JPH0732403B2 - Buffer management method - Google Patents

Description

The present invention relates to a buffer management system in an exchange.

(Prior Art) DDX for buffer management method in packet switching
-2 Primary study of packet switching method (Research Practical Report 26
Volume 8 (1977) pp. 2383-2397). The structure is shown in FIG. The figure shows an example of the configuration of a buffer management system for storing transmission / reception information in packet switching. First, the HDLC (High Level D
Information using the ata Link Control procedure is sent to the exchange 1. When the receiving unit 2 of the exchange 1 receives the information from the host A or the other station C, it requests the receiving buffer allocating unit 6 for a buffer for accumulating the information. The receiving buffer allocating unit 6 notifies the receiving unit 2 of an empty buffer which is allocated in advance for each device in accordance with the request of the receiving unit 2 and issues an empty buffer request to the common buffer pool 5 to acquire an empty buffer. The number of buffers allocated to each device such as the host A and the other station C is fixedly determined for each device at the time of contract.

Upon reception of an empty buffer from the reception buffer allocation unit 6, the reception unit 2 Host A or In order to accumulate the information received from other station C, and to send the information to the transmitter 4 after the reception is completed. As a sequence, put them in queue 2 _-1 , 2 _-2 . The processing device 3 is the same as the processing device 3 in the holding state of the receiving unit 2. From the queues 2 _-1 , 2 _-2 , analyzes the destination device, etc., and sends it to the destination transmission unit 4 And put them in the transmission queue 4 _-1 , 4 _-2 in sequence. Here, when the number of waiting buffers is larger than a predetermined number, Will be discarded as. The discarded buffer area is notified to the common buffer pool 5. The transmission unit 4 has transmission queues 4 _-1 , 4
_-2 Are sequentially taken out, and the information accumulated in the buffer area is transmitted to the host B or other station D, respectively. When the contents stored in the buffer are transmitted, the buffer waits for confirmation of the response, and only after the confirmation response is received from the transmitting host B and other station D. Is notified to the common buffer pool 5.

(Problems to be Solved by the Invention) However, in the above-described exchange, a device having a strict delay time condition from reception to transmission of information, for example, a line device and a device having a strict delay time condition, for example, a packet. If both of them are sent and received at the same time in an exchange that accommodates both devices (when the call rate is increased), the buffer allocation for reception and the empty buffer allocated to the reception unit even if the transmission queue length is predetermined However, there is a problem that the condition of the delay time of the line device cannot be satisfied.

The present invention has been made in view of such drawbacks, and provides an excellent compound exchange capable of preventing an increase in delay time even between devices having severe transmission / reception time conditions.

(Means for Solving Problems) In a buffer management method that uses an HDLC procedure to send and receive information between devices and manages the number of allocated buffers that store the sent and received information, exchange of information between a terminal device and a processing device A receiving buffer allocating section having an allocation table for allocating a receiving buffer necessary for the transmission, a transmitting buffer allocating section having an allocation table for allocating a transmitting buffer necessary for transmitting and receiving information between the processing device and the terminal device, and a common buffer pool The management table that manages the number of empty buffers for each has a buffer management unit for managing the number of allocated reception buffers and the number of allocated transmission buffers. When the number of empty buffers falls below a certain amount, the allocation buffer for reception is This is a buffer management system characterized by reducing the number of buffers and the number of allocated buffers for transmission.

(Operation) The empty buffer number management unit manages the number of empty buffers in the common buffer pool, and increases or decreases the number of empty buffers by 3
Quantity management is performed by an empty buffer number management table that is detected in stages.

When the number of empty buffers in the common buffer pool becomes equal to or smaller than a predetermined number, the empty buffer number management unit detects the number, and issues a change instruction of the buffer allocation number to the reception buffer allocation unit to reduce the buffer allocation number.

If necessary, the transmission buffer allocation unit is also instructed to change the buffer allocation number to reduce the buffer allocation number.

(Embodiment) FIG. 1 is a system configuration diagram according to the present invention. In the figure, 10 is an exchange, 11 is a receiving unit, 12 is a processing unit, 13 is a transmitting unit, 14 is a common buffer pool, 15 is an empty buffer number management unit, 15 _-1 is an empty buffer number management table, and 16 is for reception. Buffer allocation unit, 16 _-1 is a variable buffer allocation table for line device, 16 _-2 is a variable buffer allocation table for packet device,
Reference numeral 17 is a transmission buffer allocating unit, 17 _-1 is a line device dispatch buffer allocation table, 17 _-2 is a packet device variable buffer allocation table 18, and 18 is a line device in which transmission / reception of information is performed according to the HDLC procedure. , 19 and 20 are packet devices whose transmission execution time conditions are loose. The present embodiment relates to the I interface recommended by CCITT as its main target using the HDLC procedure capable of multiple links. In the I interface, call processing information of the line device 18 and packet data are transmitted and received on Dch. User information such as voice and data of the line device 18 is Bc.
It is sent and received by h. Dch is LAPD (link acces
s procedure on the D channel)
In order to perform this processing using the HDLC signal system, it is necessary to store it in a temporary buffer during transmission and reception. The operation will be described below.

The empty buffer number management unit 15 uses the empty buffer number management table 15 _-1.
Manages the number of empty buffers in the common buffer pool 14. When the number of empty buffers is X or less, the instruction I for changing the variable buffer allocation table is given, when the number of empty buffers is Y or less, the instruction II is given, and the number of empty buffers is Z or less. In this case, the buffer management is performed by issuing the instruction III to the reception buffer allocation unit 16 and the transmission buffer allocation unit 17. The reception buffer allocator 16 is a line device
18 or the packet device 19 and the processing device 12 have a function of receiving information from the line device 18 or the packet device 19 and supplying a buffer to the receiving unit 11 to store the information when the information is exchanged. is there. The transmission buffer allocating unit 17 has a function of supplying a buffer for accumulating transmission information of the processing device 12 when the processing device 12 and the line device 18 or the packet device 20 transmit and receive information. Processor 12 Is returned to the common buffer pool 14 as an empty buffer.

One embodiment of the instructions I, II and III will be described in detail below.

When the number of empty buffers shown in the management table 15 _-1 of the empty buffer number management unit 15 is X + 1 or more, information is transmitted / received based on the number of allocated reception buffers and the number of allocated transmission buffers.

The number of empty buffers in the common buffer pool 14 has become X because the amount of information transmission between the line device 18, the packet device 19 and the processing device 12 and the amount of transmission between the processing device 12 and the packet device 20 have increased. When the management unit 15 detects it, the empty buffer number management unit 15 issues an instruction I to the reception buffer allocation unit 16. The state at this time is shown in FIG. The receiving allocation unit 16 is reduced by the instruction I issued from the empty buffer number management unit 15. This reduction does not uniformly reduce the line device buffer 16 _-1 and the packet device buffer 16 _-2 , but rather the line Since the device 18 executes the call processing control, it is immediate, while the packet device 19 is waiting and therefore it is necessary to make it easy to transmit the data of the line device 18. From 16 _-1 Packet device buffer
We will reduce 16 _-2 a lot. Therefore, with the instruction I, the number of allocation buffers of the variable buffer allocation table 16 _-2 is set to "2". Reduce to. If the variable buffer allocation table 16 _-2 does not become "2" or less due to the reduction in the number of allocated buffers, the reception buffer allocation unit 16 does not issue an empty buffer request to the empty buffer number management unit 15, so the common buffer pool This will limit the number of empty buffers to 14. Further, when there is a request from the receiving unit 11 to the receiving buffer allocating unit 16 for receiving and transmitting information between the line device 18, the packet device 19 and the processing unit 12, the receiving buffer allocating unit 16 receives more requests. Since 16 issues an empty buffer request to the empty buffer number management unit 15, it becomes impossible to instantly give an empty buffer to the reception unit 11. Therefore packet equipment
The variable buffer allocation table 19 controls the execution time from the reception unit 11 to the processing device 12.

Even after the instruction I is executed, the call volume does not decrease and the instruction II is issued when the number of empty buffers shown in the empty buffer number management table 15 _-1 of the empty buffer number management unit 15 becomes Y. This state is the fourth
Shown in the figure. Instruction II is the variable table 16 for the packet device 19.
_-2, the number of buffers in the variable table _17-2 for the packet device 20 of the transmitting buffer allocating unit 17 is also reduced, and the number of buffers in the variable table 17 _-2 for the packet device 20 in the transmitting buffer allocating unit 17 is reduced by the receiving buffer allocating unit 16 from the receiving unit 11 to the processing device 12 The execution time until the transmission unit 13 is notified from the processing unit 12 by the information of the transmission buffer allocation unit 17 is prioritized between the line unit 18 and the packet unit 19, and the data of the line unit 18 is compared to the packet unit 19. The immediacy of the line device 18 is maintained by facilitating transmission of the line device 18.

If the number of empty buffers in the empty buffer number management unit 15 decreases even after the execution of the instruction II, the instruction III is issued as shown in FIG. The instruction III is the management table 15 of the empty buffer number management unit 15.
_-1 is issued when the number of empty buffers becomes Z, whereby the receiving buffer allocating unit 16 causes the variable table 16 _-2.
Of the variable table 16 _-1 is set to "2" Reduce to. Further, the transmission buffer allocator 17 sets the variable table 17 _-2 to "zero", and the variable table 17 _-1 also allocates the buffer to "2". Reduce to.

This controls the number of buffer allocations of the receiving buffer allocator 16 and the number of buffer allocations of the transmitting buffer allocator 17 to satisfy the condition of the execution time from the reception of the information of the line device 18 to the transmission of the exchange 10. In addition, the information of the packet devices 19 and 20 can be transmitted.

That is, the immediacy of the line device 18 is maintained by making it easier to transmit the data of the line device 18 as compared with the packet devices 19 and 20.

It should be noted that the number of empty buffers and the number of buffer allocations, which are parameters, vary depending on each system.
It is not necessary to use up to all of III.

(Effect of the Invention) As described in detail above, according to the present invention, information is received by dynamically changing the receiving buffer allocation number and the transmitting buffer allocation number of the receiving unit according to the amount of empty buffers. It is possible to send and receive data without increasing the delay time even if a rotating device or the like having a strict time condition from the start to the transmission is connected.

That is, when the number of free buffers becomes a certain amount or less, the reception allocation buffer or the transmission allocation buffer is reduced, but the number of buffers from the packet device, which has a waiting time, is reduced more than that of the line device buffer which requires immediateness. As a result, it becomes possible to facilitate the data transmission of the line device and maintain its immediacy.

Since the present invention is a method of dynamically changing the number of empty buffers according to the amount of empty buffers, it is possible to directly manage the empty buffers by providing the processing device with the empty buffer number management function. Further, the present invention can obtain the same effect as the above not only in the case of being used for the exchange but also in the transmitting / receiving device such as VAN, LAN etc. for transmitting / receiving the information by the HDLC procedure.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a buffer management system according to the present invention, FIG. 2 is a configuration diagram of a conventional buffer management system, FIG. 3 is an explanatory diagram in the case of instruction I, and FIG. 4 is an explanatory diagram in the case of instruction II. Figure,
FIG. 5 is an explanatory diagram of the case of instruction III. 1,10 …… Switch, 2,11 …… Receiver, 3,12 …… Processing device,
4,13 …… Transmitter, 5,14 …… Common buffer pool, 6,16…
… Reception buffer allocation unit, 15 …… Empty buffer number management unit,
17 ... Transmission buffer allocation unit, _15-1 ... Empty buffer number management table, _16-1 , _16-2 ... Variable buffer allocation table, _17-1 , _17-2-2 ... Variable buffer allocation table.

Claims (3)

[Claims] 1. A buffer management system for managing the number of buffers allocated for storing transmission / reception information using an HDLC procedure for transmission / reception of information between devices, which is necessary for transmission / reception of information of a processing device connected to a line device and a packet device. A receiving buffer allocating means for allocating the receiving buffers for the line device and the packet device, and an empty buffer number managing means for managing the allocating number of the receiving buffers corresponding to the empty buffer number of the common buffer pool. A buffer management method, further comprising: when the number of empty buffers is equal to or less than a predetermined amount, the number of buffers for packet devices is further reduced from the number of buffers for line devices in the number of allocated buffers for reception. 2. A buffer management system for managing the number of allocated buffers for storing transmission / reception information using an HDLC procedure for transmission / reception of information between devices, which is necessary for transmission / reception of information of a processing device connected to a line device and a packet device. A transmission buffer allocating means for allocating transmission buffers for the line device and the packet device, and an empty buffer number management means for managing the transmission buffer allocation number corresponding to the number of empty buffers in the common buffer pool are provided. Then, when the number of empty buffers becomes a certain amount or less, the number of buffers for the packet device is reduced more than the number of buffers for the line device in the number of allocated buffers for transmission. 3. A buffer management system for managing the number of allocated buffers for storing transmission / reception information by using HDLD means for transmission / reception of information between devices, which is necessary for transmission / reception of information of a processing device connected to a line device and a packet device. Receiving buffer allocating means for allocating the receiving buffers for the line device and the packet device, transmitting buffer allocating means for allocating the transmission buffers for the line device and the packet device, and an empty buffer in the common buffer pool The number of allocated buffers for reception and the number of allocated empty buffers for managing the number of allocated transmission buffers corresponding to the number are provided, and when the number of empty buffers becomes a certain amount or less, the number of allocated buffers for reception And the number of allocated buffers for transmission, the number of buffers for the packet device is further reduced more than the number of buffers for the line device. Buffer management system according to claim.