JPH04126421A - Call setup control syste in isdn exchange - Google Patents

Abstract

PURPOSE:To prevent an event that call setup is not implemented regardless of the presence of an available channel by informing the operating state of the channels to an ISDN subscriber terminal equipment being a setup request party and allowing the said ISDN subscriber terminal equipment to recognize an idle channel and to select an operating channel. CONSTITUTION:A packet handler 2 detects the operating state of channels assigned to an ISDN subscriber subject to call setup (connection) in other packet mode calls at the time of arriving a packet mode call, and sends the result of detection to a line switching exchange 1 as channel information, the exchange 1 detects calls (line switching exchange mode calls) other than the packet mode call, revises the said channel information accordingly and sends the said revised channel information to an ISDN subscriber terminal equipment 8. The said ISDN subscriber terminal equipment 8 recognizes an idle channel from the channel information and selects a channel to be used among the said idle channels and returns the result of selection to the exchange 1 and the packet handler 2.

Description

[Detailed Description of the Invention] Overview Regarding a call setup control method in an ISDN switch, the present invention aims to improve the efficiency of call setup processing, and includes a circuit switch that performs circuit switching processing and a packet handler connected to the circuit switch. Processing for packet mode calls is carried out by the packet handler, which detects the usage status of the channel by the packet mode call for the subscriber to whom the call setup request is made, when a call setup request signal arrives. A first detecting means is provided in the packet handler, and a second detecting means is provided in the packet handler for detecting the usage status of a channel by a call other than a packet mode call for the call setting request destination subscriber when a call setting request signal is received. The packet handler includes the channel usage status determined by the first detection means in a call setup request signal as channel information and sends it to the circuit exchange; updating the channel information in accordance with the channel information, including the updated channel information in a call setup request signal and sending it to the subscriber terminal to which the call setup request is made, the subscriber terminal recognizing an available channel from the channel information; Configure to select which channels to use.

INDUSTRIAL APPLICATION FIELD The present invention relates to a call setup control method in an ISDN exchange.

An integrated digital network that provides multiple different communication services such as telephone, data, facsimile, and image through a single communication network composed of digital exchanges and digital transmission lines is called an integrated digital communication network (ISDN:
Integrated 5 services D+git
alNetwork).

ISDN is a communication network that is expected to develop in the future, having the following characteristics when compared with networks that provide individual services such as telephone networks, data networks, and facsimile networks. That is, (1) New services can be provided economically by reducing network costs through sharing and integrating communication network equipment.

(2) Management costs can be reduced by centralizing communication network operation and management.

(3) All kinds of information signals such as telephone calls, data, images, etc. can be transmitted using the same physical component called a pulse train, and there is flexibility for diversifying services.

(4) It has features such as accommodating a variety of terminal types and realizing complex communication services that can provide multiple communication services simultaneously, improving user convenience.

In order to realize the various services mentioned above, the ISDN switch used in ISDN (2) needs to process all kinds of mode calls at high speed. For this purpose, there is a demand for highly efficient call setup processing in a function-distributed ISDN switch in which each packet handler handles the processing separately.

BACKGROUND ART FIG. 8 shows a schematic configuration of an ISDN exchange. This ISDN switch accommodates a plurality of ISDN subscribers 11, and is a circuit switch 1 that realizes circuit switching mode call switching processing.
2 and the line exchange! This is a function-distributed ISDN switch that is constructed of a packet handler 13 that is subordinate to and connected to 1112 and realizes packet mode call switching processing. The circuit switching equipment 12 performs processing to realize circuit switching mode call connection control functions, packet handler connection functions, etc. based on the CCI TT Recommendation Q and 931 protocols,
The packet handler 13 performs processing for realizing packet exchange functions, packet data transfer functions, etc. between ISDN subscribers.

A conventional call setting procedure in the ISDN exchange will be explained with reference to FIG. In addition, the above ISDN subscriber 1
1 interface has two B channels (Bl, B2)
The description will be made assuming that a packet mode call is received from another ISDN exchange to an ISDN subscriber 11 accommodated in the ISDN exchange.

A call setup request signal (SET U) is sent to the packet handler 13.
When the packet handler 13 receives the IS signal), the packet handler 13
Determination of whether there is a usable channel among the channels assigned to the DN subscriber 11, and the ISDN
A determination is made as to whether the subscriber 11 has subscribed to a packet communication service, and if it is determined that the call can be received, a call setup request signal is sent to the circuit exchange 12 (901). The line exchange 12 determines whether or not there is a usable channel among the channels assigned to the ISDN subscriber to receive the call, and if there is a usable channel, a call setup request signal is sent to the subscriber terminal 12. (902). The subscriber terminal 11 uses the channel (
B1. B2. Select one of D) (for example, B
2), information indicating the selected channel is added to an incoming call confirmation signal (CONNECT signal) and sent to the line exchange 12 (903). The circuit exchange 12 determines whether the channel selected by the subscriber terminal 11 is being used by a circuit-switched mode call, and if not, sends an acknowledgment signal (CONNECT ACK signal) to the subscriber terminal 11. 904), the subscriber terminal 11
An incoming confirmation signal to which information indicating the selected channel is added is sent to the packet handler 13 (905). The packet handler 13 determines whether the channel selected by the subscriber terminal 11 is usable or not, and if it is usable, it performs call setup using the channel, and if it is not usable, it performs call setup using the channel. Hang up a packet mode call.

