JP4811364B2 - Terminal device, system, terminal control method, and terminal program - Google Patents

Description

  The present invention relates to a terminal device, a system, a terminal control method, and a terminal program.

  Patent Document 1 discloses a system in which a client that communicates with one of a plurality of servers communicates with a server selected by a certain server. In this technology, the client is the main body and does not determine the destination server.

  Patent Document 2 discloses a system in which a server (reception destination) receives a notification code of a server (transmission source) through a relay computer. This technology is mainly based on a server (reception destination) and does not select a communication destination relay computer.

Japanese Patent Laid-Open No. 9-106381 JP-A-8-16502

  The techniques of Patent Documents 1 and 2 have a problem that a communication destination server of a terminal must be selected mainly by a server other than the terminal, either individually or in combination. An object of the present invention is to provide a terminal device, a system, a terminal control method, and a terminal program for solving this problem.

  The terminal device according to an example of the present invention includes a plurality of first servers based on first information acquired from a connection destination list stored in a storage area, a terminal AP, and a plurality of connected first servers. Each state information is memorize | stored in the said connecting point list, based on the state information of said several 1st server, one is selected from these several 1st servers, Between the said selected 1st server and said terminal AP The terminal program which performs communication connection of is provided.

  The terminal control method according to an example of the present invention includes an acquisition process in which a computer acquires first information from each of a plurality of first servers connected to the computer, and the plurality of first servers based on the first information. And selecting the one of the plurality of first servers based on the storage process of storing the state information of each in the connection destination list stored in the storage area and the state information of the plurality of first servers. 1 has a connection process for performing communication connection between the server and the terminal AP mounted on the computer.

  The terminal program of an example of the present invention includes: an acquisition process for acquiring first information from each of a plurality of first servers connected to the computer; and a plurality of first servers based on the first information. A storage process for storing each state information in a connection destination list stored in a storage area, and a first one selected from the plurality of first servers based on the state information of the plurality of first servers. Connection processing for performing communication connection between the server and the terminal AP installed in the computer is executed.

  According to the present invention, a communication destination server can be selected mainly by a terminal.

The first embodiment (embodiment 1) of the present invention is as follows. A present Example is the store system 10 comprised from the following three-layer structure, as FIG. 1 and FIG. 2 shows.
1) A client PC 1n having a client AP 12 and operated by an operator.
2) AP server 2m including server AP22.
3) A DB server 3p having a DBMS 32 for controlling a business database.

  Here, AP means an application program. The client PC 1n is a computer also called a terminal device. The AP server 2m is also called a second server. DBMS 32 means a database management system. The DB server 3p is also called a second server.

The store system 10 includes a client PC 1n in a store and an AP server 2m and a DB server 3p in a center.
The store does not have a server computer for business processing. The store system 10 may include one or more client PCs 1n, AP servers 2m, and DB servers 3p. The numbers of each need not match. The server AP 22 includes business processing logic. In this embodiment, it is assumed that the client AP 12 is a NET Framework application from the viewpoint of operability. The server AP 22 is an Enterprise JavaBean (registered trademark) (EJB) application from the viewpoints of reusability and reliability. Communication is performed in accordance with CORBA (Common Object Request Broker Architecture) and SOAP (Simple Object Access Protocol) standards.

  In the store system 10, the connection timeout setting value is set so that no process survives in the AP server 2m when the client PC 1n detects a connection error due to timeout. That is, the connection timeout setting value used by the client PC 1n for monitoring the response of the AP server 2m is longer than the connection timeout setting value used by the AP server 2m for monitoring the response of the DB server 3p. For this reason, when an abnormality occurs in the DB server 3p, before the client PC 1n detects a timeout, the AP server 2m detects the abnormality and the related process in the AP server 2m ends abnormally.

  In addition, the Example of this invention is not limited to a store system. The present invention can also be applied to other systems such as a warehouse system and a broadcasting system.

  FIG. 2 shows the detailed configuration of this embodiment. The configuration of the client PC 1n is as follows.

1) Client AP12
This is a part of an application program (AP) that performs business processing of the store system 10. This executes business processing in cooperation with the server AP22 which is an AP on the AP server 2m side.

