KR100237403B1 - Apparatus of interfacing ds1e subscriber of atm switching system - Google Patents

Abstract

Among the subscriber matching devices of the ATM switching system, the DS1E subscriber matching device that transmits an ATM cell in a DS1E frame to exchange a cell with a subscriber has a transmission speed of 2 Mbps. However, the switch port of the ATM switcher can basically connect the STM-1 subscriber matching device having a transmission rate of 155Mbps. Thus, the DS1E subscriber matching device can multiplex about 80 subscribers and connect them with one switch port. However, considering the switch port utilization and PBA size, 64 subscribers can be configured and 64 subscriber's physical layer processing units cannot be accommodated in one PBA. The layered PBA can be accommodated. In the ATM layered PBA, the VPI and VCI of the cell received from the switch must be referred to to determine which PBA to which physical layer to transmit the cell to. Therefore, in the present invention, a circuit for managing a connection identifier is configured using VPI / VCI, and the connection identifier of each cell is found using the VPI / VCI of the cell inputted from the switch, and each managed using the connection identifier is used. By using the subscriber connection information, a device for outputting a 16-bit transmission cell bus is configured by adding a destination PBA number to which the cell is directed and a line number of which cell should be output to which subscriber line of the PBA.

Description

ATM Switch DS1E Subscriber Registration Device

The present invention relates to an ATM switch DS1E subscriber matching device.

A switch port of an ATM switcher can basically connect an STM-1 subscriber matching device having a transmission speed of 155Mbps.

Thus, a cell is input at a speed of about 155 Mbps from the switch to the subscriber matching device.

On the other hand, DS1E subscriber matching device is a speed that can accommodate about 80 subscribers, but it can be configured to accommodate 64 subscribers in consideration of switch port utilization and PBA size, and can accommodate all 64 subscriber physical layer processing units in one PBA. If you configure it to accommodate 4 subscribers in one PBA, you can accommodate up to 16 physical layer-processing PBAs. ATM layer-processing PBAs refer to the VPI and VCI of the cell received from the switch and refer to the cell's few physical layers in any PBA. It should be determined whether it should be sent to the processor.

Therefore, in the present invention, a circuit for managing a connection identifier is configured using VPI / VCI, and the connection identifier of each cell is found using the VPI / VCI of the cell inputted from the switch, and each managed using the connection identifier is used. Using the virtual connection information, a device for outputting a 16-bit transmission cell bus is added to an ATM cell by adding a destination PBA number to which a cell is directed and a line number of which cell should be output to which subscriber line of the PBA.

Conventionally, in order to transmit a cell to a physical layer processing unit in several PBAs, it is necessary to provide a separate signal line with a PBA selection signal informing each physical layer PBA that an ATM cell should be output to the corresponding PBA for each PBA.

However, in the present invention, the PBA map indicating the output PBA and the line number indicating the cell to which the subscriber should be outputted are added to the cell service for diagnosis of the cell destined for the physical layer PBA.

Then, when each physical layer PBA checks the first word of each cell and receives a cell having the corresponding physical layer PBA bit set, the cell is transmitted to the subscriber by referring to the line number and outputted to the subscriber.

When the cell is transferred from the ATM layer processor to the physical layer processor, if a PBA selection signal is provided separately from the cell bus, 16 signal lines must be separately implemented in the back plane.

As the number of signals on the backplane increases, crosstalk between the signals can occur and it becomes difficult to design the backplane.

Therefore, as in the present invention, if the PBA bitmap is added to the front of the cell to output the cell on the cell bus and the cell is selected from the physical layer processing PBA and output to the subscriber, the signal line of the backplane can be reduced, which is efficient.

1 is a block diagram of an ATM switch DS1E subscriber matching device.

2 is an ATM layer processing PBA configuration.

3 is a physical layer processing PBA configuration diagram.

4 is a configuration diagram of a transmission cell processing unit.

5 is a configuration diagram of a transmission connection cell management unit.

6 is a configuration diagram of a transmitting cell manager.

7 is a structure of transmission connection management information.

8 is a form of a cell transmitting over an transmit cell bus from an ATM layer processing PBA to a physical layer processing PBA.

* Explanation of symbols for main parts of the drawings

100: transmitting cell processing unit 120: receiving cell processing unit

130: transmission cell processing unit 140: control unit

150: switch link matching unit 200: backplane PBA

300: physical layer processing PBA

Hereinafter, the configuration and operation of the present invention through the accompanying drawings will be described in detail.

1 shows the configuration of a DS1E subscriber matching device of an ATM switch.

The DS1E subscriber matching device is an ATM layer processing PBA 100 that performs ATM layer processing function, switch matching function, and cell multiplexing demultiplexing function, performs line matching of DS1E subscribers, extracts an ATM cell, and then multiplexes and reverses it. It consists of a plurality of physical layer processing PBA (300) for performing multiplexing, the backplane PBA (200) to provide an interconnection between the ATM layer processing PBA (100) and the physical layer PBA (300) and to be mounted in the system.

In the physical layer processing PBA 300, the signal of the subscriber line is interrupted, the maintenance signal included in the DS1E frame is processed, the ATM cell is extracted, the first multiplexing is performed, and then the reception cell bus 2 is used. When the cell is delivered to the ATM layer processing PBA 100 and receives a cell to be transmitted to the subscriber through the transmitting cell bus 3 from the ATM layer processing PBA 100, the PBA bit map added to the front end of the cell is examined. The cell is extracted from the transmitting cell bus 3 and transmits the cell to the subscriber according to the line number.

2 shows the internal structure of the ATM layer processing PBA 100.

When the reception cell processing unit 120 of the ATM layer processing PBA 100 receives a notification that an ATM cell has been received from the reception cell bus 2 in the backplane PBA 200, the reception cell processing unit 120 receives the reception to the corresponding physical layer processing PBA 300. A selection signal is sent through the cell bus 2 to read and multiplex the cell from the physical layer processing PBA 300, converts the header of the receiving cell using the reception connection information, and transmits the header to the switch link matching unit 150. .

The switch link matching unit 150 receives the cell from the reception cell processing unit 120, converts the cell into a form used by the switch link 1, and transmits the cell to the switch link 1.

On the other hand, upon receiving the cell from the switch link 1 performs a function of delivering the cell to the transmitting cell processing unit 130.

When the transmitting cell processor 130 receives the user cell from the switch link matching unit 150, the output cell PBA bitmap and the line number are added to the front end of the cell using the transmission connection information and converted into 16 bits. Pass the cell to

The control unit 140 manages the state of the physical layer processing unit in each physical layer processing PBA 300 through the control bus 4, manages the reception connection information in the receiving cell processing unit 120, and transmits the transmission cell processing unit ( Performs a function of managing transmission connection information of 130).

An example of an internal configuration of the physical layer processing PBA 300 shown in FIG. 3 is illustrated.

The physical layer processing PBA 300 includes a cell multiplexing / demultiplexing unit 310, a predetermined number of transmitting user cell buffers 320, a predetermined number of physical layer processing units 350, a physical layer controlling unit 340, and a control buffer 330. ) And the like.

The cell multiplexer / demultiplexer 310 receives a cell from the transmit cell bus 3, examines the output PBA bitmap, extracts a cell destined for itself, and references the line number to the corresponding transmit user cell buffer 320. After receiving the notification from the physical layer processor 340 that the cell has been received, the cell is read from the physical layer processor 350 to perform the first multiplexing, the cell is stored in the receiving cell buffer, and then the receiving cell bus (2) the ATM layer processing PBA 100 is notified of the cell reception to read the cell from the ATM layer processing PBA.

The physical layer processor 350 checks whether a cell is input to the transmitting user cell buffer 320, reads out a cell to be transmitted, loads the cell in a DS1E frame, and delivers the cell to the subscriber, processes the DS1E frame input from the subscriber, and ATM The cell is extracted and stored in an internal buffer, and the cell multiplexer / demultiplexer 310 reads the cell.

The physical layer controller 340 periodically checks the internal registers of the physical layer processing units 350 to monitor the state of the line and records a failure in the control bus buffer 330 in the ATM layer processing unit PBA 100. It is possible to monitor the state of each physical layer processing unit 350 through the Ferber 330.

The transmitting user cell buffer 320 is required for speed matching since the cell processing speed of the physical layer processor 350 is about 1.9 Mbps and the cell output speed of the cell multiplexer / demultiplexer 310 is about 155 Mbps. The control bus buffer 330 is required for communication between the control unit 140 and the physical layer control unit 340 of the ATM layer processing PBA.

