JP2002152198A - Method and device for multicast transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicast transfer device which send a large amount of data by multicast transfer from one device to other devices at a high speed through an asynchronous communication system. SOLUTION: A task table generation part 115 generates task parameters, each composed of a Destination ID, a Segment buffer offset, a Max Payload, and Data length, by receiving devices and rearranges the generated task parameters in order to generate a task table. A transfer actuation part 113 places a firmware part 11 in a state wherein DMA transfer is carried out and a data transfer control part 125, a task table control part 126, and a DMA control part 122 are actuated; and the data transfer control part 125 switches devices as data distribution destinations in a short time so as to perform real- time data transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data transfer technique for performing multicast transfer in an asynchronous communication system.

[0002]

2. Description of the Related Art IEEE 1394 has attracted attention as a general-purpose interface for connecting a personal computer, its peripheral devices, a digital TV, and the like. IEEE 1394
Is a serial interface capable of high-speed transfer of 100 Mbit / s to 400 Mbit / s, employs isochronous transfer capable of guaranteeing a transfer band, and is a promising candidate for a next-generation multimedia interface.

[0003] It is an upper protocol of IEEE1394.
Asynchronous Serial Bus Connection protocol includes
Multicast transfer for performing data communication from one transmitting device to a plurality of receiving devices with the same data in consideration of real-time performance is specified, but no specific method of realizing the multicast transfer is described.

[0004]

A plurality of devices are connected,
There is a demand for transferring large-capacity data from one device to a plurality of other devices at high speed. As an example,
Connect digital broadcast receivers, digital TVs, personal computers, and peripheral devices such as hard disk drives, receive digital video data with the digital broadcast receivers, convert the received digital video data to digital TV, and display it. However, there is a demand for recording the digital video data in real time on a hard disk device inside a personal computer.

[0005] In order to fulfill the above needs, the present invention provides:
It is an object of the present invention to provide a multicast transfer device and a multicast transfer method for performing high-speed multicast transfer of a large amount of data from one device to a plurality of other devices in an asynchronous communication method.

[0006]

In order to achieve the above object, the present invention is directed to a multicast transfer apparatus for transferring one transfer data in real time to a plurality of connected receiving apparatuses by an asynchronous transfer method. Transfer data storage means for storing one piece of transfer data; information acquisition means for acquiring, from a plurality of connected reception apparatuses, apparatus information relating to each of the reception apparatuses; An information storage means for storing the transfer data, and a data transfer means for transmitting the transfer data to each of the receiving apparatuses while switching the receiving apparatus to which the transfer data is to be transferred, in accordance with each apparatus information stored in the information storage means. It is characterized by having.

Here, the data transfer means may be configured to switch the receiving device to which the transfer data is transferred so that each receiving device can receive the transfer data within a predetermined time zone. Here, the data transfer means may be configured to switch the receiving device to which the transfer data is transferred so that the time required to transfer the transfer data to each receiving device is equal.

Here, the data transfer means may be configured to switch the receiving device to which the transfer data is transferred so that the amount of data to be transferred to each receiving device is equal. Here, the multicast transfer device performs data transfer using any one of a plurality of communication protocols, and further includes a selection unit that selects one of the plurality of communication protocols. The plurality of communication protocols have a common data format, the information acquisition unit acquires device information having a common data format, and the information storage unit stores device information having a common data format. The data transfer means may be configured to transmit the transfer data to each receiving device according to a selected communication protocol.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment according to the present invention, a data transfer system 5 for performing Asynchronous Serial Bus Connection multicast transfer will be described. (Data Transfer System 5) As shown in FIG. 1, the data transfer system 5 includes a VTR playback device 1 as a transmitting device as a data supply source, a digital TV device 2 as a receiving device as a data supply destination, and a personal computer. A VTR playback device 1 and a digital T
V device 2 connected by bus B1 and digital TV device 2
And the personal computer 3 are connected by a bus B2. Such a connection form is called a daisy chain.

