JP2019145991A - Telephone exchange system, exchanger, telephone exchange method, and program - Google Patents

Abstract

To connect a telephone on a call origination side with a telephone on a call incoming side with a route in which no loop is generated even when a detour and automatic transfer are generated.SOLUTION: A telephone exchange system comprises a plurality of exchangers connected to a network. An exchanger, in the case of transmitting a call connection request signal to another exchanger, adds an ID of the exchanger to the call connection request signal before transmitting the call connection request signal. An exchanger, in the case of receiving a call connection request signal, checks whether or not the exchanger's own ID is included in the call connection request signal and, when it is detected that the exchanger's own ID is included, determines that a loop is generated to return a call connection request reject signal to an exchanger in the previous stage from which the call connection request signal is transmitted. An exchanger that detects that the exchanger's own ID is included in a call connection request signal and returns a call connection request reject signal transmits a call connection request signal to another exchanger on another route.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a telephone exchange system, an exchange, a telephone exchange method, and a program.

  There is known a telephone exchange system in which a plurality of exchanges such as base stations and relay stations (for example, IP-PBX (Internet Protocol Private Branch Exchange)) are connected via a network (see, for example, Patent Documents 1 and 2).

  In a telephone exchange system in which a plurality of IP-PBXs are connected by a network, a detour route is set in advance to divert a call in case of a network failure between IP-PBXs. In addition to the detour when a network failure occurs, a telephone accommodated in one IP-PBX can be used as a call forwarding destination for automatic forwarding such as call forwarding. May be set. For this reason, a call passing through a route that was not assumed at the time of system construction may be generated by these detours and automatic transfer.

  Further, in the IP-PBX according to the related technology, independent processing is performed for each of detour and automatic transfer. Therefore, if the relay station is in a state in which a call can be generated (for example, there is a vacant resource as IP-PBX, is not subject to restrictions on IP-PBX service, etc.), the relay station follows the set route. The call is relayed to perform diversion and automatic transfer. For this reason, the caller's telephone and the callee's telephone are connected via a relay route that passes through one relay station more than once, and the resources of the relay station may be wasted. . In the following, returning to the original relay station while the relay route passes through a plurality of relay stations is referred to as a loop.

  Also, if a number of calls like the above occur and the resource consumption of the relay station increases, the relay station will run out of resources and cannot make or receive other calls to be performed. Will occur. For this reason, the resources of the peripheral relay station and the bandwidth of the network connecting the IP-PBX may be wasted.

  For example, a network device such as a switch has a function of detecting the occurrence of a loop in which frame data transmitted by itself returns to itself. However, in the case of IP-PBX, even if a loop occurs, call control data transmitted by IP-PBX becomes new data every time it passes through IP-PBX. For this reason, the IP-PBX cannot detect whether the data sent by itself has returned to itself, that is, cannot detect that a loop has occurred, in the same manner as the network device.

  In SIP (Session Initiation Protocol), a via header is prepared in the SIP message for loop detection, and the route through which the SIP message has passed can be confirmed from the information in the via header. However, in the case of IP-PBX, every time a SIP message passes through IP-PBX, IP-PBX generates a new SIP message, and when sending a SIP message to the subsequent IP-PBX, the information of the via header is Cannot be taken over. Therefore, the IP-PBX cannot perform loop detection using the via header.

JP 2001-156789 A Japanese National Patent Publication No. 11-510349

  As described above, an exchange such as IP-PBX according to the related technology cannot detect the occurrence of a loop even when a loop occurs in a relay route due to detouring and automatic transfer. Was connected to the called phone. As a result, there has been a problem that the resources of the exchange and the bandwidth of the network connecting the exchanges are wasted.

  An object of the present disclosure is to provide a telephone exchange system that can solve the above-described problems and can connect a calling telephone and a called telephone through a route that does not cause a loop even if detouring and automatic forwarding occur. An exchange, a telephone exchange method, and a program are provided.

