JP2011151456A - Traffic bypass system and traffic bypass method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform communication between a center and a number of bases exceeding the limit of the number of sessions allocated to the physical line of the center without increasing the physical line. <P>SOLUTION: When exceeding the upper limit of the number of sessions, the management server 5 of a service center notifies a base router 2b which has requested a connection of a bypass destination selected from among the ones in which the session is established at present. The base router 2b establishes the session with a base router 2a which is the notified bypass destination. Also, the center router 4 of the service center disconnects the session with the base router 2a and then establishes the session again by the total band of the using band of the base router 2a and the using band of the base router 2b. By using the established session, the data communication of a terminal 1a and a service providing server 6 is performed, and the data communication of a terminal 1b and the service providing server 6 is also performed by bypassing the established session. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a traffic detour system and a traffic detour method.

In a configuration in which the center server is accessed from terminals at a plurality of bases, the center normally establishes a session simultaneously with the plurality of bases.
Patent Document 1 describes a technique for preventing packet discard and improving packet throughput efficiency in a relay device that relays a packet transmitted from a terminal with a session established.

JP 2009-105952 A

There is a limit to the number of sessions that can be connected simultaneously to the physical line connecting the center and each site. Therefore, when the number of sessions with the number of bases exceeding the limit occurs, it is necessary to increase the physical line itself between the bases and the center and change to a network service with a larger number of accommodated sessions. Therefore, for example, even when it is necessary to temporarily increase the number of sessions, for example, a large number of sessions is required only at the time of data backup, it is necessary to change to a service that matches the largest number of sessions. Generally, services with a larger number of accommodated sessions are more expensive and costly to add physical lines, etc., so it is a wasteful investment if the service is changed when the number of sessions is the largest. May occur.
In the case of the technique disclosed in Patent Document 1, the number of sessions that can be connected is not increased.

  The present invention has been made in consideration of the above-described circumstances, and communicates with a number of bases and centers exceeding the limit of the number of sessions allocated to the physical line of the center without adding a physical line. It is an object of the present invention to provide a traffic bypass system and a traffic bypass method that can be enabled.

  In order to solve the above problems, the present invention is a traffic detour system in which a center communication device to which a service providing device is connected and a plurality of base communication devices to which terminals are connected are connected via a network, The detour source base communication device receives the detour destination communication address in response to the connection request transmitted to the center communication device, and establishes a session to the detour destination base communication device specified by the received communication address. Transmitting a request, establishing a session with the detour base communication device, and data between the terminal connected to the detour base communication device and the service providing device, A detour source data communication control unit that transmits and receives using the session established by the connection request unit, and the detour destination base communication device includes the detour source base A session establishment request received from a communication device, a bypass session establishment unit for establishing a session with the bypass base communication device, a disconnection request received from the center communication device, and a session established with the center communication device A center instruction disconnecting unit that disconnects the session, a session establishment request from the center communication device, a bandwidth that is wider than the disconnected session, and a bandwidth that establishes the received session of the used bandwidth with the center communication device While transmitting and receiving data between the increase reconnection unit, the terminal connected to the detour base communication device and the service providing device using the session established by the band increase reconnection unit, Data between the terminal connected to the bypass base communication device and the service providing device is transferred to the bypass session A detour destination data communication control unit that relays using the session established by the network establishment unit and the session established by the bandwidth increase reconnection unit, and the center communication device is the detour source base communication device A connection instructing unit that returns the communication address of the detour destination base communication device selected from the base communication devices that have already established a session when the connection request is received from the base station and the number of connections in the session has reached the upper limit And sending the disconnect request to the detour destination base communication device to disconnect the session with the detour destination base device, and then requesting a session establishment request to the detour destination base communication device and a wider bandwidth than before disconnection. A bandwidth increase session establishing unit that establishes a session of the used bandwidth transmitted with the detour base communication device, Data between the terminal connected to the detour base communication device and the service providing device, and data between the terminal connected to the detour base communication device and the service providing device, A traffic detour system comprising: a center data communication control unit that transmits and receives through the session established by the bandwidth increase session establishment unit.

  Further, in the traffic detour system described above, the connection request unit transmits a requested use band to the base communication device, and the band increase session establishment unit uses the disconnected established session. The total used bandwidth of the reserved bandwidth and the used bandwidth received from the bypass base communication device is transmitted to the bypass base communication device.

  Further, the present invention is the above-described traffic detour system, wherein the center communication device is a connection indicating an upper limit use band of a session with the base communication device and a use bandwidth of the session already established with the base communication device. A free bandwidth obtained by subtracting the used bandwidth of the established session from the upper limit used bandwidth is received from the detour source base communication device with reference to the storage location storing the location management table and the connection location management table. A connection destination selection unit that selects the base communication device that is equal to or greater than the requested use band, and the connection instruction unit returns a communication address of the base communication device selected by the connection destination selection unit; It is characterized by that.

  In the traffic detour system described above, the center communication apparatus stores a charge management table indicating a charge corresponding to a use band, and a use band of the session established with the base communication apparatus. Each of the used bandwidths of the base communication devices read from the storage unit and the requested used bandwidth received from the detour-source base communication device, and the calculated total bandwidths, respectively. And a connection destination selection unit that selects the base communication device with the lowest read rate, and the connection instruction unit is selected by the connection destination selection unit. The communication address of the base communication device is returned.

  Further, the present invention is the traffic detour system described above, wherein the center communication device stores the storage unit that stores information on the distance between the base communication devices and the base communication device that has established a session. A connection destination selection unit that selects the base communication device that is closest to the detour source base communication device, and the connection instruction unit is selected by the connection destination selection unit. The communication address of the base communication device is returned.

  Further, according to the present invention, in the traffic detour system described above, the detour source base communication device transmits a disconnect request to the detour destination base communication device, and disconnects the session with the detour destination base communication device. A detour destination disconnect request unit; and a detour destination disconnect notification unit that notifies the center communication device of disconnection of the detour destination base communication device, wherein the detour destination base communication device includes the detour source base communication device A detour source cutting unit that receives the disconnection request from a base communication device and disconnects the session with the detour source base communication device; and a narrower band than the session disconnected from the session establishment request from the center communication device The detour destination data communication control unit comprises: a band reduction reconnection unit that receives the band used and establishes a session of the received band using the center communication device. , Transmitting and receiving data between the terminal connected to the detour base communication device and the service providing device using the session established by the bandwidth reduction reconnection unit, the center communication device, After receiving the disconnection notification from the detour base communication device, transmitting a disconnection instruction to the detour destination base communication device and disconnecting the session with the detour destination base communication device, the detour destination A bandwidth reduction session establishment unit that transmits a session establishment request to a base communication device of the base station and a bandwidth that is narrower than the disconnected session, and establishes a session of the bandwidth to be used that is transmitted with the bypass base communication device The center data communication control unit further includes data between the terminal connected to the detour base communication device and the service providing device, Transmitted and received by the session-pass reduction session establishing unit has established, characterized in that.

  In the traffic detour system described above, the present invention further includes a disconnection request unit that transmits a disconnection request to the center communication device and disconnects the session with the center communication device. A detour destination disconnection instruction unit that receives the disconnection request from a previous base communication device, disconnects the session with the detour destination base communication device and transmits a connection disconnection request to the detour source base communication device; and A reconnection establishment unit that transmits a session establishment request to the detour-source base communication device and establishes a session with the detour-source base communication device, and the center data communication control unit includes the detour-source base communication device. Data sent between the terminal connected to the service and the service providing apparatus is transmitted / received by the session established by the reconnection establishment unit, and the detour source The base communication device receives the connection disconnection request from the center communication device, transmits a session establishment request from the detour destination cutting unit that disconnects the session with the detour base communication device, and the center communication device, A reconnection unit that establishes a session with the center communication device, and the detour source data communication control unit stores data between the terminal connected to the detour source base communication device and the service providing device. Transmission / reception is performed using the session established by the reconnection unit.

  The present invention also relates to a traffic detouring method used in a traffic detouring system in which a center communication device to which a service providing device is connected and a plurality of base communication devices to which terminals are connected are connected via a network. A connection request process in which the connection request unit transmits a connection request to the center communication device in the detour source base communication device, and a connection instruction unit in the center communication device from the detour source base communication device A connection instruction process for receiving a connection request and returning a communication address of the detour destination base communication device selected from the base communication devices that have been established when the number of connections in the session has reached the upper limit; In the base communication device that is the detour source, the connection request unit is detoured specified by the communication address received from the center communication device A connection request process for establishing a session with the detour destination base communication device by transmitting a session establishment request to the base communication device, and in the detour destination base communication device, a detour session establishing unit includes: A bypass session establishment process for receiving a session establishment request from the base communication device and establishing a session with the bypass source base communication device, and in the center communication device, a bandwidth increase session establishing unit includes the bypass destination base In the disconnection instruction process of transmitting a disconnection instruction to the communication device to disconnect the session with the detour destination base device, and in the detour destination base communication device, a center instruction disconnection unit sends the disconnection instruction from the center communication device. A center instruction disconnection process for receiving and disconnecting the established session with the center communication device; The bandwidth-increasing session establishment unit transmits a session establishment request to the detour base communication device and a use band wider than the disconnected session, and the use band transmitted to the detour base communication device In the process of establishing a bandwidth increase session for establishing the session and a base communication device at the detour destination, a bandwidth increase reconnection unit receives the session establishment request and the used bandwidth from the center communication device, and the center communication device And the increased bandwidth reconnection process for establishing the received session of the used bandwidth, and in the detour source base communication device, the detour source data communication control unit is connected to the detour source base communication device and the terminal The detour source data communication for transmitting / receiving data to / from the service providing apparatus using the session established in the connection request process. In the communication control process and the detour base communication device, the detour destination data communication control unit increases the bandwidth of the data between the terminal connected to the detour base communication device and the service providing device. Data is transmitted and received using the session established in the reconnection process, and data between the terminal connected to the bypass base communication device and the service providing apparatus is established in the bypass session establishment process. A detour destination data communication control process for relaying using the session established in the session and the bandwidth increase reconnection process, and a center data communication control unit connected to the detour destination base communication apparatus in the center communication apparatus Data between the terminal to be provided and the service providing device, and the terminal connected to the detour base communication device And data between the service providing device, a traffic detour method characterized by having a center data communication control step of receiving by the session established in said zone increases session establishment process.

