JP2002152225A - Multiple address cell copy system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system that can realize copying of multiple address ATM cells having a simple configuration, without the need for provision of an exclusive buffer for copying the multiple address cells. SOLUTION: The multiple address cell copy system consists of an input channel compatible section 10, having an input buffer section 11, a switching (SW) section 20 having a switch copy function 21, and output channel compatible sections 30. Each of the output channel compatible sections 30 has a level recognition function 31, a copying function 32, a header conversion function 33, an output buffer section 34, and a channel output section 35. The copy function 32 has a copy control 321 and a priority ranking control function 322. The copy control 321 has a queue control function 323, a queue buffer 324 and a one-cell buffer 325. Furthermore, the header conversion function 33 has an HT conversion and copy control function 331 and an HT memory function 332.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcast cell copy system, and more particularly, to an ATM (Asynchronous Transfer Mode).
fer Mode) relates to a method of copying broadcast cells in a switch.

[0002]

2. Description of the Related Art Conventional examples of this type of broadcast cell copy system and related technologies include, for example, a "broadcast communication system" in Japanese Patent Application Laid-Open No. 8-37525 and a "cell in an ATM network" in Japanese Patent Application Laid-Open No. 5-136814. Copying apparatus "
No. 283818, “Cell data exchange method and exchange device” and the like. As disclosed in the above-mentioned first publication, it has a dedicated buffer for copy processing. Regarding the priorities, the results of comparing the priorities of the broadcast copy processing buffer and the arriving cell each time are as follows:
A method of switching a route by a selector circuit or the like is adopted.

As shown in the block diagram of FIG. 6, this conventional example comprises a route (or header) converter 1, an address table (broadcast sharing) 2, a copy processing circuit 3, and a selector 4. The input signal is input to one input terminal of the selector 4, and the output signal of the copy processing circuit 3 is input to the other input terminal. The output signal of the selector 4 is input to the route converter 1. This route conversion unit 1
It is bidirectionally connected to the address table 2. Route conversion unit 1
Outputs an output signal and is input to the copy processing circuit 3.

The operation of the broadcast communication system shown in FIG. 6 will be described. The cells input to the selector 4 are replaced with information identifiers (VPI / VCI values, etc.) by the route converter 1 and the address table 2. At this time, if the input cell is a broadcast copy target cell, the input cell is fed back to the selector 4 via the copy processing circuit 3. The priority of the fed back copy cell is compared with that of the input cell by the selector 4, and a process is performed so as to select a cell having a higher priority. As a result, priority control is performed between the input cell and the copy cell, thereby preventing a cell with a higher priority from waiting.

[0005] As for header conversion, a system for directly converting cells by providing a table for cell header conversion of a broadcast copy in the same memory is adopted. FIG. 7 shows a conventional example of a header conversion table. As can be understood from FIG. 7, a conventional method is to directly map route information from a route address. Based on the concept of group address, the header conversion table has copy number information in addition to route information. Further, at the time of broadcast copying, the route information is searched by adding an offset to the route address.

[0006]

However, the prior art as described above has several problems as follows. First
And a buffer dedicated to broadcast copying. The reason is that the circuit size is large and the cost is high due to having the cells dedicated to the broadcast copy. Second, the route is switched between the broadcast copy cell and the normal cell by the selector. The reason is that the processing of the broadcast copy cell and the processing of the normal cell are different, so that the control becomes complicated and the circuit scale becomes large. Third, the header conversion memory (table) is used in common with the broadcast. The reason is that one cell occupies only the destination of the broadcast copy,
If there are a large number of cells that are not broadcast copy targets, the memory cannot be used effectively.

[0007]

OBJECTS OF THE INVENTION Accordingly, one object of the present invention is to provide an ATM
Is to realize the copy of the broadcast cell in the same method and the small circuit scale as the normal cell without complicating the copy processing. Another object of the present invention is to obtain header conversion information at high speed with a small memory capacity by effectively using a memory when converting the header of a copy cell.

[0008]

The broadcast cell copy system of the present invention comprises a plurality of input / output line corresponding units and a switch unit.
In an ATM switch device having a function of transmitting a back pressure signal from an output line corresponding unit and a function of copying a cell to an input / output line corresponding unit in a switch unit, the output line corresponding unit performs processing according to the priority added to the cell. Level recognition function, a copy function for performing cell copy and back pressure processing based on cell copy number information added to a cell, and a header conversion for replacing a cell information identifier with a new cell information identifier based on the cell copy information and cell information identifier added to a cell. Function.

According to a preferred embodiment of the broadcast cell copy method of the present invention, the header conversion function divides a table area of a broadcast copy target cell and a normal cell. In the table of the broadcast copy target cell and the normal cell divided by the header conversion function, a new cell information identifier is set to the continuous address of the table by the number of times of copying the broadcast copy target cell. If the header conversion function recognizes the cell as a broadcast copy target cell, the header conversion information for use in the broadcast processing is collectively cached in the header conversion function when accessing the first time. . The copy function includes a queue control function, a queue buffer for storing received ATM cells and reading in accordance with a read instruction from the queue control function, and taking in one cell from the queue buffer according to the instruction of the queue control function until the next take-in instruction is received. It has a one-cell buffer for holding. The queue control function has a plurality of threshold values of the number of staying cells at which the queue control function sends status information according to the number of ATM cells staying in the queue buffer. Further, the queue buffer is a FIFO memory.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and operation of a preferred embodiment of a broadcast cell copy system according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a preferred embodiment of a broadcast cell copy system according to the present invention.
This broadcast cell copy method uses the input buffer 1
A plurality of line corresponding units (inputs) 10a to 10z having 1;
The switch unit 20 includes a switch (SW) copy function 21 and a plurality of line corresponding units 30a to 30z. Each line corresponding unit (output) 30 has a level recognition function 3
1, a copy function 32, a header conversion function 33, an output buffer unit 34, and a line output unit 35.

Next, the preferred embodiment of the broadcast cell copy system shown in FIG. 1 is roughly divided into a SW unit 20 and a plurality of line corresponding units 10, 30 (10a to 10z, 30a to 3 in the figure).
0z). Line handling units 10, 3
0 is a line corresponding unit (input) 10 (that is, 10a to 10z) and a line corresponding unit (output) for convenience of explanation.
30 (that is, 30a to 30z). In addition, since the line corresponding units 10 and 30 have a common configuration for the sake of explanation, each line corresponding unit (input) 10 has a line corresponding unit.
(Input) 10a is explained as a representative, and each line corresponding part (Output)
30 will be described using the line corresponding unit (output) 30a as an example.

Each component in this embodiment is shown in FIG.
This will be described with reference to FIG. The line corresponding unit (input) 10a has an input buffer unit 11 inside. However, in the line corresponding section (input) 10a, portions not directly related to the present invention are omitted. The SW unit 20 has an internal SW
It has a copy function 21. However, also in the SW unit 20, parts that are not directly related to the present invention are omitted. As described above, the line corresponding unit (output) 30a internally includes the level recognition function 31, the copy function 32, and the header conversion function 3.
3, having an output buffer 34 and a line output unit 35;
However, also in the line corresponding section (output) 30a, parts that are not directly related to the present invention are omitted.

FIG. 2 shows a detailed configuration of the line corresponding unit (output) 30a shown in FIG. The copy function 32
It has a copy control 321 and a priority control function 322. However, in the copy function 32, portions not directly related to the present invention are omitted. Header conversion function 3
3 is an HT (header) conversion and copy control function 331
And an HT memory function 332. However, parts of the header conversion function 33 that are not directly related to the present invention are omitted.

FIG. 5 shows a detailed configuration of the copy control 321 shown in FIG. 2 together with its peripheral components. In FIG. 5, the copy control 321 has a queue control function 323, a queue buffer 324, and a one-cell buffer 325. However, in the copy control 321, portions not directly related to the present invention are omitted. Here, the queue control function 323, the queue buffers 324 and 1
Cell buffers 325 are interconnected. The queue control function 323 includes an HT conversion and copy control function 331.
It is connected to the. The queue buffer 324 is connected to the level recognition function 31 described above. The one-cell buffer 325 is connected to the priority control function 322.

