KR100231698B1 - Multicasting method and operation using - Google Patents

Abstract

The present invention relates to a structure of a multicasting system and a method of operating the same, wherein a single ATM protocol processor is used to compare and convert the cell heads consecutively N times within one cell time, and to check whether there is a copy of a cell using a connection establishment result of a connection table. The line card connected to the switch is used as the input / output card of the switch, which uses the method of directly copying the cell through the process of converting the head of the cell and having a different head value for each port. Proposes a method of multicasting a cell in a switch system having multiple physical layer ports connected to a single ATM protocol processor by using the same ATM layer protocol processor and modifying only the head converting device. OAM and signal cell processing to be handled by the ATM layer protocol handler By proposing a table operation method, multi-casting provided by each subscriber in the system by increasing the number of ports while using the same ATM protocol processor for the various line cards connected to the switch and having the same connection comparison conversion delay characteristics for each board Various services of the service can be provided, and through the proposed connection table control method, each port can separately transmit and receive signals and OAM cells by using the OAM and the signal processing window of one ATM protocol processor.

Description

Multicasting system structure and operation method {Multicasting method and operation using}

The present invention relates to a multicasting method in a system composed of a multicasting switch and a multiphysics layer connection card and a table operating method in a multiphysics layer connection card.

Conventionally, a single Asynchronous Transfer Mode (hereinafter referred to as ATM) switch may be connected to various speed access cards, while the system still has to provide the same service even when various access cards are connected.

For example, if a STM-1 speed card only supports multicasting in a connected system, multicasting functionality must be provided between connections, even if other types of line connection cards are connected to the system.

In addition, the line cards to be connected to the same switch must satisfy the minimum connection speed of the switch connection. A typical ATM switch uses STM-1 as the basic input / output speed.

Therefore, in case of low-speed subscriber connections, a protocol processor capable of processing STM-1 level data is used as an ATM layer for switch access, and only low-speed data is processed toward the subscriber.

According to the above, it is necessary to accommodate multiple physical layers through multiplexing and demultiplexing devices in one line card.

In general, in order to support PTMP (PTMP) service, an ATM multiplexer and a demultiplexer first use a method of copying and distributing cells to required ports and converting the heads of the cells at each port.

However, the use of such a device has many disadvantages of implementing hardware and complicated connection table management.

In order to solve the above disadvantages, the present invention enables one ATM layer of a line card to find N connection tables for one cell time and determine whether to copy a cell using a connection establishment result, and outputs a head value output from the connection table. Since the ATM layer protocol processor converts the head of the cell at the same time, we propose a dual multicasting method using a device for PTMP as a physically connected physical layer using one ATM layer protocol processor and a connection table. We propose a multicasting switch system that reduces the cost and reduces cell delay time.

The proposed device simultaneously performs cell copying and head conversion for multicasting in one cell time.

In addition, in order to share one connection table with multiple physical layers, the purpose is to provide a way to logically classify the table using input VPI / VCI values and port numbers and manage connection settings. .

1 is a structural diagram of a multi-casting switch having a two-layer structure to which the present invention is applied;

2 is an illustration of multicasting in accordance with the present invention.

<Description of the symbols for the main parts of the drawings>

10,110: low-speed physical layer receiving unit 11,111,121: input port

12,22,31,41,112,122,131,141: ATM layer

20,120: STM-1 physical layer receiving unit

30,130: low speed physical layer transmitter 32,132,142: output port

40,140: STM-1 physical layer transmitter 21,42,121: STM-1 physical layer

50,150: NxN switch

In order to achieve the above object, the present invention provides an MxM switch having a cell copy function, an STM-1 physical layer connection receiving unit and a transmitting unit connected to the MxM switch and providing a function of connecting data at an STM-1 speed; A low speed physical layer connection receiving unit having a plurality of physical layers connected to an ATM layer protocol processor, and a low speed physical layer transmitting unit receiving a cell output from the switch, converting a head, and copying and outputting a cell to multiple physical layers. Characterized in that.

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

1 is a structural diagram of a two-layered multicasting switch to which the present invention is applied, and STM-1 providing a function of connecting MxM switch 50, which is a switch having a cell copy function, and data of STM-1 speed. A physical layer connection receiving unit 20 and a transmission unit having an ATM head conversion function, a low-speed physical layer connection receiving unit 10 in which a plurality of physical layers are connected to one ATM layer protocol processor, and a cell output from the switch to convert the head. And a low speed physical layer transmitter 30 for copying and outputting a cell to multiple physical layers.

1 shows the proposed dual-casting multicasting system structure. The centrally located MxM switch 50 is a switch having a cell copy function.

In order for such a switch system to provide PTMP service, each input line card and output line card must be able to switch heads separately.

For example, a Virtual Path Identifier / Virtual Channel Identifier (hereinafter referred to as VPI / VCI) of a cell entered through a port of a switch is input with numbers 0/51 and entered into two cells of the switch. Assume that it is copied and output to any output port.

In this state, the cells output to the output ports have different connections, which is a PTMP service. To accommodate this, the ATM head must be independently converted at each output port of the switch.

In FIG. 1, the system shows two types of line cards. The STM-1 physical layer connection receiving unit 20 and the transmitting unit 40 provide a function of connecting data of the STM-1 rate. Each transmitter has an ATM head conversion function.

In the slow physical layer connection receiving unit 10 connected to the ATM switch, a plurality of physical layers are connected to one ATM layer protocol processor.

N physical layer ports share a data bus and only control signals are separated and connected to an ATM layer protocol processor.

ATM layer protocol handlers and physical layer protocol handlers use existing ones and additionally access devices to connect multiple physical layers to one ATM protocol processor.

The added device generates a port identifier that distinguishes the input port of the cell, and when the ATM protocol processor outputs only the head to convert the cell head, the device combines the port separator to find the connection table.

These additional devices allow you to physically identify and manage ports using a single connection table.

In addition, it performs a function of separating maintenance operation (Operation, Administration and Maintemance, hereinafter referred to as OAM) and signal cells from the input cells, and distinguishing which cells are inputted from which ports and transmitting them to the OAM and the signal processing processor.

The low speed physical layer transmitter 30 is a device that receives a cell output from a switch, converts a head, and copies and outputs a cell to multiple physical layers.

The transmitter 30 connects and uses a plurality of physical layer protocol processors to one ATM layer protocol processor to prevent bandwidth waste.

In general, a method of multicasting a cell is performed by first copying the required number of cells, and then converting each head of each cell.

The proposed device performs connection comparison transformation N times consecutively for one cell time by using input head data and port separator for connection comparison conversion to find out whether the connection is established for each port, and to check whether there is a cell output to each physical layer. It then waits for N comparison conversions while storing the converted heads for each port in hardware.

After performing N connection comparison conversions, the head comparison conversion device generates a control signal to output a cell from the ATM protocol processor.

When the ATM protocol processor outputs a cell, the cells are multicasted by using the heads stored in hardware to simultaneously convert the heads and copy the cells to the physical layer.

The proposed multicasting method is not a method of first copying and storing a cell and then converting the head, but instead of converting the head for N ports for one cell time and simultaneously converting the cell head output from the ATM protocol processor to the physical layer. The output reduces head comparison, cell copying, and cell copying for multicasting in less than one cell time, thereby reducing hardware delay, cell copying, and concatenation.

Therefore, the proposed multicasting architecture copies cells in one step from the switch, and performs a connection comparison conversion in the ATM protocol processor of the subscriber card. It features a function that allows output.

In the above process, the low-speed subscriber interface reduces the amount of hardware by using a structure that uses one ATM layer protocol processor and one connection table, and supports PTMP service while reducing cell delay.

To illustrate an example for multicasting in the system of FIG. 1, a connection configuration is shown in FIG. 2.

FIG. 2 is an exemplary diagram of multicasting according to the present invention. It is assumed that one input is established between the input port 111 and the output ports 132 and 142 of the low-speed physical layer connection unit 110. It was.

The input cell is copied to two cells in a switch, and a two-stage cell copy structure is used in which two cells are copied again at the slow physical layer connection unit 110.

In this case, when the copied cell is outputted, it should be able to have different head values independently.

In order to perform such a function, the transmitter of each line card has a head conversion function.

The low-speed physical layer connection unit 110 and 130 used in the present invention copy input cells using a process of performing a link comparison transformation without copying cells separately in the head transformation process of the ATM layer, and at the same time, different head values for each port. Has the function to convert

In order to compare and convert connections between ATM and physical layers and to copy cells, one connection table is logically divided and shared by using VPI / VCI values of input cells and additional port separators.

First, the VPI / VCI value of the cell inputted to the low-speed physical layer connection unit 110 is found and stored, and the output connection values are extracted by comparing the connection table N times consecutively by combining the port number from 0 to N-1 sequentially. After the extraction of the Nth output head, the cell head is changed at each port at the same time, and the cells are selectively copied to output the cells to N physical layers.

In the multicasting method of this structure, the following method is used to maintain connection for each port.

In general, the input VPI / VCI and output VPI / VCI are recorded in the connection table for head conversion, and the output VPI / VCI is found by the input VPI / VCI.

In addition to this structure, additional port numbers are recorded in the connection table to find the output VPI / VCI by the input VPI / VCI and the port separator. For example, the GFC area of the cell is used.

Even if each port uses the same input VPI / VCI, the connection is divided by port number. During N connection comparison conversion, a matching signal is generated for any ports that match the input VPI / VCI. Cells can only be output to configured ports.

In addition, in order to transmit a signal cell or OAM cell in the physical layer, the head and port number of each cell are recorded and then a transfer command is issued to transmit a cell to only a desired port while performing head conversion.

The multiplexer transfers the ATM layer by recording the input port numbers in the input cells, and the signal cell or the OAM cell terminated in the receiver ATM layer is an unused portion of the head area of the cell, for example, GFC or HEC ( Record the port number in the Head Error Correction area and pass it to the central processing unit (CPU), or distinguish each connection and port by using the VPI / VCI area separately in the system for the cell input to each port. .

This architecture provides a multicasting switch architecture with an increased number of ports throughout the system with the help of software while simplifying the architecture of the hardware.

As described above, the rescue apparatus proposed by the present invention is not a conventional method of first using a method of comparing the heads of cells input to a line card, copying the cells as necessary, and converting the heads of the copied cells. Using a demultiplexer, which compares the heads of cells input to the ATM protocol handler, reduces the amount of traffic inside the switch and reduces the amount of traffic inside the switch when multiple low-speed subscribers belonging to a board become leafs of the PTMP service. The delays for the head conversion and copying are made to have the same delay as other line cards.

Therefore, various line cards connected to the switch use the same ATM protocol handler and each board has the same connection comparison conversion delay characteristics, increasing the number of ports so that each subscriber can receive various services such as multicasting service provided by the system. In addition, through the proposed connection table control method, each port can transmit and receive signals and OAM cells by using the OAM and the signal processing window of one ATM protocol processor.

Claims (5)

Multicasting using head conversion method that can connect multiple physical layer protocol processors from one ATM layer protocol processor to assign different head value to each port and manage connection table in the device to distinguish each port and transmit / receive OAM And a table operation for processing signal cells, An MxM switch having the cell copy function; An STM-1 physical layer connection receiving unit and a transmitting unit connected to the MxM switch and providing a function of accessing data at an STM-1 speed; A low speed physical layer connection receiving unit in which a plurality of physical layers are connected to one ATM layer protocol processor; And a low speed physical layer transmitter configured to receive a cell output from the switch, convert a head, and copy and output a cell to multiple physical layers. The method of claim 1, wherein the slow physical layer transmitter A multicasting system architecture, in which a plurality of physical layer protocol processors are connected to and used by one ATM layer protocol processor to prevent bandwidth waste. An MxM switch having a cell copy function, an STM-1 physical layer access receiver and a transmitter connected to the MxM switch to provide an STM-1 speed data access function, and a plurality of physical layers are connected to an ATM layer protocol processor A low speed physical layer connection receiving unit comprising: a low speed physical layer transmission unit configured to receive a cell output from the switch, convert a head, and copy and output a cell to a plurality of physical layers; A first step of using a port identifier to logically distinguish and use one table in the multicasting system; And a second step of table operation for transmitting and receiving signaling and maintenance operation management (OAM) cells using the one ATM layer protocol processor. The method of claim 3, wherein the first process is Record the input virtual path identifier / virtual channel identifier (VPI / VCI) and output VPI / VCI in the connection table for head conversion, And additionally recording additional port numbers in the connection table to find the output VPI / VCI by the input VPI / VCI and the port separator by the input VPI / VCI and the port separator. The method of claim 3, wherein the second process is Record the head and port number of each cell to transmit signal cells or OAM cells in the physical layer, After recording the head and port number of each cell, the transfer command is issued to convert the head to the desired port. It transfers ATM layer by recording the input port number in cells input from multiplexer. The signal cell or OAM cell terminated at the receiver ATM layer records the port number in the unused part of the cell area and forwards it to the CPU. A method for operating a multicasting system, characterized by dividing each connection and port by dividing a VPI / VCI region within a system for cells inputted to the respective ports.

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