  According to the above configuration, it is possible to communicate with a number of bases and centers exceeding the limit of the number of sessions allocated to the physical line without adding a physical line.

1 is an overall configuration diagram of a traffic detour system for describing an embodiment of the present invention. It is a block diagram which shows the structure of the base router by the embodiment. It is a block diagram which shows the structure of the center router by the embodiment. It is a block diagram which shows the structure of the management server by the embodiment. It is a figure which shows the data structure of the routing setting information by the embodiment. It is a figure which shows the data structure of the connection base management table by the embodiment. It is a figure which shows the data structure of the charge management table by the embodiment. It is a figure which shows the data structure of the distance management table between bases by the embodiment. It is a figure which shows the detour sequence by the embodiment. It is a figure which shows the detour sequence by the embodiment. It is a figure which shows the sequence of the detour source cutting | disconnection by the embodiment. It is a figure which shows the sequence of the detour destination cutting | disconnection by the embodiment. It is a figure which shows the example of a setting of routing setting information. It is a figure which shows the example of a setting of routing setting information. It is a figure which shows the example of a setting of a connection base management table. It is a figure which shows the example of a setting of a connection base management table. It is a figure which shows the example of a setting of a connection base management table. It is a figure which shows the setting content of a connection request. It is a figure which shows the setting content of a connection request response. It is a figure which shows the setting content of a disconnection notification. It is a figure which shows the setting content of a connection disconnection notification response. It is a figure which shows the setting content of a connection cutting | disconnection request | requirement. It is a figure which shows the setting content of a connection disconnection request response.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall configuration diagram of a traffic detour system for explaining an embodiment of the present invention. In FIG. 1, for example, a network N which is an IP (Internet Protocol) network such as an NGN (Next Generation Network) includes a base router 2 at each base, a center router 4 at a service center, and an SIP (Session). Initiation Protocol) server 3 is connected. One or more terminals 1 are connected to the base router 2 at each base, and a service for providing application services to the terminal 1 and a management server 5 for managing sessions to the center router 4 of the service center. The providing server 6 is connected. The terminal 1 is a computer terminal such as a personal computer or a workstation, for example. In addition, the SIP server 3 relays the SIP message by converting the destination address set in the SIP message into a real IP address. SIP is a session control protocol standardized by the Internet Engineering Task Force (IETF), and is used for operations such as starting, changing, and ending a session such as an IP phone. Note that when a SIP session is established, a bandwidth used for data communication can be designated.

  In the traffic detour system shown in FIG. 1, a center line accommodated in a service center (hereinafter also simply referred to as “center”) has a limitation on the number of SIP sessions established with all bases. For this reason, if the number of base routers 2 that request center connection exceeds the upper limit of the number of SIP sessions on the center line, a session cannot be established with the service center. Therefore, in the present embodiment, bases exceeding the upper limit are connected by bypassing the base router 2 of another base where a session with the service center is currently established. As a result, even if the number of base routers 2 requesting center connection exceeds the number of SIP sessions allowed by the center line, connection to the service center is possible without increasing the physical line on the center side. .

Hereinafter, a base router 2 that establishes a session with another base router 2 that has established a session with the service center and bypasses the session in the other base router 2 is referred to as a detour source base router or a detour source base router 2. The other base router 2 that bypasses the session between the detour source base router and the service center is referred to as a detour destination base router or a detour destination base router 2.
Further, the terminal 1 and the base router 2 at each base are represented by adding a code corresponding to the base. For example, the terminal 1 and the base router 2 at the base A are described as a terminal 1a and a base router 2a, respectively, and the terminal 1 and the base router 2 at a base B are described as a terminal 1b and a base router 2b, respectively.

FIG. 2 is a functional block diagram showing the internal configuration of the base router 2 as the base communication apparatus.
In FIG. 1, the base router 2 includes a communication interface unit 22, a session control unit 24, a storage unit 26, and a data communication control unit 28.

  The communication interface unit 22 transmits and receives data via the network N. The session control unit 24 performs session control by SIP. The storage unit 26 stores routing setting information used for IPsec. The data communication control unit 28 performs data communication control by IPsec using the routing setting information stored in the storage unit 26, and the routing setting stored in the storage unit 26 when the session is established or disconnected. Rewrite information.

  The session control unit 24 includes a connection request unit 241, a bypass destination disconnection request unit 242, a bypass destination disconnection notification unit 243, a bypass destination disconnection unit 244, a reconnection unit 245, a bypass session establishment unit 246, a center instruction disconnection unit 247, and a bandwidth increase. A reconnection unit 248, a detour source disconnection unit 249, a disconnection request unit 250, and a band reduction reconnection unit 251 are provided.

  The connection request unit 241 transmits a connection request to the management server 5 and establishes a session with the center router 4 or the detour destination base router. The detour destination cutting request unit 242 requests the detour destination base router to disconnect the session when the local router 2 is the detour source base router and the data communication is completed. The detour destination disconnection notification unit 243 notifies the management server 5 that the session with the detour destination base router has been disconnected. The detour destination cutting unit 244 receives a notification that the session between the detour destination base router and the center router 4 has been disconnected from the management server 5 and disconnects the session with the detour destination base router. The reconnection unit 245 receives a notification from the management server 5 that the detour destination base router has disconnected the session with the center router 4, and establishes a session directly with the center router 4.

  The bypass session establishment unit 246 receives a call connection request (session establishment request) from the bypass source base router when a session with the center router 4 is established, and establishes a session with the bypass source base router. The center instruction disconnecting unit 247 disconnects the session with the center router 4. After the session with the center router 4 is disconnected by the center instruction disconnection unit 247, the bandwidth increase reconnection unit 248 transmits the session with the bandwidth increased by the use bandwidth of the detour source base router according to the instruction from the center router 4. Reestablish with 4. The detour source cutting unit 249 disconnects the session with the detour source base router when the local router 2 is the detour destination base router and receives a disconnection request from the detour source base router. The disconnect request unit 250 requests the center router 4 to disconnect the session when the local router 2 is a detour base router and the data communication is terminated. After the session with the center router 4 is disconnected by the center instruction disconnection unit 247, the bandwidth reduction reconnection unit 251 transmits the session with the bandwidth reduced by the use bandwidth of the detour base router according to the instruction from the center router 4. Reestablish with 4.

  Hereinafter, the functional blocks in the terminal 1 at each site are represented by adding codes corresponding to the sites. For example, the storage unit 26 of the base router 2a of the base A is described as a storage unit 26a, and the storage unit 26 of the base router 2b of the base B is described as a storage unit 26b.

Next, the configuration of the center router 4 and the management server 5 as center communication devices will be described.
FIG. 3 is a functional block diagram showing the internal configuration of the center router 4. In the figure, the center router 4 includes a communication interface unit 42, a session control unit 44, a storage unit 46, and a data communication control unit 48.

  The communication interface unit 42 transmits and receives data via the network N. The session control unit 44 performs session control using SIP. The storage unit 46 stores routing setting information used for IPsec. The data communication control unit 48 performs data communication control by IPsec using the routing setting information stored in the storage unit 46, and the routing setting stored in the storage unit 46 when the session is established and disconnected. Rewrite information.

The session control unit 44 includes a connection establishment unit 441, a band increase session establishment unit 442, a band reduction session establishment unit 443, a reconnection establishment unit 444, and a disconnection unit 445.
The connection establishment unit 441 receives an instruction from the management server 5 and establishes a session with the base router 2. The bandwidth increase session establishing unit 442 receives an instruction from the management server 5 and once disconnects the session with the detour destination base router, then the total bandwidth of the used bandwidth before disconnection and the used bandwidth requested by the detour source base router To reestablish the session with the detour base router. The bandwidth reduction session establishment unit 443 receives an instruction from the management server 5 and once disconnects the session with the detour destination base router, and then subtracts the use bandwidth of the detour source base router from the pre-disconnection used bandwidth. Re-establish the session with the detour base router. The reconnection establishment unit 444 establishes a session with the detour source base router that has disconnected the session with the detour destination base router. The disconnection unit 445 receives a disconnection request from the detour destination base router and disconnects the session.