[0010] Asynchronous Serial Bus Connection is
This is a protocol for transmitting and receiving data using the asynchronous transfer method of IEEE1394, but data transfer considering real-time properties is required. The VTR playback device 1 converts analog video data composed of analog signals into digital video signal data in a format specified by MPEG, and converts the digital video signal data and OSD (On Screen).
OSD data to be displayed on the display is transmitted to the digital TV device 2 and the personal computer 3 in real time, and the digital TV device 2 receives and displays the digital video signal data and the OSD data. Digital video signal data and OS
D data is received and stored internally.

The VTR reproducing apparatus 1 transmits digital video signal data by isochronous transfer, and transmits the OSD data to Asynchronous transfer.
Send by Asynchronous transfer using chronous Connection. Here, real time means that the transmitting device sequentially transmits a part of the transfer data to each of the plurality of receiving devices within a predetermined short time.

The digital TV device 2 is an MPEG2 unit 2
1, display unit 22, LSI unit 23, hard disk unit 24
The LSI unit 23 is connected via a 1394 bus B1 to
It is connected to the LSI unit 12 of the VTR playback device 1 and
LSI of the personal computer 3 via the bus B2
It is connected to the unit 12. The LSI unit 23 receives digital video signal data and OSD data in real time, the MPEG2 unit 21 generates analog video signal data from the digital video signal data, and the display unit 22 displays analog video signal data and OSD data. Is displayed. The hard disk unit 24 stores digital video signal data and OSD data. The LSI unit 23 includes an LSI
It is the same as the part 12.

The personal computer 3 has an internal bus 3
1, microprocessor 32, video data storage unit 33,
OSD data storage unit 34, display unit 35 and LSI unit 36
The LSI unit 36 includes digital video signal data and O
The SD data is received in real time, the OSD data storage section stores the OSD data, and the video data storage section 33 stores the digital video signal data. (VTR playback device 1) As shown in FIG. 1, the VTR playback device 1 includes an application unit 10, a firmware unit 1
1, an LSI section 12, an OSD data storage section 13, a task table storage section 127, an MPEG2 section 15, and an analog video data storage section 16. (OSD Data Storage Unit 13, MPEG2 Unit 15, and Analog Video Data Storage Unit 16) The analog video data storage unit 16 records analog video data from analog signals and analog audio data composed of analog signals in advance. An example of analog video data and analog audio data is video and song accompaniment music used in a karaoke performance device (karaoke means an orchestra without a song).

The OSD data storage section 13 stores OSD data to be superimposed and displayed on video data. One example of OSD data is lyrics data composed of a character string used in the karaoke performance device. When the accompaniment music of the video and the song is played, the lyrics data is displayed on the display unit in accordance with the playback, and the user can sing along with the played back accompaniment music while watching the displayed lyrics. Sing

The MPEG2 unit 15 reads the analog video data stored in the analog video data storage unit 16, converts the read analog video data according to MPEG2, generates digital video data, and generates the generated digital video data. Is output. MPEG2 is well known and will not be described. (Application section 10, firmware section 11, L
The SI unit 12 and the task table storage unit 127) The firmware unit 11, as shown in FIG.
1. The communication control parameter generation unit 114, the task table generation unit 115, and the transfer path unit 113
The I unit 12 includes a DMA control unit 122, a transfer trajectory parameter setting unit 123, a task table setting unit 124, a data transfer control unit 125, a task table generation unit 126, and a task table storage unit 127.

The application section 10 outputs a data transmission instruction to the firmware section 11. The firmware unit 11 receives a data transmission instruction from the application 10. Upon receiving the data transmission instruction, the task management unit 111 is activated. (Setting of Task Table) When started, the task management unit 111 starts a transfer process. When the transfer process is started, the communication control parameter generation unit 114 is activated, and the communication control parameter generation unit 114 generates and generates the total number of receiving devices for which a connection has been established and the number of transaction retries (Max retry). The transfer start parameter setting unit 123 is notified of the total number of the receiving devices and the transaction retry count.

The transfer start parameter setting unit 123 receives the parameters generated by the communication control parameter generation unit 114, and transmits the received parameters to the LSI unit 12
Set to a predetermined register inside. When the setting of the communication control parameters is completed, the control is transferred from the transfer start parameter setting unit 123 to the task table generation unit 115.

