JPH06276254A - Communication control equipment - Google Patents

Abstract

PURPOSE:To provide communication control equipment capable of dynamically selecting a network replying to QOS(quality of service) requested by a high-order layer and efficiently performing communication control. CONSTITUTION:The network can be selected corresponding to the fluctution of the QOS requested by an application by providing a QOS table 21, and a communication control part 22 which selects the network in accordance with the quality of service requested by the high-order layer by referring to the QOS table 21 are provided at a transport layer control part 2 in the communication control equipment provided with a high-order layer control part and the transport layer control part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device for performing communication based on a hierarchical network architecture such as OSI.

[0002]

2. Description of the Related Art In data communication based on OSI, upper layers (5th, 6th and 7th layers) use communication functions provided by a transport layer (4th layer) and below to perform file transfer, mail transfer, etc. Providing communication applications.
Further, the network layer (third layer) and below are defined for each network such as a packet switching network and ISDN, and provide a communication function according to the network type. In addition, the transport layer uses the communication function provided by the network layer, and provides a common communication function independent of the network to upper layers. In addition, one of the functions of the transport layer is to absorb the difference in the service quality of communication in the lower network.

In OSI, the upper layer can specify the quality of service (QOS) of communication such as throughput and delay, and request the QOS provided by the transport layer. At this time, the transport layer requests the requested QO.
In order to satisfy S, it is necessary to perform communication control.

(References) (1) JIS X 5003 Basic reference model for open type system connection, issued by Japan Standards Association (2) JIS X 5003 Reference WAN lower layer implementation rules, issued by Japanese Standards Association (3) JIS X 5005 Basic reference model for open system connection-Name and address assignment method, published by Japanese Standards Association

[0005]

However, how to select the network based on the requested QOS is not specified in the standard or the implementation contract, and the QOS is reflected in the actual communication control. I couldn't do that. Although the usage method of QOS has been a subject of standardization in the future, a concrete realization method has not been proposed yet. Therefore, conventionally, system generation (S
In G) and the like, there is no choice but to fixedly set the network used for each application.

In view of the above-mentioned conventional problems, an object of the present invention is to provide a communication control device which dynamically selects a network according to a QOS required by an upper layer and enables efficient communication control. To do.

[0007]

In order to achieve the above object, the present invention has a network control unit for controlling communication according to a network type, a transport layer control unit for controlling communication between end systems, and a transport. In a communication control device having an upper layer control unit for controlling communication higher than a layer, a transport layer control unit controls a QOS for managing service quality for each network.
A communication control device provided with a communication control unit that selects a network according to the quality of service requested from an upper layer by referring to the table and the QOS table is proposed.

[0008]

According to the present invention, when the QOS is specified by the upper layer, the communication control unit refers to the QOS table and selects an appropriate network corresponding to the QOS.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an outline of the communication control device of the present invention.
In the figure, 1 is an upper layer control unit (UC), 2 is a transport layer control unit (TC), 3-1, 3-2, ...
n is a network control unit (NC), 4-1, 4-2, ...
4-n are communication lines compatible with various networks such as a packet switching network and ISDN.

The upper layer control unit 1 controls communication above the transport layer (4th layer) (5th, 6th and 7th layers). The transport layer control unit 2 controls communication between end systems, and includes a QOS table 21 and a communication control unit 22 as shown in FIG. The network control units 3-1 to 3-n are communication lines 4-1 to 4-1 respectively.
The communication control corresponding to 4-n is performed according to the network type.

The QOS table 21 manages the quality of service for each network, and its contents are, as shown in FIG. 3, network addresses NA1, NA2, NA3 ,. Network type that represents the type of network that is supported and quality of service (QOS) of each network
And a QOS parameter that represents Note that the QOS parameters here consist of throughput (THP), transfer delay (TD), and communication cost (C).

Further, the communication control unit 22 refers to the QOS table 21 and selects a network according to the QOS requested by the upper layer. The flow of the processing is shown in FIGS. 4 and 5.

Next, the operation for starting communication based on the communication connection request from the upper layer control unit 1 will be described with reference to FIG.

First, it is assumed that UC1 requests the start of connection to TC2, and also passes the transport address and the requested QOS (step S1). As shown in FIG. 6, the transport address comprises a transport selector and a network address list, and a plurality of network addresses NA1, NA3, ... Are written in the network address list.

In TC2, the communication control unit 22 uses QOS
With reference to the table 21, a network satisfying the requested QOS is searched for among the networks specified by the network address included in the transport address (step S2).

At this time, if there is a suitable network (step S3), the communication control unit 22 selects the network, that is, the NC corresponding to the network, and establishes the connection below the transport layer (step S4). ). Then, communication between upper layers is started (step S5) and further ended (step S6).
Then, the connection below the transport layer is released (step S7).

On the other hand, if there is no compatible network,
The communication control unit 22 notifies UC1 that there is no compatible network (step S8).

In the above operation, the connection below the transport layer is released in step S7. However, if the application in the upper layer wants to perform communication again, the connection may be continued without releasing the connection. After the notification in step S8, the application requests the requested QO.
The condition of S may be weakened and a connection request may be made again.

Next, the operation when there is a change in the QOS required by the UC1 or a change in the network performance will be described with reference to FIG.

First, the QOS of the application during communication
Requirements for UC1 change and UC1 TCs another QOS
It is assumed that the QOS value in the QOS table 21 is changed due to a change in the performance of the network that is requested by No. 2 or during communication (step SP1).

In TC2, the communication control unit 22 uses the QOS
The table 21 is referred to search for a network satisfying the requested QOS (step SP2).

At this time, if there is a suitable network (step SP3), it is further checked whether or not the network is the same as the one being connected (step SP4). If they are the same, the communication is continued (step SP5). Further, when the communication is completed (step SP6), the connection below the transport layer is released (step SP7).

On the other hand, when the compatible network is different from the one being connected, in order to reselect the network, the connection below the network layer is released,
Communication between upper layers and between transport layers is interrupted (step SP8). However, in the case of connectionless type, release is not necessary.

Next, a new network is selected, that is, an NC corresponding to the network is selected, and a connection below the transport layer is established (step SP).
9). Even in the connectionless type, the network is controlled so that it can be used.

Then, the communication between the upper layers and between the transport layers is restarted on the new network connection (step SP10).

On the other hand, if there is no compatible network, the communication control unit 22 notifies the UC1 that there is no compatible network (step SP11).

In the above operation, the connection below the transport layer is released in step SP7. However, if the application in the upper layer wants to perform communication again, the connection may be continued without releasing the connection. Also,
After the notification in step SP11, the application may weaken the required QOS condition and make a connection request again.

[0028]

As described above, according to the present invention, even if the QOS requested by the application or the QOS provided by the network changes, the network that automatically meets the QOS condition in the transport layer can be provided. You can choose, you can communicate efficiently,
In particular, it is possible to select an appropriate network according to the demands of various applications such as a change in data transfer amount and a change in communication urgency. In addition, recently, networks having various qualities such as ISDN and frame relay have become available, and according to the present invention, application is made by effectively utilizing such network services with various qualities. Can communicate between.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a communication control device of the present invention.

FIG. 2 is a configuration diagram of a transport layer control unit.

FIG. 3 is a diagram showing the contents of a QOS table.

FIG. 4 is a flowchart of processing when communication is started based on a communication connection request from an upper layer control unit.

FIG. 5 is a flow chart of processing when there is a change in QOS or a change in network performance required by an upper layer control unit.

FIG. 6 is a diagram showing the structure of a transport address.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper layer control part, 2 ... Transport layer control part, 3-1 to 3-n ... Network control part, 4-1 to 4
-N ... communication line, 21 ... QOS table, 22 ... communication control unit.

Claims (1)

[Claims] 1. A network control unit for performing communication control according to a network type, a transport layer control unit for performing communication control between end systems, and an upper layer control unit for performing communication control above the transport layer. In the communication control device, the transport layer control unit includes a QOS table that manages the quality of service for each network and a communication control unit that refers to the QOS table and selects a network according to the quality of service requested from an upper layer. A communication control device comprising.