JP2001077829A - Network data communication unit and network data communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit data in excess of capacity of a transmission data buffer of a device at a transmitter side to a receiver side device at a time in the case of sending/receiving data between devices connected to a network. SOLUTION: When a device D desires transfer of data to a receiver side device A and a capacity of a transmission buffer of its own device D is smaller than the data amount, a transmission reception buffer capacity detection means 143 detects a capacity of the transmission reception buffer of other device, a data transmission propriety discrimination means 142 decides a device (device for transmission proxy) B with a capacity of the transmission buffer by which desired transmission data can be sent at a time, a division data transmission means 147 divides the desired transmission data into a capacity less than that of the transmission buffer of its own device D and transmits the divided data to the proxy device B, and the proxy device B stores the divided data sent from the device D to its transmission buffer and transfers the data at a time t the receiver side device A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an I / O device capable of isochronous transmission of a plurality of signals to a plurality of devices.
The present invention relates to a network data communication device and a network data communication method suitable for an audio / video device or the like networked by an IEEE 1394 digital interface or the like.

[0002]

2. Description of the Related Art A parallel interface SCSI (Small) connecting a computer and peripheral devices, which has been the mainstream in the past, has been developed.
IEEE 1394 high-speed serial bus (IEEE is the Institute of Electrical and Electronics Engineers: The Institute of Electronics)
(Abbreviation of Electrical and Electronics Engineers, Inc., hereinafter referred to as IEEE 1394 or simply 1394)
Is attracting attention.

Prior to the formal standard, IEEE1394 was called P1394, and Nikkei Electronics 199
The details are described on pages 152 to 163 of the article (Reference 1) of 4.7.4 (No. 612), “Exploring post-SCSI design concept, comparing three new interfaces”. As described on page 161 and subsequent pages of the article, P1394 is based on computers,
"Isochronous for multimedia
It has a transfer function ", and is therefore more effective for image data than other interface methods. In other words, video and audio data must be
Every 5 μs), there is no jerkyness even if it is transferred and reproduced.

[0004] As described above, the IEEE 1394 is an isochronous transfer (also referred to as a synchronous transfer) that guarantees that data such as image data and audio data that require real-time performance are transferred at regular time intervals (125 µs). It has functions and is a serial interface suitable for multimedia applications. Data requiring real-time properties (referred to as real-time data) include MPEG2 transport stream (TS) packets used for digital broadcasting and the like, and digital video data (DV data) used for digital VCRs and the like. .

In IEEE 1394, a fixed period (125 μm)
A maximum of 64 data (packets) can be transmitted by time division multiplexing during s). Up to 63 nodes can be connected to one IEEE 1394 bus.

[0006] In addition to the synchronous transfer for transferring real-time data, the IEEE 1394 includes asynchronous transfer (asynchronous transfer) that guarantees that data is always transmitted to a destination device (node). IEEE13
The synchronous transfer of 94 operates based on a cycle of 125 μs (referred to as an isochronous cycle).
In each cycle, synchronous transfer is performed with priority given to image data or the like that requires real-time properties, and the remaining time is used for asynchronous transfer of commands and the like. The command indicates a control command such as a playback command or a stop command sent from one device to another device (for example, a VTR) when transferring image data or the like from device to device.

In order to transmit data (packets) from devices (nodes) connected to a network via an IEEE 1394 digital interface or the like, a link layer, a physical layer,
Send data through cable. Also equipment (node)
In order to receive the data, the data is received through the cable, the physical layer, and the link layer.

[0008] IEEE 1394 is described in detail in Japanese Patent Application No. 7-81548, Japanese Patent Application No. 8-309656, and Japanese Patent Application No. 7-342842.

When data is transmitted and received between devices (nodes) connected to a network via an IEEE 1394 digital interface or the like, synchronous transfer data such as image data (hereinafter simply referred to as synchronous data) is continuously transmitted at regular intervals. Asynchronous transfer data such as a command (hereinafter simply referred to as asynchronous data) is multiplexed and transmitted in a gap between synchronous data when necessary. That is, command data and the like are not normally transmitted continuously. In the case of control data such as a command among asynchronous data, data of a predetermined size is transmitted from the transmitting device to the receiving device at a time, and a predetermined operation is performed on the receiving device. Need to be ordered.

