JPH11215185A - Device and method for transmitting data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit data which are processed at a receiving station while the data are temporarily stored in the station at a stable high throughput regardless of the occurrence of packet losses. SOLUTION: A data separating means 12 classifies the data outputted from a packet transmitting means 11 into resending data and non-resending data normally transmitted in the first packet, outputs the resending data to a resending data holding means 14, and successively outputs the non-resending data to a temporarily storing means 13. The holding means 14 holds the resending data which are generated during the transmitting period of a series of data and collectively outputs the resending data after the transmission of the series of data is completed. A data interpolating means 15 interpolates the non-reseding data outputted from the storing means 13 with the resending data outputted from the holding means 14 and outputs the interpolated data to a data processing means 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting a large amount of data from a transmitting data transmitting apparatus (hereinafter referred to as a transmitting station) to a receiving data transmitting apparatus (hereinafter referred to as a receiving station) via a transmission path having a large band delay product. The present invention relates to a data transmission technique suitable for performing high-speed data transmission without error by dividing the data into packets, and subsequently performing data processing asynchronously with the data transmission.

[0002]

2. Description of the Related Art FIG. 1 shows a general configuration of a data transmission apparatus. In FIG. 1, a data transmission device includes a transmitting station 1 and
It comprises a receiving station 2 and a transmission line 3 connecting the two. There is a round-trip delay between the transmitting and receiving stations that is proportional to the distance.

FIG. 2 shows a configuration example of a conventional general data transmission apparatus. In FIG. 2, a series of data input to the packet transmission unit 4 is transmitted via the transmission line 3 and processed by the data processing unit 7.

When data transmission and data processing are performed asynchronously, a temporary storage unit 6 for temporarily storing a series of data output from the packet transmission unit 4 is required.

[0005] The packet transmission means 4 divides the input data, packetizes it, and transmits it. At this time, a transmission error may occur on the transmission path 3 and a packet may be lost. If part of a series of data is lost due to packet loss, the data processing means 7 cannot execute correct processing. Therefore, the packet transmission means 4 detects the loss of the packet during transmission, packetizes the data of the corresponding portion (hereinafter, retransmission data) again, and retransmits the data, thereby reliably transmitting all the input data. .

In general, in a transmission path having a large transmission band × round trip delay (hereinafter referred to as a band delay product), the retransmission method is a selective retransmission method that achieves high transfer efficiency by retransmitting only data in a lost portion. Is adopted.
In the selective retransmission method, when a packet loss occurs, the data of the lost portion arrives later than the data of the subsequent portions. For this reason, the receiving station needs an order correcting means 5 for waiting for the arrival of retransmission data and outputting data in order.

FIG. 3 shows an example of the output from the sequence correcting means 5 in the case where the data packet of the part (i) is lost and up to the data of the part (i + 3) has been transmitted before retransmission. As illustrated in FIG. 3, the data after the loss part received before the data of the packet loss part is held in the sequence correcting means 5 from the occurrence of the packet loss to the arrival of the retransmission data, and the output is delayed. Is done.

[0008] That is, retransmission delay time from occurrence of packet loss to arrival of retransmission data: T, data transfer rate:
The following relationship holds between R and the storage capacity of the order correcting means: L.

[0009]

R <L / T Equation (1) As is apparent from Equation (1), a higher data transfer rate:
In order to perform data transfer with R, it is necessary to shorten the retransmission delay time: T and increase the storage capacity: L of the order correction means.

However, in order to reduce the retransmission delay time: T, it is necessary to detect the occurrence of packet loss earlier and start the retransmission process. In other words, the receiving station checks the packet loss in a shorter cycle, and if a packet loss is detected, it is necessary to process a packet retransmission request in parallel while continuing a series of data reception. There is. Therefore, as the data transfer rate increases, the data transfer control process becomes more busy, and higher processing performance is required for hardware such as a CPU that executes the data transfer.

