KR0169906B1 - Multi-frame discriminating method for cell disassembler in atm network - Google Patents

Abstract

The present invention relates to a multi-frame by a cell decomposer that performs a function of converting data transmitted to an ATM cell into timeslot data in a matching device for accommodating existing PSTN number subscribers of an ATM switching system under development as a network node of a B-ISDN. A method of reading data, comprising: a time switch connection function of a cell decomposer for equal bit rate service, which simultaneously reads buffer data of a frame to be serviced next while performing buffer data read of one frame, and then reads next buffer data By reducing the number of times, stability is ensured for a larger number of channels. In addition, buffer data reads can be performed in multiple frames to reduce the number of buses used to ensure stability for a larger number of channels.

Description

Multiple Frame Reading Method of Cell Decomposer in ATM Networks

1 is a block diagram of a cell decomposer according to the present invention.

2 is a flowchart of a multi-frame reading of a cell resolver in an ATM network of the present invention.

* Explanation of symbols for main parts of the drawings

10 cell decomposition buffer 20 ATM connection

30: control memory 40: time switch connection portion

50: time switch matching unit

The present invention relates to a multiple frame reading method of a cell decomposer in an ATM network, and more particularly, to a cell decomposer for an identity bit rate service in an ATM network for accommodating existing PSTN subscribers of an ATM switching system under development as a network node of a B-ISDN. The present invention relates to a data frame reading method.

The time switch unit must continuously transmit one octet of data in one time slot time interval.

In order to perform this function, the conventional method refers to the data configuration of the control memory for each time slot time for the channel and link to be serviced, and reads the service data of the cell decomposition buffer of the corresponding frame and performs data service with the time switch unit. There is a method of providing data service using a time switch unit by reading service data of a cell decomposition buffer of two or consecutive channels.

However, the former method increases the bus usage time due to frequent control memory and decomposition buffer read / write use.

Accordingly, the number of serviceable channels is limited due to the limitation of the bus usage time, and there is a problem of requiring a fast operating speed of the control memory.

In addition, the latter method has a problem that can be effectively used only in limited cases, such as in the case of a multi-channel service.

Accordingly, in order to solve the above problems, the present invention reads service data of a cell decomposition buffer in a cell resolver for multiple frames of the same connection in an ATM network, partially performs a data service with a time switch unit, and the others serve the next service time. By reducing the number of reads of the control memory and the decomposition buffer, the purpose of the present invention is not only to increase the limit of the number of serviceable channels, but also to greatly alleviate the limitation on the operation speed of the control memory.

In order to achieve the above object, the present invention provides a time switch interface function of a cell decomposer for an equal bit rate service, wherein a frame to be serviced next is performed during an operation for reading buffer data of one frame. By reading the buffer data at the same time, the number of operations to read the next buffer data is reduced, which ensures stable operation for a larger number of channels.

In addition, buffer data reads are performed in multiple frames, thereby reducing the number of buses used, thereby ensuring stable operation of a larger number of channels.

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

In the embodiment of the present invention, a buffer data reading method will be described, taking the number of multiple frames as two frames.

1 is a block diagram of a cell breaker to which the present invention is applied. Looking at the configuration, the cell decomposition buffer 10 using a first-in first-out buffer (FIFO) to temporarily store the incoming ATM cell, and the ATM cell read through the cell decomposition buffer 10, the virtual path identifier / virtual ATM connection unit 20 for classifying each connection using a channel identifier (VPI / VCI), a control memory 30 for storing the address, control signal, and data which are separated and output through the ATM connection unit 20, and Time switch connecting portion 40 for reading ATM data stored in the control memory 30 according to the time slot (T / S) using a channel / link ID, and 8-bit parallel data to the time switch connection. It is composed of a time switch matching section 50 using a demultiplexer to convert and send in series.

Referring to the overall operation of the present invention by such a configuration as follows.

First, referring to the cell decomposition buffer write operation, an ATM cell received from an initial network is once stored in the cell decomposition buffer 10.

Receiving the signal that the cell is in the cell decomposition buffer 10, the ATM connection unit 20 sends a buffer read signal to the cell decomposition buffer 10 to read the cell synchronization signal and ATM data.

At this time, if the cell synchronization signal is valid, the VPI / VCI is extracted from the read data and the control data is read from the control memory 30.

Control data reads are performed twice, to perform multi-bit rate services.

The control data is used to determine the recording position of the cell decomposition buffer, and the data received from the network is recorded at the position.

When the control data is updated in the control memory 30 again after the writing is completed, the operation of the ATM connection unit 20 ends.

Next, a cell decomposition buffer read operation according to the present invention will be described.

The time switch matching section 50 performs a cell decomposition function of reading and servicing the data of the cell decomposition buffer 10 in response to a data request of the time switch connection section 50.

