KR20010054699A - Method and apparatus for searching channel connection information of an atm cell - Google Patents

Abstract

PURPOSE: A method and apparatus for searching channel connection information of an ATM cell are provided to search a VC channel table by using only a VCI value of a received ATM cell and minimize time required for identifying channel connection information according to reduction of the memory occupancy number by obtaining areas of a channel information recording table as many as maximum channels to be used and recording channel connection information in an inherent area of each channel. CONSTITUTION: An ATM system ANDs a virtual pass mask value assigned to an inherent link number of a physical layer used for transmission of an ATM cell and a virtual pass identifier to generate an index of a virtual pass table previously stored in an external memory, and reads a VP(Virtual Path) mask value from an internal register(106) corresponding to the link number. Then, the ATM system ANDs a VPI(Virtual Path Identifier) value(102) of the ATM cell and the VP mask value read from the internal register(106) to generate a VP table index value. The ATM system adds the VP table index value and a VP base address value provided from the internal register(106) to generate a VP table address value. Subsequently, the ATM system reads out a VC(Virtual Channel) mask value stored in the VP table address of the VP table(112) having a plurality of VC mask values, and ANDs the read VC mask value and the VCI(Virtual Channel Identifier) value(104) of the ATM cell to generate a VC index value.

Description

Method and apparatus for retrieving channel connection information of AT cell {METHOD AND APPARATUS FOR SEARCHING CHANNEL CONNECTION INFORMATION OF AN ATM CELL}

The present invention relates to retrieval of channel connection information in an asynchronous transmission mode system. More specifically, the time required for checking predetermined channel connection information using a virtual path identifier and a virtual channel identifier can be minimized. The present invention relates to a method for retrieving channel connection information in an asynchronous transmission mode system.

1 is a view showing the structure of a typical AT cell, Figure 2 is a view for explaining a method for retrieving the channel connection information in a conventional asynchronous transmission mode system.

Referring to FIG. 2, the conventional asynchronous transmission mode system visits the internal register 18 shown in FIG. 2 using the link number 16 of the physical layer when the AT cell is received. The asynchronous transfer mode system generates a VPI index value by combining the VPI mask value 20 read from the internal register 18 with the VPI 12 value, and then generates a VPI table base value 22. ) Is used to generate an address of the VP table 24.

Next, the asynchronous transmission mode system reads the BC mask value 26 using the address of the VP table 24 and combines it with the VCI 14 to generate the VCC. The index value is combined with the BC list base value 28 to generate a BC list address.

The asynchronous transfer mode system reads the index of the BC table actually established in the BC list table 30, that is, the Connection ID (CI) using the BC list address, and stores the IC register as an internal register. In combination with the BC table base 32 from (18), the channel connection is confirmed in the BC table 34.

However, such a method accesses the actual BC table 34 using a value read by accessing the BC list table 30, which is an external memory, in order to find a table where the last channel connection information exists. Access twice.

In addition, the structure of the BC list table 30 requires a large amount of space to handle 65536 channels that can be represented by a 16-bit BC eye value, resulting in a waste of memory.

The present invention provides a method and apparatus for retrieving channel connection information in an asynchronous transmission mode system capable of minimizing the time required to check predetermined channel connection information using a virtual path identifier and a virtual channel identifier. Its purpose is to.

1 is a view showing the structure of a typical AT cell;

2 is a view for explaining a method for retrieving channel connection information in a conventional asynchronous transmission mode system; And

3 and 4 are diagrams for explaining a method for retrieving channel connection information in an asynchronous transmission mode system according to a preferred embodiment of the present invention.

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

100: link number 102: VPI

104: VCI 106: Internal register

108: VP mask 110: VP table base

112: VP table 114: VC mask

116: VC table base 118: VC table

A method for retrieving channel connection information in an asynchronous transmission mode system according to the present invention for achieving the above object, using the virtual path identifier and virtual channel identifier of the ATM cell for asynchronous transmission mode communication A method of retrieving channel connection information of a virtual path table, the virtual path table allocated to a unique link number of a physical layer used for transmission of an AMT cell and a virtual path table pre-stored in an external memory by logically multiplying the virtual path identifier Generating an index of C, reading a virtual channel mask value stored in a virtual path table address obtained by adding a predetermined base address of the index, and logically multiplying the virtual channel mask value by the virtual channel identifier. Create an index of the virtual channel table previously stored in external memory. And reading the channel connection information of the AT cell stored in the virtual channel table address obtained by adding an index of the virtual channel table and a preset base address.

Apparatus for retrieving channel connection information in the asynchronous transmission mode system according to the present invention for achieving the above object, in the device for searching and processing the virtual channel information of the AT cell having a virtual path identifier and a virtual channel identifier A virtual path table storage means that is a set of virtual channel mask values, a virtual channel table storage means that is a set of channel connection information, a virtual path mask value assigned for each unique link number of a physical layer used for transmission of the ATM cell, and And a register storing a base address of the virtual path table, a base address of the virtual channel table, and a value obtained by logically multiplying the virtual path mask value and the virtual path identifier when the AT cell is received. To specify each register of the virtual path table by adding Obtaining a dress, reading a virtual channel mask value stored at the corresponding address, and adding each of the virtual channel table base addresses to a logical product of the virtual channel mask value and the virtual channel identifier to designate each register of the virtual channel table. Control means for obtaining an address and reading out channel connection information stored at the address.

According to this method, the asynchronous transmission mode system secures an area of the channel information recording table for the maximum number of channels to be used, and records the channel connection information in a unique area of each channel when recording the channel connection information.

Therefore, the B channel table can be searched using only the BC eye value of the received AMT cell, and the memory occupancy can be reduced, thereby minimizing the time required to check the channel connection information. .

Hereinafter, a method for retrieving channel connection information in an asynchronous transmission mode system according to an embodiment of the present invention will be described in more detail with reference to FIGS. 3 and 4.

3 is a view for explaining a method for retrieving channel connection information in an asynchronous transmission mode system according to a preferred embodiment of the present invention, Figure 4 is a channel connection information in an asynchronous transmission mode system according to a preferred embodiment of the present invention Figure is a diagram showing a data structure for searching.

Referring to FIG. 3, the asynchronous transfer mode system includes an internal register 106 having a VP table base address value, a BC list base address value, a BC table base address value, and a plurality of VP mask values, and a plurality of BC mask values. And a VP table 112 having a channel connection information.

If, in the agreement with the other party to communicate with, if the channel with VCI value 2 and channel 137 is set first, the host writes to the BC channel table starting with base address 10 and then writes twice with address 11. Instead of recording the BC eye channel information, the channel information of the BC eye is 2 is recorded in the area of address 12 and the channel information of the BC eye 137 is recorded in the area of the address 23 using the determined BC mask value. The remaining areas are areas to be set during communication later. Therefore, the maximum table area to be used is fixed and the channel information generated is recorded in order, or the corresponding unique area is found and recorded, but the size of the remaining empty space is the same.

In this case, the plurality of BC mask values in the VP table 112 have different values, and the BC mask values are used to distinguish the number of available channels and the number of available channels determined by negotiation between ATM networks. It is determined depending on the type of the BC eye configuration bit actually used.

FIG. 4 is a diagram illustrating a method for retrieving channel connection information according to an embodiment of the present invention. The number of channels used is 16 by manganese negotiation. In this case, the four bits of the 3rd, 7th, and 3rd bits are set to represent the V-eye value.

Therefore, the host secures and configures a channel table having 16 records. As the 0, 1, 3, and 7th bits of the 16 bits of VC are used, the BC mask value is represented by the value of decimal 139. .

4 illustrates a case where the BC table base address is set to decimal 10 as an embodiment of the present invention. Hereinafter, a case where each cell having a value of VI 137 and 2 is received will be described as an example.

First, the asynchronous transmission mode system generates an index of a virtual path table previously stored in an external memory by logically multiplying a virtual path mask value assigned to a unique link number of a physical layer used for transmission of an AT cell by the virtual path identifier. The VP mask value 108 is read out from the internal register 106 corresponding to this link number.

Next, the asynchronous transmission mode system generates a VP table index value by performing an AND operation on the VP 102 of the AT cell and the VP mask value read from the internal register 106.

