JPH03267847A - Asynchronous multiplex transmitter - Google Patents

Abstract

PURPOSE:To connect the transmitter to an ATM network and to improve the line utilizing efficiency by combining information requesting periodic real time transmission, information requesting aperiodic real time transmission, and aperiodic information not requesting real time and applying multiplex transmission to the combined information while keeping time transparency. CONSTITUTION:The packet adaptor is provided with cell processing means 5-1-5-7, 1st output means 6-1, 6-2, 8-1, 2nd output means 6-3-6-5, 8-2, 3rd output means 6-6, 6-7, 8-3, and a multiplexer means 11. Then three kinds of information sets as periodic and real time information, aperiodic and real time information, and aperiodic and non-real time information are respectively processed into cells, and the periodic and real time information is outputted periodically, the aperiodic and real time information is outputted periodically when no real time information exists, and the aperiodic and non-real time information is outputted when no other kinds of information exists. Thus, while keeping different time transparency from each information source is maintained, the information is sent by utilizing an ATM exchange network.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for multimedia transmission in which different types of information are multiplexed and transmitted. In particular, asynchronous transmission mode (A
Synchronous Transfer Mod
It is used for multiplex transmission of different types of information using the switching network of ``ATMJ'' (hereinafter referred to as ``rATMJ'').

The present invention converts different types of information into cells and controls the transmission based on the periodicity and real-time nature of the information.
er Mode (hereinafter referred to as rsTMJ) switching network,
It accommodates a plurality of devices with different configurations, one for a packet switching network and one for an ATM switching network, and performs multiplex transmission.

[Conventional technology]

When transmitting information such as video information or data, different transmission methods are used depending on the usage form and amount of the information.

For example, video information requires real-time performance, and in the case of moving images, it is necessary to periodically transmit a certain amount of information. Such information is typically transmitted over an STM switched network and is periodically transmitted as a constant amount of information, ie, a fixed bit rate of information.

Billing is done for each line setting.

In the case of still images, although real-time performance is required, there is often no periodicity in information generation. Therefore, transmission using an ATM switching network that transmits aperiodic information may be considered.

Billing is done based on the amount of information generated. In order to multiplex such information, it is generally considered that the information is multiplexed in the order in which it occurs, but no clear method has been proposed at present.

For data that does not require much real-time performance or periodicity, a packet-switched network is generally used. In a packet-switched network, fees are charged based on the amount of information generated.

[Problem to be solved by the invention]

As described above, since the transmission form differs depending on the information, it has not been considered so far to accommodate different types of information all at once and multiplex it while maintaining time transparency.

The present invention solves these problems and provides a system for STM switching networks.
The purpose of the present invention is to provide an asynchronous multiplex transmission device that collectively accommodates devices for packet switching networks and ATM switching networks, and transmits information in cell units while maintaining time transparency when connecting to each switching network. shall be.

[Means to solve the problem]

The asynchronous multiplex transmission device of the present invention multiplexes three types of information: periodic and real-time information, non-periodic and real-time information, and aperiodic and non-real-time information to create an asynchronous switching network. In the asynchronous multiplex transmission device, the cell forming means for forming each of the three types of information into cells, and a first cell forming means for temporarily storing and periodically outputting the cell-formed periodic and real-time information, are provided. an output means, a second output means that temporarily stores cellularized aperiodic real-time information and outputs it when there is no output from the first output means; a third output means that temporarily stores non-real time information and outputs it when there is no output from both the first output means and the second output means; It is characterized by comprising a multiplexing means for multiplexing the pressures of the output means and the third output means. The asynchronous multiplex transmission device of the present invention is hereinafter referred to as "rATM packet adapter".

It is preferable that the second output means and the second output means include means for requesting the corresponding information source to stop generating information or change the amount of information generated when the amount of accumulated information increases. In this case, it is also possible to set priorities for the same type of information and output the information in order of priority.

[For production]

There are three types of information: periodic and real-time information such as moving image information, non-periodic and real-time information such as still image information, and non-periodic and non-real-time information such as data. Convert each piece of information into cells.

Regarding the three types of cell-formed information, periodic and real-time information is output periodically.

Aperiodic and real-time information is output when there is no periodic and real-time information. Aperiodic and non-real time information is output when there is no other type of information. In this way, information can be transmitted using an ATM switching network while maintaining time transparency that differs from one information source to another.

For information that may not be real-time, when the amount of accumulated information increases, it is possible to prevent information overflow by requesting the corresponding information source to stop generating information or change the amount of information generated.

[Embodiment] FIG. 1 is a block diagram of an asynchronous multiplex transmission apparatus according to an embodiment of the present invention.

