JP5247534B2 - Method and system for establishing a plurality of sessions of different routes depending on home gateway - Google Patents

Description

  The present invention relates to a session establishment method and system in a home gateway that can be connected to an NGN (Next Generation Network) core network.

  The NGN core network is standardized by ITU-T (International Telecommunication Union-Telecommunication standardization sector) as a next-generation managed network. The NGN core network is suitable for a service of an application (for example, audio or video streaming) that requires real-time property in order to guarantee the QoS (Quality of Service) of the route. A session in the NGN core network is controlled based on SIP (Session Initiation Protocol).

  FIG. 1 is a system configuration diagram in which a home network and an NGN core network are connected.

  According to FIG. 1, a session control server is connected to an NGN core network (IPv6 network). The session control server is composed of CSCF (Call Session Control Function) / HSS (Home Subscriber Server) and one or more PCRFs (Policy and Charging Rules Function). The session control server 10 controls the session based on SIP and instructs the access gateway to perform gate control.

  A first access gateway AGW1 is connected between the NGN core network and the first access network, and a first home gateway HGW1 is connected between the first access network and the first home network, A first terminal UE1 is connected to the first home network. The second access gateway AGW2 is connected between the NGN core network and the second access network, and the second home gateway AGW2 is connected between the second access network and the second home network. The second terminal UE2 is connected to the second home network. Furthermore, the first access network and the second access network are interconnected via a non-core network (IPv4 network).

  According to FIG. 1, the home gateway HGW has an IP address for external connection given from the access network. When the home gateway HGW receives a session establishment request (INVITE request) from the terminal UE via the home network, the home gateway HGW generates a secure tunnel with the access gateway AGW. As a result, all communication traffic related to the terminal UE is communicated via this secure tunnel generated in the access network. A secure tunnel is established between one access gateway AGW and a number of home gateways HGW. Therefore, not only the load is concentrated on the access gateway AGW that executes QoS guarantee control, but also the equipment cost of the entire NGN core network increases.

  According to the technology described in Non-Patent Document 1, femtocells (home gateways) directly communicate with each other about SIP sessions, thereby realizing route optimization regarding data packets. Specifically, the femtocell operates as a SIP application level gateway and converts an IP address and a port number (see, for example, Non-Patent Document 2).

  Application level gateway is a firewall technology that controls access based on applications. The application level gateway converts the IP address of the payload and other information in addition to the conversion of the IP address and port number in the IP header in the NAT (Network Address Transform) function. This enables terminals in the home network to connect to the session control server using SIP.

"A Study on Media Data Path Optimization Using Femtocell", IEICE Society Conference 2008, B-6-38 “IETF Internet Draft, draft-rosenberg-sip-firewalls-00.txt (expired),“ Getting SIP through Firewallsand NATs ”, [online], [Search February 19, 2009], Internet <http: // www .jdrosen.net / papers / draft-rosenberg-sip-firewalls-00.txt>

  According to the technology described in Non-Patent Document 1, all traffic between home networks is directly communicated between femtocells. However, in order to realize QoS guarantee in the NGN core network, the traffic must pass through the access gateway AGW. Therefore, according to the technique described in Non-Patent Document 1, QoS guarantee cannot be realized.

  Further, according to the system of FIG. 1, the home gateway HGW cannot know the IPv4 address for external connection of the access network in the other home gateway HGW. Therefore, the technique described in Non-Patent Document 1 cannot be applied.

  Therefore, an object of the present invention is to provide a method and system for establishing a plurality of sessions of different routes depending on a home gateway. Thereby, the traffic of the media type that requires QoS guarantee is communicated via the access gateway AGW, and the traffic of the media type that does not require QoS guarantee is communicated directly between the home gateways HGW.

