KR100356756B1 - Apparatus for searching a connection table of atm switch - Google Patents

Abstract

The present invention relates to an asynchronous transmission mode switch, and the present invention stores connection information and an output identification number, and the connection information corresponding to a virtual channel identification number (VCI) and a virtual path identification number (VPI) of an input ATM cell. And an inner cell forming unit configured to add an output side identification number to the input ATM cell to configure and output an inner cell; A switch block receiving the inner cell from the inner cell forming unit and providing the inner cell to an output port corresponding to the connection information in the inner cell; An inner cell reader for storing operation management information of the inner cell with an address of an output side identification number of the inner cell provided from the switch block; Providing the output side identification number and connection information corresponding to the VPI and VCI of the ATM cell to the internal cell forming unit, and providing the output side identification number to the internal cell reading unit to obtain the required VPI and VCI operation management information A call processing block is provided.

Therefore, the present invention has the effect that the information on the cell on the output side of the asynchronous transmission mode switch can be easily detected using the output side identification number.

Description

APAPATUS FOR SEARCHING A CONNECTION TABLE OF ATM SWITCH}

The present invention relates to an asynchronous transfer mode switch, and more particularly, to an apparatus capable of easily searching for a connection corresponding to a virtual path identifier (VPI) and a virtual channel identifier (VCI) at a switch output side. will be.

Broadband ISDN (Broadband-ISDN) needs to deal with a wide range of information from low speed to ultra high speed, and ATM switching is considered. The ATM switching system is based on a packet called a fixed length cell having 53 bytes. A 53-byte cell consists of a 5-byte header and 48-byte information containing control information such as destination label information and routing information. That is, in the ATM switching method, the virtual channel identifier (VCI) and the virtual pass identifier (VPI), which are routing information, are used to determine which virtual path and which virtual channel to select and communicate with the other party. do.

Since the VCI and VPI become routing information in the ATM switch, each time, the VCI and VPI are converted into other VCIs and VPIs set in advance through separate header converters.

On the other hand, since the ATM switch must be operated in hardware to operate at high speed, conventionally, as shown in FIG. 1, additional connection information is added to the ATM cell (these cells are referred to as internal cells) to control switching of the ATM switch. have. By the connection information, the ATM switch is switched at high speed in hardware.

A method of adding connection information corresponding to VPI and VCI in an ATM cell is to configure a memory having an address corresponding to the number of VPI and VCI. Addresses corresponding to the available VPIs and VCIs are formed in the memory, and the connection information is stored in the addresses. In this configuration, when the ATM cell is applied, only the header information of the VPI and VCI in the ATM cell is read, and the connection information stored in the address of the memory (corresponding to the VPI and VCI) corresponding to the header information is added to the ATM cell, thereby causing the internal cell. To form.

However, such a method requires a large amount of memory, and a problem arises in that the capacity of the memory is not effectively used.

In other words, when the memory is configured to have an address corresponding to both the available VPI and VCI in the ATM switch, the memory should be configured in a large capacity. In particular, the general ATM switch does not use the VPI and VCI mode but selects a small number of them. Since only VPI and VCI are used, the capacity of the memory is wasted when using a large amount of memory.

In order to solve this problem, a conventional content addressable memory (CAM) is used. The CAM refers to a memory that determines whether there is information corresponding to the address with respect to the input address information, and reads and provides the information when the corresponding information exists. Traditionally, this capability of the CAM was used to simply form internal cells. Specifically, the address of the CAM is formed in correspondence with the VPI and the VCI, and the address in the table configured separately is stored in this address. That is, the connection information corresponding to the VPI and VCI is stored in a separate table, and the address of this table is stored in the CAM. Here, when the VPI and the VCI are input, the CAM determines whether the VPI and the VCI are stored and provides address information of a table stored at an address corresponding to the stored VPI and the VCI. That is, since the CAM provides an address of a table in which connection information corresponding to VPI and VCI in the ATM cell is stored, an internal cell can be formed using this information.

On the other hand, such a CAM should be configured at the input and output of the ATM switch, respectively. As described above, the CAM and the table for adding connection information for controlling the switching of the ATM switch should be formed at the input terminal of the ATM switch, and the CAM and the table should be configured at the output terminal of the ATM switch as follows. In order to manage ATM switches, it is necessary to observe whether they are used for each VPI and VCI (necessary for billing usage fees), and to observe whether there is a failure in a channel. In response to this need, a table was formed at the output of the ATM switch, and information such as whether VPI and VCI were used and failure was stored in the table. The information was read from the table when needed for operation. Even in such a configuration, since information must be read for each VPI and VCI, a CAM and a table are also configured in the output terminal of the ATM switch to read information necessary for each VPI and VCI.

