JP5930547B2 - Session control server and operation method thereof - Google Patents

Description

  The present invention relates to a session control server and an operation method thereof.

  In a conventional communication system, one session control server is associated with a terminal, and a signal transmitted from the terminal is received by the session control server and is signaled according to subscriber data held in the session control server. The method of processing is adopted.

  By the way, in a communication system, it may be necessary for another session control server to receive a signal and process the signal according to the subscriber data held in the session control server.

  In such a case, changing the former state to the latter state is called “server migration”, the former session control server is called the migration source server, and the latter server is called the migration destination server. In addition, the terminal in this case is referred to as a migration target terminal.

  For example, in the setting of a transfer device that receives a signal from a terminal to be migrated, it has already been changed so that the signal from that terminal should be transmitted to the destination session control server. In such a period when subscriber data is not held, the destination session control server does not have subscriber data even if a signal from the terminal is transmitted via the transfer device. The signal needs to be transferred to the original session control server.

  For example, in the communication system disclosed in Patent Document 1, in the migration destination server, a flag indicating that a migration target terminal is a migration target is associated, and a terminal that is not a migration target is not a migration target. The flag shown is matched, and it is determined whether or not it is a migration target by the flag. If it is the migration target, the signal transmitted to the migration destination server is transferred to the migration source server, and in this way Continue communication services.

JP 2010-193367 A

  However, in the communication system disclosed in Patent Document 1, in the migration source server, the setting change is made so that the signal from the migration target terminal should be transmitted to the migration destination server, and the migration destination server A flag must be set, and these maintenance operations must be performed in conjunction. For example, if a signal from a terminal to be migrated is processed in a state where only one of them is implemented, there is a possibility that the routing is incorrect and cannot be processed correctly. Further, since maintenance work is required for each of the migration source and the migration destination, a large number of maintenance operations are required when there are a large number of terminals to be migrated.

  In addition, if a flag indicating whether or not to be a transition target is provided and whether or not to be a transition target is determined based on the flag, a signal delay occurs correspondingly. However, unless a determination is made, it is not possible to determine whether the target is a transition target or not. Therefore, a signal delay also occurs for a terminal that is not the transition target, and the processing between the terminals that are not the transition target is affected.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique that does not affect processing between terminals that are not the migration target during the migration of the session control server. is there.

  In order to solve the above-described problem, the first aspect of the present invention provides a state in which a transfer source session control server should receive a signal from a terminal via a transfer device, and a signal from the terminal via the transfer device. A session control server used as a migration destination session control server when the migration destination session control server makes a transition to a state to be received, wherein the transfer device includes the terminal and the migration source session control server. If the correspondence is stored, the signal from the terminal is transmitted to the migration source session control server, and after the correspondence is changed to the correspondence between the terminal and the migration destination session control server, , And transmits a signal from the terminal to the session control server of the transfer destination, and the session control server subscribes via a communication line. Connected to a data server, the subscriber data server stores the correspondence relationship between the terminal and the session control server that is the migration source, and the correspondence relationship with the terminal at a time later than the change in the transfer device. The session control server is changed to a correspondence relationship of the migration destination session control server, the session control server receives a response signal to the request signal from the transfer device, and the signal reception unit is the transfer device. If a response signal to the request signal is received from the transfer device even though the request signal is not transmitted to any of the transfer devices, which session control server should receive the signal transmitted from the terminal to the subscriber data server. A session to receive a signal transmitted from the terminal from the subscriber data server. If the notification receiving unit that receives the notification indicating the server control server, the determination unit that determines whether the session control server indicated in the notification is itself, or the session control server indicated in the notification is not itself A signal transmission unit that transmits the response signal to the session control server indicated in the notification; and a signal discard unit that discards the response signal if the session control server indicated in the notification is itself. It is characterized by.

  According to the second aspect of the present invention, the transfer destination session control server receives the signal from the terminal via the transfer device and the state from which the transfer source session control server should receive the signal from the terminal via the transfer device. An operation method of a session control server used as a destination session control server in the case of transition to a power state, wherein the transfer device stores a correspondence relationship between the terminal and the source session control server If there is a signal from the terminal, the signal from the terminal is transmitted to the session control server of the migration source, and after the correspondence relationship is changed to the correspondence relationship of the terminal and the session control server of the migration destination, To the destination session control server, and the session control server connects to the subscriber data server via a communication line. The subscriber data server stores the correspondence relationship between the terminal and the migration source session control server, and at a later time than the change in the transfer apparatus, the subscriber data server changes the correspondence relationship between the terminal and the migration destination. In the operation method, the signal reception unit of the session control server receives a response signal to the request signal from the transfer device, and the session control server inquires. If the signal reception unit has received a response signal to the request signal from the transfer device even though the signal reception unit has not transmitted the request signal to the transfer device, the signal is transmitted from the terminal to the subscriber data server. Which session control server should receive the signal to be received, and the notification receiving unit of the session control server receives the subscriber A notification indicating the session control server that should receive the signal transmitted from the terminal, and the determination unit of the session control server determines whether the session control server indicated in the notification is itself Determining, if the session control server indicated by the notification is not itself, the signal transmission unit of the session control server transmits the response signal to the session control server indicated by the notification, and the signal of the session control server The discard unit discards the response signal if the session control server indicated in the notification is itself.

  ADVANTAGE OF THE INVENTION According to this invention, it can avoid affecting the process between the terminals which are not transfer object during transfer of a session control server.

1 shows a configuration of a communication system including a session control server according to the present embodiment. An example of the setting in a subscriber data server is shown. An example of the setting in a transfer apparatus is shown. The function block of the session control server of a transfer destination is shown. An example of the operation | movement sequence of a communication system is shown. The flow of a process in the session control server of a transfer destination is shown. Another trigger for starting the processing after step S203 in FIG. 6 is shown. An example of the setting in a comparative example is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, in the communication system according to the present embodiment, a subscriber data server 1 is connected to session control servers 21, 22, and 23 via communication lines. The session control servers 21, 22, and 23 are connected to each other via a communication line. The session control server 21 is connected to a transfer device 31 via a communication line, and the transfer device 31 is connected to a terminal 41 and other terminals via a communication line. The session control server 22 is connected to the transfer device 32 via a communication line, and the transfer device 32 is connected to the terminal 42 and other terminals via the communication line. The session control server 23 is connected to transfer devices 32 and 33 via a communication line, and the transfer device 33 is connected to a terminal 43 and other terminals via a communication line. Note that the number of session control servers, transfer devices, and terminals is not limited to this example.

  For example, it is determined that the signal transmitted from the terminal 41 should be received by the session control server 21, and the signal transmitted from the terminal 42 is determined to be received by the session control server 22. It is determined that the signal transmitted from the terminal 43 should be received by the session control server 23.

  However, in the future, it is determined that the signal transmitted from the terminal 42 should be received by the session control server 23. That is, among the terminals 41, 42, and 43, only the terminal 42 is the object to be transferred. is there.

  As shown in FIG. 2, in the subscriber data server 1, for each terminal, setting is made as to which session control server should receive a signal transmitted from the terminal. Hereinafter, such a setting is referred to as a correspondence relationship between the terminal and the session control server. For example, the subscriber data server 1 has a correspondence relationship between the terminal 41 and the session control server 21, a correspondence relationship between the terminal 42 and the session control server 22, and a correspondence relationship between the terminal 43 and the session control server 23. In addition, the subscriber data server 1 has subscriber data used for each terminal.

  As shown in FIG. 3, for example, in the transfer device 32, for each terminal connected to itself, a setting is made as to which session control server should receive a signal transmitted from the terminal. Hereinafter, such a setting is referred to as a correspondence relationship between the terminal and the session control server. For example, the transfer device 32 has a correspondence relationship between the terminal 42 and the session control server 22.

  Although not shown, other transfer apparatuses also have a correspondence relationship between the terminal and the session control server for each connected terminal.

