JPH0568047A - Cell data multiplexer - Google Patents

Abstract

PURPOSE:To attain efficient asynchronous multiplex to cell data handled at a broad band ISDN of the asynchronous transfer system. CONSTITUTION:A temporary storage cell data quantity of FIFO memories 111-113 connecting to input ports 101-103 is detected by storage cell data quantity detection means 121-123. A maximum storage FIFO memory detection means 130 specifies an FIFO memory having largest storage cell data quantity and informs it to an FIFO memory data read means 140. The FIFO memory data read means 140 reads cell data from the FIFO memory having largest storage cell data quantity with priority, applies asynchronous multiplexing to the data and gives the result to an output port 104. Thus, the asynchronous multiplexing of the cell data is efficiently realized with less FIFO memory capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell data multiplexer for asynchronously multiplexing and outputting supplied fixed-length packet data (hereinafter referred to as cell data as necessary), and more particularly to an asynchronous transfer wideband ISDN. The present invention relates to a cell data multiplexer that asynchronously multiplexes cell data handled in 1.

[0002]

2. Description of the Related Art Conventionally, in this type of cell data multiplexing apparatus, the cell data supplied to each input port of the FIFO memory is controlled so that the cell data is given an equal priority.

FIG. 2 shows an example of the configuration of a conventional cell data multiplexer.

In this example, the cell data supplied to the input ports 201 to 203 are asynchronously multiplexed and output port 2
It is designed to be output from 04. First, the cell data supplied to the input ports 201 to 203 are temporarily stored in the FIFO memories 211 to 213. Next, FIFO
The memory data reading means 230 is the priority control means 2
The data in the FIFO memories 211 to 213 is selectively read out under the control of 20 and thereby the multiplexing of the cell data is realized.

The priority control means 220 in the conventional cell data multiplexer of the example of FIG. 2 has FIFO memories 211 to 213 from which cell data is read at a certain timing.
Controls to set the priority to the lowest at the next read timing. By such control, the priority order of the input ports 201 to 203 becomes equal.

[0006]

However, in the above-mentioned conventional cell data multiplexer, the FIFO memories 211 to 211 are not used.
Regardless of the amount of data stored in 213, the priority of each input port 201 to 203 is controlled to be equal. Therefore, when cell data momentarily concentrates on a specific input port, Connected FIFO
There is a problem in that an overflow may occur in the memory, and the efficiency of cell data multiplexing decreases.

It is an object of the present invention to provide a cell data multiplexer which can improve the efficiency of cell data multiplexing.

[0008]

The present invention comprises at least two aspects.
In a cell data multiplexer that asynchronously multiplexes cell data supplied to respective ones of two input ports and outputs from one output port, the supplied input cell data is temporarily connected to each of the above input ports. And a storage unit connected to each of the FIFO memories to detect the storage cell data amount stored in the FIFO memory, and to store the storage cell data amount detection unit. Maximum storage FIFO memory detection means for detecting the maximum storage cell data amount of the stored storage cell data amounts and identifying the FIFO memory having the maximum storage cell data amount, and the maximum storage FIFO memory detection means. Identified by F
A FIFO memory data reading means for reading cell data from the IFO memory and outputting the cell data from the one output port.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cell data multiplexer of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention.

In FIG. 1, an input port 1 for cell data
01 to 103 are FIFO memories 111 to 11 respectively.
3 is connected to the input side. FIFO memory 111 to 11
The accumulated data amount output terminal 3 is connected to the input side of the accumulated cell data amount detecting means 121 to 123. The cell data output sides of the FIFO memories 111 to 113 are connected to the data input terminal of the FIFO memory data reading means 140. The output sides of the storage cell data amount detection means 121 to 123 are connected to the input side of the maximum storage FIFO memory detection means 130. The output side of the maximum storage FIFO memory detecting means 130 is connected to the control input terminal of the FIFO memory data reading means 140. The output side of the FIFO memory data reading means 140 is the output port 1
It is connected to 04.

Next, the operation in this configuration will be described.

The FIFO memories 111 to 113 temporarily store cell data which are fixed length packet data input from the input ports 101 to 103. The accumulated cell data amount detecting means 121 to 123 are respectively the FIFO memory 1
The current storage statuses 151 to 153 of the current temporary storage cell data amount 11 to 113 are constantly monitored, and the storage cell data amount 1
Maximum storage FIFO memory detection means 130
Output to.

Maximum storage FIFO memory detection means 130
Detects the maximum storage cell data amount of the supplied storage cell data amounts 161 to 163, identifies the FIFO memory having the maximum storage cell data amount, and sets the maximum storage FIFO memory number 131 to FIFO. Notify the memory data reading means 140.

FIFO memory data reading means 140
Then, the cell data 171 to 173 are read from the corresponding FIFO memory according to the FIFO memory number 131 that specifies the FIFO memory having the largest amount of accumulated cell data sent from the maximum accumulated FIFO memory detection means 130, and output port The cell data multiplex output 141 asynchronously multiplexed with 104 is transmitted.

The cell data multiplexer of the example of FIG. 1 repeats the above-mentioned operation to input ports 101 to 1
Asynchronous multiplexing for cell data input from three ports 03 is realized.

[0017]

As is apparent from the above description, the cell data multiplexer of the present invention has the FI connected to the input port.
The amount of accumulated cell data in the FO memory is detected, and the cell data is preferentially read from the FIFO memory having the largest amount of accumulated cell data.

Therefore, there is an effect that asynchronous multiplexing of cell data can be efficiently realized with a small FIFO memory capacity.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a cell data multiplexing device of the present invention.

FIG. 2 is a block diagram showing a configuration of an example of a conventional cell data multiplexing device.

[Explanation of symbols]

 101-103 input port 104 output port 111-113 FIFO memory 121-123 accumulated cell data amount detection means 130 maximum accumulated FIFO memory detection means 131 maximum accumulated FIFO memory number 140 FIFO memory data reading means 141 cell data multiple output 151-153 FIFO memory accumulation state 161 to 163 accumulated cell data amount 171 to 173 cell data

Claims (1)

[Claims] 1. A cell data multiplexer that asynchronously multiplexes cell data supplied to each of at least two input ports and outputs from one output port, and is connected to each of the input ports and supplied. And a FIFO memory for temporarily accumulating the input cell data and each of the above-mentioned FIFO memories.
A storage cell data amount detecting means for detecting the storage cell data amount stored in the FO memory, and a storage cell data amount having the maximum value among the storage cell data amounts stored in the storage cell data amount detecting means. And a maximum storage FIFO memory detection unit that specifies a FIFO memory having the maximum storage cell data amount, and cell data is read from the FIFO memory specified by the maximum storage FIFO memory detection unit and output from the one output port. A cell data multiplexing device comprising: a FIFO memory data reading means for outputting;