A telephone exchange system according to one aspect is:
It has multiple switches connected to the network,
When the exchange transmits a call connection request signal to another exchange, it adds the ID of its own exchange to the call connection request signal, and transmits the call connection request signal.
The exchange that has received the call connection request signal checks whether the call connection request signal includes the ID of its own exchange, and if it detects that the ID of its own exchange is included, a loop has occurred. The call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
The exchange that detects that the ID of the local exchange is included in the call connection request signal and returns a call connection request rejection signal transmits the call connection request signal to another exchange on another route.

An exchange according to one aspect is
A transceiver,
A processor coupled to the transceiver,
The processor is
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.

The telephone exchange method according to one aspect is:
A telephone exchange method using an exchange connected to a network,
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.

The program according to one aspect is
In the computer that becomes the exchange,
When transmitting a call connection request signal to another exchange, a procedure for adding the ID of the local exchange to the call connection request signal and transmitting the call connection request signal;
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. A procedure for determining and returning a call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal;
A procedure for transmitting a call connection request signal to another switch on another route when detecting that the ID of the local exchange is included in the call connection request signal and returning a call connection request rejection signal;
Is a program for executing

  According to the above-described aspect, even if detouring and automatic transfer occur, a telephone exchange system, an exchange, and a telephone exchange method that can connect a calling telephone and a called telephone on a route in which a loop does not occur And an effect that a program can be provided.

It is a figure showing an example of 1 composition of a telephone exchange system concerning an embodiment. It is a figure which shows an example of the telephone exchange method which concerns on a comparative example. It is a sequence diagram which shows the sequence of the telephone exchange method which concerns on the comparative example shown in FIG. It is a figure which shows an example of the telephone exchange method which concerns on embodiment. It is a sequence diagram which shows the sequence of the telephone exchange method which concerns on embodiment shown in FIG. It is a block diagram which shows one structural example of the relay station which concerns on embodiment.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description and drawings are omitted and simplified as appropriate for clarity of explanation. In the following drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary.

First, a configuration example of the telephone exchange system according to the present embodiment will be described. FIG. 1 is a diagram showing a configuration example of a telephone exchange system according to the present embodiment.
As shown in FIG. 1, the telephone exchange system according to the present embodiment includes relay stations 10-A, 10-B, and 10-C, base stations 20-1 and 20-2, and an extension telephone 30-11. , 30-21, 30-B1. Hereinafter, when referring to the relay stations 10-A, 10-B, and 10-C without particular distinction, they may be simply referred to as “relay stations 10”. Similarly, the base stations 20-1 and 20-2 may be simply referred to as “base station 20”, and the extension telephones 30-11, 30-21, and 30-B1 may be simply referred to as “extension telephone 30”. is there.

  Although FIG. 1 shows three relay stations 10 and two base stations 20, the number of relay stations 10 and base stations 20 is not limited to the example of FIG. The relay station 10-B accommodates the extension telephone 30-B1, the base station 20-1 accommodates the extension telephone 30-11, and the base station 20-2 accommodates the extension telephone 30-21. However, the extension telephone 30 accommodated in the relay station 10 and the base station 20 is not limited to the example of FIG.

The relay station 10 and the base station 20 are exchanges realized by IP-PBX, for example.
However, in the present embodiment, the following control processing is added to relay station 10 in addition to the control processing executed by a normal exchange.

When the relay station 10 transmits call control data (call connection request signal) to another relay station 10 or the base station 20 in order to request a call connection, the relay station 10 through which the call control data has passed The station ID of the own station is added as the relay station information shown. In the following description, it is assumed that the call control data is an SIP message INVITE request.
Specifically, the relay station 10 adds its own station ID as the transit station information to the unique header of the INVITE request, and transmits the INVITE request to the other relay station 10 or the base station 20.

When the relay station 10 receives the INVITE request, the relay station 10 checks whether or not a unique header is added to the INVITE request. When the relay station 10 detects that the unique header is added to the INVITE request, the relay station 10 checks whether or not the own station ID is included in the transit station information of the unique header.

