JP3343460B2 - HDLC frame processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an HDLC (high-
HDLC for storing and reading frame data in level data link control
The present invention relates to a frame processing device.

[0002]

2. Description of the Related Art HDLC frames (LAPB frames,
A conventional configuration of a memory (frame buffer) for storing frame data in an apparatus for processing an LAPD frame or the like will be described below. FIG. 3 is a block diagram showing a buffer configuration of a conventional frame processing device.

[0003] In order to store one frame of frame data 201, a plurality of large-size buffers 203 having a size larger than the maximum frame length are provided as frame buffers 202 for frame data 201 having a certain size. It is assumed that one buffer 203 is used. At the start of writing frame data to the frame buffer 202, a write processing unit (not shown) hunts one empty large-size buffer 203 from the empty buffer pool and writes frame data from the head position of the buffer.

[0004] After the frame data write is completed, a buffer number and an offset from the head of the page (hereinafter, a final pointer) are notified to a read processing unit (not shown) as frame management information. When reading frame data from the frame buffer 202, the above-described read processing unit reads from the head of the buffer notified by the write processing unit to the last pointer, and releases the buffer to an empty buffer pool.

FIG. 4 is a block diagram showing another buffer configuration of the conventional frame processing device. This is because, for frame data 301 having a certain size, a large number of memory blocks (hereinafter, referred to as pages 303) of the same size are provided as a frame buffer 302, and the number of pages 303 corresponding to the frame length is chained. , Frame data 3
01, and each page 303 of the frame buffer 302 has, as management information, a chain presence / absence flag, a next page number, and a last pointer (only in the case of the last page).

At the start of frame data writing, a write processing unit (not shown) hunts free pages from the free page pool, stores the page number as the first page number of the frame management information, and stores the frame data from the top of the page. To write. Write to the end of the page, and if the frame data still continues, hunt a new page from the free page pool again. Then, the chain presence / absence flag of the management information of the written page is set to “chain present”, and the new page number hunted immediately is written to the next page number of the management information of the written page. This chain processing is repeated as long as the frame data continues.

When the writing of the last data of the frame is completed, the chain presence / absence flag of the management information of the page being written is set to “no chain”, and the last write pointer is written to the last pointer of the management information of the page being written. Then, it notifies the read processing unit (not shown) of the first page number of the frame management information stored in advance.

[0008] In the reading of the frame data from the frame buffer 302, the read processing unit first sets the first page number of the frame management information received from the write processing unit as the read page. Then, the chain presence / absence flag of the management information of the page is “no chain”
In the case of, the last pointer of the management information is read, and the frame data is read up to the last pointer, and the data read process is completed. Then, the page is released to the free page pool.

When the chain presence / absence flag of the management information of the page is "chain present", the next page number of the management information is read, and the frame data is read until the end of the page. Then, the page is released to the free page pool. Subsequently, the next page is set as the lead page, and the same processing is repeated until the chain presence / absence flag of the management information of the page becomes “no chain”.

[0010]

However, in the conventional first buffer configuration, even when storing frame data of any size, one frame buffer larger than the maximum frame length is used. When short frame data is stored in a frame buffer having a large length, the use efficiency of the frame buffer is low.

Further, since a large number of buffers must be provided in order to realize a sufficient throughput, a large-capacity frame buffer memory is required, resulting in high cost. With the conventional second buffer configuration, a high-speed (short access time) memory is required because the chain processing of the frame buffer is complicated and the memory for storing the management information is accessed many times. Therefore, it is difficult to apply the system to a system that processes frame data at high speed.

[0012]

To solve the problems described above SUMMARY OF THE INVENTION The present invention provides a HDLC frame processing apparatus having a buffer for processing frames de <br/> over data transmitted in frame units, each of the plurality When there are two or more groups of buffers with the number of planes, and the buffers of each group are combined one by one
Frame the total size of sets the face size of the buffer in the same size for each of the groups to be greater than the maximum length of one frame data, defining the order of the group to be used
A buffer, said for one frame data, and a processing unit that uses the buffer of each group <br/> one by one face
It is characterized by the following .

[0013]

SUMMARY OF] The present invention having the structure described above, when receiving the frame data, first, store the data in the buffer of the first one side of the group that is determined so as to house the data, it can not be stored in this buffer For frame data of length,
By the procedure of storing in the buffer of one side of the next group ,
One frame data can be used up to one buffer per group.
To store .

[0014]

FIG. 1 is a block diagram of a frame processing apparatus according to a first embodiment of the present invention, which is applied to an apparatus for processing a LAPB frame. Where L
The maximum I (information) field length of the APB frame is 409
Since it is 9 bytes, when the AC (address, control) field is 3 bytes, a maximum of 4102 bytes is required to store one frame as a frame buffer.

Reference numeral 1 denotes a frame buffer. The frame buffer 1 includes a primary buffer 2 having a size of several tens to several hundreds of bytes and a secondary buffer 3 having a size of several kbytes. The primary buffer 2 is composed of a plurality of buffers of the same size, and the secondary buffer 3 is composed of a buffer of a plurality of surfaces of the same size.
Is relatively infrequently used, and thus has a smaller number of planes than the primary buffer 2. Then, both the primary buffer 2 and the secondary buffer 3 are set so that the sum of the size of one surface of the primary buffer 2 and the size of one surface of the secondary buffer 3 is larger than the maximum frame length (4102 bytes). If used, one frame data can be stored. Note that the sizes and the number of planes of the primary buffer 2 and the secondary buffer 3 are determined according to the traffic conditions of the applicable system.

Reference numeral 4 denotes a frame buffer management unit which manages an empty primary buffer and an empty secondary buffer in the primary buffer 2 and the secondary buffer 3. The frame buffer management unit 4 is connected to the write processing unit 6 by a transmission line 5, connected to the read processing unit 8 by a transmission line 7, connected to the primary buffer 2 by a transmission line 9,
Is connected to the secondary buffer 3.

The write processing unit 6 receives the frame data of the LAPB frame via the transmission line 11. The read processing unit 8 transmits the frame data of the LAPB frame via the transmission path 12. When storing one frame data, the write processing unit 6 first stores the data in the primary buffer 2 and then stores the data in the secondary buffer 3. And the secondary buffer 3 are used in order. As a result, if the data length of one frame does not exceed the size of the primary buffer 2, only the primary buffer 2 is used, and
If the frame data length exceeds the size of the primary buffer 2, the secondary buffer 3 is also used. When reading out one frame data, the read processing unit 8 reads out one frame data from the primary buffer 2 and then reads out the data from the secondary buffer 3. The secondary buffer 3 is used in order.

At this time, the read processing unit 8 reads frame data based on the management information notified from the write processing unit 6, but determines the number of buffers required for one frame data in advance. , And the order in which the primary and secondary buffers are used,
Since information required as management information can be reduced, access to the management information by the read processing unit 8 can be reduced.

According to the above configuration, L
When you start receiving the frame data of the APB frame,
The write processing unit 6 writes frame data to the empty primary buffer 2 via the frame buffer management unit 4 first. When the frame data continues beyond the size of one surface of the primary buffer 2, the write processing unit 6 writes the rest of the frame data to the empty secondary buffer 3 via the frame buffer management unit 4. Here, as described above,
Since the sum of the size of one surface of the primary buffer 2 and the size of one surface of the secondary buffer 3 is set to be larger than the maximum frame length, one frame data is transmitted to both the primary buffer 2 and the secondary buffer 3. If they are used, they can always be stored, and the storage order is the primary buffer 2 first.

When the reception of the frame data of the LAPB frame is completed, the write processing unit 6 uses the number of the used primary buffer 2 and the secondary buffer use flag (indicating whether the secondary buffer is used or not) as management information. ), The information of the used secondary buffer 3 and the last pointer is sent to the read processing unit 8, and the writing of the frame data to the frame buffer 1 is notified.

Here, the management information memory for storing the management information described above is provided in the read processing unit 8. Note that the frame buffer management unit 4 may have it. When the read processing unit 8 reads the frame data from the frame buffer 1, it accesses the management information received from the write processing unit 6 and stored in the management information memory,
The corresponding primary buffer 2 is read from the primary buffer number, and if the secondary buffer is not used by referring to the secondary buffer use flag, the final pointer is read and the frame data is read up to the final pointer. Then, the data read processing is completed. When the secondary buffer is used, the corresponding secondary buffer 3 is read from the secondary buffer number, the final pointer is read, and the frame data is read up to the final pointer, thereby completing the data read processing.

As described above, in this embodiment, two types of buffers are used for one frame according to the frame length, and these buffers are used as a primary buffer and a secondary buffer. If the primary buffer is used first and frame data of a length that cannot be stored in the primary buffer is used, a secondary buffer is used. If these frames are used in this order one by one, complicated chain processing is required. However, since the number of accesses to the management information memory is reduced, it is possible to use a relatively low-speed (long access time) memory as the management information memory and apply it to a high-speed frame processing system. In particular, when the present invention is applied to a system in which frames of a plurality of channels are transmitted and received in a time-division multiplex manner, access to management information necessary for channel switching of frame buffer access and buffer management information necessary for hunting a new buffer are performed. However, in this embodiment, there is no chain processing associated with the new buffer hunt, so that the processing is not complicated and is very effective.

The primary buffer 2 is a small buffer, the secondary buffer 3 is a large buffer, and only the primary buffer 2 is used for short frames. If the secondary buffer 3 is also used only when the secondary buffer 3 is used, a large number of small-sized primary buffers 2 are needed, but a small number of large-sized secondary buffers 3 are sufficient, and the buffer memory usage efficiency is high. Can be expected to improve.

In the above-described embodiment, the case where the present invention is applied to an apparatus for processing a LAPB frame has been described. However, if the buffer size is changed, the present invention can be applied to an apparatus for processing an LAPD frame. FIG. 2 is a block diagram of a frame processing apparatus according to a second embodiment of the present invention.
This is a case where the present invention is applied to a device that processes a PD frame.

Here, CCITT Recommendation Q. According to 921, since the maximum I-field length of the LAPD frame is 260 bytes (default), when the AC field is 4 bytes, a maximum of 264 bytes is required to store one frame as a frame buffer. Therefore, 1
The primary buffer has the same size (Equation 10) so that the sum of the size of one surface of the secondary buffer and the size of one surface of the secondary buffer is larger than the maximum frame length (264 bytes).
By configuring the secondary buffer with a plurality of buffers of the same size (several tens to several hundreds of bytes) and a plurality of buffers of the same size (several tens to several hundreds of bytes), it is also applicable to the LAPD frame processing device.

That is, reference numeral 21 denotes a frame buffer. The frame buffer 21 includes a primary buffer 22 having a size of several tens to several hundreds of bytes and a secondary buffer 23 having a size of several tens to several hundreds of bytes. The primary buffer 22 is composed of a plurality of buffers of the same size,
The next buffer 23 is composed of a plurality of buffers of the same size.

The sum of the size of one surface of the primary buffer 22 and the size of one surface of the secondary buffer 23 is set to be larger than the maximum frame length (264 bytes).
If both the secondary buffer 22 and the secondary buffer 23 are used,
One frame data can be stored. Note that the sizes and the number of planes of the primary buffer 22 and the secondary buffer 23 are determined by the traffic conditions of the applicable system.

Reference numeral 24 denotes a frame buffer management unit.
The empty primary buffer and the empty secondary buffer in the next buffer 22 and the secondary buffer 23 are managed. The frame buffer management unit 24 is connected to a write processing unit 26 by a transmission line 25, and is read by a read processing unit 28 by a transmission line 27.
, And connected to the primary buffer 22 via a transmission line 29, and connected to the secondary buffer 23 via a transmission line 30.

The write processing unit 26 receives the frame data of the LAPD frame via the transmission line 31.
In addition, the read processing unit 28 transmits the LAP
The frame data of the D frame is transmitted. According to the above configuration, when the frame data of the LAPD frame starts to be received via the transmission line 31, the write processing unit 26 transmits the empty primary buffer 2 via the frame buffer management unit 24.
2 is written with frame data. Frame data is 1
When continuing beyond the size of one surface of the next buffer 22,
The write processing unit 26 writes the rest of the frame data to the empty secondary buffer 23 via the frame buffer management unit 24.

When the reception of the frame data of the LAPD frame is completed, the write processing unit 26
The number of the primary buffer 22 used, the secondary buffer use flag (indicating whether or not the secondary buffer is used), the number of the secondary buffer 23 used, and the information of the last pointer are sent to the read processing unit 28, and the The frame data writing to the buffer 21 is notified.

Here, it is assumed that the read processing unit 28 has a management information memory for storing the above-mentioned management information.
It should be noted that the frame buffer management unit 24 may have it. When the read processing unit 28 reads frame data from the frame buffer 21, the write processing unit 26
When the secondary buffer 23 is not used, the corresponding primary buffer 22 is read from the primary buffer number, and the secondary buffer 23 is referred to by referring to the secondary buffer use flag, by accessing the management information received from the management information stored in the management information memory. Reads the last pointer, reads the frame data up to the last pointer, and completes the data read processing. When the secondary buffer 23 is used, the corresponding secondary buffer 23 is read from the secondary buffer number, the final pointer is read, and the frame data is read up to the final pointer, thereby completing the data read processing. .

As described above, even an apparatus for processing an LAPD frame uses two types of buffers for one frame data, and uses these buffers as a primary buffer and a secondary buffer, one by one. When used in this order, complicated chain processing is not required, and the number of accesses to the management information memory is reduced. Therefore, a relatively low-speed (long access time) memory is used as the management information memory, and a high-speed frame processing system is used. It is possible to apply to

In each of the above embodiments, two types of buffers are used one by one, and a maximum of two buffers are used in accordance with the length of the frame data. Up to 3 for the data
If it is determined in advance how many buffers are to be allocated to one frame data, such as one plane or four planes, two or more types of buffers may be used one by one.

That is, in the case of the conventional page method, it is necessary to provide management information corresponding to each buffer to check whether or not another buffer is used and which buffer is used. Will increase,
If the number of buffers to be used for one frame data is determined and the order of access is determined, one frame data can be stored in a plurality of buffers, and can be made to correspond to each buffer. You don't need to have any management information,
Processing of frame data can be performed at high speed.

[0035]

As described above, the present invention provides a frame
Buffer that processes frame data transmitted in units of programs
In the HDLC frame processing device provided with
It has two or more groups of buffers with multiple faces,
The total size of one frame at a time is one frame
Back up each group so that it is longer than the maximum data length.
Set the face size to the same size and use
A frame buffer in which the order of groups
For each frame data, the buffer of each group is
And a processing unit to be used for
When storing one frame data in multiple buffers
Also eliminates the need for complicated chain processing,
Can be applied to systems that process
is there.

Further, since there is no need to use a large-capacity frame buffer, the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a frame processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a frame processing device according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a buffer configuration of a conventional frame processing device.

FIG. 4 is a block diagram illustrating another buffer configuration of a conventional frame processing device.

[Explanation of symbols]

 Reference Signs List 1 frame buffer 2 primary buffer 3 secondary buffer 4 frame buffer management unit 6 write processing unit 8 read processing unit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-64-93235 (JP, A) JP-A-5-160860 (JP, A) JP-A-4-237238 (JP, A) JP-A 62-93238 40559 (JP, A) JP-A-62-100049 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 29/08 H04L 13/08

Claims (3)

(57) [Claims] An HDLC frame processing apparatus including a buffer for processing frame data transmitted in frame units, comprising: two or more groups of buffers each having a plurality of planes ;
The total size of the group to be greater than the maximum length of a frame data when the combined buffer in each group, one surface
Turn <br/> surface size of the buffer with the set to the same size for each, and a frame buffer which defines the order of the group to be used, said for one frame data, a buffer of the respective groups one by one face HDLC frame processing unit, characterized in that it and a processing unit to be used for. 2. A HDLC frame processing apparatus according to claim 1, made different for each group of surface size of the buffer, the buffer surface number of the group, with a buffer of large surface Sa <br/> size, small surface HDLC frame processing apparatus is characterized in that less than buffer surface number of the group, with a buffer of Sa <br/> size. 3. The HDLC frame processing device according to claim 1, wherein the processing unit uses a write processing unit that writes frame data to the buffer, and a read processing unit that reads frame data from the buffer, and A storage unit for storing the information indicating the buffer used by the write processing unit,
The storage unit notifies the storage unit of information indicating whether a buffer next to the buffer used by the write processing unit has been used as the management information, and the read processing unit sequentially executes the buffer from the buffer based on the management information. An HDLC frame processing device for reading frame data.