[0018] The task table generating unit 115 is
ion ID, Segment buffer offset, Max Payload,
A task parameter including the data length is generated for each receiving device. Here, Destination ID is an identifier for uniquely identifying each receiving device, and is a segment ID.
The buffer offset is an IEEE that each receiving device has and represents the head of a segment buffer for saving received data.
1394 logical address, MaxPayload is the maximum data length that the transmitting device can transfer in one transaction, and Data length is the number of bytes of the total data transmitted by the transmitting device to each receiving device. This is obtained from the application unit 10 via a global variable.

Next, the task table generation unit 115 generates a task table by arranging the task parameters generated for each receiving device in order. FIG. 3 shows an example of the task table. In this figure, the task table 220
Task parameters 221, 231, 241, 251,.
・ ・ Consists of The task parameter 221 is Dest
ination ID 211 and Segment buffer offset 212
, Max Payload 213, reserve area 214, Dat
a length 215. They are 16-bit length, 48-bit length, 16-bit length, 16-bit length, 32
Bit length. The total length of the task parameter 211 is
It is 128 bits. The reserve area 214 is 1
Includes six "0" bits.

Task parameters 221, 231, 24
1, 251,... Correspond to the respective receiving devices. In the present embodiment, since the receiving devices are the digital TV device 2 and the personal computer 3, the task parameters 22
1 and 231 are set, and the task parameters 221 and 231 are task parameters for the digital TV device 2 and the personal computer 3, respectively. Each task parameter is indicated by an array index.

Next, the task table generator 115 repeats the created task table in 32-bit units via a port register provided in the LSI unit 12 and outputs it to the task table setting unit 123. Task table setting unit 1
24 sequentially saves the task table written via the port register into the task table storage unit 127.

As described above, the introduction of the task table makes it possible for the LSI unit 12 to centrally manage information on devices to which data is distributed. (DMA transfer) When the setting of the task table is completed by the above operation, the control is transferred to the transfer start unit 113.
The transfer activation unit 113 shifts the firmware unit 11 to a state in which DMA transfer is being performed, and sends a DMA transfer activation signal to the LSI unit 12.

When a DMA transfer start signal is sent to the LSI unit 12, the data transfer control unit 12
5, task table control unit 126, and DMA control unit 122
Is started. The data transfer control unit 125 includes means for switching a device to which data is distributed in a short time in order to perform real-time data transfer. In the embodiment of the data transfer method according to the present invention, the IEEE 1394 packet is transmitted to the bus. A method of switching the transmission destination device every time transmission is performed is used.

The data transfer control unit 125, as shown in FIG. 4, has an XFER_START_CHE composed of 16 transmission permission flags.
It has a CK register 251 and an XFER_END_CHECK register 252 composed of 16 transfer completion determination flags. Each flag is 1 bit long. Each of the 16 transmission permission flags corresponds to 16 receiving devices, and the 16 transfer completion determination flags correspond to 16 receiving devices. In this embodiment, two receiving devices (digital T
Since the V device 2 and the personal computer 3) are connected to the transmission device (VTR playback device 1), the first transmission permission flag and the first transfer completion determination flag correspond to the digital TV device 2, The second transmission permission flag and the second transfer completion determination flag correspond to the personal computer 3. The third to sixteenth transmission permission flags and the third to sixteenth transfer completion determination flags are not used.

The processing flow of the data transfer control unit 125 will be described with reference to the flowchart shown in FIG. When the transfer is activated, the data transfer control unit 125
The number of receiving devices is obtained by calculating the number of task parameters registered in the task table stored in the task table storage unit 127 incorporated in the SI unit 12 (step S100), and the XFER_END_CHECK register 252
XFER_START_CHECK register 251 consisting of 16 transmission permission flags
XFER_START
Among the flags of the _CHECK register 251, a value of 1 is set to a flag corresponding to a receivable receiving device (step S101).

