JPH07221838A - Switching network with detour function - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a switching network capable of relieving a call in the event of congestion or failure. In a switching network having a relay exchange 3 through which a call passes, the terminal number to which the call is to be connected is set for each destination terminal in the relay exchange when the route for connecting to the destination terminal 9 is unavailable. When the registered registration means 23 is connected and the route is unusable, the transit exchange makes a detour or alternate reception connection to the terminal previously registered in the registration means via another route 15. To do. In addition, by dialing a special number including a preregistered private number from any terminal, a virtual private connection for connecting to a specific terminal corresponding to the number or a specific extension terminal accommodated in a specific private branch exchange The above configuration is applied to network services.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a virtual private network (hereinafter referred to as VPN) service in a switching network such as a telephone, which has a function of performing a detour or an alternate reception at the time of congestion of a relay line, etc. It is about.

[0002]

2. Description of the Related Art Conventionally, there has been a private network in which a plurality of PBXs (private branch exchanges) are connected by a dedicated line, but there are drawbacks that the cost becomes high depending on the traffic volume and the flexibility of changing the network configuration is lacking. It was Therefore, a service has been provided in which a plurality of PBXs are connected to a public communication network and a virtual private communication network, that is, a VPN is constructed on the public communication network. In addition, domestic telecommunications carriers and overseas telecommunications carriers have cooperated, enabling the construction of international VPNs. Figure 2
FIG. 3 is a block diagram showing an example of an international communication network that provides an international VPN service. The PBX 1 registered in the international VPN service is connected to the subscriber line exchange 2 of the public network via the subscriber line 11, and the subscriber line exchange 2 further connects to the trunk line 1.
It is connected to the international repeater exchange 3 via 2. The international relay exchange 3 is connected to a foreign international relay exchange 5 via an international relay line 13 and is also connected to a database 4. It is assumed that the foreign network has the same structure as the domestic network.

Here, at the terminal 10 accommodated in the foreign PBX 8 registered in the international VPN, an extension telephone number arbitrarily set (registered) corresponding to the domestic terminal 9 is dialed. Then, the PBX 8 converts the extension number into a special number plus extension number and calls the public network.
The call is connected to the international repeater exchange 5, and the exchange 5 requests the database 6 to retrieve the identification information of the partner terminal to be connected from the calling number and the extension number. Database 6
Performs the search, and returns, as a response, information as to whether the calling subscriber is registered in the service and, if registered, identification information of the partner terminal to be connected. The international relay exchange 5 creates a called terminal identification number in the international relay line 13 called an intermediate number from the identification information and transfers it to the domestic international relay exchange 3 via the international relay line 13. Here, what is converted into an intermediate number is that the call is not a normal call but a VPN service call.
This is so that the can be recognized.

When the exchange 3 receives the intermediate number of the VPN service call, it issues a search request to the database 4, and the database 4 converts the intermediate number into a domestic telephone number including the extension number of the terminal to receive the call. The exchange 3 relays the call based on this telephone number, and the trunk line 12, the domestic subscriber exchange 2,
An incoming call is made to the target terminal 9 via the subscriber line 11 and the PBX 1. With the configuration and operation as described above, for example, by dialing the arbitrarily determined location number + domestic extension number of PBX 1 from the foreign terminal 10,
It becomes possible to connect to the domestic terminal 9.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the PN service, for example, the trunk line 12 between the international trunk exchange 3 and the subscriber line exchange 2 due to an increase in communication volume,
Alternatively, the subscriber line 11 between the subscriber line exchange 2 and the PBX 1
Is congested, the international transit exchange 3 disconnected the international transit line. Therefore, in a private network using a leased line, calls can always be connected within a certain amount of traffic, whereas with VPN services, users can call even though the amount of communication between both PBXs is small. There was a problem that could not be connected. Further, there is also a problem that communication becomes impossible if any one of the relay line 12, the subscriber line exchange 2, the subscriber line 11 and the PBX 1 becomes a failure. An object of the present invention is to solve the above-mentioned problems of the prior art and provide a switching network capable of relieving a call in the event of congestion or failure.

[0006]

According to a first aspect of the present invention, in a switching network having a transit exchange through which a call passes, the transit exchange is provided with registration means for preregistering a detour number designating a detour route for each terminal. When the route for connecting to the receiving terminal is unusable, the transit exchange connects to the terminal via the detour route of the detour number registered in advance in the registration means. .

According to the second aspect of the invention, by dialing a preregistered extension telephone number from a terminal accommodated in the private branch exchange, it is accommodated in another private branch exchange corresponding to the extension telephone number. In a VPN service switching network for connecting to a specific extension terminal, a relay exchange through which a VPN service call passes is provided with registration means for previously registering a detour number designating a detour route for each terminal receiving the service, and the other means. When the route for connecting to the private branch exchange is unusable, the transit exchange connects to the terminal via the detour route by the detour number designating the detour route registered in advance in the registration means. It is characterized by performing.