Problems to be Solved by the Invention As mentioned above, according to the prior art, a subscriber terminal arbitrarily selects one of the channels assigned to it and establishes a call using the selected channel. The circuit switch 12 and packet handler 11 are notified to do so, and the circuit switch and packet handler each determine whether the selected channel can be used by the packet mode call, and if it is determined that the selected channel cannot be used, disconnect the call. controlled to do so. Therefore, for example, if the subscriber terminal selects the 82 channel when the B1 and D channels are available and the 82 channel is unavailable, the 81 and D
The call will be disconnected even though the channel is available, which is very inefficient.

The present invention has been made in view of the above points, and an object of the present invention is to improve the efficiency of call setting processing for packet mode calls.

A promising means of solving problems FIG. 1 is a diagram for explaining the present invention in detail.

A functionally distributed ISDN switch is equipped with a circuit switch 1 that performs circuit switching processing, and a packet handler 2 connected to the circuit switch 1, and the packet handler 2 performs processing for packet mode calls. A first detecting means 4 is provided in the packet handler 2 for detecting the usage status of a channel by a packet mode call for the subscriber to whom the call setting request is made when the call setting request signal 3 is received, and when the call setting request signal 5 is received, A second detecting means 6 for detecting the usage status of a channel by a call other than a packet mode call for the subscriber to whom the call setting request is made is provided in the circuit exchange 1.
Provided for. Then, the packet handler 2 includes the channel usage status by the first detection means 4 as channel information in the call setup request signal 5 and sends it to the line exchange 1. The channel information is updated according to the usage status, and the updated channel information is added to the call setup request signal 7 and sent to the call setup request destination subscriber terminal 8, and the subscriber terminal 8 selects an available channel from the channel information. configured to recognize and select which channels to use.

According to the present invention, when a packet mode call is received, the packet handler 2 detects the usage status of the channel assigned to the ISDN subscriber to be set up (connected) by another packet mode call, and The circuit exchange 1 detects the usage status by calls other than packet mode calls (circuit switched mode calls), updates the channel information accordingly, and transmits the updated channel information to the ISDN. The information is sent to the subscriber terminal 8. Then, the subscriber terminal 8 recognizes free channels from this channel information, selects a channel to be used from among the free channels, and sends it back to the line exchange 1 and the packet handler 2. As a result, the channel selected by the subscriber terminal 8 can be used at all times, so that the situation where the call is disconnected even when there is an empty channel that can be used as in the conventional technology can be avoided. Therefore, high efficiency can be achieved.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a diagram showing an ISDN switching system to which the present invention is applied. 20a and 20b are ISDN exchanges,
These ISDN exchanges 20a.

20b is a line exchange that performs line exchange processing! 21a, 2
1b and packet handlers 22a and 22b connected to the line exchanges 21a and 21b, and the packet handlers 22a and 22b perform processing for packet mode calls.

Each line exchange 21a, 21b has a control unit (CC) 23a,
23b.

It is configured with main memories (MM) 24a, 24b and network parts (NW) 25a, 25b, and the network parts 25a, 25b include subscriber lines 28a, 28.
ISDN subscriber terminals 29a and 29b are connected via b. The packet handlers 22a and 22b are control units (
CC) 26a, 26b and main memory (MM) 27
a, 27b.

Network section 25a of ISDN exchange 20a and ISD
The network section 25b of the N exchange 20b is the communication line 3.
0, and is connected to the control unit 23a of the line exchange 21a.
The control i2:3b of the line exchange 21b, the control unit 26a of the packet handler 22a, and the control 11 unit 26b of the packet handler 22b are connected by control lines 31 and 32, respectively.

In this embodiment, it is assumed that the ISDN subscriber's interface is a basic rate interface consisting of two B channels and one D channel.
The following description assumes that the DN subscriber terminal 29b is a packet originating terminal and the ISDN subscriber terminal 29a is a packet receiving terminal.

A call setup request signal (SE
T UP double signal is circuit switched! It is sent to the control line 32 via the network unit 25b1 of the packet handler 21b, the control unit 23b1 of the packet handler 22b, and the control unit 26b of the packet handler 22b. The ISDN exchange 20ajl that receives the call setup request signal performs the processes shown in FIGS. 3 to 5.

First, refer to FIG. 4. When the call setup request signal arrives at the packet handler 22a via the control line 32, the packet handler 22a sends the subscriber number (address) of the ISDN subscriber (hereinafter sometimes referred to as called subscriber) 29a to which the call setup is requested. information), refer to the subscriber information table in which subscription service information (information indicating the status of subscription to a service), line information, etc. is set and stored for each subscriber as shown in FIG. , the channel usage status of the called subscriber 29a is detected from the line used, communication volume (throughput), etc. at the time of the call setup request (step 4).
01).