Next, for each of the receiving devices, a device whose transmission permission flag is 1 and whose transfer completion determination flag is 0 is selected. In other words, a receiving device that can receive data and that has not completed transfer is selected, and an array index indicating a task parameter corresponding to the selected receiving device in the task table is notified to the task table control unit 126 (step S102).

Next, the task table control unit 126
A signal indicating packet transmission is sent to the MA control unit 122, and D
The MA control unit 122 determines the Dest of the receiving device included in the task parameter indicated by the notified array index.
ination ID, Max Payload, Segment buffer offset
Is used to create a header area for the IEEE1394 transmission packet. Next, determine the length of the data to be added so that the value obtained by adding Max Payload to the Segment buffer offset does not become larger than the end address of the segment buffer,
Data corresponding to the determined data length to be added is acquired from the transmission data buffer 13, a data packet is added to the header section to create a transmission packet, and transmitted on the IEEE1394 bus (step S103).

Next, the DMA control unit 122 notifies the task table control unit 126 of the authentication (Ack) code for the transmission packet, and the task table control unit 126 checks that the notified authentication (Ack) code is not an error. For example, Segment
The buffer offset is increased by the transmission data. If the updated Segment buffer offset matches the end address of the segment buffer, set Segment buffer off.
Set is updated to the start address of the segment buffer, and Dat
The task table is updated so that the transmitted data length is subtracted from a length (step S104).

Next, the data transfer control unit 125 checks whether the Data length updated by the above operation is 0, and if the Data length is 0 (step S10).
5) The transfer completion determination flag corresponding to the receiving device that has transferred the data is set to 1 (step S107). If the transfer completion determination flag is 1 (step S111), an end notification is output to the receiving device (step S112). It is checked whether or not the transfer completion determination flag corresponding to the other receiving device is set to 1, and if the transfer has been completed for all the receiving devices (step S108), the transfer completion interrupt is determined. Notify the firmware 11.

If the data transfer to all the receiving devices is not completed (step S108), the array index of the receiving device that has not been completed is notified to the data transfer control unit 125, and the process returns to step S102 to repeat the process. . If the data length is not 0 in step S105, it is determined whether to change the data transmission destination to another receiving device. If the transmission destination is not changed (step S10).
6) Return to step S103 and repeat the above processing.

When the transmission destination is to be changed (step S106), the process returns to step S102, shifts the control to the data transfer control unit 125, and repeats the above processing. next,
Details of the data packet transmission processing shown in step S103 will be described with reference to the flowchart shown in FIG. The DMA control unit 122 acquires the size of the segment buffer from the Segment buffer size (step S2).
00). Here, the segment buffer size is the segment buffer size of the receiving device notified from each receiving device (digital TV device and personal computer) before transfer. Next, the DMA control unit 122
The length of the data to be added to the transmission packet is determined from the oad (step S201), and the length of the data is determined from the segment buffer offset.
Set the stination offset field (step S2
02). Here, the Destination offset field contains the next write instruction (specifically, Write Request
st issuance) is shown. The Segment buffer offset is incremented each time a write transaction succeeds. When the transfer is started, the value is incremented in the hardware every time a transfer process is performed. Therefore, the start (logical) address of the segment buffer is set in the Destination offset before the transfer is started.

Next, when the Segment Buffer offset is Max Pa
If it is larger than yload + Destination offset (step S203), the data length to be added to the transmission packet is set (step S204), the destination ID field of the transmission packet is set from the destination ID (step S205), and the data is stored in the OSD data storage unit 13. lengt
The transmission data for h is extracted and shaped into an IEEE 1394 packet (step S206), a data packet is output to the DMA circuit (step S207), and the DMA circuit sends the packet to the IEEE 1394 bus (step S208).

Next, the ACK is received, and the received ACK is received.
Indicates completion (step S209), the process ends. If not (step S209), step S
Returning to step 208, the sending process is repeated. Segment Buffer o
If ffset is smaller than or equal to Max Payload + Destination offset (step S203), control is transferred to step S107.