2) Connection destination determination component CA
This component acquires the identifier of the AP server 2m to be connected from the CL connection destination information holding component CB. If this component receives a response from the CL connection destination information holding component CB that all the AP servers 2m cannot be connected, it stops the connection to the AP server 2m and performs local processing on the client PC 1n alone. Decide to do.

3) CL connection destination information holding component CB
This component manages information of each AP server 2m stored in the CL connection destination list 14.

4) Connection destination switching component CC
This component receives a communication result report with the AP server 2m from the communication component CE and checks it to detect the occurrence of a connection error or timeout. This part will retry when there is a connection error. In addition, this component updates the information in the CL connection destination list 14 via the CL connection destination information holding component CB in accordance with the communication result report.

  In addition, when all the DB servers 3p connected to the specific AP server 2m receive the failure information from the connection teacher death detection component CD, this component uses the CL connection destination information on the AP server 2m as the CL connection destination. Update via the information holding component CB. Even when the connection teacher death detection component CD notifies that the AP server 2m that has been in trouble is returned, this component uses the CL connection destination information holding component CB to send the information in the CL connection destination list 14 related to the AP server 2m. Update with.

5) Connection teacher death detection component CD
This component polls the AP server 2m registered in the CL connection destination list 14 via the communication component CE based on the rules determined by the settings. Polling is performed on the AP status return component AF provided in the AP server 2m, and the connection confirmation and response time confirmation between the client PC 1n and the AP server 2m are performed. Polling also confirms the state of the DB server 3p of the AP server 2m. This component notifies the connection destination switching component CC when the return of the AP server 2m is confirmed by polling. The return of the AP server 2m is detected when the communication with the AP server 2m is successful and the status of the DB server 3p connected to the AP server 2m is normal.

6) Communication parts CE
This part communicates with the AP server 2m and acquires its status information (first information) by data reception or communication time monitoring. Here, the status information acquired from the AP server 2m includes both information obtained by receiving from the AP server 2m and information obtained indirectly when communication with the AP server 2m is over. The AP status 18m of the CL connection destination list 14 is set based on the status information acquired here.

7) CL connection destination list 14
This data is a list of AP servers 2m that can be connected from the client PC 1n, provided for load distribution and smoothing of the switching destination at the time of failure for each client PC 1n. This data is stored in the storage area of the client PC 1n. The client PC 1n selects and connects the AP server 2m to be connected based on the CL connection destination list 14 at the start of business process communication. According to FIG. 3, the CL connection destination list 14 includes an identifier AP_ID 16m of the AP server 2m that is a connection destination candidate, an AP communication address 17m of the AP server 2m, and an AP status 18m indicating the operation state of the AP server 2m. To do. Here, the AP status 18m takes one of a normal state (Active), a high load state (Busy), and a failure state (Dead). The AP status 18m is also called state information of the first server.

8) Local DB15
This is a database used when local processing is performed by the client PC 1n alone.

  The connection destination determination component CA, the CL connection destination information holding component CB, the connection destination switching component CC, the connection teacher death detection component CD, and the communication component CE constitute the client middleware 13. The client middleware 13 only needs to include the functions of the above components, and the functional division is not limited to the division according to the components. The client middleware 13 is also called a terminal program. Further, there may be no local DB 15. FIG. 9 shows the configuration of the client PC 1n taking these conditions into consideration.

  According to FIG. 2, the configuration of the AP server 2m is as follows.

1) Server AP22
This is a part of an application program (AP) that performs business processing of the store system 10. This executes business processing in cooperation with the client AP 12 which is the AP on the client PC 1n side.

2) Connection parts AA
This component provides the server AP 22 with a connection method to the DB server 3p. This component passes a distribution key to the status acquisition component AB, and establishes a connection with the DB server 3p selected based on the distribution key.

3) Status acquisition part AB
This component determines the connection destination priority based on the distribution key, acquires the identifier (DB_ID 26p) of the DB server 3p to be connected from the AP connection destination information holding component AC, and returns it to the connection component AA.

4) AP connection destination information holding component AC
This component manages information of each DB server 3p stored in the AP connection destination list 24.

