JPH05260124A - Call control system - Google Patents

Abstract

PURPOSE:To provide the call control system which resolves defects of connection-oriented communication as well as connectionless communication. CONSTITUTION:A call is set by connection-oriented call control at the time of the start of communication (S14 to S17) After completion of this call setting, the control is switched to connectionless call control to perform the call control. That is, data transfer is immediately executed without call setting when a data communication terminal desires data transfer (S18 and S19). However, the call is automatically disconnected if data communication conforming to the connectionless call control is not continuously executed for a prescribed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call control system in data communication using a switching network (for example, public network).

[0002]

2. Description of the Related Art Conventionally, there are a connection-oriented communication and a connectionless communication as a communication mode in a network. Hereinafter, these will be described in order.

(1) Connection-Oriented Communication FIG. 2 shows the flow of call control in the connection-oriented communication mode.

In FIG. 2, an upper layer LU (which is called a transport layer or higher) higher than the network layer (layer 3) L3 issues a connection request to the network layer L3 (S).
1) In response, the network layer L3 issues a connection request to the network NT side (S2).
When the network layer L3 receives the establishment response from the network NT side (S3), a connection is established to the upper layer LU (S3), and a connection response is given to the upper layer LU (S).
4).

After the call setup is completed, the upper layer LU transfers data to the network layer L3 (S5), and in response thereto, the network layer L3 carries out data communication with the other party via the network NT (S6). .. When such data communication is completed, the network layer L3 becomes the upper layer LU.
Is notified of the transfer completion (S7).

As a result, the upper layer LU issues a disconnection request to the network layer L3 (S8), and accordingly the network layer L3 also issues a disconnection request to the network NT side to disconnect the network connection (call) (S9). , When the disconnection response is given from the network NT side (S1
0), the network layer L3 gives a disconnection response to the upper layer LU (S11).

As described above, in connection-oriented communication, it is necessary to set / disconnect the connection every time data is transferred.

(2) Connectionless Communication FIG. 3 shows the flow of call control in the connectionless communication mode.

In connectionless communication, the path for data transfer in the network NT is fixed, that is, data transfer is performed via the fixed path, and a call is always placed. Therefore, in the connectionless communication, unlike the connection-oriented communication, the connection request and the disconnection request for the network connection are not given from the upper layer LU to the network layer L3, and the network layer L3 sends them to the network NT side. Nor give to.

That is, the upper layer LU is the network layer L.
3 is transferred (S12), and the network layer L3 transfers (communicates) the data to the network NT side (S13).

[0011]

However, each of the above-mentioned two communication modes has merits and demerits, which are contradictory to each other.

In connection-oriented communication, since a network connection is established (call setup) / disconnection for each call, the other party is not limited and the connection can be established only when necessary. Even when using, the user fee is low.
However, when the data communication terminal attempts to transfer data with a plurality of destinations or divides transmission data into a plurality of small blocks and transfers the data, a network connection is established (call setup) each time. ) / Disconnect operation is required and rapid data transfer cannot be executed.

In connectionless communication, since a call is always placed, data transfer can be performed immediately when the data communication terminal (upper layer LU) desires data transfer. However, since it is a dedicated connection, the user usage fee is high, and since a fixed path is used, there is no versatility in path setting, and communication partners are limited. In practice, the connectionless communication mode is adopted only in the case of one-to-one communication or one-to-N communication.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a call control system capable of solving both the drawbacks of connection-oriented communication and connectionless communication.

[0015]

In order to solve such a problem, according to the present invention, in a call control method for data communication using a switching network, call setup is performed by connection-oriented call control at the start of communication, and a call is set. After the setting is completed, the connectionless call control is switched to and the call is automatically disconnected when the data communication according to the connectionless call control is not performed for a predetermined time.

[0016]

In the present invention, call setup is performed by connection-oriented call control at the start of communication. After this call setup is completed, call control is performed by switching to connectionless call control. That is, when the data communication terminal desires the data transfer, the data transfer is immediately executed without setting the call, and the call is not disconnected even when the data transfer is completed. However, if the data communication according to the connectionless call control is not performed for a predetermined time, the call is automatically disconnected.

That is, until the data communication is not executed for a long time (predetermined time) by one call setting, the number of times of quick data communication using the call is made by using the path by the call setting. Is also possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. Here, FIG. 1 is an explanatory diagram showing the flow of a basic call control according to this embodiment.

This embodiment is characterized in that connection-oriented communication and connectionless communication are selectively used according to the stage of call control. That is, the feature is that the connection-oriented communication mode is followed until the network connection is established (call setup), and the connectionless communication mode is followed thereafter.

First, before explaining the details of the embodiment, a basic call control flow applied to the embodiment will be described with reference to FIG.

When attempting communication, the upper layer LU gives a connection request to the network layer L3 (S1).
4) In response, the network layer L3 issues a connection request to the network NT side to establish a network connection (S15). When there is a connection response from the network NT side (S16), the network layer L3 gives a connection response to the upper layer LU to notify the establishment of a network connection (call setting) (S17).

As described above, the call control processing is performed according to the connection-oriented communication mode until the network connection is established (call setup).

The upper layer LU provides the network layer L3 with the data to be transferred after the network connection establishment notification is provided (S1).
8). When the network layer L3 receives the data, it outputs the data to the network NT side (S19).

As described above, the network layer L3 transfers data each time it is supplied from the upper layer LU, but when the data communication with the network NT side is stopped, the non-communication time is monitored. .. When the non-communication time reaches a predetermined time (for example, about 1 hour), a disconnection request is automatically output to the network NT side (S2
0). As a result, the network NT side disconnects the network connection (call), and the network layer L
A disconnection response is given to 3 (S21).

As described above, after the network connection is established, the connection is always established if the non-communication time does not exceed the predetermined time. Therefore, the upper layer LU only needs to give the data to the network layer L3. That is, call control according to the connectionless communication mode is performed.

When the communication is restarted after the call is disconnected, the upper layer LU performs the call control from the call setting process according to the connection-oriented type communication mode as described above.

FIG. 4 shows a communication state when an embodiment in which the present invention is applied to a wide area network system in which a plurality of LANs are connected, and of course, the basic communication shown in FIG. It has a flow. Note that FIG.
FIG. 4 (B) shows a state of communication at the time of call setting processing, and FIG.
Shows the state of communication during data transfer. Further, FIG. 5 shows a configuration of processing units of the terminal and the interworking unit.

In FIG. 4, this wide area network system includes a plurality of terminals (hereinafter, referred to as CL terminals) 11a to 11c, 1 according to a connectionless communication mode.
LAN 11, 1 having 2a-12c, 13a-13c
2, 13 and an interworking unit (I) for connecting the corresponding LAN to another network (switching network).
WU) 21, 22, and 23 and switching network (for example, public network) 3
0 and a CL communication relay device 3 having a function of relaying communication data of a CL terminal to a partner (path setting to the partner terminal)
It consists of 1.

Here, each CL terminal 11a to 11c, 12
As shown in FIG. 5, a to 12c and 13a to 13c have respective layer processing units 41 to 44 for performing respective layer processing in data communication with the corresponding interworking units 21, 22, 23. Here, the upper layer processing unit 4
4 and the layer 3 processing unit 43 perform the connectionless type processing as shown in FIG. That is, CL
Terminals 11a-11c, 12a-12c, 13a-13c
And the corresponding interworking units 21, 22,
Data communication with 23 is always executed in a connectionless communication mode.

Each interworking unit 21, 2
2 and 23 have a processing function of each layer,
CL terminals 11a to 11c, 12a to 12c, 13a to 1
U related to data communication with the switching network 30 and layer processing units 51 to 54 of U system (data system) related to data communication with 3c.
System layer processing units 61 to 64 and C system (call control system) layer processing units 71 and 72 related to data communication with the switching network 30.
Have and. The layer processing unit 61 is common to the U system and the C system.

Here, each interworking unit 2
Other than those having the upper layer processing units 54 and 64 shown in FIG. 5 as 1, 22, 23, there are also those not having the upper layer processing units 54 and 64 (not shown), but such an interworking unit In this case, the two U-system layer 3 processing units 53 and 63 are common.

In the case of this embodiment, each interworking unit 21, 22, 23 switches the connectionless type control and the connection oriented type control in the data communication with the switching network 30, as shown in FIG. To do. That is, the upper layer processing unit 64
Corresponds to the upper layer LU in FIG. 1, and the layer 3 processing unit 6
Reference numerals 3 and 72 correspond to the network layer L3 in FIG. Here, the U-system layer 3 processing unit 63 is in charge of data transfer, and the C-system layer 3 processing unit 72 is in charge of call control.

Also, each interworking unit 2
1, 22, and 23 have a timer function which is activated from the time when the data communication is interrupted, and can monitor a predetermined time. This function is executed by the C-system layer 3 processing unit 72.

The CL communication relay device 31 is actually provided in association with the switching network (public network) 30,
One or more pieces of path information corresponding to the instructed call are stored in advance, and when the transfer data is given, the path is set according to the destination information included in the data.

Next, a call setting process in the wide area network system including the above-mentioned respective parts will be described. LA
When communication data is generated in any terminal of N11 (referred to as 11a), the interworking unit 21 is triggered by the data generation given in the state where the call is disconnected, as shown in FIG. 4 (A). In addition, the call control according to the connection-oriented type communication mode causes the switching network 30 to set up a call between the interworking unit 21 and the CL communication relay device 31. Specifically, the interworking unit 21
The U system upper layer processing unit 64 requests the path setting through the C system lower layer processing units 72, 71, 61.

If the interworking unit does not have the upper layer processing units 54 and 64, the layer 3
The processing unit (where the processing units 53 and 63 are made common)
A path setting is requested through the lower layer processing units 71 and 61 of the C system. Therefore, in this case, the sequences S14 and S17 in the basic flow of FIG. 1 described above are unnecessary.

When the call is set up in this manner, the call control in the interworking unit 21 is switched to that according to the connectionless communication mode, and the interworking unit 21 transfers the data to the switching network 30 side. Specifically, the U system layer 3 processing unit 64 of the interworking unit 21 transfers data through the U system lower layer processing units 61 to 63. At this time, as shown in FIG. 4B, the CL communication relay device 31 sets a path according to the destination information included in the transfer data and transfers the data to the partner CL terminal. Also,
The interworking unit 21 monitors for a predetermined time from the end of this communication.

For example, the predetermined time is selected to be about one hour, and in many cases, one of the CL terminals 11a, 11b, 11 of the LAN 11 is set before the predetermined time elapses.
Communication involving c takes place. When call setup is performed between the interworking unit 21 and the CL communication relay device 31, the interworking unit 21
All the CL terminals 11a to 11c connected to can use the call (connection) to perform data communication.

For example, the CL terminal 11a which activated the call setting
When communication data is generated in the CL terminal 11c different from that before the elapse of a predetermined time, the interworking unit 21 transfers the data to the switching network 30 side immediately after receiving the data. Also in this case, the CL communication relay device 3
1 selects a path according to the destination information included in the data and transfers the data to the partner terminal. Further, the interworking unit 21 activates monitoring for a predetermined time from the end of this communication.

When the time during which the data communication according to the connectionless communication mode is not executed exceeds the predetermined time monitored by the interworking unit 21, the interworking unit 21 gives a disconnection request to the switching network 30 side, whereby , Interworking unit 21
The call between the CL communication relay device 31 and the CL communication relay device 31 is disconnected. Specifically, the C-system layer 3 of the interworking unit 21
The processing unit 72 performs disconnection processing through the C-system lower layer processing units 71 and 61.

When the data transfer is restarted after the disconnection, the call setup according to the connection-oriented communication is performed again.

Therefore, according to the above embodiment, once the call setup is performed, the call control according to the connectionless communication mode is executed until the call is disconnected, so that the call setup is performed every time the data communication is performed. / No disconnection is required and data transfer can be performed quickly. For example, even when the data is divided and given from the CL terminal, it is not necessary to set / disconnect the call each time, and the data can be transferred immediately.
Further, even when the same data is transmitted to a plurality of parties, if those paths are set in the CL communication relay device 31, data transfer can be immediately performed sequentially without performing call setup / disconnection each time. it can. Incidentally, only at the time of call setup, the transmitting CL terminal feels some waiting time before the start of data transfer.

Even in this case, if the data communication is not executed for a long period of time, the call is disconnected, so that the usage fee can be reduced as compared with the conventional case even if the public network is used. Incidentally, connectionless communication has been widely adopted for communication using a dedicated line, and in the past, the usage fee was considerably effective.

Further, by storing the path information relating to a plurality of calls in the CL communication relay device 31 so that the path information can be selected in the call setting, the path can be given versatility. Similarly, for the same call, C
By setting the L communication relay device 31 in advance, the path can be made versatile.

In the above embodiment, a plurality of LAs are used.
Although the present invention is applied to a wide area network system in which N are connected, the present invention can be applied to network systems of other configurations. In short, the present invention can be applied to a network system in which data communication is repeatedly generated without opening a long time for a call placed once.

In the above embodiment, the path information is stored in the CL communication relay apparatus 31 in advance. However, the path information is given at the time of call setting, and the CL relay apparatus 31 is provided.
You may make it store it in.

[0047]

As described above, according to the present invention, in the call control method in the data communication using the switching network, the call setup is performed by the connection-oriented call control at the start of the communication, and the connectionless is performed after the call setup is completed. In addition to switching to type call control, the call is automatically disconnected when data communication according to the connectionless type call control is not performed for a predetermined time, so that data transfer can be executed quickly and call setting has general versatility. It is possible to realize a call control method that can shorten the use time of the switching network (call).

[Brief description of drawings]

FIG. 1 is a sequence diagram showing a basic flow of call control according to an embodiment.

FIG. 2 is a sequence diagram showing a call control flow in a connection-oriented communication mode.

FIG. 3 is a sequence diagram showing a flow of call control in a connectionless communication mode.

FIG. 4 is a block diagram showing the manner of communication during call setup and data transfer according to the embodiment.

FIG. 5 is a block diagram showing a configuration of processing units of a CL terminal and an interworking unit according to the embodiment.

[Explanation of symbols]

11, 12, 13 ... LAN, 11a to 11c, 12a to
12c, 13a to 13c ... CL terminal (having upper layer processing function), 21, 22, 23 ... Interworking unit (IWU: having network layer processing function), 30 ... Switching network (public network), 31 ... CL communication relay device.

Claims (1)

[Claims] 1. In a call control method for data communication using a switching network, call setup is performed by connection-oriented call control at the start of communication, and after completion of call setup, connectionless call control is performed and connectionless call control is performed. A call control method characterized by automatically disconnecting a call when data communication according to control is not performed for a predetermined time.