According to the present invention,
A session control server connected to the core network;
One or more access gateways connected between the core network and the access network;
A first home gateway connected between the access network and the first home network;
A first terminal connected to a first home network;
A second home gateway connected between the access network and the second home network;
A second terminal connected to a second home network,
A session establishment method in a system in which a first home gateway and a second home gateway are interconnected via a non-core network via an access network,
When the first home gateway receives a session establishment request from the first terminal, the first session is connected via the core network via the access gateway according to the media type in the session establishment request; A first step of determining to establish a second session for connection via a non-core network, and transmitting the session establishment request to the session control server via the access gateway;
When the second home gateway receives a session establishment request from the session control server, the first home gateway connects via the core network via the access gateway according to the media type in the session establishment request, A second step of determining to establish a second session connected via the core network and transmitting the session establishment request to the second terminal;
A third step in which the second home gateway transmits the session establishment response received from the second terminal to the session control server via the access gateway and updates the routing table;
The first home gateway has a fourth step of transmitting the session establishment response received from the session control server to the first terminal and updating the routing control table.

According to another embodiment of the session establishment method of the present invention,
The core network is an IPv6 network,
The non-core network is an IPv4 network,
For the first step,
The session establishment request transmitted by the first home gateway is an SDP (Specification
It is also preferable to include an IPv6 network prefix or an IPv4 address for each media part of (Description Protocol).

According to another embodiment of the session establishment method of the present invention,
Regarding the first step, the session establishment request transmitted by the first home gateway includes a media part for “information exchange” in addition to the SDP,
The address given to the external interface of the second home gateway is set to the first home gateway through the “information exchange” media session established between the first home gateway and the second home gateway. It is also preferable to further include a fifth step of transmitting to.

According to another embodiment of the session establishment method of the present invention,
It is also preferable to further include a sixth step of securing the second session between the first home gateway and the second home gateway connected via the non-core network by IPsec.

According to another embodiment of the session establishment method of the present invention,
The media type is preferably the flow type in the session, the establishment time, or the domain or subscription service type of the source terminal and the destination terminal.

According to the present invention,
A session control server connected to the core network;
One or more access gateways connected between the core network and the access network;
A first home gateway connected between the access network and the first home network;
A first terminal connected to a first home network;
A second home gateway connected between the access network and the second home network;
A second terminal connected to a second home network,
A system in which a first home gateway and a second home gateway are interconnected via a non-core network via an access network;
The first home gateway is
When a session establishment request is received from the first terminal, depending on the media type in the session establishment request, the first session connected via the core network via the access gateway and via the non-core network Route determining means for determining to establish a second session to be connected;
Session establishment request transmission means for transmitting the session establishment request received from the first terminal to the session control server via the access gateway;
A session establishment response receiving means for updating the path control table for the second session and transmitting the session establishment response to the first terminal when a session establishment response is received from the session control server via the access gateway; ,
The second home gateway is
When a session establishment request is received from the session control server, the first session connected via the core network via the access gateway and the non-core network are connected according to the media type in the session establishment request. Route determining means for determining to establish a second session with;
Session establishment request receiving means for transmitting a session establishment request received from the session control server via the access gateway to the second terminal;
Session establishment response transmission means for updating the routing control table for the second session and transmitting the session establishment response to the session control server via the access gateway when the session establishment response received from the second terminal is received. It is characterized by having.

According to another embodiment of the system of the present invention,
The core network is an IPv6 network,
The non-core network is an IPv4 network,
The session establishment request transmitted by the first home gateway preferably includes an IPv6 network prefix or an IPv4 address for each media part of SDP (Specification Description Protocol).

According to another embodiment of the system of the present invention,
The first home gateway session establishment request transmission means includes a media establishment for "information exchange" in the SDP in the session establishment request transmitted by the first home gateway,
It is also preferable that the first home gateway and the second home gateway further have a secure path communication means for exchanging addresses assigned to the external interface with each other through an established “information exchange” media session. .

According to another embodiment of the system of the present invention,
Secure path communication means, a second session between the first home gateway and the second home gateway connected via the non-core networks, it is also preferable to secure by IPsec.