When the relay station 10 detects that its own station ID is included in the INVITE request, the relay station 10 determines that a loop has occurred in the relay route and restricts incoming calls (to reject a call connection request). ), A response code “482 Loop Detected” (call connection request rejection signal) of the SIP message is returned to the preceding relay station 10 or base station 20 that has transmitted the INVITE request.

-When the relay station 10 detects that the station ID of its own station is included in the INVITE request and returns a response code “482 Loop Detected” of the incoming call restriction, another relay station 10 or base station on another route An INVITE request is transmitted to 20.

  If the station ID of the relay station 10 is not included in the INVITE request, the relay station 10 executes a normal process of transmitting (relaying) the INVITE request based on the INVITE request.

When the relay station 10 receives an incoming call restriction response code “482 Loop Detected”, the relay station 10 returns an incoming call restriction response code “482 Loop Detected” to the preceding relay station 10 or base station 20 that has transmitted the INVITE request. To do.

After the relay station 10 returns the response code “482 Loop Detected” of the incoming call restriction, it is used to transmit / receive the INVITE request to / from the preceding relay station 10 or the base station 20 that has transmitted the INVITE request. Free up resources.

Subsequently, the telephone exchange method according to the present embodiment will be described below, and the telephone exchange method according to a comparative example will be described for comparison with the present embodiment. In any of the telephone exchange methods, the telephone exchange system has a configuration shown in FIG.
In any telephone exchange method, a call is made from the extension telephone 30-11 accommodated in the base station 20-1 to the extension telephone 30-B1 accommodated in the relay station 10-B. Assumed to be performed. In any of the telephone exchange methods, relay is performed via the relay station 10-A as a detour route when a failure occurs in the network of the route that can directly connect the base station 20-1 and the relay station 10-B. It is assumed that a route for connecting to the station 10-B is set in advance. In any telephone exchange method, call extension (automatic transfer) is set in the extension telephone 30-B1, and the extension telephone 30 accommodated in the base station 20-2 as a transfer destination at the time of call transfer. Assume that -21 is specified.

  First, a telephone exchange method according to a comparative example will be described. FIG. 2 is a diagram illustrating an example of a telephone exchange method according to a comparative example. FIG. 3 is a sequence diagram showing a sequence of the telephone exchange method according to the comparative example shown in FIG. 2 and 3, the same step number is assigned to the same step.

As shown in FIGS. 2 and 3, first, from the extension telephone 30-11 accommodated in the base station 20-1, the extension telephone 30-B1 accommodated in the relay station 10-B is set as the destination. Make a call.
However, here, a failure has occurred in the network of the route that can directly connect the base station 20-1 and the relay station 10-B. Therefore, the base station 20-1 performs connection switching to a preset detour route. Here, a route for connecting to the relay station 10-B via the relay station 10-A is set in advance as a bypass route.

  Therefore, the base station 20-1 connects to the relay station 10-A and transmits an INVITE request to the relay station 10-A in order to connect to the extension telephone 30-B1 through a preset detour route (step S1). S101).

  In order to connect to the extension telephone 30-B1, the relay station 10-A connects to the relay station 10-B and transmits an INVITE request to the relay station 10-B (step S102). This INVITE request is an INVITE request newly generated by the relay station 10-A.

  The relay station 10-B receives the INVITE request from the relay station 10-A, but the extension telephone 30-B1 sets the absent transfer (automatic transfer). Therefore, the relay station 10-B performs connection switching for connecting to the extension telephone 30-21 that is a transfer destination at the time of the absent transfer based on the absent transfer setting.

  Therefore, the relay station 10-B connects to the relay station 10-C and transmits an INVITE request to the relay station 10-C in order to connect to the extension telephone 30-21 (step S103). This INVITE request is an INVITE request newly generated by the relay station 10-B, and it is added that the new destination is the extension telephone 30-21.