  FIG. 4 is a functional block diagram showing the internal configuration of the management server 5. In FIG. 2, the management server 5 includes a communication interface unit 52, a session instruction unit 54, and a storage unit 56.

  The communication interface unit 52 transmits and receives data via the network N. The session instruction unit 54 instructs the center router 4 and the base router 2 to perform session control. The storage unit 56 bypasses the upper limit used bandwidth allocated to each site, the number of sessions currently established between the center and each site, the currently used bandwidth of each session, and the used bandwidth of each session. Information on the used bandwidth of the original base and the detour destination, the distance between the bases, and the charge information according to the used bandwidth is stored.

The session instruction unit 54 includes a connection instruction unit 541, a connection destination selection unit 542, a reconnection instruction unit 543, a session management unit 544, and a detour destination disconnection instruction unit 545.
The connection instruction unit 541 receives a connection request from the base router 2, and if the number of sessions currently established by the center router 4 does not exceed the upper limit, the connection instruction unit 541 sends a connection instruction to the base router 2 of the connection request transmission source. If it exceeds, the address of the detour destination base router is transmitted to the base router 2 of the connection request transmission source. The connection destination selection unit 542 selects the detour destination base router based on the free bandwidth obtained from the information stored in the storage unit 56, the distance between the bases, and the charge according to the used bandwidth. The reconnection instruction unit 543 instructs the center router 4 to reconnect in order to change the bandwidth used for each session. The session management unit 544 manages a session established with the base router 2 at each base and its used bandwidth. The detour destination disconnection instruction unit 545 receives a notification that the detour destination base router has disconnected the session with the center router 4 and instructs the detour source base router to disconnect from the detour destination base router.

FIG. 5 is a diagram illustrating a configuration example of the routing setting information stored in the storage unit 26 of the base router 2 and the storage unit 46 of the center router 4.
In the present embodiment, IPsec is applied to transmission data between the base router 2 and the center router 4 and between the base routers 2 at different bases. In IPsec, an IP packet is encapsulated, and a new IP header is added to the encapsulated IP packet. Hereinafter, an IP packet generated by adding an IP header to an encapsulated IP packet is referred to as an “IPsec packet”. Generally, since an IP packet encapsulated in an IPsec packet is encrypted, decryption is performed when decapsulation is performed by releasing the encapsulation from the IPsec packet and acquiring the IP packet. The key used for encryption and decryption is generated and updated by communication between nodes where the IPsec tunnel is established.

As shown in the figure, the routing setting information includes the IPsec packet, that is, the destination IP address of the transmission data, the source IP address, the destination local address of the IP packet encapsulated in the IPsec packet, and the source. It consists of a record in which a local address is associated with an IPsec identifier.
In the present embodiment, an object encapsulated in an IPsec packet is an IP packet in which data transmitted and received between the terminal 1 and the service providing server 6 is set. Therefore, the local address of the terminal 1 or the local address of the service providing server 6 is set as the transmission destination / source address of the encapsulated IP packet. On the other hand, the destination IP address and the outgoing IP address set in the IPsec packet are the NGN IP addresses of the base router 2 and the center router 4 that have established the IPsec tunnel.
The source local address may be omitted. In this case, whether or not the packet is an IPsec target is determined based only on the destination local address of the IP packet to be encapsulated.

FIG. 6 is a diagram illustrating a configuration example of a connection base management table stored in the storage unit 56 of the management server 5.
In the figure, each record in the connection base management table corresponds to one session, and the number of records in the connection base management table represents the number of currently connected sessions managed by the management server 5. Each record of the connection base management table includes a connection source of a currently established session, a connection destination, a detour connection connection source indicating a detour source establishing a session with the connection source as a detour destination, and an upper limit of the session Information that associates the upper limit bandwidth indicating the used bandwidth, the connection bandwidth that is used by the connection source, the detour connection bandwidth that is used by the detour connection connection source, and the total connection bandwidth of the session Consists of. Since multiple detour sources may bypass one detour destination, multiple pairs of detour connection connection sources and detour connection bands are included, and the used bandwidth requested by detour connection connection source (i) is detour connection. Band (i) (i is an integer of 1 or more).
In the first record of the figure, the upper limit bandwidth of data communication is “15 [Mbps]” for the session in which the connection source is the base router 2a with the “base A” and the connection destination is the “center”. This indicates that the connection bandwidth “10 [Mbps]” is requested from the connection source base router 2 a and the session is established, and the total connection bandwidth “10 [Mbps]” is currently used. In addition, the detour connection connection source and the detour connection band are not set, and it is indicated that there is no other base router 2 that is currently connected with the base router 2a of the connection source “base A” as a detour destination.

  FIG. 7 is a diagram illustrating a configuration example of a fee management table stored in the storage unit 56 of the management server 5. As shown in the figure, the fee management table is made up of records in which the bandwidth used for data communication is associated with the fee.

  FIG. 8 is a diagram illustrating a configuration example of the inter-base distance management table stored in the storage unit 56 of the management server 5. The inter-base distance management table is a table indicating the distance between bases. In the figure, a case where there are bases A to C is shown, and a unit of distance is omitted.

Next, the operation of the traffic detour system will be described.
Here, the case where the detour destination base router is the base router 2 of the base A and the detour source base router is the base router 2 of the base B will be described as an example.
Further, the NGN IP address of the center router 4 of the service center is “1.1.1.1”, the NGN IP address of the management server 5 is “1.1.1.2”, and the local address of the service providing server 6 is “ 10.1.1.1 ”, the local address of the terminal 1a at the base A is“ 10.1.3.3.1 ”, the NGN IP address of the base router 2a is“ 1.1.1.3 ”, and the base B The local address of the terminal 1b is “10.1.1.4.1”, and the NGN IP address of the base router 2b is “1.1.1.4”.

In addition, the SIP message name corresponding to the signal name is described in []. However, in the case of a unique SIP message not defined in the standard, it is described as [Unique message]. In addition, a parameter related to the SIP session is described as (for SIP), and a parameter related to data communication is described as (for data communication).
Note that the SIP [200 OK] message is a response indicating that the processing for the request has been successful, and is returned upon successful processing, regardless of the type of request.

9 and 10 are diagrams illustrating a detour control sequence.
First, in FIG. 9, when the base router 2a at the base A receives a connection request from the terminal 1a, or when a command for instructing establishment of a session is input to the base router 2a, the connection request unit 241a A connection request [unique message] is transmitted with the line number as the destination (step S110). In the connection request, the line number of the site A (for SIP), the communication type of the site A (for SIP), and the bandwidth used by the site A (for SIP) are set. Since the connection request can use the same parameters as the SIP INVITE message, the NGN address (for data communication) of the base router 2a and the communication type (for data communication) of the base router 2a can be set. The SIP server 3 converts the line number of the service center set as the destination of the connection request into the real IP address of the management server 5 and transmits it (step S115).

  The connection instruction unit 541 of the management server 5 acquires the number of records in the connection site management table stored in the storage unit 56 as the current number of established sessions with each site, and adds 1 to the current number of established sessions. When the number of sessions is less than or equal to a predetermined upper limit for the center line, it is determined that connection is possible. When it is determined that connection is possible, the connection instruction unit 541 transmits a connection instruction with the base A to the center router 4 (step S120). In this connection instruction, the line number, the communication type, and the use band of the base A set in the connection request received in step S115 are set.

  When the connection establishment unit 441 of the center router 4 receives the connection instruction with the base A from the management server 5, the call establishment request [INVITE] is transmitted with the line number of the base A as the destination (step S125). In the call connection request, the service center line number (for SIP), the communication type of base A (for SIP), the bandwidth used at base A (for SIP), the NGN IP address of the center router 4 (for data communication), and The communication type (for data communication) of the center router 4 is set. The line number, the communication type, and the used bandwidth of the site A are acquired from the connection instruction with the site A received from the management server 5. The SIP server 3 converts the line number of the base A set as the destination of the call connection request into the NGN IP address of the base router 2a and transmits it (step S130).

  Note that the SIP server 3 relays all SIP messages by converting the destination line number set in the SIP message into an NGN IP address that is a real address. The description is omitted. The SIP server 3 converts the line number of the base A into the NGN IP address of the base router 2a, and converts the line number of the base B into the NGN IP address of the base router 2b. Further, the line number of the service center is converted into the NGN IP address of the center router 4, but in the case of a unique message, it is converted into the NGN IP address of the management server 5.

  When receiving the call connection request from the center router 4, the connection request unit 241a of the base router 2a returns a connection response [200 OK] with the line number of the service center as the destination (steps S135 and S140). In the connection response, the NGN IP address (for data communication) of the base router 2a and the communication type (for data communication) of the base router 2a are set. The connection establishment unit 441 of the center router 4 receives the connection response from the base router 2a, and returns a reception confirmation [ACK] (steps S145 and S150).

  When the connection request unit 241a of the base router 2a receives the reception confirmation from the center router 4, an IPsec tunnel is established between the base router 2a and the center router 4 (step S155). The data communication control unit 28a of the base router 2a adjusts parameters such as encryption / authentication algorithm to be used in accordance with the IPsec standard protocol with the data communication control unit 48 of the center router 4. Thereby, the data communication control unit 28a of the base router 2a transmits the local address of the terminal 1a, which is stored in advance or acquired from the connection request received from the terminal 1a, to the center router 4 and controls the data communication of the center router 4. The unit 48 transmits the local address of the service providing server 6 stored in advance to the base router 2a. The data communication control unit 28a of the base router 2a updates the routing setting information in the storage unit 26a, and the data communication control unit 48 of the center router 4 updates the routing setting information in the storage unit 46.

