JP4740898B2 - Third-party call control (3PCC) system and 3PCC implementation method in an IP communication network having a plurality of IP address systems - Google Patents

Description

  The present invention relates to a technique for realizing third party call control (3PCC) in an IP communication network having a plurality of IP address systems.

  By performing call control using SIP (Session Initiation Protocol) from a third party such as an application server such as click-to-dial or video conference service, two or more subscriber terminals (devices such as media servers) 3PCC (Third Party Call Control) has been proposed as a method for establishing a session for IP media communication between them (see Non-Patent Document 1). In 3PCC, a session between a plurality of terminals is established upon activation from the application server 10 and communication such as voice or video conference call is performed. As a 3PCC implementation method of Non-Patent Document 1, communication control in an IP communication network having the same IP address system will be briefly described with reference to FIG. FIG. 7 shows the application server 10, the first terminal 20, and the second terminal 60. In such a configuration, the SIP control is performed between the application server 10 and the first terminal 20 and between the application server 10 and the second terminal 60. On the other hand, media communication is performed between the first terminal 20 and the second terminal 60 without going through the application server 10. As described above, when 3PCC is realized in an IP communication network having the same IP address system, SIP control and media communication can be performed through different IP packet paths.

  On the other hand, a media IP address and a port number for performing IP media communication between two or more subscriber terminals are described in an SIP message by SDP (Session Description Protocol) or the like, and IMS (IP Multimedia Subsystem) is set. In the next-generation network to be adopted, it is exchanged via a service control function (Core IMS function in which various SIP call processing functions are provided) corresponding to a SIP server such as CSCF or IBCF (Non-Patent Document 2, Non-Patent Document 3). reference). This service control function has an ALG (Application Level Gateway) function to rewrite the contents of the protocol description, and NAT (Network Address Translation) or NAPT (Network Address Port Translation) is performed in a transport function such as BGF for media communication. In this case, since the media IP address and the port number described in SDP or the like in the SIP message are rewritten to those corresponding to NAT, the network path of the media is the same as the network path of the SIP message. Non-Patent Document 3 describes a mutual cooperation method of AF corresponding to a service control function, RACS corresponding to a transport control function, and BGF corresponding to a transport function.

  Here, the AS operator network in which the application server 10 (3PCC is installed) and the operator network in which the server control function connected to the application server 10 exists have different IP address systems, and the AS operator network. When 3PCC is realized in a system in which IP address and port number conversion such as NAT is performed between the network and the carrier network, the media network path and the SIP message network path must be the same for the above reasons. Therefore, the media stream must pass through the AS operator network.

  In a system in which the IP address system of the network in which the 3PCC application server 10 that performs only call control exists and the network in which the service control function exists are different, the media stream must pass through the AS carrier network for the above reasons. However, since it is requested by the AS to set an address for which NAT support has already been set in the transport function, NAT setting cannot be performed and 3PCC cannot be realized.

RFC 3725, “Best Current Practices for Third Party Call Control (3pcc) in the Session Initiation Protocol (SIP),” Apr. 2004.

3GPP TS 23.228 v7.6.0, “IP Multimedia Subsystem (IMS); Stage 2,” Dec. 2006.

ETSI TISPAN ES 282 007 v1.1.1, “IP Multimedia Subsystem (IMS); Functional architecture,” June, 2006.

  An object of the present invention is to provide a technique for realizing 3PCC in a case where a network in which a server for implementing 3PCC exists and a network in which a service control function exists are different in IP address system.

In the invention according to one aspect of the present invention, a media packet loopback function is provided at the entrance of the application server. In particular,
A third-party call control system according to an aspect of the present invention includes an AS operator network in which an application server that implements at least third-party call control (3PCC) is present and a service control function in an IP communication network. In a third party call control system in which a carrier network has different IP address systems, the application server returns a media loop to which a predetermined address is assigned to enable setting of address conversion in the service control function. It has a function. The present invention is not limited to an apparatus, and may be realized as an invention of a method or program that can be realized by the apparatus.

  According to the present invention, in a system having a NAT function between an application server network and a service control function network, 3PCC can be realized without changing conventional protocol specifications such as SIP and SDP.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a system to which a method for realizing 3PCC according to an embodiment of the present invention is applied. The system shown in FIG. 1 includes an AS provider network 1, a first terminal network 2, a first provider network 3, a third provider network 4, and a second provider network 5. The second terminal network 6 is shown. Here, it is assumed that communication is performed between the first terminal 20 in the first terminal network 2 and the second terminal 60 in the second terminal network 6. The first to third operator networks 3 to 5 are separate operator networks and may have different IP address systems, but may be the same operator network and the same IP address system. Further, it is assumed that the AS operator network 1 and at least the third operator network 4 have different IP address systems.

In FIG. 1, an AS operator network 1 includes an application server (AS) 10, and first to third operator networks 3 to 5 include service control functions 32, 42, and 52, respectively, Port functions 34, 44, 54.
With this configuration, in this embodiment, the control signal is transmitted between the first terminal 20 and the second terminal 60 via the service control functions 32, 42, 52 and the AS 10. Transfer is possible via the transport functions 34, 44, 54 and the AS 10. The reason why 3PCC can be realized by this embodiment will be described below.

  FIG. 2 is a diagram showing functions of the conventional application server (AS) 10 and signal flows in the AS 10. FIG. 3 is a diagram showing a schematic configuration of a system including the application server 10 having the configuration shown in FIG. 2. In a system in which the IP network of the AS network and the network having the service control function are different, the transformer is It is a conventional block diagram with the subject which cannot perform NAT setting in a port function. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 4 shows a conventional 3PPC sequence in which there is a problem that NAT setting cannot be performed in the transport function in a system having a different IP address system between the AS network and the network having the service control function. This sequence is based on the Flow I sequence of Non-Patent Document 1.

  In FIG. 2, the AS 10 receives an activation signal and activates 3PCC, etc., an activation acceptance function 11, a first signal generation function 12 that generates a signal such as SIP, and a transfer of a signal such as SIP. A signal transfer function 13 to be performed; a signal validity check function 14 for inputting a control signal to check the validity of the input signal; a first signal processing function 15; a second signal generation function 16; And a function 17. The specific signal flow is as follows.

The activation acceptance function 11 of the AS 10 activates the 3PCC process by a signal such as HTTP indicating that the user has clicked on the Web screen or an activation signal such as SOAP from another Web server. As a signal such as SOAP that activates the 3PCC processing, a signal based on a standard rule such as Parlay X is also assumed. In addition, an implementation form in which the Web server and the AS are the same server is also assumed.
Next, when the AS 10 starts 3PCC processing by the start reception function 11, the AS 10 generates a signal such as SIP for calling to the terminal side by the first signal generation function 12, and the terminal side ( Transfer the signal to the service control function.

  On the other hand, when the AS 10 receives a signal such as SIP (response signal) from the terminal side, the AS 10 checks that the description of the signal conforms to the rule by the signal validity check function 14, and The signal processing function 15 extracts signal information, the signal second signal generation function 16 generates a signal for calling the other terminal, and the signal transfer function 17 transmits the signal to the other terminal. Forward. The AS 10 can call two or more terminals, but when there is no other terminal to call, the AS 10 performs the first signal processing function and ends the process.

  In the above configuration, as described above, in a system in which the IP address system of the network in which the AS 10 exists and the network in which the service control function exists are different, the media stream must pass through the AS provider network 1. However, because the transport function 44 requires the AS 10 to set an address for which NAT support has already been set, NAT setting cannot be performed, and 3PCC cannot be realized (location indicated by x in FIG. 3). . The reason for this will be described with reference to FIG. FIG. 4 shows a flow when there is no SDP in the INVITE signal (Flow I of Non-Patent Document 1).

  First, an INVITE signal is transmitted from the AS 10 to the first terminal 20 via the service control functions 42 and 32. The first terminal 20 sends a 200 OK signal including offer1 to the AS 10. The address of the 200 OK signal is input to the AS 10 after NAT conversion is set by the service control functions 32 and 42. Here, in FIG. 4, in the service control function 42, “10.0.1.1 B ← 192.168.0.2 C” is set as the first NAT conversion setting (where B and C indicate port numbers, respectively). For example, “10.0.1.1 B” may be regarded as an address.

  Here, the AS 10 sends an INVETE signal including Offer1 (192.168.0.2 C) to the service control function 42. However, in the service control function 42, since NAT corresponding assignment to “192.168.0.2 C” has already been performed, a NAT request for the same “192.168.0.2 C” cannot be made. Therefore, the transport function 44 has a problem that NAT cannot be set. Further, the 200OK signal including answer1 from the second terminal 60 also has the same problem in the service control function 42, so that the NAT function cannot be set in the transport function 44. For this reason, 3PCC cannot be realized.

  Thus, in the present embodiment, this problem is solved by adding a media folding function to the AS 10. The configuration is shown in FIG. FIG. 5 is a diagram illustrating functions of the AS 10 according to the embodiment of the present invention and the flow of control signals thereof. FIG. 6 is a diagram showing a sequence when the AS 10 according to the present embodiment is applied. The AS 10 according to the present embodiment includes a media return setting function 18 and a media return function 19 in addition to the configuration of FIG.

  The media return setting function 18 assigns a return address to the media return function 19 in order to enable the NAT conversion setting in the service control function 42. This address is an address for opening a port according to the medium, and any address may be assigned. For example, it may be an AS10 address. In the example shown in FIG. Is given. Further, the number of media is not limited to one, and an address may be set according to the media.

  First, in FIG. 6, it is assumed that the first INVITE signal from the AS 10 includes Offer1 (192.168.0.1 A), and NAT conversion setting is performed according to this address. Here, when a 200 OK signal is transmitted from the first terminal 20 in response to the INVITE signal from the AS 10, a 200 OK signal including Answer 1 (192.168.0.1 F) is transmitted from the service control function 42 to the AS 10. Then, the media return setting function 18 performs the setting “192.168.0.1 G → 192.168.0.1 F” in the media return function 19. When a 200 OK signal is sent from the second terminal 60 side and a 200 OK signal including Answer2 (192.168.0.2 L) is sent from the service control function 42 to the AS 10, the media return setting function 18 A setting of “192.168.0.1 A → 192.168.0.1 L” is performed in the loopback function 19. The media return function 19 holds the correspondence of the media address assigned by the media return setting function 18.

As described above, the AS 10 is provided with the media folding function 19 to operate as follows.
The media address on the AS 10 side is assigned to the media address (including the port number) received from the first or second terminal 20 or 60 side, and the assigned media address is transmitted to the other terminal 20 or 60 side. The first or second terminal 20 or 60 transmits a media packet to the AS 10 via a transport function (not shown). The AS 10 returns the media packet received from the first or second terminal 20, 60 side to the other terminal 20, 60 side by the media return function 19 and transmits it. In the present embodiment, the media loopback function 19 is included in the AS 10, but may be arranged in another server.

  In the future, in the next generation network adopting IMS, it is assumed that the business provider providing the service control function differs from the business provider providing the application server. It is conceivable that the existing networks have different IP address systems and the two networks are connected via the NAT function.

According to the present invention, in a system having a NAT function between an application server network and a service control function network, 3PCC can be realized without changing conventional protocol specifications such as SIP and SDP.
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.
In addition, for example, even if some structural requirements are deleted from all the structural requirements shown in each embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the effect of the invention Can be obtained as an invention.

In a system in which the first network in which the application server that implements 3PCC exists and the second network in which the service control function having the ALG function exists have different IP address systems, the NAT control determination function and the media setting are included in the service control function. It is a figure which shows the structure which adds a function and implement | achieves 3PPC. It is a figure which shows the flow of the signal in the conventional application server. FIG. 2 is a conventional configuration diagram in which there is a problem that NAT setting cannot be performed in the transport function in a system having a different IP address system between an AS network and a network having a service control function. In a system where the IP address system of the AS network and the network where the service control function exists are different, there is a problem that the NAT setting cannot be performed in the transport function (for example, the one based on the Flow I sequence of Non-Patent Document 1) ). It is a figure which shows the flow of the control signal of a new application server. FIG. 11 is a sequence diagram for realizing 3PCC by a new application server function in a system in which an AS network and a network having a service control function have different IP address systems. It is a block diagram which implement | achieves 3PPC in the IP communication network which has the same IP address system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Provider network 2 ... 1st terminal network 3 ... 1st provider network 4 ... 3rd provider network 5 ... 2nd provider network 6 ... 2nd terminal network 10 ... Application server (AS)
DESCRIPTION OF SYMBOLS 11 ... Start reception function 12 ... 1st signal generation function 13 ... Signal transfer function 14 ... Signal correctness check function 15 ... 1st signal processing function 16 ... 2nd signal generation function 17 ... Signal transfer function 18 ... Media return Setting function 19 ... Media loopback function 20 ... First terminal 32, 42, 52 ... Service control function 34, 44, 54 ... Transport function 60 ... Second terminal

Claims (5)

In an IP communication network, an AS carrier network in which an application server that implements at least third-party call control (3PCC) exists and a carrier network in which a service control function exists have different IP address systems. In a party call control system,
The third party call control system, wherein the application server comprises a media loopback function to which a predetermined address for enabling address translation in the service control function is assigned. The third-party call control system according to claim 1, wherein the application server further includes a media return setting function for setting the predetermined address in the media return function. The third-party call control system according to claim 1, wherein the AS operator network further includes a server, and the media loopback function is provided in the server. 4. The third-party call control system according to claim 1, wherein the predetermined address includes an address of an application server and a port number related to transmission of a media packet. . In an IP communication network, an AS carrier network in which an application server that implements at least third-party call control (3PCC) exists and a carrier network in which a service control function exists have different IP address systems. In a third party call control method applied to a party call control system,
A call control signal including an address and a port number is transmitted from the application server to the terminal via the service control function,
3. A third party call control method comprising performing media loopback setting based on a control signal from the terminal so that address translation setting can be performed by the service control function.

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