  In order to connect to the extension telephone 30-21, the relay station 10-C connects to the relay station 10-A and transmits an INVITE request to the relay station 10-A (step S104). This INVITE request is an INVITE request newly generated by the relay station 10-A.

  The relay station 10-A receives the INVITE request from the relay station 10-C, but the received INVITE request does not include the transit station information. For this reason, the relay station 10-A cannot detect that the relay route starting from the local station passes through the relay station 10-A twice and a loop is generated. Therefore, the relay station 10-A connects to the base station 20-2 and connects to the base station 20-2 in order to connect to the extension telephone 30-21 despite the occurrence of a loop in the relay route. An INVITE request is transmitted (step S105).

  As a result, since the extension telephone 30-11 on the calling side and the extension telephone 30-21 on the called side are connected through the relay route that passes through the relay station 10-A twice, the relay station 10-A In spite of a single call, resources for two calls are consumed.

  Subsequently, a telephone exchange method according to the present embodiment will be described. FIG. 4 is a diagram showing an example of a telephone exchange method according to the present embodiment. FIG. 5 is a sequence diagram showing a sequence of the telephone exchange method according to the present embodiment shown in FIG. In FIG. 4 and FIG. 5, the same step number is assigned to the same step.

As shown in FIGS. 4 and 5, first, from the extension telephone 30-11 accommodated in the base station 20-1, the extension telephone 30-B1 accommodated in the relay station 10-B is set as the destination. Make a call.
However, here, a failure has occurred in the network of the route that can directly connect the base station 20-1 and the relay station 10-B. Therefore, the base station 20-1 performs connection switching to a preset detour route. Here, a route for connecting to the relay station 10-B via the relay station 10-A is set in advance as a bypass route.

  Therefore, the base station 20-1 connects to the relay station 10-A and transmits an INVITE request to the relay station 10-A in order to connect to the extension telephone 30-B1 through a preset detour route (step S1). S201).

  The relay station 10-A connects to the relay station 10-B in order to connect to the extension telephone 30-B1. At this time, the relay station 10-A diverts the INVITE request received from the base station 20-1, and in order to indicate that the INVITE request has passed through its own station, in the unique header of the INVITE request, The station ID (A) of its own station is added, and the INVITE request is transmitted to the relay station 10-B (step S202). The INVITE request at this time is in a state where the station ID of the relay station 10-A is added as the relay station information (X-Forwarding-Info: A).

  The relay station 10-B receives the INVITE request from the relay station 10-A, but the extension telephone 30-B1 sets the absent transfer (automatic transfer). Therefore, the relay station 10-B performs connection switching for connecting to the extension telephone 30-21 that is a transfer destination at the time of the absent transfer based on the absent transfer setting.

  Therefore, the relay station 10-B connects to the relay station 10-C in order to connect to the extension telephone 30-21. At this time, the relay station 10-B needs to take over the information that the INVITE request is an incoming call from the extension telephone 30-11. Therefore, the relay station 10-B diverts the INVITE request received from the relay station 10-A to indicate that the new destination is the extension telephone 30-21 and that the relay station 10-B has been passed. Is added to the unique header of the INVITE request, and the INVITE request is transmitted to the relay station 10-C (step S203). The INVITE request at this point is in a state in which the two station IDs of the relay stations 10-A and 10-B are added as the relay station information (X-Forwarding-Info: A, B).

  The relay station 10-C connects to the relay station 10-A in order to connect to the extension telephone 30-21. At this time, similarly to the relay station 10-B, the relay station 10-C diverts the INVITE request received from the relay station 10-B and indicates the station ID (C ) Is added to the unique header of the INVITE request, and the INVITE request is transmitted to the relay station 10-A (step S204). The INVITE request at this point is in a state in which the station IDs of the three stations, relay stations 10-A, 10-B, and 10-C, are added as transit station information (X-Forwarding-Info: A, B, C). ).