Also, since the retransmission delay time T includes a round trip delay proportional to the distance between the transmitting and receiving stations, the storage capacity L of the order correcting means increases as the transmission distance increases. I have no choice. In order correction means,
By performing data writing to an arbitrary position on the storage medium or reading data from the arbitrary position, the order correction processing is realized. Therefore, it is necessary to use a semiconductor memory having a high I / O throughput at the time of random access as a storage medium.

Further, the storage capacity of the order correcting means is as follows:
The increase in the capacity of L increases the delay of data output from the sequence correction means 5 when a packet loss occurs, and suppresses the time that can be spent for data input to the temporary storage means 6. For this reason, the temporary storage means 6 is required to have a storage medium with a higher I / O throughput.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and makes it possible to temporarily store received data in a receiving station regardless of the occurrence of packet loss.
An object of the present invention is to realize a data transmission device that performs stable and high throughput at lower cost.

[0014]

With the recent advances in optical fiber and VLSI technology, the transmission bandwidth of transmission lines is becoming an order of several gigabits / second, and at the same time, the transmission quality is increased. The bit error rate is very high, ie, less than 10S and less than P-12E. In data transmission via such a high-speed and high-quality transmission path, packet loss is extremely rare.
Most data is received continuously without the need for order correction.

Further, in the prior art, before the data is input to the temporary storage means 6, the order is corrected by the sequence correction means 5 without any data being lost. This is because, even when the temporary storage means 6 is not provided in FIG. 2, the configuration up to the preceding stage can be used for general purposes. But,
Assuming that the temporary storage means 6 exists, if the data is not lost at the time of data input from the temporary storage means 6 to the data processing means 7 and the order is correct, the processing in the data processing means 7 has no problem. Does not occur.

In the present invention, attention is paid to the above two points, and the following three means are provided in place of the order correcting means in the conventional means configuration, thereby simplifying the data transfer control processing, and continuously Data is input to the temporary storage means at a stable rate.

Data Separation Means The data separation means discriminates data output from the packet transmission means into retransmission data and non-retransmission data normally transmitted in the first packet. The retransmission data is output to the retransmission data holding unit. Also, non-retransmission data is
Output to the temporary storage means sequentially.

Retransmission data holding means The retransmission data holding means holds retransmission data generated during the transmission period of a series of data, and outputs the data at once after the transmission of the series of data.

Data interpolation means The data interpolation means is provided before the data input to the data processing means. The data interpolation means interpolates the non-retransmission data output from the temporary storage means with the retransmission data output from the retransmission data holding means and outputs the result to the data processing means. As a result, the data processing means does not lose
Data is input in the correct order, and normal processing can be performed.

In the retransmission data holding means, a method is conceivable in which, after the transmission of a series of data, retransmission data is rearranged in order from the head and output. In this case, it is necessary to realize the retransmission data holding means in a semiconductor memory having good responsiveness even at the time of random access and high I / O throughput. The amount of generated retransmission data is small, and the capacity of the semiconductor memory does not matter.

For example, in the prior art, the data transfer rate: R is 1 gigabit / second (1 giga is 10 9),
Retransmission delay time: When T is 100 milliseconds, a storage capacity of 10 megabytes (1 Giga is 10 6) or more is required for the order correction means, but the amount of data transmitted at one time Is 1 gigabyte (1 giga is 10 9), which is on the order of the hard disk capacity of the current general personal computer, and the packet length is a standard LAN.
When the packet loss is caused by only a bit error on the transmission path, the amount of data lost during one data transmission is very small, 1500 bytes or less.

Since the temporary storage means is generally required to have a large capacity, a magnetic disk is used as a storage medium. As shown in the schematic diagram of FIG. 4, the magnetic disk has an I / O throughput characteristic that is less responsive than a semiconductor memory or the like. Therefore, as shown in FIG. 5, the larger the amount of data that is continuously I / Oed, the higher the I / O throughput can be obtained.

In the present invention, such a magnetic disk I
In consideration of the I / O characteristic, the received non-retransmission data is sequentially and continuously input at a stable rate to the temporary storage means, so that I / O to a continuous area on the storage medium of the magnetic disk is performed. Encourage opportunities and avoid overhead such as head seek delay.

