JPH02149151A - Buffer division method for inter-layer data transfer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding a buffer division method for data transfer between layers of an information processing system with a layered protocol, an object of the present invention is to reduce the number of buffer views acquired during data division and to reduce the frequency of use of the buffer. The purpose of this is to provide a buffer division method that allows for buffer division, and the division processing unit, which is activated when buffer division occurs by adding a header when transferring data from an upper layer to a lower layer, acquires a new buffer area when activated. a buffer acquisition means, a header copying means for copying a header into the acquired area, a new header data setting means for setting a dividing position of a divided buffer in the data area start pointer part in the copied header, and a header copying means for copying a header into the acquired area; and original header data setting means for setting the head position of the acquired buffer in the vanofa pointer section.

[Industrial Field of Application] The present invention relates to a buffer division method for data transfer between layers of an information processing system in which a protocol is layered.

In recent years, O3 has been standardized by l5O (International Organization for Standardization).
! Research on information processing systems equipped with communication control functions that comply with the Open System Interconnection (Open System Interconnection) standard is being widely conducted.

In the O3I reference model, the communication functions of an open system are layered into seven functional modules, and each functional layer is called a protocol layer. When communicating using such O3I standards, data is exchanged (transferred) in units of data between each layer of multiple layers. When sending data from an upper layer to a lower layer, a header is added to the data, and conversely, when sending data from a lower layer to an upper layer, the data included in the data sent from the lower layer is Removed headers. Actual transfer is performed by outputting the head pointer of the transfer data (header section and data section are linked) stored in the memory buffer to the transfer destination layer.

On the other hand, the data unit to be communicated has a fixed capacity (length), and when sending data from an upper layer to a lower layer of O3I, adding a header may overflow the capacity of the data unit. Therefore, the exchange of data between the nine layers, which requires dividing data to form multiple data units, is performed by buffers as described above, and dividing data means dividing the buffer. . However, the conventional method has problems such as a large amount of memory capacity being occupied due to buffer division, and an improvement is desired.

[Prior Art] FIG. 7 is an explanatory diagram of data transferred between layered protocols.

In the case of FIG. 7, three layers are shown: the N+1 layer, the N[, and the N-1 layer. In fact, in the O3I standard model, the layers are in order from lower to upper: physical layer, data link layer,
Seven layers are defined: network layer, transport layer, session layer, presentation layer, and application layer, and layer N in Figure 7 is any layer other than the top and bottom of these seven layers. It can be passed.

In FIG. 7, when data is transferred from the N+1 layer to the N layer, a header (
or PCI: protocol control information) is added and transferred to the N layer.

The N layer receives the entire header sent from N+1 as N layer data, and further sends this data to N-1.
When transferring to layer N-11, a new header created in layer N is added and transferred to layer N-11.

When data is transferred from an upper layer to a lower layer in this manner, a new header is added to the original data portion, resulting in a longer data length. In FIG. 7, when data is transferred from a lower level to an upper level, the headers are sequentially removed, so the data length becomes shorter.

Specifically, the above data transfer is performed using a memory buffer, and when there is insufficient area for transfer, a buffer area is acquired, and when it is no longer needed, the area is discarded.

Traditionally, in data transfer between protocols, one data unit transferred has a fixed length (or capacity).
stipulated in However, when data is transferred from an upper layer to a lower layer as described above, the length of the data unit exceeds the specified length due to the addition of a header.

FIG. 8 is an explanatory diagram of conventional buffer division, which is performed when a specified data length is exceeded during transfer.

In the case of Figure 8, when transferring data (PDU) of N+11, which is the specified data length, to NJW, the header (Pct)
By adding , the specified data length will be exceeded. In that case, N+1 data is al! : part b (a+
b=N+1 layer PDU). A header (Pct) is added to each of the divided data a and data b. In this way, as shown in (1) and (2) in Figure 8,
Two sets of data units are formed.

FIG. 9 shows an explanatory diagram of a conventional data division operation.

In A of FIG. 9, when the data part '93 in the N+1 layer stored in the memory buffer is transferred to the N layer, a header part 92 is added. Note that the header section is usually provided as an identifier of the data section in which actual data is stored.

However, if the header section 92 is combined with the data section 93, the length of the specified data unit will be exceeded, so the data section 93 will exceed the length of the specified data unit.
3 will be divided into a and b.

In this case, the length of the header and the length of data a become the specified data unit length.

Therefore, as shown in FIG. 9B, a data section 94 containing only data a is combined with a header section 92 to form one data unit. Then, the header part 92 is copied to the newly acquired buffer area 95, a new header part is provided, and the newly acquired buffer area 95 is
By copying the data b of the data section 94 to 6 and providing a new data section, another divided data unit is constructed.

[Problems to be Solved by the Invention] As described above, when a buffer is divided during data transfer between layers, it is necessary to acquire a buffer area not only for the header area but also for the data area. However,
Since the buffer uses a finite capacity of memory, if the buffer is divided frequently, the total amount of the buffer is constant, so a buffer shortage condition occurs due to an increase in the number of buffers lent. When this buffer shortage occurs, retries are performed until a buffer can be acquired, so it takes time to acquire the buffer, and the processing device is wasted for this purpose, resulting in a decrease in processing efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a buffer division method that can reduce the amount of buffer acquired during data division and reduce the frequency of use of the buffer.

[Means to solve the problem] FIG. 1 is a diagram showing the basic configuration of the present invention.

10 in FIG. 1 is a division processing unit, 11 is a buffer acquisition means,
I2 represents a header copying means, 13 a new header data setting means, 14 an original header data setting means, 15 a memory, 153 and 155 in the memory a header section, and 154 a data section.

The present invention provides a storage area in the header for data indicating the number of divided buffers and the position of the divided buffers (division counter and divided buffer pointer), and when division occurs, no new buffer is acquired for the data section. Then, only the buffer for the header part of the data after division is acquired, and only the pointer value pointing to the data part stored in the header part is used to indicate the division position.

[Operation] When transferring the contents of the N(1) data section 154 with the protocol stored in the buffer to the lower layer, the header section 15
Add 3. However, since the data length (combined length of the header and data) exceeds the specified unit length, division occurs in the data section 154.

When division occurs, the division processing unit 10 is activated, and first, the buffer acquisition means 11 of the division processing unit 10 acquires a new buffer for the header.
55 is acquired, the header copying means 12 copies the contents of the header section (referred to as the original header section) 153 to the buffer 155, thereby forming a new header section in the buffer 155.

When the copying is completed, the new header data setting means 13 sets part of the data stored in the new header of the buffer 155. That is, the division position of the data section 154 (the beginning position of b of the buffer 154) is set as the head pointer of the data area indicated by the new header.

Next, the original header part 15 is sent to the original by the fern data setting means 14.
The divided buffer pointer (provided according to the present invention), which is the data in 3, is set to a value representing the starting position of the new header section 155.

Embodiment] FIG. 2 is a processing flow diagram of the embodiment, FIG. 3 is a header configuration diagram of the embodiment, and FIG. 4 is a diagram showing an example of an information processing system in which the present invention is implemented.

In the information processing system shown in FIG. 4, a memory 41 is connected to a CPLI (central processing unit) 40, and data is transferred to and from each input/output device via an interface 42, 45 connected to a bus and a line adapter 4B. The 0-line adabuk 48 is connected to a communication line by a modem 49 and communicates with the other party's information processing system in accordance with the O3I standard. The communication function of the upper layer of the protocol is executed in the CPU 40 and the buffer in the memory Using the area,
Data transfer between 111 and 111 is performed.

To explain the header configuration diagram of the embodiment shown in FIG. 3, a pointer 30 to the next buffer in the header section indicates the position of the header of the next succeeding data, and a data area start pointer 31 indicates the source of this header. The head pointer of the data section is stored, the buffer length 32 represents the actual length of the buffer to be used, the data length 33 is the data length of the data section, the pool identifier 34 is the identifier of the application that uses the buffer, and the receive flow The control management data 35 and the pointer 38 to the user buffer are used for other purposes. New data provided by the present invention is a division counter 36 and a pointer 37 to the division buffer.

What is stored in the division counter 36 is the number of headers newly generated when division occurs, and the pointer 37 to the division buffer stores the number of headers that are newly generated when division occurs, and the pointer 37 to the division buffer stores the number of headers that are newly generated when division occurs, and the pointer 37 to the division buffer stores the number of headers that are newly generated when division occurs. The starting position is set.

The processing flow shown in FIG. 2 will be described. In this embodiment, the processing flow shown in FIG. 2 is executed using the CPU 40 and the buffer of the memory 41 shown in FIG.

Determine whether or not division has occurred in the data section buffer during data transfer processing to the lower layer (step 20).
. When a split occurs, a buffer is acquired (step 2).
1) Next, copy the contents of the buffer header before division into the acquired buffer (step 22). After this, copy the data area start pointer value (31 in Figure 3) and data length (33 in Figure 3). New settings are made (step 23).

Next, the pointer value to the next buffer in the header section before division (FIG. 3, 30) is set to O (step 24).

Through the above processing flow, data to be transferred to the lower layer is formed on the buffer, and the data is transferred to the lower layer.

FIG. 5 is a diagram showing the state after buffer division according to the present invention;
FIG. 6 is a diagram showing the relationship between the header section and the data section after division.

The state shown in FIG. 5 represents a state in which when the header section 52 is added to transfer the data section 53 in the buffer, division occurs in the buffer of the data section 53 and a buffer 54 is acquired. Buffer division occurs at the boundary between a and b within the data section 53.

As a result of the division in FIG. 5, the relationship between the header sections 52, 54 and the data section 53 is shown in FIG.

The relationships between the buffers are established using the division counter area and the area of the pointer to the division buffer provided in the header according to the present invention, as described with reference to FIG.

That is, the data area start pointer of the header section (original header section) 52 in FIG. 6 indicates the start of the data area in the data section 53, and the data length of the line below it indicates the length of the data area a. In this case, the division counter of the original header section 52 is set to "1", and the division buffer is 1.
Show that there is one thing. The starting position (address) of the header section (new header section) 54 acquired by the division is set in the area of the pointer to the divided buffer that follows this.

Next, the data area start pointer in the new header section 54 has the following information:
The division position of the divided data portion 53 is set, and the data length is set to b.

[Effects of the Invention] According to the present invention, even if buffer division occurs, there is no need to acquire a buffer for the data section as in the conventional case, and only the buffer for the header section needs to be acquired, so the amount of buffer usage can be reduced. Since buffer shortage can be prevented from occurring, processing efficiency can be improved. Also,
Conventionally, data was copied when acquiring a data section buffer, but since data copying can be eliminated, processing performance can be improved by eliminating buffer acquisition and copying time.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic configuration of the present invention, Fig. 2 is a processing flow diagram of an embodiment, Fig. 3 is a diagram of a hardware configuration of an embodiment, and Fig. 4 is an example of an information processing system in which the present invention is implemented. Figure 5 showing
The figure shows the state after buffer division, Figure 6 shows the relationship between the header section and data section after division, Figure 7 is an explanatory diagram of transfer data between layered protocols, and Figure 8 shows the conventional FIG. 9 is an explanatory diagram of a conventional data division operation. In FIG. 1, 10: Division processing unit 11: Buffer acquisition means 12: Header copying means 13; New header data setting means 14; Original header data setting means 15: Memory Patent applicant Kazuo Hosaka, Patent attorney, Pfn Co., Ltd. ζ bubble 5a moon power ""Lm" +1-ru・1 compensation death mo P-system's tide IJX ■ figure 4 item 1'!, %IrearotokoIuliilω weakens, Cheetag i prevents υ month figure' ?) 7 countries

Claims (1)

[Claims] In a buffer division method for inter-layer data transfer in an information processing system with a layered protocol, the method is activated when buffer division occurs by adding a header during data transfer from an upper layer to a lower layer. The division processing unit (10) includes a buffer acquisition unit (11) that acquires a new buffer area upon startup, and a header copy unit (12) that copies a header to the acquired area.
), new header data setting means (13) for setting the division position of the divided buffer in the data area head pointer part in the copied header, and setting the head position of the acquired buffer in the divided buffer pointer part in the original header. Original header data setting means (14
) A buffer division method in interlayer data transfer, characterized by comprising: