JP2003333072A - Information processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restore a relation of an application and a lower stage layer using small loss, when line break and reconnect on active line occur during operation of application in a portable terminal enabling communication, and the like. <P>SOLUTION: In an information processing device, in which TCP/IP communication is carried out by using PPP and the line is reconnected when a line break occurs, the communication of an application layer is interrupted, only when the IP address changed after reconnection or the reconnection failed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a data communication device that performs CP / IP communication.

[0002]

2. Description of the Related Art When TCP / IP communication is performed using a telephone line or the like, PPP is currently generally used. When the connection is started, PPP arbitrates the parameters necessary for establishing the data link layer using LCP, and when the data link layer is established, next, using IPCP, TCP / TCP /
It arbitrates the parameters required for IP communication. I for this
The P address is also included.

When arbitration of IPCP is completed, TCP / IP
Communication becomes possible.

(Reference) RFC1661: The Point-to-Point
t Protocol (PPP) RFC1332: The PPP Internet
Protocol Control Protocol
(IPCP)

[0005]

In the ordinary PPP, once the physical layer such as a telephone line is disconnected, it is necessary to reconnect the LCP and IPCP after reconnecting. Therefore, the IP address may change.

When the IP address changes, HTTP or FTP
Communication of application layer such as can not be continued.

Therefore, there are the following two methods as measures when the PPP is disconnected.

1) When PPP is disconnected, upper layer communication is also interrupted. In this case, if the IP address is the same after reconnecting immediately, the communication in the upper layer is originally interrupted but the communication is unnecessarily interrupted.

2) Even if the PPP is disconnected, the upper layer has no effect. In this case, when the IP address is changed due to immediate reconnection, the upper layer application tries to continue communication with the previous IP address forever, but cannot actually communicate.

The above two measures are inconvenient and sometimes inconvenient.

Mobile communication using a mobile phone, etc., which has been increasing in number in recent years, is a particular problem because the connection is often disconnected unexpectedly depending on the radio wave condition.

[0012]

SUMMARY OF THE INVENTION The present invention solves such a problem, and if the physical layer is reconnected immediately when disconnected, the application is immediately affected when disconnected. It is characterized by notifying the application and notifying the application when the reconnection fails or when the reconnection succeeds but the IP address is different from the last time.

As a result, effective communication becomes possible when communication is temporarily interrupted and reconnection is made immediately.

Here, any means suitable for inter-program communication such as signals, software interrupts, event flags, etc. may be used as means for notifying the application. Alternatively, a method of abnormally ending a library call or system call that uses communication may be used.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) The present invention will be described in detail below with reference to the drawings. 1 and 2 are one embodiment of the present invention, in which a PPP connection is made using a mobile phone,
A data communication device that communicates by TCP / IP will be described.

FIG. 1 is a block diagram of the information processing apparatus. 1
Reference numeral 0 is a client machine that requests a connection from the server, and is composed of 11 CUPs, 12 memory devices, and 13 mobile phones. To realize this means CUP
The programs executed by are stored in 12 memory devices. An application program for performing TCP / IP communication using PPP is also stored in the memory device 12, and is executed by 11 CUPs. The place where the program is stored may be another medium such as an external storage device.

A server machine 20 accepts a connection request from a client, and comprises a CUP 21, a memory device 22 and a modem 23. The program for implementing this means is stored in the memory device 22 or another medium. Reference numeral 30 is a telephone line to which modems of both the client and the server are connected. The server is connected to other data communication devices via the network 40.

The client 10 and the server 20 are connected by PPP, and the client 10 communicates with the server 20 or a data communication device on the network 40 by using TCP / IP as a network layer protocol.

Next, the operation of this system will be described with reference to FIG.
This will be described with reference to the flowchart of. FIG. 2 is a flowchart showing the operation regarding PPP when the present invention is applied to a client machine.

The operation of the client machine 10 will be described. When the client 10 which has already performed the PPP communication with the server 20 loses the communication at C0, the mobile phone 13 is used at C1 to try to reconnect the PPP with the server 20 via the modem 23. The phone doesn't connect here, P
When reconnection is not possible due to failure of arbitration in PP LCP or IPCP, the process proceeds to C5. Also C
If reconnection is successful in 1, the IP after reconnection in C2
Check if the address is the same as the previous IP address. If the IP address is the same here, it transits to C4 and TCP / IP has no effect on the application.
Communication can continue.

When reconnection fails at C2 and IP at C3
If the address is different from the previous one, the operation transits to C5. In C5, an event (“reconnection failed” or “IP address changed”) corresponding to the application communicating with TCP / IP is notified. The application notified of the event disconnects the communication in use because the TCP / IP communication until then cannot be continued. If the event notified here is “IP address has changed”, communication can be started again with a new IP address if necessary.

In this way, if the PPP reconnection succeeds and the IP address does not change, the communication of the application can be continued, and in other cases, the application can interrupt the communication.

(Second Embodiment) Next, an embodiment of the present invention in which the client machine repeats reconnection several times will be described. FIG. 3 is a flowchart showing the operation of the client machine 10 relating to PPP in this embodiment.

Similar to the first embodiment, the client machine tries to reconnect when the line communicating with the server is disconnected. The portions other than C7, C8, and C9 are the same as those in the first embodiment.
The description is omitted because it is the same as.

When the line is disconnected at C0, 0 is substituted for a variable "failed" that counts the number of connection failures at C7 before attempting PPP reconnection at C1.

If the reconnection fails at C2, the process proceeds to C8 and the value of the variable'failed 'is incremented by 1. In C9, if the value of'failed 'has exceeded the specified number of reconnections (3 times in this example), the process transitions to C5, but if it does not exceed the specified number of reconnections, the process transitions to C1 and then again. Reconnect.

In this way, the present invention can be applied to a system in which reconnection is repeated until the specified number of times is exceeded, and if the reconnection is still unsuccessful, the communication is terminated.

[0028]

As described above, according to the present invention, in a communication device that reconnects immediately when PPP is disconnected, if the IP address is not the same as the previous connection when reconnecting, the IP address is changed. By notifying other programs of this, the application layer communication can be continued when the IP address is not changed, and the application layer communication can be terminated when the IP address is changed or reconnection fails. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of an information processing apparatus that is an embodiment of the present invention.

FIG. 2 is a configuration diagram of an information processing apparatus that is an embodiment of the present invention.

FIG. 3 is a PP of a client machine 10 according to this embodiment.
7 is a flowchart showing an operation regarding P.

[Explanation of symbols]

10 Client body 11 Client CUP 12 Client memory device 13 Client modem device (mobile phone) 20 server body 21 Server CUP 22 Server memory device 23 Server modem device 30 telephone lines Network with 40 servers

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5B089 GA21 HB02 HB03 KA01 KB06                       KG06                 5K030 HA08 JL01 JT09 LB01                 5K034 AA02 DD01 EE03 EE12 FF01                       FF02 FF13 GG02 KK21 LL01                       LL02 SS00 SS02

Claims (6)

[Claims] 1. A communication device for performing TCP / IP communication using PPP and immediately reconnecting when PPP is disconnected, in a case where the IP address is not the same as that of the previous connection when reconnecting. An algorithm that notifies other programs that an address has changed. 2. An algorithm that, in a communication device that reconnects immediately when the PPP is disconnected, notifies another program of that when reconnection fails. 3. A program for controlling the data communication device as the above algorithm. 4. A data communication device equipped with the above-mentioned PPP program. 5. A system in which two data communication devices are combined. 6. Each of said devices, algorithms, media.