Next, the details of the process of updating the task table shown in step S104 will be described with reference to the flowchart shown in FIG. Task table control unit 126
Subtracts the transmitted data length from the Data length (step S300), and adds the transmitted data length to the Segment buffer offset to update the task table (step S301). (Summary) As described above, Asynchronous Serial Bus Co
When implementing multicast transfer in the nnection protocol, information about the receiving device is sent to the controller LSI.
Since the (LSI unit) collectively manages data, it is not necessary to activate firmware for switching operation of the data receiving device, and data can be transferred to a plurality of devices at high speed.

The provision of the means for controlling the switching of the data receiving devices in units of transmission packets makes it possible to reduce the time required from the start of data transfer to the switching operation of the data distribution destination. The transmission order of data packets can be controlled in units of packets by the controller LSI that generates and transmits data packets managing the information of the receiving device. In addition, by providing a function of switching a packet transmission destination in units of packets, it is possible to prevent data packets from being continuously transmitted to a specific receiving device, and to transfer data requiring real-time performance. It is effective for (Other Modifications) Although the present invention has been described based on the above embodiment, it is needless to say that the present invention is not limited to the above embodiment. The following cases are also included in the present invention. (1) In the embodiment of the data transfer method of the present invention, the data transfer control unit 125 uses a method of switching the data transmission destination each time one data packet is transmitted. Alternatively, the function of starting the timer may be provided in the task table generation unit 115, and the data transfer control unit 125 may be provided with the timer, so that the transmission destination may be switched by time management.

When the transfer control parameter generation unit 114 has a timer starting function, it can be realized by adding a register for setting a timer timeout value to the LSI unit 12 and setting the timeout value in the register.
In the case of the above method, the time allocated to each receiving device in one transfer is constant. When the task table generation unit 115 has a timer activation function, a new parameter area can be added to the task table 401, and the timeout value of the timer can be set arbitrarily for each receiving device. In the case of this method, it is possible to set the time from the start of data transmission to a specific receiving device until the switching process occurs for each receiving device. (2) A method may be adopted in which data is continuously transmitted until the data storage buffer of the receiving device is full, and when the data storage buffer is full, data is transmitted to the next receiving device.

When this switching method is used, when data is first transferred to the first receiving device, data is continuously transmitted until the segment buffer of the first receiving device is filled, and the segment buffer is filled with data. Then, a switching operation occurs, and data is transmitted to the second receiving device. The transfer to the second receiving device continues until the segment buffer of the second receiving device is filled with data.
The above operation is repeated to execute the multicast transfer. (3) In cooperation with the application 10, by adding a parameter indicating the data length to be continuously transmitted to one receiving device from the format of data to be transmitted to the one receiving device to the task table, the switching operation of the receiving device based on the transfer data length May be performed. (4) The embodiment according to the data transfer method of the present invention does not limit the number of receiving devices. Asynchronous Serial
It is effective including all connection construction numbers up to a maximum of 14 specified by the Bus Connection standard. In FIG.
The figure shows a case where two receiving devices establish a connection with one transmitting device. (5) SBP2 protocol and Asynchronous Serial Bus Co
When the nnection protocol is implemented in one LSI, the above embodiment may be applied.

FIG. 8 shows a state in which the transmission data 202 is taken into the data receiving device 30 in the data transfer method using the page table defined by the SBP2 protocol. FIG. 9 shows the data structure of the page table. As shown in FIG. 9, the page table is
It consists of Page size and Segment buffer Offset. Page size indicates the size of the data reception buffer, and Segment buffer Offset is the start address of the segment buffer of the receiving device for saving the received data.

In the page table transfer, when the receiving device 30 cannot secure an area for saving received data in a continuous space, a plurality of discontinuous memory spaces 301, 302, 30
3 is prepared, and the secured memory spaces 301 and 30 are prepared.
A page table 201 having the size and the start address of each of the data transmission devices 20 and 303 is created.
However, by reading the page table 201, data transfer to the discontinuous memory space is realized. Here, the transmission data 202 and the divided memory spaces 301 and 302,
The total of 303 becomes the same size.

