JP2005328240A - Bitstream parallel transmission system, transmission method and apparatus using TCP - Google Patents

Abstract

A bit stream that is continuously input can be transmitted in real time, and a marginal transmission rate can be increased.
A bitstream parallelization device 61 that inputs a single bitstream, divides it into a plurality of bitstreams, and outputs the data, receives data from the parallelization device 61, and passes through an IP network 68 The transmission computers 64 and 66 that transmit data frames to a fixed destination by TCP communication and the data frames received via the IP network 68 are received, and the data is transmitted in a cycle based on the clock signal for synchronous operation. A bit stream serial for reorganizing and outputting a plurality of input data frame sequences into one bit stream in synchronization with the receiving computers 65 and 67 and the receiving computers 65 and 67 based on the synchronous operation clock signal Frequency for supplying synchronization operation clock to serializing device 62 and serializing device 62 and receiving computers 65 and 67 And a quasi-vessel 63.
[Selection] Figure 6

Description

  The present invention relates to a bitstream parallel transmission system based on TCP, and in particular, a system configuration, a transmission method, a parallelization device, and a serialization for transmitting a continuously input bitstream in real time to improve a limit transmission speed The present invention relates to a device, a transmission computer, a reception computer, a frequency standard device, and a bit stream transmission device.

  In real-time transmission of a bit stream on an IP network, it is common to use UDP. However, since UDP does not guarantee the arrival of each IP packet at the destination, it is not suitable for real-time delivery of ultra-high-definition images and real-time processing of experimental data. On the other hand, TCP is limited in transmission speed by distance due to its retransmission function. Therefore, it has been performed to divide data to be transmitted in order to perform high-speed transmission using TCP and perform parallel transmission using a plurality of TCP streams. There are multiple things implemented in software. Software called bftp is a representative one of them.

From the above, when deciding which protocol to use, TCP or UDP, it is necessary to select according to the application. TCP is used when it is desired to realize reliable communication over a wide area Internet. Further, although it does not matter if it is not particularly high-speed, it is used when it is desired to perform communication with a certain level of performance, whether it is a LAN or WAN, whether the network is free or the network is congested. When TCP is used, since retransmission processing is performed when data is lost, the data arrival interval may not be constant, and the image and sound may stop for a while or may be fast-forwarded.
When data is transmitted using TCP, it reaches the partner computer in the order of transmission. However, the break of data when transmitted is not known. A stream is a seamless data structure. In TCP, order control and retransmission control are performed to achieve reliability. It also has functions such as flow control (flow rate control), congestion avoidance control, and a network utilization efficiency improvement mechanism.

In contrast, UDP is used when the amount of data is small or when it is desired to communicate at high speed within a LAN. In addition, UDP is used to deliver video images and audio images with a video conference system or the like. When multicast or broadcast communication is desired, TCP cannot be used, so UDP must be used.
UDP is an unreliable datagram type protocol. Detailed processing is determined by the upper layer application. Although the size of the data at the time of transmission is maintained, there is no guarantee that the packet will arrive, so the application must perform retransmission processing as necessary.
A protocol field is defined in the IP header, and a number representing a transport protocol is described here. This number identifies whether the data carried by the IP is TCP or UDP (Takashi Takeshita et al., “Mastering TCP / IP Introduction 2nd Edition” (Ohm, May 1998) Issued 25th, P.168-170) (see Non-Patent Document 1)).

Takashi Takeshita, Koho Murayama, Toru Arai, Yukio Hamada, “Mastering TCP / IP Introduction 2nd Edition” (Ohm, May 25, 1998, P.168-170) bbFTP, Gilles Farrache [online], December 24, 2003 (updated), Internet <URL: http: // doc. in2p3. fr / bftp / index. html>

  As described above, the conventional TCP parallel transmission technique is a technique for transmitting data statically stored in a transmission-side PC (personal computer). In the conventional method, basically, a plurality of TCP sessions are set up between a pair of transmission side PCs and reception side PCs. Therefore, transmission and reception loads are concentrated on one PC and transmission is performed. There was a limit to the increase in speed.

(the purpose)
An object of the present invention is to solve such a conventional problem, transmit a bit stream that is continuously input in real time, and increase the marginal transmission rate, and a bit stream parallel transmission system using TCP. And a transmission method and apparatus.

  In the present invention, the bit stream is divided into a plurality of bit streams, the divided bit streams are transmitted in parallel by TCP, and the TCP streams received in parallel are reconfigured in the order before the division. Then, the bitstream is parallelized and serialized by hardware to perform real-time parallel transmission of the bitstream. In addition, by performing transmission / reception by TCP among a plurality of PCs, load distribution is performed and a limit transmission speed is increased.