According to another embodiment of the system of the present invention,
The media type is preferably the flow type in the session, the establishment time, or the domain or subscription service type of the source terminal and the destination terminal.

  According to the session establishment method and system of the present invention, media type traffic requiring QoS guarantee is communicated via the access gateway AGW, and media type traffic not requiring QoS guarantee is directly between the home gateways HGW. Communication.

It is a system configuration diagram in which a home network and an NGN core network are connected. It is a system configuration diagram in the present invention. It is a 1st sequence diagram in this invention. This is an SDP description of the INVITE request in S302 of FIG. This is an SDP description of a 200OK response in S306 of FIG. 4 is a route control table for a home gateway and an access gate in FIG. 3. It is a 2nd sequence diagram in this invention. This is an SDP description of the INVITE request in S702 of FIG. This is an SDP description of a 200OK response in S706 of FIG. 8 is a route control table for a home gateway and an access gate in FIG. It is a functional block diagram of the home gateway in this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a system configuration diagram according to the present invention.

  For example, it is assumed that the first terminal UE1 and the second terminal UE2 communicate by videophone (sound and video) and transfer an image file such as a photograph. According to the system of FIG. 2, as compared with FIG. 1, traffic of a media type that requires QoS guarantee (for example, voice or video) communicates via the access gateway AGW. On the other hand, media type traffic that does not require QoS guarantee (for example, file transfer) is directly communicated between the home gateways HGW. Therefore, all communication traffic between the first terminal UE1 and the second terminal UE2 does not go through the NGN core network. Therefore, the concentration of traffic on the access gateway AGW and the NGN core network can be reduced.

Two addresses are allocated to the first home gateway HGW1 as follows.
IPv4 address: [192.168.0.100]
IPv6 network prefix: [1000: 123: 1000 :: / 64]
In addition, two addresses are assigned to the second home gateway HGW2 as follows.
IPv4 address: [10.0.0.200]
IPv6 network prefix: [2000: 234: 2000 :: / 64]
It is assumed that the first terminal UE1 and the second terminal UE2 have already completed SIP registration with the session control server 10.

  FIG. 3 is a first sequence diagram in the present invention.

(S301) The first terminal UE1 transmits a session establishment request (INVITE request) to the first home gateway HGW1 in order to start a SIP session. The first home gateway HGW1 operates as a SIP proxy for the external network.

(S302) When receiving the INVITE request, the first home gateway HGW1 executes processing of the application level gateway (ALG). The first home gateway HGW1 determines the establishment of two sessions according to the media type of the INVITE request.
(First session) Connection between the first access gateway AGW1 and the second access gateway AGW2 via the IPv6 network (Second session) between the first home gateway HGW1 and the second home gateway HGW2 Connect via IPv4 network

  The session type corresponding to the media type is defined in advance in the policy table. For example, audio / video is assigned to the first session, and file is assigned to the second session.

  Then, the first home gateway HGW1 transmits an INVITE request to the session control server 10 via the first access gateway AGW1.

  FIG. 4 is a description of SDP (Specification Description Protocol) of the INVITE request in S302.

  According to FIG. 4, an IP address (c line) is described for each media part (m line) of the SDP. The IPv6 network prefix of the first home gateway HGW1 is described in the media part of audio (audio) and video (video). Further, the IPv4 address of the first home gateway HGW1 is described in the media part of the file (message). The session control server 10 can recognize only the IPv6 address, and the IPv4 address is usually ignored.

(S303) The session control server 10 transmits the received INVITE request to the second home gateway HGW2 via the second access gateway AGW2.

  The second home gateway HGW2 obtains the IPv6 network prefix of the first home gateway HGW1 for the audio / video from the SDP description of the INVITE request, and the IPv4 address of the first home gateway HGW1 for the file. get.

