KR0175466B1 - Public Telecommunication Network Subscriber Registration Device and Call Processing Method in Asynchronous Transfer Mode Switching System - Google Patents

Abstract

The present invention relates to a public telecommunication network subscriber matching device and a call processing method in an asynchronous delivery mode switching system. The present invention provides a sub-highway interface with a time switch unit (10) in the PSTN subscriber matching device (3). A cell assembly / decomposition unit 14 providing a cell assembly / decomposition function of the cell, a user cell from the cell assembly / decomposition unit 14, and an inter-processor message cell from an unexplained interlocking control unit 16 and multiplexed. The ATM switch interface unit 15 transmits the data to the ATM switch interface and demultiplexes the cells received from the ATM switch interface, and decomposes and transmits the cells to the cell assembly / disassembly unit 14 or the interlocking controller 16. It is responsible for the communication function with the PSTN control unit 12 in the PSTN subscriber matching device 3 through a bus interface, and the cell assembly and disassembly unit 14 and the ATM switch through the VME bus. It controls the interface unit 15, and is responsible for the communication function with the PSTN control unit 12 in the PSTN subscriber matching device (3) and the cell assembly and disassembly unit 14 and the ATM switch interface unit 15 via the VME bus And an interworking controller 16 for providing a message matching function between the PSTN control unit 12 in the PSTN subscriber matching device 3 and the ATM control unit 6 in the ATM subscriber matching device 1, and the ATM. And a clock generator 17 for generating the PSTN system clock required for PSTN matching to the ATM system clock from the subscriber matching device 1 and supplying the PSTN system clock to the time switch unit 10.

Description

Public Telecommunication Network Subscriber Registration Device and Call Processing Method in Asynchronous Transfer Mode Switching System

1 is a block diagram of an ATM switching system to which the present invention is applied.

2 is a diagram illustrating a subhighway channel configuration of the PSTN subscriber registration device of FIG.

3 is a cell structure diagram of a switch interface of an ATM switching system.

4 is a functional block diagram of an ATM interworking unit of the PSTN subscriber registration device according to the present invention.

5 is a flowchart illustrating a call processing method through a PSTN subscriber registration device according to the present invention.

* Explanation of symbols for main parts of the drawings

14 cell assembly / disassembly section 15 ATM switch interbase section

16: interlock controller 17: clock generator

The present invention relates to a public telecommunication network subscriber matching device and a call processing method in an asynchronous delivery mode switching system.

The existing Public Switched Telephone Network (PSTN), which was based on voice service, integrates non-voice services such as data transmission as well as voice due to the rapid development of telecommunication technology and various service requests from users. It has developed into an Integrated Services Digital Network (ISDN), and commercial services of such narrowband ISDN (N-ISDN) are currently in progress. However, N-ISDN is limited to the narrowband communication service of 64Kbps or less for the conventional voice and data. Therefore, N-ISDN is a high speed required for various fields, especially video and moving picture data transmission, which are developed according to the recent development of computer, semiconductor and optical communication. It is inadequate to provide data transfer services for mobile phones and also lacks the adaptability and flexibility to meet the needs of various new types of services in the future, including multimedia.

However, Broadband-ISDN (ATM) using Asynchronous Transfer Mode (ATM) aims to accommodate all services that can exist in future networks, such as N-ISDN such as telephony, data terminals, facsimile and teletex. In addition to service coverage, it also provides broadband services such as video telephony and conferencing, high-speed data transmission, CATV and HDTV distribution. Therefore, B-ISDN can be regarded as a communication network that has been expanded to provide various broadband services based on the existing N-ISDN. In the process of integrating and developing existing public telecommunication networks into B-ISDN, it is necessary to interoperate between the existing network and the newly constructed network due to economical efficiency and efficiency.

In accordance with the present invention, the present invention provides a matching device for accommodating existing PSTN subscribers in an ATM switching system, which is a network node of B-ISDN, by utilizing the subscriber matching device of the existing PSTN exchanger to maximize the system development order and stability. Interworking part is formed between PSTN matching part and ATM switch, which enables interworking between PSTN-ATM by performing format conversion of user data and exchange of inter processor communication messages. The purpose of the present invention is to provide a subscriber station and a call processing method for public telecommunication networks in an asynchronous delivery mode switching system.

