JP5056076B2 - Session control server and subscriber cache control method - Google Patents

Description

The present invention relates to a session control server and a subscriber cache control method in an IP telephone system.

  An SIP proxy server (Session Initiation Protocol Proxy Server) that controls establishment of a session for making a call between IP telephone terminals via an IP (Internet Protocol) network receives subscriber information including login information and telephone number of the IP telephone terminal. For example, when the calling IP telephone terminal dials the telephone number of the called IP telephone terminal, an Invite message is transmitted to the SIP proxy server. The SIP proxy server refers to the subscriber information, transmits an Invite message to the destination IP phone terminal side, and transmits 200 OK to the SIP proxy server in response to the response from the destination IP phone terminal. 200 OK is transmitted, the originating IP telephone terminal transmits ACK, and the SIP proxy server transmits ACK to the destination IP telephone terminal. Thereby, a session between the originating IP telephone terminal and the destination IP telephone terminal is established.

  Various configurations have already been proposed for the SIP proxy server that controls session establishment between the IP telephone terminals described above (see, for example, Patent Document 1 or Patent Document 2). The subscriber database for registering subscriber information is generally configured by a hard disk device. However, a semiconductor memory having a remarkably fast access speed is provided as a subscriber cache, and the subscriber information registered in the subscriber database is stored. A configuration is generally used in which the data is also stored in the subscriber cache, and the session is established by accessing the subscriber cache in accordance with the Invite message from the calling IP telephone terminal side.

  For example, as shown in the outline of the conventional example shown in FIG. 14, the SIP proxy server 101 has a configuration including a subscriber database 102 and a subscriber cache 103, and a subscriber is registered by a subscriber registration command from the maintenance terminal 104. The information is registered in the subscriber database 102, and the subscriber information is read from the subscriber database 102 by a Register command from the IP telephone terminal 105 and stored in the subscriber cache 103. Similarly, the subscriber information of the IP telephone terminal 106 is also registered in the subscriber database 102, and the subscriber information is stored in the subscriber cache 103 by a Register command. In this state, when the IP telephone terminal 106 dials the telephone number of the IP telephone terminal 105, an Invite message is sent to the SIP proxy server 101, and the SIP proxy server 101 is stored in the subscriber cache 103. The called IP telephone terminal 105 is called according to the subscriber information and responds to the call, thereby establishing a session. The subscriber information registered in the subscriber database 102 is also stored in the subscriber cache 103 according to login, and finally stored in the subscriber cache 103 and the number of subscribers X registered in the subscriber database 102. The same number of subscribers X and the same information content.

Also, a memory serving as a subscriber cache is provided in the SIP proxy server, subscriber information is registered in an external database, and only the necessary subscriber information from the external database is stored in the memory of the SIP proxy server by a Register command from the IP telephone terminal. There is also known a means for storing and sending an Invite message to the destination IP telephone terminal based on the subscriber information stored in the memory by the SIP proxy server by calling (Invite) from the calling IP telephone terminal. In this case, all of the subscriber information registered in the external database is finally stored in the subscriber cache by the Register command from all IP telephone terminals (see, for example, Patent Document 3).
JP 2004-523174 A JP 2006-325038 A JP 2006-244099 A

  In the conventional example in which the SIP proxy server is provided with a subscriber cache to increase the processing speed, the subscriber information registered in the subscriber database provided inside or outside is stored in the subscriber cache. As shown in FIG. 14, the number of subscribers in the subscriber cache and the subscriber database is the same. Therefore, a SIP proxy server that provides a session establishment service to a large number of subscribers requires a subscriber cache having substantially the same capacity as well as a large subscriber database corresponding to the number of subscribers. In other words, there is a problem that the system cost becomes very high.

  An object of the present invention is to solve the above-described problems, and to effectively use a subscriber cache having a small capacity.