Next, a description will be given of the connection relations, functions, and the like of the components constituting the preferred embodiment of the broadcast cell copy system according to the present invention. First, in FIG. 1, a line corresponding unit (input) 10 includes a line for externally inputting ATM cell information or non-ATM cell information, a cell information input line for sending an ATM cell to the SW unit 20, and a SW unit 20. Is connected to the back pressure information line. The SW unit 20 includes a cell information input line from each line corresponding unit (input) 10a to 10z, a back pressure information line for each line corresponding unit (input) 10a to 10z, and a line corresponding unit (output) 30a to 30z.
z: Cell information output line and each line corresponding unit (output) 30a
-30z are connected. The line corresponding unit (output) 30 includes a cell information output line for receiving cells from the SW unit 20, a back pressure information line for the SW unit 20, and a line for outputting ATM cell information or non-ATM cell information to the outside. Is connected. The connection relationship of the internal configuration example in the line corresponding unit (output) 30 will be described. A cell information output line from the SW unit 20 and a cell information line to the copy function 32 are connected to the level recognition function 31.

The copy function 32 includes a level recognition function 31
, A cell information line to the header conversion function 33, and a back pressure information line to the SW unit 20. The cell information line from the copy function 32 and the cell information line to the output buffer unit 34 are connected to the header conversion function 33. The cell information line from the header conversion function 33 and the cell information line to the line output unit 35 are connected to the output buffer unit 34. The line output unit 35 is connected to a cell information line from the output buffer unit 34 and a line for outputting to the outside.

Next, in FIG. 2, the copy control 321 includes a cell information line from the level recognition function 31 and the SW unit 20.
And a cell information line to the priority control function 322. A cell information line from the copy control 321, a read control line from the HT & copy control function 331, and a cell information line to the HT & copy control function 331 are connected to the priority control function 322. The HT & copy control function 331 includes copy control 3
21, a cell information line from the priority control function 322, an address / data / control signal with the HT memory function 332, and a cell information line to the output buffer unit 34.

In FIG. 5, the queue buffer 32
4, a cell information line from the level recognition function 31, a control signal / state information line with the queue control function 323, and a cell information line to the one-cell buffer 325 are connected. 1
To the cell buffer 325, a cell information line from the queue buffer 324, a control line from the queue control function 323, and a cell information line to the priority control function 322 are connected.

Next, the operation of the preferred embodiment of the broadcast cell copy system according to the present invention will be described with reference to FIGS. First, the function of each component will be described. Line handling unit 1
At 0 and 30, for simplicity of explanation, the interface with the external line is an ATM cell interface. In the case of the non-ATM cell interface, the line handling units 10 and 30 add a process of converting non-ATM information into cells / de-cells as a process in the line handling units 10 and 30.

The line corresponding unit (input) 10 temporarily stores ATM cells input from an external line in the input buffer unit 11. In this case, the ATM cell information identifier (VPI /
Based on preset priority information (for example, ATM cell service class), destination information, and broadcast information searched by VCI or the like, a corresponding queue buffer in the corresponding input buffer unit 11 is assigned a priority. And add the information. The ATM cells stored in the input buffer unit 11 are transmitted to the SW unit 20 according to the priority. However, when the back pressure information is received from the SW unit 20, the transmission of the ATM cell to the corresponding route (or line) is suspended until the back pressure information is released, and the ATM cell which does not correspond to the back pressure information is transmitted. Only sent.

The SW unit 20 includes a line corresponding unit (input) 10a-
The ATM cell received from 10z is switched to the corresponding line corresponding units 30a to 30z according to the destination route information. At this time, if the ATM cell to be switched is a broadcast cell, it is copied by the SW copy function 21 and transmitted to the corresponding line corresponding unit (output) 30. If the SW unit 20 is an output buffer type switch, no special function is required as the SW copy function 21 and the switch unit 20 may distribute the output to output buffers corresponding to a plurality of broadcast destinations in the switch. In the SW unit 20, each line corresponding unit
(Output) When the back pressure information output from 30a to 30z is received, certain processing is performed,
(Input) Send back pressure information to 10a to 10z.

The level recognition function 31 distributes the ATM cells received from the SW section 20 to the corresponding queue buffers 324 in the copy function 32 based on the priority information added to the ATM cells. The queue buffer 324
When an M cell is received, it is accumulated and the queue control function 3
It is read in accordance with a read instruction from 23. When the number of ATM cells staying in the queue buffer 324 exceeds a preset number, the status information is sent to the queue control function 323. At this time, it is desirable that the threshold value of the number of staying cells has a plurality of levels. Further, it is desirable that the queue buffer 324 be constituted by a FIFO (first in first out) memory. The one-cell buffer 325 stores the queue buffer 32 according to an instruction from the queue control function 323.
It takes in one cell from four and keeps holding the contents until the next fetch instruction is received (corresponding to a register).

Further, it detects the broadcast cell information (copy count number other than 0) added to the ATM cell, sends a read request to the priority control function 322, and reads until the copy count number becomes 0. Continue sending requests. The copy count number is decremented by one each time it is read from the priority control function 322. The queue control function 323 receives an instruction from the HT conversion & copy control function 331 and sends a fetch instruction to the one-cell buffer 325. Further, the queue control function 323 issues a read / write instruction to the queue buffer 324, receives the status from the queue buffer 324, generates back pressure information, and transmits the back pressure information to the SW unit 20. Priority control function 322
Receives a read request from a plurality of copy controls 321, reads from the highest priority copy control 321, and sends it to the HT conversion & copy control function 331.

In the preferred embodiment, the priority control method is a combination of the fixed priority and the rotation priority. However, the priority method is not limited. The HT conversion & copy control function 331 is the ATM received from the priority control function 322.
HT by a predetermined method from the cell information identifier
The address for the memory function 332 is calculated. Then, it accesses the HT memory function 332 to obtain header information, changes the information identifier of the ATM cell, and transmits the ATM cell to the corresponding queue of the output buffer unit 34 in accordance with its priority. The content / form of the information set in the HT memory function 332 is exemplified in FIGS. When the received ATM cell is a broadcast cell, the HT conversion & copy control function 331 calculates a broadcast header information address based on the copy count value k and the calculated broadcast area address, and accesses the HT memory function 332. I do.

Next, an outline of the overall operation of the broadcast cell copy system shown in FIG. 1 will be described. The ATM cell received from the external line is the ATM cell to which destination line corresponding part information or broadcast information obtained by the ATM cell information identifier in the line corresponding part (input) 10 is added according to its priority. The data is temporarily stored in the input buffer unit 11. The ATM cells staying in the input buffer unit 11 are sent to the SW unit 20 according to the priority order. The SW section 20 sends the ATM to the corresponding destination line corresponding section (output) 30 based on the information added to the ATM cell.
Send the cell.

At this time, if the corresponding cell is a broadcast cell, the SW copy function 21 transmits the broadcast cell to a plurality of corresponding line corresponding units 30. Line corresponding part (output) 3
The ATM cell received at 0 is transferred to the queue buffer 324 of the copy function 32 according to the priority at the level recognition function 31.
Is accumulated in AT stored in the queue buffer 324
In response to an instruction from the queue control function 323, the M cell
The cells are transferred to the one-cell buffer 325. The one-cell buffer 325 checks the copy count added to the ATM cell, and sends a read request to the priority control function 322 if it is not 0. Priority control function 3
At 22, the ATM cell is read from the one-cell buffer based on the priority and transmitted to the header conversion function 33. The header conversion function 33 obtains a new header from the information identifier of the received ATM cell, replaces the new header, and replaces the new header.
Send to 4. In the output buffer unit 34, the data is temporarily stored in a queue buffer corresponding to the priority, and transmitted to the line output unit 35 according to the priority control in the output buffer.

As described above, according to the present invention, since the processing of the normal cell and the processing of the broadcast copy cell are basically realized with almost no change in the processing contents, the broadcast cell copy system which can simplify the circuit configuration is provided. can get.