In FIG. 8, by introducing a concept that each of the memory spaces 301, 302, and 303 secured in the discontinuous space is regarded as one receiving device, the multicast transfer can be performed in the same manner as in the above embodiment. realizable.
FIG. 9 shows a multicast transfer using the above concept.
The LSI unit 12 transfers the data 402 to each of the receiving devices 50, 60, and 70 by performing a transfer process according to the task table 220.

Segment, which is the buffer size of the receiving device
buffer size and P included in the page table shown in FIG.
The age size indicates the size of the data reception buffer, and the segment buffer offset included in the basic element of the task table shown in FIG. 3 and the Segment buffer size included in the basic element of the page table shown in FIG.
Both indicate the head address of the data receiving buffer. In the execution of data transfer using the data transfer method according to the present invention, the buffer management of the page table transfer control technique used in the SBP2 controller LSI 20 is the same. Circuits can be shared. In order to realize the data transfer method according to the present invention, the task table 220 is created by sequentially adding parameters that need to be newly introduced to the task table in addition to the buffer management parameters.

The above-described SBP2 and Asynchronous Serial Bus
When implementing the Connection protocol, the LSI unit 12
Introduces a register that controls which protocol is to be used. In the case of the present embodiment, since it is assumed that two protocols are implemented, an area for one bit may be secured. If 1 is set in the reserved register area, Asynchronous Serial Bus Connecti
In the case of on or 0, the controller LSI 12 is used in SBP2.

The switching of the protocol to be used is as follows.
It changes depending on the device on which the LSI 12 is mounted, and sets an operation mode when the power of the device is turned on. In the present embodiment, Asynchronous Serial
Although the case of BusConnection and SBP2 has been described, the present invention can be applied to other similar general protocols for controlling a plurality of transfer destinations, and does not limit the protocols to be implemented.

As described above, the SBP2 protocol and Asynchrono
When creating a controller LSI implementing the us Serial Bus Connection protocol, it is possible to share a hardware circuit used in each of the protocols. (6) Although FIG. 1 shows a daisy-chain type connection, the method of the present invention is effective for a configurable topology defined by IEEE1394.
Further, the data transfer method according to the embodiment of the present invention
This is effective for all devices existing on the topology constructed according to the EE1394 standard. (7) The present invention may be the method described above.
Further, these methods may be a computer program that is realized by a computer, or may be a digital signal formed by the computer program.

The present invention also relates to a computer-readable recording medium, such as a floppy (registered trademark) disk, hard disk, CD-ROM, MO, DVD, D
The information may be recorded on a VD-ROM, a DVD-RAM, a semiconductor memory, or the like. Further, the present invention may be the computer program or the digital signal recorded on these recording media.

In the present invention, the computer program or the digital signal may be transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, or the like. The present invention may also be a computer system including a microprocessor and a memory, wherein the memory stores the computer program, and the microprocessor operates according to the computer program.

Further, the computer or the digital signal is recorded on the recording medium and transferred, or the program or the digital signal is transferred via the network or the like, so that another computer system becomes independent. May be implemented. (8) The above embodiments and the above modifications may be combined.

[0048]

As described above, the present invention relates to a multicast transfer apparatus for transferring one transfer data in real time to a plurality of connected receivers by an asynchronous transfer method. Transfer data storage means for storing transfer data, information acquisition means for acquiring device information relating to each of the receiving devices from a plurality of connected reception devices, and information storage means for storing the acquired plurality of device information And a data transfer unit that transmits the transfer data to each receiving device while switching the receiving device to which the transfer data is transferred according to each device information stored in the information storage unit.

According to this configuration, it is possible to perform multicast transfer from one device to a plurality of other devices. Here, the data transfer means may be configured to switch the receiving device to which the transfer data is transferred so that each receiving device can receive the transfer data within a predetermined time zone. Further, the data transfer means may be configured to switch the receiving device to which the transferred data is transferred so that the time required to transfer the transferred data to each receiving device is equal. Further, the data transfer means may be configured to switch the receiving device to which the transfer data is transferred so that the amount of data to be transferred to each receiving device is equal.