FIG. 13 is a diagram showing the setting contents of the routing setting information in step S155. FIG. 13A shows the setting contents of the routing setting information stored in the base router 2 a, and FIG. 13B shows the setting contents of the routing setting information stored in the center router 4.
As shown in FIG. 13A, when the data communication control unit 28a of the base router 2a adds a record to the routing setting information, the center router acquired from the call connection request received in step S130 as the destination IP address of the transmission data 4 and the NGN IP address “1.1.1.3” of the base router 2a set in the connection response transmitted in step S135 as the outgoing IP address of the transmission data. The local address “10.1.1.1” of the service providing server 6 received from the data communication control unit 48 of the center router 4 is set as the destination local address, and the local address “10.1” of the terminal 1a is set as the source local address. .. 3.1 "is set. Also, the assigned “100” is set in the IPsec identifier.
On the other hand, as shown in FIG. 13B, when the data communication control unit 48 of the center router 4 adds a record to the routing setting information, the base acquired from the connection response received in step S140 to the destination IP address of the transmission data The NGN IP address “1.1.1.1” of the center router 4 set in the call connection request transmitted in step S125 to the outgoing IP address of the transmission data is the NGN IP address “1.1.1.3” of the router 2a. ”As the transmission destination local address and the local address“ 10.1.3.3.1 ”of the terminal 1a received from the data communication control unit 28a as the transmission destination local address, and the local address“ 10.3.1 ”of the service providing server 6 as the transmission source local address. "1.1.1" is set. Also, the assigned “100” is set in the IPsec identifier.

  In FIG. 9, the connection establishment unit 441 of the center router 4 transmits a connection completion notification with the base A to the management server 5 (step S160). When the session management unit 544 of the management server 5 receives the connection completion notification with the site A, the session management unit 544 updates the connection site management table. The setting contents of the connection base management table after the update are as shown in FIG. Specifically, first, the session management unit 544 of the management server 5 reads the upper limit connection band of the site A from the storage unit 56 and adds a record to the connection site management table stored in the storage unit 56. Then, the connection source “base A” and the connection destination “center” are written in the added record, and the upper limit use band “15 [Mbps]” of the base A read out from the storage unit 56 is added to the upper limit band. In addition, the used bandwidth “10 [Mbps]” set in the connection instruction with the base A transmitted in step S120 is written in the total bandwidth.

  In FIG. 9, data communication using the IPsec tunnel established in step S155 is performed between the terminal 1a and the service providing server 6 (step S165). That is, the terminal 1a sets the local IP address “10.1.1.1” of the service providing server 6 as the destination IP address and sets the IP address “10.1.3.3.1” of the terminal 1a as the source IP address. Send transmission data. The data communication control unit 28a of the base router 2a searches the routing setting information stored in the storage unit 26a, and the information in the transmission destination local address and transmission source local address fields is set in the transmission data received from the terminal 1a. A record that matches the current destination IP address and the source IP address is detected. The data communication control unit 28a encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the transmission IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address, a source IP address, and an IPsec identifier are added and transmitted. As a result, the NGN IP address “1.1.1.1” of the center router 4 is set as the destination IP address, the NGN IP address “1.1.1.3” of the base router 2 a is set as the IPsec identifier as the source IP address. “100” is set and transmitted to the center router 4. The data communication control unit 48 of the center router 4 decapsulates transmission data from the received IPsec packet and transmits it. As a result, the transmission data is routed to the service providing server 6.

  On the other hand, the service providing server 6 sets the local IP address “10.1.3.3.1” of the terminal 1a as the destination IP address, and the IP address “10.1.1.1.1” of the service providing server 6 as the source IP address. Send the set transmission data. The data communication control unit 48 of the center router 4 searches the routing setting information stored in the storage unit 46, and information in the transmission destination local address and transmission source local address fields is included in the transmission data received from the service providing server 6. A record that matches the set destination IP address and source IP address is detected. The data communication control unit 48 encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the source IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address, a source IP address, and an IPsec identifier are added and transmitted. Thereby, the NGN IP address “1.1.1.3” of the base router 2a is set as the destination IP address, the NGN IP address “1.1.1.1” of the center router 4 is set as the IPsec identifier as the source IP address. “100” is set and transmitted to the base router 2a. The data communication control unit 28a of the base router 2a decapsulates transmission data from the received IPsec packet and transmits it. As a result, the transmission data is routed to the terminal 1a.

  In FIG. 10, data communication is performed between the terminal 1a at the site A and the service providing server 6 at the service center using the session established by the procedure shown in FIG. 9 (step S210). At this time, when the base router 2b of the base B receives a connection request from the terminal 1b or receives a command instructing establishment of a session with the center router 4, the connection request unit 241b A connection request [unique message] is transmitted with the line number as the destination (steps S215 and S220). The connection request includes the line number of the base B (for SIP), the communication type of the base B (for SIP), the bandwidth used by the base B (for SIP), the NGN address of the base router 2b (for data communication), and the base router The communication type 2b (for data communication) is set.

  When receiving the connection request from the base router 2b, the connection instruction unit 541 of the management server 5 acquires the number of records in the connection base management table stored in the storage unit 56 as the current number of established sessions with each base. If the number of sessions obtained by adding 1 to the number of established sessions exceeds the upper limit predetermined for the center line, it is determined that detouring is necessary. When the connection instruction unit 541 determines that detouring is necessary, the connection destination selection unit 542 refers to the connection site management table stored in the storage unit 56 and establishes a site where the connection bandwidth is not 0, that is, the current session is established. The base in the center is determined as the detour base. When there are a plurality of bases whose connection bandwidth is not 0, the connection destination selection unit 542 selects one from the specified bases. Although the selection procedure will be described later, a case where the site A is selected as a detour destination will be described as an example (step S225).

  The connection instruction unit 541 of the management server 5 returns a connection request response [unique message] instructing detour to the base A that is the detour destination selected by the connection destination selection unit 542 with the line number of the base B as the destination ( Steps S230 and S235). The line number (for SIP) of the site A is set in the connection request response.

  Upon receiving the connection request response from the management server 5, the connection request unit 241b of the base router 2b transmits a call connection request [INVITE] with the line number of the base A set in the connection request response as the destination (step S240). , S245). In the call connection request, the line number of the base B (for SIP), the communication type of the base B (for SIP), the use band of the base B (for SIP), the NGN IP address of the base router 2b (for data communication), and The communication type (for data communication) of the base router 2b is set. The used bandwidth is the same as the used bandwidth in the connection request transmitted in step S215.

  When the detour session establishment unit 246a of the base router 2a receives the call connection request from the base router 2b, it returns a connection response [200OK] with the line number of the base B as the destination (steps S250 and S255). In the connection response, the NGN IP address (for data communication) of the base router 2a and the communication type (for data communication) of the base router 2a are set. When receiving the connection response, the connection request unit 241b of the base router 2b returns an acknowledgment [ACK] (steps S260 and S265).

  On the other hand, the reconnection instruction unit 543 of the management server 5 transmits a reconnection instruction with the base A to the center router 4 (step S280). Note that the transmission of the connection request in step S230 and the transmission of the reconnection instruction in step S280 are performed asynchronously. In the reconnection instruction transmitted in step S280, the line number, the communication type, the use band, and the line number of the base B selected as the detour destination connection base are set. The used bandwidth is the connection bandwidth read from the record of the connection location management table (FIG. 6) in which the connection source “site A” and the connection destination “center” are set, and the location bandwidth received from the location router 2b in location B in step S220. This is a band obtained by adding the used band set in the connection request. At the same time, the session management unit 544 reserves a session until a connection completion notification with the base A is received for reconnection with the base A. In the reconnection procedure with the base A, first, the session with the base A is temporarily disconnected (steps S285 to S300 to be described later), and then the session with the use band instructed by the reconnection instruction with the base A is performed. This is because the connection is not permitted even if a connection request is received from an unintended base router 2 while the session is temporarily disconnected. Therefore, even during the temporary disconnection of the session, the record where the site A is the connection source is not deleted from the connection site management table, and the number of established sessions is maintained. When the management server 5 receives a connection request from the base router 2 at another base while the session is being reserved, the connection instruction unit 541 returns [400Error] or the like.

  When the bandwidth increase session establishing unit 442 of the center router 4 receives the reconnection instruction with the base A from the management server 5, it transmits a disconnection request [BYE] with the line number of the base A as the destination (steps S285 and S290). In the disconnection request, the line number of the detour base B is set as a unique parameter. When receiving the disconnection request from the center router 4, the center instruction disconnecting unit 247a of the base router 2a returns a disconnection response [200OK] (steps S295 and S300).

  Upon receiving the disconnection response from the base router 2a, the band increase session establishing unit 442 of the center router 4 transmits a call connection request [INVITE] with the line number of the base A as the destination (steps 305 and S310). The call connection request includes a service center line number (for SIP), a service center communication type (for SIP), a service center bandwidth (for SIP), an NGN IP address of the center router 4 (for data communication), and The communication type (for data communication) of the center router 4 is set. The use band of the service center is the use band set in the reconnection instruction with the base A received from the management server 5 in step S280.

