KR0150749B1 - Atm cell processing method for point to multi-connection - Google Patents

Abstract

The present invention relates to an ATM cell processing method for a one-to-multiple connection in a centralized broadband network termination device, and an ATM cell processing method for a one-to-multiple connection applied to a centralized broadband network termination device of a broadband integrated information communication network. In step 1, when a cell is input, a first step of checking whether a cell is registered in a lookup table by inserting a connection identifier into the HEC field, extracting only a header of a cell, and comparing it with a previously set transformation header value for each cell ( 200 to 203); A second step (204, 205) of discarding the cell if it is not a cell registered in the lookup table in the first step (200 to 203) and checking whether it is an internal communication cell if the cell is registered; And a third step 206 of inserting 0x3x into the HEC if the cell is not an internal communication in the second step 204 and 205 and inserting 0x0x into the HEC if the cell is an internal communication and transmitting it to the transmitting cell processor 3 18 (206). 209 to 209, a fourth step (300, 301) of determining whether the cell for the internal communication when the cell is input; A fifth step (302 to 304) in which the fourth step (300, 301) inserts 0xc0 in the HEC if the cell is not an internal communication and inserts 0x0x in the HEC in the internal communication cell and multiplexes the multiplexing by inserting 0x0x in the HEC; In the fifth step 302 to 304, if the cell copy is not one-to-one connection, the cell is routed and transmitted to all the buffers. If the one-to-one connection is performed, the cell is transmitted by routing the cell to the corresponding buffer. Multiplexing is first performed in a small subscriber device such as a converged network termination device, including a receiving step consisting of a sixth step (305 to 308) for inserting a connection identifier and outputting it to a corresponding port. There is an effect that can perform one-to-multiple and broadcast connection functions without addition.

Description

How to handle ATM cells for one-to-multiple connections

1 is a block diagram of an ATM cell processing apparatus to which the present invention is applied.

2 is a cell format configuration diagram according to an embodiment of the present invention.

3 is a block diagram of a connection recognizer according to an embodiment of the present invention.

4 is a flow chart according to one embodiment of the invention.

The present invention relates to a method for processing ATM cells for one-to-one as well as one-to-one multiplex and broadcast connection using a HEC (Header Error Control) field in a centralized broadband network termination device (B-NT) constituting a broadband integrated information communication network. .

As communication technology develops, users demand a variety of high-quality services, and services such as high-speed data services such as file transfer and real-time video services with variable bit rates, as well as continuous services such as voice and video services. In order to provide the over the same link, ATM broadband broadband network (B-ISDN) has emerged.

Services such as on-demand video services and three-way calls required by users in a B-ISDN environment are only available within devices that support one-to-multiple connections.In order to support one-to-multiple connections, multiple copies of the same cell at the ATM layer The function of inserting other connection information into the ATM cell header is required. Conventionally, an ATM layer protocol processing apparatus is placed in front of a switch or an ATM multiplexer, and a method of inserting a transform header for each link individually in a cell copied from the multiplexer has been used. The above method has the advantage of not limiting the bandwidth available in one-to-multiple connections, but it is not suitable due to the large amount of hardware to be applied to small subscriber devices such as network termination devices because hardware for converting headers is required for each link. There is a problem.

The present invention devised to solve the problems of the prior art as described above, the HEC field present in the cell header in the centralized network termination device is referred to as the physical layer port identifier and one-to-multiple connection identifier (hereinafter referred to as 'connection identifier') It is an object of the present invention to provide an ATM cell processing method for performing one-to-multiple connection and broadcast type connection without adding additional hardware in a structure in which multiplexing is performed first.

In order to achieve the above object, the present invention provides a method for processing an ATM cell for one-to-multiple connection, which is applied to a centralized broadband network termination (B-NT) device of a broadband integrated information communication network. A first step of checking whether each of the cells is a cell registered in the lookup table by extracting only the header of the cell and inserting the linkage identifier into the HEC field and comparing the cell header with a previously set transform hair value; A second step of recognizing an incorrect insertion cell if not a cell registered in the lookup table in the first step and discarding the cell; And a third step of inserting and outputting 0x3x into the HEC if the cell is not an internal communication cell in the second step, and inserting 0x0x into the HEC and transmitting the cell to the transmitting cell processor 3 if the internal communication cell is input. Determining whether the cell is an internal communication cell; A fifth step of inserting 0xc0 into the HEC if the cell is not an internal communication cell and inserting 0x0x into the HEC if the internal communication cell is multiplexed to determine whether the connection is one-to-one; In the fifth step, if the cell is not one-to-one connection, the cell is copied and transmitted to all the buffers. If the cell is one-to-one connection, the cell is routed and transmitted to the corresponding buffer, and then a connection identifier is inserted to perform one-to-multiple. And a receiving step comprising a sixth step of outputting the corresponding port.

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

1 is a block diagram of an ATM cell processing apparatus to which the present invention is applied, and is composed of a combination of four ATM layer function processors 11, 14, 17, and 110, and the ATM layer function processors 11, 14, 17, and 110 A header of an ATM cell transmitted from a transmitting cell processor (12, 15, 18, 111) and the transmitting cell processor (13, 16, 19, 111) inserting a connection identifier into the HEC field and multiplexing the ATM cell transmitted from the physical layer. VPI / VCI + connection identifier) is composed of the receiving cell processing unit (13, 16, 19, 112) and a plurality of buffers to be extracted and compared, exchanged with a predetermined translation header value and routed.

When the ATM layer function processor 1 (11) receives a cell from each port of the physical layer, the transmitting cell processor 1 (12) inserts a connection identifier corresponding to the identifier of each port into the HEC field. The cell inputted from port 1 is stored in buffer 114 and 0x00 is inserted into the HEC field. The cell inputted from port 2 is stored in buffer 115 and 0x01 is stored, and the cell inputted from port 3 is buffered 116. 0x02 and cells inputted from port 4 are stored in the buffer 117, and then 0x03 is inserted and transmitted to the receiving cell processor 1 (13), and the receiving cell processor 1 (13) is virtual in the header. The path, virtual channel identifier (VPI / VCI) and connection identifier are extracted and compared with the value set in the lookup table inside the receiving cell processor 1 (13). If the same value, the transmitting cell of the ATM layer function processor 2 (14). Routing to processing unit 2 (15), if the comparison value is different from the preset value is recognized as a cell that is incorrectly inserted and discarded. The transmitting cell processing unit 2 (15) of the ATM layer function processor (2) 14 recognizes that the cell transmitted from the receiving cell processing unit 1 (13) is a network-directed cell and inserts 0x3x into the HEC field. When the data is input through the buffer 126, it is recognized as an internal communication cell and 0x0x is inserted. The lower two bits maintain a value in the ATM layer function processor 1 (11) to distinguish each subscriber and to support multiple connections between the network and each subscriber. Copy the cell to 15). If the cell transmitted to the receiving cell processor 2 (16) is compared with the value set in the lookup table and the value extracted from the header, the header is replaced with a preset converted header value, and then the network is routed to the buffer 130 for physical transmission. The packet is transmitted to the layer port 5, and the internal communication cell is routed to the buffer 132 and transmitted to the transmitting cell processor 3 (18).

The transmitting cell processor 3 18 of the ATM layer function processor 3 17 recognizes the cell transferred to the buffer 133 as an internal communication cell and distinguishes the cell transferred from the network from the internal communication cell, and inserts 0x0x into the HEC field. The cell delivered to the buffer 134 is inserted into 0xc0 and transmitted to the receiving cell processor 3 (19). The receiving cell processing unit 3 (19) copies the cell transmitted from the transmitting cell processing unit 3 (18) to each buffer. The cell to be transmitted to the physical layer port 1 is the buffer 138, the port 2 is the buffer 139, Port 3 copies the buffer 140 and port 4 to the buffer 141 to deliver the cell only to each corresponding buffer for one-to-one connection, and simultaneously transfers the cell to all corresponding buffers for one-to-multiple connection and broadcast connection. Copy and support. The cell copied by the above is transmitted to the transmitting cell processor 4111 of the ATM layer function processor 4110, and when the cell is input to the buffer 143, 00 is inserted into the 6th and 5th bits, and the buffer ( Recognizing that the bit is transmitted to port 2 when the data is input to 144, the bit is set to 01, and recognizing that the bit is output to the port 3 when input to the buffer 145, to 10, and to port 4 when it is input to the buffer 146. Recognized as being outputted to each of the 11 and inserts after the transfer to the receiving cell processor 4 (112) of the ATM layer function processor 4 (110). The receiving cell processor 4 112 compares the transmitted cell with a value set in a lookup table and replaces it with a preset conversion header if the same value is transmitted, and transmits it to a corresponding port of the physical layer.

In the ATM cell processing method according to the present invention, for example, a multi-connection support scheme may be input to a cell in which VPI / VCI is 0/32 in physical layer port 1 and 0/33 in physical layer port 3, respectively. Layer port 4 is transmitted as a connection value of 0/34, and in the physical layer port 2, the cell having the VPI / VCI is 0/32 is inputted, so that the physical layer port 1 is 0/35, and the physical layer port 4 is 0/36. Suppose it is passed by value.

First, the cell transmitted from the port 1 is stored in the buffer 114, and then has the header of VPI / VCI = 0/32 and HEC = 0x00 by the transmitting cell processor 1 (12). The cell entered at port 2 is delivered with a header of VPI / VCI = 0/32 and HEC = 0x01. Since the cell transmitted from each port is an internal communication cell, the receiving cell processing unit 1 (13) routes the buffer 121 to the transmitting cell processing unit 2 (15), and the transmitting cell processing unit 2 (15) transmits two cells. Transfers to the receiving cell processor 2 (16) without changing the lower 2 bits of the mode HEC field. If it is assumed that the header value converted by the receiving cell processing unit 2 (16) is the same as the input header value, the VPI / VCI = 0/32 and HEC have 0x00 and 0x01, respectively, so that the receiving cell processing unit 3 (19) Is delivered). Always receiving cell processing unit 3 (19) is routed to the buffer 140 and the buffer 141 in the case of the cell delivered from the port 1, the cell delivered from the port 2 is routed to the buffer 138 and the buffer 141 The cell is transmitted to the transmitting cell processor 4 111. The reason why the receiving cell processor 3 19 determines that the cells transmitted from different ports are cells of different connections even when they have the same VPI / VCI value is the transmission. This is possible because the connection identifiers of the cells inputted through the ports 1 and 2 are different from each other by 0x00 and 0x01 by inserting the connection identifiers for each port in the cell processor 1 (12). 0x20 and 0x30 are inserted into the cell transmitted to the transmitting cell processor 4111 and 0x01 and 0x31 are inserted into the HEC field to be input to the receiving cell processor 4112. The receiving cell processor 4 112 transmits the cell transmitted on port 1. The cell transmitted on port 2 is distinguished by the least significant 2 bits of the connection identifier, and the port to be routed is distinguished by the 5th bit and the 4th bit. Convert to 0/33 and forward to port 3, 0x30 (11000 / b) to 0/34 to 0, and 0x01 (1 / b) to 0/35 to port 1, In case of 0x31 (110001 / b), it converts to 0/36 and forwards to port 4. In this case, when cell forwarding is requested to the same input VPI / VCI (3/32) from port 5 to port 3,4 The cell processing unit 3 (18) inserts 0xc0 (11000000 / b) into the connection identifier and distinguishes it from the internal communication cells (cells input through ports 1 and 2). In the processor 4111, one-to-multiple connection is possible by inserting different values for the cells copied from the fifth bit and the fourth bit.

In the above-described example, the change of each connection identifier for the cell transmitted to port 4 is described first. First, the cell inputted from port 1 is converted into 0x00 → 0x00 → 0x00 → 0x30, and the cell inputted from port 2 is 0x01 →. 0x01 → 0x01 → 0x31 is converted to port 1 cell, and port 5 is converted from 0xc1 → 0xf0 to have different connection identifiers from the cells input at ports 1 and 2 so that each port has the same VPI / VCI Even the cells are distinguished and forwarded to each port.

2 shows a cell format configuration diagram according to an embodiment of the present invention.

The HEC field is the fifth byte of the cell. The physical layer calculates the CRC from the first byte to the fourth byte of the header, and detects the error of the cell header and extracts the cell boundary when data is transmitted and received between different physical layers. Is the byte used to. Therefore, it is meaningless byte above the ATM layer, and in the present invention, it is a connection identifier for one-to-multiple connection.

3 is a block diagram of a connection recognizer according to an embodiment of the present invention.

The lower two bits (F1, F0) of the HEC field consisting of a total of 8 bits are used to distinguish between SBs, and bits F5 and F4 are used to distinguish between cells for communication between subscribers and networks in upstream. do. In the downstream flow, bits F7 and F6 are used to distinguish between cells from subscriber networks and cells from the network, using bits 4 and F4 to distinguish cells of the same header value copied for one-to-multiple connections. To be used.

The reason for inserting each SB port identifier in the lower 2 bits in the HEC field is first, by multiplexing the cells transmitted from the physical layer first, so that signal cells having the same header value among the cells transmitted from each physical layer (VPI / VCI) = 0/5) for each port, and second, to accept the same header value for each port, and to make the connection resource available for each port sufficiently. In the uplink HEC field, bits F5, The reason for inserting the delimiter between cell for communication between subscribers and network for F4 is that the loss of cells caused when the connection between subscribers is established first in the one-to-multiple connection and the network requests additional connection while requesting a connection value different from the already established connection value. This is to prevent.

The reason for inserting the delimiter between the subscriber-to-subscriber cell and the network-oriented cell in bits F7 and F6 in the downlink HEC field is to distinguish when the cell between the subscriber-to-subscriber cell and the network has the same connection value. The connection identifier of F4 assigns different identifiers to the cells copied by the receiving cell processor 3 (19) of the ATM layer function processor 3 (17), so that the receiving cell processor 4 (112) of the ATM layer function processor 4 (110). This is to distinguish the port value to be routed and to transfer it to the physical layer with different header values.

4 shows a flowchart according to an embodiment of the present invention.

First, when a cell is input at each physical layer port 1-4 (200), the transmitting cell processor 1 (12) inserts a connection identifier into the HEC field for each cell (201). When outputting to the receiving cell processing unit 1 (13) of the ATM layer function processor 1 (11), the receiving cell processing unit 1 (13) extracts only the header of the cell and compares it with the already set conversion header value (202). It is checked whether the cell is registered at (203). If the cell is not registered in the lookup table, the cell is recognized as a misinserted cell and discarded (204). If the cell is registered, it is checked whether it is an internal communication cell (205).

If the result of the investigation is not an internal communication cell, 0x3x is inserted into the HEC (206) and output to port 5, and if it is an internal communication cell, 0x0x is inserted into the HEC (208) and transmitted to the transmitting cell processor 3 (18).

In the next reception process, when the cell is input (300), it is determined whether the cell is an internal communication cell (301), and if it is not an internal communication cell, 0xc0 is inserted into the HEC (302), and if it is an internal communication cell, 0x0x is inserted into the HEC and multiplexed. After that, it transmits to the receiving cell processor 3 (19) (303).

Receiving cell processing unit 3 (19) determines whether the connection is one-to-one (304), if not a one-to-one connection, after routing the cell to all the buffers corresponding to the cell transmission to the transmitting cell processing unit 4 (111) (305), if the one-to-one connection The cell is routed to the buffer and transmitted to the transmitting cell processor 4111 (306), and the transmitting cell processor 4111 inserts a connection identifier to perform one-to-multiple (307), and outputs the corresponding port to the corresponding port ( 308).

The present invention operating as described above has a structure in which multiplexing is performed first in a small subscriber device such as a centralized network end device when the ATM layer supports one-to-one connection and one-to-one connection and broadcast connection in a B-ISDN environment. The HEC field, which is the fifth byte of the ATM cell header, can be used to perform one-to-multiple and broadcast connection functions without adding additional hardware.

Claims (1)

In the ATM cell processing method for a one-to-multiple connection, which is applied to a centralized broadband network termination device of a broadband integrated information communication network, when a cell is input, a connection identifier is inserted into the HEC field for each inputted cell. A first step (200 to 203) of extracting only the header of the cell and checking whether the cell is registered in the lookup table by comparing with the already-converted header value; A second step (204, 205) in which the cell is recognized as an erroneous insertion cell if the cell is not registered in the lookup table in the first step (200 to 203) and discarded if the cell is a registered cell; And a third step 206 of inserting 0x3x into the HEC if the cell is not an internal communication in the second step 204 and 205 and inserting 0x0x into the HEC if the cell is an internal communication and transmitting it to the transmitting cell processor 3 18 (206). And 209) and a fourth step (300, 301) of determining whether the cell is an internal communication cell when the cell is input; A fifth step (302 to 304) in which the fourth step (300, 301) inserts 0xc0 into the HEC if it is not a communication cell and inserts 0x0x into the HEC if it is an internal communication cell and multiplexes it by multiplexing; In the fifth step 302 to 304, if the cell copy is not one-to-one connection, the cell is routed and transmitted to all the buffers. If the one-to-one connection is performed, the cell is transmitted by routing the cell to the corresponding buffer. And a sixth step (305 to 308) of inserting a connection identifier and outputting the corresponding port to a corresponding port.