JP2004254038A - Mail communication relay system, mail communication relay apparatus, mail communication relay method, and mail communication relay program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mail communication relay system, a mail communication relay apparatus, a mail communication relay method and a mail communication relay program which can reduce delay in electronic mail communication without changing existing mail servers and mail clients. <P>SOLUTION: When the mail server 400 transmits a message of electronic mail to the mail client 100, a client proxy 200 and a server proxy 300 use pipelining to carry out electronic mail communication via a network 10 with each other. On the other hand, the mail client 100 and the mail server 400 respectively carry out electronic mail communication according to the conventional POP3 (post office protocol version 3) protocol not employing the pipelining. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mail communication relay system for relaying electronic mail communication between a mail server and a mail client, a mail communication relay device, a mail communication relay method, and an electronic mail communication method between a mail server and a mail client. The present invention relates to a mail communication relay program executed on a relaying computer.
[0002]
[Prior art]
RFC (Request For Comments) 1939 (for example, see Non-Patent Document 1) as a protocol used when a mail client operating on a user terminal downloads an electronic mail message addressed to the user stored in a mail server. ), POP3 (Post Office Protocol version 3) is widely used. When downloading a message based on the POP3 protocol, the mail client transmits a command (message request command) requesting one message to the mail server. When receiving the message request command, the mail server transmits one corresponding message to the mail client. When messages addressed to a plurality of users are stored in the mail server, the mail client cannot send the next message request command until one message corresponding to the message request command is received. The transmission of the message request command and the transmission of the message by the mail server are repeated.
[0003]
That is, when acquiring a plurality of messages, the mail client transmits a message request command to acquire one message, and after receiving one message transmitted by the mail server in response to the message request command, Send a message request command to get the next message.
[0004]
However, in such a procedure of waiting for the mail client to receive one message and transmitting the message request command to acquire the next message, one RTT (Round Trip) is performed every time one message is received. (Time: network round trip time). For this reason, when there is a network such as a wireless network between the mail client and the mail server where delay is likely to be large, there is a problem that it takes much time for the mail client to receive all the messages (FIG. 1). reference).
[0005]
In order to reduce such a delay in e-mail communication, RFC2449 (for example, see Non-Patent Document 2) standardizes a method of e-mail communication called “pipelining”. In pipelining, the mail client can make a request to send the next message even before receiving a message from the mail server in response to the message request command. This can reduce the delay when the mail client receives a plurality of messages (see FIG. 2).
[0006]
[Non-patent document 1]
Myers, J, "Post Office Protocol-Version 3, STD53, RFC 1939", May 1996.
[0007]
[Non-patent document 2]
Gellens, R, "POP3 Extension Mechanism, RFC2449," November 1998.
[0008]
[Problems to be solved by the invention]
However, in order to enable e-mail communication using pipelining, it is necessary to change existing mail servers and mail clients that do not support pipelining.
[0009]
The present invention has been made to solve the above problems, and an object thereof is to provide a mail communication relay system capable of reducing a delay in e-mail communication without changing existing mail servers and mail clients, and a mail. A communication relay device, a mail communication relay method, and a mail communication relay program are provided.
[0010]
[Means for Solving the Problems]
To achieve the above object, according to the present invention, a first mail communication relay device functioning as a proxy for a mail client and a second mail communication relay functioning as a proxy for a mail server are provided. A mail communication relay system that relays electronic mail communication between the mail server and the mail client, wherein the first mail communication relay device is provided with respect to the second mail communication relay device. A first message requesting unit that transmits requests for a plurality of messages at once, wherein the second mail communication relay device responds to a plurality of message requests from the first mail communication relay device, Second message requesting means for requesting a message to a mail server; and the mail in response to a request by the second message requesting means. First message transmitting means for transmitting a plurality of messages transmitted from the server to the first mail communication relay device at a time, wherein the first mail communication relay device Message storage means for storing a plurality of messages transmitted collectively from the communication relay device, and, when a message request is received from the mail client, extracting a message corresponding to the message request from the message storage means; And a second message transmitting means for transmitting to the mail client.
[0011]
According to the present invention, the first mail communication relay device functioning as a proxy of the mail client transmits a request for a plurality of messages at once, and the second mail communication relay device functioning as a proxy of the mail server transmits the message request. To send multiple messages at once. That is, the first mail communication relay device functioning as a proxy of a mail client and the second mail communication relay device functioning as a proxy of a mail server mutually perform e-mail communication using pipelining, and the existing mail is exchanged. It is possible to reduce the delay of e-mail communication in the network between the first mail communication relay device and the second mail communication relay device without changing the server and the mail client.
[0012]
According to a second aspect of the present invention, in the mail communication relay system according to the first aspect, the first message request unit acquires a message list from the second mail communication relay device. Then, a request for a plurality of messages is transmitted collectively based on the message list.
[0013]
As described above, the first mail communication relay device functioning as a proxy of the mail client obtains the message list, and thereby, the message to be requested to the second mail communication relay device functioning as the mail server proxy is obtained. Can be recognized.
[0014]
Further, from the same viewpoint as the invention described in claim 1, the present invention provides a mail system having a mail client and a mail server, wherein the mail functioning as a proxy for the mail client is provided in a mail system having a mail client and a mail server. In the communication relay device, a message request unit that collectively transmits a request for a plurality of messages to the mail server or another mail communication relay device that functions as a proxy of the mail server, and responds to the request by the message request unit. A message storage unit for storing a plurality of messages transmitted collectively from the mail server or another mail communication relay device functioning as a proxy for the mail server; and a message request from the mail client. , A message corresponding to the message request is stored in the message storage Removed from, characterized in that it comprises a message transmission means for transmitting to the mail client.
[0015]
In addition, from the same viewpoint as the invention described in claim 2, the present invention as described in claim 4, in the mail communication relay device according to claim 3, wherein the message requesting unit is configured so that: A message list is obtained from another mail communication relay device functioning as a proxy for the mail server, and requests for a plurality of messages are transmitted collectively based on the message list.
[0016]
Further, from the same viewpoint as the invention described in claim 1, the present invention provides a mail system having a mail client and a mail server, wherein the mail functioning as a proxy for the mail server is provided in a mail system having a mail client and a mail server. In the communication relay device, message request means for requesting a message to the mail server in response to a request for a plurality of messages from the mail client or another mail communication relay device functioning as a proxy for the mail client, and the message request Means for transmitting a plurality of messages transmitted from the mail server in response to a message request by the means to the mail client or another mail communication relay device functioning as a proxy for the mail client. It is characterized by the following.
[0017]
Further, from the same viewpoint as the invention described in claim 1, the present invention provides a mail system having a mail client and a mail server, wherein the mail server and the mail client are connected to each other. In a mail communication relay method for relaying electronic mail communication between, a step of collectively transmitting a request for a plurality of messages to the mail server or another mail communication relay device functioning as a proxy for the mail server, Storing, in a storage device, a plurality of messages collectively transmitted from the mail server or another mail communication relay device functioning as a proxy for the mail server in response to a request for the plurality of messages, and When there is a message request from the above, the message corresponding to the message request is described above. Removed from the apparatus, characterized by comprising a step of transmitting to the mail client.
[0018]
Further, from the same viewpoint as the invention described in claim 1, the present invention provides a mail system having a mail client and a mail server, wherein the mail server and the mail client are connected to each other. In the mail communication relay method for relaying electronic mail communication between the mail client, in response to a request for a plurality of messages from the mail client or another mail communication relay device functioning as a proxy of the mail client, a message request to the mail server And a step of collectively transmitting a plurality of messages transmitted from the mail server in response to the message request to the mail client or another mail communication relay device functioning as a proxy for the mail client. It is characterized by having.
[0019]
Further, from the same viewpoint as the invention described in claim 1, the present invention provides a mail processing executed by a computer that relays electronic mail communication between a mail server and a mail client as described in claim 8. A program for transmitting a request for a plurality of messages collectively to the computer, the mail server or another computer functioning as a proxy for the mail server, in response to the request for the plurality of messages; Storing a plurality of messages collectively transmitted from the mail server or another computer functioning as a proxy of the mail server in a storage device, and when a message request is received from the mail client, Retrieving a message corresponding to the message request from the storage device, Characterized in that to execute a step of transmitting to the Lumpur client.
[0020]
In addition, from the same viewpoint as the invention described in claim 1, the present invention provides a mail server that is executed by a computer that relays electronic mail communication between a mail server and a mail client. A program for requesting a message to the mail server in response to a request for a plurality of messages from the mail client or another computer functioning as a proxy for the mail client; Transmitting a plurality of messages transmitted from the mail server in response to the request to the mail client or another computer functioning as a proxy for the mail client.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 3 is a diagram showing a configuration example of the electronic mail communication system according to the embodiment of the present invention. An e-mail communication system 1 shown in FIG. 1 includes a mail client 100 that receives an e-mail, and a client proxy that functions as a proxy for the mail client 100 and relays e-mail communication between the mail client 100 and the network 10. 200, a mail server 400 that transmits e-mail to the mail client 100, and a server proxy 300 that functions as a proxy for the mail server 400 and relays e-mail communication between the mail server 400 and the network 10. Is provided.
[0023]
In the electronic mail communication system 1, the mail client 100 and the mail server 400 are clients and servers that do not perform electronic mail communication by pipelining.
[0024]
Further, a mail relay system is configured by the client proxy 200 and the server proxy 300. The client proxy 200 may be mounted on an independent device, or may be mounted on the same device as the mail client 100. Similarly, the server proxy 300 may be mounted on an independent device, or may be mounted on the same device as the mail server 400. The network 10 is a network having a large delay, such as a wireless network.
[0025]
The mail client 100 has POP3 mail client software installed and receives an e-mail based on the POP3 protocol. On the other hand, the mail server 400 has POP3 mail server software installed, and transmits an e-mail based on the POP3 protocol.
[0026]
The client proxy 200 is connected to the message request command generator 210, the relay control circuit 220, the message cache 230, the mail client terminal 240 connected to the mail client 100, and the server proxy 300 via the network 10. And a server proxy side terminal 250.
[0027]
The message request command generation unit 210 obtains a message list indicating a list of e-mail messages addressed to a user (hereinafter, simply referred to as a “user”) of the device in which the mail client 100 is mounted from the mail server 400. I do. Further, the message request command generator 210 generates a command (message request command) for requesting an electronic mail message addressed to the user based on the message list.
[0028]
The relay control circuit 220 is connected to the message request command generator 210, the message cache 230, the mail client terminal 240, and the server proxy terminal 250. The relay control circuit 220 relays various types of information exchanged among the message request command generator 210, the message cache 230, the mail client side terminal 240, and the server proxy side terminal 250 according to the type.
[0029]
The message cache 230 stores an e-mail message transmitted from the mail server 400.
[0030]
The server proxy 300 includes a relay control circuit 310, a command queue 320, a client proxy side terminal 330 connected to the client proxy 200 via the network 10, and a mail server side terminal 350 connected to the mail server 400. .
[0031]
The relay control circuit 310 is connected to the command queue 320, the client proxy side terminal 330, and the mail server side terminal 350. The relay control circuit 310 relays various types of information exchanged between the command queue 320, the client proxy side terminal 330, and the mail server side terminal 350 according to the type.
[0032]
The command queue 320 stores, under the control of the relay control circuit 310, commands arriving at the client proxy terminal 330 in the order of arrival. The command queue 320 sends out the stored commands to the mail server side terminal 350 in the order of arrival under the control of the relay control circuit 310.
[0033]
Next, the operation of the electronic mail communication system 1 when transmitting an electronic mail message from the mail server 400 to the mail client 100 will be described with reference to the sequence diagram of FIG.
[0034]
The mail client 100 first establishes a connection with the client proxy 200. The client proxy 200 establishes a connection with the server proxy 300 according to the connection from the mail client 100. Further, the server proxy 300 establishes a connection with the mail server 400 according to the connection from the client proxy 200. Through such a procedure, a connection between the mail client 100 and the mail server 400 is established (step 101).
[0035]
Next, the mail client 100 transmits the user name and password for authentication given to the user to the client proxy 200. When the relay control circuit 220 in the client proxy 200 recognizes that the information arriving at the mail client terminal 240 is a user name and a password, the relay control circuit 220 passes these user names and passwords through the server proxy terminal 250 and the network 10. Send to server proxy 300.
[0036]
When the relay control circuit 310 in the server proxy 300 recognizes that the information arriving at the client proxy terminal 330 is a user name and a password, the relay control circuit 310 transmits the user name and password to the mail server 400 via the mail server side terminal 350. Send to Upon receiving the user name and the password, the mail server 400 authenticates the user with the user name and the password (step 102).
[0037]
Next, the mail client 100 transmits a command (message list request command) for requesting a message list showing a message list to the client proxy 200 in order to confirm the presence or absence of a message addressed to the user. When the relay control circuit 220 in the client proxy 200 recognizes that the information arriving at the mail client terminal 240 is a message list request command, the relay control circuit 220 transmits this message list request command via the server proxy terminal 250 and the network 10. Send to server proxy 300.
[0038]
When the relay control circuit 310 in the server proxy 300 recognizes that the information arriving at the client proxy terminal 330 is a message list request command, the relay control circuit 310 transmits this message list request command to the mail server 400 via the mail server side terminal 350. (Step 103).
[0039]
The mail server 400 that has received the message list request command transmits a message list indicating a list of messages addressed to the user to the server proxy 300. When the relay control circuit 310 in the server proxy 300 recognizes that the information arriving at the mail server terminal 350 is a message list, the relay control circuit 310 transmits the message list to the client proxy 200 via the client proxy terminal 330 and the network 10. Send.
[0040]
When the relay control circuit 220 in the client proxy 200 recognizes that the information arriving at the server proxy terminal 250 is a message list, it transmits this message list to the mail client 100 via the mail client terminal 240 ( Step 104).
[0041]
The relay control circuit 220 in the client proxy 200 sends the received message list to the message request command generator 210. The message request command generator 210 generates a message request command for each message addressed to one user in order to request all messages addressed to the user indicated in the received message list, and Send to 220 (step 105). The relay control circuit 220 collectively transmits these message request commands to the server proxy 300 via the server proxy side terminal 250 and the network 10 (step 106).
[0042]
When the relay control circuit 310 in the server proxy 300 recognizes that the information arriving at the client proxy terminal 330 is a message request command, it sends these message request commands to the command queue 320 in the order of arrival. The command queue 320 stores the message request commands in the order of arrival. Further, the relay control circuit 310 extracts the first message request command that has arrived from the message request commands stored in the command queue 320, and transmits the message request command to the mail server 400 via the mail server terminal 350 (step 107). .
[0043]
When receiving the message request command, mail server 400 transmits a message corresponding to the message request command to server proxy 300 (step 108).
[0044]
When recognizing that the information arriving at the mail server terminal 350 is a message, the relay control circuit 310 in the server proxy 300 determines whether a message request command remains in the command queue 320. When the message request command remains in the command queue 320, the relay control circuit 310 takes out the next message request command from the command queue 320 and sends it to the mail server 400 via the mail server terminal 350. This operation of the server proxy 300 is repeated until there is no more message request command in the command queue 320 (steps 109 and 111). Each time the mail server 400 receives a message request command from the server proxy 300, it sends a message corresponding to the message request command to the server proxy 300 (steps 110 and 112).
[0045]
Further, each time a message arrives at the mail server terminal 350, the relay control circuit 310 in the server proxy 300 transmits the message to the client proxy 200 via the client proxy terminal 330 and the network 10.
[0046]
When the relay control circuit 220 in the client proxy 200 recognizes that the information arriving at the server proxy terminal 250 is a message, it sends the message to the message cache 230 every time the message arrives. The message cache 230 sequentially stores the messages from the relay control circuit 220 (steps 113, 114, 115).
[0047]
On the other hand, the user recognizes the contents of the message list transmitted to the mail client 100 in step 104, and requests the mail client 100 for a desired message. The mail client 100 transmits a message request command for requesting one message to the client proxy 200 in response to the request of the user (step 116).
[0048]
When the relay control circuit 220 in the client proxy 200 recognizes that the information arriving at the mail client terminal 240 is a message request command, it extracts the message corresponding to the message request command from the message cache 230, and The message is transmitted to the mail client 100 via the server 240 (step 117).
[0049]
Each time the mail client 100 receives a message, the mail client 100 determines whether or not the user has further requested the message. If the user has further requested a message, the mail client 100 transmits a message request command for requesting one message to the client proxy 200 in response to the user's request (step 118, 120).
[0050]
Each time a message request command arrives at the mail client terminal 240, the relay control circuit 220 in the client proxy 200 retrieves a message corresponding to the message request command from the message cache 230, and sends the mail to the mail client terminal 240 via the mail client terminal 240. The message is transmitted to the client 100 (steps 119 and 121).
[0051]
As described above, in the email communication system 1 of the present embodiment, when an email message is transmitted from the mail server 400 to the mail client 100, the client proxy 200 and the server proxy 300 communicate with each other using pipelining. E-mail communication via the network 10 is performed. On the other hand, the mail client 100 and the mail server 400 each perform e-mail communication using the conventional POP3 protocol without using pipelining. Therefore, it is possible to reduce delay in e-mail communication via the network 10 having a large delay, such as a wireless network, without making a change to adopt pipelining in the existing mail server 400 and mail client 100. Can also make efficient use of the network 10.
[0052]
In addition, the client proxy 200 acquires a message list indicating a list of e-mail messages addressed to the user from the mail server 400. A message request command can be generated.
[0053]
In the above-described embodiment, both the mail client 100 and the mail server 400 perform e-mail communication using the conventional POP3 protocol without using pipelining. However, one of the mail client 100 and the mail server 400 performs pipelining. The present invention can also be applied to a case where electronic mail communication is performed by using.
[0054]
Specifically, if the mail client 100 performs e-mail communication using pipelining, the e-mail communication system 1 does not need to include the client proxy 200. In this case, the mail client 100 and the server proxy 300 perform e-mail communication with each other via the network 10 using pipelining.
[0055]
In addition, if the mail server 400 performs e-mail communication using pipelining, the e-mail communication system 1 does not need to include the server proxy 300. In this case, the client proxy 200 and the mail server 400 perform e-mail communication with each other via the network 10 using pipelining.
[0056]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce delays in e-mail communication without changing existing mail servers and mail clients.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a conventional e-mail communication using a POP3 protocol.
FIG. 2 is a diagram illustrating an example of electronic mail communication using conventional pipelining.
FIG. 3 is a diagram illustrating a configuration example of an electronic mail communication system according to the embodiment;
FIG. 4 is a sequence diagram showing an operation of the electronic mail communication system of the embodiment.
[Explanation of symbols]
1 E-mail communication system
10 Network
100 mail client
200 client proxy
210 Message request command generator
220, 310 relay control circuit
230 Message Cache
240 mail client terminal
250 server proxy side terminal
300 server proxy
320 Command Queue
330 Client proxy terminal
350 Mail server side terminal
400 mail server

Claims (9)

It has a first mail communication relay device functioning as a proxy for a mail client, and a second mail communication relay device functioning as a proxy for a mail server, and is used for electronic mail communication between the mail server and the mail client. In a mail communication relay system that relays,
The first mail communication relay device,
A first message requesting unit that collectively transmits a request for a plurality of messages to the second mail communication relay device;
The second mail communication relay device,
Second message requesting means for requesting a message to the mail server in response to a request for a plurality of messages from the first mail communication relay device;
First message transmitting means for collectively transmitting a plurality of messages transmitted from the mail server in response to a request by the second message requesting means to the first mail communication relay device;
With
The first mail communication relay device,
Message storage means for storing a plurality of messages collectively transmitted from the second mail communication relay device;
A second message transmitting unit that, when a message request is received from the mail client, retrieves a message corresponding to the message request from the message storage unit and transmits the message to the mail client;
A mail communication relay system comprising: The mail communication relay system according to claim 1,
The first message requesting means obtains a message list from the second mail communication relay device, and transmits a plurality of message requests collectively based on the message list. Communication relay system. In a mail system having a mail client and a mail server, in a mail communication relay device functioning as a proxy for the mail client,
Message request means for collectively transmitting requests for a plurality of messages to the mail server or another mail communication relay device functioning as a proxy for the mail server,
Message storage means for storing a plurality of messages transmitted collectively from the mail server or another mail communication relay device functioning as a proxy for the mail server, in response to a request by the message request means,
When there is a message request from the mail client, a message transmitting unit that retrieves a message corresponding to the message request from the message storage unit and transmits the message to the mail client;
A mail communication relay device comprising: The mail communication relay device according to claim 3,
The message requesting unit obtains a list of messages from the mail server or another mail communication relay device functioning as a proxy for the mail server, and transmits a request for a plurality of messages collectively based on the list of messages. A mail communication relay device. In a mail system having a mail client and a mail server, in a mail communication relay device functioning as a proxy for the mail server,
Message request means for requesting a message to the mail server in response to a request for a plurality of messages from the mail client or another mail communication relay device functioning as a proxy for the mail client,
A message transmitting unit that collectively transmits a plurality of messages transmitted from the mail server in response to a message request by the message requesting unit to the mail client or another mail communication relay device that functions as a proxy for the mail client. When,
A mail communication relay device comprising: A mail communication relay method for relaying electronic mail communication between the mail server and the mail client in a mail system having a mail client and a mail server,
A step of collectively transmitting requests for a plurality of messages to the mail server or another mail communication relay device functioning as a proxy for the mail server,
A step of storing, in a storage device, a plurality of messages transmitted collectively from the mail server or another mail communication relay device functioning as a proxy for the mail server in response to the request for the plurality of messages,
When a message request from the mail client is received, a message corresponding to the message request is retrieved from the storage device, and transmitted to the mail client;
A mail communication relay method comprising: A mail communication relay method for relaying electronic mail communication between the mail server and the mail client in a mail system having a mail client and a mail server,
In response to a request for a plurality of messages from the mail client or another mail communication relay device that functions as a proxy for the mail client, a procedure for requesting a message to the mail server,
A step of collectively transmitting a plurality of messages transmitted from the mail server in response to the message request to the mail client or another mail communication relay device functioning as a proxy of the mail client;
A mail communication relay method comprising: In a mail communication relay program executed on a computer that relays electronic mail communication between a mail server and a mail client,
To the computer,
A step of collectively transmitting a plurality of message requests to the mail server or another computer functioning as a proxy for the mail server,
A step of storing, in a storage device, a plurality of messages collectively transmitted from the mail server or another computer functioning as a proxy for the mail server in response to the request for the plurality of messages,
When a message request from the mail client is received, a message corresponding to the message request is retrieved from the storage device, and transmitted to the mail client;
A mail relay program that executes In a mail communication relay program executed on a computer that relays electronic mail communication between a mail server and a mail client,
To the computer,
In response to a request for a plurality of messages from the mail client or another computer functioning as a proxy for the mail client, a procedure for requesting a message to the mail server,
A step of transmitting a plurality of messages transmitted from the mail server in response to the request for the message to the mail client or another computer functioning as a proxy of the mail client in a lump;
A mail relay program that executes

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