JPH0534862B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to reduce the overhead during data transmission regarding a transmission data division method of a multi-layer protocol when transmitting data that exceeds the maximum transfer length of each layer protocol. data division specifying means for providing an instruction regarding division of transmission data, in which first information regarding the length, and second information regarding the maximum transfer data length and the data length added at each layer in each layer of a protocol consisting of a plurality of layers are introduced; Transmission data is introduced, data division means divides the transmission data according to instructions from the data division designation means, and transmission data divided by the data division means is introduced and processed based on a protocol consisting of multiple layers. and a protocol processing means for performing.

[Industrial application field]

The present invention relates to a transmission data division method for a multi-layer protocol, and particularly to a transmission data division method for a multi-layer protocol when transmitting data exceeding the maximum transfer length of each layer protocol.

[Conventional technology]

In recent years, open system interconnection (Open
Systems Interconnection (hereinafter referred to as OSI)
Hierarchization of communication procedures, as typified by reference models, is becoming common. Therefore, many communication control devices implement protocols of multiple layers within one communication control device.

The data units in each layer in such a communication control device are different, and when data is transferred between each layer, protocol control information is added. Therefore, it is necessary to divide data appropriately when transferring data between protocols.

FIG. 5 shows a conventional method of dividing transfer data. For example, for a protocol consisting of multiple layers, <
Focus is on the n> layer and the <n-1> layer.

In the figure, "transmission data" is from <n> layer to <
It shows data to be transferred to the <n-1> layer, and this transmission data becomes a protocol data unit ((n)-PDU) in the <n> layer.

When the <n-1> layer receives this (n)-PDU, it further adds protocol control information (protocol header) and transfers it to the lower layer as an (n-1)-PDU. However, this (n-1)-PDU is <n-
1> If the maximum data length in the layer is exceeded, the data is divided so as not to exceed the maximum data length.

For example, as shown in Figure 5, (n)-PDU is
Divide into three pieces of data a, b, and c. In addition to the transmission buffer that stores the (n)-PDU, two transmission buffers are prepared, and data a and data b are copied to these buffers. As a result, data a, b, and c were stored in each of the three transmission buffers, and a protocol head was added to each data as transfer data.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional method, the data length of the protocol data unit is checked every time data is transferred between each layer, and if the value exceeds a predetermined value, the data is copied or divided each time. Therefore, as the number of hierarchies increases, the copying and division processing requires more effort and overhead increases, which is a problem.

The present invention was created in view of these points, and an object of the present invention is to provide a transmission data division method for a multilayer protocol that reduces overhead during data transmission.

[Means to solve the problem]

FIG. 1 is a principle block diagram of a transmission data division method of a multi-layer protocol according to the present invention.

In the figure, data division instructing means 111 specifies the transmission data length in the first layer of a protocol consisting of multiple layers, and the first information 113 regarding the data length of the layer in each layer after the first layer. Second information 115 regarding the maximum transfer data length in each layer and the additional data length added in the layer is introduced for each layer, and when additional data is added to data in each layer, the maximum transfer data length in the layer If the length exceeds the additional data length, instruct division into pieces of data within the additional data length at the relevant layer.

The data division means 121 receives the transmission data, and in response to the instruction of each layer by the data division instruction means 111, the data division means 121 divides the data for each division instruction target data in the transmission data corresponding to the instruction of each layer. Perform division by adding additional data.

The transmission data divided by the data division means 121 is introduced into the protocol processing means 131, and the transmission data is processed based on the protocol consisting of the plurality of layers.

Therefore, as a whole, virtual division of the transmission data is performed for each layer based on the transmission data length, the maximum transfer data length of each layer, and the additional data length, and the transmission data is divided into each layer using the virtual division. It is configured so that it can be transmitted according to the protocol.

[Effect]

According to the present invention, the data division instruction means 111 performs virtual division processing for each layer of a protocol consisting of a plurality of layers. That is, in the first layer of the plurality of layers, an additional data length is added to the data in response to first information regarding the data length of the layer and second information regarding the maximum transfer data length of the first layer and its additional data length. If the additional data exceeds the maximum transfer data length of the layer when added, instructs to divide the data into pieces of data that are within the maximum transfer data length of the layer when the additional data is added in the layer. Then, the same virtual division process as that for the first layer is performed for subsequent layers as well.

