JPH04137941A - Atm traffic line concentrator system - Google Patents

Abstract

PURPOSE:To flexibly decide a line concentration ratio by assigning a time slot to each input line and applying time division multiplex to a data. CONSTITUTION:Input lines 001-003 are accommodated respectively in input cell buffers 111-113. A time division multiplex circuit 201 gives an output to an output line 101 at a transmission speed of nearly 150Mbit/s the same speed as that for each input line. A frame memory 301 is a memory having n-sets of time slots for one frame and controls a time division multiplex circuit 201. The assignment of a time slot for each of the input cell buffers 111-113 is implemented for each call or semi-fixedly by taking the traffic characteristic of each of the input lines 001-003 into account.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ATM traffic concentration system, and in particular to an ATM traffic concentration system.
(Asynchronous transfer mode) This relates to a line concentration method that accommodates a large number of lines with low traffic efficiency that carry cells and concentrates them into a high efficiency line.

[Conventional technology]

Conventionally, traffic concentration using the ATM method, which is said to be the ultimate solution to wideband ISDN and statistically multiplexes and exchanges fixed-length and short packets on a cell-by-cell basis, has been achieved by connecting multiple ATM switches in series and concentrating the traffic. Another method is to reduce the physical transfer rate of a low-efficiency traffic line, perform time division multiplexing, and then convert the data into ATM cells.

[Problem to be solved by the invention]

In the ATM method, the physical transfer speed is approximately 150Mbit/
Since the unit is a high-speed line called s, the voice traffic that can be considered as the main traffic is 64 kbit/
s, it is necessary to efficiently concentrate the lines by about 1/2,000. Furthermore, it is necessary to make the line concentration ratio variable in order to flexibly handle broadband traffic.

Among the conventional methods mentioned above, if you try to vary the concentration ratio from 1/2,000 to a fraction of a fraction by using an ATM switch, you will end up with an A of 2.0OOX2,000.
There is no choice but to use a TM switch, and the economic effect of concentrating the lines cannot be obtained.

Furthermore, the ATM cell formation method and subscriber access line after low-speed time division multiplexing do not provide the advantage of free bandwidth that ATM has.

[Means to solve the problem]

The ATM traffic concentration method of the present invention is an ATM traffic concentration method in which n input lines carrying ATM cells are concentrated into one output line.
an input cell buffer for temporarily storing cells; and a frame memory for storing a correspondence between the number of time slots of one frame of the output line, which are time-divided into n pieces, and the number of each of the input lines; - The correspondence between the time slot number of the memory and the input line number is set for each call or semi-fixedly, and the frame memory is referred to for each time slot and the ATM cell of the corresponding input line is retrieved from the input cell buffer. The configuration is such that the data is read out and output to the output line.

Further, in the above configuration, an empty cell generation circuit may be provided, and an empty cell may be output to a time slot to which a corresponding input line is not assigned.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. Each input line 001 to 003 has a capacity of approximately 150 Mbit/
ATM cells are carried at a transmission rate of 100 s, and are accommodated in each of input cell buffers 111 to 113. The number of input cell buffers 111 to 113 may be one cell, or the buffer capacity may be increased to fill the difference between the traffic characteristics that can be carried in the secured time slot and the traffic characteristics that are actually input. multiplex circuit 20
1 time-division multiplexes the cells in the input cell buffers 111 to 113 and outputs them to the output line 101 at the same transmission speed of about 150 Mbit/S as each input line. Empty cell generation circuit 21
1 inserts empty cells during time slots when there are no cells to output. The frame memory 301 is a memory having one frame and n time slots, and controls the time division multiplexing circuit 201.

Cells in each input cell buffer 111-13 are read out to output line 101 only during specified time slots. Time slot allocation for each human cell buffer 111 to 113 is done for each call or semi-fixedly, taking into account the traffic characteristics of each input line 001 to 003. From ~003 onwards, a circuit that performs signal processing by dropping signal cells is required.

In the case of semi-fixed time slots, multiple time slots may be assigned to one input port that is written offline from the operation console, and the intervals may be equal or variable.

FIG. 2 shows the structure of the frame memory 301 in FIG. 1, which has addresses 0 to n and always cycles in synchronization with the time slot period. Only one input cell buffer gate is opened during one time slot period.

FIG. 3 shows the concept that cells in each input cell buffer 111-113 are time-division multiplexed. Input line 001 is assigned time slot 1, and input line 002 is assigned time slots 0 and 3. Multiplexed cells are output onto the output line 101. Cells indicated by U are empty cells.

[Effects of the Invention] As explained above, the present invention makes it possible to create an economical ATM traffic concentrator that can flexibly determine the concentration ratio by allocating time slots to each input line and performing time division multiplexing. can.

Furthermore, in an ATM switch, incoming traffic regulation control is required to prevent switch resource congestion due to input traffic characteristics that behave freely. By installing the line concentrator according to the present invention in front of the ATM switch distribution stage, it is also possible to regulate the traffic input to the ATM switch network.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a frame memory, and FIG. 3 is a conceptual diagram showing how each input cell buffer is time-division multiplexed. 001-003...Input line, 101...Output line, 111-113...Input cell buffer, 201...
- Time division multiplexing circuit, 211...Empty cell generation circuit, 30
1...Frame memory.

Claims (1)

[Claims] 1. In an ATM traffic concentration method in which n input lines carrying ATM cells are concentrated into one output line, an input cell buffer temporarily stores ATM cells for each input line, and n frames of one frame of the output line. a frame memory for storing the correspondence between the number of time slots time-divided into each input line and the number of each of the input lines;
The correspondence between the time slot number of the memory and the input line number is set for each call or semi-fixed, and the ATM cell of the corresponding input line is retrieved from the input cell buffer by referring to the frame memory for each time slot. An ATM traffic concentration system characterized in that reading is output to the output line. 2. The ATM traffic concentration system according to claim 1, further comprising an empty cell generation circuit and outputting empty cells to time slots to which no corresponding input line is assigned.