However, this conventional method has a problem that the manufacturing cost is high in the hardware configuration because the CAM must be formed at the input terminal and the output terminal of the ATM switch, respectively.

The present invention has been made to solve this problem, and an object of the present invention is to provide an apparatus capable of reading necessary information for each VPI and VCI without forming a CAM at the output terminal of the ATM switch.

In order to achieve the above object, the present invention relates to an asynchronous transmission mode switch in which connection information and an output identification number are stored, and correspond to a virtual channel identification number (VCI) and a virtual path identification number (VPI) of an input ATM cell. An inner cell forming unit configured to add connection information and an output side identification number to an input ATM cell and configure and output the inner cell; A switch block receiving an inner cell from an inner cell forming unit and providing an inner cell to an output port corresponding to connection information in the inner cell; An internal cell reading unit for storing operation management information of the internal cell using the output side identification number of the internal cell provided from the switch block as an address; Call processing block that provides output side identification number and connection information corresponding to VPI and VCI of ATM cell to internal cell forming unit and output side identification number to internal cell reader to equalize required VPI and VCI operation management information It is provided.

1 is a diagram illustrating a format of a cell used in a connection table search apparatus in an asynchronous transmission mode switch according to the present invention;

2 is a conceptual diagram of a switch system used in a connection table search apparatus in an asynchronous transmission mode switch according to the present invention;

3 is a schematic block diagram of an internal cell forming unit configured in a connection table searching apparatus in an asynchronous transmission mode switch according to the present invention;

4 is a schematic block diagram of an internal cell information reading unit configured in a connection table searching apparatus in an asynchronous transmission mode switch according to the present invention;

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

10, 11: subscriber / relay line block 20: switch block

30 call processing block 100 internal cell forming portion

110, 210: logic controller 120: CAM

130, 230: table

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

2 is a schematic block diagram of an ATM switch. As shown, each subscriber or other ATM switch of the ATM switch is connected to the ATM switch block 20 via subscriber / relay line blocks 10,11. In this configuration, the call processing block 30 provides the subscriber / relay line blocks 10 and 11 with connection information corresponding to the VPI and VCI to set up a call between subscribers. The connection information is added to the ATM cell in the subscriber / relay line blocks 10 and 11 as will be described later, and the switch block 20 is switched according to the connection information to those skilled in the art. will be.

The subscriber / relay line block 10, 11 adds the connection information from the call processing block 30 to the ATM cell to form an inner cell, and provides this inner cell to the switch block 20. The switch block 20 is switched according to the connection information to provide an internal cell to the output port according to the connection information, and the subscriber / relay line blocks 10 and 11 remove the connection information from this internal cell and then remove the subscriber / or not shown. Provide ATM cells to other ATM switches.

3 illustrates a configuration of the internal cell forming unit 100 formed in the subscriber / relay line blocks 10 and 11 in the above-described configuration.

As shown, the input ATM cell is provided to the inner cell forming unit 100, and the inner cell forming unit 100 includes a logic controller 110, a CAM 120, and a table 130. In the table 130, connection information and an output side identification number are stored. That is, the logic controller 110 receives the connection information and the output side identification number information corresponding to the VPI and the VCI from the call processing block 30, which is the upper block, and stores the information in the table 130. The connection information is information for controlling the switching of the switch block 20 as described above, and the output side identification number is the internal cell information reading unit 200 of FIG. 4 formed in the subscriber / relay line blocks 10 and 11 described later. Is to address my table 230. Since the internal cell information reading unit 200 has been described in detail later, description thereof will be omitted.

The logic controller 110 stores the address in the table 130 in which the connection information and the output side identification number are stored in the CAM 120 as the input side identification number, and the address of the CAM 120 is from the call processing block 30. Corresponds to VPI and VCI. That is, the logic controller 110 receives the VPI and the VCI, and the connection information and the output side identification number corresponding to the VPI and the VCI, respectively, from the call processing block 30, and the provided VPI and the VCI are the addresses of the CAM 120. The connection information and the output side identification number are stored in the table 130, and the address of the table 10 in which the connection information and the output side identification number corresponding to the VCI and VPI are stored in the CAM 120 is used as the input side identification number. To save. Therefore, the connection information and the output identification number corresponding to the VPI and the VCI can be easily detected via the CAM 120 and the table 130.

The logic control unit 110 of the internal cell forming unit 100 in the subscriber / relay line block 10, 11 reads the VPI and VCI from the ATM cell, and inputs the identification number corresponding to the read VPI and VCI to the CAM 120. The logic controller 110 reads the connection information and the output side identification number stored in the address in the table 130 corresponding to the read input side identification number, and inputs the read connection information and the output side identification number. In addition to forming an inner cell.

The inner cell formed through the above-described process is provided to the switch block 20, the switch block 20 is switched according to the connection information in the inner cell to provide the inner cell to the corresponding output port.

3 shows the configuration of an internal cell information reader 200 in subscriber / relay line blocks 10 and 11.

The internal cell information reader 200 includes a logic controller 210 and a table 230 as shown. In the table 230, operation information such as information on ATM cells for each VPI and VCI, that is, whether a channel is used or a failure is stored, but the stored address corresponds to an output side identification number included in an internal cell. That is, the logic controller 210 extracts the output identification number from the user cell and stores the operation information of the ATM cell at an address of the table 230 corresponding to the extracted output identification number.

Information in the table 230 is information required for the call processing block 30, which is a higher block, to manage the entire ATM switch. Therefore, the call processing block 30 must read the information in the table 230, and for this purpose, the output side identification number in the table 230 must be known. Here, the call processing block 30 provided the connection information and the output side identification number information corresponding to the VPI and the VCI to the internal cell forming unit 100 as described above. Therefore, since the call processing block 30 grasps the output side identification number corresponding to the VPI and VCI, it is possible to easily read the information of the required VPI and VCI. Here, the call processing block 30 provides the logic control unit 210 with the output side identification number of the table 230 as needed, and the logic control unit 210 uses the provided output side identification number to provide predetermined information in the table 230. Is read and provided to the call processing block 30.

As can be seen from the above description, it can be seen that in the present invention, only one CAM 120 is used in one ATM switch. That is, only the inner cell forming unit 100 needs the CAM 120, and the inner cell information reading unit 200 does not need the CAM. This is implemented because the call processing block 30 provides connection information for each VPI and VCI of the ATM cell to the internal cell forming unit 100 at the same time, and at the same time provides a separate output side identification number in advance.

As can be seen from the above description, the internal cell in the present invention has a burden that the output side identification number is added to the ATM cell in addition to the connection information, but this is not a large burden compared to the hardware burden of using one more CAM. Will be readily apparent to those of ordinary skill in the art.

In addition, in the present invention, the call processing block has a burden to designate and manage the output identification number, but this is also not a large burden compared to the hardware burden of using one more CAM.

As described above, the present invention has the effect that the CAM can be used only on the input side instead of configuring the CAM on each of the input side and the output side in the ATM switch, thereby simplifying the hardware configuration.

Claims (3)

delete delete In the asynchronous transfer mode switch, The connection information and the output side identification number are stored, and the connection information and output side identification number corresponding to the virtual channel identification number (VCI) and the virtual path identification number (VPI) of the input ATM cell are added to the input ATM cell to the internal cell. An internal cell forming unit configured to output; A switch block receiving the inner cell from the inner cell forming unit and providing the inner cell to an output port corresponding to the connection information in the inner cell; An inner cell reader for storing operation management information of the inner cell with an address of an output side identification number of the inner cell provided from the switch block; Providing the output side identification number and connection information corresponding to the VPI and VCI of the ATM cell to the internal cell forming unit, and providing the output side identification number to the internal cell reading unit to obtain the required VPI and VCI operation management information Have a call processing block, The internal cell forming unit includes: a first table for storing the output side identification number and the connection information according to an input side identification number; A CAM for storing the input identification number for each VCI and VPI; Store the output side identification number and the connection information in a first table according to information from the call processing block, store the input side identification number of the first table in the CAM at an address corresponding to the VCI and VPI, and input A first logic controller configured to read the output side identification number and the connection information corresponding to the VCI and the VPI in the ATM cell by using the CAM and the first table and add the read-out identification number to the ATM cell to form the internal cell; The internal cell information reading unit includes: a second table storing an operating state of an ATM cell for each of the VCI and VPI using the output side identification number as an address; And a second logic controller for providing operation management information corresponding to the output side identification number from the call processing block to the call processing block.