5) Polling parts AE
This component polls the DB server 3p registered in the AP connection destination list 24. This polling communicates with the DB server 3p and acquires the status information (second information) by receiving or monitoring the communication time. Here, the status information acquired from the DB server 3p includes both information obtained by receiving from the DB server 3p and information obtained indirectly by communication over time to the DB server 3p. The DB status 28p of the AP connection destination list 24 is set based on the status information acquired here.

  Communication performed by polling is performed in a non-blocking mode. This is because polling communication does not delay communication with the DBMS 32. Furthermore, even when a stall occurs during communication with the DBMS 32 or polling by another AP server 2m, this part does not perform unnecessary waiting.

6) AP status return part AF
This component receives polling of the client PC 1n, acquires the DB status 28p from the AP connection destination list 24 via the AP connection destination information holding component AC, and transmits it to the client PC 1n.

7) AP connection destination list 24
This is a list of DB servers 3p that can be connected to the AP server 2m, provided for load distribution and smoothing of the switching destination at the time of failure for each AP server 2m. This data is stored in the storage area of the AP server 2m. The AP server 2m selects and connects the DB server 3p to be connected based on the AP connection destination list 24 at the start of business process communication. According to FIG. 4, the AP connection destination list 24 includes the identifier DB_ID 26p of the DB server 3p that is a candidate for the connection destination, the DB communication address 27p of the DB server 3p, and the DB status 28p indicating the operation state of the DB server 3p. To do. Here, the DB status 28p takes one of a normal state (Active), a high load state (Busy), and a failure state (Dead). The DB status 28p is also called status information of the second server.

  The connection component AA, the status acquisition component AB, the AP connection destination information holding component AC, the polling component AE, and the AP status return component AF constitute the AP server middleware 23. The AP server middleware 23 only needs to include the functions of the respective components, and the function division is not limited to the division according to the components. The AP server middleware 23 is also called a server program.

  According to FIG. 2, the configuration of the DB server 3p is as follows.

1) DBMS32
In response to a request from the server AP 22, management such as database reference update is performed.

2) DB status monitoring component DA
This component monitors the state of the DBMS 32 and notifies the status management component DD of the status when the operation is disabled (Dead), response time delay (Busy) occurs due to overload, or recovery from a failure (Alive). Monitoring is performed by issuing a predetermined SQL (Structured Query Language) statement and checking its return value and response time. This execution example uses the “SELECT 1 FROM DUAL” statement.

3) Status management component DD
This component holds and manages the status information (database status information) of the DBMS 32 notified by the DB status monitoring component DA.

4) Communication standby part DC
This component accepts communication from the AP server 2m in the non-blocking mode. When there is communication from the AP server 2m, this component acquires the database status information from the status management component DD and returns it to the AP server 2m.

  The DB status monitoring part DA, the status management part DD, and the communication standby part DC constitute part of the DB server middleware 33. The DB server middleware 33 only needs to include the functions of the above components, and the function division is not limited to the division according to the components. The DB server middleware 33 may be implemented as a part of a so-called OS.

Next, the operation of the present embodiment will be described with reference to the drawings.
Here, it is assumed that all the AP servers 2m and DB servers 3p are normal at the beginning, and the AP status 18m in the CL connection list 14 and the DB status 28p in the AP connection list 24 are Alive. The notation such as (3-1) in the following sentence indicates “Step 3-1 shown in FIG. 3”.

  2, 5 and 6 show the distribution / switching function of the AP server 2m in the client PC 1n.

1. Normal Processing When the client AP 12 starts communication with the AP server 2m, it calls the connection destination determination component CA (5-1). The connection destination determination component CA calls the CL connection destination information holding component CB (5-1). The CL connection destination information holding component CB selects and acquires one of the AP communication addresses 17m of the AP server 2m stored in the CL connection destination list 14 according to a predetermined priority (5-2).

  Acquisition is successful (acquisition is possible at 5-3) when the AP status 18m of the AP server 2m is Alive or Busy. When there is an Alive AP server 2m, the AP communication address 17m of the Busy AP server 2m is not selected. The communication component CE communicates with the AP server 2m designated by the acquired AP communication address 17m (5-4).