Then, based on the detected channel usage status, it is determined whether there is a channel that can be used for communication by the called subscriber 29a (step 402).

If there is no usable channel, the packet mode call is disconnected as the call cannot be received (step 403).
. If there is a usable channel, as shown in FIG.
It includes channel information for notifying whether each channel assigned to a can be used and sends it to the line exchange 21a (step 405). The channel information is set according to the channel usage status of the called subscriber, and in this case, the usage status of the channel by another packet mode call is set.

Referring now to FIG. The line exchange 21a that has received the call setup request signal to which the channel information has been added determines whether or not the D channel is the only channel that the packet handler 22a has made usable.
1) If only the B channel or both the B channel and the D channel are used, detect the channel usage status of the channels enabled by the packet handler 22a by the circuit switched mode call (Step 502), all of them are in use. If so, the packet handler 22a is notified that the incoming call is rejected (step 503).

If a part of the channel is being used by a circuit-switched mode call, the channel information added to the call setup request signal is updated according to the usage status (step 504), and the updated channel information is added to the call setup request signal. ISD with information added
It is sent to N subscriber terminals 29a (step 505). If only the D channel is available in step 501, and if all channels are empty in step 502, the channel information that will not be updated is added to the call setup request signal as is and sent to the ISDN subscriber terminal 29a (step 505).

Referring now to FIG. When the line switch 21a receives a call setup request signal including channel information from the packet handler 22a (301), and the ISDN subscriber terminal 29a receives a call setup request signal including updated channel information from the line switch 21a (302), The ISDN subscriber terminal 29a recognizes an empty channel from the channel information, selects a channel to be used (for example, selects the Bl channel), adds this to an incoming call confirmation signal (CONNECT signal), and sends it back to the line exchange 21a ( 303). The line exchange 21a sends a confirmation signal (CONNECT ACK signal) to the ISDN subscriber terminal 29a (304),
The packet handler 22a sends an incoming confirmation signal indicating that the Bl channel has been selected (305). The packet handler 22a uses the B1 channel to set up a call, and thereafter communication between the SDN subscriber terminal 29a and the ISDN subscriber terminal 29b becomes possible.

According to this embodiment, the ISDN subscriber terminal 29a, which is the destination of the call setup request, can recognize available channels and select and determine the channel to be used from among the available channels. This eliminates the problem of not performing call setup even though there are usable channels, unlike in the prior art.

In the above embodiment, an ISDN subscriber to whom a basic rate interface is applied is explained as an example, but the present invention is not limited to this, and for example, an ISDN subscriber to whom a - next group interface is applied is explained. Needless to say, the present invention can be applied to any case.

Effects of the Invention As described in detail above, the present invention provides an IS that is the destination of a call setup request.
The channel usage status is notified to the DN subscriber terminal, and the corresponding IS
Since the DN subscriber terminal recognizes an empty channel from the usage status of the channel and selects the channel to be used, there is no need to set up a call even though there is an available channel. This has the effect of making it possible to perform highly efficient call setup for mode calls.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention. Fig. 2 is a block diagram of an embodiment of the present invention. Fig. 3 is communication content for call setup between a packet handler, a circuit switch, and a subscriber terminal in an embodiment of the present invention. FIG. 4 is a flowchart showing part of the processing by the packet handler in the embodiment of the present invention, FIG. 5 is a flowchart showing part of the processing by the circuit switch in the embodiment of the invention, jf! 6 is a diagram for explaining a call setup request signal in an embodiment of the present invention, FIG. 7 is a diagram illustrating a subscriber information table in an embodiment of the present invention, FIG. 8 is a diagram illustrating a schematic configuration of an ISDN exchange, FIG. 9 is a diagram showing the contents of communication for call setup between a packet handler, a circuit switch, and a subscriber terminal in the prior art. 1... Line exchange, 2... Packet handler, 3.5.7... Call setup request signal, 4... First detection means, 6... Second detection means, 8... Joining user terminal.

Claims (1)

[Scope of Claims] A circuit switch (1) that performs circuit switching processing, and a packet handler (2) connected to the circuit switch (1), wherein processing for packet mode calls is performed by the packet handler (2). In a function-distributed ISDN exchange implemented by ) is provided in the packet handler (2), and when the call setup request signal (5) is received, a second detection means ( 6) is provided in the line exchange (1), and the packet handler (2) includes the channel usage status by the first detection means (4) as channel information in the call setup request signal (5) and sends it to the line exchange (1). 1), the line exchange (1) updates the channel information according to the channel usage status by the second detection means (6), and includes the updated channel information in the call setup request signal (7). The ISD is characterized in that the subscriber terminal (8) recognizes available channels from the channel information and selects the channel to be used.
Call setup control method in N exchange.