Session control server of the present invention, the subscriber information from the subscribers database, contains a pointer for indicating a write area to the subscriber cache, and subscriber login status corresponding to each region of the subscriber cache, logout status A reuse candidate table for managing whether the call is in a call state , and the reuse candidate table includes a logout queue indicating the subscriber cache area corresponding to the subscriber in the logout state, and the login look contains a login queue indicating the subscriber cache area corresponding to the subscriber who has become a subscriber and calling state in which the state, the control processing unit, free space of the subscriber cache for login request If no, if there is the logout queue, in the area indicated by the logout queue, addition of the login request The user information, in the absence of the subscriber database and overwriting processing is read from the free space of the subscriber cache, if there is no said logout queue, in the area indicated by the log queue, the subscriber information of the login request, Control means for reading from the subscriber database and overwriting is provided.

  In addition, the least frequently used subscriber cache area is indicated by the pointer at the top position of the login queue in the reuse candidate table, and the login queue pointer corresponding to the re-login request is queued at the end of the login queue. So that the control processing unit performs control processing.

  In addition, a control process is performed so that the pointer corresponding to the logout subscriber in the logout queue of the reuse candidate table is linked to the tail, and a new address is added to the area of the subscriber cache indicated by the pointer at the head position that is not frequently used. The control processing unit is configured to perform a control process so that new subscriber information is overwritten.

  Further, the subscriber cache control method of the present invention manages the state corresponding to the area of the subscriber cache in the SIP proxy server including the subscriber database, the subscriber cache and the control processing unit, and indicates the area. A reuse candidate table having a login queue including a pointer and a logout queue is provided. At the time of login, the reuse candidate table is referred to, and an area of the subscriber cache indicated by the pointer indicating low use frequency is selected. This includes a control processing step of writing the subscriber information of a new login request in the area of the subscriber cache and linking the logout queue pointer indicating the area to the end indicating that the frequency of use is high.

  Also, it is determined whether or not subscriber information corresponding to the subscriber at the time of login exists in the subscriber cache, and if it exists, a pointer indicating the area of the subscriber cache is set at the end of the login queue of the reuse candidate table. If there is no logout area of the subscriber cache in the logout queue, the logout queue of the reuse candidate table is searched and the logout queue of the reuse candidate table is searched. The subscriber cache area indicated by the pointer linked to the head of the login queue is overwritten with the login subscriber information, and the pointer indicating this subscriber cache area is linked to the end of the reuse candidate table. Process.

  A reuse candidate that includes a subscriber database in which subscriber information is registered, a subscriber cache that holds only subscriber information corresponding to usage frequency, and a reuse candidate table for effectively using the subscriber cache. The subscriber database is controlled by overwriting the subscriber information of the login request with respect to the subscriber information storage area of the subscriber cache indicated by the pointer of the less frequently used area of the subscriber cache according to the table. Therefore, the session establishment control process can be performed with a subscriber cache having a smaller storage area than that of the SIP cache server. Therefore, the cost of the SIP proxy server can be reduced.

Session control server of the present invention, referring to FIG. 1, a session control server includes a subscriber database 2 and the subscriber cache 3 and control unit 8, the subscriber information from the subscriber database 2, the subscriber A reuse candidate table 7 that includes pointers that indicate areas to be written to the subscriber cache 3 and that manages whether the subscriber corresponding to each area of the subscriber cache 3 is in a login state, a logout state, or a call state. provided, the reuse candidate table 7, and out queue 7b indicating the subscriber cache area corresponding to the subscriber a logout state, the subscriber a state in subscriber and passing story of a login status look contains a login queue 7a indicating the subscriber cache area corresponding, control processor 8, the subscription respect login request When there is no free space in the cache and there is the logout queue, the subscriber information of the login request is read from the subscriber database and overwritten in the area indicated by the logout queue, and the free space in the subscriber cache If no, the absence the logout queue, in the area indicated by the log queue, the subscriber information of the login request, and a control means for overwriting process reads from the subscriber database 2.