  Upon receiving the call connection request from the center router 4, the bandwidth increase reconnection unit 248a of the base router 2a returns a connection response [200OK] (steps S315 and S320). In the connection response, the NGN IP address of the base router 2a (for data communication) and the communication type (for data communication) of the base router 2a are set. When the bandwidth increasing session establishing unit 442 of the center router 4 receives the connection response from the base router 2a, it returns an acknowledgment [ACK] (steps S325 and S330).

  When the bandwidth increase reconnection unit 248a of the base router 2a receives the reception confirmation from the center router 4, an IPsec tunnel is established between the base router 2a and the center router 4 according to the IPsec standard protocol (step S335). Further, the bypass session establishment unit 246a of the base router 2a establishes an IPsec tunnel between the base router 2a and the base router 2b according to the IPsec standard protocol (step S340).

  The data communication control unit 48 of the center router 4 transmits the local address of the service providing server 6 to the base router 2a, and the data communication control unit 28b of the base router 2b transmits the local address of the terminal 1b to the base router 2a. The detour session establishment unit 246a of the base router 2a determines that the base router 2b is the detour source base from the detour source line number set in the disconnection request received in step S290. Therefore, the data communication control unit 28a of the base router 2a transmits the local address of the service providing server 6 received from the center router 4 to the detour source base router 2b, and the local address of the terminal 1b received from the base router 2b is the center address. Transmit to router 4. As a result, the data communication control unit 28a of the base router 2a receives the routing setting information of the storage unit 26a, the data communication control unit 28b of the base router 2b receives the routing setting information of the storage unit 26b, and the data communication control of the center router 4. The unit 48 updates the routing setting information in the storage unit 46.

FIG. 14 is a diagram showing the setting contents of the routing setting information set in steps S335 and S340. 14A shows the setting contents of the routing setting information stored in the base router 2a, FIG. 14B shows the setting contents of the routing setting information stored in the center router 4, and FIG. The setting contents of the routing setting information stored in the base router 2b are shown.
As shown in FIG. 14A, a detour record is added to the routing setting information of the base router 2a shown in FIG. Specifically, among the records shown in FIG. 13A, a record in which contents other than the source local address are copied is added, and the source local address is received from the data communication control unit 28b of the base router 2b. The local address “10.1.1.4.1” of the terminal 1b is set.
Further, the data communication control unit 28a of the base router 2a replaces the transmission destination local address and the transmission source local address of the added record, and further, records that replace the transmission data destination IP address and the transmission data source IP address. Further, “200” assigned to the IPsec identifier is set.

  Further, as shown in FIG. 14B, a record for data communication between the terminal 1b at the base B and the service providing server 6 is added to the routing setting information of the center router 4 shown in FIG. 13B. The Specifically, when the data communication control unit 48 of the center router 4 adds a record to the routing setting information, the NGN IP address “of the base router 2a obtained from the connection response received in step S320 is added to the destination IP address of the transmission data. "1.1.1.3" is set to the outgoing IP address of the transmission data, and the NGN IP address "1.1.1.1" of the center router 4 set in the call connection request transmitted in step S305 is the destination local address. The local address “10.1.1.4.1” of the terminal 1b received from the base router 2a is set, and the local address “10.1.1.1” of the service providing server 6 is set as the source local address. Also, “100” assigned to the IPsec tunnel with the base A is set in the IPsec identifier.

  On the other hand, the data communication control unit 28b of the base router 2b also adds a new record to the routing setting information. Then, as shown in FIG. 14C, the NGN IP address “1.1.1.3” of the base router 2a acquired from the connection response received in step S255 is set to the destination IP address of the transmission data. The service received from the data communication control unit 28a of the base router 2a as the destination local address and the NGN IP address “1.1.1.4” of the base router 2b set in the connection request transmitted in step S240 as the source IP address The local address “10.1.1.1” of the providing server 6 is set, and the local address “10.1.4.1” of the terminal 1b is set as the source local address. Further, “200” assigned to the IPsec tunnel with the base A is set in the IPsec identifier.

  In FIG. 10, the bandwidth increase session establishment unit 442 of the center router 4 transmits a connection completion notification with the base A to the management server 5 (step S345). When the session management unit 544 of the management server 5 receives the connection completion notification with the site A, the session management unit 544 updates the connection site management table. FIG. 15 is a diagram showing the setting contents of the updated connection base management table. The session management unit 544 identifies the connection site management table in which the connection source “location A” and the connection destination “center” are set, and detours “location B” as the detour connection connection source (1) of the identified record. The use band “2 [Mbps]” set in the connection request received from the base router 2b of the base B in step S220 is written in the connection band (1). Further, the session management unit 544 sets the total connection bandwidth of the identified record to the use band set in the connection instruction with the base A transmitted in step S280, that is, the current total connection bandwidth “10 [Mbps]” to the base B To the total bandwidth “12 [Mbps]” obtained by adding “2 [Mbps]” to the detour connection bandwidth (detour connection bandwidth (1)).

Through the above procedure, the IPsec tunnel is re-established between the base router 2a and the center router 4, and data communication is performed between the terminal 1a and the service providing server 6, and between the terminal 1b and the service providing server 6. (Steps S350 and S355).
Data communication between the terminal 1a and the service providing server 6 is performed in the same manner as in step S165 of FIG.

  On the other hand, data communication between the terminal 1b and the service providing server 6 is performed as follows. That is, the terminal 1b sets the local IP address “10.1.1.1” of the service providing server 6 as the destination IP address and the IP address “10.1.1.4.1” of the terminal 1b as the source IP address. Send transmission data. The data communication control unit 28b of the base router 2b searches the routing setting information stored in the storage unit 26b, and the information in the transmission destination local address and transmission source local address fields is set in the transmission data received from the terminal 1b. A record that matches the current destination IP address and the source IP address is detected. The data communication control unit 28b encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the transmission IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address and a sender IP address are added and transmitted. Thus, in the IPsec packet encapsulating the transmission data, the NGN IP address “1.1.1.3” of the base router 2a is set as the destination IP address, and the NGN IP address “1.1” of the base router 2b is set as the source IP address. .1.4 "and IPsec identifier" 200 "are set and transmitted to the base router 2a.

The data communication control unit 28a of the base router 2a decapsulates the transmission data encapsulated in the IPsec packet received from the terminal 1b. The data communication control unit 28a retrieves the routing setting information stored in the storage unit 26a, and the information of the transmission destination local address and the transmission source local address column is the destination IP address set in the decapsulated transmission data and A record that matches the source IP address is detected. The data communication control unit 28a encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the transmission IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address, a source IP address, and an IPsec identifier are added and transmitted. As a result, the NGN IP address “1.1.1.1” of the center router 4 is set as the destination IP address, the NGN IP address “1.1.1.3” of the base router 2 a is set as the IPsec identifier as the source IP address. “100” is set and transmitted.
The data communication control unit 48 of the center router 4 decapsulates transmission data from the received IPsec packet and transmits it. As a result, the transmission data is routed to the service providing server 6.

  Further, the service providing server 6 sets the local IP address “10.1.1.4” of the terminal 1b as the destination IP address, and the IP address “10.1.1.1” of the service providing server 6 as the source IP address. Send the set transmission data. The data communication control unit 48 of the center router 4 searches the routing setting information stored in the storage unit 46, and information in the transmission destination local address and transmission source local address fields is included in the transmission data received from the service providing server 6. A record that matches the set destination IP address and source IP address is detected. The data communication control unit 48 encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the source IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address, a source IP address, and an IPsec identifier are added and transmitted. Thereby, the NGN IP address “1.1.1.3” of the base router 2a is set as the destination IP address, the NGN IP address “1.1.1.1” of the center router 4 is set as the IPsec identifier as the source IP address. “100” is set and transmitted.

The data communication control unit 28a of the base router 2a decapsulates the transmission data encapsulated in the IPsec packet received from the center router 4. The data communication control unit 28a retrieves the routing setting information stored in the storage unit 26a, and the information of the transmission destination local address and the transmission source local address column is the destination IP address set in the decapsulated transmission data and A record that matches the source IP address is detected. The data communication control unit 28a encapsulates the received transmission data into an IPsec packet based on the destination IP address of the transmission data and the transmission IP address of the transmission data in the detected record, and the destination read from the detected routing setting information record An IP address, a source IP address, and an IPsec identifier are added and transmitted. As a result, the NGN IP address “1.1.1.4” of the base router 2b is set as the destination IP address, and the NGN IP address “1.1.1.3” of the base router 2a is set as the IPsec identifier as the source IP address. “200” is set and transmitted.
The data communication control unit 28b of the base router 2b decapsulates and transmits the transmission data encapsulated in the IPsec packet received from the base router 2a. As a result, the transmission data is routed to the terminal 1b.

Next, the site selection procedure in step S225 will be described.
First, the connection destination selection unit 542 of the management server 5 refers to the connection base management table, and specifies a base whose connection bandwidth is not 0 as the first selection candidate base. When there is one first selection candidate base, the first selection candidate base is determined as a detour destination base.

  When there are a plurality of first selection site candidates, the connection destination selection unit 542 selects the first selection candidate site whose free bandwidth obtained by subtracting the connection bandwidth from the upper limit bandwidth is greater than or equal to the use bandwidth set in the received connection request. Identifies as a selected site candidate. If there is no second selection candidate base, the base with the most free bandwidth is selected as the detour destination base from the first selection candidate bases.

  On the other hand, when there is one second selection candidate site, the connection destination selection unit 542 determines the identified second selection candidate site as a detour destination site, and when there are a plurality of second selection candidate sites, the second selection candidate A base is selected from the bases according to the following conditions (1) and (2). It is possible to arbitrarily set whether to use both of the conditions (1) and (2), or to use one of them, and when to use both of the conditions (1) and (2).

(1) A charge corresponding to a band obtained by adding the connection band of the second selection candidate base and the use band set in the connection request received from the detour source base router is read from the charge management table, and the read charge is The cheapest second selection candidate base is selected. Thereby, it is possible to select a detour destination base where the charge is optimal.
(2) From the inter-base distance management table, the distance between the second selection candidate base and the base to which the detour source base router that is the transmission source of the connection request belongs is read, and the second selection candidate base with the closest read distance is selected. To do. Thereby, it is possible to reduce the delay and suppress the increase in traffic in the network N as much as possible.

  If the available bandwidth of the detour base is less than the used bandwidth set in the received connection request, the available bandwidth is set in the connection request response in step S230. In this case, the base router 2 that has received the connection request response sets the available bandwidth set in the connection request response as the use bandwidth of the call connection request to be transmitted to the detour destination base router 2.

FIG. 11 shows a case where data communication is performed between the terminal 1a and the service providing server 6 and between the terminal 1b and the service providing server 6 according to the procedure of FIG. 9 and FIG. This is a sequence when communication with the service providing server 6 is completed.
The data communication control unit 28b of the base router 2b of the base B terminates the communication between the terminal 1b and the service providing server 6 when it does not receive a communication packet for a predetermined time or when the IPsec key update times out. It detects (step S410). Thus, the IPsec tunnel is terminated between the data communication control unit 28b of the base router 2b and the data communication control unit 28a of the base router 2a according to the IPsec standard protocol (step S415). The base router 2a deletes the record regarding the IPsec tunnel with the base router 2b from the routing setting information, and the base router 2b deletes the record regarding the IPsec tunnel with the base router 2a from the routing setting information.

  Subsequently, the detour destination disconnection request unit 242 of the base router 2b transmits a disconnection request [BYE] with the line number of the base A as the destination (steps S420 and S425). When the detour source cutting unit 249a of the base router 2a receives the disconnect request from the base router 2b, it returns a disconnect response [200OK] (steps S430 and S435). As a result, the session between the base router 2a and the base router 2b is disconnected.

  When receiving the disconnection response from the base router 2a, the detour destination disconnection notification unit 243b of the base router 2b transmits a disconnection notification [unique message] with the line number of the service center as the destination (steps S440 and S445). When receiving the disconnection notification from the base router 2b, the reconnection instruction unit 543 of the management server 5 returns a disconnection notification response (steps S450 and S455), and further, the base A that is the detour destination connection base of the base B Is sent to the center router 4 (step S460). In this reconnection instruction, the line number of the base A, the communication type, and the use band are set. The use band to be set is the detour connection connection source “base B” from the connection band of the base A read from the record of the connection base management table (FIG. 15) in which the connection source “base A” and the connection destination “center” are set. ”Is the use band obtained by subtracting the detour connection band (detour connection band (1)).

  When the bandwidth reduction session establishing unit 443 of the center router 4 receives the reconnection instruction with the base A from the management server 5, it transmits a disconnection request [BYE] with the line number of the base A as the destination (steps S465 and S470). When receiving the disconnection request from the center router 4, the center instruction disconnecting unit 247a of the base router 2a returns a disconnection response [200OK] (steps S475 and S480).

  When receiving the disconnection response from the base router 2a, the band reduction session establishing unit 443 of the center router 4 transmits a call connection request [INVITE] with the line number of the base A as the destination (steps S485 and S490). The call connection request includes a service center line number (for SIP), a service center communication type (for SIP), a service center bandwidth (for SIP), an NGN IP address of the center router 4 (for data communication), and The communication type (for data communication) of the center router 4 is set. The use band of the service center is the use band set in the reconnection instruction with the base A received from the management server 5 in step S460.

  When receiving the call connection request from the center router 4, the bandwidth reduction reconnection unit 251a of the base router 2a returns a connection response [200OK] (steps S495 and S500). In the connection response, the NGN IP address (for data communication) of the base router 2a and the communication type (for data communication) of the base router 2a are set. When the bandwidth reduction session establishment unit 443 of the center router 4 receives the connection response from the base router 2a, it returns an acknowledgment [ACK] (steps S505 and S510).

  When the bandwidth reduction reconnection unit 251a of the base router 2a receives the reception confirmation from the center router 4, the base router 2a and the center router 4 follow the same protocol as in step S155 of FIG. An IPsec tunnel is established (step S515). Thereby, the routing setting information of the base router 2a is set similarly to FIG. 13A, and the routing setting information of the center router 4 is set similarly to FIG. 13B. However, the IPsec identifier may be a newly assigned value.

  Further, the bandwidth reduction session establishing unit 443 of the center router 4 transmits a connection completion notification with the base A to the management server 5 (step S520). When the session management unit 544 of the management server 5 receives the connection completion notification with the site A, the session management unit 544 updates the connection site management table. FIG. 16 is a diagram showing the setting contents of the updated connection base management table. The session management unit 544 identifies the record of the connection base management table in which the connection source “base A” and the connection destination “center” are set, and the total connection bandwidth set in the specified record is the current total connection Rewrite the band “12 [Mbps]” to “10 [Mbps]” by subtracting the “2 [Mbps]” detour connection band (the detour connection band (1)) of the detour connection connection source “base B”, and the detour connection. The setting values of the connection source “base B” (detour connection connection source (1)) and the detour connection band (detour connection band (1)) are deleted.

  Data communication using the IPsec tunnel established in step S515 is performed between the terminal 1a and the service providing server 6 by the same procedure as in step S165 of FIG. 9 (step S525).

FIG. 12 shows a case where data communication is performed between the terminal 1a and the service providing server 6 and between the terminal 1b and the service providing server 6 according to the procedure of FIG. 9 and FIG. This is a sequence when communication with the service providing server 6 is completed.
The data communication control unit 28a of the base router 2a of the base A detects the end of communication between the terminal 1a and the service providing server 6 (step S610). The IPsec tunnel is terminated between the data communication control unit 28a of the base router 2a and the data communication control unit 48 of the center router 4 in accordance with an IPsec standard protocol (step S615). The base router 2a deletes the record regarding the IPsec tunnel with the center router 4 from the routing setting information, and the center router 4 deletes the record regarding the IPsec tunnel with the base router 2a from the routing setting information.

  Subsequently, the disconnection request unit 250a of the base router 2a transmits a disconnection request [BYE] with the line number of the service center as the destination (steps S620 and S625). When receiving the disconnection request from the base router 2a, the disconnecting unit 445 of the center router 4 returns a disconnection response [200OK] (steps S630 and S635). As a result, the session between the base router 2a and the center router 4 is disconnected.

  The disconnecting unit 445 of the center router 4 notifies the management server 5 of disconnection from the base A (step S637). The session management unit 544 of the management server 5 identifies a record in the connection base management table in which the connection source “base A” and the connection destination “center” are set. Since the detour connection connection source and the detour connection band are set in the specified record, the session management unit 544 does not delete the specified record, and the current total connection band “12 [Mbps]” The connection band “10 [Mbps]” of “A” is rewritten to “2 [Mbps]”, and the connection band is rewritten to “0”. The detour destination disconnection instruction unit 545 of the management server 5 transmits a connection disconnection request [unique message] with the line number of the base B that is the detour source of the base A as the destination (steps S640 and S645).

  When receiving the connection disconnection request from the management server 5, the detour destination cutting unit 244b of the base router 2b transmits a disconnect request [BYE] with the line number of the base A as the detour destination as the destination (steps S650 and S655). When receiving the disconnection request from the base router 2b, the detour source disconnection unit 249a of the base router 2a returns a disconnection response [200OK] (steps S660 and S665). As a result, the session between the base router 2a and the base router 2b is disconnected.

  When the detour destination cutting unit 244b of the base router 2b receives the disconnection response from the base router 2a, the data communication control unit 28b communicates with the data communication control unit 28a of the base router 2a in accordance with the IPsec standard protocol. The tunnel is terminated (step S670). The base router 2a deletes the record regarding the IPsec tunnel with the base router 2b from the routing setting information, and the base router 2b deletes the record regarding the IPsec tunnel with the base router 2a from the routing setting information.

  Subsequently, the detour destination cutting unit 244b of the base router 2b transmits a connection disconnection request response [unique message] with the line number of the service center as the destination (steps S675 and S680). When receiving the connection disconnection request response from the base router 2b, the reconnection instruction unit 543 of the management server 5 transmits a reconnection instruction to the base B to the center router 4 (step S685). In this reconnection instruction, the line number of B, the communication type, and the bandwidth used are set. The use band is the use band set in the connection request received in step S220 of FIG.