The ATM packet adapter 4 multiplexes three types of information: periodic and real-time information, aperiodic and real-time information, and aperiodic and non-real-time information, and sends the multiplexed information to the asynchronous switching network. This is an asynchronous multiplex transmission device. In this example,
As a manual device for ATM packet adapter 4, 54k
Video converter 1 for STM switching network that outputs encoded video information of 1.128 kbps, video controller 2 for ATM switching network 2 to 2-3, and packets for ATM switching network that outputs encoded video information of 1.128 kbps. Switched network data transfer devices 3-1, 3-2 are connected, and the output is connected to an ATM switching network.

Here, the feature of this embodiment is that the ATM packet adapter 4 includes cell matching processing units 5-1 to 5-7 as cell forming means for forming cells of three types of information, respectively.
A FIFO buffer 6-1, 6-2 and a multiplex bus 8-1 are provided as a first output means for temporarily storing and periodically outputting cellular periodic and real-time information. FIFO buffers 6-3 to 6-5 and a multiplexer serve as a second output means for temporally storing the aperiodic and real-time information and outputting it when there is no output from the first output means. 8-2, which temporarily stores non-periodic and non-real time cell information and outputs it when there is no output from both the first output means and the second output means. FIFO buffer 6-6.6- as the third output means
7 and a multiplex bus 8-3, and a line interface 11 as a multiplexing means for multiplexing the outputs of the first output means, the second output means, and the third output means. Signal output operations from the FIFO buffers 6-1 to 6-7 and the multiplexed buses 8-1 to 8-3 are controlled by a logic operation section 9 and a control section 10.

The ATM packet adapter 4 further includes a monitoring circuit 7- as means for requesting the corresponding information source to stop generating information or change the amount of information generated when the amount of information stored in the FIFO buffers 6-3 to 6-5 increases. 1, and a monitoring circuit 7-2 as means for requesting the corresponding information source to stop generating information or change the amount of information generated when the amount of information stored in the FIFO buffer 6-6, 6-7 increases.

Here, the characteristics of information generation in each device connected to the ATM packet adapter 4 and the method of multiplexing the exchange details will be explained.

FIG. 2 is a diagram showing a method for multiplexing coded video information for an STM switching network, in which (a) shows n sequences of coded video information, and (b) shows the multiplexed output. Fig. 1 shows an example in which two STM exchange network video controllers 1.1-2 are connected to an ATM packet adapter 4, but here, as an example of a boat fishing, n-series encoding A case of multiplexing video information will be explained.

A video hub for an STM7M switching network requires real-time transmission of the encoded video information it outputs, and is charged for each line setting, so it periodically generates a fixed amount of information, that is, information at a fixed bit rate. At this time, each knob generates information periodically at constant intervals T+, as shown in FIG. 2(a).

Since the information generation cycle is constant, the bit string information from each block is shifted by one clock timing using a buffer or the like and multiplexed.

In this way, as long as the respective information generation intervals T1 and the time intervals of the same information after multiplexing can be kept equal, n pieces of STM7M switching network video communication information can be multiplexed.

FIG. 3 is a diagram showing a method of multiplexing data for packet exchange, in which (a) shows packets output from individual data transfer devices, and (b) shows multiplexed output.

Data transfer devices for packet-switched networks are not required to perform real-time transmission, so they aperiodically generate an indefinite amount of information packets. Billing is done based on occurrence information. Output packets P1 to P4 from each data transfer device are temporarily stored in a buffer and then multiplexed, for example, in the order of occurrence. There is no need to maintain the interval between packets generated from the same data transfer device even after multiplexing; for example, the interval T2 between packets P1 and P2 before multiplexing and the interval T after multiplexing.

, it is not necessary that T3=T2.

Since video transmission for ATM switching networks requires real-time transmission and is billed for the amount of information generated, a variable bit rate configuration in which information of a constant cell length is generated aperiodically is conceivable.

In order to handle these three types of information all at once, the first
The ATM packet adapter 4 shown in the figure handles each bit string information by converting it into cells. Cellization of bit string information is performed by cell matching processing units 5-1 to 5-7.

FIG. 4 shows the operation of the cell matching processing section 5-1. The cell matching processing unit 5-1 includes a video controller 1 for the STM7M switching network.
encoded video information is input at a speed of 54 kbps.

In response to this bit string input, the cell matching processing unit 5-1 collects, for example, 48 bytes of input into one cell, and
Output in bps. However, to simplify the explanation, the number of bytes of the cell header is omitted.

Other cell matching processing units 5-2 to 5-7 also output bit string inputs in units of cells, similarly to the cell matching processing unit 5-1.

FIG. 5 shows the multiplexing operation of cell information.