(S304) When receiving the INVITE request, the second home gateway HGW2 executes processing of the application level gateway (ALG). The second home gateway HGW2 determines the establishment of two sessions according to the media type of the INVITE request.
(First session) Connection between the first access gateway AGW1 and the second access gateway AGW2 via the IPv6 network (Second session) between the first home gateway HGW1 and the second home gateway HGW2 Connect via IPv4 network

  Then, the second home gateway HGW2 transmits an INVITE request to the second terminal UE2 via the second home network.

(S305) When receiving the INVITE request, the second terminal returns a session establishment response (200OK response) to the second home gateway HGW2.

(S306) Upon receiving the 200OK response, the second home gateway HGW2 executes the application level gateway process. The second home gateway HGW2 executes gate control for the following two sessions.
(First session) About audio (audio) and video (video), connected via the IPv6 network between the first access gateway AGW1 and the second access gateway AGW2 (second session) About the file (message) Connection between the first home gateway HGW1 and the second home gateway HGW2 via the IPv4 network

  The gate of the second home gateway HGW2 is based on the IPv6 network prefix and IPv4 address of the first home gateway 31 and the second home gateway 32, and the port number and transport protocol for transmitting and receiving voice, video and file packets. Be controlled.

  Then, the second home gateway HGW2 transmits a 200OK response to the session control server 10 via the second access gateway AGW2.

  FIG. 5 is a description of the SDP of the 200OK response in S306 of FIG.

  According to FIG. 5, the IPv6 network prefix of the second home gateway HGW2 is described in the media part of audio and video. In the media part of the file (message), the IPv4 address of the second home gateway HGW2 is described.

  FIG. 6 is a route control table of the home gateway and the access gateway in FIG. Here, the route control table of the second home gateway HGW2 is set as shown in FIG. 6C, for example.

(S307) The session control server 10 transmits a gate control request to the second access gateway AGW2. In the gate control request, gate control information for the following one session is described.
(First session) Connection between the first access gateway AGW1 and the second access gateway AGW2 via the IPv6 network for audio and video

  The gate of the first access gateway AGW1 is controlled by the IPv6 addresses of the first home gateway 31 and the second home gateway 32, the port number for transmitting and receiving voice and video packets, and the transport protocol.

(S308) Upon receiving the gate control request, the second access gateway AGW2 updates the routing table to establish the first session. Thereafter, the second access gateway AGW2 returns a gate control response to the session control server 10. Here, the route control table of the second access gateway AGW2 is set, for example, as shown in FIG.

(S309) Similar to S307, the session control server 10 transmits a gate control request to the first access gateway AGW1.

(S310) Similar to S308, the first access gateway AGW1 returns a gate control response to the session control server 10. Here, the route control table of the first access gateway AGW1 is set as shown in FIG. 6B, for example.

(S311) The session control server 10 transmits a 200OK response to the first home gateway HGW1 via the first access gateway AGW1. Here, the first home gateway HGW1 acquires the IPv6 network prefix of the second home gateway HGW2 for audio and video, and acquires the IPv4 address of the second home gateway HGW2 for files. Here, the route control table of the first home gateway HGW1 is set as shown in FIG. 6D, for example.

(S312) When the first home gateway HGW1 receives the 200OK response, the first home gateway HGW1 executes the application level gateway process and then transmits the 200OK response to the first terminal UE1.

  Through S301 to S312, the first session is selected for audio and video that require QoS guarantee, and the second session is selected for file that does not require QoS guarantee. Is done.

(S313) Thereafter, the first terminal UE1 and the second terminal UE2 communicate voice and video data packets via the IPv6 network, and communicate file data packets via the IPv4 network. In the access network between the home gateway HGW and the access gateway AGW, a secure tunnel is constructed.

  According to the first sequence in FIG. 3, the home gateways HGW can know the IPv4 address from each other. However, it is not preferable from the viewpoint of security to incorporate an IPv4 address even though it has not been decided whether or not to directly communicate between home gateways.

