KR19990080597A - Data Transmission Method at Subscriber of Asynchronous Transfer Mode Switch - Google Patents

Abstract

As a method of processing a transmit / receive cell at a subscriber part of an asynchronous transmission mode switch, when a cell is transmitted from the subscriber to the routing tag processor through the physical layer processor, the virtual path indicator and the virtual channel indicator are inspected to insert a routing tag. A step of transmitting to the line connection, a checking step of checking whether the cell is a non-constant rate cell when the cell is received at the trunk-line connection, and setting a cell segment bit in the case of the non-constant rate cell, Resetting the bits, replacing the priority bits and the cell division bits after setting the cell division bits, and transmitting them to the switch module connection unit; and inserting dummy data at the switch module connection unit and transmitting the dummy data to the switch module.

When a cell is received from the switch module to the switch module connection, the receiving cell processing removes dummy data and transmits the data to the trunk-line connection, and replaces the cell classification bit and priority bit of the cell received at the trunk-line connection. And deleting the routing tag of the received cell and transmitting the received routing tag to the subscriber through the physical layer processing unit.

Description

Data Transmission Method at Subscriber of Asynchronous Transfer Mode Switch

The present invention relates to a data transmission method in a subscriber board of an asynchronous transmission mode switching system, and more particularly, to a method of changing a weight of data using a routing tag and transmitting the same.

In general, an asynchronous transfer mode switching system was developed to process and transmit data at high speed. Therefore, the asynchronous transmission mode switching system transmits data mainly on a constant bit rate (CBR) like real time data. However, in recent years, the service of data having Unspecified Bit Rate (UBR) such as E-Mail has been accepted. Since a data service having a constant rate and a data service having a constant rate are simultaneously performed, when a congestion occurs in the asynchronous transmission mode switching system, the received cell priority bit (CLP: Cell Loss Priority) is examined. Discard the low priority cell.

However, since both data having a constant rate and data having a rate have a priority bit of a cell, the switching module of the asynchronous transmission mode switching system does not distinguish between the cell having the constant rate and the cell having the constant rate. It will only be discarded according to its priority. Therefore, when a cell of a constant rate service such as a real-time service is discarded, the quality of service becomes worse than that of a non- constant rate cell.

Accordingly, an object of the present invention is to provide a method of improving the quality of service by preventing the disposal of cells having a constant rate as much as possible.

Another object of the present invention is to provide a method for transmitting a cell having a constant rate by giving a higher priority than a cell having a constant rate.

The present invention for achieving the above object is a method for processing a transmit / receive cell at a subscriber part of an asynchronous transmission mode switch, wherein the transmission cell processing is a virtual path indicator and a virtual channel when the cell is received from the subscriber to the routing tag processor through the physical layer processor. Inserting a routing tag and transmitting the routing tag to the trunk-line connection unit; and checking whether the cell is a non-constant rate cell when the cell is received at the trunk-line connection unit; Resetting a cell division bit in the case of a constant rate cell, replacing the priority bit and the cell division bit, and transmitting it to the switch module connection unit after setting the cell division bit; Inserting the dummy data and transmitting the dummy data to the switch module,

Receiving a cell process when the cell is received from the switch module to the switch module connection unit and removing the dummy data and transmitting to the trunk-line connection unit, the cell identification bit of the cell received at the trunk-line connection unit And substituting the priority bits and transmitting the subscriber station through the physical layer processor by deleting the routing tag of the received cell.

1 is a block diagram of a subscriber board in an asynchronous transfer mode switching system to which the present invention is applied;

2A and 2B show routing tags and 1: multiple routing tags in a 1: 1 connection.

3 is a flow chart of operation in the transmission of a cell received from a subscriber in accordance with the present invention.

4 is a flowchart illustrating an operation of transmitting a cell that is switched and received by a subscriber unit according to the present invention.

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

1 is a block diagram of a subscriber board in an asynchronous transfer mode switching system to which the present invention is applied.

The physical layer processor 100 transmits the cell to the routing tag inserter 110 when the cell is received from the subscriber, and transmits the cell to the subscriber when the cell is received from the trunk-line access unit 120. The routing tag inserter 110 includes a routing table for switching, and checks a virtual path indicator (VPI) and a virtual channel indicator (VCI) of the received cell and inserts a 3-byte routing tag into the received cell. . Routing tags inserted in the cell to be transmitted are classified into two types according to the transmission scheme. First, there is a 1: 1 connection (Point to Point) in which a cell is transmitted from one subscriber to another and a 1: point to multi-point connection in which a cell is transmitted from one subscriber to a plurality of other subscribers. Therefore, routing tags inserted according to the above connection method are illustrated in FIGS. 2A and 2B.

FIG. 2A illustrates a routing tag in a 1: 1 connection currently applied to a system, and FIG. 2B also illustrates a 1: multiple routing tag used in a current system.

Referring to FIGS. 2A and 2B, the fifth bit of zero octets and the sixth and seventh bits of one octet are bits that are not commonly used. Accordingly, in the present invention, the priority of the cell may be determined using the fifth bit of the zero octet of the routing tag and the sixth and seventh bits of the one octet. In the following description, the fifth bit of zero octets is used for clarity. In addition, bits that classify priorities according to cell types are referred to as 'cell classification bits'.

The trunk-line connection unit 120 is set to 1 in the case of the constant rate cell according to the cell type in the cell division bit, which is the fifth bit of the 0 octet, in the cell received with the routing tag inserted in the routing tag insertion unit 110. Set to 0 for rate cells. In addition, the cell classification bit is replaced with a priority bit (CLP) and transmitted to the switch module connection unit 130. Therefore, since the cell classification bit and the priority bit are replaced, the cell classification bit according to the present invention is stored in the actual priority bit.

The switch module connection unit 130 is connected to a switching module (S / W module), and loads 8 bytes of dummy data in a cell received from the trunk-line connection unit 120 and outputs the dummy data to the switch module. In this case, the 8-byte dummy data is inserted in the switch module connection unit 130 in units of 64 bytes. In addition, the dummy data of the cell received from the switch module is removed and output to the trunk line connection unit 120. Finally, the switch module switches the input cell to the routing tag. When the cell congestion occurs, the switch module checks the priority bit and discards the cell, and performs switching.

3 is a flowchart illustrating the operation of transmitting a cell received from a subscriber according to the present invention.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3.

In step 200, the routing tag inserter 110 checks whether a cell is inserted from the physical layer processor 100. When the check result cell is inserted, the routing tag insertion unit 110 reads the virtual path indicator (VPI) and the virtual channel indicator (VCI) from the inserted cell in step 202. The routing tag insertion unit 110 searches for the routing table and inserts a routing tag through the read virtual path indicator and the virtual channel indicator in step 204. In addition, the routing tag insertion unit 110 inserts a routing tag into the incoming cell in step 206 and outputs the routing tag to the trunk line connection unit 120. When the cell is inserted from the routing tag insertion unit 110, the trunk-line connection unit 120 checks whether the input cell is a specific rate cell in step 208. The trunk-line connecting unit 120 proceeds to step 210 in the case of the non-constant rate cell as a result of the inspection, and proceeds to step 212 in the case of the constant rate cell.

When the trunk-line connection unit 120 proceeds to step 210 in step 208, the trunk-line access unit 120 sets a cell division bit to 1 in the routing tag of the received cell and proceeds to step 214. In contrast, if the trunk-line connection unit 120 proceeds from step 208 to step 212, the trunk-line access unit 120 sets the cell division bit to 0 in the routing tag of the received cell and proceeds to step 214. The trunk line connection unit 120 transmits the priority bit of the received cell and the cell classification bit to the switch module connection unit 130 in step 214 and proceeds to step 216. The switch module connection unit 130 inserts dummy data for a switching operation into the received cell in step 216 and transmits the dummy data to the switch module in step 218. Accordingly, the switch module performs a switching operation according to the routing tag of the input cell. When a cell congestion occurs, the switch module searches for a priority bit and discards a cell having a lower priority.

4 is a flowchart illustrating operations during cell transmission that is switched and received by the subscriber unit according to the present invention.

Hereinafter, an operation of cell transmission according to the present invention will be described in detail with reference to FIGS. 1 to 4. The switch module connection unit 130 is switched without being discarded by the switch module in step 300 to check whether the cell is drawn from the switch module. The switch module connection unit 130 proceeds to step 302 and removes the dummy data of the inserted cell when the check result cell is inserted. In operation 304, the switch module connection unit 130 transmits the cell from which the dummy data is deleted to the trunk line connection unit 120. The trunk line connection unit 120 replaces the cell division bit and the priority bit of the received cell and proceeds to step 308. Thus, the switched and transmitted cell to the subscriber is returned to the form of the cell before being transmitted. If the trunk-line connection unit 120 proceeds from step 306 to step 308, the trunk-line connection unit 120 removes the routing tag of the received cell, and proceeds to step 310 and transmits the cell from which the routing tag has been removed to the physical layer processor 100.

As described above, the cell division bit is inserted, the priority bit and the cell division bit are replaced, and transmitted to the switch module, thereby causing the switch module to discard the non-constant rate cell before the constant rate cell when the cell is discarded. The benefits are to improve the quality of service.

Claims (5)

In the subscriber data transmission method of the asynchronous transfer mode switch, When the cell is received from the subscriber at the routing tag insertion unit, inspecting the virtual path indicator and the virtual channel indicator, inserting routing tags and transmitting them to the trunk-line connection; A check step of checking whether a cell is at a constant rate rate when the cell is received at the trunk line connection; Resetting the cell classification bit in the case of the constant rate cell, and resetting the cell classification bit in the case of the constant rate cell; Transferring the priority bit and the cell classification bit to the switch module connection unit after setting the cell classification bit; And inserting dummy data from the switch module connection unit and transmitting the dummy data to the switch module. The method of claim 1, wherein the cell classification bit, And a bit which is not commonly used for 1: 1 connection and 1: multiple connection in the routing tag. In the subscriber cell processing method of the asynchronous transmission mode switch, Removing dummy data when the cell is received from the switch module to the switch module connection, and transmitting the dummy data to the trunk line connection; Replacing cell division bits and priority bits of a cell received at the trunk-line connection; And deleting the received routing tag of the cell and transmitting the received routing tag to a subscriber through a physical layer processor. In the subscriber station of the asynchronous transmission mode switch, Receiving a cell from the subscriber to the routing tag processing unit through the physical layer processing unit, inspecting the virtual path indicator and the virtual channel indicator, inserting a routing tag and transmitting the inserted routing tag to the trunk-line connection unit; A check step of checking whether a cell is at a constant rate rate when the cell is received at the trunk line connection; Resetting the cell classification bit in the case of the constant rate cell, and resetting the cell classification bit in the case of the constant rate cell; Transferring the priority bit and the cell classification bit to the switch module connection unit after setting the cell classification bit; A transmission cell processing step of inserting dummy data in the switch module connection unit and transmitting the dummy data to the switch module; Removing the dummy data and transmitting the dummy data to the trunk-line connection when the cell is received from the switch module to the switch module connection; Replacing the cell classification bit and the priority bit of the cell received at the trunk-line connection; And deleting the routing tag of the received cell and transmitting it to the subscriber through the physical layer processing unit. The method of claim 4, wherein the cell classification bit, And a bit which is not commonly used for 1: 1 connection and 1: multiple connection in the routing tag.