  The subscriber cache control method of the present invention manages the state corresponding to the area of the subscriber cache 3 in the SIP proxy server 1 including the subscriber database 2, the subscriber cache 3, and the control processing unit 8. A reuse candidate table 7 having a login queue 7a and a logout queue 7b including pointers indicating areas is provided, and at the time of login, the reuse candidate table 7 is referred to and indicated by a pointer indicating low use frequency The area of the subscriber cache 3 is selected, the subscriber information of a new login request is written in the area of the subscriber cache 3, and the pointer of the logout queue 7b indicating the area is used frequently. It includes a control process to be linked to.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, where 1 is a SIP proxy server, 2 is a subscriber database, 3 is a subscriber cache, 4 is a maintenance terminal, 5 and 6 are IP telephone terminals, and 7 is a re-transmission. A use candidate table, 7a is a login queue, 7b is a logout queue, and 8 is a control processing unit. Note that the control means and network configuration for transmission and reception between the maintenance terminal 4 and the IP telephone terminals 5 and 6 are not shown, but various known configurations can be applied. The control processing unit 8 controls each unit and includes processing means such as access control means for the subscriber database 2 and the subscriber cache 3 and means for performing session establishment processing. Can be configured.

  The reuse candidate table 7 includes a login queue 7a and a logout queue 7b, and can be formed by a partial area of the subscriber cache 3 or a memory separate from the subscriber cache 3. Further, when the subscriber database 2 has a storage capacity capable of registering all the nX number of subscriber information, the subscriber cache 3 has only the X number of subscriber information that is frequently used among the nX number of all subscriber information. Is the storage capacity to hold In this case, whether or not the subscriber is frequently used is managed by the reuse candidate table 7, and the control processing unit 8 controls the update of the reuse candidate table 7 together with the update from the subscriber database 2 to the subscriber cache 3. The storage capacity of the subscriber cache 3 is reduced by writing the subscriber information and overwriting the new subscriber information in the area of the subscriber cache 3 corresponding to the less frequently used subscriber by performing a new login. Even so, the session establishment process can be executed at high speed. Accordingly, it is possible to reduce the cost of the SIP proxy server 1 by setting the subscriber cache 3 that can be accessed at high speed and having a small capacity compared to the storage capacity of the subscriber database 2.

  FIG. 2 is a schematic explanatory diagram of the subscriber cache and the reuse candidate table. The subscriber cache 3 includes a free (1) area corresponding to the initial state and a login cache storing subscriber information by login. In the initial state of the subscriber cache 3, the entire area is an empty area. Accordingly, subscriber information by new login is stored by selecting and selecting free areas sequentially, so that each area of the subscriber cache 3 transitions from the free area state to the login cache state and makes a call by establishing a session. In the state to be performed, the state transits to the in-call cache state, and transitions to the logout cache state by logout upon termination of the call.

  The reuse candidate table 7 manages the state of each area of the subscriber cache 3 and has a configuration in which the area is indicated by a pointer. The reuse candidate table 7 includes a logout queue 7b and a login queue 7a. Is linked at the end. In this case, the upper part of the figure is a pointer that indicates an area where the subscriber cache used in the past is less frequently used. Therefore, when there is no free space in the subscriber cache 3 due to the login request, the area of the subscriber cache 3 that is less frequently used linked to the head (upper part) of the logout queue 7b is reused and the subscriber information is overwritten. . The arrow (2) indicates the order of the logout cache 7b from the oldest to the newest in that case.

  The login queue 7a is composed of pointers to the login cache state area and the in-call cache state area of the subscriber cache 3, and is linked at the end at the time of login. , Transition to the login cache state at the end of the talk, and linked to the tail of the login queue 7a. In this case, the arrow (3) indicates the order from the oldest to the newest, indicating that there is no free area in the subscriber cache 3 and that no usable cache area exists even if the logout queue 7b is referenced. The cache area linked to the head of the login queue 7a is reused, and the newly logged-in subscriber information is overwritten. As described above, by using the reuse candidate table 7, even when the area of the subscriber cache 3 is smaller than the area of the subscriber database 2, the subscriber cache 3 can be effectively used.

  FIG. 3 shows a main configuration of the subscriber cache and the reuse candidate table, and the subscriber cache 3 is configured by a cache # 1 (Cache # 1) to a cache FF (Cache FF). , SIP-URI, Contact, and login Login, logout Logout, and talking Talking indicating the status of the area of the subscriber cache 3, for example, Cache # 1 is indicated by adding an underline to Login. The login state, Cache # 2 represents the logout state as indicated by adding an underline to Logout. These are for convenience of explanation.

  The reuse candidate table 7 includes a logout queue 7b and a login queue 7a, and forms a link between the head Head and tail tail, respectively. The logout queue 7b includes Logout # 1 to LogoutFF, and each head Head Order Forward #, order Backward # from the tail end, and Cache-oid indicating the area position of the subscriber cache 3, and the login queue 7a also includes Login # 1 to LoginFF. In this example, the contents include the order Forward # from the first head, the order Backward # from the tail of the tail, and the cache-oid indicating the area position of the subscriber cache 3. The dotted line arrow indicates the area Cache # 1 in the login state of the subscriber cache 3 by the Login # 1 Cache-oid of the login queue 7a, and the area Cache # 2 in the logout state of the subscriber cache 3 indicates the logout queue. This is an example in the case of 7b Logout # 2 Cache-oid.

  FIGS. 4A and 4B are explanatory diagrams of main contents of the subscriber cache and the reuse candidate table at the time of login. FIG. 4A shows a change state of contents at the time of re-login and FIG. The subscriber cache and the reuse candidate table transition from the upper state to the lower state by the login process. That is, when logging in for the first time, the top area of the subscriber cache corresponding to no contact indicated by, for example, a bold line in the logout queue of the reuse candidate table is set as the login cache, and no logout queue contact in the reuse candidate table is set as the login queue. Link as shown in the bold line frame at the end of the contact. Also, at the time of re-login shown in FIG. 4B, for example, the contact indicated by the upper thick line frame in the login queue of the reuse candidate table is relinked at the end as shown by the lower thick line frame. Therefore, the pointer indicating the area of the subscriber cache indicated as having the last contact in the login queue of the reuse candidate table indicates the latest access area of the subscriber cache.

  FIG. 5 shows a flowchart at the time of login. The SIP proxy server checks whether there is cache data of the login subscriber by logging in (Register reception) with reference to the logout queue in the most used candidate table (A1). Then, it is determined whether or not it exists in the subscriber cache (A2). If it does not exist, a request for newly capturing the subscriber cache area is made (A3). Then, it is determined whether or not capture is possible (A4). If capture is possible, the setting of Contact, Expire, and writing to the subscriber CH (subscriber cache) are performed (A5), and the area of the subscriber cache is indicated. The cache information including the pointer to be queued is queued at the tail end of the login queue of the reuse candidate table (A6), and a 200 OK response indicating successful request is sent (A7).

  If it is determined in step (A4) that it cannot be captured, the logout queue of the reuse candidate table is searched. If the logout queue cannot be searched, the login queue is searched (A8). (A9), and if it can be captured, the subscriber information is overwritten in the captured subscriber cache area. In this case, the Contact and Expire settings are also written to the subscriber cache (A10). Then, the cache information is queued at the tail end of the login queue of the reuse candidate table (A11), and a 200 OK response is sent (A12). In step (A9), if it cannot be captured, a 503 NG response indicating that the service cannot be used is sent (A13).

  If it is determined in step (A2) that the cache is present, “Contact” and “Expire” are set and written to the subscriber cache (A14), and the corresponding cache information is queued at the end of the login queue of the reuse candidate table. (A15), and a 200 OK response is transmitted (A16). If writing including overwriting of subscriber information to the subscriber cache is successful, information including a pointer indicating the area of the subscriber cache is linked to the tail of the login queue of the reuse candidate table indicating the latest.