In order to achieve the above object, the present invention provides an asynchronous transfer mode (ATM) subscriber matching device, an ATM switch device, and a PSTN subscriber registration including a PSTN subscriber means, a time switch, a signal and service means, a PSTN control means, and an ATM interlocking means. An ATM switching system comprising a device, the ATM interworking means comprising: cell assembling / disassembling means for providing a subhighway interface with the time switch and providing a cell assembling / disassembly function of ATM adaptive layer type 1; Receive user cells from the disassembly means via the assembled FIFO, and receive and multiplex the inter-processor message cells from the non-described interworking control means via the IPC transmit FIFO, and vice versa, received from the local switch in the ATM subscriber matching device. ATM switch interface means for demultiplexing and disassembling and transmitting to the cell assembly / disassembly means or interlock control means; Interworking control that performs communication function with the PSTN control unit through a common bus, controls the cell assembly disassembly means and the ATM switch interface means through the VME bus, and provides a message matching function between the PSTN control unit and the ATM subscriber matching device. Way; And a clock generation means for generating a PSTN system clock required for PSTN matching from the ATM subscriber matching device to the ATM system clock and supplying the PSTN system clock to the time switch. do.

In addition, in a call processing method applied to a public telecommunication network subscriber matching device in an asynchronous delivery mode switching system, a subscriber hookoff occurs in a disconnected state, and the PSTN subscriber matching device detects this and transmits a dial tone to the subscriber and digits. A second step of receiving information, transmitting the received digit information to the ATM control means, translating the called number to perform a call processing procedure, and completing a call connection processing procedure and then notifying; By adding sub-highway information (time slot number) of the time switch to which the subscriber is connected, requesting the cell assembly / disassembly start of user data by sending it to the interlocking control means, and updating the control memory based on the received information. A third step of causing / disassembly to be initiated for the connection and bringing the connection to the established state; A fourth step of notifying the ATM control means of a release when the subscriber hooks on in the connection establishment state, performing a disconnection procedure, and then transmitting a response message; And, the PSTN control means requires the cell assembly / disassembly stop for the connection to the ATM interlocking means, and the interlocking control means for which the cell assembly / disassembly stop is requested updates the control memory of the cell assembly / disassembly means to update the cell for the connection. Provided is a call processing method of a public telecommunications network subscriber matching device in an asynchronous delivery mode switching system comprising a fifth step of assembling / disassembling to be disconnected.

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

1 is a block diagram of an ATM switching system to which the present invention is applied, and the entire system includes an ATM subscriber matching device 1, an ATM switch device 2, and a PSTN subscriber matching device 3.

First, the ATM subscriber matching device 1 is composed of an ATM subscriber interface unit 4, an ATM local switch 5, and an ATM control unit 6 in charge of ATM call processing function and operation maintenance in the matching device.

The ATM switch device 2 is composed of an ATM switch 7 for providing a cell exchange function between subscriber matching devices and a system control unit 8 for operating and maintaining the entire system.

The PSTN subscriber matching device 3 includes a PSTN subscriber unit 9 providing a PSTN line connection function, a time switch unit 10 providing a time slot exchange function, supplying call signals to a subscriber line, conference calls, and recording guidance service functions. And a PSTN control unit 12, which controls the overall control of the PSTN subscriber matching device, and the format conversion between the time slot data and the ATM cell, and between the PSTN control unit 12 and the ATM control unit 6. It consists of an ATM interworking unit 13 for performing the inter-processor message format conversion function.

The ATM interworking unit 13 is connected to an ATM local switch 5 in an ATM subscriber matching device and an IMI (Inter Module Interface) which is a standard interface between modules of an ATM switching system.

Looking at the matching process of the user data on the basis of the above system configuration diagram as follows.

The PSTN subscriber information (voice, data) is a subhighway, which is a channelized interface coded by PCM (Pulse Code Modulation) at the PSTN subscriber unit 9, where the subhighway is a 2.048Mbps serial input / output consisting of 32 64Kbps channels. The bit stream) to the time switch unit 10.

2 is a channel configuration diagram on the subhighway of FIG.

The subscriber information exchanged with the time slot (channel) through the time switch is loaded on the output subhighway, and the ATM link unit collects the time slot data input one octet per channel every 125us, and forms an ATM cell for each channel and transmits it to the ATM switch. .

3 is a structural diagram of a cell transmitted to an ATM switch.

As shown in the figure, a routing tag in a cell structure is used for self-routing of a cell in an ATM switch, an ATM cell header provides information for connection identification (VPI / VCI), and the definition of terminology used in the figure is As follows.

C denotes cell loss priority, GFC denotes general flow control, PT denotes payload type, HEC denotes header error control, VPI denotes virtual connection identifier, and VCI denotes virtual channel identifier.

4 is a functional block diagram of an ATM interworking unit according to the present invention, wherein the ATM interlocking unit is a cell assembly / disassembly unit 14, an ATM switch interface unit 15, an interlocking control unit 16 and a clock generating unit 17, and an assembling FIFO. It consists of a decomposition FIFO, an IPC receive FIFO and an IPC send FIFO.

First, the clock generator 17 receives an ATM system clock of 46.94943 MHz from the ATM subscriber matching device 1, supplies 23.4747 MHz divided by 2 to the ATM switch interface unit 15, and requests for PSTN matching. 16.38 MHz and 8 KHz PSTN system clock 22 are generated and supplied to the time switch unit 10.