  As shown in FIG. 4A, the session control server 23 includes a signal receiving unit 231 that receives a response signal for a request signal from a transfer device, and which session control server receives a signal from a terminal that is a transmission source of the response signal. An inquiry unit 232 that inquires the subscriber data server 1 whether to receive, or a notification reception unit that receives from the subscriber data server 1 a notification indicating the session control server that should receive the signal from the terminal that is the transmission source of the response signal. 233, a determination unit 234 that determines whether or not the session control server indicated in the notification is the session control server 23, a signal transmission unit 235 that transmits a response signal to the session control server indicated in the notification, and discards the response signal A signal discarding unit 236, and a subscriber data storage unit 2 for storing subscriber data relating to a terminal connected to the terminal via a transfer device Equipped with a 7.

  As shown in FIG. 4B, in the subscriber data storage unit 237, for each terminal connected to the session control server 23 via a transfer device, subscriber data relating to that terminal is stored. For example, the subscriber data storage unit 237 has already stored the subscriber data related to the terminal 43 for the terminal 43, but has not yet stored the subscriber data for the terminal 42 to be transferred.

  Although not shown, subscriber data is also associated with each terminal in other session control servers. For example, the session control server 22 has subscriber data regarding the terminal 42.

  As shown in FIG. 5, for example, the administrator or the like changes the correspondence between the terminal 42 and the session control server 22 to the correspondence between the terminal 42 and the session control server 23 with respect to the transfer device 32 (S1: FIG. 3). That is, the session control server migration related to the terminal 42 is started in this way, for example.

  On the other hand, the terminal 41 transmits an INVITE signal with the transmission source and the transmission destination as the terminals 41 and 42 to the transfer device 31 connected to the terminal 41 in order to make a call with the terminal 42 as before the start of the transition. (S11).

  Since the transfer device 31 has a correspondence relationship between the terminal 41 and the session control server 21, the transfer device 31 transmits an INVITE signal to the session control server 21 (S13).

  Since the session control server 21 does not have the subscriber data of the terminal 42, the session control server 21 inquires of the subscriber data server 1 which session control server should receive the signal from the terminal 42 (S15).

  Since the subscriber data server 1 has a correspondence relationship between the terminal 42 and the session control server 22, the subscriber data server 1 transmits a notification indicating the session control server 22 to the session control server 21 (S17).

  The session control server 21 transmits an INVITE signal to the session control server 22 indicated in the notification (S19).

  Since the session control server 22 has the subscriber data regarding the terminal 42, the session control server 22 does not transmit the INVITE signal to other session control servers, but transmits it to the transfer device 32 connected to itself (S21).

  The transfer device 32 transmits the INVITE signal to the terminal 42 that is the transmission destination (S23).

  The terminal 42 transmits a 200 OK signal (response signal of the INVITE signal) having the transmission source and the transmission destination to the terminals 42 and 41, respectively, to the transfer device 32 connected to the terminal 42 (S31).

  In step S1, the transfer device 32 changes the correspondence between the terminal 42 and the session control server 21 to the correspondence between the terminal 42 and the session control server 23, and therefore transmits a 200 OK signal to the session control server 23 (S33). .

  Since the session control server 23 has not transmitted the INVITE signal to the transfer device 32 but has received the 200 OK signal from the transfer device 32, the session control server 23 sends to the subscriber data server 1 from the terminal 42 that is the transmission source of the 200 OK signal. Which session control server should receive this signal (S35).

  Since the subscriber data server 1 has a correspondence relationship between the terminal 42 and the session control server 22, the subscriber data server 1 transmits a notification indicating the session control server 22 to the session control server 23 (S37).

  The session control server 23 transmits a 200 OK signal to the session control server 22 indicated in the notification (S39).

  Since the session control server 22 does not have the subscriber data of the terminal 41 to which the 200 OK signal is transmitted, the session control server 22 inquires the subscriber data server 1 which session control server should receive the signal from the terminal 41 ( S41).

  Since the subscriber data server 1 has a correspondence relationship between the terminal 41 and the session control server 21, the subscriber data server 1 transmits a notification indicating the session control server 21 to the session control server 22 (S43).