The encoded video information from the STM7M switching network video controller 1.1-2 is collected in cell units and sent to each FI.
Written to FO buffer 6-1.6-2. At this time, the video Kobuk 1 for the STM7M switching network (i4kbps
However, since the STM7M switching network video Kobuk 2 generates information at twice the speed, only one cell information is input to the FIF○ buffer 6-1 during the information generation interval T. In contrast, two pieces of cell information are input to the FIFO buffer 6-2.

Encoded video information from ATM switching network video controllers 2 to 2-3 and packet switching network data transfer device 3-
The packets from 1.3-2 are also grouped into cells and written to the FIF○ buffers 6-3 to 6-5, respectively.

Reading of cell information from the FIFO buffers 6-1 to 6-7 is performed by the control unit 10 sending read signals to the multiplex buses 8-1 to 8-3. The supply of read signals from the control unit 10 to the multiplexed bus is set in accordance with the number of accommodated devices and the information transmission speed so that encoded video information for the STM switching network is output within the period. . The supply of the read signal to the multiplex bus 8-2 is performed after the supply of the read signal to the multiplex bus 8-1 ends and until the read signal of the next cycle is supplied. Also,
The cell information output to the line during this cycle is monitored by the logic operation unit 9, and only when there is no AND output, that is, when there are no more cells to be sent to the line, the cell information is read out to the multiplex bus 8-3. supply the signal.

In this way, the coded video information for the STM switching network of 54 kbps that has been converted into cells is transmitted at the same interval T as the human power interval T.
is output to the line. The 128 kbps STM switching network encoded video information is output to the line two cells at a time during the same interval T.

FIG. 6 is a diagram showing the read operation of the multiplexed bus by the control unit 10, in which (a) shows the clock signal corresponding to the maximum number of cells that can be transmitted in the ATM switching network, (5), (C)
and (6) indicate read signals to multiplexed buses 8-1 to 8-3, respectively.

The control unit 10 transmits the readout signals shown in FIG. 6(b), (C), and Co., Ltd. to multiplexed buses 8-1 to 8-3 in synchronization with the clock signal shown in FIG. 6(a). supply to. In this embodiment, two STs of 54 kbps and 128 kbps are used.
Coded video information for M-switching network is mixed, but it is 54kb.
ps is used as the basic read signal, and 128 kbps read is not performed. For 128kbps information, 54
A transmission rate of 128 kbps is reproduced by combining two cells arriving at each kbps into a set.

The read signal output operation of the control section 10 will be explained in more detail.

The control unit 10 supplies three read signals to the multiplex bus 8-1 during the periodic interval T in order to send out the encoded video information for the STM switching network during the periodic interval T. (
Figure 6)).

Following this, the control unit 10 switches the supply of the read signal to the multiplexed bus 8-2 ((C) in the figure). While this readout signal is being supplied, the logic operation unit 9 monitors the availability of cell information to be output to the line.

When the logic operation section 9 detects empty cell information, the control section 1
0 multiplexes the supply of read signals at that point in the bus 8-
3 ((d) in the same figure). However, from the time when empty cell information is detected to the time when the readout signal is switched, the sixth
As indicated by T4 in the figure, the read signal may not be supplied to any of the multiplex buses 8-1 to 8-3 for several clocks.

When the periodic interval T ends, the control section 10 switches the supply of the readout signal to the multiplexed bus 8-1 again to maintain the periodic interval of the encoded video information for the STM switching network in the input and output.

Here, the periodic interval T of cell information will be explained. ST
The bit rate of encoded video information for M-switching network is 54kbps
, the cell information length is 48 bytes/cell, the cell cycle interval T is as follows. Therefore, the control unit 10 needs to supply the necessary number of read signals to the multiplex bus 8-1 every 5 ms.

Next, consider the case where the output is filled with cells of encoded video information for an STM switching network. Assuming that the transmission speed of the output side ATM switching network is 150 Mbps, the cell time interval when this is filled with cells of 48 bytes/cell is as follows.

Therefore, 6ms/2.5 JJs = 2400 units of 6
When connected to a 4kbps STM switching network video transmission network, it is not possible to transfer cells from other devices. Therefore, it is necessary to take into consideration the amount of information generated by each of the video data transfer devices for the STM switching network, the video data transfer device for the TM switching network, and the data transfer device for the packet switching network, and determine the number of units that each device can accommodate.

FIG. 7 is a diagram showing the operation of sending out a busy signal by the monitoring circuit 7-1.7-2.