After this temporary division processing, the data division means 12
1, for the introduced transmission data, in response to the instruction of each layer from the data division instruction means 111, the addition at each layer for each division instruction target data in the transmission data corresponding to the instruction of each layer; Generate data with added data.

The protocol processing means 131 performs transmission processing on the transmission data of the layer divided by the data division means 121 according to the protocol of the layer.

Since the transmission data to be transmitted according to the protocol of each layer is divided by the virtual division process as described above, when the transmission data is received by the data division means 121, the transmission data according to the protocol of the layer concerned is divided. It is in a split format,
The splitting does not require any actual data movement processing. Therefore, the burden (overhead) imposed on the movement process is significantly reduced.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows the configuration of an embodiment in which the multi-layer protocol transmission data division method of the present invention is applied.

Correspondence between the embodiment and FIG. 1 Here, the correspondence between the embodiment of the present invention and FIG. 1 will be shown.

The data division designating means 111 includes the bus control unit 2
It corresponds to 11.

The first information 113 corresponds to the transmission data length notified from the CPU 201 to the bus control unit 211.

The second information 115 is the protocol control unit 231
This corresponds to the maximum data length and header length of each layer of the protocol notified to the bus control unit 211 from.

The data dividing means 121 corresponds to the protocol control section 231.

The protocol processing means 131 corresponds to the protocol control section 231 and the transmission buffer 241.

Examples of the present invention will be described below assuming that the correspondence relationship as described above exists.

Configuration of the Embodiment In FIG. 2, a communication system to which the multi-layer protocol transmission data division method of the present invention is applied performs overall control and data processing.
A CPU 201, a memory 203 that stores data processed by the CPU 201, and a memory 203 that stores data processed by the CPU 201.
The communication control unit 210 transmits the processed data to another communication system (not shown) or receives data sent from another communication system.

The communication control unit 210 also includes a bus control unit 211 that controls data exchange with the CPU 201, a protocol control unit 231 that performs processing based on the protocol, and a physical bus control unit 231 that controls data exchange with the transmission path. Layer control section 233
and a transmission buffer 24 that temporarily stores data input and output between each component in the communication control unit 210.
1.

For example, consider the case where the OSI reference model is applied. The protocol control unit 231 performs control based on data link protocols, network protocols, and transport protocols.

Furthermore, the transmission buffer 241 physically consists of a plurality of buffers, and if the protocol data unit for each protocol exceeds the capacity of each buffer, one protocol data unit can be stored in two or more buffers. It becomes possible.

The CPU 201, the memory 203, and the bus control section 211 in the communication control section 210 are connected by a bus. The protocol control section 231 is connected to the bus control section 211 and the physical layer control section 233, and the physical layer control section 233 is further connected to the transmission path. Further, the transmission buffer 241 is shared by each component within the communication control section 210.

Operation of the embodiment Next, the operation of the embodiment of the present invention described above will be explained.

(i) Operation of bus control section FIG. 3 shows the operation procedure of the embodiment when focusing on the bus control section 211.

First, the CPU 201 notifies the bus control unit 211 of the transmission data length prior to data transmission. The bus control unit 211
The transmission data length sent from is received (step 311).

Next, the bus control unit 211 sends the protocol control unit 231 to each protocol layer (data link layer, network layer, and transport layer).
A request for notification of the protocol header length and maximum transfer data length is sent (step 312).

The protocol control unit 231 is the bus control unit 2
In response to the notification request from 11, the protocol header length and maximum transfer data length of each protocol layer are sent back to the bus control unit 211, and the bus control unit 211 receives these information (step 313).

Next, the bus control unit 211 performs step 311.
The transmission data length received in step 313
Based on the header length of each layer of the protocol and the maximum transfer data length received in step 314, the transmission data division method is determined. The maximum transfer data length for each layer of the protocol is known, and the header length of each layer that should be included in it is also known, so the divided transmission data can be determined so as not to exceed the maximum transfer data length for each layer of the protocol (details will be described later). .