The asynchronous transfer mode system adds the BP table index value to a BP base address value provided from the internal register 106 to generate a BP table address value.

Subsequently, the asynchronous transmission mode system reads a BC mask value stored in the VP table address of the VP table 112 having a plurality of BC mask values, and stores the read BC mask values in the VMS cell. The VCI value is generated by performing logical AND on the CSI value 104.

Here, as illustrated in FIG. 4, the VCI values 104 are assumed to be "137" and "2".

That is, when the BC eye value 104 is "137", only 0, 1, 3, and 7th bits of the 16-bit data bits representing the BC eye are used for channel connection information retrieval and are shown in FIG. As can be seen that the values are sequentially 1, 0, 1, 1.

In addition, the BC mask used to process the AMT cell is also a decimal 139 in which the values of 0, 1, 3, and 7 bits of the 16 bits are represented by '1'. "1101", which is the result of logically multiplying the BC eye value of '137', is obtained as the BC index.

Next, the asynchronous transfer mode system determines the BC table base address value " 1010 " provided from the BC index value " 13 " 1101 and the internal register 106 when the BC eye value 104 is " 137 ". (In the case of a decimal number, "10" is added) to generate a BC table address value "23h".

The host of the asynchronous transmission mode system stores the channel connection information of the AT cell having the received BC eye 137 based on the generated BC table address value "23h" at the time of initial setting. Channel connection information stored at a corresponding address can be obtained within 118.

If the BC eye value 104 is "2", the BC eye value 104 is a 0, 1, 3, 7 bit value of 16 bit BC eye sequentially 0, 1, 0, 0 It is possible to obtain an index of "0010" through the logical product of the BC mask represented by the decimal number 139.

In addition, when the BC index value "0010" and the BC table base address value "1010" are added, it can be seen that the BC table address value corresponding to the BC eye value 104 "2" is "12h". have.

Therefore, the asynchronous transfer mode system reads out the channel connection information of the received AT cell from the storage of the address "2h" in the BC table 118 based on the generated BC table address value "12h". do.

According to the method for retrieving channel connection information in the asynchronous transmission mode system as described above, the asynchronous transmission mode system secures an area of the channel information recording table as many as the number of channels to be used and records the channel connection information. In this case, the channel connection information is recorded in a unique area of each channel.

Therefore, the B channel table can be searched using only the BC eye value of the received AMT cell, and the memory occupancy can be reduced, thereby minimizing the time required to check the channel connection information. .

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated.

Claims (2)

A method for retrieving channel connection information of an AT cell using a virtual path identifier and a virtual channel identifier of an AT cell for asynchronous transmission mode communication, Generating an index of a virtual path table previously stored in an external memory by logically multiplying a virtual path mask value assigned to a unique link number of a physical layer used for transmission of the AT cell by the virtual path identifier; Reading a virtual channel mask value stored in a virtual path table address obtained by adding a predetermined base address of the index; Generating an index of a virtual channel table previously stored in the external memory by performing a logical AND of the virtual channel mask value and the virtual channel identifier; And And reading the channel connection information of the AT cell stored in the virtual channel table address obtained by adding the index of the virtual channel table and a predetermined base address. . An apparatus for retrieving and processing virtual channel information of an AT cell having a virtual path identifier and a virtual channel identifier, Virtual path table storage means which is a set of virtual channel mask values; Virtual channel table storage means that is a collection of channel connection information; A register storing a virtual path mask value assigned to each unique link number of the physical layer used for transmission of the AMT cell, a base address of the virtual path table, and a base address of the virtual channel table; And Upon receipt of the AT cell, the virtual path table base address is added to a value obtained by logically multiplying the virtual path mask value with the virtual path identifier to obtain an address for designating each register of the virtual path table, and storing the virtual address stored in the corresponding address. Read a channel mask value, add the virtual channel table base address to the logical product of the virtual channel mask value and the virtual channel identifier to obtain an address designating each register of the virtual channel table, and store the channel stored at the address. Apparatus for retrieving channel connection information of an AT cell, characterized in that it comprises a control means for reading the connection information.