  The connection destination switching component CC receives this communication result and confirms that the communication is normal (both 5-6 and 5-8 are normal). Thereafter, the client AP 12 is communicatively connected to the AP server 2m, and executes business processing in cooperation with the server AP 22 on the AP server 2m (5-10). If no error occurs in the business process (normal in 5-12), the client AP 12 ends the process.

  Even if the communication with the AP server 2m can be performed normally, the AP server 2m may fail to communicate with the DB server 3p. This occurs when all the DB servers 3p have a failure. In this case, the client AP 12 receives a notification to that effect from the server AP 22 (an error occurs in 5-12). Upon receiving this notification, the CL connection destination information holding component CB updates all AP statuses 18m in the CL connection destination list 14 to Dead (5-13). Then, the client AP 12 activates the connection teacher death detection component CD, performs polling (5-13), and waits for recovery from the failure.

2. Processing when the current connection destination AP server 2m is overloaded The connection destination switching component CC has a response time exceeding the predetermined allowable time 1 in communication (5-4) of the communication component CE. Is detected). In response, the CL connection destination information holding component CB updates the AP status 18m in the CL connection destination list 14 to Busy (5-7).

  Thereafter, the client AP 12 waits for the communication to end, and when it ends normally (normally 5-8), executes the business process as it is (5-10). At this normal end, the client AP 12 activates the connection teacher death detection component CD and performs polling, and then activates the connection destination determination component CA again to acquire the AP communication address 17m of another AP server 2m (5). -2) You may do it.

3. Processing when current connection destination AP server 2m has a failure The connection destination switching component CC detects that a connection error has occurred in communication (5-4) of the communication component CE (an error occurs in 5-8). This connection error is detected when communication exceeds a predetermined allowable time 2 (longer than allowable time 1). Upon receiving this, the CL connection destination information holding component CB updates the AP status 18m in the CL connection destination list 14 to Dead (5-9). The client AP 12 activates the connection teacher death detection component CD and starts polling (5-9), and then activates the connection destination determination component CA again, so that another AP server 2m that is lower in the predetermined priority order AP communication address 17m is acquired (5-2).

4). Processing when all AP servers 2m fail
When the AP statuses 18m of the AP server 2m registered in the CL connection destination list 14 are all Dead, the connection destination determination component CA fails to acquire (5-2) the AP communication address 17m. In this case (cannot be acquired in 5-3), the client AP 12 does not perform communication using the communication component CE, and performs business processing within a range that can be independently processed locally (5-6, 5-11). At this time, the client AP 12 uses the local DB 15 as necessary.

5. Processing when AP server 2m is restored
Recovery of the AP server 2m is monitored by polling of the client PC 1n shown in FIG. This polling is performed for all AP servers 2m in which the connection teacher death detection component CD is registered in the CL connection destination list 14.

  When the polling starts, the component acquires the AP communication address 17m from the CL connection destination list 14, and communicates with the AP status return component AF on the AP server 2m using the communication component CE (6-2). When this communication is normal (normal in 6-3), the connection teacher death detection component CD receives all the DB statuses 28p in the AP connection destination list 24 from the AP status return component AF.

  The connection teacher death detection component CD checks the DB status 28p (6-4). When there is a normal (Alive or Busy) DB server 3p (becomes 6-5), this component passes through the CL connection destination information holding component CB, and the AP server 2m in the CL connection destination list 14 The AP status 18m is updated (6-7).

  This process is as follows. If the connection teacher death detection component CD receives the DB status 28p indicating Alive from a certain AP server 2m, the AP status 18m of the AP server 2m is set to Alive. When the Alive DB status 28p is not received but the one indicating Busy is received, the same component sets the AP status 18m of the AP server 2m to Busy. If all the DB statuses 28p received from an AP server 2m are Dead, the AP status 18m of the AP server 2m is set to Dead.

  For all AP servers 2m that have polled, if communication abnormality (abnormality in 6-3) or all DB statuses 28p are abnormal (Dead) (nothing in 6-5), poll again after a certain time ( 6-6).

  In addition, the above process (process) is a connection process (5-1, 5-2, 5-3, 5-4), an acquisition process (5-6, 5-8, 6-2, 6-3, 6). -4, 6-5) and memory steps (5-7, 5-9, 5-13, 6-7). These processes are executed by the client middleware 13. FIG. 9 shows this state.

  Polling is performed at the time of initial setting of the system and at regular intervals thereafter.

  2, 7 and 8 show the transfer / switching function of the DB server 3p in the AP server 2m.

1. Normal operation The server AP 22 calls the connection component AA when starting communication with the DB server 3p (7-1). The connection component AA calls the status acquisition component AB to acquire a list of identifiers (DB_ID 26p) of the DB server 3p in the priority order to be connected in correspondence with a specific distribution key (for example, store code) (7-2). . The connection component AA selects the DB_ID 26p of the DB server 3p having the highest priority from the list. Then, the component acquires the DB communication address 27p of the DB server 3p from the AP connection destination list 24 via the AP connection destination holding component AC (7-3). Acquisition succeeds (acquisition is possible in 7-4) is when there is a DB server 3p whose DB status 28p is Alive or Busy. When there is an Alive DB server 3p, the DB communication address 27p of the Busy DB server 3p is not selected.

  The connection component AA communicates with the selected DB server 3p. If the communication is normal (normal in 7-6), the server AP 22 is communicatively connected to the DB server 3p, and accesses the database on the DB server 3p to execute the business process (7-8). If no error occurs in the business process (normal in 7-9), the server AP 22 ends the process.

  If the communication with the selected DB server 3p is abnormal (error in 7-6), the connection component AA acquires the DB communication address 27p of the DB server 3p with the lower rank in the above list and tries to connect ( 7-7).

2. Processing when the current connection destination DB server 3p fails When the server AP 22 fails while accessing the database (DB server 3p) (error 7-9), an access error is returned to the server AP 22 (7- Ten). In this case, since the data in the database may be in an incomplete state, this error is reported to the server AP 22 in a form different from the connection error. This error is also notified from the server AP 22 to the client PC 1n (5-12).

  In the DB server 3p, the DB status monitoring part DA detects an abnormality such as a failure (Dead state) or a response delay (Busy state), and updates the state information of the database held by the status management part DD. This information is reflected in the DB status 28p of the AP connection destination list 24 through polling in FIG.

3. Processing when all DB servers 3p are faulty Status acquisition component AB detects that all DB servers 3p are faulty (cannot be acquired in 7-4), and issues a DB connection error to server AP22. Notify (7-5). This error is also notified from the server AP 22 to the client PC 1n (5-12). The client PC 1n updates the AP status 18m in the CL connection list to Dead (5-13).

4). Processing when DB server 3p is restored
When the DB status monitoring component DA monitors the status of the DBMS 32 and determines that the status is normal, the status management component DD holds the status. The status information of this database is reflected in the DB status 28p of the AP connection destination list 24 by polling of the AP server 2m in FIG.

  The AP server 2m periodically polls the status of all DB servers 3p based on the AP connection destination list 24. In this polling, the polling component AE first communicates with the communication standby component DC waiting on the DB server 3p (8-1).

  If this communication is normal (normal in 8-2), the polling component AE receives the status information of the database and checks the status information (8-3). The database status information is generated by the DB status monitoring component DA monitoring the status of the DBMS 32 in the DB server 3p. The status information of the database is held by the status management component DD, and is notified to the polling component AE by the communication standby component DC.

  The polling component AE updates the DB status 28p of the AP connection destination list 24 via the AP connection destination information holding component AC based on the contents of the state information in the database. The polling component AE sets Alive if the database status information is normal (normal in 8-4) (8-5), and if abnormal (abnormal in 8-4), sets Busy or Dead (8- 6). If an error occurs in communication with the DB server 3p (the error occurs in 8-2), the part sets Dead (8-6).

  The effect of the present embodiment is that the cost of hardware for load distribution can be reduced. Furthermore, the second effect is that a single point of failure related to load distribution can be removed.