  Also, according to the first sequence in FIG. 3, a secure tunnel is configured by IPsec between the home gateway HGW and the access gateway AGW. However, the home gateways HGW are not secure and are not preferable from the viewpoint of security.

  In order to solve these problems, the second sequence will be described.

  FIG. 7 is a second sequence diagram in the present invention. In the following, only the sequence different from that in FIG. 3 will be described with reference to FIG.

(S702) When the first home gateway HGW1 receives an INVITE request from the first terminal UE1, the first home gateway HGW1 executes an application level gateway process.

  FIG. 8 is a description of the SDP of the INVITE request in S702 of FIG.

  According to FIG. 8, the IPv6 network prefix of the first home gateway HGW1 is described in the media part of audio (audio) and video (video). An arbitrary value (a.b.c.d) is described as an IPv4 address in the media part of the file (message). Further, according to FIG. 8, a media part for information exchange (application) is further added. Then, the first home gateway HGW1 transmits an INVITE request to the session control server 10 via the first access gateway AGW1.

(S704) When receiving the INVITE request from the session control server 10, the second home gateway HGW2 executes the application level gateway process. Then, the second home gateway HGW2 deletes the media part for information exchange from the SDP of the INVITE request. Then, the second home gateway HGW2 transmits the INVITE request to the second terminal UE2 via the second home network.

(S706) When the second home gateway HGW2 receives a 200OK response from the second terminal UE2, the second home gateway HGW2 executes an application level gateway process.

  FIG. 9 is an SDP description of the 200OK response in S706 of FIG.

  According to FIG. 9, a media part for information exchange (application) is further added. Then, the second home gateway HGW2 transmits a 200OK response to the session control server 10 via the second access gateway AGW2.

  FIG. 10 is a route control table of the home gateway and the access gateway in FIG. Here, the route control table of the second home gateway HGW2 is set as shown in FIG. 10C, for example. In step S706, the second home gateway HGW2 does not know the IPv4 address of the first home gateway HGW1.

(S707) The session control server 10 transmits a gate control request to the second access gateway AGW2. In the gate control request, gate control information for the first session is described. Here, as compared with FIG. 3 (S307), the first session includes not only audio and video but also information exchange (application).

(S708) After receiving the gate control request, the second access gateway AGW2 returns a gate control response to the session control server 10. Here, the route control table of the second access gateway AGW2 is set as shown in FIG. 10A, for example.

(S710) Similar to S708, the first access gateway AGW1 returns a gate control response to the session control server 10. Here, the route control table of the first access gateway AGW1 is set as shown in FIG. 10B, for example. In step S710, the first home gateway HGW1 does not know the IPv4 address of the second home gateway HGW2.

(S711) The session control server 10 transmits a 200OK response to the first home gateway HGW1 via the first access gateway AGW1. Here, the route control table of the first home gateway HGW1 is set as shown in FIG. 10D, for example.

(S712) The first home gateway HGW1 sends its IPv4 address [192.168.0.100] and DH (Diffie-Hellman) information to the second gateway via the first access gateway AGW1 and the second access gateway AGW2. Send to home gateway HGW2. Thereby, the second home gateway HGW2 knows the IPv4 address of the first home gateway HGW1.

  On the other hand, the second home gateway HGW2 sends its own IPv4 address [10.0.0.200] and DH (Diffie-Hellman) information to the first access gateway AGW1 and the second access gateway AGW2. To the home gateway HGW1. Thereby, the first home gateway HGW1 knows the IPv4 address of the second home gateway HGW2. A common key is acquired from the DH information.

(S713) A secure path by IPsec is established between the first home gateway HGW1 and the second home gateway HGW2 using IKEv2. As the mutual authentication information required by IKEv2, the shared key generated in S712 is used.

(S714) The first home gateway HGW1 transmits a 200OK response to the first terminal UE1.

