KR100198095B1 - Virtual channel connection - Google Patents

Abstract

1. Technical field to which the invention described in the claims belongs

A method for providing a user - to - user switched virtual path connection at the calling user - network interface.

2. Technical Challenges to be Solved by the Invention

Before the subscriber of the broadband integrated communication network requests the setting of the virtual channel connection, the subscriber signaling protocol DSS2 is used to set up the exchange virtual path connection for the subscriber of the broadband integrated communication network in advance so as to establish a connection between the calling subscriber of the home station and the called subscriber I want to easily set up virtual channels.

3. The point of the solution of the invention

In an asynchronous transfer mode (ATM) switching system, when a request for the setting of a user-user exchange virtual path connection to be received to a local station or a subscriber of the other station is requested for a setup request of an exchange virtual path connection of the self- In order to establish a virtual channel connection, a connection path between an originating user and a called user is established using a preset virtual path connection, thereby eliminating the need for a signal procedure for setting up a virtual channel in the network.

4. Important Uses of the Invention

It is used to exchange virtual path between users in broadband integrated information network.

Description

User-to-user exchange on the originating user-to-network connection

In a broadband integrated services digital network (B-ISDN) of an asynchronous transfer mode (ATM), a calling subscriber of a local exchange system exchanges user-user information between an originating subscriber of his / her own station and a called subscriber of his / In the case of requesting the setting of the virtual path connection (User-User Switched Virtual Path Connection, UU-SVPC), the originating user and the network interface use DSS2 (Digital Service Signaling system number 2) To a method for establishing a user-to-user switched virtual path connection (UU-SVPC) between subscribers.

First, with reference to FIG. 1 and FIG. 2, it is intended to help understand the terms used in the present invention and the present invention. The definition of virtual path and virtual channel is as follows.

The transparency connection provided by the ATM layer to the upper layer is called an ATM connection, which is connected to the endpoint by a chain connection of connection elements. There are two types of ATM connections: a virtual channel (VC) and a virtual path (VP).

A virtual channel means a logical unidirectional coupling between link terminals carrying ATM cells, and a virtual path means a logical combination of virtual channels. One virtual channel identifier (VCI) is assigned to each virtual channel, and one virtual path identifier (VPI) is assigned to each virtual path. Within the Virtual Path Connection (VPC), there may be different virtual channel links, which are distinguished by their assigned VCIs. On the other hand, some virtual channels belonging to different virtual paths may have the same VCI. Therefore, one virtual channel is completely identifiable only by the combination of the corresponding VPI and VCI.

The following describes the definition of virtual channel connection and virtual path connection and the possible setting method.

Virtual Channel Connection (VCC) refers to concatenation of virtual channel links to connect between ATM Adaptation Layer (AAL) and connected points. At this time, the virtual channel link means a unidirectional virtual connection path that allows the ATM cells to be transported between the point where the VCI is allocated and the point where the VCI is translated or released. The VCC may be provided via a switching device, or may be provided as a permanent or semi-permanent connection.

The following four methods are available to enable or disable VCC at the user-network interface (UNI).

First, by setting or releasing by reservation without going through a signaling procedure, this applies to permanent or semi-permanent connections.

Second, it uses meta signaling. That is, the meta signal VC is used to set or release the signal VC.

Third, using the user-network signaling procedure, this is a method of using the signal VCC to set or release VCC for end-to-end communication.

Fourth, using the user-user signaling procedure, this is the method of using the signal VCC to set or release the VCC inside the VPC preset between the two user-network interfaces.

A virtual path connection (VPC) refers to the concatenation of virtual path links to connect the point at which the VPI is allocated and the point at which the VPI is translated or released. In this case, the virtual path link means a virtual channel link group that connects between points where VPI is assigned and points where VPI is translated or released. The VPC may be provided through a switching device, or may be provided permanently or semi-permanently.

There are two ways to set or clear VPC between VPC endpoints:

First, as a method of connecting or disconnecting without a signaling procedure, in this case the VPC is set or released by reservation.