The control data of the control memory 30 is read with respect to the channel / link number received by the time switch connecting unit 40 to determine the location of the buffer in which the data to be serviced is stored.

At this time, the control data read is performed twice for the multi-bit rate service. After reading the buffer, a write operation occurs to update the control data again. Thus, the bus is used for three reads and one write operation. This is the biggest limiting factor for density and number of channels.

However, if one frame (125μs) of data using the same control data is prepared as proposed in the present invention, since only one frame of operation is sufficient for two frame time periods, more time is left in the data bus usage time. Is solved.

The time switch connecting unit 40 sends a channel and a link number to serve to the time switch matching unit 50, requests data, receives the requested data, converts the parallel data into serial, and transmits them in synchronization. .

In addition, the time switch connecting unit 40 receives a synchronous clock, generates a state signal necessary for operation, and sends the state signal to the ATM connecting unit 20 and the time switch matching unit 50.

2 is a multi-frame read flow diagram of the cell resolver of the present invention.

After reading and updating the control memory 30 of the even channel for the service request of the first even channel and the odd channel, the even channel data of the current frame and the next frame are read from the cell decomposition buffer.

Only the current frame data 2n is serviced at an even channel time, and the next frame data 2n is stored for service in the next frame.

In other words, only services for even channels are provided. At this time, the same procedure as before the read time is performed for the odd channel time. And it works the same way to the last channel.

After the first one frame, the next odd channel and even channel service process is repeated.

First, in the even channel service process, a service request of an even channel 2n and an odd channel is received from the time switch access unit 40 which is a multiplexer (S1).

After the control memory read and update (S2) by the even channel (2n) for this service request, the cell decomposition buffer 10 reads the even channel data (ch 2n, ch 2n) of the current frame and the next frame (S3). .

In the read even channel data, only the current frame data 2n is served at the even channel time, and the next frame data 2n is stored for serving in the next frame (S4).

Thereafter, it is determined whether the even-channel data read from the cell decomposition buffer is read first (S5), and if not the first reading, the odd-channel data (2n + 1) previously stored is serviced at odd-channel time (S6). .

Thereafter, the above process is performed until the last even channel (S7).

After this even channel service process is completed, the following odd channel service process is performed.

That is, referring to the odd channel service process, first, an even channel and an odd channel (2n + 1) service request are received from the time switch connector 40 (S8).

When the service request is received, the even channel data 2n of previously stored data is serviced (S9), and the control memory of the odd channel is read and updated (S10).

Subsequently, the odd channel data (ch 2n + 1 and ch 2n + 1) of the current frame and the next frame are simultaneously read from the cell decomposition buffer to serve only the current frame data (2n + 1) at odd channel time and the next frame data (2n +). 1) store for service in the next frame (S12).

That is, even channel data serves previously prepared data, and control memory reads, writes and cell decomposition buffer reads are performed only for odd frame data.

Then, the odd channel service process is repeated until the last channel S13.

By doing this, cell decomposition can be performed in multiple frames.

As described above, the present invention can increase the limit of the number of serviceable channels by halving the number of reads of the control memory and the decomposition buffer in the cell decomposer, and can greatly alleviate the limitation on the operation speed of the control memory.

Claims (3)

A method of reading multiple frames by a cell resolver having a time switch connection, a cell decomposition buffer, and a control memory in an ATM switch, the method comprising: reading buffer data of one frame to an even channel service request received from the time switch connection; After performing the even channel service process of simultaneously performing buffer data read of the next frame to be serviced, and performing the even channel service process, after performing buffer data read of one frame to the odd channel service request received from the time switch connection unit. An odd channel service process for simultaneously reading buffer data of a frame to be serviced and performing buffer data reading in multiple frames. The method of claim 1, wherein the even channel service process comprises receiving a service request of an even channel and an odd channel from the time switch connection unit, reading and updating a control memory of an even channel with respect to the service request; Reading the even channel data of the current frame and the next frame from the cell decomposition buffer, serving only the even channel data of the read current frame at the even channel time, and storing the even channel data of the next frame to serve in the next frame. And after the storage, if the data read from the cell decomposition buffer is not the first read, repeating the steps up to the last even channel after servicing the previously stored odd channel data in odd channel time. Multi-frame reading method of cell decomposer in ATM network. The method of claim 1, wherein the odd channel service process comprises the steps of: receiving a service request of an even channel and an odd channel from the time switch connection unit; serving data of an even channel previously stored at an even channel time; Performing the control memory read and update of the odd channel; and reading the odd channel data of the current frame and the next frame from the cell decomposition buffer to serve only the current frame data at odd channel time, and to serve the next frame data in the next frame. And repeating the above steps until the last odd channel after storing.