(S715) Thereafter, the first terminal UE1 and the second terminal UE2 communicate audio and video data packets via the IPv6 network, and communicate file data packets via the IPv4 network. A secure tunnel is constructed in the access network between the first home gateway HGW1 and the second home gateway HGW2.

  FIG. 11 is a functional configuration diagram of the home gateway in the present invention.

  The home gateway 3 is connected between the home network and the access network, and includes a media data relay transfer unit 301, a secure path communication unit 302, a route control table 303, a route determination unit 304, and a session control unit (session establishment). A request transmission unit 305, a session establishment request reception unit 306, a session establishment response reception unit 307, a session establishment response transmission unit 308), and an application level gateway processing unit 309. These functional components excluding the interface unit are realized by executing a program that causes a computer mounted on the home gateway 3 to function.

  The media data relay transfer unit 301 transfers the media data to either the first session or the second session according to the path control table 303.

The route determination unit 304 determines to establish the following two sessions for the requested session according to the media type.
(First session) Connected between the first access gateway AGW1 and the second access gateway AGW2 via the IPv6 network (second session) between the first home gateway HGW1 and the second home gateway HGW2 Connect via IPv4 network

  The session type corresponding to the media type is defined in advance in the policy table. For example, audio / video is assigned to the first session, and file is assigned to the second session. Here, the media type is preferably a flow type in a session, an establishment time, or a domain or a subscription service type of a source terminal and a destination terminal. For example, the second session to be connected via the IPv4 network can be selected according to the establishment time.

  The session establishment request transmission unit 305 transmits the session establishment request received from the first terminal UE1 to the session control server 10 via the first access gateway. Here, the session establishment request transmission unit 305 has two methods for notifying the counterpart home gateway of the IPv4 address. The first method includes an IPv6 network prefix or an IPv4 address for each media part of SDP (Specification Description Protocol) in a session establishment request to be transmitted. In the second method, a session establishment request to be transmitted is included by adding a media part for “information exchange” to the SDP. Thus, the IPv4 address is notified through the generated information exchange path.

  When the session establishment response reception unit 307 receives a session establishment response from the session control server 10 via the first access gateway AGW1, the session establishment response reception unit 307 updates the routing control table 303 for the first session and the second session, An establishment response is transmitted to the first terminal UE1.

  The session establishment request receiving unit 306 transmits the session establishment request received from the session control server 10 via the second access gateway AGW2 to the second terminal UE2.

  When the session establishment response transmission unit 308 receives the session establishment response received from the second terminal UE2, the session establishment response transmission unit 308 updates the routing control table 303 for the first session and the second session, and sends the session establishment response to the second It transmits to the session control server 10 via the access gateway AGW2.

  In the secure path communication unit 302, the first home gateway and the second home gateway exchange the IPv4 address assigned to the external interface with each other via the established “information exchange” media session. In addition, the secure path communication unit 302 secures the second session between the first home gateway and the home gateway 2 connected via the non-core network by IPsec.

  As described above in detail, according to the session establishment method and system of the present invention, media type traffic that requires QoS guarantee is communicated via the access gateway AGW, and media type that does not require QoS guarantee. Traffic can be directly communicated between the home gateways HGW.

  In the various embodiments of the present invention described above, various changes, modifications, and omissions in the scope of the technical idea and the viewpoint of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 10 Session control server 21 1st access gateway 22 2nd access gateway 31 1st home gateway 32 2nd home gateway 301 Media data relay transfer part 302 Secure path communication part 303 Path control table 304 Path determination part 305 Session establishment Request transmission unit 306 Session establishment request reception unit 307 Session establishment response reception unit 308 Session establishment response unit 309 Application level gateway processing unit 41 First terminal 42 Second terminal

Claims (10)

