JP2007151159A - E-mail proxy server device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an e-mail proxy server device for conducting an e-mail deletion process, without being affected by communication disconnection, in place of an e-mail server. <P>SOLUTION: A proxy server 2 has a provisional e-mail box 2a, is disposed between an e-mail server 3 and a mobile communication network, and acts for the e-mail processing function suitable for the mobile communication network in place of the e-mail server 3. An e-mail box 3a stores a message in an e-mail including a long sentence message, and the provisional e-mail box 2a stores a message in an e-mail including a short sentence message frequently used in the mobile communication network. Additionally, for confirming a message regarding a receiving notification, an abbreviated message is stored in respect to the e-mail including the long sentence message. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mail proxy server acting on behalf of a mail server. In particular, the present invention relates to a mail proxy server that performs processing suitable for a mail system in a mobile communication network.

The spread of digital mobile communication systems is remarkable, and support for data communication is regarded as important in mobile communication. For this reason, PDC-P (PDC Packet) based on PDC (Personal Digital Cellular), GPRS (General Packet Radio System) based on GSM (global system for mobile communication), IS-95 based Packet methods such as HDR (High Data Rate) method have been developed.
By using data communication using such a packet system or the current circuit switching system, it is possible to send and receive mail and access the Internet.

FIG. 7 is a system configuration diagram of a mobile communication network in which a mail system is constructed.
The mobile communication network has a large number of cells, and radio communication control for mobile devices (mobile communication terminals) 71a and 71b located in each cell is performed by the base station of each cell. In FIG. 7, two cells A and B are illustrated as an example, and base stations 72 and 73 are installed in each cell, and mobile devices 71a and 71b are located in each cell.
MSC (Mobile Switching Center) 74 is a switching node for mobile communications, SMSC (Short Message Service Center) 75 is a service node that relays, stores and forwards short messages, and DAS (Direct Access System) 76 supports circuit switching bearers. PMSC (Packet Mobile Switching Center) 77 is a switching node that supports a packet bearer, and GSN (GPRS Support Node) 78 is a switching node that supports a GPRS packet bearer.

Reference numeral 79 denotes a mail server of this mobile communication network. An SMTP server 79a, an extended POP server 79b, and a mail box 79c having mail addresses of the mobile devices 71a and 71b are provided.
Simple Mail Transfer Protocol (SMTP) and Post Office Protocol Version 3 (POP3) are standard protocols for Internet mail. SMTP is a protocol for delivering / forwarding outgoing mail from a client (mobile device) to the mailbox of the other client (mobile device) and storing the message. POP3 is a protocol for a client (mobile device) to access a mailbox and retrieve mail addressed to itself. Extended POP3 is a protocol in which the applicant has expanded the functions of the POP3 protocol described above.
The base stations 72 and 73 are connected to the MSC 74 and the GSN 78. The MSC 74 is connected to the mail server 79 via the SMSC 75, DAS 76, and PMSC 77, and the GSN 78 is also connected to the mail server 79.

A case where the mobile device 71a transmits a mail to the mobile device 71b using the packet bearer service by the PMSC 77 will be described.
A mail is transmitted from the mobile device 71a to the SMTP server 79a via the base station 72, the MSC 74, and the PMSC 77. The SMTP server 79a distributes the mail message to the mail address of the destination client (mobile device 71b) and stores the mail message in the mail box 79c in the mail server 79. The SMTP server 79a sends an incoming notification (new message notification, notification) to the SMSC 75 via the MSC 74 and the base station 73 to notify that the message is stored to the destination client (mobile device 71b). Make it.

  Next, when the destination client (mobile device 71b) requests the extended POP3 server 79b to acquire received mail (download to the mobile device 71b) using the extended POP3 protocol, for example, via the MSC 74 and PMSC 77. The extended POP3 server 79b reads the mail from the mail address of the destination client (mobile device 71b) in the mail box 79c, and causes the client (mobile device 71b) to acquire it via the PMSC 77, MSC 74, and base station 73. .

Unlike emails sent and received between users of general personal computers, emails sent and received between users of mobile devices 71a and 71b are often short in the length of email messages and do not have attached files. There are features. Conventionally, such short message mail accounts for 90% or more of the capacity stored in the mail box 79c.
However, since short message mail can be stored in a small-capacity mailbox, it is not necessary to store the message in a general large-capacity mailbox, so it is necessary to transfer it to a mail server equipped with a large-capacity mailbox. Absent.
As described above, there is room for improvement in a mail system that uniformly stores mail messages having different message sizes in the mail box 79c.

In addition, as described in Patent Document 1, the short message that the above-mentioned SMSC 75 notifies an incoming call is an operation that performs an incoming call notification including text data of 128 × 3 = 384 characters from the beginning of the stored message. Has been made.
By knowing part of the message content, the user can determine whether the mobile device 71b acquires the message stored in the mail box 79c (whether to download to the mobile device 71b). It is possible to prevent the mobile device 1b from acquiring advertisement mails or spam mail messages that do not need to be acquired until a data communication fee is paid.