  The session control server 22 transmits a 200 OK signal to the session control server 21 indicated in the notification (S45).

  In step S35, the session control server 23 inquires of the subscriber data server 1 which session control server should receive the signal from the terminal 41, and the response, that is, the signal from the terminal 41 is sent to the session control server. The response that 21 should be received may be notified to the session control server 22 in step S39. Thereby, steps S41 and S43 can be omitted.

  Since the session control server 21 has the subscriber data of the terminal 41, the session control server 21 does not transmit the 200OK signal to the other session control server, but transmits it to the transfer device 31 connected to itself (S47).

  The transfer device 31 transmits the 200 OK signal to the terminal 41 that is the transmission destination (S49).

  Thereafter, the request signal such as the INVITE signal is treated in the same manner as the INVITE signal, while the response signal such as the 200 OK signal is treated in the same manner as the 200 OK signal. The call is made. At that time, the session control server 21 uses the subscriber data of the terminal 41, and the session control server 22 uses the subscriber data of the terminal 42.

  On the other hand, for example, at a preset time, the terminal 42 transmits a REGISTER signal whose transmission source is the terminal 42 to the transfer apparatus 32 connected to the terminal 42 (S101).

  Since the transfer device 32 has a correspondence relationship between the terminal 42 and the session control server 23, the transfer device 32 transmits a REGISTER signal to the session control server 23 (S103).

  Since the session control server 23 has received the REGISTER signal, the session control server 23 transmits a signal requesting the subscriber data of the terminal 42 that is the transmission source to the subscriber data server 1 (S105).

  Since the subscriber data server 1 receives the signal requesting the subscriber data of the terminal 42, the subscriber data server 1 shows the correspondence between the terminal 42 and the session control server 22, and the session control server 23 that has transmitted the request signal with the terminal 42. The correspondence relationship is changed (S107).

  Further, the subscriber data server 1 transmits the subscriber data associated with the terminal 42 to the session control server 23 (S109).

  The session control server 23 stores the subscriber data in the subscriber data storage unit 237 in association with the terminal 42 (S111).

  Therefore, thereafter, the INVITE signal as in step S19 is transmitted to the session control server 23, and the terminal 41 and the terminal 42 make a call via the session control server 21 and the session control server 23 through a similar sequence. Do. At that time, the session control server 21 uses the subscriber data of the terminal 41, and the session control server 23 uses the subscriber data of the terminal 42.

  Here, the flow of processing related to steps S33 to S39 will be described.

  As shown in FIG. 6, even though the signal receiving unit 231 does not transmit a request signal (for example, INVITE signal) from the session control server 23 to the transfer device, a response signal (for example, a 200 OK signal) is transmitted from the transfer device. (S201), the inquiry unit 232 inquires of the subscriber data server 1 which session control server should receive the signal from the terminal that is the transmission source of the response signal (S203).

  Next, the notification receiving unit 233 receives from the subscriber data server 1 a correspondence notification indicating which session control server corresponds to the terminal that is the transmission source of the response signal (S205). That is, the notification receiving unit 233 receives a notification indicating a session control server that should receive a signal transmitted from the terminal that is the transmission source of the response signal (S205).

  Next, the determination unit 234 determines whether or not the session control server indicated in the notification is itself, that is, the session control server 23 (S207).

  If the session control server indicated in the notification is not the session control server 23 (S207: NO), the signal transmission unit 235 transmits a response signal to the session control server indicated in the notification (S209), and performs processing. Finish.

  On the other hand, if the session control server indicated in the notification is the session control server 23 (S207: YES), the signal discarding unit 236 discards the response signal and ends the process.

  In the present embodiment, as shown in FIG. 7, when a response signal is received from the transfer device 32 even though the request signal is not transmitted from the session control server 23 to the transfer device 32, FIG. The processing after step S203 is started. However, the present invention is not limited to this. For example, some signal (for example, an error signal) is transmitted even though the request signal is not transmitted from the session control server 23 to the transfer device 33. In the case of receiving from the transfer device 33, the processing after step S203 may be started.