  FIG. 6 is a diagram for explaining the main contents of the subscriber cache and the reuse candidate table at the start of the call. When the call is started, there is no subscriber target cache (A), and there is a cache ( B), and when there is no cache (A), the first cache area of the logout queue of the reuse candidate table (or the login queue if there is no logout queue) is recaptured and the corresponding subscriber information is sent to the login subscriber. Overwrite and link at the end of the reuse candidate table (login queue) as shown by the bold frame. In response to a call, the state of the corresponding area of the subscriber cache is changed from logout to during a call. That is, as shown on the lower side of the reuse candidate table shown in the upper part of the reuse candidate table shown in FIG. 6A, the subscriber cache is a call cache and the reuse candidate table is shown in the lower part. At the end of the login queue of, as indicated by the thick line frame, is queued as contacted.

  If there is a cache (B), the state of the corresponding area of the subscriber cache is changed from the state of the login cache to the state of the busy cache, and the position of the login queue in the reuse candidate table is not updated. For example, the position with the contact in the thick line frame of the login queue of the reuse candidate table whose correspondence is indicated by the dotted line arrow with the login cache of the subscriber cache shown on the upper side of FIG. 6B is as it is shown on the lower side. And the state of the area of the subscriber cache indicated by the dotted arrow corresponding thereto is transitioned as shown as a busy-call cache.

  FIG. 7 is a flowchart at the start of a call. When Invite reception is performed, it is checked whether or not the calling or called subscriber cache data exists (B1), and it is determined whether or not it exists in the subscriber cache (B2). If it exists, the subscriber information held in the subscriber cache is read to check information such as the blocked status and service contract status (B3), and it is determined whether or not the check is OK (B4). If the check is OK, a 200 OK response indicating successful request is sent (B5), and the state of the corresponding area of the subscriber cache is set to be in a call (B6).

  If it is determined in step (B2) that the subscriber cache does not exist, a request is made to capture a new subscriber cache area (B7), whether or not the capture is OK (B8). Overwrites the subscriber information in the corresponding area of the subscriber cache, checks the status (B9), determines whether logout or Expire has been completed (B10), and if none of them, goes to step (B3) If any of the cache information has been transferred or has been completed, the corresponding cache information is queued at the tail end of the login queue (in) of the reuse candidate table (B11), indicating that processing in this case is prohibited. A 403 response is sent (B12). If it is determined that the check is not OK in step (B4), a 4xx NG response indicating a request error response or a 5xx NG response indicating a server error response is sent (B13), and the corresponding cache information is logged into the reuse candidate table. Queue to the end of the queue (in) (B14). If it is determined in step (B8) that capture is impossible, the candidate cache is searched in the order of logout queue (out) → login queue (in) in the reuse candidate table (B15), and whether or not capture is OK. If it is determined that the acquisition is OK, the process proceeds to step (B9). If the acquisition is impossible, a 503 response indicating that the service cannot be used is transmitted (B16).

  FIG. 8 is a diagram for explaining the main contents of the subscriber cache and the reuse candidate table at the end of the call. The call cache in the subscriber cache shown on the upper side and the reuse candidate table showing a correspondence relationship with dotted arrows When there is a contact indicated by the bold line frame of the login queue, as shown on the lower side by the end of the call, the state of the in-call cache of the subscriber cache is updated to the state of the login cache, and the login queue of the reuse candidate table is Cue at the end, as shown by the bold border contact. If it is from the beginning to the end, there is no change. Therefore, the subscriber cache area indicated by the login queue pointer indicated by the bold frame indicates the latest access area.

  FIG. 9 is a flowchart at the end of the call, and checks whether there is a dialog corresponding to the Bye request (C1) by ending the call (Bee reception), determines whether there is a dialog (C2), and exists. In this case, the end state is written in the subscriber cache (C3), a 200 OK response is sent (C4), and the corresponding cache information is queued at the end of the login queue (in) of the reuse candidate table. If there is no dialog in step (C2), the received Bye request is discarded (C6).

  FIG. 10 is a diagram for explaining the main contents of the subscriber cache and the reuse candidate table at the time of logout. The reuse cache table of the reuse cache indicates the correspondence with the login cache area of the subscriber cache shown on the upper side and the dotted arrow. When there is a contact in the thick line frame of the login queue, by logging out, the login cache state of the subscriber cache is changed to the logout cache state as shown below, and the logout queue of the reuse candidate table corresponding to this is changed. At the end of the queue as shown without a thick border contact.

  FIG. 11 is a flowchart at the time of logout. By logout (De-Register reception), it is checked whether the logout subscriber's cache data exists (D1), and whether there is information corresponding to the logout subscriber in the subscriber cache. (D2), if it does not exist, request a new acquisition of the subscriber cache area (D3), determine whether the acquisition is OK (D4), and in the case of acquisition OK, in the subscriber cache In the above-mentioned figure, the subscriber information is set, the Contact (= NULL) setting, the Expire time (= 0) setting (see the subscriber cache 3 in FIG. 3) (D5), and the pointer indicating the area of the corresponding cache information. As shown in FIG. 10, the presence of contact is queued at the end of the logout queue (out) of the reuse candidate table (D ), And it sends a 200 OK response (D7).

  In step (D4), if the capture is not OK, search is made in the order of the logout queue (out) of the reuse candidate table → the login queue (in) of the reuse candidate table (D8), and whether or not the capture is OK. If it is determined that the acquisition is OK, the subscriber information of the corresponding cache data is overwritten with the new login subscriber (D10), and the corresponding cache information is queued at the end of the logout queue (out) of the reuse candidate table. (D12). In step (D9), if the acquisition is not OK, 503 NG indicating that it cannot be used is sent (D16).

  If the cache exists in step (D2), the subscriber information is set in the cache, the contact (= NULL) is set, and the expire time (= 0) is set (step 5). 3) (D13), the corresponding cache information is queued at the end of the logout queue (out) of the reuse candidate table (D14), and a 200 OK response is transmitted (D15).

  FIG. 12 is a diagram for explaining the main contents of the subscriber cache and the reuse candidate table when the subscriber is deleted. The subscriber cache corresponding to the presence of the contact indicated by the bold line frame in the login queue of the reuse candidate table shown on the upper side is shown in FIG. The login cache is released as an empty cache such as the subscriber cache shown below, and the login queue link in the reuse candidate table is also deleted as indicated by a cross.

  FIG. 13 is a flowchart for deleting a subscriber. According to the delete subscriber command, the subscriber database is searched for the presence of the target subscriber (E1), and whether the search result is OK is determined (E2). In the case of OK, the cache control (control processing unit 8 in FIG. 1) that controls the subscriber cache is inquired about the existence of the cache data of the subscriber (E3), and it is determined whether or not the cache data exists in the subscriber cache. (E4) If it exists, it is determined whether or not a call exists (E5). If it exists, the subscriber deletion command is set to NG (E6). If it is determined in step (E2) that the search result is not OK, there is no corresponding subscriber, so the subscriber deletion command is NG (E7). In step (E4), if the determination result does not exist in the subscriber cache, the subscriber information is deleted from the subscriber database (E8), and the subscriber deletion command is OK (E9).

  If there is a call in step (E5), the subscriber cache information is deleted (E10), and the login queue (in) and logout queue (out) in the reuse candidate table are searched (E11). (E12), if not, the subscriber information is deleted from the subscriber database (E13), the subscriber deletion command is OK (E15), and in step (E12) If the determination result exists, the cache information is deleted from the corresponding table queue (E14), and the process proceeds to step (E13).

  Further, in FIG. 1, the subscriber cache 3 is periodically checked at regular intervals using the subscriber database 2 as an original. As a result of this collation, the subscriber information existing only in the subscriber cache 3 and the reuse candidate table 7 is deleted. As a result, the area of the subscriber cache 3 can be effectively used. If there is a mismatch, overwriting correction can be performed with the subscriber information registered in the subscriber database 2. Thereby, the consistency of the subscriber information in the subscriber database 2 and the subscriber information in the subscriber cache can be ensured, and the reliability of session establishment by the SIP proxy server 1 can be maintained.

  Also, periodic garbage processing is performed on the subscriber cache 3. That is, in order to release the area of the subscriber cache 3 that is no longer necessary, the periodic garbage processing is performed in the same manner as the garbage collection in which the processing program is temporarily stored in the memory area and the memory area is released upon completion of the program processing. Execute to release the cache contents in the logout state on the subscriber cache. As a result, the logout queue can be deleted, the capacity of the reuse candidate table 7 can be reduced, and a free cache area is formed in the subscriber cache 3 to speed up the new login process. It is also possible.

(Supplementary Note 1) In a SIP proxy server including a subscriber database, a subscriber cache, and a control processing unit, a pointer that indicates an area in which subscriber information from the subscriber database is written to the subscriber cache; A reuse candidate table for managing a login state, a logout state, and a call state in each area of the subscriber cache is provided. The reuse candidate table includes a logout queue for managing the logout state, the login state, and a call state. A login queue that manages a state, and the control processing unit refers to the reuse candidate table for a new login request, and the subscriber cache is used in an area corresponding to a low frequency of use of the subscriber cache Then, the subscriber information of the new login request is read from the subscriber database and overwritten. SIP proxy server, characterized in that it comprises a control means.
(Supplementary Note 2) The area of the subscriber cache that is least frequently used is indicated by the pointer at the head position of the login queue in the reuse candidate table, and the pointer of the login queue corresponding to the re-login request is set in the login queue. The SIP proxy server according to supplementary note 1, comprising a configuration in which control processing is performed by the control processing unit so as to queue at the end.
(Supplementary Note 3) The area of the subscriber cache indicated by the pointer at the head position that is used less frequently, by performing control processing so that the pointer corresponding to the logout subscriber in the logout queue of the reuse candidate table is linked to the tail. The SIP proxy server according to supplementary note 1, further comprising a configuration in which control processing is performed by the control processing unit so as to overwrite new subscriber information.

(Additional remark 4) It has the structure which performs the control process by the said control process part so that the pointer of the said log-in queue corresponding to the end-call subscriber of the said reuse candidate table may be linked with the last used frequently. The SIP proxy server according to appendix 1.
(Supplementary Note 5) The control processing unit includes means for periodically correcting and deleting the subscriber cache by comparing the subscriber information with the subscriber information in the subscriber database. The SIP proxy server according to 1.

(Supplementary Note 6) In a subscriber cache control method of a SIP proxy server including a subscriber database, a subscriber cache, and a control processing unit, manages the state corresponding to the area of the subscriber cache and indicates the area A reuse candidate table having a login queue including a pointer and a logout queue, and refers to the reuse candidate table at the time of login, and selects an area of the subscriber cache indicated by the pointer indicating low usage frequency Including a control processing step of writing subscriber information of a new login request in the area of the subscriber cache and linking a pointer of the logout queue indicating the area to the tail indicating high use frequency. A subscriber cache control method.
(Supplementary note 7) It is determined whether or not subscriber information corresponding to the subscriber at the time of login exists in the subscriber cache, and if it exists, a pointer indicating the area of the subscriber cache is used as the reuse candidate table. If there is no logout area of the subscriber cache in the logout queue, the logout queue of the reuse candidate table is searched. A login queue is searched, the subscriber cache area indicated by the pointer linked to the head of the login queue is overwritten with the login subscriber information, and the pointer indicating the subscriber cache area is set to the pointer. The subscriber cache according to appendix 6, including a process of linking to the last part of the reuse candidate table Control method.

(Supplementary note 8) The pointer of the logout queue of the reuse candidate table corresponding to the logout subscriber is linked at the end, and a new subscription is added to the area of the subscriber cache indicated by the pointer at the head position with low usage frequency. The subscriber cache control method according to claim 6, further comprising a step of overwriting subscriber information.
(Supplementary note 9) The subscriber cache control method according to supplementary note 6, including a step of linking a pointer of the login queue of the reuse candidate table corresponding to the end-call subscriber to the end.
(Supplementary Note 10) The subscriber information in the subscriber cache is periodically checked with the subscriber information registered in the subscriber database, the subscriber information existing only in the subscriber cache is deleted, and the verification mismatched subscribers are deleted. The subscriber cache control method according to appendix 6, wherein the information includes a correcting process.