In addition, even when a packet loss occurs, there is no delay in inputting data to the temporary storage means due to waiting for retransmission data in the order correction means, so that the time spent for data input to the temporary storage means is reduced. Therefore, a storage medium having a lower I / O throughput than that of the related art can be used.

Further, since the request for the retransmission delay time T is relaxed, the receiving station checks the packet loss at a more gradual cycle, and when the packet loss is detected, a series of data is transmitted. After the end of the reception, it becomes possible to process the packet retransmission request collectively. Therefore, the control processing of the data transfer is simplified, and hardware having a lower processing capacity than the conventional technique can be used as hardware such as a CPU for executing the data transfer.

[0026]

Embodiments of the present invention will be described below. FIG. 6 shows the data transmission apparatus of the embodiment as a whole. In this figure, the data transmission apparatus comprises a packet transmission unit 11, a data separation unit 12, and a temporary storage unit 1.
3. It includes retransmission data holding means 14, data interpolation means 15, and data processing means 16.

As in the prior art, the packet transmission means 11
Are transmitted from the transmitting station 1 to the receiving station 2
(See FIG. 2), stored in the temporary storage unit 13, and processed by the data processing unit 16.

In this embodiment, the packet transmission means 1
The data output from 1 is separated by the data separation means 12 into non-retransmission data and retransmission data. The data determined to be non-retransmission data by the data separation unit 12 is temporarily stored in the temporary storage unit 13. On the other hand, data separation means 1
The data determined to be retransmission data in 2 is held by the retransmission data holding unit 14 during a series of data transmission.

The data interpolation means 15 uses the retransmission data output from the retransmission data holding means 14 and
3 is interpolated and output to the data processing means 16.

FIG. 7 shows a configuration example of the packet transmission means 11. In FIG. 7, the packet transmission unit 11 includes a data holding function 111, a sequential transmission function 112, a retransmission function 113,
It is configured to include a packet transmission function 114, an error detection function 115, and a delivery confirmation function.

In the packet transmitting means 11, a series of data is sequentially input to the data holding function 111 from the beginning to the end. The data holding function 111 holds the data input at the transmitting station 1 (see FIG. 2) until the transmission to the receiving station 2 (see FIG. 2) is confirmed.

The sequential sending function 112 has the data holding function 1
11 is sequentially read out in packet units, packetized by adding order information indicating the context of the data held in the packet, and an error detection code for detecting a data transmission error. Send out.

As the order information, a serial number and a data length for the first octet of the data in the packet are added. The serial numbers are aligned between the transmitting and receiving stations at the start of a series of data transmission, and are sequentially allocated to the data input to the data holding function in octet units from the beginning. If the data length is fixed, a serial number may be assigned to each packet.

The packet transmission function 114 transmits a packet from the transmitting station 1 to the receiving station 2. During packet transmission, a transmission error occurs in the data held in the packet, or the packet itself is lost.

The error detection function 115 checks the data held in the received packet for a transmission error. If a transmission error is detected, the packet is discarded. If no transmission error is detected, the packet is discarded. In this case, the data and its order information are transferred to the data separating means 12 (FIG. 6).
Output). When a transmission error is detected by the error detection function 115 or when a packet is lost by the packet transmission function 114, the order information of the received data is lost.

In the retransmission function 113, based on this order information, the data that has been transmitted by the transmitting station but has not been received by the receiving station 2 is specified, and the corresponding data is read out again from the data holding function 111. , And retransmitted.

The delivery confirmation function 116 specifies the received data based on the order information, and the data holding function 111
, The corresponding data is discarded, and input of new data is prompted.

FIG. 8 shows an example of the configuration of the data separating means 12. 8, the data separating unit 12 includes a data output destination switching function 121, a serial number comparing function 122, and a latest serial number register 123.

In order for the data separation means 12 to distinguish between non-retransmission data and retransmission data, the data separation means 1
2 has a latest serial number register 123 for holding the latest serial number. In this embodiment, a case where the data length held in the packet is not fixed is shown. That is, the latest serial number indicates the serial number of the first octet of the non-retransmission data that is expected to arrive next.
The case where the data length in a packet is fixed and a serial number in a packet unit is used can be similarly realized based on the present embodiment.

FIG. 9 shows an operation example of the data separating means 12. In FIG. 9, at the start of a series of data transmission, the data separating unit 12 resets the register value with the value aligned between the transmitting and receiving stations as an initial value (S11).

During the transmission period, when data is input (S12), the serial number is compared with the register value,
If they are the same, the input data is determined to be non-retransmission data, the register value is set to a value obtained by updating the serial number of the input data by the data length, and the data is output to the temporary storage means. (S13, S14, S1
5).

Even when the register value is older than the serial number of the input data, the input data is determined to be non-retransmitted data. However, since the discontinuous part of the serial number should be retransmitted data, Outputs the register value, and outputs the difference between the serial number of the input data and the register value as the data length, and then updates the serial number of the input data by the data length. Is set to the register value, and the data is
3 (S13, S16, S15).

If the register value is newer, the input data is determined to be retransmission data, the register value is stored, and the data, its serial number, and the data length are output to the retransmission data holding means 14 (S13). , S17).

The data separating means 12 repeats the above operation until the end of a series of data transmission (S18).

FIG. 10 shows a first configuration example of the retransmission data holding means 14. In FIG. 10, retransmission data holding means 1
4 includes a retransmission data holding memory 141, a serial number comparison function 142, and a retransmission data list holding memory 143.

In this configuration example, retransmission data generated during a series of data periods is stored in a retransmission data holding memory 141 composed of a semiconductor memory having a small overhead at the time of random access, and is collected at the start of processing. Here is an example of output.

The retransmission data holding means 14 stores, as a set of entries, the retransmission data serial number, the data length, and the address in the retransmission data holding memory 141 in which the data is stored, and sets the retransmission data / order in the order of the serial numbers. A list is prepared, and a retransmission data list holding memory 143 for holding the list is provided. This is because, in order for the data interpolation unit 15 to reconstruct the data without error, the retransmission data holding unit 14 must output the retransmission data from the oldest serial number without fail. FIG. 11 shows an example of the retransmission data list.

FIG. 12 shows a second configuration example of the retransmission data holding means 14. 12, the retransmission data holding unit 14 includes a retransmission data holding memory 141, a serial number comparison function 142, a retransmission data list holding memory 143, and a retransmission data and retransmission data list temporary storage disk 144. In this configuration example,
Retransmission data generated during a series of data
The data is held in a retransmission data holding memory 141 composed of a semiconductor memory with a small overhead at the time of access, and temporarily stored in a storage area (temporary storage disk) 144 composed of a magnetic disk after the transmission is completed. An example is shown in which the information is output collectively at the start of the processing.

FIG. 13 shows an operation example of the retransmission data holding means 14. In FIG. 13, the retransmission data list is reset to a state without retransmission data at the start of a series of data transmission (S21).

The input of retransmission data from the data separation means 12 to the retransmission data holding means 14 is performed in the following two stages.

If the serial number of the input data is newer than the register value in the data separating means 12, the discontinuous portion of the serial number should be retransmitted data. And the data length are output to the retransmission data holding unit 14 (S13, S13).
17, see FIG. 9).

Upon receiving the serial number and data length of the data expected to be delayed, the retransmission data holding means 14 adds the corresponding entry to the retransmission data list (S2).
2, S23, S24). At this time, a value indicating that data has not arrived is set in the address value on the retransmission data holding memory where the data is to be held.

If the serial number of the input data is older than the register value in the data separating means 12, the data is determined to be retransmission data, and is output to the retransmission data holding means 14 together with the serial number and data length. (S
13, S16, see FIG. 9).

On the other hand, the retransmission data holding means 14 searches the retransmission data list for an entry that matches the input retransmission data or includes the input retransmission data, and there is no entry. In this case, the input data is discarded (S22, S23, S25, S2
6, S29).

