KR100284004B1 - Host Digital Terminal in Demand-Density Optical Subscriber Transmitter - Google Patents

Abstract

The present invention relates to a host digital terminal in a demand dense optical subscriber transmission device.

The host digital terminal according to the present invention has an ATM cell bus configured by dividing a predetermined number of uplink ATM cell buses and downlink ATM cell buses.

In addition, when each functional unit constituting the host digital terminal of the present invention attempts to send a predetermined ATM cell to an ATM cell bus, the functional unit may receive an ATM cell after changing the virtual path identifier (VPI) value of the ATM cell to the corresponding value. It is configured to send the address and port number of a predetermined functional unit together.If you want to receive an ATM cell from the ATM cell bus, compare the address sent with the ATM cell with your own address and receive the corresponding ATM cell. It is configured to output this ATM cell to the corresponding port.

Description

A Host Digital Terminal for Fiber Loop Carrier-Curb Systems

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a host digital terminal in a demand-density optical subscriber transmission device. In particular, an ATM cell bus, which is a passage through which an asynchronous transfer mode cell (hereinafter referred to as an ATM cell) flows, is connected to an uplink bus. The present invention relates to a host digital terminal (HDT) in a high-density optical subscriber transmission device (FLC-C system) having a structure separated by a downlink bus.

Conventionally, as the use of voice information and a computer has become common, an integrated services digital network (ISDN) using a digital communication method has been proposed and used as a method of integrating and communicating data information. Although coaxial cable has been used, coaxial cable has a problem in that it is not possible to secure a bandwidth required for high-speed data communication or image information communication, which is rapidly expanding demand.

As a solution to this problem, optical communication methods have been devised and used, and optical communication networks have been extended to all sections of the communication section. A device that realizes this is a demand dense optical subscriber transmission device.

1 is a block diagram of a demand-intensive optical subscriber transmission apparatus 200, the demand-intensive optical subscriber transmission apparatus 200 is a service transmission platform of the FTTC (Fiber To The Curb) method, home-shopping, games, movies The service providers 130 that provide various services, such as the host digital terminal 210 and the optical termination device 220, which constitute the ATM switch 100 and the demand dense optical subscriber transmitter 200. A service is provided to subscribers 140 through a network unit.

Here, the host digital terminal (HDT: 210), which is a component of the demand-density optical subscriber transmitter 200, is a device installed in a telephone station, and connects DS1 and DS1E signals to ATM-based broadband signals transmitted from the broadband switching network. After the integration-multiplexing with the synchronous digital hierarchy, the optical transmission to the ONU 220 as a power device and its reverse function are performed.

The host digital terminal (HDT: 210) includes an ATM transmit / receive unit (211,212: ATM Transmit Receive Unit), an ATM cell bus 213, an optical transmit / receive unit (214: Optical Transmit Receive Unit), a predetermined public It is composed of a DS1E processing unit 215 and a main control unit 216, which are connected to a telephone network PSTN and exchange DS1E level signals.

At this time, two ATM transceiver units 211 and 212 are mounted on one host digital terminal (HDT) 210, and four synchronous transport module signals STM-1: each having a transmission rate of 155.52 Mbps from the ATM switch 100; After receiving the Synchronous Transport Module-1, processing the overhead included in the synchronous transport module signal STM-1, extracting the ATM cell and sending it to the ATM cell bus 213 or vice versa. . That is, the ATM transceiver units 211 and 212 have four STM-1 ports.

The optical transmission / reception unit 214 is composed of eight, and one optical transmission / reception unit 214 is connected to two optical termination units 220 (ONU), thereby connecting a total of 16 optical termination units (ONU). The optical transmission / reception unit 214 receives ATM cells through the ATM cell bus 213 to make an STM-4 class optical signal (622.08Mbps) and transmits the same to the optical termination unit 220 (ONU) or performs the reverse function. .

The DS1E processing unit 215 receives a DS1E signal from a public switched telephone network (PSTN) or a dedicated network, maps it to an ATM payload space, and then sends it to the optical transmission / reception unit 214 through an ATM cell bus 213. It performs the sending function and its reverse function.