  According to the present invention, a continuously input bit stream can be transmitted in real time, and the limit transmission rate can be increased. In addition, since TCP transmission / reception is performed between a plurality of PCs, load distribution can be performed.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing an operation example of a parallelization apparatus to which the present invention is applied.
Here, it is assumed that the input bit stream is divided into n streams. The parallelizing device 11 has one input port and n output ports.
The parallelizing device 11 divides the input bit stream into data frames of the same size from the top. D ¹ ₁ , D ² ₁ ,..., D ⁿ ₁ , D ¹ ₂ , D ² ₂ ,..., D ⁿ ₂ , ..., D ¹ ₃ , D ² _3. To do. It is distributed to each output port in the order of input in the round robin method. As a result, data in which D ¹ ₁ , D ¹ ₂ , D ¹ ₃ ,... Are sequentially connected is output to the output port ₁ , and D ² ₁ , D ² ₂ , D ² _3.・ Outputs data that is connected in order. Similarly, data in which D ^k ₁ , D ^k ₂ , D ^k ₃ ,... Are sequentially connected is output to the output port k (1 ≦ k ≦ n).

FIG. 2 is an explanatory diagram showing an operation example of the serialization device to which the present invention is applied.
Here, it is assumed that n input data frame sequences are rearranged into one bit stream and output. The serializer 21 has n input ports and one output port. Further, it has an interface for receiving a clock signal for synchronous operation from the outside. Further, for each input port, one by one memory _{M 1, M 2, M 3} , with · · _{M n.} A memory corresponding to the input port k (1 ≦ k ≦ n) is _defined as M _k . Data input from the input port k is stored in the memory _Mk .
The serializer 21 periodically reads out the stored data frames having the earliest arrival for each memory, arranges them, and outputs them from the output port. The memory area where the output data is stored is released simultaneously with reading. At this time, when the data read from the Mk and _{Dk, D 1, D 2,} D 3, and outputs in the order of · · · _{D n.} The period of this operation is determined from a clock signal input from the outside (frequency standard device).

FIG. 3 is an explanatory diagram showing an operation example of the transmission PC to which the present invention is applied.
The transmission PC 31 has an interface 33 for receiving data transmitted by the parallelization device 11 and an IP network interface 34. Further, for each transmission PC 31, a transmission destination reception PC is fixed.
The transmission PC 31 stores the data frame sent from the parallelizing device 11 in the internal storage medium 32. At the same time, the stored data is transmitted via the IP network to the receiving PC corresponding to the reception order via TCP (35), and the transmitted data is erased from the internal storage medium 32.

FIG. 4 is an explanatory diagram showing an operation example of the receiving PC to which the present invention is applied.
The reception PC 41 has an interface 44 for transmitting data to the serialization device 21 and an IP network interface 43. Furthermore, it has an interface for receiving a clock signal for synchronous operation from the outside (frequency standard device).
Each receiving PC 41 stores the data frame received through the IP network in the internal storage medium 42. When the total amount of stored data reaches a predetermined threshold, transmission of the stored data frame to the serialization device 21 is started. This transmission is performed simultaneously by the receiving PCs 41 in a cycle based on clocks supplied from the outside in the order of arrival.

FIG. 5 is an explanatory diagram showing a cooperative operation between the serialization device and the receiving PC to which the present invention is applied.
The serializing device 52 and each of the receiving PCs 53 and 54 perform the operations described in FIG. 2 and FIG. 4 in synchronization based on the clock signal from the same frequency standard 51. That is, the data frame is transmitted from the receiving PCk number to the kth port of the serialization device, and then the data frame is read from each memory _Mk , connected and output as a bit stream. Transmission from the receiving PC to the serializing device and transmission from the serializing device are processed in synchronization by the clock signal from the frequency standard 51. As a result, the following two points are realized.
(1) The data transmission of the receiving PCs 53 and 54 to the serializing device 52 and the data output from each memory _Mk are performed at the same speed to prevent memory overflow and data loss.
(2) The data D ₁ , D ₂ , D ₃ ,... D _n transmitted simultaneously by the receiving PCs 53 and 54 are always D _k = D ^kn _i (1 ≦ k ≦ n) for the same i. .

FIG. 6 is a diagram showing an overall configuration of a system in which devices to which the present invention is applied and an example of a flow.
The transmitting PCk transmits data to the receiving PCk having the same number. Thereby, the divided data is reproduced without making a mistake in the order.
In addition, the receiving PCs 65 and 67 do not immediately transmit the data received from the transmitting PCs 64 and 66 to the serializing device 62 but transmit them after temporarily storing them in the internal storage medium. As a result, delays and fluctuations in data arrival are absorbed in the receiving PCs 65 and 67, and the input to the serializing device 62 becomes regular.
The frequency standard 63 supplies a synchronous clock signal to the serializing device 62 and the plurality of receiving PCs 65 and 67. The parallel data input to the inputs 1... N of the serializer 62 from the receiving PCs 65 and 67 is accumulated in the memories M ₁ ... M _n , and the bit stream input to the parallelizer 61 is reproduced. Is output.