  When the reconnection establishment unit 444 of the center router 4 receives the reconnection instruction with the base B from the management server 5, the call connection request [INVITE] is transmitted with the line number of the base B as the destination (steps S690 and S695). The call connection request includes a service center line number (for SIP), a service center communication type (for SIP), a service center bandwidth (for SIP), an NGN IP address of the center router 4 (for data communication), and The communication type (for data communication) of the center router 4 is set. The use band of the service center is the use band included in the reconnection instruction with the base B received from the management server 5 in step S685.

  When receiving the call connection request from the center router 4, the reconnection unit 245b of the base router 2b returns a connection response [200OK] (steps S700 and S705). In the connection response, the NGN IP address (for data communication) of the base router 2b and the communication type (for data communication) of the base router 2b are set. Upon receiving the connection response from the base router 2b, the reconnection establishment unit 444 of the center router 4 returns an acknowledgment [ACK] (steps S710 and S715).

  When the reconnection unit 245b of the base router 2b receives the reception confirmation from the center router 4, the data communication control unit 28b communicates with the data communication control unit 48 of the center router 4 according to the standard protocol of IPsec. An IPsec tunnel is established between 2b and the center router 4 (step S720). Thereby, the data communication control unit 28a of the base router 2a updates the routing setting information in the storage unit 26a, and the data communication control unit 48 of the center router 4 updates the routing setting information in the storage unit 46.

Specifically, the data communication control unit 28b of the base router 2b adds a record to the routing setting information, and sets the NGN of the center router 4 set in the call connection request received in step S695 to the destination IP address of the transmission data. The NGN IP address “1.1.1.4” of the base router 2b set in the connection response transmitted in step S700 as the IP address “1.1.1.1” as the source IP address of the transmission data, and the destination The local address “10.1.1.1” of the service providing server 6 received from the data communication control unit 48 of the center router 4 is set as the local address, and the local address “10.1.4. 1 ”is set. Also, the assigned IPsec identifier is set.
Further, the data communication control unit 48 of the center router 4 adds a record to the routing setting information, and sets the NGN IP address “1” of the base router 2b set in the connection response received in step S705 as the destination IP address of the transmission data. .1.1.3 ”is set as the source IP address of the transmission data, and the NGN IP address“ 1.1.1.1 ”of the center router 4 set in the call connection request transmitted in step S690 is set as the destination local address. The local address “10.1.4.1” of the terminal 1b received from the base router 2b is set, and the local address “10.1.1.1” of the service providing server 6 is set as the source local address. Further, the same IPsec identifier as that of the base router 2b is set.

  Further, the reconnection establishment unit 444 of the center router 4 transmits a connection completion notification with the base B to the management server 5 (step S725). When the session management unit 544 of the management server 5 receives the connection completion notification with the site B, the session management unit 544 updates the connection site management table. FIG. 17 is a diagram showing the setting contents of the updated connection base management table. The session management unit 544 identifies the record of the connection base management table in which the connection source “base A” and the connection destination “center” are set, bypasses the connection band with the connection source of the specified record as “base B” Rewrite to the detour connection band (detour connection band (1)) “2 [Mbps]” of the connection connection source “base B”, and further detour connection connection source “base B” (detour connection connection source (1)) and its detour The setting value of the connection band (the bypass connection band (1)) is deleted.

  By the above procedure, data communication using the IPsec tunnel established in step S720 is performed between the terminal 1b and the service providing server 6 (step S730).

FIG. 18 is a description example of a connection request [unique message] transmitted from the base router 2b of the base B in step S215 of FIG.
A standard format is used for the SIP tag of the connection request. The description “MESSAGE tel: 0311112222 SIP / 2.0” of the symbol L11 and the description “To: sip: 0311112222” of the symbol L12 indicate that the line number of the destination (service center) is “0311112222”. Further, the description “From: sip: 0312345678; tag = 49583” of the code L13 indicates that the line number of the sending (base router 2b) is “0312345678”. The description “Call-ID: asd88asd77a@1.2.3.4” of the code L14 indicates a call identifier and uniquely identifies the session.
The message body has a unique format. The description “Connect request” of the symbol L15 indicates that this SIP message is “connection request”, and the description “c = IN IP4 1.1.1.4” of the symbol L16 indicates an NGN IP address for data communication (for data communication) The description “b = 10” of the symbol L17 indicates the use band, and the description “m = application 5060 TCP” of the symbol L17 indicates the communication type.

FIG. 19 is a description example of a connection request response [unique message] transmitted from the center router 4 of the service center in step S230 of FIG.
A standard format is also used for the SIP tag of the connection request response. The description “MESSAGE tel: 0312345678 SIP / 2.0” in reference L21 and the description “To: sip: 0312345678” in reference L22 indicate that the line number of the destination (base router 2b) is “0312345678”. In addition, the description “From: sip: 0311112222; tag = 49583” of the code L23 indicates that the line number of the sending (center router 4) is “0311112222”. The description “Call-ID: asd88asd77a@1.2.3.4” of the code L24 is a call identifier.
The message body is in a proprietary format. The description “Connect request Ack” of reference L25 indicates that the SIP message is “connection request response”, the description “SIP / 2.0 200OK” of reference L26 indicates a normal response, and the description “to: 0312345678” of reference L27. Indicates the line number of the detour destination base router 2a.

FIG. 20 is a description example of a connection disconnection notification [unique message] transmitted from the base router 2b of the base B in step S440 of FIG.
A standard format is also used for the SIP tag of the disconnection notification. The descriptions of reference characters L31 to L34 are the same as reference characters L11 to L14 of the connection request shown in FIG. The message body has a unique format, and the description “Disconnect inform” of the symbol L35 indicates that the SIP message is “connection disconnection notification”.

FIG. 21 is a description example of a connection disconnection notification response [unique message] transmitted from the center router 4 of the service center in step S450 of FIG.
A standard format is also used for the SIP tag of the connection disconnection notification response. Descriptions of reference signs L41 to L44 are the same as reference signs L21 to L24 of the connection request response shown in FIG. The message body is in a unique format, and the description “Disconnect request Ack” in L45 indicates that this SIP message is “connection disconnection request response”, and the description “SIP / 2.0 200OK” in L46 indicates a normal response. Show.

FIG. 22 is a description example of a connection disconnection request [unique message] transmitted from the center router 4 in step S640 of FIG.
A standard format is also used for the SIP tag of the connection disconnection request. Descriptions of reference signs L51 to L54 are the same as reference signs L11 to L14 of the connection request shown in FIG. The message body is in a unique format, the description “Disconnect request” of the symbol L55 indicates that the SIP message is “connection disconnection request”, and the description “to: 0312345678” of the symbol L56 is the location to be disconnected. The line number of the router 2a is shown.

FIG. 23 is a description example of a connection disconnection request response [unique message] transmitted from the base router 2b of the base B in step S675 of FIG.
A standard format is also used for the SIP tag of the connection disconnection request response. Descriptions of reference numerals L61 to L64 are the same as reference numerals L21 to L24 of the connection request response shown in FIG. The message body is in a unique format, and the description “Disconnect request Ack” in reference L65 indicates that the SIP message is “connection disconnection request response”, and the description “SIP / 2.0 200 OK” in reference L66 indicates a normal response. Show.

According to the embodiment, it is possible to establish a session between a base and a center exceeding the limit of the number of sessions allocated to the physical line without adding a physical line.
In SIP, once the session is established, the media stream port number is set to zero, so that the communication of the media stream can be completed while continuing the session. However, the media stream reduced during the session cannot be deleted. If the media stream is increased or decreased several times, a media stream with a port number of zero remains in the SIP session. Therefore, by temporarily ending the detour destination session, it is possible to cancel a media stream that is not actually used but remains as port 0 and newly establish a media stream that is actually used.

The center router 4 and the management server 5 may be realized in the same device.
In the above description, an example in which a session between one detour source base router and the center router 4 is detoured in one detour destination base router has been described. However, two or more detours are performed in one detour destination base router. The session of the former base router may be bypassed.
For example, when the upper limit bandwidth between the base A and the center is 15 Mbps, and the session between the base router 2a and the center router 4 at the base A is currently established using 10 Mbps, the request is made from the base router 2b at the base B. The 2 Mbps bandwidth and the 1 Mbps bandwidth session requested from the base router 2n at the base N can be simultaneously bypassed by the base router 2a at the base A.