However, standardization of the short message service is being considered at the SMS Forum. In the SMS Forum standard, only the fact that a mail has arrived is notified, and the header of the incoming mail and the message contents are unknown. Therefore, the above-described short message in operation may not conform to the standard.
In addition, it is difficult for the above-described incoming notification service in operation to adopt a charging method such that a simple incoming notification is free and an incoming notification service that notifies a part of the body of an email is charged.

In addition, mobile users often have a mail address of a service provider (ISP) mail server on the Internet. Since the mobile device is carried by the user, it will not only receive the incoming notification of the mail received in the mailbox of the mail system for the mobile communication network, but will also receive it at the user's email address in the ISP mailbox. It is also suitable for receiving notifications of incoming mail.
Traditionally, mail that has been received in the ISP's mailbox as it is is transferred to the mobile user's mailbox as it is, a “forwarding service”, or edited mail, such as only part of the message header when forwarding There was an "incoming call notification service" that forwards.
However, since it is not integrated with the “incoming notification service” in the mail system in the mobile communication network, there is room for rational processing.

In addition, the wireless communication line between the base station and the mobile station may be disconnected due to the radio wave condition. If communication is cut off during the mail message deletion process, mail inconsistency occurs between the mobile device and the mailbox.
FIG. 8 is a sequence diagram for explaining processing for deleting a mail message in the mobile communication network shown in FIG.
Assume that a sequence in which the mobile device 71b first acquires a mail message from the extended POP3 server 79b is executed. Thereafter, it is assumed that a mail deletion command “DELE 0, JUID” 81 is transmitted from the mobile station to the extended POP3 server 79b.
Note that 0 of the first argument is a value contrary to the standard of the POP3 protocol, and the POP3 server does not respond, but only the extended POP3 server responds to this request signal. The JUID of the second argument is a unique ID that can identify mail, and corresponds to the UID in the POP3 protocol standard.

Upon receiving the mail deletion command “DELE 0, JUID” 81, the extended POP3 server 79b adds a deletion flag to the mail message specified by the second argument JUID, and starts an auto logout timer.
Although not shown, in normal processing, the extended POP3 server 79b thereafter transmits an acknowledgment “+ OK” to the mobile device 71b, and the mobile device 71b transmits a “QUIT” command to the extended POP3 server 79b. . The “QUIT” command is a command for requesting logout, ends the transaction state, and updates (updates) the mailbox.
The extended POP3 server 79b receives the “QUIT” command, deletes the message with the deletion flag added from the mail box 79c, and transmits an affirmative response “+ OK” to the mobile device 71b.

However, as shown in FIG. 8, after transmitting the delete command 81 and before transmitting the “QUIT” command, the mobile device 71b moves into the tunnel or the like and becomes squelched, or moves out of range, Assume that the communication is cut off for some reason. Assume that the mobile device 71b detects that the mobile device 71b has been disconnected, and requests the extended POP3 login again.
In this login request, the mobile device 71b transmits a “USER” command 82 having an authentication user name (username) as an argument to the extended POP3 server 79b. However, when the auto logout timer is running, this “USER” command 82 is not accepted, and a negative response “-ERR” (not shown) is transmitted from the extended POP3 server 79b, and login is rejected. Therefore, “JUID” There is a problem that email messages corresponding to are not deleted.

  As described above, in the POP3 protocol, when a series of requests such as message acquisition and deletion are accepted in the transaction state and the transaction state is terminated, the mailbox is updated and the deletion is executed. For this reason, if communication is cut off in the transaction state, the deletion is not executed, so that the messages on the mobile device side 71b and the mailbox 79c side do not match.

Therefore, in the specification filed in Japanese Patent Application No. 2001-286226 (September 20, 2001) preceding this application, if the “USER” command 82 is received even when the auto logout timer is activated, the “QUIT” command Is deleted from the mail box 79c, and an acknowledgment “+ OK” 83 is transmitted to the mobile device 71b.
If the auto logout timer times out without the “USER” command 82 being transmitted from the mobile device 71b, it is considered that the “QUIT” command 82 has been received at this point, and similarly, the mail with the deletion flag added thereto is considered. The message is deleted, and an acknowledgment “+ OK” 83 is transmitted to the mobile device 71b.
If a protocol specialized for a mail system of a mobile communication network is adopted as in the above-described prior art extended POP3, a general-purpose mail server cannot be used as it is. In addition, there is a problem in that it cannot be interconnected with a general-purpose mail server employed in an Internet service provider (ISP) mail server transferred via the Internet.

JP2001-197553A (FIG. 22)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a mail proxy server that performs message deletion processing on behalf of a mail server and is not affected by communication disconnection. is there.

In the first aspect of the present invention, in the mail proxy server apparatus, among the mails received from the client registered in the mail system to the mail address of the client, the “message deletion request” At the same time, when the “request signal to execute the deletion” is received, the “request signal for requesting message deletion” of the specified mail is sent to the mail server provided with the mailbox storing the message of the specified mail. Deletion that causes the mail server to perform message deletion of the specified mail by transmitting a "request signal for executing deletion of a message for which message deletion is requested" after the mail server has responded normally It has a control means.
Therefore, even if the communication line is interrupted after sending a "request signal to execute the deletion at the same time as the message deletion request" between the client and the proxy server, the mail message stored in the mailbox is deleted as requested. it can.

According to the second aspect of the present invention, the mail proxy server device stores a mail message received to a client mail address registered in the mail system or a message in which the mail message is shortened. When a “request signal to execute the deletion at the same time as the message deletion request” of the specified mail among the mails received to the mail address of the client is received from the client , Deleting the designated mail message stored in the temporary mailbox, or the shortened message of the designated mail message, and storing the designated mail message. If there is a mailbox, “Request signal for requesting message deletion” of the designated mail is sent to the mail server provided, and after the mail server responds normally, “Request signal for executing deletion of message requested to delete message” Is sent to the mail server to cause the designated mail to be deleted.
Therefore, even if communication disconnection occurs after sending a “request signal to execute the deletion simultaneously with the message deletion request” between the client and the proxy server, the designated mail message stored in the temporary mailbox, Alternatively, you can delete a shortened message for a specified mail message, and if there is a mailbox that stores a specified mail message, delete the mail message stored in this mailbox as requested. it can.

The invention according to claim 2 described above can be applied to the following first to sixth mail proxy server devices.
A detecting means for detecting that a mail addressed to a client mail address registered in the mail system is received, and a determination for determining whether the message is a long message or a short message according to at least a data size of the mail message Means, a temporary mailbox for storing the mail message, a shortening means for shortening the mail message, and the mail message detected by the detecting means is the short message by the determining means. When it is determined, the message of the mail is stored in the temporary mailbox, and when it is determined that the message is the long message, the message of the mail is shortened by the shortening means to the temporary mailbox. In the mail address First mail proxy server apparatus characterized by to deliver the mail to the mail server with a mailbox has a distribution control means, for storing the message of the mail having an address.
Accordingly, by arranging the mailboxes in a distributed manner, the temporary mailbox stores messages of a small size, so that it is easy to store and retrieve received email messages. Since the communication traffic to the mail server is greatly reduced, the communication capacity with the mail server can be reduced. On the other hand, since a general-purpose server can be used as a mail server provided with a mailbox, it is possible to store and retrieve received mail messages using the functions of the existing general-purpose mail server.

In the first mail proxy server apparatus described above, when a request for obtaining the message of the mail detected by the detection unit is received from the client, the temporary mail box or the mail server mail box, A second mail proxy server apparatus, comprising: an acquisition control unit that accesses a mail message stored therein and causes the client to acquire the mail message.
Therefore, the client can acquire the message stored in the mailbox. When acquiring short messages that are frequently used, it is not necessary to access the mail server, so that communication traffic with the mail server is reduced and access time is reduced.

Detection for detecting that the mail addressed to the client registered in the mail system is received in advance from another mail address of the mail system different from the mail system, which is related to the mail address in advance. Means for determining whether the message is a long message or a short message according to at least the data size of the mail message, a temporary mailbox for storing the mail message, and shortening the mail message When the determination unit determines that the e-mail message detected by the detection unit is the short message, the e-mail message is stored in the temporary mailbox, and the long message is stored. When it is determined that the message is a message, A delivery control means for shortening the message of the mail by means and storing it in the temporary mailbox and preventing delivery to a mail server having a mail box having a mail address of the destination of the mail. The 3rd mail proxy server apparatus characterized by these.
Therefore, as with the first mail proxy server device, there is an operational effect due to the distributed arrangement of mailboxes. In addition, mail messages transferred from other mail addresses of different mail systems are not stored in the mailbox of this mail system, so that communication traffic to the mail server is reduced and memory required for the mailbox is stored. Capacity can be reduced.

In the third mail proxy server apparatus described above, when a request for acquiring the mail message detected by the detection unit is received from the client, the mail is addressed to the mail address of the client registered in the mail system. The temporary mail box in which the message of the mail is stored or the other if the mail address is forwarded from another mail address different from the mail system. A fourth mail proxy server device, comprising: an acquisition control unit that accesses a mail server including a mailbox with a mail address of, and causes the client to acquire a message of the mail.
Therefore, the client can acquire the transfer source message stored in the mailbox of another mail address in a mail system different from this mail system.
If the temporary mail box is always accessed when the mail is a short message, it is not necessary to access a mail system different from the mail system, and communication traffic is reduced.

In any of the first to fourth mail proxy server devices described above, by notifying the short message service center of the reception of the mail detected by the detection means, the mail address of the mail destination is changed. A fifth mail proxy server device comprising notification means for notifying a given client of an incoming call.
Therefore, the client can immediately know that the mail has been received.

In any of the above-described first to fifth mail proxy server devices, when receiving a message confirmation request for the mail detected by the detection means from the client, the temporary mail box is accessed. And an acquisition control means for causing the client to acquire the short message of the mail stored in the temporary mailbox or a message obtained by shortening the long message of the mail. Mail proxy server device.
Therefore, in the case of a long message, the client can determine whether or not to acquire the entire long message by acquiring a message obtained by shortening the long message and confirming the content.
In either case, since it is not necessary to access the mail server, communication traffic with the mail server is reduced, and the time required for access is reduced.
A standardized general-purpose device can be used for the short message service center. Even when a general-purpose device is used, the size to be acquired for message confirmation can be determined without being restricted by the short message service standard. It is also easy to make a simple incoming call notification service free, and to make a paid option a service that can acquire and check at least part of the contents of received mail.
The request for confirming the content of the received mail may be automatically executed by the client device in conjunction with the client receiving a simple incoming notification, or may be executed by a user operation of the client. .

  According to the present invention, there is an effect that a message deletion processing function that is not affected by communication disconnection can be performed on behalf of a mail server.

FIG. 1 is a configuration diagram of a mail system for explaining an embodiment of the present invention. Since the basic configuration of the mobile communication network is the same as the system configuration shown in FIG. 7, the relay switching node, base station, etc. are omitted in this figure. Although mobile devices of different generations are mixed in the mobile communication network, here, mail processing for a third generation mobile device will be described.
In the figure, reference numerals 1a and 1b denote mobile units, which correspond to 71a and 71b in FIG. 7, but a protocol for obtaining mail received from a mailbox is an improved version of the extended POP3 protocol described in the prior art. use.

The extended POP3 protocol is based on POP3 and incorporates a part of the IMAP4 protocol function described later in order to enable partial acquisition of multipart messages. For example, it is possible to acquire a header part, body text, an attached file, one of a plurality of attached files, a specific received mail among a plurality of received mails, etc. in a message of one received mail. In addition, it is possible to acquire mail in a form suitable for a mobile device, such as acquisition of a mail list or acquisition for a specified size.
As the distribution / transfer protocol, the ESMTP (Extended SMTP) protocol, which is an extension of the SMTP protocol so that an 8-bit code can be used, is used. The ESMTP protocol is standardized by RFC1869, RFC1652, and the like. RFC (Request For Comments) is a standard of IETF (Internet Engineering Task Force).

Reference numeral 2 denotes a mail proxy server. It is provided between the mail server 3 and the mobile communication network, and performs a mail processing function suitable for the mobile communication network instead of the mail server 3. It can also be called a gateway in a messaging node. A temporary mail box (Temporary Mail Box) 2a for storing received mail is provided.
The mail server 3 is a general-purpose mail server and includes a mail box 3a inside. The ESMTP protocol is used as a mail delivery / transfer protocol with the mail proxy server 2. As a received mail acquisition protocol, IMAP4 (Internet Messaging Access Protocol 4), which is more complicated than POP3 but has advanced functions, is used.
The mail transfer agent (MTA) 4 of another generation is an interface for transferring mail to a mail server for a mobile device of a generation before the third generation mobile devices 1a and 1b. The ESMTP protocol is used with the mail proxy server 2.

Reference numeral 5 denotes the Internet. Reference numeral 6 denotes an Internet service provider (ISP) mail server, which includes a mail box 6a.
POP3 and ESMTP protocols are used with the mail proxy server 2, but a border mail transfer agent (B-MTA) 7 is passed in the direction of transfer from the Internet 5 to the mail proxy server 2. When there are a plurality of nodes connected to the Internet 5, each node is provided with a B-MTA 7 and is connected to one mail proxy server 2 from each node. When a plurality of mail proxy servers 2 are installed, sorting is performed according to the mail destination.

A short message service center (SMSC) 8 is a node corresponding to the SMSC 75 shown in FIG. 7, and has only a function of notifying incoming calls, and notifies the presence of some new mail. We do not inform you about the header information and title of the email. The SMPP3.4 (Short Message Peer to Peer Ver3.4) protocol defined by the SMS Forum is used with the mail proxy server 2.
Note that the SMSC 8 can simply send a delivery confirmation notification to the mobile device 1a that sent the mail.

Reference numeral 9 denotes a DRS (Directory Replication Server) which is a replica server of a subscriber information server (Directory Server) (not shown), and holds subscriber (user) attribute information of the mobile device.
Reference numeral 10 denotes a billing processing system and a customer comprehensive information system, which performs billing processing based on CDR (Charging Data Record, Call Detail Record) which is billing information. The mail proxy server 2 generates a CDR for a billing transaction among message transmission, message reception, delivery confirmation, incoming notification, message deletion, and the like.
Reference numeral 11 denotes a time server NTP (Network Time Protocol Server), which synchronizes the time of each server.