The cell assembly / decomposition unit 14 receives a 2.048 Mbps bit clock and an 8 KHz frame synchronization signal through a sub highway interface with the time switch unit 10, and transmits channel data through the 2.048 Mbps serial transmission / reception signal 10. Send and receive with

The cell assembly disassembly unit 14 extracts the channel timing of 0-31 according to the bit clock and the frame synchronization clock supplied by the time switch unit 10 and uses the connection timing. Channel data received from the sub-highway is collected in octet units through serial / parallel conversion, assembled into cells of the ATM adaptation layer type 1, and then stored in the assembled FIFO. The cell stored in the assembled FIFO is read by the ATM switch interface unit 15 as a switch link clock of 24.4747 MHz, which is an IMI 18 transmission clock, and transmitted to the IMI 18. The read / write clocks of the assembled FIFOs do not need to be synchronized with each other, and the write clocks are themselves generated by the cell assembly resolver 14 using a 2.048 MHz bit timing and a 20 MHz local clock oscillator. In the reverse direction, the ATM switch interface unit 15 receives the user cell from the IMI and stores it in the decomposition FIFO as a switch link clock of 2334747 MHz, and the cell assembly decomposition unit 14 stores the cell in the decomposition FIFO using a read clock generated by itself. The assembly disassembly unit 14 reads a cell stored in the decomposition FIFO in octet units using a self-generated read clock and transmits data in parallel / serial conversion to a subhighway through a channel corresponding to a corresponding virtual connection (VPI / VCI).

The ATM switch interface unit 15 receives the user cell from the cell assembly disassembly unit 14 through the assembling FIFO, and receives an interprocessor message (IPC) cell from the interlocking controller 16 through the IPC transmission FIFO. The received user cell and the IPC cell are multiplexed and then transmitted to the IMI 18, which is an ATM switch interface. In the reverse direction, the ATM switch interface unit 15 checks the routing tag field (FIG. 3) of the cell header received from the IMI 18 to determine whether the received cell is a user cell or an IPC cell from the ATM control unit 6. In the case of a user cell, the IPC cell is stored in the decomposition FIFO, and the IPC cell is stored in the IPC reception FIFO 40.

The interlocking control unit 16 is responsible for the communication function with the PSTN control unit 12 via the common bus 20 interface. The common bus 20 interface is a serial bus using a high level data link control (HDLC) protocol.

The interlocking control unit 16 receives an interprocessor message (eg, number information) transmitted from the PSTN control unit 12 to the ATM control unit 6 through the common bus and checks the message type to receive the received message. In the case of control information (e.g., channel and VPI / VCI connection establishment / disconnection, etc.), the control information is transmitted to the cell assembly disassembly unit 14 via the VME bus 19, and the ATM control unit 6 If transmission is necessary, it is assembled to the IPC cell of AAL5 and stored in the IPC transmission FIFO via the bus (19). On the contrary, the IPC cell generated from the ATM control unit 6 is stored in the IPC receiving FIFO via the ATM switch interface, and the interlocking control unit 16 reads the IPC cell stored in the IPC receiving FIFO via the VMR bus 19 into a message. After the transmission to the PSTN controller 12 through the common bus according to the HDLC protocol.

5 is a flowchart illustrating a call processing method through a PSTN matching device according to the present invention, and illustrates a control procedure between component blocks when a subscriber establishes and releases a connection.

