JPH0818557A - Line exchange connection method for network system - Google Patents

Abstract

PURPOSE:To attain a connection request to be connected to a terminal equipment whose accommodation is replaced by deciding an exchange station being an accommodation replacement destination in advance on the occurrence of a fault in an exchange station, storing a table with the destination station to each exchange station and selecting an exchange station in a predetermined sequence based on destination subscriber address information in the case of making a call. CONSTITUTION:An exchange station being an accommodation replacement destination is decided sequentially as to information of an accommodation replacement destination (station number) with respect to destination subscriber addresses and registered in a station number dependent object station number table (retrieval table) in the order of priority. For example, the 1st priority accommodation replacement destination of subscriber terminals accommodated in an exchange station 2 is decided to be an exchange station 3. For example, when a subscriber terminal equipment 10 makes a call to a subscriber terminal equipment 20, an exchange station 1 sends a connection request to the exchange station 2 based on destination subscriber address information of the subscriber terminal equipment 20 at first. However, the exchange station 2 cannot be connected due to a fault. Then the retrieval table stored in itself is referenced and a connection request is sent to the an accommodation replacement destination 3 of the 1st priority and then the connection is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit switching connection method for a network system, and more particularly to an address conversion method for making a call in communication.

[0002]

2. Description of the Related Art In a network system composed of a plurality of exchanges connected to each other by a line, if a failure occurs in the exchanges or the like, in the worst case, communication of the entire network becomes impossible. Therefore, it is also practiced to secure reliability by using a packet switch at the switching center. That is, in a network system configured to use a packet switch as a switch, communication routes can be switched by bypassing a faulty switch to improve network reliability and ensure communication.

However, even in this case, it is naturally impossible to communicate with the subscriber terminal accommodated in the fault exchange station. This will be described with reference to FIG. 5 as an example. In FIG. 5, reference numerals 1 to 3 are switching stations, and the switching stations 1 to 3 are connected by communication lines L1 to L3, respectively, to secure communication routes for mutual communication. 10-12, 20-
22 and 30 to 32 are subscriber terminals. Switching center 1 accommodates subscriber terminals 10-12, switching center 2 accommodates subscriber terminals 20-22, and switching center 3 regulates subscriber terminals 30-.
It houses 32. L10-L12, L20-L2
2, L30 to L32 are subscriber lines that connect the subscriber terminal and the exchange.

Referring now to FIG. 5, of the exchanges 1 to 3,
It is assumed that the exchange 2 becomes the fault exchange. However, in such a network, even if a failure occurs in the switching center 2, since the healthy switching center 1 and the switching center 3 have a communication line L3 connecting them, they are accommodated in the respective switching centers 1 and 3. The subscriber terminals 10 to 12 and 30 to 32 can be exchange-connected to each other and communication is possible.

However, since the fault exchange station 2 cannot exchange due to a fault in the exchange station itself, it is impossible to exchange connection with the subscriber terminals 20 to 22 accommodated in the fault exchange station 2. It is impossible to communicate with any subscriber terminal accommodated in the fault exchange station 2.

Therefore, in such a case, the fault exchange 2
As an alternative to the above, a countermeasure may be taken such that another accommodating exchange station, for example, the exchange station 3, accommodates and changes the accommodation subscriber terminals 20, 21, 22 of the faulty exchange station 2. In this case, the accommodating subscriber terminals 10 of the healthy exchanging station 3 and the exchanging station 1 are called from the accommodating subscriber terminals 20, 21, 22 of the fault exchanging exchanging station 2 which have been accommodated by the accommodating exchanging station 3. ~ 12,
Although communication to 30 to 32 is possible, subscriber terminals 10 to 12 and 30 to 32 of these healthy switching center 3 and switching center 1 are available.
It was not possible to call the subscriber terminals 20, 21 and 22 by calling.

For example, it is possible to make a call from the subscriber terminal 20 to a subscriber terminal accommodated in a healthy exchange station other than the fault exchange station 2, for example, the subscriber terminal 10 for communication, to receive the call, and connect. However, on the contrary, it is not possible to make a call from the subscriber terminal 10 to make a call to the subscriber terminal 20 whose accommodation exchange station has been changed, and to make a connection.

This is for the following reason. This will be described with reference to the operation transition diagram of FIG. Now, it is assumed that the subscriber terminal 10 issues a connection request for communication with the subscriber terminal 20. This is performed by dialing the subscriber address ADR20 of the subscriber terminal 20 from the subscriber terminal 10 (S1).

Since this connection request is given to the exchange as a connection request signal including dial information of the called party (destination subscriber address ADR20), the exchange 1 accommodating the subscriber terminal 10 makes this connection. From the destination subscriber address ADR20 included in the request signal, the subscriber terminal 2
It is known that the exchange is the exchange 2 by searching the subscriber address-exchange exchange correspondence information table held by itself to find out where the exchange containing 0. Then, the destination subscriber address AD is sent to the exchange 2 which is found by the search.
A connection request signal including R20 is transmitted (S2).