Next, the bus control unit 211 controls the CPU 201
Receives transmission data from (step 315),
One of the divided units is sent to the protocol control section 231 (step 316).

The protocol control unit 231 first performs processing in the transport layer and adds a transport protocol header. Similarly, a base is added to each layer of the network layer and the data link layer. The data to which each header has been added is stored in the physical layer control unit 23
3 to the transmission path. Note that since the maximum transfer data length in each layer has been taken into consideration in advance, there is no need to copy or divide data at this point.

Next, the bus control unit 211 determines whether all data transmission has been completed (step 317). If negative judgment is made, step 315
Return to and repeat the process for another division unit.

If an affirmative determination is made in step 317, the data transmission operation ends.

(ii) Procedure for dividing transmission data FIG. 4 shows a specific procedure for dividing data in data transmission according to the embodiment.

For example, the communication control unit 2 is controlled by the CPU 201.
Let us consider a case where transmission data a, b, c, d, and e of the memory 203 to be supplied to the memory 203 are virtually divided as shown in FIG.

The bus control unit 211 receives the transmission data length sent from the CPU 201 and the protocol control unit 2.
Based on the header length of each layer and the maximum transfer data length sent from 31, the division method is determined (step 314 of ``(i) Operation of bus control unit'' described above).

Determining the division method does not mean actually dividing the data, but rather determining the header length of the transport layer, network layer, and data link layer of the transmission data in the memory 203 as shown in FIG. The length of the transmitted data part accommodated in each protocol data unit when generating the protocol data unit of the layer for each layer, so that the transmitted data part including (virtual division).

To explain this specifically, first, in the transport layer, there is a header of the transport protocol (hereinafter referred to as the T header). Processing is performed sequentially starting from the beginning of the transmission data to ensure that the transmission data portion including the transmission data does not exceed the maximum transfer data length of the transport protocol. For example, the fourth
As shown in the figure, when the transmission data parts a and b that constitute the transmission data are combined with the T header to form a transport layer protocol data unit,
If it is just the maximum transfer data length of the transport protocol, the length of the transmission data portions a, b for that protocol data unit is one result of virtual division of that protocol data unit. This result corresponds to one of the indications in the claims.

Furthermore, when the transmission data portions c and d that constitute the transmission data shown in Fig. 4 are combined with the T header of the transport protocol to form a unit of protocol data of the transport layer, the maximum transfer data length of the transport protocol is exactly equal to the maximum transfer data length of the transport protocol. The same applies to the transmission data portions a and b described above.

The same applies to the remaining transmission data portion e of the transmission data. It is assumed that the length of the transmission data portion e is shorter than the maximum transfer data length of the transport protocol.

The above-described virtual division provides the transport layer with an indication of the three transmission data parts that the three protocol data units constitute.

The result of this virtual division regarding the transport layer is held in the path control unit 211.

Next, the bus control unit 211 performs the same virtual division as described above for each of the three transmission data portions indicated by the virtual division as described above. First, transmission data parts a and b
(corresponding to the data length of the layer described in the claims) is combined with the network protocol header (hereinafter referred to as N header) to form the network layer protocol data unit. Although it exceeds the maximum transfer data length, if the sum of the data portion consisting of the T header and transmission data portion a and the N header is exactly the maximum transfer data length of the network protocol, then the length of the transmission data portion a is This is one result of virtual partitioning for the network layer. This result is one of the indications in the specification and claims of the present application.
corresponds to

Also, the combination of the transmission data portion b and the N header of the transmission data portions a and b is:
If it is exactly the maximum transfer data length of the network protocol or shorter than the maximum transfer data length of the network protocol, the length of the send data part b is equal to the virtual length of the network layer. This is one result of the division. This result corresponds to one of the indications in the claims.

Assuming that the same thing applies to transmission data parts c and d as for transmission data parts a and b, the result of virtual division for each is as follows.
Obtained in the same manner as described above. Transmission data part e
is the maximum transfer data length of the network protocol when combined with N headers, or
or shorter, the length of the transmitted data portion e is a result of a virtual partitioning for the network layer in question. This result corresponds to one of the indications in the claims.

The results of this virtual division regarding the network layer are held in the path control unit 211.

