JP2870518B2 - Cell separation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell separation system, and more particularly to reading out cells and route information from a buffer, and using a plurality of first data via a data bus based on the route information.
In First Out Memory (hereinafter "FIF")
O ". The present invention relates to a cell separation method in which a cell can be separated for each route by writing the cell in a cell, and a cell in another route can be prevented from being lost when a failure in a specific route occurs.

[0002]

2. Description of the Related Art Conventionally, in a system such as an ATM transmission system in which data is handled in units of cells and cells having different pieces of route information are transmitted by bus, cells having a plurality of pieces of route information are sequentially input and passed through a buffer. The switching or branching unit which outputs the data from the buffer requires a cell separation function of transmitting the cell read from the buffer to the output path via the bus.
As such a cell separation method, a plurality of FIFOs for distributing and storing cells on the output side of the buffer in accordance with the route are provided in the second.
Has been proposed.

As described above, in a system in which a cell is separated into a plurality of routes by reading cells and route information from a buffer and writing cells into one of a plurality of FIFOs based on the route information, In some cases, the FIFO read control process cannot catch up with the write control process, and the FIFO is temporarily filled with cells. In such a case, the FIFO write control unit controls the FIFO write control unit to avoid cell loss. It is also conceivable to stop reading of the route information and control so that the cells are not written in the FIFO, and to store the subsequent cells in the buffer.

[0004]

In the above-described cell separation method, even when a certain FIFO becomes full, the full state is temporary and the cell is immediately restored to a normal state having an empty area. In such a case, the input cells during that time can be stored in the buffer within the range of the storage capacity, so that the loss of the cells can be avoided.

[0005] However, in the above-mentioned cell separation system, the FIF
If the FIFO becomes full for a long period of time, such as when a failure occurs in the O read control unit and the FIFO cannot be read, buffer overflow will occur and input cells will be discarded and a failure will occur. There is a problem in that cells having route information other than the route are also lost.

An object of the present invention is to provide a cell loss avoidance method capable of avoiding the loss of cells on the other path even when a long-term failure state of a specific path occurs in cell separation.

[0007]

According to a cell separation method of the present invention, a cell read from a buffer via a bus is written into a plurality of FIFOs for each path to separate the cells. When any of the FIFOs is temporarily full, reading of cells from the buffer is temporarily stopped. When any of the FIFOs is long-term full, reading of cells from the buffer is continued and the corresponding path is stopped. Cells are avoided by discarding the cells.

In the above-mentioned cell separation system, a control unit for reading cells for each route from the plurality of FIFOs is provided. Long-term full state. Further, in the cell separation method, when a read failure in any one of the routes in the control unit continues for a certain period of time, the FIFO of the route is set to the long-term full state.

More specifically, the present invention relates to a buffer for input cells, a plurality of FIFOs for each route connected to the buffer by bus, and a method for reading cell and route information from the buffer and indicating the route information. First write cell to FIFO of path
And a second unit that reads cells from the FIFO for each route.
Wherein the FIFO outputs a full signal when the memory cell is full, the second control unit outputs a communication disconnection signal when a read failure occurs, and the first control unit Based on the full signal and the communication disconnection signal, if no communication disconnection signal is output and any one of the FIFO full signals is output, the reading of the cell and the route information from the buffer is stopped, and the communication disconnection is stopped. When any of the signals is output, the cell and the route information are continuously read from the buffer regardless of whether or not the FIFO full signal is output, and the cell having the failed route information is written into the FIFO. To avoid cell loss.

(Action) If a fault occurs in a certain route and the FIF
When O becomes full for a long period of time, cells having the route information in which a fault has occurred are discarded, thereby avoiding the loss of cells on the other route due to the influence of the fault in the route.

[0011]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention. This embodiment mainly includes a buffer 1, a FIFO write control unit 2, n FIFOs 3 to 4, and n FIFO read control units 5 and 6. The buffer 1 is a buffer having a predetermined storage capacity for sequentially writing input cells and reading out the written cells to a plurality of FIFOs 2 for each path.

The FIFO write control unit 2 sends a buffer read signal 10 to the buffer 1 and receives cell route information 11 and read data 12 from the buffer 1.
In addition, the FIFO write control unit 2 includes n FIFOs 3
4 through 4 via the data lines connected to the bus, and based on the route information 11, the F corresponding to one FIFO out of n routes.
The FIFO write signals 13 and 14 are sent out to
The write data 15 and 16 are written in the FO.

N FIFO read control units 5 and 6
Converts the FIFO read signals 21 and 22 into FI
By transmitting to the FOs 3 and 4, the read data 1
9 to 20 are received and cells for each route are output.

As described above, the cell read from the buffer is written into one of the n FIFOs 3 to 4 by the route information 11, and then the read control units 5 to 6
, Cells are separated into n routes by reading from n FIFOs.