Upon receiving the connection request signal, the switching center 2 searches for the subscriber terminal 20 from the destination subscriber address ADR20, and connects to the subscriber terminal 20 via the subscriber line to which the terminal is connected. Send request (incoming signal) (S
3). Then, when the subscriber terminal 20 responds, the response procedure is executed (S4 to S6), and the connection is completed.

On the other hand, when the accommodating switching center of the subscriber terminal 20 is changed from the switching center 2 to the switching center 3, consider that the subscriber terminal 20 is connected for communication. And it becomes like this. This will be described with reference to the operation transition diagram of FIG.

It is now assumed that the subscriber terminal 10 issues a connection request for communication with the subscriber terminal 20. This is the subscriber address AD from the subscriber terminal 10 to the subscriber terminal 20.
This is done by dialing R20 (S11).

Since this connection request is given to the exchange as a connection request signal including dial information (destination subscriber address ADR20), the exchange 1 accommodating the subscriber terminal 10 is included in this connection request signal. From the destination subscriber address ADR20, the table is searched to find out which exchange station accommodates the subscriber terminal 20, and as a result, the exchange station 2 is known. Then, the destination subscriber address A is sent to the exchange 2 which is found by the search.
A connection request signal including DR20 is transmitted (S12).

At this time, since the subscriber terminal 20 is replaced and the subscriber terminal 20 is not accommodated in the exchange 2, the exchange 2 can search for the subscriber terminal 20. Then, the exchange 2 returns to the exchange 1 that the connection is not possible and the connection cannot be established (S13). When the exchange 2 is in trouble, the exchange 2 does not accept any connection request signal for itself (S12a). Therefore, the switching center 2 does not operate at all, and switching connection cannot be performed.

As described above, in the originating exchange station 1, the destination subscriber address ADR2 included in the connection request signal is sent.
From 0, the exchange to be transmitted is searched, but since the destination subscriber terminal 20 has changed the accommodating exchange, it is in a state not accommodated by the exchange to which the connection is requested. Even if the exchange 2 is still alive, this is not the case here, and therefore the connection cannot be established.

Here, it is possible to retrieve the exchange 2 which accommodates the destination subscriber terminal 20 from the destination subscriber address ADR 20. The subscriber address system normally indicates the accommodating exchange and the exchange number. This is because it is composed of the accommodated line number (terminal line number), which allows the originating exchange to look at the exchange number in the destination subscriber's address, and to which exchange the destination subscriber's terminal is accommodated. This is because it is a mechanism to understand.

By the way, in order to solve the matters described so far, when the accommodation exchange station for a certain subscriber terminal is changed, the information of the changed accommodation exchange station of the subscriber terminal is transferred to all subscribers in the network. It suffices to inform the exchanges so that each exchange can know the current accommodation exchange. However, in this case, each switching center needs to be configured so as to be able to store and hold the subscriber addresses of all the subscriber terminals that are subscribing to the network, and the information stored in one switching center is huge. However, it is not practical.

As another solution, it is conceivable that the accommodating exchange will change the subscriber address of the changed subscriber terminal. In this case, when connecting to the changed subscriber terminal. , All subscriber terminals in the network must change the destination subscriber address,
This is not practical.

That is, in this case, since the subscriber address is new, unless the other subscribers are made aware of this new subscriber address, it cannot be designated as the destination, so after all. , The system becomes difficult to use.

[0020]

When a failure occurs in a switching center or the like in the network system, it becomes impossible to communicate with the subscriber terminal accommodated in the switching center in which the failure has occurred. Therefore, the subscriber terminal accommodated in the faulty exchange is replaced with another healthy exchange to enable communication, but in this case, the subscriber terminal originally accommodated in the healthy exchange is On the other hand, it is possible to call and connect from the subscriber terminal whose accommodation has been changed, and communication between the two becomes possible. But the opposite is not possible.

This is because the subscriber line to which the subscriber terminal is connected in the exchange is selected by the destination address given to the subscriber line. That is, the subscriber address system is usually composed of a station number indicating the accommodation exchange station and its accommodation line number (terminal line number). Among the destination addresses, the accommodation exchange station is specified by the station number and Specify the subscriber line with the accommodation line number to receive the call.

Therefore, when the accommodating exchange is changed for convenience, the subscriber address serving as the destination address for specifying the subscriber line to which the subscriber terminal is connected is also changed to the one compatible with the accommodating exchange. Since the subscriber terminal whose accommodation exchange station has been changed cannot search based on the subscriber address, it is possible to make a call but not to receive a call. Then, when the accommodation exchange station is changed for convenience, a system that can hold the information of the latest accommodation exchange station (station number) for each subscriber terminal in each exchange station so that the exchange station of the accommodation exchange destination can be known However, the amount of information stored in each exchange is enormous and it is not realistic for such a system.