The function of the mail proxy server 2 described above will be described.
Separately from the mailboxes 3a provided in the mail server 3, provisional mailboxes 2a are provided to distribute the mailboxes.
A mail message having a long message is stored in the mail box 3a, and a mail message having a short message is stored in the temporary mail box 2a. In addition, a shortened message is stored for a mail having a long message for message confirmation to be described later.
As described in the section of the prior art, it is considered that mails between mobile communication terminals often have short messages and many have no attached files.

Therefore, by distributing the mailboxes that store the received mail messages according to the message size, mails with short messages that are frequently used in the mobile communication network can be used on the side closer to the mobile radio network. Messages are stored and retrieved, and mail messages with long messages that are infrequently used are transferred to a general-purpose mail server.
However, the mail transferred from the ISP mail server 6 can be prevented from being transferred to a general-purpose mail server even if it has a long message.

It is assumed that the SMSC 8 provides only a notification service (Push type service) to the user's mobile device 1a given the mail address of the received mail. The service that allows the user to acquire at least a part of the mail, confirm the message, and determine whether to acquire the entire long message is a proxy server from the client (mobile device side 1b) at the time of the simple incoming notification described above. This is realized by accessing 2 to obtain at least a part of the mail (pull type service).
Therefore, the temporary mail box 2a stores not only short messages but also messages obtained by shortening long messages.
Note that when the mail received in the mail box 6a of the ISP mail server is transferred to the mail address of the mobile device 1b, the ISP only needs to transfer the mail to the proxy server 2 without editing. .

As can be seen from FIG. 1, the mail server 3 employs the IMAP4 protocol while the mobile station 1b uses the extended POP3 protocol to obtain the received mail. The ISP mail server 6 employs the POP3 protocol. The mail proxy server 2 is stored in the mail box 3a by the mobile device 1b by executing processing for protocol conversion between the mobile device 1b and the mail server 3 and between the mobile device 1b and the ISP mail server 6. It is possible to acquire mail messages or mail messages stored in the mail box 6a.
The extended POP3 protocol stipulates a protocol so that the deletion process of the mail message stored in the mailbox 3a can be correctly performed even when the wireless communication line between the base station and the mobile station is disconnected.
That is, in the extended POP3 protocol, a “request signal for executing deletion at the same time as a message deletion request” is defined. In response to this request signal, the proxy server 2 transmits a “request signal for requesting message deletion”, and after the mail server has responded normally, a “request signal for executing deletion of a message for which message deletion has been requested”. The two steps of transmitting are executed.

In addition, the mail proxy server 2 specifies that the user of the mobile device 1b specifies the mail address of the mail to be rejected and registers it in the DRS 9 subscriber profile, so that the mail forwarded from the Internet 5 is B- It can be automatically rejected in MTA7.
In addition, when the user of the mobile device 1b tries to obtain a mail message stored in the mail box 3a or the temporary mail box 2a, the user specifies the mail address of the mail to be rejected in the same manner, Acquisition can be automatically rejected or messages can be deleted.

FIG. 2 is a block configuration diagram for explaining storage of a received mail message and simple incoming notification. The mail proxy server 2 includes an incoming call detection unit 21, a message determination unit 22, a message shortening unit 23, and a delivery control unit 24 in addition to the temporary mailbox 2a.
FIG. 2A is a block configuration diagram for explaining delivery control when the mail has a short message, and FIG. 2B is a block for explaining delivery control when the mail is a long message. FIG.

In FIG. 2A, the incoming call detection unit 21 detects that mail has arrived to the mail address of the client (mobile device 1b) registered in the mail system in the mobile communication network. The message determination unit 22 determines whether this message is a long message or a short message according to at least the data size of the mail message detected by the incoming call detection unit 21. When the message control unit 22 determines that the mail message detected by the incoming call detection unit 21 is a short message, the distribution control unit 24 stores the mail message in the temporary mail box 2a.
On the other hand, as shown in FIG. 2B, when the message of this mail detected by the incoming call detection unit 21 is determined to be a long message by the message determination unit 22, the message shortening unit 23 The message is shortened and stored in the temporary mail box 2a, and the mail is delivered to the mail server 3 provided with the mail box 3a having the mail address of the mail address to store the message.

FIG. 3 is an explanatory diagram for explaining conditions for determining the length of a message performed in the message determination unit 22.
(1) to (8) are determined to be long messages when the determination conditions are satisfied except for (6). For example, the message determination condition of (1) is “the total data amount of the message is XX Bytes or more”. The message determination condition in (5) is “file attached”. The message judgment condition of (6) is “multiple recipients”, and is a condition that works when the total data amount of the message is XX Bytes or less and no file is attached. Judged as a long message.
As shown in (9), when none of the conditions (1) to (8) is satisfied, it is determined that the message is a short message.

In this explanatory diagram, “size XX Bytes” is a value that can be set to a different value for each condition ((1), (2),...), And XX = 0 Bytes is also possible. .
The specific method of shortening in the message shortening unit 23 can be arbitrarily determined by the user by option designation, and the designation can be registered in the DRS 9 of FIG.
For example, it is assumed that 384 characters or 500 characters or so have been cut out from the beginning of the body of the message as conventionally transferred to SMSC8.
It is good also as a shortened message which added what extracted the header part of the message, or its part. Or it is good also considering only what cut out the header part of the message, or its part as a shortened message.

When the incoming mail is detected by the incoming call detection unit 21, the incoming call notification unit 25 notifies the incoming of the mail to the short message service center (SMSC) 8, thereby giving the destination mail address of the received mail. The client (mobile device 1b) is notified.
As already explained, the SMSC 8 simply notifies that there was an incoming call.
The incoming call notification unit 25 confirms that the short message of the received mail or the shortened message of the long message has been normally stored in the temporary mail box 2a so as to notify the incoming call. Also good. In the case of a long message, the incoming notification may be performed after confirming that the message has been normally stored in the mailbox 3a.
The same processing is performed even if the source address of the received mail is different from the mail system in the mobile communication network, for example, an arbitrary mail server 6 of an ISP belonging to a mail system on the Internet 5.

However, when it is detected that the mail is related to the destination mail address in advance and transferred from another mail address in the ISP mail server 6 by the “forwarding service”, different distribution control is performed. It is also possible.
Here, as another mail address, for example, a mail address given when a user of a client (mobile device) registered in a mail system in the mobile communication network has an account in the ISP mail server 6 as well. It is. However, other mail addresses may be registered in advance in, for example, the DRS 9 in FIG. 1 in association with the address of the client (mobile device) registered in the mail system in the mobile communication network.

When mail is forwarded and received from the ISP mail server 6 using the “forwarding service” or “incoming notification service”, the original mail message is stored in the original ISP mailbox 6a. Yes. Therefore, when forwarding, it is not necessary to store the forwarded mail message in the mail address in the mail box 3a unless the option is to delete the original mail message.
That is, a message having a short message is stored in the temporary mailbox 2a, and a message having a long message is stored in the temporary mail box 2a and stored in the mail address in the mail box 3a. You may block it.

FIG. 4 is a block diagram for explaining a case where a mobile device that has received a simple incoming notification confirms at least a part of the notified mail message.
The client (mobile device 1b) that has received a simple incoming notification from the SMSC 8 automatically sends a request for confirming the incoming content to the mail proxy server 2 in conjunction with this.
Upon receiving this request, the mail acquisition control unit 31 of the mail proxy server 2 accesses the temporary mail box 2a, and shortens the short message or the long message of the mail that is the object of simple incoming notification. The client (mobile device 1b) is made to acquire the message.
The same processing may be used whether the mail subject to notification of incoming calls originates from the mobile device 1a registered in the mail system in the mobile communication network or originates from the mail server 6 of an arbitrary ISP. .
Conventionally, it is possible to realize the same function as when at least a part of the contents of the detected mail is transmitted from the SMSC 8.
In addition, a request for confirming a part of the content of an incoming mail may be transmitted only by an operation of the user of the mobile device 1b that has received the incoming call notification.

FIG. 5 is a block diagram for explaining the message acquisition of the received mail.
A request (extended POP3 protocol) is received from the client (mobile device 1b) to obtain a mail message received to the mail address of the client.
As shown in FIG. 5A, when the mail to be acquired is a short message, the acquisition control unit 31 causes the client (mobile device 1b) to acquire the short message stored in the temporary mail box 2a.
As shown in FIG. 5 (b), when the mail to be acquired is a long message, the acquisition control means 31 accesses the mail server 3 provided with the mail box 3a and sends the stored long message to the client ( The mobile device 1b) is made to acquire.

FIG. 5 (c) shows the case where mail is transferred from the ISP mail server 6 by the ISP "forwarding service" or "incoming notification service" in an Internet mail system different from this mail system. The case where a message is acquired from the mail server 6 is shown.
If the acquired mail is a short message, the acquisition control means 31 accesses the temporary mail box 2a or the ISP mail server 6 to acquire the mail. If the acquired mail is a long message, the mail is accessed by accessing the ISP mail server 6.

In the above description, when receiving a request for acquiring a mail message from the client (mobile device 1b), the mail proxy server 2 determines whether the mail message is stored in the mail proxy server 2. For example, the storage destination is stored for each UID (Unique ID) of mail. If the mobile device 1b (client) indicates a UID (Unique ID), the storage location is known.
The mobile device 1b acquires the UID in advance by acquiring a confirmation message for the incoming call notification or by a list request command “JLIST”.

FIG. 6 is a sequence diagram for explaining processing when a long message is deleted.
A signal sequence between the client (mobile device 1b), the mail proxy server 2, and the mail server 3 is shown. The extended POP3 protocol is used between the mobile device 1b and the mail proxy server 2, and the IMAP4 protocol is used between the mail proxy server 2 and the mail server 3.
The request for deleting the message stored in the mailbox 3a only adds the “delete flag”, and the deletion of the message to the mailbox 3a is executed by the subsequent “EXPUNGE” request. On the other hand, on the mobile device 1b side, a request signal for requesting execution of deletion of the message is transmitted simultaneously with the message deletion request.
In this way, the mail proxy server 2 can execute a general-purpose IMAP4 protocol between the mail proxy server 2 and the mail server 3 while executing a unique protocol between the mobile device 1b and the mail proxy server 2. Perform protocol conversion.

A sequence after IP (Internet Protocol) connection is established between the mobile device 1b and the mail proxy server 2 will be described.
When the user of the mobile device 1b performs a message acquisition operation for the received mail stored in the mail box 3a, a plurality of procedures 41 for TCP connection between the mobile device 1b and the mail proxy server 2 are executed.
When acquiring the message, after the TCP connection is established, the “JRETR” command 42 is transmitted from the mobile device 1b. At this point, the transaction state is entered.

S-id is session ID, T-id is transaction ID, MSISDN is user ID for mail server access, MailSrvAttr is mail server attribute, imapsrvaddr is mail server address, port is mail server port number, user is user identifier or Mailbox ID, pass is the password, uid is the message unique ID, size is the maximum size of the message sent at the time of acquisition (the number of packets when 1 packet is 128 bytes), and body [section] is a specific specified This is the specification of the body section.
When the mail server 3 is designated, “*” is set in imapsrvaddr, port, user, and pass. Body structure conforms to RFC2060 of IMAP4.
Among these, UID (Unique ID) is a unique number assigned to all messages in the mailbox 3a, and is permanently distinguished from other messages in the mailbox, and conforms to RFC2060. .

The mail proxy server 2 returns a TCP (ACK) response 43. The mail proxy server 2 accesses the database (DRS) 9 having the replica of the subscriber profile, executes the procedure 44, and refers to the DRS 9 using “MSISDN” given as an argument of the “JRETR” command 42, User information (user info) of the mobile device 1b is acquired.
The mail proxy server 2 transmits a “connection socket OPEN” command 45 to the mail server 3. The mail server 3 transmits a response “* OK [CAPABILITY IMAP4 IMAP4REV1 LOGIN-REFERRALS AUTH = LOGIN]” to the mail proxy server 2. “A1” to “A6” shown below are tags, and the relationship between the command and its response is clearly indicated by the tag. “*” Indicates an untagged line.

The mail proxy server 2 transmits an “A1 LOGIN user pass” command 47 to the mail server 3. The mail server 3 transmits an “A1 OK LOGIN completed” response 48 to the mail proxy server 2. The mail proxy server 2 transmits an “A2 SELECT inbox” command 49 to the mail server 3.
The mail server 3 transmits the status information of the mailbox 3a. For example, after transmitting data such as the total number of received messages, the number of new messages, the type of message flag used, etc. stored in the user address of the mobile device 1b, “A2 OK SELECT “completed” 51 is transmitted.

Next, the mail proxy server 2 sends an “A3 UID FETCH uid BODY []” 52 command to the mail server 3. This command requests the mail server 3 for a mail message specified by uid (Unique ID). “BODY []” specifies all uid messages.
The mail server 3 transmits a mail message specified by the UID of the command 42 as a processing result, and then transmits a response completion “A3 OK FETCH completed” (completion response) 53 to the proxy server 2 in the last line.

During this time, “TCP (ACK)” 50 is returned from the mail proxy server 2 to the mobile device 1a. In order to maintain the session until the mail proxy server 2 transmits the processing result, a pseudo “TCP (ACK)” is periodically returned to the mobile device 1 a by a timer.
After receiving the received mail message, the mail proxy server 2 sends a response message 54 to the “JRETR” 42 in the order of the header part of the received mail message, the message body part, and the last message body part. Then, a response completion “+ OK <S-id><T-id><Result>” response from the mail proxy server 2 is transmitted.

Next, a case will be described in which the mobile device 1b designates the end of the session (Q) at the same time as deleting one message (D) of the mail with the UID in the mail box 3a after successfully obtaining the mail.
The mobile device 1 b transmits a “J-ACK <S-id><T-id><Result><UID> DQ” command 55 to the mail proxy server 2. On the other hand, the mail proxy server 3 returns a “TCP (ACK)” response 56 to the mobile device 1b. With this “J-ACK <S-id><T-id><Result><UID> DQ” command 55, the transaction state is terminated simultaneously with the deletion of the mail message between the mobile device 1 b and the mail proxy server 2.
Therefore, unlike the conventional procedure for waiting for the “QUIT” command from the mobile device 1b and reflecting the message deletion to the mailbox 3a, there is a disconnection of the communication line due to the radio wave condition peculiar to the radio line. Even so, the message deletion process between the mail proxy server 2 and the mail server 3 is not interrupted.
Thereafter, a plurality of sequences 63 such as a “TCP Close (FIN)” command are executed for the session termination processing of the TCP connection.

The mail proxy server 2 executes a procedure (IMAP4 protocol) for deleting the UID message in the mailbox 3a with the mail server 3, and the mail with the corresponding UID stored in the temporary mailbox 2a. The process of deleting a short message or a message with a shortened long message is performed.
In other words, the mail proxy server 2 adds a “deletion flag” to the short message or the short message of the mail with the corresponding UID stored in the temporary mail box 2a. The “A4 UID STORE uid + FLAGS.silent (\ Deleted)” command 57 is transmitted to the mail server 3. The mail server 3 adds a “delete flag” to the uid message in the mailbox 3a and returns an “A4 OK STORE completed” response 58.
The mail proxy server 2 transmits an “A5 EXPUGE” command 59 to the mail server 3. The mail server 3 physically deletes the message of the uid mail to which the “delete flag” is added, and returns a “* message number EXPUNGE” and “A5 OK EXPUNGE completed” response 60.
The mail proxy server 2 physically deletes the message of the uid mail with the “deletion flag” added in the mail box 3a. The “A6 LOGOUT” command 61 is transmitted, and the mail server 3 returns a “* BYE server logging out” and an “A6 OK LOGOUT completed” response 62.
As for the temporary mailbox 2a, the message can be physically deleted immediately when the “deletion flag” is added.

  In the above description, the “J-ACK DQ” command for ending a transaction at the same time as deleting one mail message is exemplified as the delete command in the extended POP3 protocol. In addition, a “JDELE Q” command that terminates a transaction at the same time as deleting a message by specifying multiple mails by UID, and a “JADELE Q” command that terminates a transaction at the same time as deleting all mail messages are also provided. Specifies that the transaction state is to be terminated when the argument flag flg is Q.

In the above description, the mail proxy server 2 provided with the temporary mail box 2a is assumed. However, the same problem occurs when the temporary mail box 2a is not provided.
The mail server 3 uses the IMAP4 protocol. However, even in the case of using the POP3 protocol, the transaction state is ended and the message 3 is deleted and the message is deleted only after the end command QUIT is added after the deletion flag is added by the message deletion request. There is a problem.
The above-described mail proxy server 2 can normally perform the message deletion process in the same manner as described above.

In the above description, the mail system common to the nationwide mobile communication networks has been described. However, the mail systems in each network may be combined as the mail system in each region-specific mobile communication network.
In the above description, the mail proxy server in the mail system in the mobile communication network has been described. The mail proxy server of the present invention is suitable for a mail system in a mobile communication network, but is applied to a general mail system such as a mail system on the Internet or a mail system in a wired or wireless local area network. Even in this case, similar effects can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] It is a block diagram of the mail system for describing one Embodiment of this invention. It is a block block diagram for demonstrating storage of the message of the received mail, and an incoming notification. It is explanatory drawing explaining the conditions of the message length determination performed in a message determination part. It is a block configuration diagram for explaining a case where a mobile device that has received a simple incoming notification confirms at least a part of a mail message notified. It is a block block diagram for demonstrating message acquisition of the received mail. It is a sequence diagram for demonstrating the process in the case of deleting a long message. 1 is a system configuration diagram of a mobile communication network in which a mail system is constructed. FIG. 8 is a sequence diagram for explaining processing for deleting a mail message in the mobile communication network shown in FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a, 1b ... Mobile device, 2 ... Mail proxy server, 2a ... Temporary mailbox, 3 ... Mail server, 3a ... Mail box, 5 ... Internet, 6 ... Internet service provider's mail server, 6a ... Mail box, 8 ... Short message service center, 21 ... incoming call detection unit, 22 ... message determination unit, 23 ... message shortening unit, 24 ... delivery control unit, 31 ... mail acquisition control unit

Claims (2)

When a “request signal for executing the deletion at the same time as the message deletion request” of the specified mail among the mails received to the mail address of the client is received from the client registered in the mail system, After sending a “request signal for requesting message deletion” of the specified mail to a mail server having a mailbox for storing the specified mail message, and after the mail server has responded normally, A deletion control means for causing the mail server to execute message deletion of the specified mail by transmitting a request signal for executing deletion of the requested message.
A mail proxy server device characterized by comprising: A temporary mailbox for storing a mail message received to a client mail address registered in the mail system or a message in which the mail message is shortened;
When a “request signal to execute deletion at the same time as the message deletion request” of the specified mail among the mails received to the client's mail address is received from the client, the temporary mailbox is When there is a mailbox in which the designated mail message is stored or the designated mail message is deleted and the designated mail message is stored, and there is a mailbox storing the designated mail message , A “request signal for requesting message deletion” of the specified mail is transmitted to the mail server provided with the mailbox, and after the mail server responds normally, “deletion of the message requested to be deleted” By sending a request signal to be executed ”to the mail server. Delete control means for executing the message deletion of e-mail,
A mail proxy server device characterized by comprising:

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