JPH06350730A - Isdn subscriber system - Google Patents

Abstract

PURPOSE:To provide an ISDN subscriber system which can effectively execute communication between terminals housed in an ISDN exchange by using a B channel. CONSTITUTION:At an ISDN exchange 01, the throughput variables of channel buses B1 and B2 are monitored, the channel with no throughput variable is discriminated by this monitor, and an interruption message is sent to an NT 02. The NT 02, which receives this interruption message, interrupts the designated channel, prepares an interruption confirmation message and sends it to the ISDN exchange as a response message. The ISDN exchange 01, which receives this interruption confirmation message, turns to the waiting state of a call setting request and when the call setting request is received, a channel assignment instruction message corresponding to the request is sent to the NT 02. The NT 02, which receives this message, assignes the channel in the interruption state to the requesting terminal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISDN (Integrated Services Digital Network) subscriber system, and particularly to ISD.
The present invention relates to communication management technology between an N exchange and a terminal accommodated in the ISDN exchange.

[0002]

2. Description of the Related Art In a conventional ISDN subscriber system,
The B channel used for communication between the ISDN exchange and the terminal was determined at the time of call setup, and the B channel used could not be allocated for communication with other terminals until the call disconnection was completed. .

That is, since the B channel used for communication is determined at the time of call setup and is held until the call disconnection is completed, all B channels are used for communication between the ISDN exchange and the terminals accommodated therein. When used, there was a problem that communication with the accommodated terminals was refused.

[0004]

As described above, in the conventional ISDN subscriber system, when all the B channels are used for communication between the ISDN exchange and the terminals accommodated therein, There was a problem that communication with the accommodated terminals was refused.

The present invention has been made to solve the above-mentioned problems, and identifies an interruptable B channel, interrupts it, and causes the interrupted B channel to be used by another terminal accommodated in an ISDN exchange. And I
An object of the present invention is to provide an ISDN subscriber system capable of effectively executing communication between terminals accommodated in an SDN exchange by using a B channel.

[0006]

In order to achieve the above object, the present invention provides an ISDN exchange for selectively connecting various communication lines and a subscriber line, and connecting the ISDN exchange with the subscriber transmission line. An ISDN subscriber system having a network terminating device serving as a terminating device of this subscriber line transmission line and a plurality of terminals connected through a plurality of digital transmission channel buses and having a number larger than the number of buses. In the above, the ISDN exchange has a function of monitoring throughput amounts of a plurality of channel buses, a function of sending an interruption message to a network terminating device when a channel whose throughput amount is exhausted by this monitoring is discriminated, and After receiving the response message, the call setup request waits,
When a call setup request is received, the network terminating device has a function of sending a channel assignment instruction message to the network terminating device in response to the request, and when the network terminating device receives the interruption message sent from the ISDN exchange, it transmits the designated channel. Along with the suspension, the function of creating a suspension confirmation message and sending it as a response message to the ISDN exchange, and when the channel assignment instruction message sent from the ISDN exchange is received, the requesting terminal is in a suspended state. It is characterized by having a function of allocating channels.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the structure of an ISDN subscriber system to which the present invention is applied, where 01 is an ISDN exchange for selectively connecting various communication lines and subscriber lines, and 02.
Is an NT (network terminating device)
For example, PBX (extension switch), terminal control device, etc.), 10, 20, and 30 are terminals.

The ISDN exchange 01 and NT02 are connected by a digital subscriber line. NT02 and each terminal 10,
20 and 30 are connected by a B channel bus composed of two systems, B1 and B2, but are also connected by a D channel bus (not shown).

FIG. 2 shows a control flow of the ISDN exchange 01 according to the present invention, and FIG. 3 shows a control flow of the NT02 according to the present invention. Note that, here, as the initial state, it is assumed that both channels B1 and B2 are in use.

First, the ISDN exchange 01 is constantly connected to B1,
The throughput amount of the B2 channel is monitored (step a), and it is determined whether or not the throughput amount of each channel is exhausted (step b). Here, when there is a channel with no throughput, an interruption message is sent to NT02 (step c).

The format of this interruption message is, for example, as shown in FIG.
It is composed of a call number M2, a message type M3, and a call identification M4, and is coded as shown in FIG. 4B, for example.

On the other hand, when the NT02 side receives the interruption message (step h), it creates an interruption confirmation message and sends it as a response message to the ISDN exchange 01. The format of this interruption confirmation message is, for example, as shown in FIG. 5 (a), composed of a protocol identifier M5, a call number M6, a message type M7, and information content (display) M8. For example, as shown in FIG. 5 (b). Coded in.

FIG. 6 shows a sequence example of an interruption message and a response message between the ISDN exchange and NT.

When the ISDN exchange 01 receives this interruption confirmation message (Y in step d), it enters a standby state for a call setup request (step e). When the call setting request is received (Y in step f), the request channel assignment instruction message is sent to NT02 (step g).

Upon receiving this channel allocation instruction message (Y in step k), the NT02 allocates the suspended channel to the requesting terminal (step l).

The operation of the above arrangement will be described more specifically.

Now, the terminals 10 and 20 are respectively B1
It is assumed that the channel and B2 channel buses are used and communication is possible with the ISDN exchange 01 via NT02. At this time, the ISDN switch 01 uses the B1 channel,
Monitor the throughput amount of the B2 channel.

When the ISDN exchange 01 determines that there is no B2 channel throughput, it sends a suspension message to NT02 to suspend the B2 channel used for communication with the terminal 20. Upon receiving this interruption message, the NT02 interrupts the communication on the B2 channel used between the ISDN exchange 01 and the terminal 20, and sends an interruption confirmation message to the ISDN exchange 01 as a response to the interruption message.

When a call setup request is transmitted from the terminal 30 to the ISDN exchange 01 in such a situation, the ISDN exchange 01 allocates the B channel B2 interrupted with the terminal 20 to the terminal 30, and It communicates with the ISDN exchange 01.

Therefore, the ISDN subscriber system having the above configuration monitors the throughput amount of the terminal accommodating the ISDN exchange and interrupts the communication using the B channel with the terminal having no throughput amount.
The interrupted B channel can be used for communication between the ISDN exchange and the accommodated terminal, and effective use of the B channel can be realized.

It is needless to say that the present invention is not limited to the above-described embodiments, and that various modifications may be made without departing from the scope of the present invention.

[0023]

As described above, according to the present invention, it is possible to identify and suspend an interruptable B channel, and use the interrupted B channel in another terminal accommodated in the ISDN exchange. This makes it possible to provide an ISDN subscriber system capable of effectively executing communication between terminals accommodated in an ISDN exchange using the B channel.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an ISDN subscriber system to which the present invention is applied.

FIG. 2 is a flowchart showing a control flow of an ISDN exchange as an embodiment of the ISDN subscriber system according to the present invention.

FIG. 3 is a flowchart showing an NT control flow as an embodiment of the ISDN subscriber system according to the present invention.

FIG. 4 is a diagram showing a format of an interruption message and its coding example in the embodiment.

FIG. 5 is a diagram showing a format of an interruption confirmation message and its coding example according to the embodiment.

FIG. 6 is a diagram showing a sequence example of an interruption message and a response message between the ISDN exchange and the NT of the embodiment.

[Explanation of symbols]

 01 ISDN Switch 02 NT (Network Terminator) 03 Digital Subscriber Line 10, 20, 30 Terminal B1, B2 B Channel Bus

Claims (1)

[Claims] 1. An ISDN exchange for selectively connecting various communication lines and a subscriber line, and a network terminal which is connected to the ISDN exchange through a subscriber transmission line and serves as a terminating device for the subscriber line transmission line. In an ISDN subscriber system having a device and a plurality of terminals, which are connected via a plurality of digital transmission type channel buses and have a number larger than the number of buses, the ISDN exchange is configured so that the throughput amount of the plurality of channel buses is increased. And a function for sending an interruption message to the network terminating device when a channel whose throughput has been exhausted is discriminated by this monitoring, and a standby state for a call setting request upon receiving a response message from this network terminating device. A function of sending a channel allocation instruction message according to the request to the network terminating device when the call setting request is received, When the terminating device receives an interruption message sent from the ISDN exchange, it terminates the designated channel, creates a confirmation message for interruption, and sends it as a response message to the ISDN exchange. And a function of allocating a channel in a suspended state to a requesting terminal when receiving the channel allocation instruction message.