It is also conceivable to newly add a subscriber address in accordance with the accommodated exchange, but in this case, it is necessary not to duplicate the subscriber address of another subscriber terminal, Since the subscriber address is changed, the station number and accommodation line number are naturally changed.

When the station number and accommodating line number that have been familiar to us from old times change, it takes time to disseminate the new station number and accommodating line number, which causes confusion only temporarily. It is too unreasonable and impractical as a sacrifice to pay to change the detention center.

As described above, in the conventional system, when the accommodation switching station of the subscriber terminal of the faulty switching station in which the fault has occurred is changed,
Since other exchanges do not have information on accommodation changes, there is a problem that incoming connections cannot be made to subscriber terminals. Also, for subscriber terminals whose accommodation exchanges have been changed, their addresses must be changed to change each exchange. It is impractical to develop a technology that enables incoming connection to the subscriber terminal with a changed accommodating exchange even without changing the subscriber address, because the method of registering with the subscriber is unrealistic. Has been done.

Therefore, the object of the present invention is to
An object of the present invention is to provide an address conversion method that enables the accommodated exchange to connect to the changed subscriber terminal without changing the subscriber address.

[0027]

In order to achieve the above object, the present invention is configured as follows. That is, it is a network system composed of a plurality of exchanges connected by communication channels and capable of mutual communication and transmission, and subscriber terminals accommodated in each of these exchanges. The subscriber terminal accommodated in the faulty exchange is accommodated in another exchange to enable communication, and the destination subscriber address of the destination subscriber terminal obtained from the calling subscriber terminal is used to accommodate and exchange. Specify a station, issue a connection request,
In accordance with this request, in the network system that selects the corresponding subscriber terminal at the specified exchange station to receive the call and connect the lines to enable communication, the exchange station of the accommodation replacement destination in advance when the failure of the exchange station occurs At the same time, each exchange shall hold list information of the planned accommodation exchanges including the specified exchange destination exchange for each exchange identified by the destination subscriber address, and According to this list, from the information of the destination subscriber address obtained from the subscriber terminal at the time of calling, the exchange stations are selected in the scheduled order and the connection request including the destination subscriber address information is issued to the selected exchange station. Characterize.

Further, a plurality of accommodating circuit numbers are made to correspond to accommodating circuit numbers in the destination subscriber address information in advance as a connection candidate at the exchange, and when the incoming call request is received, the destination subscriber address information is received. It is characterized in that the subscriber terminal of the accommodation line number selected in a predetermined order from the connection candidates corresponding to the accommodation line number in the middle is received and the line is connected.

[0029]

According to the present invention, there is provided a network system comprising a plurality of exchanges which are connected by a communication path and can communicate with each other, and subscriber terminals accommodated in these exchanges.
When a failure occurs in a certain switching center, it is intended for a system in which a subscriber terminal accommodated in this failed switching center is transferred to another switching center so that communication is possible. The destination subscriber address, which consists of the exchange subscriber's terminal accommodating exchange number and the accommodation line number of the destination subscriber's terminal as the connection destination information obtained from the other party's terminal, is used as the destination subscriber's terminal with the station number information. The accommodating exchange station is specified and a connection request is issued, and in accordance with this request, the corresponding exchange terminal is selected and received, and the line connection is made to enable communication.

Further, in the present invention, it is planned that the accommodation exchange destination exchange stations in the event of a failure of the exchange offices are defined in advance, and that each exchange office includes the accommodation accommodation destination exchange offices defined by the exchange station number. The list information of the destination exchanges is held, the exchanges are selected in the scheduled order from the information of the destination subscriber address obtained from the subscriber terminal when the subscriber terminal makes a call, and the selected exchanges are selected. Issue a connection request to the station containing the destination subscriber address information.

In the present invention, since the accommodation exchange office at the time of occurrence of a failure is predetermined in each exchange office, the candidate of the exchange office to which the connection request should be issued from the information of the destination subscriber address is scheduled. According to the list of accommodation exchanges, select in the order scheduled. Then, by issuing a connection request including the destination subscriber address information to the selected exchange, even if the accommodation destination of the other party's subscriber terminal is changed, it will not be lost and will be received. Will be possible.

In the present invention, there are two address systems, a subscriber address and a candidate list (intra-network address) that is used as a key to identify an exchange that is a candidate for accommodation in the network. For one subscriber address, two or more candidates for the original accommodation destination and a predetermined accommodation replacement destination can be obtained, and the accommodation destination of the other party's subscriber terminal can be searched from among these candidates. Since it is possible to do so, even if there is a relocation of the subscriber terminal of the other party, this is done for a predetermined exchange station,
Since it is always accommodated in the above-mentioned candidate exchange station, it becomes possible to receive the call at the other party's subscriber terminal.

As described above, according to the present invention, it is possible to select two or more exchanges having a possibility of accommodating as a candidate for one subscriber address. Since the destination terminal is searched and connected, even if the accommodation station of the subscriber terminal is changed, the calling subscriber terminal side connects and communicates without being aware of the accommodation change of the destination subscriber terminal. Will be able to.