The monitoring circuit 7-1 monitors the amount of cell information stored in the FIFO buffers 6-3 to 6-5, and when the amount exceeds the allowable amount, it sends a busy message requesting the information source to stop generating information or change the amount of information generated. Send a signal. The monitoring circuit 7-2 is an FI
The same operation is performed for FO buffers 6-6 and 6-7. As a result, the ATM exchange network video Kokutsuku 2-2
-3 and data transfer equipment for packet switching networks 3-1.3-2
It becomes possible to set the priority related to the transmission of generated information according to the intended use.

The notification method and timing of the busy signal will be explained with reference to FIG. 6. Here, as an example of boat fishing, we will use high priority FIFO 1 medium priority FIF ○ and low priority FIF
The case where O is monitored will be explained. The most important information is stored in the high priority FIFO, important information is stored in the medium priority FIFO, and general information is stored in the low priority FIFO. There is no need for each FIFO to be one.

When the storage capacity of the high-priority FIFO reaches a predetermined first value, the monitoring circuit sends a busy signal to the data transfer device connected to the low-priority FIFO, thereby increasing the information capacity of the line. ensure that If the amount of information stored in the high-priority FIFO still increases and reaches a predetermined second value, the monitoring circuit will cause the medium-priority FIFO to
Sends a device busy signal connected to the input of the FO.

When the high priority FIFO is filled with information, the supervisory circuit sends a busy signal to the device connected to that FIFO.

For the medium priority FIFO, when information has been accumulated up to the above-mentioned second value, a busy signal is sent to the device connected to the input of the low priority FIFO. When the medium priority FIFO is filled with information, it sends a busy signal to the device connected to the input of the FIFO.

In the case of a low priority FIFO, when it is filled with information, it sends out a busy signal to the devices connected to the FIFO's power.

However, the device connected to the FIFO manual is an ATM.
In the case of a switched network Tecodec, since the output information is video information, large delay fluctuations cannot be tolerated. Therefore, the total output information of each video controller is A on the output side.
It is necessary to predetermine the maximum amount of generated information for each video block so that it is close to the amount of information that can be transmitted on the TM line.

In addition, even if the output of each of the data transfer devices for the STM switching network, the video processing for the TM switching switching network, and the packet switching network is completed, there is still time until the transmission cycle of the video processing for the STM switching network. The line can be used more efficiently by performing processing such as retransmitting the video content for the ATM exchange network.

〔Effect of the invention〕

As explained above, the asynchronous multiplex transmission device of the present invention has the following features:
Information that requires periodic and real-time transmission, such as coded video transmission for STM switching networks, and aperiodic information that requires real-time transmission, such as coded video transmission for ATM switching networks. and non-periodic information that does not require real-time performance, such as packet information from a data transfer device for a packet-switched network, and multiplexed and transmitted while maintaining time transparency. This makes it possible to accommodate a plurality of devices that generate different types of information that could not previously be accommodated all at once, and to multiplex the information and connect it to the ATM network.

Furthermore, for non-periodic information, it is possible to set the priority related to information transmission, and when there is a congestion of information sent to the ATM line, each device can be assigned a priority according to the preset priority depending on the usage status of each device and other factors. It is possible to stop the information generation of the device or change the amount of information generation. Thereby, line usage efficiency can be further improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an asynchronous multiplex transmission apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a method for multiplexing encoded video information for an STM switching network. FIG. 3 is a diagram showing a method of multiplexing data for packet exchange. FIG. 4 is a diagram showing the cell matching processing operation. FIG. 5 is a diagram showing the multiplexing operation of cell information. FIG. 6 is a diagram showing the operation of reading and reading the multiplexed bus by the control unit. FIG. 7 is a diagram showing the operation of sending out a busy signal by the monitoring circuit. 1-1.1-2...Video control for STM exchange network-1 to 2-3...Video control for ATM exchange network-
1, 3-2... Data transfer device for packet switching network, 4
...ATM packet adapter, 5-1 to 5-7...
・Cell matching processing unit, 6-1 to 6-7... FIFO buffer, 7-1.7-2... Monitoring circuit, 8-1 to 8-3
. . . multiplexed bus, 9 . . . logical operation section, 10 . . . control section, 11 . . . line interface.

Claims (1)

[Claims] 1. Three types of information are multiplexed into an asynchronous switching network: periodic and real-time information, aperiodic and real-time information, and aperiodic and non-real-time information. The asynchronous multiplex transmission device that transmits the data includes cell forming means for forming each of the three types of information into cells, and a first output that temporarily stores and periodically outputs the cell-formed periodic and real-time information. a second output means for temporarily storing cellularized aperiodic real-time information and outputting it when the first outputting means does not output; a third output means that temporarily stores non-real time information and outputs it when there is no output from both the first output means and the second output means; the first output means; An asynchronous multiplex transmission apparatus comprising: multiplexing means for multiplexing the outputs of the second output means and the third output means.