Next, in the present embodiment, the n FIFOs have a function of monitoring the storage amount of the memory cells. When the memory cells are full, the FIFO full signals 17 and 18 are written to the FIFO. It is sent to the control unit 2. Also,
The FIFO readout control units 5 and 6 have a function of constantly monitoring their operation states. For example, when an abnormal state such as a failure of a data readout control CPU in the control unit occurs, a communication disconnection signal is output. 23 and 24 are sent to the FIFO write control unit 2.

In the FIFO write control unit 2, n F
FIFO full signals 17-18 from the FIFO and n F
In accordance with the reception status of the communication disconnection signals 23 and 24 from the IFO read control units 5 and 6, write control to the FIFO of each path is performed.

First, the FIFO write control unit and the FIFO
The configuration of the O read control unit will be described in detail.

FIG. 2 is a configuration diagram of the FIFO write control unit. The control unit mainly includes a FIFO write control unit 10.
0, failure detection unit 101 and buffer read control unit 1
02.

The buffer read control means 102 includes FIFO full signals 21 to 22 for notifying the fullness of the FIFO output from the FIFOs of the respective routes, and the occurrence of faults in the respective routes output from the FIFO read control units of the respective routes. Of the buffer read signal 10 to the buffer 1 is controlled based on the communication disconnection signals 23 and 24 for notifying the communication disconnection.

A method for generating the buffer read signal 10 for the buffer 1 will be described below.

When the communication disconnection signal and the FIFO full signal are all OFF (normal state), the buffer read signal is turned ON (output state) to read the buffer.
If the communication disconnection signals are all OFF (normal state) and any one of the FIFO full signals is ON (full state) and the FIFO for that path is temporarily full, the buffer read signal is turned OFF (non-output state). ) To stop reading the buffer. If one of the communication disconnection signals is turned ON (abnormal state) and the FIFO of the route becomes full for a long time, the FIFO full signal of the failed route is masked (disabled) to buffer the signal. The reading from the buffer is continued while preventing the reading from being stopped.

Further, the failure detecting section 101 detects a path in which a failure has occurred by receiving the communication disconnection signals 23 to 24 from the respective paths, and notifies the FIFO writing control means 100 of the failure occurrence path. The fault information 110 is output for the purpose. The FIFO write control means 100 outputs FIFO write signals 13 and 14 for writing cells to the FIFO corresponding to the route information based on the route information 11 output from the buffer. When the failure information 110 is generated from the unit 101, for example, the FIFO for the FIFO of the
By stopping the transmission of the O write signal, the cell having the route information of the route in which the fault has occurred is discarded.

FIG. 3 is a configuration diagram of the FIFO read control unit. The control unit mainly includes a FIFO read monitoring unit 20.
0, FIFO read control means 201.

The FIFO read control means 201 is a
By outputting the data read signal 21 to the FO,
The read data 19 is received from the IFO. The FIFO read monitoring unit 200 is provided with the FIFO read control unit 20.
1 and outputs a monitoring signal 210 to read control means 2
The read control unit 201 is monitored by detecting the response signal 211 received from the control unit 201.

The FIFO read monitor 200 includes, for example, a response signal 2 output from the read controller 201.
11 cannot be detected, it is determined that a fault has occurred and the FIF
The communication disconnection signal 23 output to the O write control unit is turned ON (abnormal state).

Next, another embodiment of the present invention in which the number n of routes is two will be described with reference to FIG. This embodiment mainly includes a buffer 1, a FIFO write control unit 2,
FIFO 3 for route 1, FIFO 4 for route 2, F for route 1
It comprises an FIFO read control unit 5 and a FIFO read control unit 6 for the route 2.

The FIFO write control unit 2 includes a FIFO 3
Notifying the fullness of the FIFOs output from and 4.
O full signals 17 and 18 and FIFO read control unit 5
Communication disconnection signal 2 for notifying the occurrence of failure output from
The buffer read signal 10 output to the buffer 1 is controlled by the four signals 3 and 24.

The FIFO write control unit 2 further includes a route information 11 read from the buffer 1 by the buffer read signal 10 and a communication disconnection signal 23 for the route 1 and the route 2.
And generating the FIFO write signals 13 and 14 for the route 1 and the route 2 from the fault information based on the ON / OFF state of the switches 24 and 24, and performing the cell write control to the FIFOs of the route 1 and the route 2. Separates the cell into two routes.

FIG. 5 is a diagram showing a method of controlling cell writing to the FIFO.

The communication disconnection signals of the two routes are both OFF.
(Normal state), and when the FIFO full signals of the two routes are both OFF (non-full state), the buffer read signal is turned ON (read state) and the FIFO
The write control unit acquires the cell and the route information and separates the cells based on the route information. Similarly, the communication disconnection signals of the two routes are both OFF, but when either of the FIFO full signals of the two routes is ON, the buffer read signal is turned OFF (read stop state). Then, the separation of the cell is stopped without acquiring the cell and the route information.

When one of the communication disconnection signals of the two routes is ON (failure state), the FIFO full signal of the route in which the failure has occurred is masked (disabled) and the failure is eliminated. If the FIFO full signal of the route where no fault has occurred is OFF (non-full status), the buffer read signal is turned ON (read status) to obtain the cell and route information, and for the route where no fault has occurred. Performs the cell separation, and discards the cell in the route where the failure has occurred.

Next, the FIF of the route where no fault has occurred
When the O full signal is ON (full state), the buffer read signal is turned OFF (stop reading), the cell and the route information are not obtained, and the separation of the cell is stopped.

Further, when the communication disconnection signals of the two routes are both ON, regardless of the FIFO full signal, the buffer read signal is turned ON (read state) to obtain the cell and route information. The cell is discarded also in the route.

In the embodiment of the present invention described above, an example has been described in which it is determined whether the FIFO full state is temporary or long-term based on the failure information of the control unit. If the long-term full state occurs due to another cause, such as a device other than the FIFO readout control unit, information on the device or the like can be used. A monitoring function is provided in the FIFO itself to determine whether the full state of the FIFO is temporary or long-term, or the FIFO or the FIFO write control unit is configured to measure with a timer or the like.
Obviously, it may be possible to determine the state related to the fullness of.

[0035]

According to the cell separation system of the present invention, the FIF
Since a cell separation operation is performed by detecting, for example, a failure in the FIFO read control unit, which causes a temporary full state and a long-term full state of O, the FIFO read control processing of a certain path is performed. If the FIFO cannot keep up with the write control process and the FIFO is temporarily filled with cells, the reading of cells and route information from the buffer is stopped, and subsequent cells are stored in the buffer. In order to avoid cell loss, and in the case of a failure in the read control unit of the FIFO, etc., the cell read from the buffer is continued and the long-term FIFO full path is discarded, thereby causing a failure. Since it is possible to avoid that even cells having route information of a route where no route has occurred are lost,
The effect is remarkable in that the reliability of the system is improved.

[0036]

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a route failure detection type other-way cell loss avoidance system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a FIFO write control unit of a route failure detection type other-side cell loss avoidance method according to the present embodiment.

FIG. 3 is a diagram illustrating a configuration of a FIFO read control unit of a route failure detection type other-side cell loss avoidance method according to the present embodiment.

FIG. 4 is another embodiment of the route failure detection type other-side cell loss avoidance method of FIG. 1;

FIG. 5 is a diagram showing the contents of control in the present embodiment.

[Explanation of symbols]

 1 Buffer 2 FIFO write control unit 3, 4 FIFO 5, 6 FIFO read control unit 10 Buffer read signal 11 Route information 12 Read data 13, 14 FIFO write signal 15, 16 Write data 17, 18 FIFO full signal 19, 20 Read Data 21, 22 FIFO read signal 23, 24 Signal cutoff signal 100 FIFO write control means 101 Failure detection unit 102 Buffer read control means 110 Failure information 200 FIFO read monitoring unit 201 FIFO read control means 210 Monitoring signal 211 Response signal

Claims (4)

(57) [Claims] 1. A cell separation method for separating cells by writing cells read from a buffer via a bus to a plurality of FIFOs for each route, wherein when any of the plurality of FIFOs is temporarily full. Reading of cells from the buffer is temporarily stopped and FI
A cell separation method in which when any of the FOs is in a long-term full state, reading of cells from the buffer is continued and cells in the corresponding path are discarded to avoid cell loss. 2. A control unit for reading cells for each route from the plurality of FIFOs, and when a failure occurs in reading of any one of the routes by the control unit, the FIFO of the route is regarded as the long-term full state. 2. The cell separation method according to claim 1, wherein: 3. When a read failure of any one of the routes in the control unit continues for a certain period of time, a FIFO of the route is used.
3. The cell separation method according to claim 2, wherein the state is regarded as the long-term full state. 4. A buffer for input cells, a plurality of FIFOs for each route bus-connected to the buffer, and cells and route information are read from the buffer and written to the FIFO of the route indicated by the route information. A first control unit; and a second control unit for reading cells from the FIFO for each route, wherein the FIFO outputs a full signal when the storage cells are full, and the second control unit outputs a read failure signal. The first control unit outputs a communication disconnection signal when an occurrence occurs, and the first control unit does not output any communication disconnection signal based on the full signal and the communication disconnection signal.
If any one of the FIFO full signals is output, the reading of the cell and the route information from the buffer is stopped, and if any of the communication disconnection signals is output, regardless of whether the FIFO full signal is output or not. A cell separation method for continuously reading cells and route information from a buffer and stopping writing to a FIFO of a cell having failed route information to avoid cell loss.