Next, a specific example of an existing parallel transmission system using TCP will be described.
As described in bbFTP, Gilles Farrache [online], published on December 24, 2003 (see Non-Patent Document 2), file transfer software called bbFTP is used. This software is applied to the transmission of large files over 2GB. The characteristics of bbFTP are as follows.
(B) The user name and password at the time of connection are encrypted.
(B) A certification module is used for SSH and certificates.
(C) Multi-stream transmission is performed.
(D) Large Windows (registered trademark) defined by RFC1323 is used.
(E) Data compression is possible very quickly.
(F) Automatic retry is possible.
(G) It will time out idiomatically.
(H) Transmission simulation is possible.
(I) AFS (Andrew File System) is performed in an integrated manner.
(Nu) A wireless I / O interface is used.

An FTP site installed internally by a company or university gives an ID and a password to a related person, and requests an ID and password from a user who accesses the FTP site for authentication.
Several commands (command statements) are prepared in the FTP. There are an OPEN command for calling a partner computer, a GET command for downloading a file, a PUT command for uploading a file, and a CD command for moving up and down a directory.
If you use FTP clients that are widely available as freeware and shareware, you can easily copy files using the mouse in a graphical environment such as Windows (registered trademark) or Macintosh without entering such commands on the keyboard. be able to.

It is a block diagram of the parallelization apparatus which this invention applies. It is a block diagram of the serialization apparatus which this invention applies. It is a block diagram of the computer for transmission to which this invention applies. It is a block diagram of the computer for reception to which this invention applies. It is a connection block diagram and a flow diagram of a receiving computer and a serialization device to which the present invention is applied. 1 is an overall configuration diagram and a flowchart of a bitstream parallel transmission system using TCP according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Parallelizer, 21 ... Serializer, 31 ... Computer for transmission, 32 ... Internal storage medium,
33 ... Data reception interface, 34 ... IP network interface,
35 ... operation for transmitting to the IP network in the order of reception from the parallel device,
41 ... Receiving computer, 42 ... Internal storage medium,
43 ... IP network interface,
44. Interface for data transmission to serializer,
45... Transmits data to the serializer in a cycle based on the clock signal from the frequency standard.
51 ... Frequency standard, 52 ... Serializer, 53, 54 ... Receiving computer,
61 ... Parallelizing device, 62 ... Serializing device, 63 ... Frequency standard,
64, 66 ... transmission computer, 65, 67 ... reception computer.

Claims (7)

A bitstream parallelization apparatus that inputs one bitstream, divides it into a plurality of bitstreams, and outputs it;
A transmission computer that receives data from the parallelization device and transmits a data frame by TCP communication to a fixed destination via an IP network;
A receiving computer for receiving a data frame received via the IP network and transmitting data in a cycle based on a clock signal for synchronous operation;
A TCP having a bit stream serializing device for reorganizing a plurality of input data frame trains into one bit stream in synchronization with the receiving computer based on the clock signal for synchronous operation; By bitstream parallel transmission system. The bitstream parallelization device divides the input bitstream into a plurality of bitstreams,
The bitstream parallelization apparatus transmits the divided bitstream to a transmission computer,
Each sending computer temporarily stores the received data in an internal storage medium,
Each of the transmission computers transmits the data stored in the internal storage medium to the corresponding reception computer via TCP communication.
Each receiving computer temporarily stores the received data in an internal storage medium,
Each of the receiving computers transmits the data stored in the internal storage medium in order to the bit stream serializer,
The bitstream serialization device reconstructs the received data in the order before being divided by the bitstream parallelization device, and outputs it as a bitstream.
A bitstream parallel transmission method using TCP, wherein each of the above processes is continuously performed while the bitstream is input to the bitstream parallelization apparatus.   One input port, a plurality of output ports, and a means for dividing the input bit stream into data frames of the same size from the top and distributing them to each output port in the order of input from the top data frame in a round robin manner. Means for outputting data connected in order from the output port.   A plurality of input ports, one output port, an interface for receiving a clock signal for synchronization operation from the outside, one assigned to each input port, and data input from the input port is temporarily stored And a means for reorganizing a plurality of input data frame sequences into one bit stream and outputting the same in synchronism with the clock for synchronization operation. apparatus.   An interface for receiving data sent from the parallel device, a network interface connected to the IP network, and storing the received data frame in the internal storage medium, and receiving the stored data frame in parallel therewith A bitstream transmitting computer comprising: a receiving computer that sequentially corresponds to the TCP through an IP network.   An interface for transmitting data to the serialization device, an interface for the network connected to the IP network, an interface for receiving a clock signal for synchronization operation from the outside, and a data frame received via the IP network are internally stored When the total amount of stored data frames reaches a predetermined threshold, transmission of the stored data frames to the serializer is started in synchronization with the external synchronization clock. And means for receiving a bit stream.   The clock signal receiving interface of each of a plurality of receiving computers and the clock signal receiving interface of at least one serializing device are connected to each other, and a means for supplying a clock signal for synchronous operation is provided. A frequency standard.

Images