4 shows an internal configuration of the transmission cell processing unit 130 to which the present invention is applied.

The transmit cell processor 130 includes a user cell buffer 131, a management cell buffer 132, a transmit connection identifier manager 133, and a transmit cell manager 134.

The transmission connection identifier management unit 133 checks whether the user cell buffer 131 and the management cell buffer 132 contain a cell to be transmitted to the subscriber, and reads and multiplexes the user cell 6 and the management cell 7. Extracts the connection identifier by extracting the Virtual Path Identifier (VPI) / VCI (Virtual Channel Identifier) and the connection identifier (8) to the transmitting cell manager 134 to determine whether the connection is a virtual path connection. The cell data 10 is transmitted to the transmitting cell manager 134 together with the connection type 9 indicating whether the virtual channel is connected.

The transmitting cell management unit 134 reads the connection management information using the connection identifier 8 received from the transmission connection identifier management unit 133, adds the output PBA bit map and line number to the front of the cell, and converts the transmission cell into 16 bits. (11) is output to the transmission cell bus 3.

5 shows an internal configuration diagram of the transmission connection identifier management unit 133.

The transmission connection identifier management unit 133 includes a transmission connection identifier management circuit 133a composed of a field programmable gate array (FPGA), a virtual path connection identifier table 133b composed of dual port RAM (DPRAM), and a CAM. And a connection identifier table 133c composed of (Content Address Memory).

Inside the transmission linkage identifier management circuit 133a, a cell multiplexer 133a ₁ , a virtual path linkage identifier control unit 133a ₂ , and a linkage identifier table management unit 133a ₃ are configured.

The cell multiplexer 133a ₁ checks whether there are cells to be transmitted to the subscriber in the user cell buffer 131 and the management cell buffer 132, and if there are cells to be transmitted, outputs a read signal to each buffer to read the cells. The user cell 6 and the management cell 7 are multiplexed, and the VPI and VCI are extracted from the header of the cell and transferred to the path connection identifier controller 133a ₂ and the connection identifier table manager 133a ₃ .

When the path connection identifier controller 133a ₂ receives the VPI from the cell multiplexer 133a ₁ , the path connection identifier controller 133a ₂ outputs the VPI to the virtual path identifier table 133b to read the virtual path connection identifier 11 of the corresponding VPI.

The virtual path identifier table 133b configures a DPRAM to simultaneously read and write the transmission connection identifier management circuit 133a and the control unit 140. The virtual path connection identifier 11 indicates that a connection of a cell having a corresponding VPI is performed. It consists of a connection type bit 1 bit indicating whether a virtual path connection or a virtual channel connection, and 7 bits of a virtual path connection identifier. The 8-bit information is stored by the control unit 140, and the transmission connection identifier management circuit 133a does this. The cell is read to find out whether the cell is a cell for virtual path connection or a cell for virtual channel connection.

The virtual path connection identifier controller 133a ₂ transfers the virtual path connection identifier 11 read from the virtual path connection identifier table 133b to the connection identifier table manager 133a ₃ .

The connection identifier table manager 133a ₃ connects from the connection identifier table 133c by using the virtual path connection identifier 11 received from the virtual path connection identifier controller 133a ₂ and the VCI received from the cell multiplexer 133a ₁ . Extract the identifier 12.

The connection identifier table 133c includes a CAM. The CAM checks whether input data matches data stored in the internal memory, and outputs the address of the memory where the matching data is stored. When used as a connection identifier, it is a very useful device as a table for managing connection identifiers.

In the present invention, the CAM is used as the connection identifier management table 133c, and the data registered in the CAM registers 24 bits of data including the virtual connection identifier 8 bits and the VCI 16 bits in the CAM.

When the cells are multiplexed and output, the connection identifier table manager 133a ₃ outputs the virtual path connection identifier and the VCI to the connection identifier table 133c to extract and output the connection identifier 8.

In the case of a virtual path connection, the VCI is set to 0 and only the virtual path connection identifier 11 is output to the connection identifier table 133c so that the connection identifier can be found only by the virtual path connection identifier regardless of the VCI of the multiplexed cell. do.

6 shows a detailed configuration of the transmitting cell manager 134. As shown in FIG.