By changing the above-described preferred embodiment to include a cache function in the HT memory function 332, two accesses to the HT memory at the time of broadcasting can be made only at the first access, and At the time of access, processing can be performed by one HT access, as in the case of a normal cell, so that the speed can be increased.

The configuration and operation of the preferred embodiment of the broadcast cell copy system according to the present invention have been described in detail. However, it should be noted that such an embodiment is merely an example of the present invention and does not limit the present invention in any way. It will be readily apparent to those skilled in the art that various modifications can be made in accordance with the particular application without departing from the spirit of the invention.

[0031]

As will be understood from the above description, the broadcast cell copy system of the present invention has the following remarkable practical effects. First, the broadcast cell copy has a simple configuration. The reason is that, in the processing of the normal cell and the broadcast cell, the copy control is realized in substantially the same manner as the handling of the normal cell. Second, the HT memory can be used effectively. The reason is that since the header information storage method in the HT memory is managed by dividing it into a single area and a broadcast area, no useless memory area is generated in a normal cell. Third, cell copying within the same line is simple. The reason for this is that the content of the one-cell buffer 325 is not updated by the copy function 32 at the time of a broadcast copy cell, and processing can be performed in the same manner as a normal cell. Fourth, a broadcast cell copy function can be realized with a small buffer memory capacity. The reason is that a queue buffer for broadcast copying is not required.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a preferred embodiment of a broadcast cell copy system according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a line corresponding unit (output) shown in FIG.

FIG. 3 is an example of assignment of an HT memory function shown in FIG. 2;

FIG. 4 is an example of header information.

FIG. 5 is a block diagram showing a detailed configuration of the copy control shown in FIG. 2 together with its peripheral configuration.

FIG. 6 is a block diagram showing a configuration of a conventional broadcast communication system.

7 is an example of memory allocation of an HT memory function in the conventional broadcast communication system shown in FIG.

[Explanation of symbols]

 10a-10z Input line corresponding unit 11 Input buffer unit 20 Switch (SW) unit 21 SW copy function 30a-30z Output line corresponding unit 31 Level recognition function 32 Copy function 321 Copy control 322 Priority control function 323 Queue control function 324 Queue buffer 325 1-cell buffer 33 Header conversion function 331 HT conversion & copy control function 332 HT memory function 34 Output buffer unit 35 Line output unit

Claims (7)

[Claims] A function of transmitting a back pressure signal from said output line corresponding unit to an input buffer of said input line corresponding unit, said switch unit comprising a plurality of input / output line corresponding units and a switch unit; An ATM switch device having a function of copying a cell to said input / output line corresponding unit, wherein said output line corresponding unit has a level recognition function for processing according to the priority assigned to the cell, and a cell copy added to said cell. A copy function for performing cell copy and back pressure processing based on number information; and a header conversion function for replacing a cell information identifier with a new cell information identifier based on the cell copy information and cell information identifier added to the cell. Report cell copy method. 2. The broadcast cell copy method according to claim 1, wherein said header conversion function separates a table area of a broadcast copy target cell and a normal cell. 3. In a table of a broadcast copy target cell and a normal cell divided by the header conversion function, the broadcast copy target cell is stored in a continuous address of the table by the number of times of copying, and the new cell information identifier is stored in the continuous address of the table. 3. The broadcast cell copy method according to claim 1, wherein 4. When the header conversion function recognizes a cell to be broadcast-copied, the header conversion information for use in the broadcast processing is collectively referred to as the header conversion information when the first access is made. 2. The broadcast cell copy method according to claim 1, wherein caching is performed in a conversion function. 5. The copy function includes a queue control function, a queue buffer for storing received ATM cells and reading them out according to a read instruction from the queue control function, and taking in one cell from the queue buffer according to an instruction of the queue control function. 3. The broadcast cell copy method according to claim 1, further comprising a one-cell buffer for holding until a next fetch instruction is received. 6. An AT staying in the queue buffer
6. The broadcast cell copy method according to claim 5, wherein the queue control function has a plurality of threshold values of the number of staying cells for transmitting status information according to the number of M cells. 7. The queue buffer according to claim 5, wherein said queue buffer is a FIFO (first in first out) memory.
Broadcast cell copy method described in 1.