 7, the calling network 52 is controlled to start charging when a call is established from the calling terminal 51 (200 OK reception), so the calling network 52 charges the early media. There is nothing. On the other hand, the incoming networks 53A and 53B are controlled so as to allow communication even with early media transmitted and received between users.

  For example, in the communication system 200A of FIG. 6, when the calling terminal 51 makes a call to the called terminal 54, it is impossible for the calling network 52 to know whether the called terminal 54 actually exists. Then, when the called terminal 54 does not exist (when the contract is expired), the server in the called network 53A that manages the called terminal 54 receives the call of the calling terminal 51 as the early media. For example, the voice of the advance guidance such as “the telephone number you have called is not currently used” is transmitted. For such early media, the calling network 52 transfers it to the calling terminal 51 as it is without charging. On the other hand, when the receiving terminal 54 transmits the early media EM1 as the early media before the SIP session is established, if the receiving network 53A and the originating network 52 transfer the early media EM1 to the originating terminal 51 as it is, Since 52 does not charge early media, a free call can be made between the called terminal 54 and the calling terminal 51, and a situation unintended by the operator of the calling network 52 occurs.

  Therefore, the early media authorization control device 10 shown in FIG. 1 is installed in the originating network 52 of FIGS. 6 and 7, and the early media generation source device 20 is installed in the terminating networks 53A and 53B and the terminating terminals in FIGS. Equipped to at least one of 54. As a result, switching of operations as shown in FIGS. 6 and 7 is realized. In the example shown in FIGS. 6 and 7, the “early media generation source information Pems is transmitted by applying the“ information allocation example C5 ”shown in FIG.

As shown in FIG. 6, by calling from the calling terminal 51 to the called terminal 54,
The calling terminal 51 sends an “INVITE request” to the calling network 52 by the procedure (1),
The originating network 52 sends an “INVITE request” to the terminating network 53A according to the procedure (2).
The destination network 53A transmits an “INVITE request” to the destination terminal 54 in the procedure (3).

  The destination terminal 54 transmits “183 response” to the destination network 53A in accordance with the procedure (4) in response to the “INVITE request” received in the procedure (3). The SDP included in the “183 response” includes “a = em-origin: early media generation source information Pems” as “new SDP attribute value” as in “information allocation example C5” illustrated in FIG. UE.example.co.jp "is included. “UE” in this means that “User Equipment”, that is, the transmission source of the early media EM 1 is the user terminal (the destination terminal 54), and is generated by the early media generation source device 20 in the destination terminal 54. The

  As shown in FIG. 6, the destination network 53A transfers the “183 response” including the early media generation source information Pems to the originating network 52 in the procedure (5), and the originating network 52 creates the early media in the procedure (6). The “183 response” including the source information Pems is transferred to the calling terminal 51.

  On the other hand, the early media EM1 transmitted from the destination terminal 54 before the session is established is transferred as it is to the source network 52 side by the destination network 53A. However, the early media authorization control device 10 built in the originating network 52 transmits the early media EM1 by “UE” of the early media generation source information Pem included in the “183 response” received in the procedure of (5). Since it recognizes that the source is the user terminal, the media path of this early media EM1 is blocked and the early media EM1 is not transferred to the calling terminal 51.

  On the other hand, in the case of the communication system 200B shown in FIG. 7, as in the case of FIG. 6, the “INVITE request” is transferred in the steps (1), (2), (3), and (4), The “183 response” is transferred in the procedures (5) and (6).

  However, in the communication system 200B shown in FIG. 7, it is assumed that the early media generation source device 20 in the destination network 53B executes step S31 shown in FIG. That is, the early media EM2 generated by the destination network 53B itself is preferentially transmitted over the early media EM1 transmitted from the destination terminal 54 which is the preceding node device 40. Accordingly, the advance guidance procedure is activated in the destination network 53B, and the early media EM2 generated in the destination network 53B is transferred to the source network 52.

  In addition, the early media generation source device 20 in the destination network 53B generates “UE” of the early media generation source information Pems in the “183 response” received in the procedure of (4), and generates the early media of the destination network 53B itself. It is overwritten with “AS” which is the source information Pems. This “AS” means that the early media EM2 is an “application server”, that is, early media generated by equipment other than the user.

  As shown in FIG. 7, the early media authorization control device 10 existing in the originating network 52 uses the “AS” of the early media generation source information Pems included in the “183 response” received in the procedure (5). In order to recognize that the early media EM2 received from the destination network 53B is an early media generated by equipment other than the user, the media path of the early media EM2 is opened according to the policy assigned to itself. Therefore, the early media EM2 is transferred from the calling network 52 to the calling terminal 51.

<When applied to parallel forking>
FIG. 8 shows an operation example of a communication system including the early media authorization control system in the embodiment of the present invention. In the communication system shown in FIG. 8, the calling terminal 61 can simultaneously connect and communicate with a plurality of called terminals 63 (# 1) and 64 (# 2) via the network 62. .

  Here, it is assumed that the plurality of destination terminals 63 (# 1) and 64 (# 2) are, for example, tablet terminals and smart phones used by the same user who contracts one communication line. ing. In addition, it is assumed that each of the destination terminals 63 (# 1) and 64 (# 2) includes the above-described early media generation source device 20.

  In the communication system of FIG. 8, the network 62 incorporates the above-mentioned early media authorization control device 10. However, when the operator who allows communication of the early media between users manages the network 62. The early media EM21 and EM22 of the receiving terminals 63 and 64 can be transferred to the calling terminal 61.

  In the communication system shown in FIG. 8, the parallel forking specified in “IETF RFC 3261: SIP: Session Initiation Protocol” is used to select an early media communication target from among a plurality of “18x responses” generated in a terminal or a network. It is assumed that the above-mentioned early media generation source information Pems is used as hint information for selecting one “18x response”.

  In the operation sequence shown in FIG. 8, when the calling terminal 61 transmits an “INVITE request” in the procedure (1), the network 62 sends “INVITE request” to both the called terminals 63 and 64 in the procedure (2). ".

  Each of the destination terminals 63 and 64 transmits the SDP including the early media generation source information Pems to the network 62 as “183 Session Progress” in the procedure of (3). These “183 Session Progress” are transferred from the network 62 to the calling terminal 61. Here, the early media generation source information Pems in the SDP transmitted by the destination terminal 63 (# 1) includes “UE # 1” representing the destination terminal 63, and is transmitted by the destination terminal 64 (# 2). The early media generation source information Pems in the SDP includes “UE # 2” indicating the destination terminal 64.

  Therefore, the transmission source of the early media EM21 is the destination terminal 63 (# 1) based on the early media generation source information Pems included in “183 Session Progress” received from each destination terminal in the procedure of (3). Yes, it can be recognized that the transmission source of the early media EM22 is the destination terminal 64 (# 2).

  Then, the CPU that controls the calling terminal 61 uses “UE # 1” and “UE # 2” of the received early media generation source information Pems as selection hint information in step S81, and uses a plurality of early media EM21 and EM22. A software program for automatically selecting one early medium to be reproduced is executed. With respect to the criteria and priority for selecting one early medium using hint information, for example, predetermined information is held on the calling terminal 61 in the form of a table or the like. As a result, the CPU that controls the calling terminal 61 can easily select more appropriate early media in step S81.

  In the operation sequence shown in FIG. 8, the calling terminal 61 receives the early media EM21 transmitted from the called terminal 63 and the early media EM22 transmitted from the called terminal 64 via the network 62, respectively. Since the calling terminal 61 preferentially selects the called terminal 63 (# 1) side in step S81, the early media EM21 (# 1) is reproduced in step S82.

<Advantages of Early Media Authorization Control System>
In a communication system in which multiple networks are connected to each other, the SDP session information is rewritten at the intermediate node of the call connection path. The source of the media cannot be identified. However, in the above-described early media authorization control system, the early media generation source device 20 assigns early media generation source information Pems representing an actual generation source to a location (see FIG. 5) that is not affected by rewriting in the intermediate node. connect. As a result, the system on the network managed by one operator can reliably identify the system on the network managed by the other operator or the generation source of the early media sent from the terminal connected to the network. .

  The system can appropriately control opening and closing of the media path according to the generation source of the media. Therefore, as in the communication systems 200A and 200B shown in FIG. 6 and FIG. 7, when connecting the operator network (53A, 53B) that allows early media between users and the carrier network (52) that does not allow, On the unacceptable carrier network (52) side, it is possible to execute selective control such as allowing early media EM2 as free prior guidance from the called network to be communicated while blocking early media EM1 from the called terminal 54.

  Further, the early media generation source device 20 generates information indicating that the device type of the early media generation source device 20 itself is at least one of the provider network device and the user terminal as the early media generation source information Pems. . Thereby, the early media authorization control apparatus 10 can specify whether the corresponding early media belongs to a business operator (service provider side) or a user. Therefore, in a network that does not allow early media transferred between users, it becomes easy to distinguish between early media based on prior guidance and early media transferred between users and appropriately switch communication of media paths.

  The early media generation source device 20 generates unique identification information for identifying the network to which the early media generation source device 20 belongs as the early media generation source information Pems. Thereby, the early media authorization control apparatus 10 can specify the network to which the corresponding early media belongs.

  The early media generation source device 20 generates unique identification information that can identify the early media generation source device 20 itself as the early media generation source information Pems. As a result, the early media authorization control apparatus 10 can distinguish the generation source of the early media.

  Further, as in steps S31 and S32 shown in FIG. 3, the early media generation source device 20 identifies whether the received SIP / SDP message includes the early media generation source information Pems, and receives it. A plurality of different generation sources by sending at least one of the early media generation source information included in the SIP / SDP message and the early media generation source information pre-assigned to the SIP message in a SIP message. Even when the early media exists, appropriate early media can be selectively transmitted.

10 Early Media Authorization Control Device 11 Proxy 11a SIP / SDP Processing Unit 12 Media Processing Unit 20 Early Media Generation Source Device 21 UAS
21a SIP / SDP processing unit 22 Media processing unit 30 Originating terminal 31 UAC
32 Media processing unit 40 Predecessor node device 51 Originating terminal 52 Originating network 53A, 53B Terminating network 54 Terminating terminal 61 Originating terminal 62 Network 63, 64 Terminating terminal 200A, 200B Communication system ST1, ST2, ST3, ST4, ST5 Status Pems Early media generation source information C1, C2, C3, C4, C5 Information allocation example EM1, EM2, EM21, EM22 Early media

Claims (8)

An early media authorization control device that controls the communication of early media, and an early media generation source that attempts to transmit early media. An early media authorization control system comprising a device,
In the negotiation process before session establishment using the session establishment protocol, the early media generation source apparatus includes the early media generation source information included in the SIP message of the session establishment protocol and transmits it to the early media authorization control apparatus. / SDP processing unit
The early media authorization control device itself holds generation source reference information that can be used to identify approval / disapproval for the early media generation source information, and receives the received early media generation source information and the generation source reference information. And a second SIP / SDP processing unit for identifying communication of the early media.
Early media authorization control system characterized by that. The early media generation source device further includes a media processing unit that opens or closes the path of the early media according to a path opening instruction from the first SIP / SDP processing unit,
The early media authorization control device further includes a media processing unit that opens or closes the path of the early media in response to a path opening instruction from the second SIP / SDP processing unit.
2. The early media authorization control system according to claim 1, wherein: The early media generation source device generates, as the early media generation source information, information indicating that its own device type is at least one of a provider network device and a user terminal.
2. The early media authorization control system according to claim 1, wherein: The early media generation source device generates unique identification information for identifying the network to which the device belongs as the early media generation source information.
2. The early media authorization control system according to claim 1, wherein: The early media generation source device generates unique identification information capable of specifying its own device as the early media generation source information.
2. The early media authorization control system according to claim 1, wherein: The early media generation source device identifies whether or not the early media generation source information is included in the received SIP / SDP message, and the early media generation source information included in the received SIP / SDP message; Including at least one of the early media generation source information pre-assigned to the SIP message in the SIP message;
2. The early media authorization control system according to claim 1, wherein: The early media generation source device has the early media generation source information at a location that is not affected by the rewrite in the SIP / SDP message even when the session information is rewritten in an intermediate node of the call connection path. Send including
2. The early media authorization control system according to claim 1, wherein: An early media authorization control device that controls the communication of early media, and an early media generation source that attempts to transmit early media. An early media authorization control method for controlling a communication system comprising:
In negotiation processing before session establishment using a predetermined session establishment protocol, early media generation source information is included in a SIP message and transmitted from the early media generation source device to the early media authorization control device.
The early media authorization control device compares the early media generation source information received from the early media generation source device with generation source reference information prepared in advance to identify communication of the early media.
An early media authorization control method characterized by the above.

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