The virtual partitioning scheme described above is also used for the data link layer. In this data link layer, the transmission data part a, which is the result of virtual division in the network layer, is
(corresponding to the data length of the layer described in the claims), in addition to the N header and T header, when the header of the data link protocol (hereinafter referred to as the D header) is combined,
If the data length is the maximum transfer data length of the data link protocol or shorter than that, the virtual division process for the transmission data part a is not performed at the data link layer, but at the network layer. The result of the virtual division process at is used as the result of the virtual division process at the data link layer. If the same thing applies to each of transmission data portion b, transmission data portion c, transmission data portion d, and transmission data portion e, then the virtual division process as with transmission data portion a is performed at the data link layer. Instead, the result of virtual division processing at the network layer is used as the result of virtual division processing at the data link layer.

As described above, the transmission data a, b, c,
Virtual division processing for each layer regarding d and e is performed by the bus control unit 211.

After completing the virtual splitting process as described above,
The bus control unit 211 stores the transmission data a, b, c, d, and e stored in the memory 203 in individual buffers of the transmission buffer 241, and performs virtual division processing held as described above. The result is passed to the protocol control unit 231, and the protocol control unit 231 performs processing according to the protocol for each layer.

The transmission data a, b, c, d, e stored in the individual buffers of the bus control unit 211 described above are as follows:
Due to the above-mentioned virtual division processing, the data is stored in a format that has already been divided into protocol data units, so there is no need to move the data associated with the division of protocol data units after receiving the transmitted data as in the past. become. Therefore, the processing load (overhead) can be reduced by the time required for the movement process.

Summary of Embodiments In this way, the bus control unit 211
Based on the transmission data length sent from 01, the header length of each layer, and the maximum transfer data length sent from the protocol control unit 231, the transmission data is calculated assuming the final protocol data unit in the data link layer. Perform the division. The protocol control unit 231 processes each of the divided data.

Therefore, there is no need to copy or divide data during processing in the protocol control unit 231, and overhead during data transmission can be reduced.

Modifications of the invention In the embodiments of the invention described above,
Although the OSI reference model was considered, the present invention can be applied to anything that performs processing using a multi-layer protocol.

Furthermore, although the correspondence between the present invention and the examples has been explained in "Correspondence between the embodiments and FIG. 1", the present invention is not limited to this and there are various modifications. This can be easily deduced by those skilled in the art.

[Effects of the Invention] As described above, according to the present invention, transmission data is divided based on the transmission data length, the maximum transfer data length of each layer, and the additional data length of each layer,
By performing processing based on the protocol on the divided transmission data, the overhead during data transmission can be reduced, which is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a principle block diagram of the transmission data division method of the multi-layer protocol of the present invention, FIG. 2 is a block diagram of an embodiment to which the transmission data division method of the multi-layer protocol of the present invention is applied, and FIG. 3 is an implementation example. An explanatory diagram of the operation of the example, FIG. 4 is an explanatory diagram of the data division of the embodiment,
FIG. 5 is an explanatory diagram of a conventional example. In the figure, 111 is a data division specifying means;
13 is first information, 115 is second information, 121 is data division means, 131 is protocol processing means, 2
01 is a CPU, 203 is a memory, 210 is a communication control unit, 211 is a bus control unit, 231 is a protocol control unit, 233 is a physical layer control unit, and 241 is a transmission buffer.

Claims (1)

[Claims] 1 In the first layer of a protocol consisting of multiple layers, the transmission data length is transmitted, and in each layer after the first layer, the first information 113 regarding the data length of the layer, and the maximum data length in each layer. Second information 115 regarding the transfer data length and the additional data length added at the relevant layer is introduced for each layer, and if the additional data added to the data for each layer exceeds the maximum transfer data length of the layer. a data division instructing means 111 for instructing division into pieces of data that become data within the maximum transfer data length of the relevant layer when additional data is added in the relevant layer; a data dividing means 121 that performs division by adding the additional data in each layer to each division instruction target data in the transmission data corresponding to the instruction of each layer in response to a layer instruction; and the data dividing means 1. A transmission data division method for a multi-layer protocol, comprising: a protocol processing means 131 into which the transmission data divided by the multi-layer protocol 121 is introduced and performs processing based on the multi-layer protocol.