The Main Control Unit (216) is an Operation Administration and Maintenance Cell (hereinafter referred to as an OAM cell) to be processed by itself among ATM cells through the ATM cell bus 213. Receives and processes the data, and is responsible for the overall control of the host digital terminal (HDT) 210 by exchanging IPC (Inter-Processor Communication) messages with each component.

In addition, the optical termination unit 220 (ONU) is installed in a distribution center in a dense residential area such as an apartment complex to separate the subscriber signal from the STM-4 class optical signal received from the host digital terminal (HDT: 210) according to the service. It is a device that performs the function provided to each subscriber and its reverse function.

2 is a diagram of a conventional ATM cell bus connection, showing a state in which the ATM transceiver units 211 and 212 and the optical transceiver unit 214 are connected via an ATM cell bus 213.

As shown in FIG. 2, the ATM cell bus 213 used in the conventional host digital terminal (HDT) 210 uses a separate bus for every four synchronous transport module signals (STM-1), so a total of four independent buses are provided. It is composed of a structure, and each bus is commonly used for up and down.

In order to use such a bus structure, a commercial chip (CUBIT) must be used as the number of buses for each functional element as a cell bus switching element performing an ATM cell bus connection function. In addition, a functional unit such as the optical transmission / reception unit 214 used a multiplexing / demultiplexer for connecting STM-4 class ATM cell signals to each cell bus switching element (CUBIT Chip).

Therefore, the cost of configuring the host digital terminal (HDT: 210) is increased due to the use of multiple chips with overlapping functions and high power consumption, and in particular, the use of commercial chips can improve the function of the host digital terminal (HDT: 210). It does not flexibly cope with the necessity, and there are various problems such as unnecessary use of commercial chips as they are not used without commercial chips.

Accordingly, the present invention has been made to solve the above problems, ATM cell bus is divided into an uplink bus and a downlink bus, and each functional unit can perform a cell bus connection function without using a commercial chip (CUBIT) It is an object of the present invention to provide a host digital terminal in a demand-density optical subscriber transmission device configured to be capable of performing the above operation.

In order to achieve the above object, the host digital terminal in the demand-density optical subscriber transmission device according to the present invention, the ATM cell bus of the host digital terminal is divided into a predetermined number of up ATM cell bus and down ATM cell bus In addition, predetermined function units of the host digital terminal receive an ATM cell after changing a virtual path identifier (VPI) value of the ATM cell to a corresponding value when a predetermined ATM cell is to be sent to the ATM cell bus. It is configured to send an address and a port number of a predetermined unit together, and when receiving an ATM cell from the ATM cell bus, compares the address transmitted with the ATM cell with its own address and receives the corresponding ATM cell. And outputting this ATM cell to a port corresponding to the port number.

1 is a block diagram of a demand-density optical subscriber transmission device,

2 is a conventional ATM cell bus connection diagram;

3 is a configuration diagram of a host digital terminal (HDT) according to the present invention;

4 is a connection diagram between an ATRU and an OTRU.

* Explanation of symbols for main parts of the drawings

100: ATM exchanger 200: demand dense optical subscriber transmission device

210: host digital terminal (HDT) 211, 212: ATM transmit / receive unit (ATRU)

213: ATM cell bus 214: optical transceiver unit (OTRU)

215: DS1E processing unit 220: optical termination unit (ONU)

310,430: address translation and routing header processing unit

320, 420: pre-input-line output unit 330, 410: cell router unit

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

3 is a block diagram of a host digital terminal (HDT) 210 according to the present invention, and each functional unit is connected to an ATM cell bus 213 divided into an uplink bus and a downlink bus. Hereinafter, for convenience of description, the direction toward the ATM switch 100 will be referred to as an upward direction, and the direction toward the optical termination device 220 (ONU) will be referred to as a downward direction.

The host digital terminal (HDT) 210 of the present invention includes two ATM cell buses (first uplink bus and second uplink bus) through which upstream ATM cells flow, and two ATM cell buses (first downlink) through which downlink ATM cells flow. Bus, a second downlink bus).