  As described above, according to the destination session control server 23 in the present embodiment, the response signal (200 OK signal) received in step S33 can be transmitted to the source session control server 22 in step S39. Even the terminal 42 can make a call during the transition period.

  That is, for the terminal 42, the transfer device 32 has already changed the setting (S1), while the subscriber data server 1 has not changed the setting yet and the session control server 23 has no subscriber data yet ( Even during the transition period, the terminal 42 can make a call. The same applies to other communication services as well as calls, that is, the communication service can be continued even during the transition period.

  Further, in this embodiment, it is not necessary to perform maintenance work on both servers, such as changing the routing setting for the migration source server and setting the flag for the migration destination server. Therefore, only one side is implemented, and as a result, there is no inconvenience that the routing is wrong.

  Further, since the maintenance work is only the work for the transfer device as in step S1, even if there are a large number of terminals to be migrated, the maintenance operation can be reduced.

  A technique using the above flag will be described with reference to FIG.

  The transfer destination server in the comparative example corresponding to the session control server 23 supports a flag indicating that the transfer target terminal in the comparative example corresponding to the terminal 42 is the transfer target in order to continue the communication service. For a terminal that is not a transfer target, a flag indicating that it is not a transfer target is stored in association with it. Then, the migration destination server determines whether or not it is a migration target based on the flag, and if it is the migration target, transmits a signal to the migration source server as in steps S39 and S209 of the present embodiment. That is, in the technique of the comparative example, determination by a flag is necessary, and there is a possibility of signal delay.

  On the other hand, in the session control server 23 of the present embodiment, determination by a flag is not necessary. That is, for the terminal to be migrated (in the example, the terminal 42), the correspondence relationship between the terminal 42 and the session control server 22 may be changed to the correspondence relationship between the terminal 42 and the session control server 23 as in step S1. That is, no signal delay is caused by flag determination performed regardless of whether or not it is a transition target, and as a result, processing between terminals that are not the transition target is not affected.

  As described above, the session control server 23 determines the state that the transfer source session control server 22 should receive the signal from the terminal 42 via the transfer device 32, and the signal from the terminal 42 via the transfer device 32. It is a session control server used as a session control server of a transfer destination when shifting to a state to be received by the session control server.

  When the transfer device 32 stores the correspondence relationship between the terminal 42 and the migration source session control server 22, the transfer device 32 transmits a signal from the terminal 42 to the migration source session control server 22, and the correspondence relationship is the same as that of the terminal 42. After changing to the correspondence relationship of the transfer destination session control server 23, a signal from the terminal 42 is transmitted to the transfer destination session control server 23.

  Further, the subscriber data server 1 stores the correspondence relationship between the terminal 42 and the transfer source session control server 22, and the correspondence relationship is transferred to the terminal 42 and the transfer destination session at a later time than the change in the transfer device 32. The correspondence relationship of the control server 23 is changed.

  Then, the session control server 23 receives a response signal to the request signal from the transfer device 32 (S33, S201), and the signal reception unit 231 does not transmit the request signal to the transfer device 32. Regardless, if a response signal to the request signal is received from the transfer device 32 (S33, S201), the subscriber data server 1 is inquired which session control server should receive the signal transmitted from the terminal 42 (S35). , S203) Receive a notification indicating the session control server 22 that should receive the signal transmitted from the terminal 42 from the inquiry unit 232 and the subscriber data server 1 (S37, S205). It is determined whether or not the indicated session control server 22 is itself (S207). If the session control server 22 shown in FIG. 4 is not itself (S207: NO), a response signal is transmitted to the session control server 22 indicated in the notification (S39, S209), and the session indicated in the notification If the control server is itself (S207: YES), the control server includes a signal discarding unit 236 that discards the response signal (S211).

  Therefore, the determination by the flag as in the comparative example is unnecessary, and as a result, the service such as the call can be continued even during the transition, and the processing between the terminals that are not the transition target is not affected. can do.