It is explanatory drawing of Example 1 of this invention. It is outline | summary explanatory drawing of the subscriber cache and reuse candidate table of Example 1 of this invention. It is principal part content explanatory drawing of the subscriber cache and reuse candidate table of Example 1 of this invention. It is explanatory drawing of the subscriber cache at the time of login of Example 1 of this invention, and a reuse candidate table. It is a flowchart at the time of login of Example 1 of this invention. It is principal part content explanatory drawing of the subscriber cache at the time of the telephone call start of Example 1 of this invention, and a reuse candidate table. It is a flowchart at the time of the telephone call start of Example 1 of this invention. It is principal part content explanatory drawing of the subscriber cache at the time of the telephone call end of Example 1 of this invention and a reuse candidate table. It is a flowchart at the time of the telephone call end of Example 1 of this invention. It is principal part content explanatory drawing of the subscriber cache at the time of logout of Example 1 of this invention, and a reuse candidate table. It is a flowchart at the time of logout of Example 1 of this invention. It is principal part content explanatory drawing of the subscriber cache at the time of subscriber deletion of Example 1 of this invention, and a reuse candidate table. It is a flowchart at the time of subscriber deletion of Example 1 of this invention. It is explanatory drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 SIP proxy server 2 Subscriber database 3 Subscriber cache 4 Maintenance terminal 5,6 IP telephone terminal 7 Reuse candidate table 7a Login queue 7b Logout queue 8 Control processing part

Claims (5)

In a session control server including a subscriber cache and a control processing unit from a subscriber database,
A pointer indicating an area in which subscriber information from the subscriber database is written to the subscriber cache, and a subscriber corresponding to each area of the subscriber cache is in a login state, a logout state, or a call state . A reuse candidate table for managing whether there is a logout queue indicating the subscriber cache area corresponding to the subscriber in the logout state , the subscriber in the login state , and only contains the login queue indicating the subscriber cache area corresponding to the subscriber who has become a busy state,
The control processing unit, in the absence of free space of the subscriber cache against login request, if there is the logout queue, in the area indicated by the logout queue, the subscription subscriber information before Symbol login request When there is no free space in the subscriber cache and there is no logout queue, the subscriber information of the login request is read from the subscriber database in the area indicated by the login queue. A session control server characterized by comprising a control means for performing overwriting processing . The least frequently used subscriber cache area is indicated by the pointer of the login queue head position in the reuse candidate table, and the login queue pointer corresponding to the re-login request is queued at the end of the login queue. The session control server according to claim 1, further comprising a configuration for performing control processing by the control processing unit so as to perform processing. A control process is performed so that the pointer corresponding to the logout subscriber in the logout queue of the reuse candidate table is linked to the tail, and a new area is added to the area of the subscriber cache designated by the pointer at the head position with low usage frequency. The session control server according to claim 1, further comprising a configuration in which control processing is performed by the control processing unit so as to overwrite subscriber information. In a subscriber cache control method of a session control server including a subscriber database, a subscriber cache, and a control processing unit,
A reuse candidate table having a login queue and a logout queue including a pointer indicating the area and managing a state corresponding to the area of the subscriber cache is referred to. The subscriber cache area indicated by the low pointer is selected, the subscriber information of the new login request is written into the subscriber cache area, and the logout queue pointer indicating the area is selected. A subscriber cache control method comprising a control processing step of linking to the tail indicating that the frequency of use is high. It is determined whether the subscriber information corresponding to the subscriber at the time of login exists in the subscriber cache. If there is, the pointer indicating the area of the subscriber cache is set in the login queue of the reuse candidate table. If it does not exist, the logout queue of the reuse candidate table is searched. If the logout area of the subscriber cache does not exist in the logout queue, the login queue of the reuse candidate table is searched. Then, the subscriber cache area indicated by the pointer linked to the head of the login queue is overwritten with the login subscriber information, and the pointer indicating the subscriber cache area is used as the reuse candidate table. subscriber cache according to claim 4, comprising a control process to link to the end Control method.

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