JP3282395B2 - Data transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission apparatus, and more particularly, to a plurality of frame lengths (L) and a plurality of maximum outstanding I frames (K) (hereinafter referred to as "K") in a data link layer of an OSI reference model. Outstanding Number (K) ”).

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. 3-145242 discloses a proposal for improving the memory use efficiency of a data terminal device having a protocol stack conforming to the OSI reference model. In short, this gazette discloses a technology relating to data construction of data terminals in the G4 protocol. Specifically, it is as follows.

In transmitting image information data, when a document is read by a scanner at Layer 7 and encoded and stored in the image information storage device, the image information data stored in the image information storage device is stored at Layer 6 by one. The CDUI frame is cut out in units of blocks, and a CDUI frame is formed by using an area in which each task of the layer 6 is uniquely allocated to save transmission control data and the like. Next, the layer 6 requests the OS (operation system) for block allocation. The OS notifies the layer 6 of an empty table from a common area management table for managing an area (shared memory area) in which communication data and the like commonly accessed by the respective tasks are stored (shared memory area). The layer 6 sequentially stores the data of the CDUI frame in the notified block, sets the number of bytes of the CDUI frame to the size of the valid data, and sets the release enable flag. Then, the layer 6 notifies the layer 5 that there is transmission data, and notifies the layer number of the common area management table corresponding to the block storing the data of the CDUI frame, and makes a transmission request.

[0004] In layer 5, data is read from the notified block, and a data is written in the same block with a layer 5 header added. The size of the effective data and the task identification information are also rewritten. Then, layer 5 issues a transmission request to layer 4 in the same manner. This is repeated for each layer to construct final data.

When transmitting transmission control data, the OS is commonly accessed by each task in an area in which each task is uniquely used for storing transmission control data and the like. A management table similar to the common area management table formed in an area where communication data and the like is stored, and a plurality of blocks having a size corresponding to the maximum capacity of communication data and a block having a capacity corresponding to the size of transmission control data similar to the maximum size of communication data are formed. I do. For example, in the layer 6, the CDCL is created in an empty block of an area allocated to be used independently by each task for saving transmission control data and the like. The task identification information and the size of the valid data are set in the corresponding management table, and the releasable flag is reset. In this state, the layer 6 notifies the layer 5 of the table address information of the management table (transmission request), reads out the data from the notified address information and adds the layer 5 header in the same manner as the processing of the image information data. Write to the same block. This is repeated for each layer to construct final data.

[0006] Thus, Japanese Patent Application Laid-Open No. 3-145242 is disclosed.
In the invention described in the above item, the size of the transmission control data is smaller than the size of the transmission data, and it is noted that it is not efficient to apply the same memory management method equally to the size of the transmission data. By using differently sized blocks, transmission control data having a smaller data size is stored, and the efficiency of use of the memory is improved.

[0007]

However, in the invention described in Japanese Patent Application Laid-Open No. 3-145242, no measures are taken against the case where the size of the transmission data itself fluctuates.

That is, the frame size of the transmission data is 2K
Since the same transmission buffer is used regardless of whether it is equivalent to Octet or 128 octets, there is a disadvantage that when the protocol is equivalent to 128 octets, only about 6% of one transmission buffer is used. is there.

Also, recent revisions of the standard relating to G4 (J
Due to T-T90), the outstanding number (K) of the data link layer is greatly increased as shown in the following table.

[0010]

[Table 1]

Conventionally, K = 7, and the above-mentioned disadvantage has not been regarded as a serious problem. However, when K = 80, the memory secured as a data link transmission buffer becomes enormous. It becomes a big problem.

Further, if it is predicted that the modulo will be expanded in the future, it will be a problem to be solved immediately.

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and has as its object to provide a data transmission apparatus capable of improving the use efficiency of a memory even when the size of transmission data itself varies. It is in.

[0014]

According to the first aspect of the present invention,
What is claimed is: 1. A data transmission device which implements a protocol defined to use a plurality of sizes of frame lengths (L) and a plurality of outstanding numbers (K) in a data link layer of an OSI reference model, wherein said storage means stores transmission data. The data storage area is divided into blocks corresponding to the maximum frame length (L _MAX ) as an initial state, and 1 is added to the management table.
First means for making a one-to-one correspondence, management means for managing the blocked data storage area using the management table group as an empty memory queue, used memory queue management means for each frame size, and unused memory queue management Means, and second means for, during transmission, subdividing one block into blocks of a size suitable for the required memory size using the management means, the used memory queue management means and the unused memory queue management means; Having.

According to a second aspect of the present invention, in the data transmission apparatus of the first aspect, when the frame size is determined by a protocol, the management unit, the in-use memory queue management unit, and the unused memory queue management unit are used. Third means for dividing one block into blocks of a size suitable for the frame size and reconstructing the memory as an initial state.

According to a third aspect of the present invention, in the data transmission apparatus according to the first aspect, further comprising a fourth means for returning the block to an initial state when all the blocks in use by being subdivided are released.

According to a fourth aspect of the present invention, in the data transmission apparatus of the first aspect, after the sub-division has been completed, the waiting state is maintained for a preset time when all the blocks in use are released, and There is further provided fifth means for returning the block to the initial state.

According to a fifth aspect of the present invention, in the data transmission apparatus according to the first aspect, a counter for counting the number of usable or unusable memories for each frame size, and a counter value for the counter when the memory is used. Sixth means for increasing / decreasing when the memory is released, seventh means for notifying the protocol control function unit of a reception disabled state when the count value of the counter reaches a first specified value, and memory for releasing the count value of the counter. Eighth means for notifying the protocol control function unit of the reception enabled state when the second specified value is reached.

According to a sixth aspect of the present invention, a plurality of frame lengths (L) are provided in the data link layer of the OSI reference model.
And a data transmission device that implements a protocol defined to use a plurality of standing numbers (K), a storage means for storing transmission data, and said data corresponding to a maximum frame length (L _MAX ) as an initial state. 1st block of storage area and one-to-one correspondence with management table
Means for managing the blocked data storage area using the management table group as a free memory queue, used memory queue management means for each frame size, and unused memory queue management means. When the frame size is smaller than a specified value, the management unit;
Ninth means for newly securing a table for managing the remaining area using the in-use memory queue management means and the unused memory queue management means.

[0020]

According to the data transmission device of the first aspect, the first
The data storage area is divided into blocks corresponding to the maximum frame length (L _MAX ) as an initial state by means, and is associated with the management table on a one-to-one basis.

The management means manages the blocked data storage area using the management table group as an empty memory queue.

At the time of transmission, the second means re-divides one block into blocks having a size suitable for the required memory size by using the managing means, the used memory queue managing means and the unused memory queue managing means.

According to this, the memory management suitable for the frame size of the transmission data can be performed.

According to the data transmission apparatus of the second aspect,
As in the case of the first aspect, the data storage area is divided into blocks corresponding to the maximum frame length (L _MAX ) as an initial state by the first means, and the data storage area is associated with the management table on a one-to-one basis.
The management unit manages the data storage area that is blocked by using the management table group as a free memory queue.

When the frame size is determined by the protocol at the time of line connection, the third means uses one of the management means, the used memory queue management means and the unused memory queue management means to make one block suitable for the frame size. The memory is reconfigured as an initial state by dividing into blocks of a size.

According to the data transmission device of the third aspect,
In the seventh means, when all blocks in use by being subdivided are released, the blocks are returned to the initial state.

According to the data transmission device of the fourth aspect,
In the eighth means, when all the blocks in use by being subdivided are released, the waiting state is maintained for a preset time, and then the block is returned to the initial state.

According to the data transmission device of the fifth aspect,
The counter counts the number of usable or unusable memories for each frame size, and the sixth means increases or decreases the count value of the counter when the memory is used and when the memory is released.
As an example, when the number of available memories is counted by the counter, the sixth means may be configured to decrement the count value of the counter when the memory is used, and to increment when the memory is released.

The count value of the counter is equal to the first value.
When the number of usable memories becomes equal to or less than the first specified value, the seventh means notifies the protocol control function unit of the reception disabled state. As a result, the protocol control function unit stops the data flow.

On the other hand, when the memory is released and the count value of the counter reaches the second specified value, in other words, when the number of available memories increases to the second specified value, the eighth means causes the protocol control function unit to Notify the receivable state. As a result, the protocol control function unit restarts the data flow.

According to the data transmission device of the sixth aspect,
As in the case of the first aspect, the data storage area is divided into blocks corresponding to the maximum frame length (L _MAX ) as an initial state by the first means, and the data storage area is associated with the management table on a one-to-one basis.
The management unit manages the data storage area that is blocked by using the management table group as a free memory queue.

If the actually received frame size is smaller than the specified value at the time of reception, the ninth means manages the remaining area using the management means, the used memory queue management means and the unused memory queue management means. Secure a new table.

[0033]

【Example】

<< First Embodiment >> An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows the entire configuration of a facsimile apparatus as a data transmission apparatus according to one embodiment. The facsimile apparatus 10 includes a system control unit 12, a ROM 14, a RAM 16, an operation display device 18, a reading device 20, a printing device 22, an image processing device 24, an image storage device 26, a digital communication control unit 28, an analog communication control unit 30, A line switching control device 32 and a digital network control device 34 are provided.

Each of the above components except the system control unit 12 is connected to the system control unit 12 via a system bus 36.

The system control unit 12 is a processor that manages the flow of jobs in each of the above-described components to control the entire apparatus.

The ROM 14 is a program ROM in which a main control program for controlling the entire facsimile machine 10 and other data are stored. The RAM 16 is a memory functioning as a work area used by the system control unit 12.

The operation display device 18 includes a key panel (not shown) provided with a plurality of keys for the operator to input various instructions, and a display means such as an LCD display (not shown) for displaying various instructions to the operator. It is configured.

The reading device 20 is an image reading means such as a color / monochrome scanner for converting a transmission original into a read image signal and outputting the read image signal.

The printing device 22 prints out received images and the like on recording paper, and is composed of, for example, a high-speed printer such as an ink jet printer or a laser printer.

The image processing device 24 encodes transmission image information, decodes reception image information, and converts resolution, enlargement /
This is a hardware module that performs image processing such as reduction.

The image storage device 26 is a memory having a larger capacity than a so-called page memory, and has an image memory area, a code memory area, and other areas.

The digital communication control unit 28 includes a CPU, an RO
M, RAM (both not shown), etc., a digital network (for example, ISD
N network) (for example, G4 facsimile communication)
Is a functional unit that controls

The analog communication control unit 30 is a functional unit for controlling communication (for example, G3 facsimile communication) suitable for an analog network.

The line switching controller 32 includes a plurality of external line interfaces (in this embodiment, the digital network controller 3
4 and two of the later-described analog network controllers 40) and a plurality of internal communication circuits (in this embodiment, the digital communication controller 28).
And an analog communication control unit 30).
The line switching control device 32 includes the digital communication control unit 2
8 and connected to the analog communication control unit 30 via a modem 38 described later.

The modem 38 is a modulation / demodulation device for modulating and demodulating analog communication data. In this embodiment, the modem 38 has a low-speed mode function and a high-speed mode function.

The digital network controller 34 is a hardware module for interfacing a digital network such as an ISDN network with the facsimile machine 10.

The analog network controller 40 is a hardware module for interfacing the analog public network with the facsimile machine 10, and in this embodiment, has an automatic transmission / reception function.

The facsimile apparatus 10 thus configured performs G4 facsimile communication with a destination terminal apparatus connected via a digital network such as an ISDN network in the following manner. Do.

<< During Transmission >> The document file stored in the image storage device 26 is transferred to the digital communication control unit 28 by the system control unit 12 based on a transmission instruction from the operator. After the line connection, if there is a difference in characteristics between the terminal device and the destination terminal device (terminal device on the receiving side), the system control unit 12
Then, processing such as resolution conversion / enlargement / reduction is performed using the image processing device 24.

In the digital communication control unit 28, only the image information data is stored in an R (not shown) in the digital communication control unit 28.
The data is stored in a transmission buffer including a predetermined area of the AM. OS
All protocol data (including a header added to transmission information) of each layer based on the I reference model is stored in a shared memory (not shown in the digital communication control unit 28) managed by the OS of the digital communication control unit 28. (Composed of a part of the RAM).

Data link layer (layer 2) to be described later
The protocol control function unit reads data from the transmission buffer and / or the shared memory based on an instruction from the protocol control function unit of the upper layer, creates a transmission frame, and sends it to the transmission circuit to transmit it to the transmission path. I do.

<< Receiving >> The frame received from the transmission path is stored in the transmission buffer by the layer 2 protocol control function unit. Each layer protocol control function unit based on the OSI reference model processes the data in the transmission buffer, and finally extracts only the image information data and sends it to the image storage device 26. This data is filed and managed in document units.

Here, when data transmission apparatuses such as the facsimile apparatus 10 are connected to each other via the ISDN network, communication procedures performed between the calling apparatus, the ISDN network, and the called apparatus ( The communication protocol will be described with reference to FIG.

First, a call setup by the network is started by sending out a SETUP (call setup request) message from the calling side, and CALL PROC having a meaning of completion of call setup acceptance.
When a call on the called side is started after the transfer of (Call Proceeding: notification of processing start for call setting), an ALERT (Alerting: notification that the called side is calling) is generated, although not shown. Sent to the calling party. Next, when the called party responds, CONN (connet: notification that the called party has responded)
The message is sent to the calling side, and upon receiving this message, the calling side sends a CONN ACK (Connect Acknowledge: CON).
N) message is sent to the called side, and when the response is confirmed, an information channel (B channel) for data transmission is established between the calling side and the called side, and communication starts.

Next, the XID (Exchan
ge Identifier: Identifier exchange) Frames are exchanged, layer 2 such as modulo and outstanding number (K)
A preliminary adjustment (negotiation) is performed on the parameters.

Next, the calling side issues a command SABM (Set) to activate the setting of the logical link in the multi-frame mode.
Asynchronous Balanced Mode) or SABME (Set As
(Synchronous Balanced Mode Extended) is transmitted to start layer 2 on the called side. Here, SABM indicates the basic mode (modulo 8), and SABME indicates the extended mode (modulo 128).

A command UA (Unnumbered Ack) is sent from the called side.
When receiving the nowledge (unnumbered confirmation) and confirming the establishment of layer 2 (establishment of the logical link) (adjustment of the procedure class), the calling side transmits the signal SQ to extend the layer 3 end-to-end. Is transmitted, and the called party responds with the signal SF when accepting it.

When the layer 3 is established in this way, the calling side sends a CR (Call Request: logical connection setting request) message, and the called side responds to the CC.
(Call Connected: Logical connection setting confirmation) Reply message. This is for negotiating the modulo of layer 3 with the restart packet and the packet size and the like with the outgoing packet.

When layer 3 is established and a logical connection is set in this way, the calling side sends a block TCR to request a layer 4 connection, and the called side accepts the block TCR. Respond with block TCA (adjust block size).

When the layer 4 is established, the calling side sends a command CSS to instruct the start of the layer 5, and the called side responds with a response RSSP when accepting the command (window size). Adjustment).

When the layer 5 is established, the calling side sends a command CDCL to notify the terminal capability to be used in the document layer, and the called side sends a response RDCLP if the function can be used. To respond.

When the setting of the transmission function is completed in this way, the calling side sends a command CDS to notify the start of document transmission, cuts out transmission data (image information data) in block units, Frame C
Send by DUI.

The transmission of the transmission data by the frame CDUI is performed while exchanging a predetermined signal for each page.

When the transmission of the image information has been completed in this way, the calling side transmits the command CSE, although not shown in the figure.
To notify the end of layer 5, and the called side responds with a response RSEP when accepting it.

Thereafter, when Layer 4 and Layer 3 are normally terminated in succession by sending a command from the calling side and responding to the response from the called side, the calling side sends a DISC (DiC) to ISDN.
sconnect: call release request) message is sent, which triggers the disconnection of the channel and the release of the call number.
(Release: Channel disconnection completion notification and call number release request)
The message is sent back.

Upon receipt of the REL message, the call number of the calling side is also released, and the REL COMP (Release Comple
te: Channel release and call number release notification) are sent to indicate release completion. This completes the release of the call.

FIG. 3 shows a configuration relating to control at the time of data transmission in the facsimile apparatus 10 as described above.
It is shown as a functional block diagram focusing on software.

In FIG. 3, the line control device 4
2, file 44, transmission buffer 4 as storage means
6. First in first out transmission data buffer (TxFI
FO) 47 and shared memory 49 for protocol data
The other parts represent software as functional blocks. In FIG. 3, thick solid arrows indicate the flow of transmission data, thin solid arrows indicate the flow of control signals, and dotted arrows indicate the flow of protocol data.

In FIG. 3, the system control function unit 4
8. Communication control function unit 50 and file control function unit 54
1 is a block diagram showing the main functions of the system control unit 12 shown in FIG. 1 described above. In practice, the functions of these function units are performed by the system control unit 12 according to a program stored in the ROM 16. It is realized by doing.

Device control function section 52, data reference information control function section 56, transmission buffer (BF) control function section 5
8, and layer 2 protocol control function units to layer 7 protocol control function units 60, 62, 64, 66, 68, 70
Is realized by the CPU in the digital communication control unit 28 executing a program (including hierarchical transmission control software) stored in the ROM in the digital communication control unit 28. It is a block representation of various functions.

The line control function unit 72 includes the system control unit 1
2 is a block diagram showing a line control function realized by a part of the functions of the digital network controller 34 and the function of the digital network controller 34.

The line control device 42 is a device related to the line control constituting the digital network controller 34.

The file 44 is stored in the image storage device 2 described above.
6, a transmission buffer 46, a transmission data buffer (TxFIFO) 47, and a shared memory 49 indicate a partial area of a RAM (not shown) in the digital communication control unit 28.

In the transmission buffer 46, a number of buffer areas are provided. These buffer areas are managed by the transmission buffer (BF) control function unit 58. The management of the buffer area will be described later in detail.

Here, the operation when transmitting the transmission data to the line will be described with reference to FIG. Here, it is assumed that a process such as resolution conversion is unnecessary for simplification.

First, based on an instruction from an operator or the like, the system control function unit 48 activates the communication control function unit 50 and instructs communication start. Thereby, the communication control function unit 50 instructs the line control function unit 72 to connect a line suitable for the communication according to the communication mode.

Next, upon confirming the line connection, the communication control function unit 50 activates the protocol control function units 60 to 70 to start G4 communication, and instructs the start of communication.

When the negotiation based on the protocol is completed, the communication control function unit 50
, And instructs the layer 7 protocol control function unit 70 to receive the data.
Thereby, the transmission data is transferred from the file 44 via the DPRAM (not shown) to the protocol control function units 60 to 70.
Is transmitted to the transmission data buffer 47 which can be referred to.

The layer 7 protocol control function unit 70 controls the entire data communication in cooperation with the communication control function unit 50.

When the layer 7 protocol control function unit 70 instructs the layer 6 protocol control function unit 68 to start data transmission, the layer 6 protocol control function unit 68
Document Application Profile (DAP)
Creates an abstract syntax based on and converts it into a transfer syntax. At this time, the transfer syntax is created on the shared memory 49 managed by the OS (operation system). The layer 6 protocol control function unit 68 creates reference information in the transmission order with respect to the created transfer syntax and contents (actual transmission data), transfers the information to the data reference information control function unit 56, and transmits the information to the layer 5 protocol control function unit 66. Make instructions.
Thereby, the reference information is stored in the memory area (not shown) of the management of the data reference information control function unit 56.

In the layer 5 protocol control function section 66,
A layer 5 protocol header is created on the shared memory 49 managed by the OS, and the reference information from the layer 6 is taken out via the data reference information control function unit 56, and based on this, the transmission data for the transmission unit of the layer 5 is transmitted. read out. After that, similarly, the reference information is created in the transmission order, transferred to the data reference information control function unit 56, and instructed to transmit to the layer 4 protocol control function unit 64.

The layer 4 protocol control function unit 64 and the layer 3 protocol control function unit 62 perform the same processing as the layer 5 protocol control function unit 66.

The layer 2 protocol control function unit 60 instructs the transmission BF control function unit 58 to acquire a transmission buffer,
The real data is read based on the reference information read via the data reference information control function unit 56, and an information field (I field) serving as an entity to be transmitted to the line is assembled. After that, the L2 protocol control function unit 60 instructs the device control function unit 52 to transmit to the line.

As a result, when the information field is transmitted and the transmission confirmation from the partner device is obtained, the layer 2 protocol control function unit 60 releases the transmission buffer in use.

FIG. 4 shows a configuration related to control at the time of data reception in the facsimile apparatus 10 as described above.
It is shown as a functional block diagram focusing on software.

Here, the operation when the transmission data is received from the line will be described with reference to FIG.

The line control function unit 72 that has detected an incoming call from the communication line notifies the system control function unit 48 of it.
The system control function unit 48 determines whether connection is possible based on resource management in the system, and notifies the line control function unit 72 of the result. At the same time, the communication control function unit 50 is activated to instruct the start of communication.

The communication control function unit 50 activates the protocol control function units 60 to 70 and instructs the start of communication. At the same time, it instructs the file control function unit 54 to secure a file for reception.

The layer 2 protocol control function unit 60 instructs the transmission BF control function unit 58 to secure a reception buffer whose number is equal to or more than the outstanding number (K), which is a layer 2 protocol parameter, and transfers the obtained transmission buffer to the device control function. Notify section 52.

The device control function unit 52 uses this as a reception buffer. Further, the device control function unit 52 stores each frame received from the line in the transmission buffer, and sends a data reception notification to the layer 2 protocol control function unit 60.

The layer 2 protocol control function unit 60 creates reference information of the information field, transfers it to the data reference information control function unit 56, and instructs the layer 3 protocol control function unit 62 to receive the information.

The layer 3 protocol control function section 62 reads the reference information of the received data via the data reference information control function section 56, analyzes the layer 3 protocol header, and creates reference information indicating the data of the upper layer. The data is transferred to the data reference information control function unit 56 and a reception instruction is issued to the layer 4 protocol control function unit 64.

The layer 4 protocol control function unit 64, the layer 5 protocol control function unit 66, and the layer 6 protocol control function unit 68 perform the same processing as that of the layer 3 protocol control function unit 62.

The layer 7 protocol control function unit 70 stores the received document data in the reception file 44 via the communication control function unit 50 and the file control function unit 54, and releases the reception buffer.

FIG. 5 shows the transmission buffer (BF) described above.
The configuration of the control function unit 58 is shown as a functional block diagram centering on software. In FIG. 5,
Also shown is a transmission buffer 46 consisting of a group of buffers and a user 74 consisting of the layer 2 protocol control function 60 and device control function 52 described above.

In FIG. 5, the transmission buffer control function unit 58 includes a user interface function unit 76, an initialization control function unit 78, and a buffer (BF) as a management unit, which are the core of the transmission buffer control function unit 58. Control block management function unit 80, buffer (BF) control block group 82, unused buffer management function units 84, 86, and 8 as unused memory queue management means for each frame size
8, 90, 92, and used buffer management function units 94, 9 as used memory queue management means for each frame size
6, 97, 98 and 99.

The user interface function unit 76 provides an interface from or to the user 74, and specifically provides services such as initialization, buffer acquisition, data writing, and buffer release.

Here, the initialization function of the user interface function unit 76 will be described with reference to FIG. 7 and along the flowchart of FIG.

In step 100, an unused BCB management queue (BCB unused management queue) is created. This creation
This is performed in the transmission data control area of the memory space via the BF control block management function unit 80 and the initialization control function unit 78 (see FIG. 7). Here, the BCB is a transmission BF control block, and its specific structure is shown in FIG.

The following data is stored or set in each section (each area) constituting the transmission BF control block shown in FIG. link for BCB: Pointer value for creating a BCB list structure name: Transmission data storage area (see FIG. 7)
Serial number sub when subdivided into basic name: Serial number when the basic divided transmission data storage area is further divided again link for master slave: When subdivision is performed, slave BCB if master, mas if slave
Pointer value to BCB of ter link for slave: Slave when subdivision is performed
Pointer value buffer to create list structure between pointer: Start address of the transmission buffer managed by this BCB date length: size of data to be transmitted when used for transmission, data size received from line when used for reception queue id: Queue where this BCB is managed release counter: Count value of data processed at the time of reception Buffer (B) designated by user 74 in step 102
F) Determine whether the size is 2K. Here, the user 74 may be the layer 2 protocol control function unit 60. Therefore, the instruction of the user 74 includes a case where the buffer size (corresponding to the frame size) is determined by the protocol.

If the determination in step 102 is affirmative, the process proceeds to step 104 to create a queue top of an unused 2K buffer, and then proceeds to step 106 to create a queue top of a used 2K buffer.

In the next step 108, it is determined whether or not there is a free space in the buffer space (memory space). If there is a free space in the memory space, the flow advances to step 110 to acquire the BCB.

In the next step 112, the memory space is set to 21
The start address of an area (block) divided in units of 92 octets is determined by the BFP (buffer) of the acquired BCB.
er pointer), the process proceeds to step 114 to connect the BCB to an unused 2K buffer queue, and then returns to step 108.

The above-mentioned 2192 octets are the length of one transmission buffer. The lengths are as follows: Layer 2 address = 1, Layer 2 control data = 2, Layer 3 header = 4, Layer 3 user data = 128, Layer 2 FCS
The sum of all (frame check sequence) = 2 is 137 octets, and 1 of this 137 octets
This is calculated as 2192 octets as 6 times.

Thereafter, steps 108 to 114
The BCB acquisition and B
The setting of the FP and the connection to the unused 2K buffer queue are sequentially performed (see FIG. 7).

If there is no free space in the memory space and the determination in step 108 is negative, step 1
After jumping to 16 to create a used / unused 1K buffer queue top, the process proceeds to step 132 to create a used / unused 512 buffer queue top. In the next step 134, a used / unused 256-buffer queue top is created, and in a step 136, a used / unused 128-buffer queue top is created, followed by terminating the initialization process (see FIG. 7).

On the other hand, if the determination in step 102 is negative, the process proceeds to step 118, and thereafter, in steps 118 to 130, step 10 is executed.
The same determination and processing as in steps 2 to 114 are performed for a buffer size of 1K (actual size is 1096 octets). If there is no free space in the buffer space (memory space) and the determination in step 124 is denied, step 13 is executed.
Proceed to 2.

Although illustration is omitted, the instruction from the user 74 indicates that the buffer size is 512 and the buffer size is 256.
In this case, the same processing as described above is performed. If there is no free space in the memory space, the process proceeds to steps 134 and 136, respectively. Instruction from user 74 is buffer size 1
In the case of 28, the same processing as described above is performed, but as soon as the memory space becomes full, the initialization processing ends.

That is, the user interface function unit 76
In this way, the buffer size (2K, 1K, 512, 256, 128) designated by the user 74 is used as a parameter to set the structure as the initial value of the buffer control block management function unit 80 smaller than the designated buffer size. Create it.

Next, the buffer acquisition function by the user interface function unit 76 will be described with reference to FIG.
This will be described with reference to the flowcharts of FIGS.

As shown in FIG. 9, steps 200 to
In step 206, it is determined whether the buffer size requested by the user 74 is 128, 256, 512, or 1K.

For example, if the requested size of the user 74 is 512
If the answer is yes, the determination in step 204 is affirmed,
Proceeding to step 218, it is determined whether there are 512 unused buffers. If the determination in step 218 is affirmative, the process proceeds to a subroutine of a 512 buffer acquisition process in step 222. Step 2
If the determination at 18 is negative, step 22
The process proceeds to a subroutine of a new 512 buffer acquisition process of 0.

In the subroutine of the 512 buffer acquisition process, as shown in FIG.
Take out 512 BCBs from buffer unused queue 5
Link to 12 buffer usage queue. Next step 3
In 02, a pointer to a buffer corresponding to the BCB is returned to the user 74 as a return value, and the process returns to the main routine to immediately end a series of processes.

In the subroutine of the new 512 buffer acquisition process, as shown in FIG.
The 2K BCB () is extracted from the K buffer unused queue and linked to the 2K buffer used queue (see FIG. 12).

In the next step 402, four BCBs (,,,) are taken out from the BCB unused queue, and 5
Link to the 12 buffer unused queue (see FIG. 12).

In the next step 404, BCB (,,
,) Sub name 、 queue id, link for slav
e, BFP, and then in step 406, the BCB
(,,,,) link for master slave
Set.

In the next step 408, after extracting 512 BCBs from the 512 buffer unused queue and linking them to the 512 buffer used queue (see FIG. 12), in step 410 the user returns the pointer value to the buffer corresponding to the BCB as the return value. Returning to step 74, the process returns to the main routine and immediately ends a series of processing.

Similarly, for example, if the requested size of the user 74 is 1K, the determination in step 206 is affirmative, and the flow advances to step 212 to determine whether there is a 1K unused buffer. If the determination in step 212 is affirmative, the process proceeds to a subroutine of 1K buffer acquisition processing in step 216. Step 2
If the determination in step 12 is negative, step 21
Then, the process proceeds to a subroutine for new 1K buffer acquisition processing of No. 4. Further, for example, when the requested size of the user 74 is 2K, the processing shifts to a subroutine of 2K buffer acquisition processing in step 210.

In these subroutines, the aforementioned 51
The same processing as in the case of two buffers is performed. For example, although not shown, for example, in a subroutine of a new 1K buffer acquisition process, two BCBs (this number is determined according to the buffer size) are extracted from the BCB unused queue, and linked to the 1K buffer unused queue. Then, 1K BCB is taken out from the 1K buffer unused queue and linked to the 1K buffer used queue. Similar processing is performed when the requested size of the user 74 is 256, 128.

The user interface function unit 76 operates a transmission buffer having a large size as a transmission buffer having a smaller size, using the buffer length to be acquired as a parameter.

Next, the buffer releasing function by the user interface function unit 76 will be described with reference to the flowchart of FIG. In the case of FIG. 13, a flowchart of releasing the buffer when initialized at 2K is shown.

First, in step 500, the corresponding 2K BCB is obtained from the pointer value to the released data, and
Go to 02 and link of the BCB for master Check slave.

In the next step 504, link for mast
er Based on the result of examining the slave, it is determined whether or not subdivision has been performed. If not, step 5
06 and release of the BCB Add counter for the open data length.

In the next step 508, the release of the BCB is performed.
e counter and date Compare length and step 510
Then, it is determined whether or not all can be opened based on the comparison result. If all of them can be released, the process proceeds to step 512, where the BCB is taken out from the 2K buffer use queue, returned to the 2K buffer unused queue, and
After releasing the buffer area managed by B, a series of processing ends. On the other hand, if it is determined in step 510 that all data cannot be released (there is unprocessed data),
The process ends immediately.

On the other hand, in step 504,
If it is determined that the image is divided, the process proceeds to step 514.
Go ahead and link of the BCB for master Split from slave
To obtain the BCB of the buffer,
The BCB queue that I found Find the number of divisions from id.

In the next step 518, the corresponding BCB is obtained from the pointer value to the release data. In step 520, the release of the BCB is performed. Add counter for the open data length.

In the next step 522, the release of the BCB is performed.
e counter and date After comparing the length, step 5
The process proceeds to 24, and it is determined whether or not all can be opened based on the comparison result. If all of them can be released, the process proceeds to step 526 to take out the BCB from the corresponding use queue, return it to the corresponding unused queue, release the buffer area managed by the BCB, and end a series of processing. . On the other hand, if it is determined in step 524 that all of them cannot be released, the process is immediately terminated.

That is, the user interface function unit 76 releases the buffer initialized by 2K using the pointer value to the data to be released and the length to be released as parameters.

The data writing function is performed using the pointer value to the data to be written and the length of writing as parameters.
Except for setting the length, the process is the same as the normal transfer process, and a detailed description is omitted.

As described above, according to the first embodiment, the memory area is subdivided in accordance with the buffer size requested by the user at the time of transmission, so that memory management suitable for the frame size can be performed, and Use efficiency can be improved.

Further, when a block (memory area) that is being used after being subdivided is released, the block is returned to the initial state, so that the unused memory can be used effectively after release.

In particular, when the user 74 is the layer 2 protocol control function unit 60, when the frame size is determined by the protocol negotiation, the memory is divided into blocks suitable for the frame size as an initial state. Can be reconstructed, and in such a case, the overhead part for optimizing the block to the frame size during transmission can be reduced.

<< Second Embodiment >> Next, a second embodiment of the present invention will be described with reference to FIG. 9 and FIGS.

In the second embodiment, the link for whether all buffers linked by slave have been freed
Release of master It is characterized in that it is controlled by the counter, and the configuration of the other parts is the same as that of the first embodiment.

Here, the function of the user interface function unit 76 in the second embodiment when acquiring a buffer is shown in FIG.
14 and FIG. 15 will be described.

The main routine in this case is as shown in FIG.
The main routine at the time of buffer acquisition of the first embodiment is used as it is, and the subroutine of 2K buffer acquisition processing in step 210 of this main routine is the same as that of the first embodiment. However, the subroutine of the buffer acquisition process with a buffer size of 1K or less and the subroutine of the new buffer acquisition process are different.

Therefore, here, a subroutine of 1K buffer acquisition processing and a subroutine of new 512 buffer acquisition processing will be described.

In the 1K buffer acquisition subroutine, as shown in FIG. 14, in step 600, 1K BCB is taken out of the 1K buffer unused queue and linked to the 1K buffer used queue. In the next step 602, link for master rel of master BCB than slave
ease After the counter is decremented (decremented by 1), the process proceeds to step 604 to return a pointer to a buffer corresponding to the BCB to the user 74 as a return value, and then returns to the main routine to immediately end a series of processes.

In the subroutine of the new 512 buffer acquisition process, as shown in FIG.
The 2K BCB () is extracted from the K buffer unused queue and linked to the 2K buffer used queue (see FIG. 12).

In the next step 702, the release of the BCB is performed.
e After setting -1 to counter, the process proceeds to step 704, where four BCBs (,,
,) Is taken out and linked to a 512-buffer unused queue (see FIG. 12).

In the next step 706, BCB (,,
,) Sub name 、 queue id, link for slav
e, BFP, and then in step 708, the BCB
(,,,,) link for master slave
Set.

In the next step 710, 512 BCBs are taken out from the 512-buffer unused queue and linked to the 512-buffer use queue (see FIG. 12). Returning to step 74, the process returns to the main routine and immediately ends a series of processing.

In the subroutine for obtaining a new 1K buffer,
Two BCBs are taken out from the BCB unused queue, and 1
Linked to K buffer unused queue, then 1K BCB is taken out from 1K buffer unused queue and 1
Except for the fact that the subroutine is linked to the K buffer use queue, the same processing as that of the above-described subroutine for acquiring a new 512 buffer is performed, and therefore detailed description is omitted. Further, when the requested size of the user 74 is 256, 128, the same processing is performed.

Next, the buffer release function by the user interface function unit 76 in the second embodiment will be described.
This will be described with reference to the flowchart of FIG. This FIG.
In the case of, the flow of releasing the buffer when the initialization is performed at 2K is shown.

In steps 800 to 824, the same processing and judgment as those in steps 500 to 824 in the first embodiment are performed, and when the judgment in step 824 is affirmed, step 826 is executed.
Proceed to.

In step 826, the master of the BCB re
lease The counter is incremented (incremented by 1), and the master is released in the next step 828. It is determined whether or not the count value of the counter is 0. This step 828
If the determination in step (1) is negative, the process proceeds to step 830, where the BCB is taken out from the corresponding use queue and returned to the corresponding unused queue, and then a series of processing ends. on the other hand,
If the determination in step 828 is affirmative, the flow advances to step 832 to take out the divided BCB from the 2K buffer use queue to release all the divided BCBs.
After returning to the K buffer unused queue, a series of processing ends.

As described above, the link for release of master if all buffers linked by slave have been released It is controlled by the counter.

Therefore, in the case of the second embodiment,
The unused memory can be effectively used.

<< Third Embodiment >> Next, a third embodiment of the present invention will be described with reference to FIG.

In this embodiment, the link for release of master if all buffers linked by slave have been released It is characterized in that it is controlled by the counter and that the actual release processing is executed by the timer processing of the OS (operation system), and the configuration of the other parts is the same as in the first embodiment. .

Here, the buffer release function by the user interface function unit 76 in the third embodiment will be described with reference to the flowchart of FIG. FIG. 17 shows a flow of releasing a buffer when the buffer is initialized at 2K.

In steps 900 to 928, the same processing and judgment as those in steps 800 to 828 in the second embodiment are performed.
If the determination in step 8 is negative, the process proceeds to step 930, where the BCB is taken out from the corresponding use queue and returned to the corresponding unused queue, and then a series of processing ends. On the other hand, if the determination in step 928 is affirmative, the process advances to step 932 to request the OS to release all the buffer units after a specified time, and thereafter, a series of processing ends.

As a result, after the designated time, the OS releases all the buffers. Therefore, the overhead of the buffer management process can be reduced.

<< Fourth Embodiment >> Next, a fourth embodiment of the present invention will be described.

In the fourth embodiment, a buffer having a maximum size is prepared in advance when data is received, and when the size of the actually received data is smaller than a specified value, a table for managing the remaining area is activated, Can be used for other transmission and reception.

Here, the function at the time of data reception by the user interface function unit 76 in the fourth embodiment will be described with reference to the flowchart of FIG. It is assumed that initialization is performed at 2K in the same manner as in the first embodiment.

In step 1000, the received data size is set to the data of the BCB. After setting to length, step 1002
In step 1008, the received data size is determined.

For example, if the received data size is greater than 256 octets and less than or equal to 512 octets, the determination at step 1006 is affirmed, and step 1018 is performed.
To obtain three new BCBs. Next Step 1
In step 020, after setting the data in the free area in the BCB, the process proceeds to step 1022, where the reception notification processing to the layer 2 protocol control function unit 60 is performed, and the series of processing ends.

If the received data size is larger than 512 octets and equal to or smaller than 1K octets, for example, the determination in step 1008 is affirmed, and step 101 is performed.
Proceed to 2 to obtain a new BCB. Next Step 10
In step 14, the data in the free area is set in the BCB, and the process proceeds to step 1016, where the layer 2 protocol control function unit 6
After performing the reception notification processing for 0, a series of processing ends.

As described above, in the fourth embodiment, when the data size actually received is smaller than the size of the transmission buffer prepared in advance, the BCB for managing the free area is newly acquired. The transmission buffer can be used effectively.

<< Fifth Embodiment >> Next, a fifth embodiment of the present invention will be described.

In the fifth embodiment, a counter (counter) for controlling reception buffer not ready is used. RNR
) Is held in the 2K buffer unused queue, and is subtracted (decremented by 1) each time the BCB is removed from the queue, and added (increased by 1) when linked. The state of the 2K buffer unused queue in the fifth embodiment is shown in FIG.

In the user interface function unit 76, coun
ter When the count value of the RNR becomes equal to or smaller than a first predetermined value, the reception failure state is notified to the layer 2 protocol control function unit 60.

On the other hand, the release of the buffer progresses,
r When the count value of the RNR becomes equal to or larger than a second predetermined value set in advance, the reception enable state is notified to the layer 2 protocol control function unit 60.

When the layer 2 protocol control function unit 60 receives the notification of the reception disabled state, it stops the data flow described above, and conversely, upon receiving the notification of the reception enabled state, restarts the data flow.

Therefore, there is an effect that the management of the transmission buffer / reception buffer can be performed in an integrated manner.

As apparent from the above description, in the first to fifth embodiments, the transmission buffer (BF) control function unit 58, more specifically, the user interface function unit 76
The first means, the second means, the third means, the fourth means, the fifth means
It can be seen that the means, the sixth means, the seventh means, the eighth means, and the ninth means are realized.

[0169]

As described above, according to the data transmission apparatus of the first aspect, memory management suitable for the frame size of the transmission data can be performed. Even with this, it is possible to improve the use efficiency of the memory and reduce the memory area used for data transmission, so that it is possible to reduce the cost by reducing the size of the memory. effective.

According to the data transmission device of the second aspect,
In addition to the effect of claim 1, when the frame size is determined by the protocol at the time of transmission, the block is subdivided into a size suitable for the frame size as an initial state by the third means, and the memory is reconfigured. In addition, the overhead for optimizing the frame size can be reduced.

According to the data transmission device of the third aspect,
In addition to the effect of claim 1, when all the blocks in use that are subdivided by subdivision are released, the blocks are returned to the initial state by the seventh means, so that the unused memory after opening is valid. It can also be used for

According to the data transmission device of the fourth aspect,
In addition to the effect according to claim 1, in a case where all the used blocks have been released by being subdivided by subdivision, the waiting state is maintained for a preset time by the eighth means, and then the block is initialized. , The overhead of the memory management process can be reduced.

According to the data transmission device of the fifth aspect,
When the count value of the counter that counts the number of usable or unusable memories for each frame size reaches a first specified value, the protocol control function unit stops the data flow, releases the memory, and releases the count value of the counter. When the data reaches the second specified value, the data flow is resumed by the protocol control function unit.
There is an effect that the management of the reception buffer can be performed in an integrated manner.

According to the data transmission apparatus of claim 6,
At the time of reception, if the actually received frame size is smaller than the specified value, the ninth means newly secures a table for managing the remaining area using the management means, the used memory queue management means and the unused memory queue management means. Therefore, the transmission buffer can be effectively used even at the time of reception.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a facsimile apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram for describing a protocol when the facsimile apparatus and the like in FIG. 1 communicate with each other via an ISDN network.

FIG. 3 is a functional block diagram showing a configuration related to data transmission of the facsimile apparatus of FIG. 1 with a focus on software.

FIG. 4 is a functional block diagram showing a configuration related to data reception of the facsimile apparatus of FIG. 1 with a focus on software.

FIG. 5 is a functional block diagram showing a specific configuration of a transmission buffer control function unit of FIG. 2;

FIG. 6 is a flowchart showing an initialization routine of a user interface function unit shown in FIG. 5;

FIG. 7 is a diagram showing a logical structure when initialization is performed at 2K according to the flowchart of FIG. 6;

FIG. 8 is a diagram showing a structure of a transmission buffer control block.

FIG. 9 is a flowchart showing a buffer acquisition routine of the user interface function unit of FIG. 5;

FIG. 10 is a flowchart showing a subroutine of a 512 buffer acquisition process of FIG. 9;

FIG. 11 is a flowchart showing a subroutine of a new 512 buffer acquisition process of FIG. 9;

FIG. 12 is a diagram showing a logical structure when a 512 buffer acquisition process is performed according to the flowcharts of FIGS. 9 to 11;

FIG. 13 is a flowchart showing a buffer release routine of the user interface function unit of FIG. 5;

FIG. 14 is a flowchart illustrating a subroutine of 1K buffer acquisition processing in a buffer acquisition routine of a user interface function unit according to the second embodiment.

FIG. 15 is a flowchart illustrating a subroutine of a new 512 buffer acquisition process in a buffer acquisition routine of the user interface function unit according to the second embodiment.

FIG. 16 is a flowchart illustrating a buffer release routine of a user interface function unit according to the second embodiment.

FIG. 17 is a flowchart illustrating a buffer release routine of a user interface function unit according to the third embodiment.

FIG. 18 is a flowchart illustrating a processing routine when data is received by the user interface function unit according to the fourth embodiment.

FIG. 19 is a diagram illustrating a state of a 2K buffer unused queue according to the fifth embodiment.

[Explanation of symbols]

Reference Signs List 10 facsimile device (data transmission device) 46 transmission buffer (storage unit) 76 user interface function unit (first unit, second unit, third unit, fourth unit, fifth unit, sixth unit, seventh unit, seventh unit Eighth means, ninth means,) 80 Buffer control block management function section (management means) 84, 86, 88, 90, 92 Unused buffer management function section (unused memory queue management means) 94, 96, 97, 98, 99 Used buffer management function unit (used memory queue management means)

Continuation of the front page (56) References JP-A-6-54026 (JP, A) JP-A-2-271755 (JP, A) JP-A-3-145242 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H04L 29/06 H04L 13/08 H04N 1/32

Claims (6)

(57) [Claims] 1. A data transmission device implementing a protocol defined to use a plurality of sizes of frame lengths (L) and a plurality of outstanding numbers (K) in a data link layer of an OSI reference model, comprising: A first means for blocking the data storage area corresponding to a maximum frame length (L _MAX ) as an initial state and associating the data storage area with a management table on a one-to-one basis; Management means for managing the blocked data storage area; used memory queue management means and unused memory queue management means for each frame size; and, during transmission, the management means, used memory queue management means and unused memory. A block of a size suitable for the required memory size of one block using the queue management means Second means for subdividing the data transmission apparatus having a. 2. When a frame size is determined by a protocol, one block is divided into blocks of a size suitable for the frame size using the management means, the used memory queue management means and the unused memory queue management means. 2. The data transmission apparatus according to claim 1, further comprising third means for reconfiguring the memory as an initial state. 3. The data transmission apparatus according to claim 1, further comprising fourth means for returning the block to an initial state when all the blocks in use by being subdivided by subdivision are released. 4. When a block that has been subdivided by subdivision and all in-use blocks have been released is maintained in a waiting state for a preset time, the block is returned to an initial state.
2. The data transmission device according to claim 1, further comprising means. 5. A counter for counting the number of usable or unusable memories for each frame size, sixth means for increasing / decreasing the count value of the counter when the memory is used and when the memory is released, and wherein the count value of the counter is A seventh means for notifying the protocol control function unit of the reception disabled state when the first specified value is reached, and a reception enabled state for the protocol control function unit when the memory is released and the count value of the counter reaches the second specified value 8. The data transmission device according to claim 1, further comprising: an eighth unit for notifying the following. 6. A data transmission device implementing a protocol defined to use a plurality of frame lengths (L) and a plurality of outstanding numbers (K) in a data link layer of an OSI reference model, comprising: A first means for blocking the data storage area corresponding to a maximum frame length (L _MAX ) as an initial state and associating the data storage area with a management table on a one-to-one basis; Management means for managing the blocked data storage area; used memory queue management means and unused memory queue management means for each frame size; and when the actually received frame size is smaller than a prescribed value, the management means; The remaining area is managed using the used memory queue management means and the unused memory queue management means. Data transmission device comprising a ninth means for newly secure a table, a.