[0010] On the other hand, a transmission / reception buffer for synchronous data and a transmission / reception buffer for asynchronous data are separately provided in a link layer in each device on the transmission side and the reception side. Usually, a buffer for synchronous data such as image data is large, and a buffer for asynchronous data such as commands often has a relatively small capacity.

[0011] For example, regarding reception, serial data input into each device on the receiving side is divided into synchronous data such as image data and asynchronous data such as commands at the physical layer in each device on the receiving side. Then, the data is temporarily stored in a reception buffer for synchronous data and a reception buffer for asynchronous data in a link layer in the device.

As described above, asynchronous data such as a command is transmitted from the transmitting device to the receiving device as necessary, and the transmission / reception buffer for asynchronous data has a relatively small capacity. Is used, the following problem may occur in the asynchronous data transmission / reception buffer.

That is, when data is transmitted and received between devices (nodes) connected to a network via an IEEE 1394 digital interface or the like, even if the receiving buffer capacity of the receiving device is sufficiently large, the transmission device of the transmitting device does not. If the buffer capacity is small, data having a size exceeding the transmission buffer capacity of the transmitting device cannot be transmitted to the receiving device at one time.

For example, when the command data is data exceeding the transmission buffer capacity of the transmitting device, the transmitting device cannot transmit the control command to the receiving device at one time. This causes a problem that the device cannot perform an operation according to the control command.

[0015]

SUMMARY OF THE INVENTION As described above, the IEEE
When transmitting and receiving data between devices connected to a network via a 1394 digital interface or the like, if the receiving device has a sufficiently large receiving buffer capacity but the transmitting device has a small transmitting buffer capacity, Data having a size exceeding the transmission buffer capacity of the transmitting device cannot be transmitted to the receiving device at one time.

Accordingly, the present invention provides a method of transmitting and receiving data between a device connected to a network and transmitting data to the receiving device once, the data having a size exceeding the transmission data buffer capacity of the transmitting device. It is an object of the present invention to provide a network data communication device and a network data communication method capable of transmitting data to a network.

[0017]

A network data communication apparatus according to the present invention includes means for detecting the capacity of a transmission / reception buffer of another device connected to a network, and transmitting desired transmission data at one time from the detected capacity. Means for determining a device having a transmission buffer capacity capable of transmitting data, and means for dividing the desired transmission data into a size equal to or smaller than the transmission buffer capacity of the device and transmitting the determined transmission data to the determined device. is there.

In the present invention, when a certain device wants to transfer data to another device on the receiving side, and the transmission buffer capacity of the own device is smaller than the data capacity to be transferred, the data to be transferred is received. A device having a transmission buffer capacity that can be sent to the device at one time (a device that can perform transmission proxy) is found, and the desired transmission data is divided into a size smaller than the transmission buffer capacity of the device itself for this proxy device. This allows the proxy device to store the data divided and transmitted in the transmission buffer and then transfer the data to the receiving device at one time.

[0019]

Embodiments of the present invention will be described with reference to the drawings. 1 to 4 illustrate a network data communication device according to an embodiment of the present invention. Before describing an embodiment of the present invention, a method of transmitting and receiving data between devices connected to a network via an IEEE 1394 digital interface will be described first with reference to FIGS. Japanese Patent Application No. 7-81548
No.).

FIGS. 5 and 6 are explanatory diagrams for explaining the IEEE 1394 digital interface system capable of multiplex transfer of synchronous transfer and asynchronous transfer.

In IEEE 1394, 1 of Document 1
As described on page 62 and thereafter, multi-channeling is possible. FIG. 6 shows an example in which data of two channels of channels 1 and 2 (CH1, 2) is transmitted using a bus corresponding to IEEE 1394 (hereinafter referred to as a 1394 bus). IEEE 1394 is Daisy
Chain and tree topologies can be employed. FIG. 5 shows a plurality of devices A to D connected by a 1394 bus 13.
The figure shows an example of connection in a daisy chain via a 94 cable 40. The devices A to D are, for example, digital VTRs.

FIG. 6 shows an example of transmitting data from the device A to the device C and transmitting data from the device B to the device D. For example, the dubbing output from device A is
, And the dubbing output from the device B is dubbed and recorded in the device D.
In IEEE 1394, data is transferred in isochronous cycles every 125 μs.

FIG. 6A shows a video stream of dubbing output from the device A. This dubbing output is transferred every isochronous cycle. FIG.
(C) shows a video stream of dubbing output from the device B. This dubbing output is also transferred every isochronous cycle. A plurality of channels are allocated to the isochronous cycle, and a channel number indicating which channel is to be transferred is inserted in the packets output by the devices A and B. FIG. 6E shows that the output packet of the device A is transmitted on the channel 1 (ch1) and the output packet of the device B is transmitted on the channel 2 (ch2).

The devices A and B are respectively shown in FIG.
The command shown in (d) is output via the 1394 cable 40. These video streams and commands are
As shown in FIG. 6E, the data is multiplexed for each isochronous cycle and transferred by the 1394 cable 40. As shown in FIG. 6E, asynchronous data such as a command is multiplexed and transmitted in a gap between synchronous data (image data).

On the other hand, devices C and D are 1394 cables 40
From the channel number in the packet transmitted via
The transfer data to be received is determined, and the transfer data is received. That is, the device C receives the transfer data of ch1, and the device D receives the transfer data of ch2.

Next, the schematic configuration of each device (for example, device D) connected to the network as shown in FIG. 5 by the IEEE 1394 digital interface will be described with reference to FIG.

In FIG. 7, the input / output port 10a of the device 10 is connected to another device via the 1394 cable 40. Inside the device 10, a 1394 physical layer 1 for processing an electric signal input / output connected to the input / output port 10a
1 and the 1394 link layer 12 is connected to the physical layer 11. The 1394 link layer 12 includes a transmission / reception buffer (transmission buffer 121 and reception buffer 122) for synchronous data and a transmission / reception buffer (transmission buffer 123 and reception buffer 124) for asynchronous data. 13
An image data processing unit 13 and an arithmetic processing unit 14 are connected to the 94 link layer 12, and the image data processing unit 13 can exchange synchronous data with the synchronous data transmission / reception buffers (121, 122). The recording / reproducing process of synchronous data such as image data is performed on a recording medium (for example, a magnetic tape) not shown. The arithmetic processing unit 14 can exchange asynchronous data with the asynchronous data transmission / reception buffer (123, 124), encode and decode asynchronous data such as commands, and control the image data processing unit 13. I do. A command can be input to the arithmetic processing unit 14 from an instruction device 15 such as a remote control transmitter.

At the time of transmission, image data reproduced from a recording medium (not shown) is transmitted to the 1394 link layer 12 by the image data processing unit 13 after being processed for transmission, and temporarily stored in the synchronous data transmission buffer 121. After being stored, it is read out to the physical layer 11. On the other hand, the command data based on the instruction from the instruction device 15 is encoded by the arithmetic processing unit 14 and sent to the 1394 link layer 12, temporarily stored in the asynchronous data transmission buffer 123, and then stored in the physical layer 11.
Is read out. In the 1394 physical layer 11, the link layer 1
2, and multiplexes synchronous data such as image data and asynchronous data such as commands, and outputs them to the 1394 cable 40 as serial data.

At the time of reception, serial data in which synchronous data and asynchronous data of a plurality of channels transmitted via the 1394 cable 40 are multiplexed enters the 1394 physical layer 11, where the serial data is asynchronous with the synchronous data. And the synchronization data is distributed to the link layer 12.
After being temporarily stored in the synchronous data reception buffer 122, the data is sent to the image data processing unit 13 to perform data processing for recording and recording processing on a recording medium (for example, a magnetic tape) (not shown). Asynchronous data divided by the physical layer 11 is received in an asynchronous data reception buffer in the link layer 12.
After being temporarily stored in 124, the data is sent to the arithmetic processing unit 14 to decode asynchronous data such as commands and control the recording / reproducing operation in the image processing unit 13.

Next, an embodiment of the present invention will be described with reference to FIGS.
The transmission and reception data handled here is,
In the IEEE 1394 digital interface, data of a predetermined size is transmitted at a time and received by the target receiving device at one time, so that data corresponding to a protocol for causing the target receiving device to perform a desired operation,
For example, it is asynchronous data such as a command.

Here, in order to clarify the difference from the prior art, a conventional network data transmission method will be described with reference to FIG.

Now, as shown in FIG. 4, it is assumed that five devices from device A to device E are connected to the network via an interface. In this specification, a case in which an IEEE 1394 digital interface is used as an interface will be described.

In the state as shown in FIG. 4, for example, consider a case where data of 400 bytes is transmitted from device D to device A. In this case, since the size of the transmission buffer of the transmitting device D is only 256 bytes, the receiving device A
Has a 512-byte receive buffer,
It is impossible to transmit byte-sized data to the device A at one time.

For example, in the IEEE 1394 digital interface, there is a protocol for transmitting data of a predetermined size at one time and causing the receiving device to receive the data at one time, thereby causing the receiving device to perform a desired operation.
In order for device D to perform a desired operation on device A using this protocol, 400 bytes of data are
If it is necessary to perform reception, the problem of the transmission buffer capacity becomes a bottleneck, and a desired operation cannot be realized. Therefore, the present invention is to realize a network data communication device equipped with means for solving such a problem.

FIG. 1 shows a configuration of a network data communication apparatus according to an embodiment of the present invention. FIG. 1 shows functional blocks as a transmitting device. FIG. 1 shows only a control part necessary for a process of finding a device capable of performing transmission and transmitting the same to a receiving device when transmitting asynchronous data such as a command, that is, only a necessary control part in the arithmetic processing unit of FIG. Is shown as a block diagram.

The network data communication device 10 shown in FIG.
0 is the 1394 physical layer connected to the 1394 cable 40
110, a transmission buffer 123 for asynchronous data, and a reception buffer 124, and these transmission / reception buffers (123, 124)
A 1394 link layer 120 for acquiring information about another device or transmitting asynchronous data to the other device, and a portion including characteristic components according to the present invention. Based on the information received from the other device, the capacity of the transmission / reception buffer of the other device is detected, a device having a transmission buffer capacity equal to or larger than the amount of asynchronous data to be transmitted is determined, and transmission to this device is performed. An arithmetic processing unit 140 which divides the asynchronous data to be transmitted into a size smaller than the transmission buffer capacity of the own device and transmits the divided data, a memory 160 having at least the own device information area, and an instruction device 150 capable of inputting a command. It is configured. The arithmetic processing unit 140 can be constituted by a microcomputer.

The configuration of the communication device 100 is a transmission / reception circuit for asynchronous data of the device 10 described with reference to FIG.
94 physical layer 11 and asynchronous data transmission / reception buffer 12
A 1394 link layer 12 including at least 3 and 124; an arithmetic processing unit 14 capable of encoding or decoding asynchronous data such as commands input / output to / from the asynchronous data transmission / reception buffers 123 and 124; The transmitting / receiving circuit for synchronous data such as the image data shown in FIG.
Parts corresponding to (12, 121, 122, 13) are omitted.

Hereinafter, each component will be described with reference to FIG. The operation instruction (command) input by the instruction device 150 is detected by the instruction detecting means 141. The pointing device 150 may be an operation panel provided on the device main body, or may be a remote operation means such as a remote control transmitter. The instruction detecting means 141 may be constituted by a dedicated microcomputer. The instruction detecting unit 141 analyzes the content of the instruction and generates transmission data that must be transmitted to a target receiving-side device in order to realize the specified operation.

Hereinafter, description will be given along three major processes i), ii) and iii). i) The data transmission availability determination means 142 includes the instruction detection means 141
Then, the size of the generated transmission data is compared with the capacity of the transmission buffer 123 of the own device which is written in the own device information area 161 of the memory 160 of the own device.

FIG. 2 shows an example of the description of the transmission buffer capacity in the memory 160 of the own device and the own device information area 161.
For example, the capacity of the transmission buffer 123 of the own device is 256 bytes, the capacity of the reception buffer 124 is also 256 bytes, and the work area (the area used for processing asynchronous data received when the present apparatus functions as a receiving apparatus). ) Has a capacity of 800 bytes.

When the size of the transmission data is smaller than the transmission buffer capacity as a result of the comparison by the data transmission availability determination means 142, the desired transmission data can be transmitted from the own device at one time. It is possible to perform transmission and cause a receiving-side device to perform a desired operation.

If the size of the transmission data is larger than the transmission buffer capacity and the data cannot be transmitted from the own device at once as a result of the comparison by the data transmission availability determination means 142, the following processing is performed. Do.

Ii) Transmission / reception buffer capacity detection means
143, the memory space of each device connected to the network (the device information area 161 of the memory 160 of the device itself).
By reading the transmission / reception buffer capacity of each device, the capacity of the transmission / reception buffer of another device is detected. The description example of the transmission / reception buffer capacity stored in the memory space (own device information area) of each device is the same as that in FIG. FIG. 2 shows an example in which the transmission and reception buffer capacities are each 256 bytes, but the transmission and reception buffer capacities of other devices are each doubled to 5 times.
It may be 12 bytes.

The data transmission availability judging means 142 includes a transmission buffer capacity of another device detected by the transmission / reception buffer capacity detection means 143 and a desired transmission data generated by the instruction detection means 141 based on the instruction of the instruction device 150. Compare with the size of. As a result of the comparison by the data transmission availability determination means 142, if the transmission buffer capacity detected from another device is larger, the device name is stored in the data transmission possible device storage unit 144 as device data. FIG. 3 shows a storage example of the data-transmittable device storage unit 144. FIG. 3 shows another device having a transmission buffer capacity capable of transmitting desired transmission data generated by the own device to the intended receiving device A at a time when the own device is set to D (a device capable of acting for transmission). (Device B, device E,...) Are shown.

The processing for detecting the transmission / reception buffer capacity and determining whether to transmit data for the other devices is performed for all devices connected to the network except for the transmitting device and the receiving device.

For example, as to five devices A to E connected to a network as shown in FIG. 4, when transmission data is transmitted from device D to device A, the user wants device A to perform a desired operation. The transmission / reception buffer capacity detection and detection are performed for the devices B, C, and E, excluding the device D as the transmitting device and the device A as the receiving device, from among the five devices connected to the network. The data transmission availability determination process is performed.

Iii) Next, the data transmission device storage unit 1
The size of the work area of the target device is detected by the work area capacity detecting means 145 for all the data transmittable devices stored in FIG. 44 as shown in FIG. The detection of the work area capacity is performed by reading the work area capacity described as shown in FIG. 2 in the memory space (own apparatus information area) of each device.

The work area capacity determination means 146 compares the size of the work area detected for each device with the size of desired transmission data. Work area capacity determination means 146
As a result of the comparison, if the detected work area is smaller, it is determined that the transmission data cannot be fetched, and the data (device name) relating to the device is stored from the data transmittable device storage unit 144. to erase.

For example, if the data transmission permission / inhibition determination processing is performed on the device E, and it is found that the work area capacity is not enough for the size of the transmission data, the data transmission shown in FIG. The storage information of the device E is deleted from the list of possible devices.

After that, the divided data transmission means 147 transmits the desired transmission data to one of the plurality of devices (for example, device B) which can perform transmission among the plurality of devices stored in the data transmission possible device storage section 144. Divide and send the data.
The desired transmission data is divided by the divided data transmission means 147 into an appropriate size equal to or smaller than the transmission buffer capacity of the transmitting device D and transmitted.

For example, as shown in FIG. 4, when the size of the transmission data is 400 bytes and the capacity of the transmission buffer 123 of the transmitting device D is 256 bytes, the transmission data is 200 bytes in size. It is divided into two and transmitted twice. The data-transmittable device B that has received the divided-transmitted data combines the transmitted divided data on the work area by its own divided-data combining unit. At this stage, desired transmission data is constructed on the work area of the data transmission enabled device B.

If the device B capable of data transmission described above combines the data divided and transmitted for the reason that it does not have the divided data coupling means, and the desired transmission data cannot be constructed on the work area, the data transmission is possible. Device storage unit 144
The above-mentioned divided data transmission process is performed for another device (for example, device C) stored in the.

As described above, even if the desired transmission data is larger than the transmission buffer capacity of the transmitting device itself, the transmission buffer capacity and the working area capacity of other devices connected to the network are checked. A device that can transmit data (device B or device C) is found, divided transmission is performed on the device that can transmit data, and the data is reconstructed (combined). From device B or device C) to device A on the receiving side
Can be transmitted at one time, and as a result, the transmitting device D
Can perform a desired operation by transmitting data to the receiving-side device A at a time.

In the above-described embodiment, the digital interface of the IEEE 1394 system has been described as an interface. However, the present invention is not limited to this, and other digital interfaces such as a USB (Univ.
ersal Serial Bus).

Further, the present invention can be widely applied to a communication method of a protocol which requires that data of a certain size be transmitted at one time and received by a receiving device at one time.

[0056]

As described above, according to the present invention, when data is transmitted and received between devices connected to the network, the desired transmission data is larger than the transmission buffer capacity of the transmitting device. Also, there is an effect that a device capable of performing transmission can be selected from the network and transmitted to the device on the receiving side at once.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a network data communication device according to an embodiment of the present invention.

FIG. 2 is a view showing an example of description of own device information in a memory space of the own device.

FIG. 3 is a diagram showing a storage example of a data transmission enabled device storage unit.

FIG. 4 is an exemplary view for explaining a transmission process by the network data communication device in FIG. 1;

FIG. 5 is an explanatory diagram for explaining an IEEE 1394 interface system;

FIG. 6 is an explanatory diagram for explaining an IEEE 1394 interface system.

FIG. 7 is a block diagram showing a schematic configuration of a device connected to a network as shown in FIG. 5;

[Explanation of symbols]

123: transmission buffer, 124: reception buffer, 141
... Instruction detection means (transmission data generation means), 142 ... Data transmission availability determination means, 143 ... Transmission / reception buffer capacity detection means, 144 ... Data transmission enabled equipment storage section, 145 ... Work area capacity detection means, 146 ... Work area Capacity determination means, 147 divided data transmission means, 150 instruction device (command input means), 160 memory, 161 own device information area, 162 work area.

Claims (6)

[Claims] A means for detecting the capacity of a transmission / reception buffer of another device connected to the network; a means for determining a device having a transmission buffer capacity capable of transmitting desired transmission data at one time from the detected capacity; A network data communication apparatus, comprising: means for dividing desired transmission data into a size smaller than the transmission buffer capacity of the own device and transmitting the transmission data to the determined device. 2. A means for detecting the capacity of a transmission / reception buffer of another device connected to the network, wherein the information described in a memory space of another device, which is readable and writable by a device in the network, is 2. The network data communication device according to claim 1, wherein the network data communication device is a detecting unit. 3. A means for detecting a capacity of a work area mounted on a device having a transmission buffer capable of transmitting desired transmission data at a time, wherein said capacity is necessary for combining divided data. 2. The network data communication device according to claim 1, further comprising means for determining that the capacity is larger than the capacity of the work area. 4. A means for detecting the capacity of a work area mounted on a device having a transmission buffer capable of transmitting desired transmission data at a time, comprising: 4. The network data communication device according to claim 3, wherein the network data communication device is means for detecting information described in a memory space. 5. A step of detecting a capacity of a transmission / reception buffer of another device connected to a network; and a step of determining a device having a transmission buffer capacity capable of transmitting desired transmission data at one time from the detected capacity. A step of dividing desired transmission data into a size smaller than the transmission buffer capacity of the device and transmitting the transmission data to the determined device. 6. A step of detecting a capacity of a work area mounted on a device having a transmission buffer capable of transmitting desired transmission data at a time, wherein said capacity is necessary for combining divided data. 6. The network data communication method according to claim 5, further comprising the step of determining that the capacity is larger than the capacity of the work area.