  The relay station 10-A receives the INVITE request from the relay station 10-C, but the received INVITE request includes the station ID of the relay station 10-A as the transit station information. For this reason, the relay station 10-A detects that the station ID of the relay station 10-A is included in the INVITE request, determines that a loop has occurred in the relay route, and relays the preceding stage that has transmitted the INVITE request. A response code “482 Loop Detected” of the SIP message is returned to the station 10-C in order to restrict incoming calls (step S205). After the relay station 10-A returns the response code “482 Loop Detected” of the incoming call restriction, the relay station 10-A releases the resources used for transmission / reception of the INVITE request with the relay station 10-C.

  When receiving the response code “482 Loop Detected” from the relay station 10-A, the relay station 10-C receives the response code “482 Loop”. "Detected" is returned (step S206). Similarly, the relay station 10-B also returns an incoming call restriction response code “482 Loop Detected” to the preceding relay station 10-A (step S207). After returning 482 Loop Detected of incoming call restriction, the relay station 10-C releases resources used for transmission / reception of the INVITE request with the relay station 10-B. Similarly, the relay station 10-B releases resources used for transmission / reception of the INVITE request with the relay station 10-A.

  Thereafter, the relay station 10-A transmits an INVITE request to another relay station 10 or the base station 20 on another route (step S208). 4 and 5, the relay station 10-A transmits an INVITE request to the base station 20-2, and specifies the connection destination of the resource used for transmission / reception of the INVITE request with the base station 20-1. The relay station 10-B is changed to the base station 20-2 which is another route. As a result, it is possible to connect the extension telephone 30-11 on the calling side and the extension telephone 30-21 on the called side through another relay route in which no loop has occurred.

  As described above, according to the present embodiment, when the relay station 10 transmits an INVITE request to another relay station 10 or the base station 20, the relay station 10 adds its own station ID to the INVITE request. Further, when receiving the INVITE request, the relay station 10 checks whether or not the station ID of the own station is included in the INVITE request. If the station ID of the relay station 10 is included in the INVITE request, the relay station 10 determines that a loop has occurred in the relay route, and restricts incoming calls to the preceding relay station 10 or base station 20 that has transmitted the INVITE request. “482 Loop Detected” is returned, and an INVITE request is transmitted to another relay station 10 or base station 20 on another route.

  As described above, when transmitting the INVITE request, the relay station 10 adds its own station ID to the INVITE request. When receiving the INVITE request, the relay station 10 determines whether the INVITE request includes the station ID of its own station. Accordingly, it is determined whether or not a loop has occurred in the relay route. Therefore, when a loop occurs in the relay route due to detouring and automatic transfer of the INVITE request, it can be detected that the loop has occurred.

  In addition, when a loop occurs in the relay route, the relay station 10 returns the incoming call restriction to the preceding relay station 10 or the base station 20 that has transmitted the INVITE request, and rejects the call connection, while the other route. An INVITE request is transmitted to the other relay station 10 or base station 20 above. Therefore, it is possible to connect the extension telephone 30 on the calling side and the extension telephone 30 on the called side through a relay route in which no loop occurs.

  Therefore, even if the detouring and automatic transfer of the INVITE request occur, the calling side extension telephone 30 and the called side extension telephone 30 can be connected via a relay route in which no loop has occurred. As a result, it is possible to prevent the resources of the relay station 10 from being wasted and the bandwidth of the network connecting the relay stations 10 and the network connecting the relay station 10 and the base station 20 being wasted. Can do.

  Further, when the relay station 10 receives the incoming call restriction “482 Loop Detected”, the relay station 10 returns the incoming call restriction “482 Loop Detected” to the preceding relay station 10 or the base station 20. Further, after returning the response code “482 Loop Detected” of the incoming call restriction, the relay station 10 releases the resources used for transmission / reception of the INVITE request with the relay station 10 or the base station 20 in the preceding stage. Therefore, the resource used in the relay route in which the loop has occurred can be used for another route and the resources can be used efficiently.