  The reason is that the client middleware 13 can realize the transfer / switching function of the AP server 2m by referring to the CL connection destination list 14, and therefore it is not necessary to place a load distribution device.

  The third effect is that there is no delay in switching when the DB server 3p fails. The reason is that, in the polling of the DB server 3p performed by the AP server 2m, the AP server middleware 23 and the DB server middleware 33 exchange information by non-blocking communication.

  The fourth effect is that the client AP 12 can detect and cope with the occurrence of the failure of the DB server 3p and the recovery without communicating with the DB server 3p. The reason is that the state information of the DB server 3p is used to reach the client PC 1n via the AP server 2m.

  The client middleware 13, the AP server middleware 23, and the DB server middleware 33 may all be realized as dedicated hardware. Alternatively, these functions may be realized by a program being stored in a memory and a processor executing the program.

  The second embodiment of the present invention is as follows. In the store system 10 of the first embodiment, only when all the AP servers 2m have a failure, the client AP 12 performs local processing independently (5-3, 5-5, 5-11 in FIG. 5). In the second embodiment, the client AP 12 basically performs local processing independently, and connects to the AP server 2m when a problem occurs in the local processing. As a result, the present invention can be applied to an application mainly based on local processing.

  The third embodiment of the present invention is as follows. The store system 10 of the first embodiment activates polling when the connected AP server 2m has a failure (5-9 in FIG. 5). In the third embodiment, polling is activated only when all the AP servers 2m have a failure. When the recovery detection delay of the AP server 2m is allowed, the occurrence frequency of polling can be lowered.

  The fourth embodiment of the present invention is as follows. The store system 10 of the first embodiment activates polling when the connection destination AP server 2m has a failure (5-9 in FIG. 5). Thereafter, the store system 10 of the first embodiment activates the connection destination determination component CA again, acquires (5-2) the AP communication address 17m of another AP server 2m that is lower in the predetermined priority order, and Connect to another AP server 2m (5-4). After the connection, the store system 10 of the fourth embodiment, when connected, detects that the upper AP server 2m is normal with a predetermined priority from the other AP server 2m by polling. Reconnect to server 2m. This may be done automatically by the connection teacher death detection component CD. Alternatively, the component may only notify the client AP 12 and the client AP 12 may reconnect at an appropriate timing. Thereby, when there is a difference in processing capability between the AP servers 2m, appropriate load distribution can be achieved.

  The fifth embodiment of the present invention is as follows. In the store system 10 of the first embodiment, when all the AP servers 2m have a failure, the client AP 12 performs local processing independently (5-3, 5-5, 5-11 in FIG. 5). When the store system 10 of the fifth embodiment detects that there is a normal AP server 2m by subsequent polling, it stops local processing and connects to the AP server 2m. This may be done automatically by the connection teacher death detection component CD. Alternatively, the component may only notify the client AP 12, and the client AP 12 may connect at an appropriate timing. Thereby, it is possible to quickly cope with the recovery of the AP server 2m.

  The sixth embodiment of the present invention is as follows. In the above-described embodiment, the AP server 2m and the DB server 3p are different servers. However, in the sixth embodiment, the AP server 2m and the DB server 3p may be combined and implemented as a single server computer. In this embodiment, a failure or performance degradation of the DBMS 32 in the same server is monitored as a failure or performance degradation of the DB server 3p. According to the present embodiment, a system using the present invention can be realized at low cost.

It is a figure which shows the whole structure of a store system. It is a figure which shows the internal structure of a client and a server. It is a figure which shows the structure of CL connection destination list. It is a figure which shows the structure of AP connection destination list. It is a flowchart of a connection process of a client AP. It is a flowchart of the polling process which a client PC performs. It is a flowchart of the connection process of server AP. It is a flowchart of the polling process which server AP performs. It is a figure which shows the structure of a client PC.