At this time, since the two ATM transceiver units 211 and 212 and the eight optical transceiver units 214 each have four STM-1 ports, two STM-1 ports are connected to the first uplink bus and the first downlink bus. The remaining two STM-1 ports are connected to the second uplink bus and the second downlink bus.

The DS1E processing unit 215 and one main control unit 216 are connected to the first uplink bus and the first downlink bus, and the DS1E processing unit 215 is connected to one optical transceiver unit 214 and one to one. Connect to correspond.

In addition, the bus arbiter for the downlink ATM cell bus is in charge of the first optical transceiver and, if an error occurs in the first optical transceiver, the second optical transceiver. In addition, the first ATM transceiver unit 211 serves as a bus arbiter for the uplink ATM cell bus, and if an error occurs in the first ATM transceiver unit 211, the second ATM transceiver unit 212 is used. ) Acts as a bus arbiter.

On the other hand, the functional units of the host digital terminal (HDT) 210 according to the present invention, that is, the ATM transmission and reception units 211 and 212, the optical transmission and reception unit 214, the DS1E processing unit 215, and the main control unit 216 It is configured to connect with the ATM cell bus 213 as follows.

That is, among the functional units of the host digital terminal (HDT: 210), the functional unit to send a predetermined ATM cell to the ATM cell bus 213 stores the virtual path identifier (VPI) value of the ATM cell. After changing to the corresponding value, it is configured to send the address of the functional unit to receive this ATM cell together with the port number to be output from this functional unit.

In addition, the functional unit that wants to receive the ATM cell from the ATM cell bus 213 receives the address and port number of the functional unit transmitted with the ATM cell, compares it with its own address, confirms that it is an ATM cell, and then sends the corresponding cell. It receives an ATM cell and is configured to output this ATM cell to a port corresponding to a port number.

4 is a connection diagram of the first ATM transceiver unit 211 and one of the optical transceiver units 214 (the first optical transceiver unit 400), detailing the connection of the respective functional units via the ATM cell bus 213. An embodiment for explanation. At this time, it is assumed that the first optical transmission / reception unit 400 is connected to the first optical termination unit 221 (ONU) and the second optical termination unit 222 (ONU), among the sixteen optical termination units ONU.

First, the data transfer process in the downward direction will be described.

The STM-4 class optical signal input from the ATM switch 100 to the four STM-1 ports of the first ATM transceiver unit 211 of the host digital terminal (HDT: 210) is a synchronous transport module signal (STM-) in the form of an electrical signal. 1) After conversion to four, each synchronous transport module signal (STM-1) is processed into a signal (RxD1, RxD2, RxD3, RxD4) in units of ATM cells.

These signals RxD1, RxD2, RxD3, and RxD4 are respectively input to the address translation and routing header processor 310 for transmission to any one of eight corresponding optical transmission / reception units 214.

The address translation and routing header processor 310 reads the value of the virtual path identifier (VPI) from the input ATM signals RxD1, RxD2, RxD3, and RxD4, and changes the value to a virtual path identifier (VPI) of the set path. Pre-input-line output unit 320 with routing header information including an address of the first optical transceiver unit 400 as a destination and a port number at which the corresponding ATM cell is output from the first optical transceiver unit 400. Write to the corresponding FIFO element of).

At this time, each of the FIFO elements RP1-A, RP2-A, RP3-A, and RP4-A of the pre-input-output unit 320 correspond one-to-one with each STM-1 port.

Then, the cell router 330 reads the data stored in each FIFO element of the pre-input-output unit 320 and outputs the data to the corresponding downlink bus of the ATM cell bus 213. That is, the data in RP1-A and RP2-A among the FIFO elements of the pre-input / output unit 320 are output to the first down bus, and the data in RP3-A and RP4-A are output to the second down bus. Is output.

Meanwhile, the cell router 410 of the first optical transceiver unit 400 receives an ATM cell from the downlink bus and checks header error check (HEC) information of the received ATM cell to determine whether the received ATM cell is in error. Also, it checks whether the address information received with the ATM cell and the address assigned to it match and pass the ATM cell to the pre-input-output unit 420 or discard it.

When writing the ATM cell received from the corresponding ATM cell bus to the pre-input-output unit 420, the port number received together with the corresponding ATM cell is referred to. In other words, when the port number has a logical value of '0', it is written as RP1-O or RP2-O among the FIFO elements of the pre-input / output unit 420, and RP3 when the port number has a logical value of '1'. Write to -O or RP4-O. Therefore, even an ATM cell received through the second downlink bus can be written to RP2-O.

Then, after reading the data of the pre-input-line output unit 420 in the address translation and routing header processing unit 430 of the first optical transceiver unit 400, the header check order (HCS) information is added and output. These data are again converted into STM-4 class signals and transmitted to the first optical terminator 221 (ONU) or the second optical terminator 222 (ONU).

That is, the data in the RP1-O and RP2-O of the pre-input-output unit 420 are transmitted to the first optical terminator 221 (ONU), and the data in the RP3-O and RP4-O are second. To the optical termination device 222 (ONU).

Now, the data transfer process in the upward direction will be described.

After receiving the STM-4 level signal from the first optical terminator 221 or the second optical terminator 222 through the optical path, the first optical transceiving unit 400 converts the optical signal into an electrical signal, and then ATM The signal is converted into a cell unit and output.

The address translation and routing header processing unit 430 of the first optical transmission / reception unit 400 receives a signal of this ATM unit, and at the address of the corresponding ATM transmission / reception unit 211 or 212 and the corresponding ATM transmission / reception unit 211 or 212. The ATM cell is written to the pre-input-output unit 420 together with the routing header consisting of the port number to be output.

At this time, the cells to be output to the first STM-1 port and the second STM-1 port of the four STM-1 ports of the corresponding ATM transceiver unit 211 or 212 are the FIFO element of the pre-input-output unit 420. The cells to be output to the third STM-1 port and the fourth STM-1 port are written to the TP3-O or TP4-0.

Then, the cell router 410 of the first optical transceiver unit 400 reads the data of the pre-input-pre-output unit 420 and sends the data to the uplink bus of the ATM cell bus 213.

The cell router 330 of the first ATM transmitting / receiving unit 211 receives an ATM cell and a routing header from a corresponding uplink bus, and compares an address value with its own address value among routing header information and receives an ATM cell sent to it. Then, it is written as a FIFO element of the pre-input-line output unit 320 corresponding to the port number.

At this time, selecting the corresponding FIFO element from the pre-input / out-output unit 320 determines which of four STM-1 ports of the first ATM transceiver unit 211 is to be output. That is, since the first optical transmission / reception unit 400 separates the first uplink bus and the second uplink bus, the cell router 330 determines which of the first port and the second port is output. It is written as TP1-A or TP2-A of the pre-input-line output unit 320, and it is determined as which port is output from the third port and the fourth port, and is written as TP3-A or TP4-A.

Then, the address translation and routing header processor 310 of the first ATM transceiver unit 211 reads the data from the pre-input-output unit 320 and outputs the data in units of ATM cells, each of which is STM-1. Each port is made of a synchronous transport module signal (STM-1) and transmitted to the ATM switch 100.

As described above, according to the present invention, a host digital terminal (HDT) 210 may be implemented without using commercial chips (CUBITs) and multiplexing / demultiplexing devices used for switching the ATM cell bus 213. Therefore, the flexibility of the configuration of the host digital terminal (HDT: 210) is improved, and the cost can be reduced and the structure can be simplified when manufacturing each functional unit.

Claims (1)

In configuring a host digital terminal of a predetermined demand-density optical subscriber transmitter, the ATM cell bus of the host digital terminal is divided into a predetermined number of uplink ATM cell buses and downlink ATM cell buses, The predetermined functional units of the host digital terminal change the virtual path identifier (VPI) value of the ATM cell to the corresponding value when the predetermined ATM cell is to be sent to the ATM cell bus, and then the address of the predetermined functional unit to receive the ATM cell. And send the port number together, When receiving an ATM cell from the ATM cell bus, comparing the address transmitted with the ATM cell with its own address, receiving the corresponding ATM cell, and outputting the ATM cell to a port corresponding to the port number. A host digital terminal in a demand-density optical subscriber transmitter.