If there is an entry that includes the input retransmission data, the entry is divided into an entry that matches the input retransmission data and an entry consisting of other parts (S26, S27). . Specifically, the entry containing the input retransmission data is deleted from the retransmission data list, and instead,
An entry matching the input retransmission data is inserted, and an entry consisting of another part generated by the division is inserted before, behind, or both of them.

Then, by referring to the entry that matches the retransmission data, if the data is already stored in the retransmission data holding memory, the input data is discarded (S2).
8, S29) If not, data is written to a free area in the retransmission data holding memory, and the start address is set in the corresponding entry (S30).

When a series of transmissions is completed, the retransmission data holding means 14 refers to the entries held in the retransmission data list in the order of the oldest, and sets the serial number, data length, and retransmission data of the retransmission data held in each entry. The corresponding retransmission data held in the holding memory is sequentially output (S
31, S32).

FIG. 14 shows an example of the configuration of the data interpolation means 15. In FIG. 14, the data interpolation means 15 includes a data input source switching function 151, a serial number comparing function 152, a last serial number register 153, and a latest serial number register 1
54.

The data interpolation means 15 has a latest serial number register 154 for holding the latest serial number in order to determine the boundary of the data block of the non-retransmission data input from the temporary storage means 13. Here, the latest serial number indicates the serial number of the first octet of data to be output next.

In order to know the end of the data to be output, a final serial number register 1 for holding the final serial number
Has 53. Here, the last serial number indicates the serial number of the octet next to the last octet of the data to be output.

FIG. 15 shows an operation example of the data interpolation means 15. In FIG. 15, the latest serial number register value is reset to the serial number value at the start of the corresponding series of transmissions when the output of the data resulting from the series of transmissions to the data processing means 16 is started (S41). ). Similarly, the last serial number register value is reset to the serial number value at the end of the series of transmissions (S41).

When outputting data to the data processing means 16, the data interpolation means 15 first inputs each entry of the retransmission data list output from the retransmission data holding means 14 to the packet transmission means 11 in chronological order. The serial numbers of the retransmission data stored in the entry are compared with the latest serial number register value (S43). Here, if the serial number stored in the latest serial number register 154 is older, the data length of the data block of the non-retransmitted data preceding the retransmitted data is obtained from the difference between the serial numbers of both, and the amount of the non-retransmitted data of that amount is obtained. Is input from the temporary storage unit 13 and output to the data processing unit 16 (S44). Subsequently, retransmission data corresponding to the previously read order information is input and output to the data processing means 16 (S45). The register value is set to a value obtained by updating the serial number of the retransmission data by the data length (S46).

If the serial number held in the latest serial number register is the same as the serial number of the retransmission data, retransmission data corresponding to the order information is input and output to the data processing means 16, and the latest serial number register value is The serial number of the retransmission data is further set to a value updated by the data length (S43, S45, S46).

It is assumed that the serial number held in the register is newer than the serial number of the retransmission data in a normal state.

As described above, the data interpolation means 15
Interpolation of non-retransmission data by retransmission data is repeated until input of all entries from retransmission data holding means 14 is completed, and when entry input from retransmission data holding means 14 is completed, the last serial number register value and the latest serial number register value are updated. The data length of the data block of the remaining non-retransmission data is obtained from the difference, the amount of the non-retransmission data is input from the temporary storage unit 13 and output to the data processing unit.
The operation ends (S47, S48).

[0066]

According to the present invention, a large amount of data is transmitted at high speed through a transmission path having a large band delay product without error, and received data is temporarily stored for processing asynchronously with transmission. In addition, it is possible to realize a data transmission device that performs data transmission with stable and high throughput at lower cost.

More specifically, first, the capacity of a semiconductor memory having a high I / O throughput at the time of random access can be significantly reduced as compared with the prior art. This is because in the prior art, a capacity equal to or more than the product of the data transmission rate and the retransmission delay time is required to constitute the order correction means, whereas in the present invention, the memory for constituting the retransmission data holding means is required. This is because the capacity is determined by the amount of data transmission at one time and the rate of occurrence of packet loss.As the transmission bandwidth of the transmission path improves and the rate of occurrence of packet loss decreases, the difference in the required memory capacity between the two is: It is expanding.

