JP3183678B2 - Communication control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control method,
OSI (OpenSystem) especially in terminals and exchanges
ms Interconnection) is a communication control according to a hierarchical configuration according to a reference model, combining a data link procedure that operates autonomously independently of the connection establishment of an upper layer and the above-described layer procedure of returning a response to the data link after the connection is established, The present invention relates to a communication control method for performing communication.

[0002]

2. Description of the Related Art A widely used data link communication control method in a terminal or an exchange is to autonomously respond to a data link setting request or a disconnection request irrespective of an upper layer (network layer or higher) connection setting. Executing and establishing a data link are performed independently of the upper layer (network layer or higher).

FIG. 7 is a flowchart showing an example of a conventional data link communication control procedure. In FIG. 1, the exchange 2 receives a data link establishment request signal 5 from the terminal 1, and the data link layer processing unit 3 executing the data link procedure in the exchange 2 autonomously returns a data link setting response 6, The data link is established, and a data link establishment notification 7 is sent to the upper network layer processing unit 4.

FIG. 8 shows a data link communication control method which is expected to spread in the future. In response to the data link establishment request signal 5, the data link layer processing unit 3 sends a data link establishment notice 6 to the network layer processing unit 4, and the network layer processing unit 4 receives the connection setting response 8 from the upper layer. , A data link setting response 9 is returned to the data link layer processing unit 3.

[0005]

Therefore, when an LSI or software supporting the data link communication control method shown in FIG. 7 is used and a communication control method of a network layer or higher shown in FIG. 8 is used, the following is required. Problems arise.

In some cases, a frame is lost.
9) Immediately after the data link layer processing unit 3 receives the data link establishment request signal 5 from the terminal 1, when the information frame 11 is received, the network layer processing unit 4 is establishing a connection until returning the connection setting response 14. State 10
Therefore, if an information frame is received during this time, the data is discarded 12 due to state mismatch and the frame is lost.

In response to a data link establishment request,
When the data link layer processing unit 3 receives the data link establishment request signal 11 from the terminal immediately after the data link layer processing unit 3 receives the data link disconnection request signal 5 from the terminal 1, the network layer processing unit 4 Until the connection disconnection response 15 is returned, the connection is in the disconnection state 10, and if the data link establishment notification 12 is received during this time, the state will be inconsistent and the data link will not be established.

According to the present invention, in a communication system of a terminal or an exchange which realizes communication control in a hierarchical configuration according to the OSI reference model, a data link is established when a connection of an upper layer which is expected to spread in the future is established. A data link communication method widely used at present which performs a communication control method of a network layer or more to be set and a data link procedure autonomously, and establishes a data link independently of an upper layer (a network layer or more). It is an object of the present invention to provide a communication control method capable of solving the problems that data is lost or a data link cannot be established when a control method is connected and communicated on a terminal or an exchange.

[0009]

According to the present invention, in a communication system of a terminal or an exchange which realizes communication control in a hierarchical configuration according to an OSI reference model, a data link is established when a connection of an upper layer is established. A communication control function of a network layer to be set, a data link communication control function of executing a data link procedure autonomously, and performing a data link establishment and the like independently of a connection establishment of an upper layer (a network layer or more); The interface section was set during.

[0010]

The above interface implements the following functions. (1) When receiving a data link establishment notification from the data link layer and sending the data link establishment notification to the network layer, and receiving an information frame or the like from the data link layer until a connection establishment response is received from the network layer. In the interface unit, a signal such as a received information frame is held until a connection establishment response is received from the network layer, and upon receiving the connection establishment response from the network layer,
The held signal is sent to the network layer.

(2) After receiving a data link disconnection notification from the data link layer and sending the data link disconnection notification to the network layer, a data link establishment notification is sent from the data link layer until a connection disconnection response is received from the network layer. Received a data link establishment notification, etc., at the interface unit until a connection disconnection response is received from the network layer, and held upon receiving the connection disconnection response from the network layer. It sends a data link establishment notification and the like to the network layer.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing a communication mode in which communication between a terminal and a switch is exemplified. In FIG. 3, 1 is a terminal, 2
Is an exchange, and is a communication system according to the OSI reference model.

FIGS. 1 and 2 respectively show the XIT of the CCITT international standard between a terminal and an exchange. It is a flowchart which shows the communication example concerning this invention at the time of communicating by 25 procedures. Hereinafter, description will be made in order.

FIG. 1 is a flow chart showing an example of communication at the time of a data link establishment request between the terminal 1 and the exchange 2. The data link layer processing unit 3, the interface unit 4, and the network layer processing unit 5 It constitutes the control unit.

A data link establishment request (S
When the exchange 2 receives the (ABM) signal 6, the data link layer processing unit 3 of the exchange 2 autonomously returns a data link establishment response (UA) signal 7 to the terminal 1, and the data link layer processing unit 3 Indicates the data link establishment state 8
Becomes Further, the data link layer processing unit 3 sends a data link establishment notification 9 to the interface unit 4, and the interface unit 4 sends a data link establishment notification 10 to the network layer processing unit 5. The network layer processing unit 5 enters the state 11 of establishing connection with the upper layer. When the connection with the upper layer is completed, a connection establishment completion notification 12 is notified to the interface unit 4.

By the time the interface unit 4 receives the connection establishment completion notification 12 from the network layer processing unit 5, the data link layer processing unit 3
When the information frames 13 and 14 are received from the network layer processing unit 5, the information frames 13 and 14 are transmitted to the interface unit 4. Are maintained in the interface unit 4 while maintaining the order.

When the connection establishment completion notification 12 is returned from the network layer processing unit 5 to the interface unit 4, the interface unit 4 transmits the held information frames 13 and 14 to the network layer processing unit 5.

FIG. 2 is a flowchart showing an example of communication at the time of a data link disconnection request between the terminal 1 and the exchange 2. The data link layer processing unit 3, the interface unit 4, and the network layer processing unit 5 It constitutes the control unit.

When the exchange 2 receives a data link disconnection request (DISC) signal 6 from the terminal 1, the exchange 2
The data link layer processing unit 3 autonomously returns a data link disconnection response (UA) signal 7 to the terminal 1, and the data link layer processing unit 3
Becomes In addition, the data link processing unit 3 sends a data link disconnection notification 9 to the interface unit 4, and the interface unit 4 sends a data link disconnection notification 10 to the network layer processing unit 5. The network layer processing unit 5
The state 11 indicates that the connection with the upper layer is being disconnected. When the connection with the upper layer is completed, the connection disconnection notification 12 is sent to the interface unit 4.

When the data link layer processing unit 3 receives the data link establishment request (SABM) signal 13 from the terminal 1 before the interface unit 4 receives the connection disconnection completion notification 12 from the network layer processing unit 5, the interface unit 4 , The interface unit 4 holds the data link establishment request 13 in the interface unit 4 until receiving the connection disconnection completion notification 12 from the network layer processing unit 6.

When the connection disconnection completion notification 12 is returned from the network layer processing unit 3 to the interface unit 4, the interface unit 4 transmits the held data link establishment request 13 to the network layer processing unit 5.
Send to

FIG. 4 is a block diagram showing the configuration of a communication control unit in the exchange, which comprises a data link layer processing unit 3, an interface unit 4, and a network layer processing unit 5. A data link layer corresponding unit 41 for processing an interface with the layer processing unit 3 and a network layer corresponding unit 4 for processing an interface with the network layer processing unit 5
It consists of two.

FIG. 5 is a diagram showing a processing flow of the data link layer corresponding unit 41 in the interface unit 4. As shown in the figure, when the data link layer corresponding unit 41 receives a frame from the data link layer processing unit 3,
When the state in the interface unit 4 is the data link establishment state or the data link disconnection state, the reception unit waits for a reception frame in the waiting queue in the interface unit 4. When the state in the interface unit 4 is not the data link establishing state or the data link disconnecting state,
If the reception notification is a data link establishment request, it is set to the data link establishment state. In the case of a data link disconnection request,
Set to data link disconnected state. Then, it notifies the network layer processing unit 5 of the received frame.

FIG. 6 is a diagram showing a processing flow of the network layer corresponding unit 42 in the interface unit 4. As shown in the figure, when the notification information is received from the network layer transmission processing unit 5, if the notification information is a connection setting response, the network layer corresponding unit 42 stores the frame held in the waiting queue in the interface unit 4. Is sent to the network layer processing unit 5 to cancel the data link establishment state. If the notification information is a connection disconnection response, the frame held in the queuing queue in the interface unit 4 is transferred to the network layer processing unit 5.
To release the data link disconnected state.

[0025]

As described above, according to the communication control procedure of the present invention, the following results can be obtained in the communication control method. It is not necessary to modify the data link communication control procedure that is autonomously realized independently of the operation of the upper layer. It is not necessary to modify the communication control procedure of the network layer or higher that always checks the connection setting of the upper layer.

The data link communication control procedure that is autonomously realized independently of the operation of the upper layer and the communication control procedure of the network layer or higher that always checks the connection setting of the upper layer are combined to create a problem such as data loss. And a communication control procedure according to the OSI reference model can be realized.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a communication control method according to the present invention when a data link establishment request between a terminal and an exchange is made.

FIG. 2 is a flowchart showing one embodiment of a communication control method according to the present invention when a data link disconnection request between a terminal and an exchange is made;

FIG. 3 is a block diagram showing a communication form by taking communication between a terminal and an exchange as an example.

FIG. 4 is a block diagram showing a configuration of a communication control unit in the exchange.

FIG. 5 is a chart showing a processing flow of a data link layer corresponding unit in the interface unit.

FIG. 6 is a chart showing a processing flow of a network layer corresponding unit in the interface unit.

FIG. 7 is a flowchart showing an example of a conventional data link communication control procedure.

FIG. 8 is a flowchart showing a data link communication control method expected to spread in the future.

FIG. 9 is a flowchart illustrating a case where a frame is lost in the related art.

FIG. 10 is a flowchart showing a case where a data link is not established in response to a data link establishment request in the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Terminal, 2 ... Exchange, 3 ... Data link layer processing part, 4 ... Interface part, 5 ... Network layer processing part

Claims (2)

(57) [Claims] 1. A communication system for connecting a terminal and an exchange, between terminals or an exchange via a network, and performing communication control according to a hierarchical configuration according to an OSI reference model, comprising: a data link layer processing unit and a network layer processing unit for the OSI reference model; An interface unit is provided between the units, and after the data link establishment response is returned by the data link layer processing unit in response to a data link establishment request from a terminal or an exchange, the data is transmitted until a connection establishment completion notification signal is received from an upper layer. A communication control method comprising: holding a frame received by a link layer processing unit in the interface unit; and transmitting the held frame to an upper layer after receiving a connection establishment completion notification from an upper layer. 2. A communication system in which a network is connected between terminals and exchanges, between terminals or exchanges, and communication control is performed in accordance with a hierarchical configuration according to an OSI reference model, wherein a data link layer processing unit and a network layer processing of the OSI reference model are provided. An interface unit is provided between the units, and after the data link disconnection response is returned by the data link layer processing unit in response to a data link disconnection request from a terminal or an exchange, the data link disconnection completion notification signal is received from an upper layer. The new data link establishment request received by the link layer processing unit is held by the interface unit, and after receiving the connection disconnection completion notification from the upper layer, the held data link establishment request is sent to the upper layer. Communication control method.