When the subscriber hookoff occurs in the disconnected state (23), the PSTN subscriber unit 9 of FIG. 1 detects this and notifies the PSTN control unit 12, and the PSTN control unit 10 switches the time switch unit 10 and the signal service unit 11. Control to transmit the dial tone to the subscriber and receive the digit information (24). The PSTN control unit 12 collects the received digit information and transmits the received digit information to the ATM control unit 6 through the ATM interlocking unit 13 (25). In this case, the flow of message processing in the ATM interlocking unit will be described. As shown in FIG. 4, the interlocking control unit 16 receives the message through the common bus 20 and assembles the message in a cell form. Passed to the interface unit to send a message to the ATM switch link. The ATM controller 6 translates the received called number and performs a call processing procedure (26). After completing the call connection processing procedure, the ATM controller 6 notifies the PSTN controller 12 of the result (27). Even at this time, the message to the PSTN control unit 12 passes through the ATM interlocking unit 13, which is an intermediate passage. In the ATM interlocking unit, the ATM switch interface unit 15 receives a cell-type message from the switch link and interlocks it. And transfer the message to the PSTN controller 12 in accordance with the communication protocol on the common bus. The contents of the call processing result message notified by the ATM control unit 6 to the PSTN control unit 12 include a routing tag for self-routing of user data in the system, and a VPI / VCI which is a connection identifier for outgoing and incoming calls. The contents of the call processing result message notified to the PSTN control unit 12 include a routing tag for self-routing of user data in the system, and a VPI / VCI which is a connection identifier for outgoing and incoming calls. In addition to this information, the PSTN control unit 12 adds the subhighway information (time slot number) of the time position to which the subscriber is connected and sends it to the interlocking control unit to request cell assembly / disassembly start for the user data (28). The ATM interworking unit updates the control memory of the cell assembly / disassembly unit 14 based on the received information (29) so that cell assembly / disassembly is initiated for the connection (30). The cell assembly / decomposition unit 14 receives the time slot data on the subhighway of the established connection in octets every 125 us, assembles it into the user cell structure of FIG. 3, and transmits the data to the ATM switch interface unit 15. On the contrary, the cell received from the ATM switch interface unit 15 is disassembly by connection (by VPI / VCI) in the cell assembly / decomposition unit and loaded into a time slot corresponding to the connection to the time switch unit 10. do. When the subscriber hooks on in the connection establishment state (31), the PSTN control unit 12 notifies the ATM control unit 6 of the release (32), and the ATM control unit performs a connection disconnection procedure. After that (33) and sends a response message to the PSTN control unit (34). The PSTN control unit requests a cell assembly / disassembly stop to the ATM interworking unit for the connection (35), and the request message includes a subhighway channel number and a connection identifier (VPI / VCI) corresponding to the released connection. The interlocking control unit 16 in the ATM interlocking unit, which has been requested to stop the cell assembly / disassembly, updates the control memory of the cell assembly / disassembling unit 14 (36) to stop the cell assembly / disassembly for the corresponding connection (37). .

The PSTN subscriber matching device of the present invention as described above uses a subscriber matching device of an existing PSTN switch in a configuration manner and configures a new ATM interlocking unit 13 between the ATM switch and the PSTN matching unit to provide a matching function in the PSTN. It is possible to utilize the secured technology, thereby increasing the stability of the system.

The present description described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, the present invention has an advantage of minimizing a system structure change required to add an interworking function in terms of an ATM switching system.

In addition, since most of the subscriber / network matching device of the existing PSTN and N-ISDN switching system includes a time switch, the subscriber / network matching of the existing PSTN and N-ISDN switching system is possible by using an ATM interworking unit having a time switch interface. Since the connection with the device can be facilitated, the PSTN network and the N-ISDN subscriber / network matching device can be configured in the ATM switching system without further development.

Claims (2)

An ATM switching system comprising an asynchronous transfer mode (ATM) subscriber matching device, an ATM switch device, a PSTN subscriber means, a time switch, a signal and service means, a PSTN control means, and a PSTN subscriber matching device having an ATM interworking means. The ATM interworking means includes a cell assembly / decomposition means for providing a subhighway interface with the time switch and providing a cell assembly / decomposition function of an ATM adaptation layer type 1, and an FIFO assembling user cell from the cell assembly / decomposition means. Through the IPC transmission FIFO, and multiplexing by receiving the inter-processor message cells from the interworking control means, which are not explained, and demultiplexing the cells received from the local switch in the ATM subscriber matching device. Or ATM switch interface means for disassembling and transmitting to the interlocking control means and the PSTN control unit via a common bus. Interworking control means for carrying out a communication function and controlling the cell assembly disassembly means and the ATM switch interface means through a VME bus, and providing a message matching function between the PSTN controller and the ATM subscriber matching device, and from the ATM subscriber matching device. And a clock generation means for generating a PSTN system clock required for PSTN matching with an ATM system clock and supplying the time switch to the time switch. A call processing method applied to a public telecommunication network subscriber matching device in an asynchronous transfer mode switching system, wherein a subscriber hookoff occurs in a disconnected state, and the PSTN subscriber matching device detects this to transmit a dial tone to the subscriber and transmit digit information. In the first step of receiving, the received digit information is sent to the ATM control means, the called number is translated, the call processing procedure is performed, and after the call connection processing procedure is completed, the second step of notification, the times of subscriber access By adding the subhighway information (time slot number) of the location to the interlocking control means, the cell assembly / disassembly is initiated for the user data and the control memory is updated based on the received information so that the cell assembly / disassembly is connected. In step 3, a subscriber establishes a hook-on state in the connection establishment state. The fourth step of notifying the ATM release means of release of the connection, transmitting the response message after performing the disconnection procedure, and the PSTN control means requesting the cell interlocking / disassembly to the ATM interworking means for the connection. And the interlocking control means that is requested to stop the cell assembly / disassembly includes a fifth step of updating the control memory of the cell assembly / disassembly means to stop the cell assembly / disassembly for the corresponding connection and bring it to a disconnected state. Call processing method of subscriber matching device in public telecommunication network in switching system.