A session control server connected to the core network;
One or more access gateways connected between the core network and the access network;
A first home gateway connected between the access network and a first home network;
A first terminal connected to a first home network;
A second home gateway connected between the access network and a second home network;
A second terminal connected to a second home network,
A method for establishing a session in a system in which a first home gateway and a second home gateway are interconnected via a non-core network via the access network,
When the first home gateway receives a session establishment request from the first terminal, the first home gateway connects via the access gateway via the core network according to the media type in the session establishment request. A first step of determining to establish a session and a second session connected via the non-core network, and transmitting the session establishment request to the session control server via the access gateway; ,
When the second home gateway receives a session establishment request from the session control server, the first home gateway connects via the access gateway via the core network according to the media type in the session establishment request. A second step of determining to establish a session and a second session to be connected via the non-core network, and transmitting the session establishment request to the second terminal;
A third step in which the second home gateway transmits the session establishment response received from the second terminal to the session control server via the access gateway and updates the routing table;
A session establishing method, comprising: a fourth step in which the first home gateway transmits a session establishment response received from the session control server to the first terminal and updates the routing control table. The core network is an IPv6 network;
The non-core network is an IPv4 network;
For the first step,
The session establishment method according to claim 1, wherein the session establishment request transmitted by the first home gateway includes an IPv6 network prefix or an IPv4 address for each media part of SDP (Specification Description Protocol). For the first step, the session establishment request sent by the first home gateway includes a media part for “information exchange” in addition to the SDP,
The address given to the external interface of the second home gateway is set to the first home gateway through the “information exchange” media session established between the first home gateway and the second home gateway. The session establishing method according to claim 1, further comprising a fifth step of transmitting to the session.   6. The method according to claim 6, further comprising a sixth step of securing a second session between the first home gateway and the second home gateway connected via the non-core network by IPsec. 4. The session establishment method according to 3.   The session establishment according to any one of claims 1 to 4, wherein the media type is a flow type in a session, an establishment time, or a domain or a subscription service type of a source terminal and a destination terminal. Method. A session control server connected to the core network;
One or more access gateways connected between the core network and the access network;
A first home gateway connected between the access network and a first home network;
A first terminal connected to a first home network;
A second home gateway connected between the access network and a second home network;
A second terminal connected to a second home network,
A system in which a first home gateway and a second home gateway are interconnected via a non-core network via the access network;
The first home gateway is
A first session connected via the core gateway via the access gateway according to a media type in the session establishment request when the session establishment request is received from the first terminal; and the non-core network Route determining means for determining to establish a second session to connect via
Session establishment request transmission means for transmitting the session establishment request received from the first terminal to the session control server via the access gateway;
Session establishment response receiving means for updating a route control table for a second session and transmitting the session establishment response to the first terminal when a session establishment response is received from the session control server via the access gateway; Have
The second home gateway is
A first session connected via the core gateway via the access gateway according to a media type in the session establishment request when the session establishment request is received from the session control server; and the non-core network Route determining means for determining to establish a second session to connect via
Session establishment request receiving means for transmitting a session establishment request received from the session control server via the access gateway to a second terminal;
When a session establishment response received from the second terminal is received, a session establishment response is transmitted for updating the routing control table for the second session and transmitting the session establishment response to the session control server via the access gateway. And a system. The core network is an IPv6 network;
The non-core network is an IPv4 network;
The system according to claim 6, wherein the session establishment request transmitted by the first home gateway includes an IPv6 network prefix or an IPv4 address for each media part of SDP (Specification Description Protocol). The session establishment request transmission means of the first home gateway includes a media part for “information exchange” in the SDP in the session establishment request transmitted by the first home gateway,
The first home gateway and the second home gateway further include secure path communication means for exchanging addresses given to the external interface with each other through an established “information exchange” media session. The system according to claim 6. The secure path communication means, according to the second session between the first home gateway and the second home gateway connected via the non-core networks, characterized by secure by IPsec Item 9. The system according to Item 8 .   The system according to any one of claims 6 to 9, wherein the media type is a flow type in a session, an establishment time, or a domain or a subscription service type of a transmission source terminal and a reception source terminal.

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