According to these configurations, data can be transferred to each receiving device in real time. Here, the multicast transfer device performs data transfer using any one of a plurality of communication protocols, and further,
The communication device includes a selection unit that selects one of a plurality of communication protocols, the device information has a common data format for the plurality of communication protocols, and the information acquisition unit includes:
Acquiring device information having a common data format, the information storage means stores device information having a common data format, and the data transfer means, for each receiving device, according to a selected communication protocol, The transmission data may be transmitted.

According to this configuration, in one multicast transfer device, any one of a plurality of communication protocols
Can be used to transfer data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a data transfer system 1.

FIG. 2 is a block diagram showing a configuration of a VTR reproducing device 1.

FIG. 3 is a data structure diagram showing a data structure of a task table.

[FIG. 4] XFER_START_CHECK register 251 and XFER_END
FIG. 4 is a data structure diagram showing a data structure of a _CHECK register 252.

FIG. 5 is a flowchart showing a data transfer processing operation.

FIG. 6 is a flowchart showing an operation of data packet transmission.

FIG. 7 is a flowchart illustrating an operation of updating a task table.

FIG. 8 is a conceptual diagram showing a data transfer method using a page table defined by the SBP2 protocol.

FIG. 9 shows a data structure of a page table defined by the SBP2 protocol.

FIG. 10 is a conceptual diagram illustrating a data transfer method according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 VTR reproduction apparatus 2 Digital TV apparatus 3 Personal computer 5 Data transfer system 10 Application section 11 Firmware section 111 Task management section 113 Transfer start section 114 Communication control parameter generation section 115 Task table generation section 12 LSI section 122 DMA control section 123 Transfer start Parameter setting unit 124 Task table setting unit 125 Data transfer control unit 126 Task table control unit 127 Task table storage unit 13 OSD data storage unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Isamu Ishimura 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5C018 FA00 FA04 FB03 FB09 5C025 AA23 AA30 BA21 CA02 CA09 DA01 5K030 GA02 HB02 HC14 KA02 LD04 5K033 AA02 BA01 CB13 5K034 AA03 CC03 DD02 HH01 HH02 HH63

Claims (6)

[Claims] 1. A multicast transfer device for transferring one transfer data in real time to a plurality of connected receiving devices by an asynchronous transfer method, wherein the transfer data storage stores one transfer data. Means, information acquisition means for acquiring device information relating to each receiving device from a plurality of connected receiving devices, information storage means for storing the acquired plurality of device information, and information storage means A multicast transfer device, comprising: a data transfer unit that transmits the transfer data to each of the receiving devices while switching a transfer destination of the transfer data according to each device information. 2. The data transfer unit according to claim 1, wherein the data transfer unit switches the receiving device to which the transfer data is transferred so that each receiving device can receive the transfer data within a predetermined time zone. Multicast forwarding device. 3. The transfer device according to claim 2, wherein the data transfer unit switches the transfer destination of the transfer data so that the time required to transfer the transfer data to each of the reception devices becomes equal. The multicast transfer device according to the above. 4. The data transfer device according to claim 2, wherein the data transfer unit switches the receiving device to which the transfer data is transferred so that the amount of data to be transferred to each receiving device is equal. Multicast transfer device. 5. The multicast transfer device performs data transfer using any one of a plurality of communication protocols, and further includes a selection unit that selects one of the plurality of communication protocols. The information is, for the plurality of communication protocols,
A common data format, the information acquisition unit acquires device information having a common data format, the information storage unit stores device information having a common data format, and the data transfer unit includes: The multicast transfer device according to claim 1, wherein the transfer data is transmitted to each receiving device according to the selected communication protocol. 6. A transfer data storage means for transferring one transfer data in real time to a plurality of connected receiving devices by an asynchronous transfer method and storing one transfer data; A multicast transfer method for use in a multicast transfer device, comprising: an information storage unit for storing device information of a plurality of connected reception devices; And a data transfer step of transmitting the transfer data to each receiving device while switching the receiving device of the transfer data according to each device information stored in the information storage means. A multicast transfer method comprising: