JPS63132551A - Communication control unit - Google Patents

Abstract

PURPOSE:To simplify a line containing part and other device, and an interface condition by providing a buffer function in common to a transmitting/receiving means and a processing means of its outside, accumulating temporarily transmitting/receiving information in a first accumulating means, and saving it in a second accumulating means from the first accumulating means, when said information comes not to satisfy a prescribed condition. CONSTITUTION:A buffer memory 54, and a large capacity buffer 62 are provided as temporary accumulating places of transmitting/receiving information, separately in accordance with an opposed device in a data link layer L2, and in a network layer L3 in common to (n)+1 pieces of data link layers L2, respectively. In this state, information having a property by which a scale of information to be buffered is determined peculiarly to a system is stored in a buffer memory 54 of the data link layer L2. Also, information having a property determined by a kind of a communication protocol to be supported and an opposed device, etc., is stored in the large capacity buffer 62 provided on the outside of the data link layer L2. In such a way, the capacity of the buffer memory 54 in the data link layer L2 can be reduced, and also, the simplicity of an interface of the data link layer L2 and the network layer L3 can be held.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a communication control device, and more specifically, a communication control device that performs communication with a counterpart device using an advanced data link protocol such as a high-level data link control procedure. This invention relates to a control device, and in particular to a management method for a buffer that temporarily stores information.

(Prior Art) In a conventional communication control device, a common control system performs multiple control of a plurality of line accommodation units each connected to a plurality of opposing devices through lines. For example, "Technology Transfer Special Seminar Text iF Packet Switching Network" published by Japan Communication Technology Co., Ltd.
On pages 23-24 (March 11385), such a communication control device is described.The control system is provided with a processing device and a main storage device, and these and a line storage unit are connected to a common bus. The right to use the bus is assigned by the arbiter.

In this type of device, information exchanged with the opposing device is temporarily stored in a buffer area of the main storage device. More specifically, the information to be sent from the processing device to a specific opposing device via the line accommodation section is stored in the buffer area of the main storage device, and after the first line accommodation section sets up a link with the opposing device, it is sent to the specific opposing device. Send to the opposite device while reading from the storage device.

The buffer area storing the transmitted information is released after receiving the delivery confirmation from the opposite device.

Further, a specific line accommodation unit that receives information from the opposite device requests the processing device to allocate a buffer area in the main storage device. Generally, there are many methods in which a buffer area is allocated in advance.

When the line accommodation section stores, for example, one frame worth of information in the buffer area, the management authority for that area is delegated to the processing device, and the processing device then executes necessary processing on this information.

In this way, in conventional communication control devices, a buffer area for temporarily storing transmitted and received information is provided in the main memory of the control system, which is outside the line storage unit that exchanges information with the opposing device, and its management is also performed by the control system. This was done using a processing device.

(Problems to be Solved by the Invention) However, the temporary storage of transmitted and received information and the transmission and reception operations are originally a series of operations that are closely related to each other. Therefore, in the conventional method, where the temporary storage area of information is managed by a control system other than the line storage unit that actually sends and receives information,
The distribution of functions between the line accommodation section and the control system, as well as the interface conditions between the two, had become complicated.

In order to solve this problem, it is conceivable to simply provide a buffer in each line accommodation section. However, in such a configuration, there is a loss in dividing the buffer area, and a swarm effect on traffic cannot be expected. Therefore, the equipment as a whole is much more efficient than the conventional system in which buffer areas are centrally allocated in the control system. Requires large storage capacity.

It is an object of the present invention to eliminate such drawbacks of the prior art and to provide a communication control device in which the division of functions and interface conditions between a line accommodation section and other devices, especially devices on a higher level thereof, are simplified. .

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a buffer function for temporarily storing information to be sent to and received from the opposing device into a functional part that actually combines the sending and receiving. In addition to the above, they are also placed in common areas outside the building, and both are used depending on predetermined conditions.

This makes it possible to obtain the swarm effect of buffer functions, and also eliminates the problems that would arise if buffer management and information transmission and reception operations were performed in separate functions.