[0008]

According to the first and second aspects of the present invention, since an arbitrary detour number can be registered for each terminal, it is possible to make an incoming call to the same terminal via another route (for example, another company's network) at the time of congestion. It is also possible to have a completely different terminal act as a substitute. According to the second invention, for example, VP
If the telephone number of the PBX registered in the N service via the other company's network is registered in the registration means, if the route between the transit exchange and the PBX is congested or there is a failure, a VPN call will be sent to another company. It is possible to make an incoming call to the same PBX via another route such as a communication network. Also, if the other company's network can transfer to the extension number, it is possible to call the same terminal. Therefore, the loss rate of the VPN service call is reduced and the quality of the service is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an international VPN service will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing in detail a part of a communication network such as a telephone or ISDN to which the present invention is applied, and corresponds to the domestic part of FIG. 2 (the same devices as those in FIG. is there.). The extension line terminal 9 and the reception board 17 are accommodated in the speech path switch of the PBX 1 registered in the VPN service, and the subscriber line 11 from the subscriber line exchange 2 is accommodated.
It is also connected to the subscriber line 24 of the communication network 15 of another company. The PBX 1 has a function of receiving extension telephone number information from a subscriber line switch when receiving a call, for example, by a multi-frequency signal,
The function allows the extension terminal 9 to receive an incoming call directly. The extension number information can be received via a common line signaling system signal line or ISDN D channel.

The subscriber line exchange 2 accommodates a subscriber line 11 and a relay line 12, and its central control unit (hereinafter referred to as CC) is connected to a relay unit 19 by a control signal line (shown by a dotted line in FIG. 1). ing. The international relay exchange 3 accommodates a relay line 12, another company's relay line 25, an international relay line 13 and a relay line 26 with the service processing exchange 16, and its CC is connected to a relay device 18 by a control signal line. . The service processing switch 16 is a switch provided for a special service, and is equipped with a signal device 20 for accommodating the relay line 26 from the international relay switch 3 and transmitting and receiving various signals (sounds), and a voice synthesis function, It is equipped with a talkie device for sending out announcements and the like. The CC of the exchange 16 is also connected to the relay device 18. The relay devices 18 and 19 are, for example, common line signaling system packet switching devices, and include Cs of the respective switching devices including those from overseas.
The call control data such as the telephone number exchanged between the Cs is transferred to the CC of the target exchange.

The CC of the service exchange 16 is connected to the search device 22 of the database 4, and the search device 22 is connected to the search device 22.
Searches the registration data stored in the data memory 23 in order to convert the intermediate number of the VPN call received from overseas into the receiving terminal number, for example. In the data memory 23, various data regarding the subscriber who registered the service is registered.

Next, the operation will be described. FIG. 3 is a flowchart showing an example of processing of each device in the public network. Figure 3
In the figure, the left side shows the CC processing of the international relay exchange 3, the center shows the service processing exchange 16, and the right side shows the processing of the database 4 (search device 22). When an international VPN call from the foreign exchange 5 arrives at the international transit exchange 3, the exchange 3 recognizes from the number information (an intermediate number different from a normal call) that this is a VPN call, and in step S1, service processing is performed. Transfers the call to the exchange 16. In step S2, the service processing exchange 16
Recognizes that the received call is a VPN call, and edits the search request information to be transmitted to the database 4 in step S3. This information includes the intermediate number for VPN service received from abroad. In step S4, this search request information is transferred to the database 4, and V
Make a PN call verification request.

The search device 22 of the database 4 receives the collation request in step S5, and in step S6 searches the registered data in the data memory 23 using the intermediate number as a key, and the intermediate number is registered in the VPN service. If it is registered, the telephone number of the terminal that should receive the call is calculated. This telephone number is, for example, PBX1
This is the telephone number of the company's network including up to the extension number of. In step S7, if the intermediate number is not registered, the database 4 returns a response without registration, and the service processing exchange 16 disconnects the call, but if it is a valid number, returns the retrieved telephone number. To do. In step S8, the service processing exchange 16 transfers the received telephone number to the international relay exchange 3. In step S9,
The international relay exchange 3 calls the corresponding terminal 9 based on the received telephone number.

Normally, by this processing, the subscriber's line exchange 2 and PBX 1 are controlled by the telephone number including the extension number to call the target terminal 9, and when the terminal 9 responds, the international relay exchange 3 makes a call from a foreign country. Call line and the terminal 9
The trunk line connected to is connected and the call is started. However, in step S10, when a call disconnection response is received from the exchange on the way for some reason, the information is transferred to the service processing exchange 16. In step S11, the service processing exchange 16 analyzes the disconnection cause information included in the disconnection response, and checks whether or not the disconnection cause is congestion. If the cause is not congestion such as busy, the process goes to step S20 to disconnect the foreign side line and open the line. However, if the reason is congestion, the process shifts to step S12 to issue a detour number search request to the database 4.

The database 4 receives the detour number search request in step S13, and searches again by the intermediate number in step S14. In step S15, it is checked whether or not the detour number is registered. If it is not registered, the process proceeds to step S20 and the call is disconnected. If it is registered, the process proceeds to step S16 and the number is deleted. Will be returned. The detour number to be registered is arbitrary, but it is sufficient if the route and terminal can be identified according to the detour route. For example, the communication network 1 of another company connected to the PBX 1
5 is the telephone number corresponding to the subscriber line 24. The service processing exchange 16 transfers the detour telephone number to the international relay exchange 3 in step S17, and then in step S17.
At 18, the international repeater exchange 3 calls the terminal 9, which is a detour terminal, through the trunk line 25 and the network of another company based on the received detour telephone number. In this case, in order to call the terminal 9 directly, it is necessary to be able to transfer the extension number to the PBX 1 even in the network of another company, and if the representative number is registered as the detour number, the call is received at the reception desk 17 and transferred. It will be.

With the above processing, for example, a call that cannot be connected due to congestion in the company's network can be relieved by passing through another company's network or another company's network.
The quality of PN service is improved.

Although the embodiment has been described above, the present invention may be modified as follows. First, in the first search processing step S6 of the database 4 in FIG. 3, the detour telephone number can be searched together and returned to the service processing exchange 16. In this way, the second search processing (steps S12 to S16) is not necessary, and the service processing exchange 16 can immediately shift from step S11 to step S17.

The service processing switch 16 is a switch provided for performing various special service processes other than the VPN service, but with respect to this VPN service, it merely performs a relay process of data. Therefore,
When the international transit exchange 3 performs the processing performed by the service processing exchange 16 of FIG. 3, the service processing exchange 16 can be omitted. In this case, the database 4 is directly connected to the international transit exchange 3. The database 4 can be used by a plurality of exchanges. In this embodiment, a call does not pass through the service processing exchange 16 during a call, but for example, a signal tone is sent every time a predetermined time elapses, a call is disconnected after a predetermined call time elapses, or a special billing service, etc. The call may be connected via the service processing switch 16 to implement the other services of.

Although this embodiment relates to the detour of a VPN call, this technical idea can be applied to a normal call, and the call loss rate can be reduced by registering the detour terminal. Although an example of telephone communication is shown, the invention can be applied to a data communication network or an image network such as FAX.

[0020]

According to the first and second aspects of the present invention, since an arbitrary detour number can be registered for each terminal, an incoming call is made to the same terminal via another route (for example, another company's network) at the time of congestion. It is also possible to have a completely different terminal act as a substitute. Therefore, there is an effect that the call loss rate is reduced, the detour destination can be freely selected for each terminal, and the service is improved. According to the second aspect of the invention, for example, if the telephone number of the PBX registered in the VPN service via the other company's network is registered in the registration means, the relay exchange and P
When the route between BXs is congested or has a failure, a VPN call can be made to arrive at the same PBX via another route such as a communication network of another company. Also, if the other company's network can transfer to the extension number, it is possible to call the same terminal. Therefore, the loss rate of the VPN service call is reduced and the quality of the service is improved. There is also an effect of promoting the use of the service. In addition, the number conversion device for VPN service can be used as it is, and the equipment can be effectively used.

[Brief description of drawings]

FIG. 1 is a block diagram showing in detail a part of a communication network to which the present invention is applied.

FIG. 2 is a block diagram showing an international communication network that provides a VPN service.

FIG. 3 is a flowchart showing a process of each device in the public network.

[Explanation of symbols]

1, 8 ... Private branch exchange, 2, 7 ... Subscriber line exchange, 3, 5
… International transit switch, 4,6… Database, 9,10…
Terminal, 11 ... Subscriber line, 12 ... Trunk line, 13 ... International trunk line, 15 ... Other company's network, 16 ... Service processing exchange, 17 ...
Reception desk, 18, 19 ... Relay device

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04Q 3/64 9370-5K

Claims (4)

[Claims] 1. A switching network having a relay exchange through which a call passes, wherein the relay exchange is provided with registration means for preregistering a detour number designating a detour route for each terminal, and a route for connecting to a receiving terminal is provided. A switching network having a bypass function, characterized in that, when the relay switch cannot be used, the relay switch connects to the terminal via the bypass route of the bypass number registered in the registration means. 2. A connection to a specific extension terminal corresponding to the extension telephone number, which is accommodated in another private branch exchange, by dialing an extension telephone number registered in advance from a terminal accommodated in the private branch exchange. In the virtual private network service switching network for performing the above, a registration means for preregistering a detour number designating a detour route for each terminal receiving the service is provided in the transit exchange through which the virtual private network service call passes, and the other private branch exchange. When the route for connecting to the terminal is unusable, the transit exchange may connect to the terminal via the detour route by the detour number designating the detour route registered in the registration means. A switching network with a characteristic detour function. 3. The switching network having a bypass function according to claim 1, wherein the registered detour number is a number corresponding to a terminal other than the original called terminal. 4. The virtual private network service is an international virtual private network service, the transit exchange accommodates an international line, and is a number for converting an intermediate number representing a virtual private network service call into a telephone number in the international line. Equipped with conversion means,
The number conversion means includes the registration means for outputting the converted number and the detour number designating the detour route at the same time, the relay exchange and the route are own switching networks, and the detour route is a switching network of another company. The switching network having a bypass function according to claim 2, wherein the switching network has a bypass function.