Subsequently, a configuration example of the relay station 10 described in the above embodiment will be described below. FIG. 6 is a block diagram illustrating a configuration example of the relay station 10.
As shown in FIG. 6, the relay station 10 includes a transceiver 101, a processor 102, and a memory 103.
The transceiver 101 is used to communicate with another relay station 10, the base station 20, or the extension telephone 30. The transceiver 101 may include a plurality of transceivers. Transceiver 101 is coupled to processor 102.

  The memory 103 is configured to store a software module (computer program) including an instruction group and data for performing processing by the relay station 10 described in the above embodiment. The memory 103 may be configured by a combination of a volatile memory and a nonvolatile memory, for example.

  The processor 102 is configured to read out and execute a software module (computer program) from the memory 103 to perform the processing of the relay station 10 described in the above embodiment. The processor 102 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). The processor 102 may include a plurality of processors.

  The processor 102 executes one or a plurality of programs including a group of instructions for causing a computer to execute the algorithm of the relay station 10 described in the above embodiment. This program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Compact Disc-Read Only Memory), CDs. -R (CD-Recordable), CD-R / W (CD-ReWritable), semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)) Including. Further, the program may be supplied to the computer by various types of temporary computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

  Although illustration and description of the configuration of the base station 20 described in the above embodiment are omitted, the base station 20 has the same configuration as the configuration of the relay station 10 shown in FIG. May be.

  Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  For example, in the above embodiment, when a loop occurs in the relay route, the relay station that detects the occurrence of the loop transmits an INVITE request to another relay station or base station on another route. However, it is not limited to this.

  Instead of the above, the relay station that detects the occurrence of the loop returns the incoming call restriction to the base station that is the source of the INVITE request, and uses the resources used for sending and receiving the INVITE request with the base station. You may release. In this case, the base station that has received the incoming call restriction from the relay station may output an alarm that a loop has occurred in the relay route. This prompts maintenance personnel to redesign the relay route, and can be expected to improve the design so that loops do not occur in the relay route. Alternatively, the base station that has received the incoming call restriction from the relay station may try a call connection on another route, or may restrict outgoing calls from the extension telephone that has made the call.

A part or all of the above embodiments can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
It has multiple switches connected to the network,
When the exchange transmits a call connection request signal to another exchange, it adds the ID of its own exchange to the call connection request signal, and transmits the call connection request signal.
The exchange that has received the call connection request signal checks whether the call connection request signal includes the ID of its own exchange, and if it detects that the ID of its own exchange is included, a loop has occurred. The call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
The exchange that detects that the ID of the local exchange is included in the call connection request signal and returns the call connection request rejection signal transmits the call connection request signal to another exchange on another route.
Telephone exchange system.
(Appendix 2)
The exchange that has received the call connection request rejection signal returns a call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal.
The telephone exchange system according to attachment 1.
(Appendix 3)
After the call connection request rejection signal is returned, the exchange releases resources used for transmission / reception of the call connection request signal with the previous exchange that has transmitted the call connection request signal.
The telephone exchange system according to appendix 2.
(Appendix 4)
The call connection request signal and the call connection request rejection signal are SIP messages.
The telephone exchange system according to any one of appendices 1 to 3.
(Appendix 5)
The call connection request signal is a SIP message INVITE request,
The call connection request rejection signal is a response code “482 Loop Detected” of the SIP message.
The telephone exchange system according to appendix 4.
(Appendix 6)
A transceiver,
A processor coupled to the transceiver,
The processor is
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.
switch.
(Appendix 7)
When the processor receives the call connection request rejection signal, the processor returns the call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal.
The exchange according to appendix 6.
(Appendix 8)
After returning the call connection request rejection signal, the processor releases resources used to transmit / receive the call connection request signal to / from the previous exchange that has transmitted the call connection request signal.
The exchange according to appendix 7.
(Appendix 9)
A telephone exchange method using an exchange connected to a network,
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.
Telephone exchange method.
(Appendix 10)
When a call connection request rejection signal is received, a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
The telephone exchange method according to appendix 9.
(Appendix 11)
After returning the call connection request rejection signal, release the resources used for transmission / reception of the call connection request signal with the previous exchange that has transmitted the call connection request signal,
The telephone exchange method according to attachment 10.
(Appendix 12)
In the computer that becomes the exchange,
When transmitting a call connection request signal to another exchange, a procedure for adding the ID of the local exchange to the call connection request signal and transmitting the call connection request signal;
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. A procedure for determining and returning a call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal;
A procedure for transmitting a call connection request signal to another switch on another route when detecting that the ID of the local exchange is included in the call connection request signal and returning a call connection request rejection signal;
A program for running
(Appendix 13)
In the computer,
When a call connection request rejection signal is received, a procedure for returning the call connection request rejection signal to the previous exchange that has transmitted the call connection request signal is further executed.
The program according to attachment 12.
(Appendix 14)
In the computer,
After the call connection request rejection signal is returned, a procedure for releasing resources used for transmission / reception of the call connection request signal to / from a previous exchange that has transmitted the call connection request signal is further executed.
The program according to attachment 13.