  In the present embodiment, the terminal 42 is the transfer target, but the transfer target is not limited to the terminal 42. Further, although the transfer source is the session control server 22, the transfer source is not limited to the session control server 22. Further, although the migration destination is the session control server 23, the migration destination is not limited to the session control server 23. The migration destination session control server may be provided with the same functional blocks as in FIG.

  In the present embodiment, after changing the correspondence between the terminal and the session control server in the subscriber data server 1, the session control server 23 acquires and stores the subscriber data. However, the subscriber data is acquired in advance, You may save it.

  In this embodiment, an example has been described in which the request signal is an INVITE signal and the response signal is a 200 OK signal. However, the request signal may be transmitted and received in the service, and the response signal may be the response signal. Good.

DESCRIPTION OF SYMBOLS 1 ... Subscriber data server 21, 22, 23 ... Session control server 31, 32, 33 ... Transfer apparatus 41, 42, 43 ... Terminal 231 ... Signal receiving part 232 ... Inquiry part 233 ... Notification receiving part 234 ... Determination part 235 ... Signal transmission unit 236 ... Signal discard unit 237 ... Subscriber data storage unit

Claims (2)

When the signal from the terminal is to be received by the transfer source session control server via the transfer device when the signal from the terminal is transferred to the state to be received by the transfer destination session control server via the transfer device A session control server used as a session control server of the migration destination,
The transfer device is
When the correspondence relationship between the terminal and the migration source session control server is stored, a signal from the terminal is transmitted to the migration source session control server, and the correspondence relationship is determined between the terminal and the migration destination session. After being changed to the correspondence relationship of the control server, the signal from the terminal is transmitted to the session control server of the migration destination,
The session control server is connected to a subscriber data server via a communication line;
The subscriber data server is
The correspondence relationship between the terminal and the migration source session control server is stored, and the correspondence relationship is changed to the correspondence relationship between the terminal and the migration destination session control server at a time later than the change in the transfer device. And
The session control server
A signal receiving unit that receives a response signal to the request signal from the transfer device;
A signal transmitted from the terminal to the subscriber data server if the signal receiving unit receives a response signal to the request signal from the transfer device even though the request signal is not transmitted to the transfer device. A query unit that inquires which session control server should receive
A notification receiving unit for receiving a notification indicating a session control server to receive a signal transmitted from the terminal from the subscriber data server;
A determination unit that determines whether or not the session control server indicated in the notification is itself;
If the session control server indicated in the notification is not itself, a signal transmission unit that transmits the response signal to the session control server indicated in the notification;
A session control server comprising: a signal discard unit that discards the response signal if the session control server indicated in the notification is itself. When the signal from the terminal is to be received by the transfer source session control server via the transfer device when the signal from the terminal is transferred to the state to be received by the transfer destination session control server via the transfer device The operation method of the session control server used as the destination session control server,
The transfer device is
When the correspondence relationship between the terminal and the migration source session control server is stored, a signal from the terminal is transmitted to the migration source session control server, and the correspondence relationship is determined between the terminal and the migration destination session. After being changed to the correspondence relationship of the control server, the signal from the terminal is transmitted to the session control server of the migration destination,
The session control server is connected to a subscriber data server via a communication line;
The subscriber data server is
The correspondence relationship between the terminal and the migration source session control server is stored, and the correspondence relationship is changed to the correspondence relationship between the terminal and the migration destination session control server at a time later than the change in the transfer device. And
The operation method is as follows:
A signal receiving unit of the session control server receives a response signal to the request signal from the transfer device;
If the inquiry unit of the session control server receives a response signal to the request signal from the transfer device even though the signal reception unit has not transmitted the request signal to the transfer device, the subscriber data server To which session control server should receive the signal transmitted from the terminal,
The notification receiving unit of the session control server receives a notification indicating the session control server to receive a signal transmitted from the terminal from the subscriber data server,
The determination unit of the session control server determines whether or not the session control server indicated in the notification is itself,
If the session control server signal transmission unit is not the session control server indicated in the notification, the signal transmission unit transmits the response signal to the session control server indicated in the notification,
The session control server operating method, wherein the signal discard unit of the session control server discards the response signal if the session control server indicated by the notification is itself.

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