Further, a plurality of accommodating line numbers are made to correspond to accommodating line numbers in the addressee subscriber address information in advance as a connection candidate at the exchange, and when an incoming call request is received, the addressee address information is included in the addressee subscriber address information. From the connection candidates corresponding to the accommodation line number of 1), the subscriber terminal of the accommodation line number selected in the scheduled order is made to receive the call and the line is connected. Therefore, even if incoming calls are concentrated on a terminal with a specific accommodation line number, it is possible to make a call to a terminal with another registered accommodation line number that is a candidate for connection, so that it is possible to avoid a situation in which communication cannot be performed during a call. Therefore, the service can be improved.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a subscriber address representing a subscriber terminal and an intra-network address representing a line connecting a switching center of a network system and a terminal accommodated in the switching center are used.
When one address system is adopted and two or more addresses in the network are made to correspond to one subscriber address and the switching center accommodating the subscriber terminal is changed, the subscriber terminal in the network is The present invention is characterized in that it is possible to connect to a subscriber terminal whose accommodation exchange has been changed without changing the destination subscriber address. Hereinafter, embodiments of the present invention will be described with reference to the drawings. .

(Embodiment 1) FIG. 1 is a diagram showing an example of a network for explaining the present invention. In FIG.
3 are switching stations, 10-12, 20-22, 30-, respectively.
32 are subscriber terminals, respectively. The exchanges 1 to 3 are connected to each other via communication lines L1, L2 and L3. Also,
Switching center 1 accommodates subscriber terminals 10-12, switching center 2 accommodates subscriber terminals 20-22, and switching center 3 accommodates subscriber terminals 30-32.

L10 to L12 are subscriber lines, which are provided corresponding to the subscriber terminals 10 to 12, respectively, and are communication lines connecting the exchange 1 and the subscriber terminals 10 to 12. Similarly, L20 to L22 are subscriber lines, which are communication lines provided corresponding to the subscriber terminals 20 to 22 and connecting the exchange 2 and the subscriber terminals 20 to 22, respectively, and also L30 to L32. It is a subscriber line, and is a communication line that is provided corresponding to each of the subscriber terminals 30 to 32 and connects the exchange 3 and the subscriber terminals 30 to 32.

In each of the exchanges 1 to 3, in order to connect the lines between the subscriber terminals accommodated in the exchanges, the exchanges are provided with station numbers, and the subscriber lines for connecting the subscriber terminals are provided with terminal lines. A number is assigned and the above-mentioned station number and terminal line number are used as subscriber addresses for determining the destination. This is the same as the conventional one.

Then, when a dial call is made from the subscriber terminal to issue a connection request to the exchange station accommodated therein, a connection request signal containing dial information (destination subscriber address) is given to the exchange station and exchanged. From the destination subscriber address included in this connection request signal, the station knows which exchange station accommodates the destination subscriber terminal, By transmitting the connection request signal containing the subscriber address, the switching center accommodating the destination subscriber terminal receiving the request sends the connection request signal from the subscriber address to the connected subscriber line of the destination subscriber terminal. It has a function of knowing the terminal line number and controlling the incoming call to the subscriber line of the terminal line number.

As described above, the exchange station accommodating the destination subscriber terminal can be searched from the destination subscriber address because the subscriber address system normally indicates the accommodation exchange station and the accommodation line. This is because it is composed of the terminal line number indicating the number, and by this, the originating exchange can know which exchange accommodates the subscriber only by looking at the station number of the destination subscriber number.

Each of the exchanges 1 to 3 accommodates a subscriber terminal via a subscriber line, but when a failure occurs in a certain exchange, it is accommodated in the failure-caused exchange. The subscriber terminal can be accommodated in another healthy exchange.

In this system, in the case of this accommodation change,
For advance which mobile switching center or to which switching center accommodating place, are predetermined target. For example, in the example of FIG. 1, the accommodating subscriber terminal of the switching center 2 is replaced by the switching center 3 as shown by the dotted line.

In the system of the present invention, with respect to the accommodation exchange station (station number; subscriber station number) information in the destination subscriber address, the exchange station to which the accommodation is exchanged is determined in order, and the candidate station number table (search table for each station number) in priority order ). In the priority order, the highest candidate station number is the original accommodation exchange station information (station number information), and the next candidate station number is the first accommodation exchange destination exchange station information (station number information).

FIG. 2A shows an example of the format of the destination subscriber address ADR in the connection request signal. Figure 2
In (a), S is a subscriber station number section, in which station number information indicating the subscriber station is stored. Further, T is an accommodated line number portion, in which an accommodated line number indicating a terminal line number is stored.

The configuration format of the destination subscriber address information portion ADR including the subscriber station number portion S and the accommodated line number portion T is no different from the conventional format. However, in the present invention, the station number of the subscriber station number section S is used as a search key for the above-mentioned station number candidate station number table which is a search list,
This is different from the prior art in that the configuration adopts the system of the in-network address of the candidate sequential selection method described below.

That is, in the present invention, a candidate station number table for each station number is prepared in the exchange, and in this table, as shown in FIG.
1 and S2 are registered. Further, in the present invention, the candidate station number is known in the exchange station by using the station number obtained in the subscriber station number section S in the destination subscriber address as a key, and the connection partner station can be sequentially searched using this candidate station number. ing.

In this way, the candidate station number corresponding to this station number is known using the station number obtained in the subscriber station number section S as a key, and the switching center corresponding to the candidate station number is notified of the terminal line number in the destination subscriber address. The method of trying to receive an incoming call at a communication terminal is used. With such a station number as a key, a candidate station number corresponding to this station number is set in advance so that the partner station can be searched in the candidate station number. Internal address system.

The candidate station numbers S1 and S2 are not the station numbers themselves obtained at the subscriber station number section S, but are the station numbers indirectly obtained at the exchange side using this station number S as a key. The internal station number is used. The in-network station number is a number corresponding to the exchange station, and the in-network station number is the exchange station number (station number) and 1
Corresponding to one-to-one. Therefore, as a result, the highest priority candidate station number S1 is the same station number as that obtained in the subscriber station number section S, and when a connection request is issued to the exchange station of this station number and the connection fails, the next order The configuration is such that a connection request is issued to the exchange station with the candidate station number S2 to attempt connection.

In the present invention, when a failure occurs in an exchange, it is defined in advance which exchange will accommodate the subscriber terminal accommodated in the faulty exchange, and the accommodating subscriber of the particular exchange will receive it. By configuring the terminal so that it can be accommodated and exchanged only in a specific exchange, two or more candidate station numbers to be assigned to the station number of the subscriber address can be registered in advance in each exchange as candidates.

When each exchange receives one subscriber address, it uses the station number stored in the subscriber station number section S in the subscriber address ADR as a key to correspond to this station number in advance in the exchange. By using two or more candidate station numbers S1, S2, ... Set and registered as candidates, it is possible to try which candidate station number of the exchange station can receive the call. Even in this case, it is possible to find the desired subscriber terminal and connect to it.

Next, the operation of the present system having such a configuration will be described. In the system configuration of FIG. 1, the operation will be described, for example, in the case where the subscriber terminal 10 makes a connection request to the subscriber terminal 20.

In order to make a connection request to the subscriber terminal 20, the subscriber address AD of the subscriber terminal 20 is sent from the subscriber terminal 10.
Dial R. Here, the subscriber address ADR of the subscriber terminal 20 consists of the subscriber station number S and the accommodating line number T, but the connection request is an exchange in which the connection request signal including the subscriber address ADR is accommodated in the subscriber terminal 10. This is done by sending to station 1. This subscriber address A
As shown in FIG. 2A, the DR is composed of a station number section S indicating a subscriber station and a terminal line number section T indicating a terminal line number. In the present invention, in constructing the system, two or more candidate station numbers are assigned to one subscriber station number and connection requests can be issued to these candidates, and the candidate station numbers assigned as this candidate are: It is intended for the exchange station which is set as the accommodation exchange target of the accommodated subscriber terminal in the exchange station having the subscriber station number.

Then, for example, with respect to the switching center 2 in which the subscriber terminal 20 is accommodated, when a failure occurs in the switching center 2, a target capable of accommodating the accommodating subscriber terminal in the switching center 2 is replaced. If it is set as station 3, the exchange station 2 is set as a candidate station number corresponding to the station number of the exchange station 2.
Candidate station number NS2 indicating the exchange number and the candidate station number NS indicating the exchange station 3
Two of the three will be assigned to the candidate station number table for each station number of the exchange 1. The priority of allocation is the original accommodation exchange office first, and then the exchange office that exchanges accommodations is next.
Similarly, the table of the exchange 3 is also allocated according to this example.

Therefore, the exchange station 1 accommodating the subscriber terminal 10 stores the storage station number of the subscriber station number section S (exchange station 2 in the subscriber address ADR obtained from the subscriber terminal 10).
Station number NS2, which is the first candidate (first candidate) of the exchange that may accommodate the subscriber.
Is first selected and a connection request signal including the subscriber address ADR obtained from the subscriber terminal 10 is issued to the corresponding exchange 2 and if the connection cannot be established, the next candidate station number NS
3 and selects the subscriber terminal 1 to the corresponding exchange 3.
The control mode is such that a connection request signal including the subscriber address ADR obtained from 0 is issued.

A concrete operation example will be described with reference to the operation transition diagram of FIG. In the system operated in the configuration of FIG. 1, the exchange 2 is now in trouble, and as shown in FIG. 4, the subscriber terminals 20, 21,
It is assumed that 22 has been accommodated in the exchange 3. In this state, the connection operation will be described by taking the case where the subscriber terminal 10 makes a call to the subscriber terminal 20 as an example. The subscriber terminal 10 dials the subscriber address ADR of the subscriber terminal 20 as usual. Good. As a result, a call request is made from the subscriber terminal 10, and a connection request signal including the subscriber address ADR is sent to the exchange 1 (S21).

The subscriber terminal 20 is assigned to the subscriber address ADR.
Number information S and accommodation line number T of the switching center accommodating
In response to this, the exchange 1 looks at the exchange number information S in the subscriber address ADR, and the exchange number candidate, which is a search list, is held by itself as to which exchange is the candidate of the accommodation destination. Check from the station number table. As a result, the candidate station number NS2 indicating the exchange 2 with respect to the storage station number of the station number information S
Then, the candidate station number NS3 indicating the exchange 3 is registered.

Then, the exchange 1 first selects the candidate station number NS2, which is the first candidate, and sends a connection request to the exchange 2 corresponding to the candidate station number NS2. However, the exchange 2 cannot transmit because of a failure (S22).

Then, the exchange 1 selects the next candidate candidate station number NS3 and sends a connection request to the exchange 3 corresponding to the candidate station number NS3 (S23). Since the exchange 3 is normal, it receives this connection request. Then, the exchange 3 which has received this searches the subscriber terminal 20 from the terminal line number stored in the accommodated line number portion T of the subscriber address ADR included in the connection request signal. Since the subscriber terminal 20 is accommodated in the exchange 3, the exchange 3 finds the subscriber terminal 20 and sends an incoming call signal to the subscriber terminal 20 (S24).

The subscriber terminal 20 receiving the incoming call signal notifies the incoming call, and thereafter, the automatic response of the subscriber terminal 20 or the response operation of the user returns a response from the subscriber terminal 20 to the exchange 3. Further, this response is sent from the exchange 3 to the subscriber terminal 10 via the exchange 1 to complete the call connection (S25 to S27).

In the above, the case where the exchange 2 fails is explained as an example, but the same applies to the case where the exchange 2 is not a fault and the communication line connecting the exchange 2 and another exchange is faulty. . Also, in the case of a failure of another switching center or a communication line connecting the switching centers, the call connection can be similarly made.

Also, the terminal line number of one terminal is stored in the accommodated line number portion T of the subscriber address ADR, but the terminal line number of one terminal corresponds to the terminal line number of one or more terminals. It is also possible to set a line number as a connection destination candidate including the priority order of connection so that the line number can be selected in the destination exchange. In this way, it is possible to control one terminal line number in the destination exchange station so that the one with the highest priority is tried to receive, and the first candidate destination subscription determined from the destination subscriber address. It is possible to connect to another subscriber terminal different from the subscriber terminal.
This realizes the representative selection function.

An example of a system to which this representative selection function is applied will be described as a second embodiment. (Embodiment 2) In the system to which the representative selection function is applied, the accommodation line numbers of a plurality of subscriber terminals that enable incoming calls are made to correspond to the accommodation line numbers of the subscriber addresses.
For one accommodation line number, select a connectable one from the accommodation line number group of connection candidates.

In order to do this, each switching center is provided with FIG.
A terminal selection candidate table as shown in (c) is prepared. That is, with respect to the accommodation line number indicating the terminal line number stored in the accommodation line number portion T of the destination subscriber address ADR, the accommodation line number Ta of the first selection candidate terminal and the accommodation line number Tb of the next-order selection candidate terminal In addition, the accommodation line number of the selection candidate terminal is registered in the order of the accommodation line number Tc of the selection candidate terminal, and the accommodation line number portion T of the destination subscriber address ADR is stored in the exchange. The selection candidate terminal can be searched using the terminal selection candidate table using the line number as a key.

Here, the accommodation line number (terminal line number) of the subscriber terminal 20 is N20, the accommodation line number of the subscriber terminal 21 (terminal line number) is N21, and the accommodation line number of the subscriber terminal 22 (terminal line number). ) Is N22.

Now, the subscriber terminals 20, 21, 22 are accommodated in the original exchange 2 and the subscribers accommodated in the exchange 1 while the exchange 2 is operating normally. Consider a case in which the terminal 10 wants to talk to any one of the subscriber terminals 20, 21, and 22 to which the representative selection function is applied.

In this case, when a call is made from the subscriber terminal 10 and a connection request is issued to the exchange station in which the subscriber terminal 10 is accommodated,
A connection request signal including dial information (destination subscriber address) is given to the exchange 1. For example, it is assumed that the accommodated line number N20 of the subscriber terminal 20 is used as the dial information.

At this time, the call request signal from the subscriber terminal 10 includes the information of the station number indicating the exchange 2 and the destination subscriber address in which the terminal line number N20 of the subscriber terminal is inserted. The call request signal is transmitted to the exchange 1. The exchange 1 which receives this, as in the first embodiment,
The candidate station number table classified by station number registered in the exchange station is used to perform a table search by using the station number information indicating the exchange station 2 of the destination subscriber addresses in the call request signal as a search key to find the candidate station number. know.

According to the first embodiment, the candidate station number in the destination subscriber address in this case indicates the exchange station 2 or the exchange station 3, but since the first candidate station number is the exchange station 2, the exchange station 1
First, a call request signal is transmitted to the exchange 2.

The exchange 2 receives this call request signal and receives the terminal line number N of the subscriber terminal at the destination subscriber address.
Looking at 20, the accommodation line to which the subscriber terminal is connected is searched using the terminal selection candidate table.

In this case, the terminal line number of the subscriber terminal is N
As a result of the search, the exchange 2 knows that the subscriber terminals 20, 21, 22 correspond to the terminal line number N20.

The switching center 2 is the subscriber terminal 2 which is the receiving target.
Subscriber terminal 20 which is the first candidate among 0, 21, 22
Is selected to check whether or not this subscriber terminal 20 is empty. As a result, if it is free,
Send an incoming call signal. This incoming call causes the subscriber terminal 20
Sends a response, the subscriber terminal 10 receives the response, and the connection is completed.

When the subscriber terminal 20 is selected and it is checked whether or not the subscriber terminal 20 is free, if the subscriber terminal 20 is not free, the next candidate subscriber terminal 21 is selected. Then, it is checked whether or not this subscriber terminal 21 is empty. As a result, if it is empty, an incoming call signal is transmitted to the subscriber terminal 21. By this incoming call, the subscriber terminal 21 sends a response, the subscriber terminal 10 receives the response, and the connection is completed.

When the subscriber terminal 21 is selected and it is checked whether or not the subscriber terminal 21 is vacant, if the subscriber terminal 21 is not vacant, the candidate subscriber terminals 22 are successively selected.
Is selected to check whether or not this subscriber terminal 22 is empty. As a result, if it is free,
Send an incoming call signal. This incoming call causes the subscriber terminal 22
Sends a response, the subscriber terminal 10 receives the response, and the connection is completed.

In this way, the terminal line number of the subscriber terminal at the destination subscriber address is used as a key to search for the subscriber terminal of the incoming call by using the terminal selection candidate table, and the relevant subscriber terminal is searched for by the determined procedure. The subscriber terminal 20, which is the target of the incoming call,
One of 21 and 22 is selected and an incoming call signal is transmitted to the selected subscriber terminal. After the call is received, a response is sent from the selected subscriber terminal, and the exchange of the subscriber terminal 10 receives this response via the exchange so that the connection with the subscriber terminal 10 is completed. I chose

As described above, in the second embodiment, with respect to the terminal line number of one subscriber terminal, the accommodating line numbers of a plurality of subscriber terminals are assigned as connectable subscriber lines, and the assigned plurality of subscriber lines are assigned. By selecting one of the subscriber lines in accordance with a predetermined procedure and receiving the call, it is possible to make a plurality of terminals connectable to the terminal line number of the one subscriber terminal. Therefore, it is possible to avoid continuation of busy conversation due to the concentration of incoming calls on a specific terminal, and it is possible to improve the service.

The present invention is not limited to the embodiments described above and shown in the drawings, but can be appropriately modified and carried out within the scope of the invention. Although various embodiments have been described above, in short, the present invention is a network including a plurality of exchange stations connected by communication paths and capable of mutual communication transmission, and subscriber terminals accommodated in each of these exchange stations. In the system, when a failure occurs in a certain switching center, the subscriber terminal accommodated in the failed switching center is transferred to another switching center to enable communication, and the other party obtained from the calling subscriber terminal Using the destination subscriber address of the destination subscriber terminal, specify the accommodating switching center and issue a connection request, select the corresponding subscriber terminal at the specified switching center in accordance with this request, receive the call, and connect the line. In a network system that enables communication, a switching center to which accommodation is to be changed in the event of a failure of the switching center is predetermined, and each switching center is assigned to each switching center specified from the destination subscriber address. The list information of the planned accommodation exchanges including the specified exchange destination exchange shall be retained, and the schedule shall be followed according to this list from the information of the destination subscriber address obtained from the subscriber terminal when a call is made from the subscriber terminal. It is characterized in that the exchanges are selected in this order, and a connection request including the destination subscriber address information is issued to the selected exchanges.

Further, a plurality of accommodating line numbers are made to correspond to accommodating line numbers in the destination subscriber address information in advance as a connection candidate at the exchange, and when the incoming call request is received, the destination subscriber address information is received. It is characterized in that the subscriber terminal of the accommodation line number selected in a predetermined order from the connection candidates corresponding to the accommodation line number in the middle is received and the line is connected.

The present invention is a network system comprising a plurality of exchange stations connected by communication paths and capable of mutually communicating and transmitting, and subscriber terminals accommodated in each of these exchange stations. When a failure occurs, it is intended for a system that allows the subscriber terminal accommodated in the faulty switching center to be transferred to another switching center and communicate with it. The destination subscriber address, which is the destination subscriber terminal accommodating exchange number and the accommodation line number of the destination subscriber terminal, is used as the connection destination information, and the accommodating exchange station of the destination subscriber terminal is indicated by the station number information. A specific connection request is issued, and in accordance with this request, the corresponding subscriber terminal is selected and received at the specified exchange, and line connection is made to enable communication.

In the present invention, it is planned that the exchange stations of the accommodation replacement destinations in the event of a failure of the exchange offices are determined in advance, and that each exchange office includes the determined exchange destination exchange offices for each exchange station number. The list information of the destination exchanges is held, the exchanges are selected in the scheduled order from the information of the destination subscriber address obtained from the subscriber terminal when the subscriber terminal makes a call, and the selected exchanges are selected. Issue a connection request to the station containing the destination subscriber address information.

According to the present invention, since the accommodation exchange office at the time of failure occurrence is predetermined in each exchange office, the candidate of the exchange office to which the connection request should be issued from the information of the destination subscriber address is scheduled. According to the list of accommodation exchanges, select in the order scheduled. Then, by issuing a connection request including the destination subscriber address information to the selected exchange, even if the accommodation destination of the other party's subscriber terminal is changed, it will not be lost and will be received. Will be possible.

As described above, according to the present invention, it is possible to select two or more exchanges having a possibility of accommodating destinations as candidates for one subscriber address, and in the network, the other parties are sequentially selected from the candidates. Since the destination terminal is searched and connected, even if the accommodation station of the subscriber terminal is changed, the calling subscriber terminal side connects and communicates without being aware of the accommodation change of the destination subscriber terminal. Will be able to.

Further, a plurality of accommodating line numbers are made to correspond to accommodating line numbers in the destination subscriber address information in advance as a connection candidate at the exchange, and when the incoming call request is received, the destination subscriber address information is included. From the connection candidates corresponding to the accommodation line number of 1), the subscriber terminal of the accommodation line number selected in the scheduled order is made to receive the call and the line is connected. Therefore, even if incoming calls are concentrated on a terminal with a specific accommodation line number, it is possible to make a call to a terminal with another registered accommodation line number that is a candidate for connection, so that it is possible to avoid a situation in which communication cannot be performed during a call. Therefore, the service can be improved.

[0083]

As described above, according to the present invention,
There is a possibility of accommodation for one subscriber address 2
One or more exchanges can be selected as candidates, and the destination terminal is searched from among these candidates in the network to connect to each other. In this case, the calling subscriber terminal side can connect and communicate without being aware of the accommodation change of the destination subscriber terminal. Further, the representative selection processing can be performed by performing the same processing.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention,
FIG. 1 is a system configuration diagram for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining an embodiment of the present invention,
The figure explaining the address system applied by this invention.

FIG. 3 is a diagram for explaining an embodiment of the present invention,
FIG. 6 is an operation transition diagram for explaining an operation example of the present invention.

FIG. 4 is a diagram for explaining an embodiment of the present invention,
The figure which shows the example of a system at the time of a switching center failure in the system of this invention.

FIG. 5 is a system configuration diagram for explaining a conventional example.

FIG. 6 is a diagram for explaining a conventional example, which is an operation transition diagram for explaining an example of the operation in the conventional system.

FIG. 7 is a diagram for explaining a conventional example, which is an operation transition diagram for explaining an example of the operation in the conventional system.

[Explanation of symbols]

1, 2, 3 ... Exchange station 10, 11, 12, 20, 21, 21, 22, 30, 31, 3
2 ... Subscriber terminal ADR ... Subscriber address L1, L2, L3 ... Communication line L10-L12, L20-L22, L30-L32 ... Subscriber line

Claims (2)

[Claims] 1. A network system comprising a plurality of exchanges connected by a communication path and capable of mutual communication and transmission, and subscriber terminals accommodated in these exchanges, wherein a failure occurs at a certain exchange. At the same time, the subscriber terminal accommodated in this faulty exchange is accommodated in another exchange to enable communication, and the destination subscriber address of the destination subscriber terminal obtained from the calling subscriber terminal is used. , In the network system that specifies the accommodating switching center, issues a connection request, selects the corresponding subscriber terminal at the specified switching center to receive the call, and connects the line to enable communication. In the event of a failure, the transfer center of the transfer destination will be defined in advance, and each switch will include the transfer center of the transfer destination specified for each switch specified from the destination subscriber address. To keep a list information of the accommodating exchange stations, in accordance with the list from the destination subscriber address information derived from the subscriber terminal when a call from the subscriber terminal,
A circuit switching connection method for a network system, characterized in that switching stations are selected in a scheduled order and a connection request including destination subscriber address information is issued to the selected switching stations. 2. The switching center preliminarily associates a plurality of accommodation numbers with the accommodation numbers in the destination subscriber address information as connection candidates and accommodates the destination subscriber address information when a call reception request is received. 2. The circuit-switched connection method for a network system according to claim 1, wherein the subscriber terminal having the accommodation number selected in a predetermined order from the connection candidates corresponding to the line number is made to receive a line connection.