Next, as a second point, it is possible to use a storage medium having a lower I / O throughput as compared with the prior art for the configuration of the temporary storage means. This is, in the prior art,
When a packet loss occurs, data input delay to the temporary storage means occurs due to waiting for retransmission data in the order correction means, whereas in the present invention, non-retransmission data is sequentially input to the temporary storage means, This is because the data input rate to the temporary storage means is leveled.

Third, as compared with the prior art, hardware such as a CPU for executing control processing of data transfer can be used with lower processing capability.
This is because, in the present invention, the request for the retransmission delay time: T is relaxed, so that the receiving station checks the packet loss at a more gradual cycle. This is because it is possible to collectively process the packet retransmission request after the end of the data reception.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a data transmission device.

FIG. 2 is an explanatory diagram of a means configuration of a conventional data transmission device.

FIG. 3 is an explanatory diagram of data output from an order correcting means.

FIG. 4 is an explanatory diagram of a throughput characteristic of a magnetic disk.

FIG. 5 is an explanatory diagram of a throughput characteristic of a magnetic disk.

FIG. 6 is a block diagram showing an entire data transmission device according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of a configuration example of a packet transmission unit.

FIG. 8 is an explanatory diagram of a configuration example of a data separation unit.

FIG. 9 is an explanatory diagram of an operation example of a data separation unit.

FIG. 10 is an explanatory diagram of a configuration example of a retransmission data holding unit.

FIG. 11 is an explanatory diagram of an example of a retransmission data list.

FIG. 12 is an explanatory diagram of another configuration example of the retransmission data holding unit.

FIG. 13 is an explanatory diagram of an operation example of a retransmission data holding unit.

FIG. 14 is an explanatory diagram of a configuration example of a data interpolation unit.

FIG. 15 is an explanatory diagram of an operation example of the data interpolation means.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmitting station 2 receiving station 11 packet transmission means 12 data separation means 13 temporary storage means 14 retransmission data holding means 15 data interpolation means 16 data processing means

[Procedure amendment]

[Submission date] January 22, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

With the recent advances in optical fiber and VLSI technology, the transmission bandwidth of transmission lines is becoming an order of several gigabits / second, and at the same time, the transmission quality is increased. The bit error rate is very high, that is, 10 ^-12 or less. In data transmission via such high-speed and high-quality transmission paths,
Packet loss is very rare and most data is
Received continuously without the need for order correction.

Claims (22)

[Claims] 1. A data transmission apparatus for transmitting a packet from a transmitting station to a receiving station via a transmission line, wherein the transmitting station divides a series of data, and divides each of the divided data into a context of the divided data. And generating a packet by adding an error detection code for detecting a transmission error, sequentially transmitting the packet from the transmitting station to the receiving station via the transmission path, Then, a transmission error is detected using the error detection code in the received packet, and if no transmission error is detected, the order information corresponding to the data held in the packet is output, and the transmission error is detected. If detected, discard the packet, identify the packet that was not received correctly based on the order information of the packet received without transmission error, and from the transmitting station to the receiving station Packet transmitting means for transmitting the entire series of data from the transmitting station to the receiving station by packet transmission; and data output from the packet transmitting means based on order information output from the packet transmitting means. Is separated into data in a packet arriving at a receiving station with a delay due to retransmission or the like (hereinafter referred to as retransmission data) and data in a packet arriving in a correct order (hereinafter referred to as non-retransmission data). And a data transmission device. 2. Temporary storage means for temporarily storing non-retransmission data output by the data separation means; retransmission data output by the data separation means and order information on each retransmission data (each packet in a series of data) Retransmission data holding means for combining and holding the retransmission data output from the temporary storage means based on the order information output from the retransmission data holding means. 2. The data transmission device according to claim 1, further comprising: a data interpolation unit that interpolates with retransmission data output from the unit and reconstructs the series of data without error. 3. The data transmission apparatus according to claim 2, wherein the order information uses the number of octets from the beginning of the series of data to the beginning of the data in each packet and the number of octets of the data in each packet. 4. The data transmission apparatus according to claim 2, wherein the number of octets of data in each packet is fixed, and the sequence information uses a packet serial number sequentially allocated to each packet from the beginning of the series of data. 5. The data separating means has a serial number comparing function and a data output destination switching function, and the serial number comparing function is configured to transmit sequence information of a received packet and sequence information of a packet expected to be received next. If the order information of the received packet is the same as the order information of the packet expected to be received next, the data in the packet is regarded as non-retransmission data, and the output destination is set as the temporary storage means, If the order information of the received packet is older than the order information of the packet expected to be received next, the data in the packet is regarded as retransmission data, the output destination is set to the retransmission data holding unit, and the order of the packet is The information is output to the retransmission data holding means. If the order information of the received packet is newer than the order information of the packet expected to be received next, the packet The data in the packet is regarded as the non-retransmission data, the output destination is the temporary storage means, and the packet expected to be received from the next packet to the packet immediately before the received packet should be received. , As data expected to be retransmitted, and instructs only the order information to be output to the retransmission data holding means. The data output destination switching function outputs the data in the packet indicated by the serial number comparison function. Follow ahead,
4. The non-retransmission data is output to the temporary storage unit, and the retransmission data is output to the retransmission data holding unit.
Or the data transmission device according to 4. 6. The retransmission data holding means includes: a retransmission data holding memory for holding retransmission data; order information on each retransmission data; and a position (or an unreserved position) in the retransmission data holding memory where each retransmission data is held. A retransmission data list holding memory for holding a retransmission data list that combines information indicating that the reception is performed into one entry, and a serial number comparison function, wherein the serial number comparison function is output from the data separation unit. The order information on the retransmission data is compared with the order information on the retransmission data recorded in the latest entry in the retransmission data list. If the order information on the retransmission data output from the data separation unit is newer, the retransmission is performed. Is added as expected retransmission data to the retransmission data list, If an entry corresponding to the retransmission data output from the means already exists in the retransmission data list and the retransmission data has not been received, the retransmission data is held in the retransmission data holding memory, and the holding position is stored. 6. The data transmission apparatus according to claim 2, wherein the retransmission data is recorded in an entry to be transmitted, and otherwise, the retransmission data is discarded. 7. The data transmission according to claim 2, wherein the retransmission data holding unit outputs, after receiving the series of data, retransmission data and order information on each retransmission data collectively. apparatus. 8. The retransmission data holding means, when receiving the series of data and outputting the retransmission data and the order information relating to each retransmission data collectively, sets the retransmission data closer to the head in the series of data. 8. The data transmission device according to claim 7, wherein the data is output in order. 9. The retransmission data holding unit, when receiving the series of data and outputting the retransmission data and the order information relating to each retransmission data collectively, the retransmission data closer to the end in the series of data. 8. The data transmission device according to claim 7, wherein the data is output in order. 10. The retransmission data holding memory and the retransmission data list holding memory of the retransmission data holding means are composed of semiconductor memories having a small overhead at the time of random access, and each of the retransmission data holding memory and the retransmission data list holding memory has a transmission period of the series of data. 7. The data transmission apparatus according to claim 6, wherein retransmission data generated therein and an entry corresponding to each retransmission data are kept and output collectively at the end of transmission of the series of data. 11. The retransmission data holding memory, after the transmission of the series of data is completed, the retransmission data holding memory,
And retransmission data generated during the transmission period of the series of data collectively output from the retransmission data list holding memory, and an entry corresponding to each retransmission data, until output to the data interpolation unit, 11. The data transmission apparatus according to claim 10, further comprising a retransmission data temporarily stored and a retransmission data list temporary storage disk. 12. A packet is generated by dividing a series of data, adding order information indicating the context of the divided data, and adding an error detection code for detecting a transmission error to each of the divided data. The transmitting station sequentially transmits from the transmitting station to the receiving station via the transmission path, and the receiving station detects a transmission error using an error detection code in the received packet, and discards the packet when the transmission error is detected. Then, based on the order information of the packets received without transmission errors, the packets that were not received correctly are identified and retransmitted from the transmitting station to the receiving station, so that the entire series of data is transmitted from the transmitting station to the receiving station. Based on the order information held in the packet, the data in the packet transmitted and in which no transmission error was detected is the data in the packet that arrived at the receiving station after a delay due to retransmission or the like (hereinafter referred to as “data”). Below, retransmitted data) and other,
A method of outputting received data, wherein data is separated and output from data (hereinafter referred to as non-retransmission data) in a packet arriving in a correct order. 13. The non-retransmission data output according to the reception data output method according to claim 12 is temporarily stored while being separated from the retransmission data during the transmission period of the series of data, and the order of the retransmission data and each retransmission data is stored. The information (information indicating the position of the data in each packet in the series of data) is separately held in combination, and after the transmission of the series of data is completed, the order information on each retransmission data is processed in the processing of the series of data. A method of interpolating non-retransmission data with retransmission data and reconstructing the series of data without error on the basis of (1). 14. The received data temporary storage according to claim 13, wherein, as said order information, the number of octets from the beginning of said series of data to the beginning of data in each packet and the number of octets of data in each packet are used. Method. 15. The sequence information according to claim 13, wherein the number of octets of data in each packet is fixed as the order information, and the serial number assigned to each packet in order from the head of the series of data is used as the order information. Method for temporarily storing received data. 16. The sequence information of a received packet is compared with the sequence information of a packet expected to be received next. If the sequence information of the received packet is the same as the sequence information of the packet expected to be received next, If the data in the packet is regarded as non-retransmitted data and the sequence information of the received packet is older than the sequence information of the next packet to be received, the data in the packet is regarded as retransmitted data and the received packet is If the order information of the packet is newer than the order information of the packet that is expected to be received next, the data in the packet is regarded as non-retransmission data. 14. The method according to claim 13, wherein the packet to be received is data expected to be retransmitted. 17. The received data temporary storage method according to claim 16, wherein if the received retransmission data has already been received, the retransmission data is discarded. 18. Receiving the series of data, referring to retransmission data and order information related to each retransmission data in order from the data closest to the head in the series of data, and interpolating non-retransmission data with retransmission data. 14. The method according to claim 13, wherein the series of data is reconstructed without error. 19. Receiving the series of data, referring to retransmission data and order information on each retransmission data in order from the data closest to the end in the series of data, and interpolating non-retransmission data with retransmission data. 14. The method according to claim 13, wherein the series of data is reconstructed without error. 20. The reception data according to claim 13, wherein retransmission data generated during a transmission period of the series of data and order information relating to each retransmission data are stored in a semiconductor memory having a small overhead at the time of random access. Temporary storage method. 21. Retransmission data generated during the transmission of the series of data after the transmission of the series of data and the order information related to the retransmission data are transferred from a semiconductor memory with a small overhead at the time of random access. 21. The method for temporarily storing received data according to claim 20, wherein said method moves to a magnetic disk device. 22. A step of dividing a series of data, generating a packet by adding order information indicating the context of the divided data, and adding an error detection code for detecting a transmission error to each of the divided data. Transmitting the packet from a transmitting station to a receiving station via a transmission path; and transmitting the data included in the packet transmitted via the transmission path to the order information held in the packet. Separating the data in a packet that has arrived at the receiving station with a delay due to retransmission or the like (hereinafter referred to as retransmission data) and other data in the packet that has arrived in a correct order (hereinafter referred to as non-retransmission data). A first storing step of storing non-retransmitted data, a second storing step of storing retransmitted data separately from the non-retransmitted data, and a transmission end of the series of data. Outputting the non-retransmission data stored in the first storage step and the retransmission data stored in the second storage step in a correct order. .