Secondly, it is possible to connect or disconnect as needed, by means of VPC connection or release by user control and network control.

The following describes the application of the virtual path.

A virtual path (VP) is a general term referring to a bundle of VC links, where all VC links in the bundle have the same endpoint. A virtual path identifier (VPI) for a virtual path is explicitly assigned to an ATM cell, and a VPI identifies a VC link group sharing the same VPC. Whenever a VP is exchanged in the ATM network, a specific VPI is assigned. A VP link is a unidirectional capability for transporting ATM cells between two ATM entities whose VPI values are translated. VP links are generated by assigning VPI values, and are terminated when VPI is removed.

At the virtual path level, a VPC is provided for user - user, user - network and network - to - network communication. When the VC is exchanged, the VPC supporting the input VC link is terminated first, and the VPC supporting the output VC link is newly created. The application of the virtual path is as follows.

First, a user-to-user VPC is established between TB or SB reference points and provides a virtual path connection to users. ATM network elements transport all the cells associated with this VPC through the same route. The corresponding VPI values are translated in the ATM network element providing the cross connect or exchange function.

Second, the user-to-network VPC is established between the TB or SB reference point and the network node, and is used to connect user devices collectively to the network element.

Third, network-to-network VPCs are established between two network nodes, which are applied to network traffic management and routing. In the network node where the VPC terminates, the VCs in the VP are exchanged or cross-connected with the VCs in the other VPs.

The subscriber signaling protocol DSS2 is essentially a signaling protocol that defines signaling procedures for establishing switched virtual channel connections at the originating and destination UNIs. The exchange virtual channel connection must establish a connection every time the calling user requests it, so that it is necessary to repeatedly perform connection control such as network resource allocation, internal switch path, and the like. Therefore, there is an overhead to repeat the same operation when a virtual channel connection is established for the same calling and called users. In addition, since the quality of service of the requested virtual channel connection is different from the quality of service of the virtual channel connection already set in the transmission link, in order to satisfy the new virtual channel connection while maintaining the service quality of the existing virtual channel connection, Since it is necessary to calculate the necessary network resources considering all the virtual channels, much time and effort are required for network resource allocation

The above problem can be solved by establishing a virtual path connection. The virtual path connection does not require connection control for the virtual channel requiring additional connection since it can switch the ATM cell only to the VPI by bundling the virtual channels of the same route into a bundle. In addition, reserving the pre-network resources necessary for the virtual path connection, when the virtual channel connection is established through the virtual path connection, it is possible to efficiently calculate the required network resource, thereby improving the efficiency of network resource management

In the past, since the virtual path can be set only in the shape of a semi-permanent or permanent virtual path connection by the network manager without a signaling procedure, a lot of information, time and effort are required for the virtual path establishment. Therefore, there is a problem that a network administrator or a user can not immediately create a new route when needed.

To solve this problem, we added a signaling capability to establish a virtual path connection to the DSS2. This is accomplished by setting the bearer class field of the information element BBC (Broadband Bearer Capability) of the SETUP message requesting the virtual connection Transparent VP service is added, and the connection identifier (CID) information element is ignored in the VCI and connection control is performed on the VPCI value.

DSS2 performs the exchange virtual path connection establishment procedure only when the bearer class is a transparent VP service. If the bearer class is not a transparent VP service, the BCOB-A, BCOB-C, and BCOB- X, the existing virtual channel connection establishment procedure is performed.

The virtual path connection established by the signaling procedure is defined as an exchange virtual path connection to distinguish it from the virtual path connection established by the network management control or network manager.

The exchange virtual path connection is established by setting the exchange virtual path connection for the subscriber of the broadband integrated communication network using the subscriber signaling protocol DSS2 before the subscriber of the broadband integrated communication network requests the setting of the virtual channel connection, And to set up a virtual channel easily between the called subscriber and the called subscriber. The exchange virtual route connection can be established between a user and a user, a user and a network, and between a network and a network. In particular, the present invention relates to a method for establishing a connection between a calling subscriber and a called subscriber, The purpose is to provide.

This does not require a signaling procedure for virtual channel establishment in the network by using pre-established virtual path connections between originating and terminating users to establish a virtual channel connection using user-user signaling procedures.

1 shows a relationship between an asynchronous transfer mode (ATM) layer and a physical layer,

2 is a diagram showing a relationship between a virtual path and a virtual channel,

FIG. 3 is an overall structure diagram of an ATM switching system to which the present invention is applied.

4 is a main block diagram for performing the setting of the switched virtual path connection of the ATM switching system,

Figures 5A through 5G are flow diagrams of a procedure for providing a user-user switched virtual path connection in a source user-network connection according to the present invention.

In order to achieve the above object, in an asynchronous transfer mode (ATM) switching system, when setting of a user-user exchange virtual path connection to be received to a local station or a subscriber of another station is requested for a setup request of an exchange virtual path connection, Thereby providing a user-user switched virtual path connection between the calling subscriber and the switching system at the calling user-network interface.

Therefore, when SETUP_ind message is received from the originating subscriber of the local station, the exchange system analyzes the message and requests the establishment of the user-user exchange virtual path connection. Then, the exchange system transmits the virtual path connection And allocates the necessary bandwidth and VPCI so that it can be set. After successfully allocating the band and the VPCI, a Call Proceeding message is transmitted to the calling subscriber and the SETUP_int message is transmitted to the called subscriber connection control block or the outgoing trunk line connection control block.

Upon receiving the SwLinkInfoRP message as a response to the SETUP_int message, the routing tag information of the cell header is transmitted to the related block using the internal switch link path information included in the message, To establish a user-to-user switched virtual path connection for transmission of user data cells.

When receiving the CONNECT_int message from the called subscriber connection control block or the outgoing trunk line connection control block according to the above, a CONNECT_req message is transmitted to the originating subscriber of the local station. At this time, a user-user switched virtual path connection is established between the originating subscriber and the called subscriber And the status of the virtual path connection transits to busy.

Also, the subscriber connection control block, which is in a busy state, requests a releasing procedure of the virtual path connection according to a call release request of the calling subscriber or the called subscriber, and returns the used band, VPCI, and the internal switch link path, And deletes the information.

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

3 is an overall schematic diagram of an asynchronous transmission mode switching system applied to the present invention

In the above structure, an asynchronous transfer mode (ATM) switching system is basically composed of an asynchronous transfer mode ALS, an ATM Central Switching Subsystem (ACS) Of the subsystems.

The Asynchronous Transfer Mode Local Switching System (ALS) is operable as an aggregation device with a constant power ratio together with the Asynchronous Transfer Mode Central Switching System (ACS).

Thus, the asynchronous transfer mode central exchange system (ACS) operates as a distribution device performing the interconnection function between the asynchronous transfer mode local exchange systems (ALS).

In addition, the asynchronous transfer mode local exchange subsystem (ALS) includes an asynchronous transfer mode local exchange subsystem / ALS / BSSDN subscriber (ALS / S) for network broadband integrated information network (BISDN) (ALS / BISDN Trunk, ALS / T) and an asynchronous transmission mode local exchange system (ALS / BISDN Subscriber and Trunk, ALS / / ST).

The asynchronous transfer mode local exchange unit system (ALS / S) as the above-described concentrator includes n * m (n is a natural number), where n is the number of links on the user side (based on 155 Mbps) You can have a house cost.

Therefore, the asynchronous transfer mode central exchange system (ACS) performs the call number translation when the call / connection control is performed in the case of the local station and the incoming call / connection, and in the case of the outgoing call / connection, and performs route control.

In addition, the above-mentioned asynchronous transfer mode central exchange system (ACS) has an operation and maintenance processor (OMP) for the operation and maintenance of the entire system to perform system maintenance, test, measurement and statistical functions, Control function.

FIG. 4 is a main block diagram illustrating the configuration of an exchange virtual path connection in an asynchronous transfer mode (ATM) switching system according to the present invention. The entire virtual path connection establishment procedure will be described with reference to FIG.

When a virtual path connection request is generated from the calling subscriber, the asynchronous transfer mode local switching subsystem (ALS) detects this and performs the virtual path connection service, translates the station number under the supervision of the originating asynchronous transfer mode local switching subsystem (ALS) Asynchronous transfer mode Requests a call number translation or an outgoing route specification to the central exchange system (ACS).

The asynchronous transfer mode central exchange system (ACS) receiving the routing request designates an incoming asynchronous transfer mode local exchange part system (ALS). In addition, the designated Incoming Asynchronous Transfer Mode Local Switching System (ALS) selects an optimal internal switch link path and notifies the outgoing asynchronous transfer mode Local Exchanging Subsystem (ALS) Request a virtual path setup with the switching system. An outgoing asynchronous transfer mode local switching subsystem (ALS) that has been informed of the optimal internal switch link path information establishes a virtual path connection within the system. At this time, the originating asynchronous transfer mode local exchange subsystem (ALS) counts user data cells passing through the virtual path in the busy state, and sends the asynchronous transfer mode central exchange system (ACS ), And the foot / incoming asynchronous transfer mode local exchange subsystem (ALS) restores the call / connection data to the dormant state.

FIG. 4 illustrates a main call / connection processing block for performing the virtual path connection control procedure as described above, and each block will be described below.

First, a system library block includes a Switch Link Resource Handling Function (SLRHF), a Number Translation in ALS Function (NTLF), a User Link Resource Handling Function (ULRHF), and Network Link Resource Handling Function (NLRHF).

The switch link resource management block SLRHF is a block for generating internal switch link path setting and route specifying information of an asynchronous transfer mode cell header (ATM cell header), and the station number translation block NTLF (ULRHF) is a block for performing bandwidth allocation and band management of a subscriber link at a user-network interface, and the network link resource management processing block (NLRHF) - Blocks for bandwidth allocation and bandwidth management of trunk link at network interface (NNI).

In addition, the Broadband Signaling Interface Function (BSIF) controls and manages signaling connections for reliable transmission of Broadband Integrated Services Digital Network (B-ISDN) call / connection control messages. The Subscriber Service Specific Coordination Function (SSCF) block provides an adjustment function between the BSIF and the User Connection Interface Function (UCIF) . The User Connection Interface Function (UCIF) performs the connection function of the subscriber signaling message. The subscriber connection control block (UCCF) performs subscriber call / connection control.

The Trunk Service Specific Coordination Function adjusts between the BSIF and the MTP-3 Signaling Message Handling Function (SMHF) to deliver the trunk line signaling message. Function. MTP Signal Message Processing Block (SMHF) Performs MTP-3 function among No.7 signaling methods.

The Trunk Connection Interface Function (TCIF) performs an MTP signaling message transfer function between the MTP signaling message processing block (SMHF) and the network connection control function block.

A Trunk Connection Control Function (TCCF) block performs call / connection control of a B-ISDN User Part (BISUP) user unit.

And number translation in ACS for routing number translation and routing control function (RTCF) block for routing control.

5A-5F are flow diagrams for providing an exchange virtual path connection between a user and a user at the originating user-network interface according to the present invention.

A detailed procedure of providing a user-user exchange virtual path connection will be described with reference to the drawings.

5A shows a procedure for creating a child process for setting up an exchange virtual path connection between a user and a user in a UCCF main process (UCCF main process) of a subscriber connection control block (UCCF).

5B to 5F illustrate a case where the originating VP path subprocess (UCCF_vporg) generated by the main process of the subscriber connection control block (UCCF_main process) provides the exchange virtual path connection between the user and the user FIG.

In the above procedure, the main process (UCCF_main) of the subscriber connection control block (1) receiving the call / connection setup request message from the originating subscriber (2) (BS) of a Broadband Bearer Capability (BBC) information element is a virtual path (VP) and a Connection Identifier (CID) information element is a Virtual Path Connection Identifier VCCI), it is determined that the setting of the user-user exchange virtual path connection is requested, and the originating subscriber virtual path connection unit process (UCCF_vporg) is generated (3).

However, if the call / connection setup request message indicates that the transmission class (BS) of the BBC information element is Broadband Connection Oriented Bearer Service-A (BCOB-A), the broadband connection- (Broadband Connection Oriented Bearer Service-C or BCOB-C) or Broadband Connection Oriented Bearer Service-X (BCOB-X) and the CID information element is a Virtual Path Connection Identifier If the virtual channel identifier (VCI) is included, it is determined that the virtual channel connection is requested and the originating VC virtual channel connection process (UCCF_vcorg) is generated (4).

Upon receipt of the virtual path connection setup (main-child SETUP, SETUP_mc) message from the main process (UCCF_main), the generated secondary process (UCCF_vporg) checks the available network resources (6) If it can accommodate the band and virtual path connection identifier (VPCI), it forwards the CALL PROCEEDING message to the calling subscriber (7). However, if the originating subscriber's request can not be accommodated, the RELEASE COMPLETE message is delivered to the calling subscriber and the sub-process (UCCF_vporg) ends.

After transmitting the call progress message to the calling subscriber, the subprocess (UCCF_vporg) calls the system library of the station number translation block (NTLF) to select the called local switching system (ALS) to translate the called number. (8) If it is determined that the call is a local call, the called number translation block (NTCF) requests the translation of the called number (9). The location information of the called subscriber can be known as a result of the called number translation. If it is determined that the call is relayed by the translation of the station number, the routing control block (RTCF) requests the designation of the outgoing route (10). As a result of the routing request, the information of the outgoing route and the signaling point code (SPC) information of the incoming exchange system can be known.

After performing the above procedure, it invokes the system library of the switch link resource management processing block (SLRHF) to reserve the internal switch link path between the originating local exchange system (ALS) and the destination local exchange system (ALS) 11).

If all the above procedures are successfully performed, the calling part process (UCCF_vporg) transmits an internal call / connection (UCCF_vporg) including the internal switch link information reserved in the main process (UCCF_main) of the called subscriber connection control block, (12) a switch link information response message waiting state (Await_SwLinkInfoRP; 13), and transmits the setup request (Internal SETUP to UCCF, SETUPU_int) message. The destination primary process (UCCF_main) receiving the internal call / connection setup request (SETUPu_int) message generates the destination VPNCF process (Destination VP UCCF child process, UCCF_vpdes) by performing the same procedure as the source primary process .

If the translation result of the station number is a relay call, the calling part process (UCCF_vporg) transmits an internal SETUP to request including the internal switch link information reserved in the main process (TCCF_main) of the destination terminating relay trunk line connection control block TCCF, SETUPt_int) message (14) and transits to the switch link information response message waiting state (Await_SwLinkInfoRP) (13). The destination primary process (TCCF_main) receiving the internal call / connection setup request (SETUPt_int) message performs the same procedure as the source primary process to output the outgoing VPCCF child process (TCCF_vpogt) Generate

When the sender process (UCCF_vporg) receives a switch link information response message (SwLinkInfoRP) including the switch path information selected from the called party process (UCCF_vpdes or TCCF_vpogt) in the switch link information response message waiting state (Await_SwLinkInfoRP) The system library of the link resource management processing block (SLRHF) is called to set the internal switch path of the virtual path connection (16). The calling part process UCCF_vporg transmits a message including the virtual path identifier (VPI) and information for user parameter control (UPC) to the subscriber interface module controller (SIMC) 17, 18) After receiving the response, it transits to the call connection completion wait state (Await_CONNECT) (20).

(UCCF_vpogt) receives an INTERNAL CONNECT (CONNECT_INT) message from the called party process (UCCF_vpdes or TCCF_vpogt) in a call connection completion waiting state (Await_CONNECT) (21) (22) after a call connection completion (CONNECT_req) message informing that the setting of the exchange virtual path connection is completed between the originating and terminating subscriber, and transits to the conversation state (23). From this point on, the user data cell is transferred between the two subscribers via the established virtual path connection.

The procedure for releasing the virtual path connection may be performed at the request of the originating or terminating subscriber. In the case of performing the procedure of releasing the virtual path connection according to the request of the originating subscriber, the originating subscriber starts by transmitting a call / release request (RELEASE_req) message to the originator process (UCCF_vporg). The originator process (UCCF_vporg) receiving the call / release request (RELEASE_ind) message from the originating subscriber checks (24) whether there is a virtual channel connection in the virtual path connection before releasing the virtual path connection (25) If there is a virtual channel connection, the virtual channel connection is released first and then the virtual path connection release procedure is started. (UCCF_vporg) calls the system library of the switch link resource management processing block (SLRHF) to release the internal switch path corresponding to the virtual path connection (26) and deletes the virtual path identifier to the subscriber access module controller (27). (28) forwards a message requesting release of the virtual path connection to the called party process (UCCF_vpdes or TCCF_vpdes) (28) and notifying the calling subscriber that release of the virtual path connection is complete After notifying the RELEASE COMPLETE_req message (29), the user-user switched virtual path connection established at the calling user-network interface is released and the calling process terminates.

In the case of performing the procedure of releasing the virtual path connection according to the request of the called subscriber, the called subscriber starts by transmitting a call / disconnection request (RELEASE_req) message to the called party process (UCCF_vpdes or TCCF_vpogt). Upon receiving the call / connection release request (RELEASE_ind) message from the called subscriber, the called party process (UCCF_vpdes or TCCF_vpogt) releases the virtual path connection and transmits a RELEASE_int message to the calling process (UCCF_vporg) . The calling process (UCCF_vporg) receiving the call / connection release request (RELEASE_int) message checks (30) whether there is a virtual channel connection in the virtual path connection before releasing the virtual path connection (31) The virtual channel connection is released first and the virtual path connection release procedure is started (32). The called party process (UCCF_vpdes or TCCF_vpogt) calls the system library of the switch link resource management processing block (SLRHF) to release the internal switch path corresponding to the virtual path connection (33) and sends the virtual path connection to the subscriber connection module controller Requesting deletion of the identifier (34). (35) a call / release request message (RELEASE_req) requesting release of the virtual path connection to the calling subscriber, and transitions to the call / disconnect complete message waiting state (Await_Release Complete) (36). After receiving the RELEASE COMPLETE_ind message informing that the release of the virtual path connection from the calling subscriber is completed (37), the user-user exchange virtual path connection established at the calling side user-network interface is released, The secondary process ends.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. It is not.

The method of providing a user-to-user exchange virtual path connection in a source-side user-network interface of the present invention as described above is characterized in that a user-user exchange virtual path connection is established between a calling subscriber and an originating exchange system by a subscriber signaling protocol (DSS2) User exchange virtual route connection between the originator and the called subscriber by performing the virtual path setting procedure for the requested local call or relay call, and can provide the user-user switched virtual path connection between the originating subscriber and the originating subscriber, It is possible to provide an ATM service to a called party of the local station or another station in response to a request for a transmission mode (ATM) service.

Claims (8)

In the asynchronous transfer mode (ATM) switched system, a virtual connection is established between the called station and the called subscriber of the called station or the called subscriber of the other station in response to the setting request of the user-user switched virtual path connection required by the calling subscriber of the local station. A method for providing a user-user exchange virtual path connection in a connection plane, When the result of analyzing the call / connection setup request (SETUP_ind) message received from the originating subscriber requests the local call or the relayed call exchange virtual path connection, the calling subscriber virtual path connection control unit process or the outgoing relay line virtual path connection Comprising: a first step of generating a control unit process; When the originating subscriber virtual path connection controller process generated from step 1 receives a call setup request (SETUP_mc) requesting an exchange virtual path connection from the main process of the subscriber connection control block, A second step of allocating a bandwidth and a virtual path connection identifier (VPCI) After the execution of the second step, the call destination station number is translated to determine whether it is a local call or a relay call. After reservation of the internal switch link path, an internal call / connection setup request (SETUP_int or SETUPt_int) message is transmitted to the called subscriber or the outgoing trunk line connection control To a block, A fourth step of setting a path for transmission of the user information cell using the switch link information received from the called subscriber or the outgoing trunk line virtual path connection control unit process after the third step; After receiving a CONNECT_int message from an incoming or outgoing relay subprocess, a call connection completion message (CONNECT_req) is transmitted to the calling subscriber informing that the establishment of the exchange virtual path connection between the caller and the called subscriber is completed, A fifth step of making the state of the path connection as busy, A sixth step of performing a procedure for releasing the virtual path connection in the call in response to a release request of the virtual path of the calling subscriber after the fifth step; And a seventh step of performing a procedure of releasing the virtual route connection in the call in response to a request for releasing the virtual path of the called subscriber after the fifth step. . The method according to claim 1, In the first step, When the main process of the subscriber connection control block which receives the SETUP_ind message from the originating subscriber of the local station requests setting of the exchange virtual path connection as a result of message analysis, the calling subscriber virtual path connection unit process is created A method for providing a user-switched virtual path connection. The method according to claim 1, The second step comprises: (ULRHF) system library for the virtual path connection requested by the originating subscriber virtual path connection control unit process, allocates the requested bandwidth and virtual path connection identifier (VPCI), and then transmits the call progress CALL PROCEEDING_REQ message to the originating subscriber. The method according to claim 1, In the third step, If the translation result of the called station number is a local call, it translates the incoming number, finds the incoming ALS and the subscriber transmission link, reserves the internal switch link path information between the originating and terminating local exchange sub-systems, (SETUPu_int) message requesting the setting to the main process of the called subscriber connection control block, If the translation result of the called station number is a relay call, it requests the designation of the route to be relayed to the external station, finds the incoming local exchange system (ALS) and the outgoing trunk line link, and transmits the internal switch link path And transmitting an internal call / connection setup request (SETUPt_int) message requesting the setting of the virtual path connection to the main process of the outgoing trunk line connection control block. Exchange virtual path connection. The method according to claim 1, In the fourth step, The switch link resource management processing block SLRHF receives the switch link information response message including the internal switch link path information selected by the called subscriber or the outgoing trunk line virtual path connection control subprocess, Path, and the virtual path identifier (VPI) and the information for controlling the user parameters are transmitted to the subscriber access module controller. The method according to claim 1, In the fifth step, After receiving the INCONNECT_IND message from the incoming or outgoing relay subprocess, the call connection completion notification (CONNECT_req) is sent to the calling subscriber to inform the originating subscriber of the establishment of the user-user exchange virtual path connection setup between the calling subscriber and the originating exchange system A method of providing a user-to-user exchange virtual path connection that sends a message to make the status of a virtual path connection in the call. The method according to claim 1, In the sixth step, A procedure of releasing a virtual path connection in a call according to a request of a calling subscriber, the method comprising: receiving a call / connection release request (RELEASE_ind) message from a calling subscriber and deleting a used internal switch link path and a virtual path connection identifier (VPCI) A user-to-user exchange of virtual path connections that delivers an internal call / release request (RELEASE_int) message to the called subscriber or outgoing trunk line connection control process and notifies the originating subscriber of the RELEASE COMPLETE_req message Delivery method. The method according to claim 1, In the seventh step, A method for releasing a virtual path connection in a call according to a request of a called subscriber, the method comprising: receiving an internal call / release request (RELEASE_int) message from a called subscriber or an originating trunk line process; A method of providing a user-to-user exchange virtual path connection that performs deletion of an identifier (VPCI), delivers a call / disconnection request (RELEASE_req) message to the calling subscriber and receives a RELEASE COMPLETE_req message from the calling subscriber .