10-A, 10-B, 10-C Relay station 101 Transceiver 102 Processor 103 Memory 20-1, 20-2 Base station 30-B1, 30-11, 30-21 Extension telephone

Claims (10)

It has multiple switches connected to the network,
When the exchange transmits a call connection request signal to another exchange, it adds the ID of its own exchange to the call connection request signal, and transmits the call connection request signal.
The exchange that has received the call connection request signal checks whether the call connection request signal includes the ID of its own exchange, and if it detects that the ID of its own exchange is included, a loop has occurred. The call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
The exchange that detects that the ID of the local exchange is included in the call connection request signal and returns the call connection request rejection signal transmits the call connection request signal to another exchange on another route.
Telephone exchange system. The exchange that has received the call connection request rejection signal returns a call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal.
The telephone exchange system according to claim 1. After the call connection request rejection signal is returned, the exchange releases resources used for transmission / reception of the call connection request signal with the previous exchange that has transmitted the call connection request signal.
The telephone exchange system according to claim 2. A transceiver,
A processor coupled to the transceiver,
The processor is
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.
switch. When the processor receives the call connection request rejection signal, the processor returns the call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal.
The exchange according to claim 4. After returning the call connection request rejection signal, the processor releases resources used to transmit / receive the call connection request signal to / from the previous exchange that has transmitted the call connection request signal.
The exchange according to claim 5. A telephone exchange method using an exchange connected to a network,
When transmitting a call connection request signal to another exchange, the ID of the local exchange is added to the call connection request signal, and the call connection request signal is transmitted.
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. Judgment is made and a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
When it is detected that the ID of the local exchange is included in the call connection request signal and the call connection request rejection signal is returned, the call connection request signal is transmitted to another exchange on another route.
Telephone exchange method. When a call connection request rejection signal is received, a call connection request rejection signal is returned to the preceding exchange that has transmitted the call connection request signal.
The telephone exchange method according to claim 7. After returning the call connection request rejection signal, release the resources used for transmission / reception of the call connection request signal with the previous exchange that has transmitted the call connection request signal,
The telephone exchange method according to claim 8. In the computer that becomes the exchange,
When transmitting a call connection request signal to another exchange, a procedure for adding the ID of the local exchange to the call connection request signal and transmitting the call connection request signal;
When a call connection request signal is received, it is checked whether the call connection request signal includes the ID of the local exchange. If it is detected that the ID of the local exchange is included, a loop has occurred. A procedure for determining and returning a call connection request rejection signal to the preceding exchange that has transmitted the call connection request signal;
A procedure for transmitting a call connection request signal to another switch on another route when detecting that the ID of the local exchange is included in the call connection request signal and returning a call connection request rejection signal;
A program for running

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