  The terminal 1, the base router 2, the SIP server 3, the center router 4, the management server 5, and the service providing server 6 described above have a computer system therein. The terminal 1, the session control unit 24 and the data communication control unit 28 of the base router 2, the SIP server 3, the session control unit 44 and the data communication control unit 48 of the center router 4, the session instruction unit 54 of the management server 5, and The process of operation of the service providing server 6 is stored in a computer-readable recording medium in the form of a program, and the above-described processing is performed by the computer system reading and executing this program. The computer system here includes a CPU, various memories, an OS, and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

1, 1a, 1b, 1n ... terminal 2, 2a, 2b, 2n ... base router (base communication device)
DESCRIPTION OF SYMBOLS 22 ... Communication interface part 24 ... Session control part 241 ... Connection request part 242 ... Detour destination disconnection request part 243 ... Detour destination disconnection notification part 244 ... Detour destination disconnection part 245 ... Reconnection part 246 ... Detour session establishment part 247 ... Center instruction | indication Disconnection unit 248 ... Band increase reconnection unit 249 ... Detour source disconnection unit 250 ... Disconnection request unit 251 ... Bandwidth decrease reconnection unit 26 ... Storage unit 28 ... Data communication control unit (detour source data communication control unit, detour destination data communication control) Part)
3 ... SIP server 4 ... Center router (center communication device)
42 ... Communication interface unit 44 ... Session control unit 441 ... Connection establishment unit 442 ... Band increase session establishment unit 443 ... Band decrease session establishment unit 444 ... Reconnection establishment unit 445 ... Disconnection unit 46 ... Storage unit 48 ... Data communication control unit ( Center data communication control unit)
5. Management server (center communication device)
52 ... Communication interface unit 54 ... Session instruction unit 541 ... Connection instruction unit 542 ... Connection destination selection unit 543 ... Reconnection instruction unit 544 ... Session management unit 545 ... Detour destination disconnection instruction unit 6 ... Service providing server

Claims (8)

A traffic detour system in which a center communication device to which a service providing device is connected and a plurality of base communication devices to which terminals are connected are connected via a network,
The base communication device of the detour source is
In response to the connection request transmitted to the center communication device, a detour destination communication address is received, a session establishment request is transmitted to the detour destination base communication device specified by the received communication address, and the detour destination A connection request unit for establishing a session with a base communication device of
A detour source data communication control unit that transmits and receives data between the terminal connected to the detour source base communication device and the service providing device using the session established by the connection request unit;
The detour base communication device is:
Receiving a session establishment request from the detour-source base communication device, and establishing a session with the detour-source base communication device;
A center instruction disconnection unit that receives a disconnection request from the center communication device and disconnects the established session with the center communication device;
A bandwidth increase reconnection unit that receives a session establishment request from the center communication device and a use band wider than the disconnected session, and establishes the received session of the use band with the center communication device;
While transmitting and receiving data between the terminal connected to the detour destination base communication device and the service providing device using the session established by the band increase reconnection unit, the detour source base communication A detour destination for relaying data between the terminal connected to the apparatus and the service providing apparatus using the session established by the detour session establishing unit and the session established by the bandwidth increasing reconnection unit A data communication control unit,
The center communication device is
When the connection request is received from the detour source base communication device and the number of connections in the session has reached the upper limit, communication of the detour destination base communication device selected from the base communication devices that have already established a session A connection instruction section for returning an address;
After disconnecting the session with the detour destination base device by transmitting the disconnect request to the detour destination base communication device, a session establishment request to the detour destination base communication device, and the bandwidth higher than before disconnection A bandwidth increase session establishment unit that transmits a use band and establishes a session of the use band transmitted with the detour base communication device;
Data between the terminal connected to the detour base communication device and the service providing device, and data between the terminal connected to the detour base communication device and the service providing device A center data communication control unit that transmits and receives through the session established by the bandwidth increase session establishment unit,
This is a traffic detour system. The connection request unit transmits the requested use band to the base communication device,
The band increase session establishment unit is configured to calculate a total use band of a band used by the disconnected established session and the use band received from the bypass source communication apparatus as the detour destination base communication apparatus. Send to
The traffic detour system according to claim 1, wherein: The center communication device is
A storage unit storing a connection base management table indicating a use bandwidth of an upper limit of a session with the base communication device, and a use bandwidth of the session established with the base communication device;
The base where the free bandwidth obtained by subtracting the used bandwidth of the established session from the upper limit used bandwidth is greater than or equal to the requested used bandwidth received from the detour source base communication device with reference to the connection base management table A connection destination selection unit for selecting a communication device;
The connection instruction unit returns the communication address of the base communication device selected by the connection destination selection unit.
The traffic detour system according to claim 2, wherein: The center communication device is
A charge management table indicating a charge corresponding to the use band, and a storage unit for storing the use band of the session established with the base communication device;
Calculate the total bandwidth of each of the base communication devices read from the storage unit and the requested usage bandwidth received from the detour source base communication device, and correspond to each of the calculated total bandwidths A connection destination selection unit that reads a charge from the charge management table and selects the base communication device with the lowest read charge;
The connection instruction unit returns the communication address of the base communication device selected by the connection destination selection unit.
The traffic detour system according to claim 2, wherein: The center communication device is
A storage unit for storing information on a distance between the base communication devices;
A connection destination selection unit that selects the base communication device that is closest to the detour source base communication device with reference to the storage unit from among the base communication devices that have already established a session;
The connection instruction unit returns the communication address of the base communication device selected by the connection destination selection unit.
The traffic detour system according to claim 1 or 2, characterized in that The detour base communication device is:
A detour destination disconnect request unit that transmits a disconnection request to the detour destination base communication device, and disconnects the session with the detour destination base communication device;
A detour destination disconnect notification unit for notifying the center communication device of disconnection of the detour destination base communication device;
The detour base communication device is:
A detour source cutting unit that receives the disconnection request from the detour source base communication device and disconnects the session with the detour source base communication device;
A bandwidth reduction reconnection unit that receives the session establishment request from the center communication device and a bandwidth that is narrower than the disconnected session, and establishes the received session of the bandwidth to be used with the center communication device. ,
The detour destination data communication control unit transmits and receives data between the terminal connected to the detour destination base communication device and the service providing device using the session established by the bandwidth reduction reconnection unit. And
The center communication device is
After receiving the disconnection notification from the detour base communication device, transmitting a disconnection instruction to the detour destination base communication device and disconnecting the session with the detour destination base communication device, the detour destination A bandwidth reduction session establishment unit that transmits a session establishment request to a base communication device of the base station and a bandwidth that is narrower than the disconnected session, and establishes a session of the bandwidth to be used that is transmitted with the bypass base communication device And further comprising
The center data communication control unit transmits and receives data between the terminal connected to the detour destination base communication device and the service providing device through the session established by the bandwidth reduction session establishing unit.
The traffic detour system according to any one of claims 1 to 5, characterized in that: The detour base communication device is:
A disconnect request unit for transmitting a disconnect request to the center communication device and disconnecting the session with the center communication device;
The center communication device is
A detour destination disconnection instruction unit that receives the disconnection request from the detour destination base communication device, disconnects the session with the detour destination base communication device, and transmits a connection disconnection request to the detour source base communication device; ,
A reconnection establishment unit that transmits a session establishment request to the detour base communication device and establishes a session with the detour source base communication device;
The center data communication control unit transmits and receives data between the terminal connected to the bypass base communication device and the service providing device through the session established by the reconnection establishment unit,
The detour base communication device is:
A detour destination cutting unit that receives the connection disconnection request from the center communication device and disconnects the session with the detour destination base communication device;
The session communication request is transmitted from the center communication device, and a reconnection unit for establishing a session with the center communication device is provided.
The detour source data communication control unit transmits and receives data between the terminal connected to the detour source base communication device and the service providing device using the session established by the reconnection unit,
The traffic detour system according to any one of claims 1 to 5, characterized in that: A traffic detour method used in a traffic detour system in which a center communication device to which a service providing device is connected and a plurality of base communication devices to which terminals are connected is connected via a network,
In the base communication device of the detour source,
A connection requesting process in which a connection requesting unit transmits a connection request to the center communication device;
In the center communication device,
When the connection instruction unit receives the connection request from the bypass base communication device and the number of connections in the session has reached the upper limit, the bypass destination selected from the base communication devices that have already established a session A connection instruction process for returning the communication address of the base communication device;
In the base communication device of the detour source,
Connection in which the connection request unit transmits a session establishment request to the detour destination base communication device specified by the communication address received from the center communication device, and establishes a session with the detour destination base communication device Request process,
In the detour base communication device,
A detour session establishment unit receives a session establishment request from the detour source base communication device, and establishes a detour session establishment process for establishing a session with the detour source base communication device;
In the center communication device,
A band increase session establishing unit transmits a disconnection instruction to the detour destination base communication device to disconnect a session with the detour destination base device;
In the detour base communication device,
A center instruction disconnection unit that receives the disconnection instruction from the center communication device and disconnects the session established with the center communication device;
In the center communication device,
The bandwidth-increasing session establishment unit transmits a session establishment request to the detour base communication device and a use band wider than the disconnected session, and the use band transmitted to the detour base communication device The bandwidth increase session establishment process to establish the session of
In the detour base communication device,
A bandwidth increase reconnection unit receives the session establishment request and the used band from the center communication device, and establishes a session of the used bandwidth received with the center communication device;
In the detour base communication device,
A bypass source data communication control unit transmits and receives data between the terminal connected to the base communication device of the bypass source and the service providing device using the session established in the connection request process. Data communication control process;
In the detour base communication device,
A detour destination data communication control unit transmits and receives data between the terminal connected to the detour destination base communication device and the service providing device using the session established in the bandwidth increase reconnection process. In addition, the data between the terminal connected to the detour-source base communication device and the service providing device, the session established in the detour session establishment process and the bandwidth increased reconnection process established Detour-destination data communication control process relaying using session,
In the center communication device,
A center data communication control unit includes data between the terminal connected to the detour base communication device and the service providing device, and the terminal connected to the detour base communication device and the service provision A center data communication control process for transmitting and receiving data to and from a device through the session established in the bandwidth increase session establishment process;
A traffic detouring method.

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