According to the present invention, a plurality of transmitting/receiving means each connected to a line to the opposite device and transmitting/receiving information to/from the opposite device according to a predetermined transmission control procedure; In a communication control device, the plurality of transmitting/receiving means each include a processing means for processing information transmitted/received to/from an opposing device, and a connecting means for commonly connecting a plurality of transmitting/receiving means to the processing means. The processing means includes a first storage means for temporarily storing transmission/reception information for a corresponding opposite device, and the processing means is a second storage means for temporarily storing transmission/reception information for any one of the opposite devices, which is commonly used by the plurality of transmission/reception means. The first storage means temporarily stores the transmitted and received information that satisfies a predetermined condition, and the second storage means temporarily stores the transmitted and received information that satisfies a predetermined condition among the transmitted and received information stored in the first storage means. Those that no longer satisfy predetermined conditions are evacuated. This predetermined condition is set so that the amount of transmitted and received information stored in the first storage means does not exceed the storage capacity of the first storage means.

(Function) According to the present invention, the buffer mechanism for temporarily storing information to be transmitted and received to the opposing device is provided in the transmitting and receiving means that actually performs transmission and reception, and is also common to the processing means external to the transmitting and receiving means. It is deployed in Transmission/reception information is temporarily stored in the first storage means, but if it no longer satisfies a predetermined condition, the information is stored in the first storage means.
from the storage means to the second storage means.

Note that in this specification, the term "transmission and reception" is interpreted to have an optional meaning including at least one of transmission and reception.

(Example) Before entering into a detailed description of the present invention, an example of a conventional method will be described with reference to FIG. 3 in order to facilitate understanding thereof. This is the communication control device described in the above-mentioned "Packet Switched Network" published by Japan Communication Technology Co., Ltd., pages 23-24.In the communication control device IO, there are a plurality of N lines each accommodating a plurality of lines 12 to a plurality of opposing devices. 0 line accommodation FsLIJ1~ where the line accommodation units LUI~LUX are multiple controlled by a common control system
The LIJN is a line termination device that is connected oppositely to a portion corresponding to the line accommodation section of the opposing device and controls setting up a data link using an advanced transmission control procedure such as HDLC.

The control system includes a processing unit ff1CP and a main storage device M, and these and the line storage unit Ltll NLUN share a common path 14.
It is continued in ta. The right to use bus 14 is 7-vita 1.
At B, it is allocated between the line accommodation units LUI to LUX, the processing device CP, and the main memory gl port. Main storage M
In addition to storing the programs of the processing device CP, a buffer area is also provided for temporarily storing information sent and received with the opposing device.

When transmitting information that has been processed by the processing device CP to the opposite device via the line accommodation unit LUI, for example, it is stored in the buffer area of the main storage unit 1IN, and the information transmission is transmitted to the line accommodation unit LUI. Request to LUI. This request is written in the form of a command in the main memory M in this conventional example. When the 0 line accommodation unit LUI reads this command, it sets up a link with the opposite device according to the HDLC procedure, and sends this request from the main memory NN. Read the information and send it to the opposite device. When the transmission is completed and a delivery confirmation signal is received from the opposite device, the line accommodation unit Lul notifies the processing device CP to that effect. In response, the processing device
Release the buffer area containing the sent information.

For example, when the line accommodation unit LUI receives information from the opposite device, the line accommodation unit LUI requests the processing unit @CP to allocate a buffer area of the main storage device H. Generally, when the 0-line accommodation unit LUI, which has been allocated a buffer area in advance, receives information from the opposite device and stores one frame's worth of information in the buffer area, it sends a message to that effect to the processing unit fiCP. The processing device CP is notified and the management right of the area is delegated to the processing device CP. The processing unit ICP then performs the necessary processing on this information.

In this way, in the conventional communication system a device IO, a buffer area for temporarily storing transmitted and received information is provided in the control system's main storage device IN, which is external to the line accommodation unit LUI-LtlN that exchanges information with the opposing device. The processing equipment CP also provides and manages the processing equipment.
It was done at

Next, an embodiment of a communication control device according to the present invention will be described in detail with reference to FIG. The communication control device in this embodiment has seven layers (as) of open system interconnection (as■).
layer), that is, the physical layer L1. In this embodiment, the physical layer L1 and the data link layer L2 are arranged one-to-one with the opposing device, and constitute a line-compatible transmitting and receiving function section. . However, the network layer L3 has multiple (
It takes the form of a processing function unit that is commonly disposed for the combinations of layers L1 and L2 of n+1) sets and performs multiple processing on them.

Among such configurations, the part that is particularly targeted by the present invention is the part that includes (n+1) data link layers L2 and the L3 processing device 150 that interfaces therewith. These parts will be explained in detail below.

The data link layer L2 has a transmitter/receiver section 52, and is connected to the opposite device by a line 12 via the corresponding physical layer L1. The transmitting/receiving unit 52 is a functional unit that performs an operation of transmitting and receiving information with the opposite device via the physical layer L1 according to an advanced transmission control procedure such as HDLC.

The data link layer L2 is provided with a buffer memory 54 that temporarily stores this transmitted and received information. Necessary control such as allocation of the buffer area is performed by a buffer memory control unit (BMC) 5B. Each component of the data link layer L2, such as the transmitter/receiver 52 and the buffer memory controller 56, is controlled by the L2 controller 58.

This combines high-level processing such as order control of the data link layer L2.

In this embodiment, an L3 processing device 50 is provided that combines processing of one network layer L3 provided in common with (n-1) data link layers L2. A large capacity buffer 62 and an L2/L3 transfer device 84 are connected to the L3 processing device 50 via an L3 processing system (P) bus 80, and the L2/L3 transfer device 64 is connected to the L2/L3 transfer bus 6.
(n+1) data link layers L20 to L2 by B
n in common. The large-capacity buffer 62 is a buffer device that temporarily stores information transmitted and received with the opposing device. The L2/L3 transfer device 84 is a functional unit that controls the transfer of information between the data link layer L2 and the network layer L3.

As will be explained, in this embodiment, there are buffer memories 54, which are individually arranged for corresponding devices in the data link layer L2 as temporary storage locations for transmitted and received information, and (n+1
) data link layers and a network layer L common to 2.
A large capacity buffer 62 provided in 3 is provided.

The operation of transmitting and receiving information to and from the opposite device is actually performed in the data link layer L2. So basically,
It is preferable that the data link layer L2 manages the buffer that temporarily stores the transmitted and received information, but in this embodiment, the two buffers 54 and 82 are used differently as follows. That is, information whose size of information to be buffered is determined uniquely to the system is stored in the buffer memory 54 of the data link layer L2, and information such as the types of communication protocols supported and the results of negotiation of communication settings with the opposing device are stored. Information of the nature determined by is configured to be stored in a buffer outside the data link layer L2, that is, in the large capacity buffer 82 in this embodiment.

Originally, when transmitting information to the opposite device, the information to be buffered includes information to be transmitted and information currently being transmitted, as well as information for which transmission has been completed but no delivery confirmation signal has been returned.

As is well known, it is generally accepted that the delivery confirmation signal is sent together for multiple units of received information. The range to be summarized is determined during initial negotiation during link establishment. For example, the protocol according to CCI TT Recommendation In this case, for example, if 4 bytes are included in an l frame, a situation may arise in which a maximum of about 500 bytes of information are waiting for receipt of a delivery confirmation signal. Also, for example, in LAP-D that complies with the CGI Recommendation I series.

A logical maximum of approximately s, ooo links is allowed to be set up on one line.

In this way, for the information waiting for receipt of the delivery confirmation signal,
A fairly large capacity buffer area must be secured.

As we will see below, the size of the transmission information buffer is determined uniquely depending on the system, and also depends on individual conditions such as the type of communication protocol supported and the result of negotiation of communication settings with the opposite device. There are things determined by

Moreover, in the latter case, the size of the buffer to be prepared varies greatly depending on the determined parameters.

In this embodiment, we focused on this feature, and the former information is as follows.

The information is stored in the functional part that actually connects transmission and reception, that is, the buffer memory 54 in the data link layer L2, and the latter information is saved and stored in a buffer outside the data link layer L2, that is, the large capacity buffer 82. It consists of

In this case, the issue is when to save the information.

The buffer release timing and the range of information to be saved are 0. In this embodiment, as a solution to this problem, the information sent to the opposing device is sent to the opposing device for a predetermined period specified by the above-mentioned timer. A system is adopted in which those whose arrival is not confirmed are saved in the large-capacity buffer 82.

For example, for a counterpart device that is configured to send back a delivery confirmation signal for up to 127 frames of received information all at once, 127 such timers are prepared in the L2 processing unit 58 of the data link layer L2 connected to it. Ru. As shown in FIG. 2, the L2 processing unit 58 sequentially starts corresponding timers each time one frame of information is sent out. When the opposing device receives all 127 frames of information, it sends back an arrival confirmation signal, but the example in Figure 2 shows a case where the corresponding timer times up to the 2nd frame, which is smaller than this. ing.

When the time has expired, the L2 processing unit 58 notifies the L3 processing unit 50 of this fact, and the L3 processing unit 50 uses the large capacity buffer 6.
2. Secure a storage area for time-up information. The timed-up information is sequentially read from the buffer memory 54, transferred to the large capacity buffer 62 by the L2/L3 transfer device W164, and stored therein.

Those areas of buffer memory 54 are freed up for others.

In this way, a large capacity buffer 62 of time-up information is stored.
evacuation will be carried out.

However, in this example, 1 from the (k+1)th frame
Information up to the 27th frame is stored in the buffer memory 54.
The delivery confirmation signal is returned from the opposite device before the timer times out while the delivery confirmation signal is being held at the same time.

Therefore, those areas of the buffer memory 54 are released upon reception of the delivery confirmation signal, and the timers are also reset.

As described above, the buffer memory 54 and the large capacity buffer 6
Regarding the usage of 2, we have considered the case where the latter is used as non-delivery confirmation information as a condition, but the following can also be considered as other cases.

As described above, in the case of LAP-D, a plurality of links can be set on the same line, and they are distinguished by the value of the address part. For example, in a system where two links are established and one link performs delivery confirmation for each frame, and the other link performs delivery confirmation for multiple frames (for example, up to 7 frames), the buffer size will be greatly affected as in the latter case. It is also possible to save all link information to the large-capacity buffer 62 and not to save information that does not significantly affect the buffer size from the buffer memory 54. It may be configured to save information about the link to be used. For example, if the frame of one link is 280 bytes and the frame of the other link is 4 bytes, only the latter may be saved. good.

As for the buffer outside the data link layer L2, that is, the large-capacity buffer 62, it is preferable to deploy one system in common for a plurality of (n+1) data link layers L2 as in this embodiment, and its management is performed using a swarm effect. Dynamic management is desirable, but dynamic management introduces control complexity. Therefore, it ultimately depends on the trade-off between the two features.

In this embodiment, the L2/L3 transfer bus 66, the L3P bus 60, and each device are connected in the form of a bus connection. In the case of these bus connections, particularly in the former case, the L2/L3 transfer device 64 having an arbiter function is used to manage the right to use the bus.

In this way, in this embodiment, in addition to providing a buffer function for temporarily accumulating information to be transmitted and received to the opposite device in each data link layer L2 that actually connects the transmission and reception, the buffer function is provided in multiple data link layers externally. It is also deployed in the network layer L3, which is shared by L2. As a result, the capacity of the buffer memory 54 in the data link layer L2 can be reduced, and the simplicity of the interface between the data link layer L2 and the network layer L3 can be maintained.

(Effects of the Invention) According to the present invention, for example, the 4777 function for temporarily storing information to be transmitted and received to the opposing device is provided in the machine section that actually performs transmission and reception, and also in the external device. They are also installed in common areas. Therefore, the capacity of the buffer in the transceiver part is small, yet the simplicity of the interface between the two parts is maintained.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing an embodiment in which the communication control device according to the present invention is applied to the lower three systems of open system interconnection, and FIG. 2 shows an example of buffer saving in the embodiment shown in FIG. FIG. 3 is a system configuration diagram showing an example of a conventional communication control buffer management method. Main parts 50, L3 processing device 51, transmitting/receiving section 54, buffer memory 5G, buffer memory control section 5B, L2 processing section 80.138. , Bus 62...Large capacity/<Tuffa 84 , , , L2/L3 transfer device patent applicant Oki Electric Industry Co., Ltd. Agent Takao Kamasu Oo Maruyama 2 〒

Claims (1)

[Scope of Claims] A plurality of transmitting/receiving means each connected to a line to the opposite device and transmitting/receiving information to/from the opposite device according to a predetermined transmission control procedure, and via any of the plurality of transmitting/receiving means. In the communication control device, the plurality of transmitting and receiving means each include a processing means for processing information transmitted to and received from a corresponding opposing device, and a connection means for commonly connecting the plurality of transmitting and receiving means to the processing means. , a first storage means for temporarily accumulating transmission/reception information for an opposing device corresponding to the transmitting/receiving means; The first storage means temporarily stores information that satisfies preset conditions depending on the amount and nature of the information, and the second storage means temporarily stores the transmitted and received information. The communication control device is characterized in that out of the transmission and reception information stored in the first storage means, information that no longer satisfies the condition is saved.