The transmission cell management unit 134 includes a transmission cell management circuit 134a and a transmission cell management table 134b.

The transmit cell management circuit 134a is composed of a field programmable gate array (FPGA) such that the cell input unit 134a ₁ , the cell output unit 134a ₂ , and the table control unit 134a ₃ are configured. ) Is configured as DPRAM (Dual Port Random Access Memory) to allow simultaneous reading and writing by the transmitting cell manager 134a and the controller 140.

In the cell input unit 134a ₁ of the transmission cell management circuit 134a, a connection identifier 8 is transmitted from the transmission connection identifier management unit 133, a connection type 9 signal indicating whether the connection is a virtual path connection or a virtual channel connection, and a cell. Receiving the data 10 signal and the like, the cell data is transmitted to the cell output unit 134a ₂ , and the remaining signals are transmitted to the table control unit 134a ₃ .

The table controller reads connection information of the connection from the transmission cell management table 134b using the connection identifier 8.

The transmission cell management table 134b has connection information for each connection.

The connection information in the transmission cell management table 134b converts the output PBA bit map 46, the subscriber line number 47, and the header of the output cell to which the cell of the connection should be output, as shown in FIG. H (output cell header conversion request bit) bit 52 indicating whether or not to be connected, C bit 53 indicating the connection type, OAM cell generated when generating the OAM cell to generate a single-to-end OAM cell 0 bit 54 indicating whether to generate segment OAM cells, output VPI 48, output VCI 49, output cell counter 50, A bit 56 indicating whether continuity checking is enabled, Continuity check counter 51 and the like.

In the cell output section, a 56-byte cell is added to the cell data received from the table control section 38 and the cell input section 36 by adding an output PBA bitmap obtained from the connection information and 3 bytes of subscriber line numbers. The transmission cell 11 is outputted to the transmission cell bus after conversion to the cell form.

A method of transmitting a cell to a DS1E subscriber using a device having such a configuration is as follows.

First, when the ATM layer processing PBA 100 receives a cell from the switch link 1, the switch link matching unit 150 stores the cell in the user cell buffer 131 of the transmitting cell processing unit 130.

Then, the transmission connection identifier management unit 133 reads the user cell 6 of the user cell buffer 131, extracts the VPI / VCI from the header of the cell, finds the connection identifier, and identifies the connection identifier 8 and the cell data 10. Is transmitted to the transmitting cell managing unit 134, and the transmitting cell managing unit 134 reads the transmitting connection management information from the transmitting cell management table 134b using the connection identifier, and outputs the PBA bitmap and the output line number 3 to the diagnosis of the cell. A 56-byte cell is created by adding bytes, converted into 16-bit data, and output to the transmit cell bus 3.

The physical layer processing PBA 300 examines the first word of the cell input to the transmitting cell bus 3, extracts only the cell destined for itself, checks the line number, and sends the user to the front end of the corresponding physical layer processing unit 350. The cell buffer 320 stores an 53-byte ATM standard cell from which the output PBA bitmap and line number 3 bytes are removed.

Then, the physical layer processor 350 reads the cell from the transmitting user cell buffer 320 and loads the cell in the DS1E frame to the line subscriber 5.

The present invention receives a cell from a switch link having a cell transmission rate of 155 Mbps, finds a cell's connection identifier using the cell's VPI / VCI, and uses the connection identifier to output an output PBA bitmap in the connection management information, When the output subscriber line number is added to the cell and the cell is output to the cell bus, each physical layer processing PBA extracts only the cell destined for itself and transmits the cell to the subscriber according to the line number, thereby providing multiple physical layer PBAs on one switch link. When connecting and accommodating multiple subscribers in each PBA, an output subscriber can be selected to configure a device capable of transmitting a cell to the subscriber.

Among the subscriber matching devices of the ATM switch, the DS1E subscriber matching device, which transfers an ATM cell to a subscriber by loading an ATM cell in a DS1E frame, has a transmission speed of 2 Mbps.

However, the switch port of the ATM switcher can basically connect the STM-1 subscriber matching device having a transmission rate of 155Mbps.

Thus, the DS1E subscriber matching device can multiplex about 80 subscribers and connect them with one switch port.

An object of the present invention is to provide a configuration and demultiplexing method of an apparatus for demultiplexing a cell received from a switch port from a DS1E subscriber matching device to each subscriber line.

Claims (10)

An ATM layer processing PBA (100) that performs ATM layer functions and performs switch link matching and cell multiplexing and demultiplexing; A physical layer processing PBA (300) comprising a plurality of physical layer processing PBAs 300 which perform line matching of DS1E subscribers and extract ATM cells to perform multiplexing, demultiplexing, and physical layer functions; A backplane consisting of a receiving cell bus (2), a transmitting cell bus (30), and a control bus (4) that provide the interconnection of the ATM layer processing PBA 100 and the physical layer processing PBA 300 and allow them to be mounted in a system. DS1E subscriber matching device of the ATM switch, characterized in that consisting of a PBA (200). 2. The ATM layer processing PBA (100) of claim 1, wherein the ATM layer processing PBA (100) receives a notification that an ATM cell has been received from a reception cell bus (2) in the backplane PBA (200), and sends a notification to the corresponding physical layer processing PBA (300). Sending a selection signal through the receiving cell bus (2) to read and multiplex the cell from the physical layer processing PBA (300), and converts the header of the receiving cell using the reception connection information to transfer to the switch link matching unit 150 A receiving cell processor 120; The cell transmitted from the receiving cell processing unit 120 is converted into a cell used in the switch link to transmit the cell to the switch link 1, and when the cell is received from the switch link 1, the cell is transmitted to the transmitting cell processing unit 130. A switch link matching unit 150 for transmitting; When the user cell is received from the switch link matching unit 150, an output PBA bit map and a line number are added to the front of the cell using the transmission connection information, and the data is converted into 16 bits to transmit the cell to the transmission cell bus 3. A cell processor 130; The control bus 4 manages the state of the physical layer processing unit in each physical layer processing PBA 300, manages the reception connection information in the receiving cell processing unit 120, and controls the transmission cell processing unit 130 of the transmission cell processing unit 130. DS1E subscriber matching device of the ATM switch, characterized in that the control unit for managing the transmission connection information. The PBA according to claim 1, wherein the physical layer processing PBA 300 receives a cell from the transmitting cell bus 3, examines an output PBA bit map, extracts a cell destined for itself, and refers to a corresponding transmitting user cell by referring to a line number. When the cell is delivered to the buffer 320 and the notification is received from the physical layer controller 340, the cell is read from the corresponding physical layer processor 350 to perform primary multiplexing, and then the cell is received in the receiving cell buffer. A cell multiplexing / demultiplexing unit 310 for storing and notifying the cell reception to the ATM layer processing PBA 100 through the receiving cell bus 2 so that the cell is read by the ATM layer processing PBA; It checks whether a cell is input to the transmitting user cell buffer 320 and if there is a cell to be transmitted, reads it and loads the cell in the DS1E frame to the subscriber, processes the DS1E frame input from the subscriber, extracts the ATM cell, and stores the cell in the internal buffer. A physical layer processor 350 which stores and informs the cell multiplexer / demultiplexer 310 to read the cell; The internal registers of each physical layer processor 350 are periodically checked and the state of the line is monitored, and when a failure occurs, the controller registers it in the control bus buffer 330 and the ATM layer processor PBA 100 passes through the buffer 330. A physical layer controller 340 for monitoring a state of each physical layer processor 350; A transmitting user cell buffer 320 necessary for matching the cell processing speed of the physical layer processor 350 with the cell output speed of the cell multiplexer / demultiplexer 310; And a control bus buffer (330) required for communication between the control unit (140) of the ATM layer processing PBA and the physical layer control unit (340). 3. The transmitting cell processor 130 checks whether the user cell buffer 131 and the management cell buffer 132 contain a cell to be transmitted to a subscriber, and determines the user cell 6 and the management cell 7. Read and multiplex, extract the VPI (Virtual Path Identifier) / VCI (Virtual Channel Identifier) of the cell to find out the connection identifier and send it to the sending cell management unit 134 (8), whether the connection is a virtual path connection or not A transmission connection identifier management unit 133 for transmitting the cell data 10 to the transmission cell management unit 134 together with a connection type 9 indicating whether the channel is connected or not; Read the connection management information using the connection identifier 8, the connection type 9 and the cell data 10 received by the transmission connection identifier management unit 133, and add an output PBA bitmap and line number to the front of the cell. And a transmission cell manager (134) for outputting a transmission cell (11) converted into 16 bits to a transmission cell bus (3). The method according to claim 2 or 4, wherein the transmission connection identifier management unit 133 checks whether the transmission connection identifier management circuit has a cell to be transmitted to the subscriber in the user cell buffer 131 and the management cell buffer 132. If there is a cell to be transmitted, a read signal is output to each buffer to read the cell, and the user cell 6 and the management cell 7 are multiplexed, and the VPI and VCI are extracted from the cell header to extract the virtual path connection identifier controller 133a. ₂ ) and a cell multiplexing unit 133a ₁ for transmitting to the connection identifier table management unit 133a ₃ ; When the VPI is received from the cell multiplexer 133a ₁ , the VPI is output to the virtual path connection identifier table 133b so that the virtual path connection identifier 11 of the corresponding VPI is read from the virtual path connection identifier table 133b. A virtual path connection identifier controller 133a ₂ which is transmitted to the table manager 133a ₃ ; And extracting the connection identifier 12 from the connection identifier table 133c by using the virtual path connection identifier 11 received by the virtual path connection identifier controller 133a ₂ and the VCI received from the cell multiplexer 133a ₁ . And a connection identifier table management unit 133a ₃ so that the transmission connection identifier management circuit 133a and the control unit 140 can read and write at the same time, and the virtual path connection identifier 11 is stored by the control unit 140. A virtual path connection identifier table 133b; And a connection identifier table (133c) in which the connection identifier output from the connection identifier table management unit (133a ₃ ) is registered. The VCI of claim 5, wherein the connection identifier table management unit 133a ₃ sets the VCI to 0 and outputs only the virtual path connection identifier 11 to the connection identifier table 133c in the case of a virtual path connection. DS1E subscriber matching device of an ATM switch characterized in that the connection identifier is found only by the virtual path connection identifier. The connection type bit 1 bit according to claim 5, wherein the virtual path connection identifier table 133b uses DPRAM and the virtual path connection identifier indicates whether the connection of the cell having the corresponding VPI is a virtual path connection or a virtual channel connection. And a 7-bit virtual path connection identifier and stored therein. 6. The device of claim 5, wherein the connection identifier table 133c is an element that checks whether input data matches data stored in the internal memory and outputs an address of a memory in which matching data is stored. DS1E subscriber matching device of an ATM switch, characterized in that CAM is used as a table to manage connection identifiers. The transmission cell management unit 134 of claim 4, wherein the transmission cell management circuit 134a indicates from the transmission connection identifier management unit 133 a connection identifier 8 and whether the corresponding connection is a virtual path connection or a virtual channel connection. type of connection (9) signal, the cell data 10, the cell data by receiving a signal or the like is transferred to the cell output unit (134a _2), and the remaining signals are cell input (134a ₁₎ to pass to the table control section (134a _3); A table control unit 134a _{3 which} reads connection information of the connection from the transmission cell management table 134b using the connection identifier 8; And a 16-bit cell in which the output PBA bitmap obtained from the connection information and the subscriber line number 3 bytes are added to the cell data received by the table control unit 134a ₃ and the cell input unit 134a ₁ , and converted into 16 bits. A cell output unit 134a ₂ for outputting the transmit cell 11 to the bus, and includes a transmit cell management table 134b connected to the connection identifier table manager 133a ₃ and having connection information for each connection. DS1E subscriber matching device of the ATM switch, characterized in that configured. 10. The transmission cell management table (134b) according to claim 9, wherein the transmission cell management table (134b) is composed of DPRAM for storing data, and an output PBA bit map 46, a subscriber line 47, and a header of an output cell to which cells of a corresponding connection should be output. The output cell header conversion request bit 52 indicating whether to convert the bit, the bit 53 indicating the connection type, and the type of the OAM cell generated when the OAM cell is generated, is generated as a single-to-end OAM cell or zone ( segment) A bit 54 indicating whether to generate an OAM cell, an output VPI 48, an output VCI 49, an output cell counter 50, an A bit 56 indicating whether the continuity check is enabled, a continuity check counter ( 51) DS1E subscriber matching device of an ATM switch, characterized in that consisting of.