JPH0223749A - System for controlling transmission of transfer data - Google Patents

Abstract

PURPOSE:To reduce steps for obtaining a transfer schedule at the time of altering a window size by using a transmission window control table and controlling the transmission window size and the transmission available sequence number of recognition waiting transfer data. CONSTITUTION:A data transfer function 14 receives a data transmission request 1 from a user 11, assigning a sequence number at every data transfer unit, transmits 3 transfer data which can be transmitted for several minutes and holds transfer data having the sequence number beyond the window in the function 14. The alteration of the recognition command window is received in a flow control function 15 and the transmission window control table 13 is updated 4, whereby that the table 13 is updated 5 is informed to the function 14. When there is transfer data held in the function 14, transfer data which can be transmitted is transmitted for several minutes. When the function 14 cannot receive the recognition command with respect to transmitted transfer data within a specified time, a time out information 6 from a timer 12 is received in the function 14, is inquired to the table 13 and transfer data which can be re-transmitted is transmitted.

Description

[Detailed description of the invention] [Industrial application field] The present invention provides the maximum number of data (hereinafter referred to as "maximum data number") in communication control.

The present invention relates to transmission management of transfer data including retransmission when implementing a changeable flow control function (referred to as window size), and particularly to scheduling when the number of transfer data for retransmission exceeds the number of data currently receivable by one communication partner.

[Conventional technology]

Conventionally, a transmission management system for transfer data including this type of retransmission has had the configuration shown in FIG. Using Figure 4,
The flow of processing in the conventional technology is shown.

The data transfer function 52, which has accepted the data transmission request 41 from the user 51, assigns a sequence number to each data transfer unit and determines the range of sequence numbers that can be transmitted to the flow control function 53. A retransmission management area is established in the format shown in Figure 5, and transfer data that can be sent is chained there.
This retransmission management area is notified 43 to the retransmission function 54, and transmission 44 is performed. Further, transfer data having a sequence number outside the window range is held by the data transfer function 52.

When a timeout notification 45 is received from the timer 55, the retransmission function 54 retransmits the data in the retransmission management area shown in FIG.

[Problem to be solved by the invention]

However, in the conventional transfer data transmission management method that includes retransmission described above, transfer data waiting for confirmation is held in the retransmission management area, so if the window size can be changed, the transfer data is waiting for confirmation. When the window size is reduced and then a timeout is signaled,
The drawback is that data outside the window range is sent.

In addition, in order to correctly change the window size using the conventional method, the transfer data chain in the retransmission management area and the pending transfer data chain must be reset every time a window size change is notified. Since the data transmission function is aware of the window size change notification, there is a drawback that the number of processing steps increases.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, a technical object of the present invention is to provide a transfer data transmission management system that can realize a transfer schedule when two communicating parties change their window sizes with a small number of processing steps.

[Failure to solve the problem]

According to the present invention, the maximum number of data that can be received by one communication partner f (
window size).

By assigning a sequence number to the transferred data and transmitting data within the range that can be received by nine communication partners, and by receiving a confirmation command that includes the sequence number that the first communication partner should receive next, the second communication partner can currently receive the data. If the data sequence number is out of range, the retransmission means retransmits the transferred data and the communication partner changes the window size.

Transfer data characterized in that it has a transmission window management table that manages a transmission window size and a transmittable sequence number of transfer data waiting for confirmation, and performs scheduling of transfer data for retransmission based on this table. A transmission management method is obtained.

〔Example〕

Next, nine embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of this embodiment. FIG. 2 is used in this embodiment. FIG. 3 is a format diagram of a transmission window size management table. FIG. 3 shows an embodiment using the format diagram of the transmission window size management table shown in FIG.

First, using FIG. 1, the flow of a simple method for managing transmission of transfer data including retransmission when implementing a flow control function that allows the window size to be changed is shown. The data transfer function 14 accepts the data transmission request 1 from the user 11, assigns a sequence number to each data transfer unit, and arranges an empty window in the transmission window management table 13.2. Send as many transfer data as possible.3. Transfer data having a sequence number outside the window range is held by the data transfer function 14. The confirmation command window change is accepted by the flow control function 15, and the transmission window management table 13 is updated 4, and the update is notified 5 to the data transfer function 14, and the transfer data held by the data transfer function 14 is If there is, send 3 again for the number of transfer data that can be sent.

If the confirmation command for the transfer data sent by the data transfer function 14 is not received within a certain period of time, the data transfer function 14 accepts the timeout notification 6 from the timer 12, and the transfer data waiting for confirmation is stored in the transmission window management table 13. 2゜Send transfer data that can be retransmitted 3
do.

Next, the configuration of the transmission window management table 13 and the information to be managed will be shown using FIG. The transmission window management table 13 and a common management area 26 manage current window information.

(2) It is composed of entry groups 27 to 29 that manage sequence numbers corresponding to the window size. The confirmation-waiting-data header entry 21 holds an entry for managing the oldest sequence number of the transfer data waiting for confirmation according to the transmission method. The empty window head entry 24 holds an entry for managing the sequence number of transfer data to be transmitted secondary. The first unused window entry 22 holds an entry to be used next as a window. The next transmission sequence number 23 indicates the sequence number assigned to the transfer data to be transmitted the ninth time.

Next, in Figure 3, the actual transmission window management table 1
An example of window management using 3 is shown below.

When establishing a connection 31, first the common management area 26 and MA
An area of entries 27 to 29 corresponding to X window size is prepared, and each entry is cleared. The first entry 21 of data waiting for confirmation in the common management area 26 is set to 1 to indicate the first entry. Similarly, the empty window head entry 24 is set to 1.

The unused window first entry 22 is set to 7 to indicate the seventh entry when the window size is 6. The final entry 25 is the MAX window size, which is 15 in this example.

In the transmission window management table 13 at the time of data transmission 32 when the number of data transmission units accepted in the data transmission request 1 from the user 11 is 6, the sequence number of the transmission data is indicated by the empty line head entry 24. In this embodiment, entries are set in order from the first entry for the number of empty windows, and the empty window first entry 24 is changed to 7. Furthermore.

When the sequence number is issued from O, the secondary transmission sequence number 23 is 6. The transmission window management table 13 in the case where the window size reduction 33 is performed when the confirmation-waiting transfer data is unconfirmed is as follows.

When the new window size is 3, the empty window first entry 24 and the unused window first entry 22 are 4.
becomes. Further, the secondary transmission sequence number 23 is 3.

When retransmission 34 occurs due to timeout, there is no update to the transmission window management table 13, and the data transfer function 1
4 retransmits the transfer data from the confirmation waiting head entry 21 to the entry before the empty window head entry 24.

The transmission window management table 13 at the time of receiving the confirmation command 35 is included in the confirmation command. At this time, the next sequence number to be received is the confirmation waiting data first entry 2.
1 to 3. The unused window first entry 22 is set to 6. In this case, the first and second entries are treated as unused entries, and the window position is shifted. In this way, the entries for the window are shifted according to the update of the window size by the confirm command, and after reaching the final entry, it is used as a subsequent entry and from the first entry. In this example.

Due to the shift of the window position, an empty window is created within the window size, and sequence numbers 3 and 4 of the pending transfer data are sent, so the number changes from 35 when receiving the confirmation command to 36 when expanding the window size. Data transmission is started before moving, empty window first entry 24
becomes 6, and the primary transmission sequence number 23 becomes 5. The window management table 13 for transmission when the window size is expanded is 36.

When the new window size is 7, the unused window first entry 22 is set to 10. In this case, the empty window within the window size is enlarged and four new pieces of transfer data can be transmitted, but in this embodiment, only one piece of transfer data is pending.

Only this one piece of transfer data is sent.

〔Effect of the invention〕

As explained above, the present invention uses a transmission window management table to manage the transmission window size and transmittable sequence number of confirmation-waiting transfer data, so that confirmation commands are not received within a certain period of time. This has the advantage of being able to realize a transfer schedule with fewer processing steps when two communicating parties change the window size during retransmission of transferred data.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a format diagram of a transmission window management table used in the present invention, and FIG. 3 is an embodiment of the present invention based on FIG. 2. Figure 4 shows the overall configuration of the conventional method. FIG. 5 shows the format of the retransmission management area in the conventional system. In fig. 1...Data transmission request, 2...Window state adjustment, 3...Transfer data transmission including retransmission, 4...Update of transmission window management table, 5...Transmission window management table update notification, 6... timeout notification, 11... user, 12... timer, 13.
... Window management table for transmission, 14 ... Data transfer function, 15 ... Flow control function, 21 ... Confirmation waiting data first entry, 22 ... Unused window first entry, 23 ... Next transmission Sequence number, 24.
...Empty window first entry, 25...Last entry. 26...Common management area, 27-29...Sequence number management area, 31? -36... Transmission window management table update example, 41... Data transmission request, 42...
・Adjustment of transmission range, 43...Notification of retransmission management area, 4
4...Transmission of transfer data, 45...Timeout notification. 46...Retransmission, 51...User, 52...Data transfer function, 53...Flow control function, 54...Retransmission function. 55...Timer. Xiongdan day rXνhkD 娑解卯目

Claims (1)

[Claims] (1) In addition to managing the maximum number of data that can be received by the communication partner, a sequence number is assigned to the transferred data, data within the range that the communication partner can receive is transmitted, and the sequence number that the communication partner should receive next a flow control means for managing a range of sequence numbers of data currently receivable by a communication partner by receiving a confirmation command including a confirmation command; a retransmission means for retransmitting the transferred data, and a transmission window management for managing the maximum number of data to be transmitted and the sequence number of the transferred data waiting for confirmation when the communication partner changes the maximum number of receivable data. 1. A transfer data transmission management method, comprising a table, and facilitating rescheduling of transfer data for retransmission.