Explanation of symbols

10 Store system 1n Client PC
12 Client AP
13 Client middleware 14 CL connection list 16m AP_ID
17m AP communication address 18m AP status 15 Local DB
CA connection destination determination component CB CL connection destination information holding component CC connection destination switching component CD connection teacher death detection component CE communication component 2m AP server 22 server AP
23 AP server middleware 24 AP connection list 26p DB_ID
27p DB communication address 28p DB status AA connection part AB status acquisition part AC AP connection destination information holding part AE polling part AF AP status return part 3p DB server 32 DBMS
33 DB server middleware DA DB status monitoring component DD status management component DC communication standby component

Claims (14)

A destination list stored in storage, and
A terminal AP;
Based on the first information acquired from each of the plurality of connected first servers, the state information of each of the plurality of first servers is stored in the connection destination list, and based on the state information of the plurality of first servers. A terminal program that selects one of the plurality of first servers and performs communication connection between the selected first server and the terminal AP ,
Each of the plurality of first servers receives the first information including the state information of the second server generated based on the second information acquired from all the second servers connected to each of the first servers. Acquired,
A terminal device that updates the state information of the first server stored in the connection destination list based on the state information of the second server included in the first information . Requesting the transmission of the first information to the plurality of first servers when information indicating normality is not included in the status information of the second server included in the acquired first information; The terminal device according to claim 1. State information of the second server included in the first information when the state information of the second server included in the acquired first information includes at least one piece of information indicating normality The terminal device according to claim 1, wherein state information of the first server stored in the connection destination list is updated based on the connection destination list . When information indicating an error transmitted by the first server when an error occurs in communication between the first server and the second server is received, the first server stored in the connection destination list The terminal device according to any one of claims 1 to 3, wherein all of the state information is updated to information indicating that there is a failure . When all the status information of the first server stored in the connection destination list is information indicating a failure, the terminal program transmits the first information to the plurality of first servers. The terminal device according to claim 1 , wherein the terminal device is requested . The first information is updated when at least one of the state information of the first server is updated based on the first information transmitted based on the request for transmitting the first information. The terminal device according to claim 5, connected to a server . System comprising the plurality of first servers, and the second server, and a terminal device according to any one of claims 1 to 6. Computer
It acquires first information from each of a plurality of first server connected to said computer,
The status information of each of the plurality of first servers is stored in the stored connection destination list to the storage based on the first information,
There line communications connection between the plurality of terminals AP mounted on the first server and the computer that the selected by selecting one from the plurality of first server based on a first server state information,
Acquired by receiving the first information including the state information of the second server generated based on the second information acquired from all the second servers connected to each of the plurality of first servers. And
A terminal control method for updating state information of the first server stored in the connection destination list based on state information of the second server included in the first information . State information of the second server included in the first information when the state information of the second server included in the acquired first information includes at least one piece of information indicating normality The terminal control method according to claim 8 , wherein state information of the first server stored in the connection destination list is updated based on the connection destination list . When the computer receives information indicating an error transmitted by the first server when an error occurs in communication between the first server and the second server, the computer stores the information indicating the error in the connection destination list. The terminal control method according to claim 8 or 9, wherein all of the state information of the first server is updated to information indicating that there is a failure. On the computer,
A processing you get the first information from each of a plurality of first server connected to said computer,
A processing you store status information of each of the plurality of first server to the destination list stored in the storage based on the first information,
And row intends process communication connection between the terminal AP, which is mounted on the first server and the computer that the selected by selecting one from the plurality of first server based on said plurality of first server state information ,
Acquired by receiving the first information including the state information of the second server generated based on the second information acquired from all the second servers connected to each of the plurality of first servers. Processing to
The terminal program which performs the process which updates the status information of the said 1st server memorize | stored in the said connection destination list based on the status information of the said 2nd server contained in the said 1st information . Processing for requesting transmission of the first information to the plurality of first servers when the status information of the second server included in the acquired first information does not include information indicating normality The terminal program according to claim 11, wherein the computer is executed . State information of the second server included in the first information when the state information of the second server included in the acquired first information includes at least one piece of information indicating normality The terminal program according to claim 11 or 12, which causes the computer to execute a process of updating the state information of the first server stored in the connection destination list based on the information . When information indicating an error transmitted by the first server when an error occurs in communication between the first server and the second server is received, the first server stored in the connection destination list The terminal program according to any one of claims 11 to 13, which causes the computer to execute a process of updating all of the state information to information indicating that there is a failure .

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