FR2866134A1 - Electronic mail cache memory device for e.g. personal digital assistant, has local database storing copy of mails distributed on Internet network by remote servers, and being updated according to operation mode implemented by print engine - Google Patents

Abstract

The device has a cache memory module (300) including a set of count descriptors (320) related to access to a number of electronic mails from a wireless terminal. A local database (330) storing copy of the mails distributed on an Internet network by remote servers, is updated according to an operation mode implemented by a differential print engine (310). The module has a mail identification check list and a terminal interface (340).

Description

The present invention relates to a mail cache device

  e-mail-type electronic systems particularly suitable for wireless terminals with very low energy consumption.

  The deployment of Asymmetric Digital Subscriber Line e-mail and ADSL allows everyone to communicate in writing with virtually no transmission time and to receive messages continuously, with no mail delivery time. Its joint use with the computer in a professional context thus makes it possible to obtain the same reactivity as the telephone. In the private domain, the time of use of the personal computer is less than for professional use and the benefits of e-mail type mail are reduced because in practice, a presence in front of the computer is needed to notice a mail notification. Today's computers are powerful, often noisy, so they consume a lot of energy and remain oversized as a simple mailbox. Moreover, their mobility remains debatable even for laptops, so that incoming mail can not be made known to a person since it is far from the computer, for example in his kitchen or his home. living room.

  The main object of the present invention is to overcome these drawbacks and relates to a cache memory device for electronic mail or e-mail messages, particularly suitable for wireless terminals with low energy consumption, essentially characterized in that it includes: É An Internet network access point allowing access to distant mail or e-mail servers, É A wireless local area network operating in ISM or RLAN radio bands, 25 É One or more terminals connected to said network without wire, É A cache cache module characterized in that it comprises: É A set of descriptors relating to the access to e-mail accounts that can be viewed from said terminals, É A local database of mail that can be accessed from said e-mails terminals and update according to a procedure implemented by a differential copy engine, É Ledit differential copy engine of the mails waiting on said remote servers distributed on the Internet network.

  An interface to said wireless terminals.

  It may be useful for various reasons to place in the user a local email server with which the cache device object of the invention should not be confused. US Patent 2001/0029524 A1 thus describes a device allowing the user to navigate faster on a wireless terminal between its different mailboxes. US Patent 2002/0198948 A1 allows similar functions with PDA type terminals. US Patent 2002/0059388 A1 also discloses a similar device.

  These documents describe mechanisms for downloading messages by executing their movement from a remote server to a local server placed at the user's home. From a wireless terminal, the latter then consults faster because not subject to the vagaries of Internet transmission - his messages located in his local server and no longer in the remote server. Nevertheless, this principle suffers from drawbacks: 1) The mailboxes e-mails or mailboxes tend to be interrogated according to two methods, either by a WEB World Wide Web browser such as Microsoft Internet Explorer as an ordinary HTTP HyperText Transfer Protocol site, either by a mail manager such as Microsoft Outlook. In the first case, the advantage of this method lies in the fact that the box is searchable quickly from anywhere without prior configuration. Insofar as a specific device placed in the user is responsible for automatically and periodically returning the messages, they disappear from the remote server. As a result, the remote interrogation of the user by HTTP no longer offers any interest since the mailbox will have been previously emptied of its contents by the local server.

  2) The local server is expensive because it must sometimes receive large files and must be sized for it. In addition, it must be supervised by external intervention, otherwise it will saturate.

  3) The terminals connected to the local server must be able to decode and interpret all the files attached to the messages.

  The e-mail cache device object of the present invention does not have these disadvantages. The principles implemented are now presented and an embodiment of the invention is described below by way of example, with reference to the appended drawings in which: FIG. 1 shows the general view of the cache memory device placed in its context FIG. 2 shows the detailed view of the cache memory device, FIG. 3 an example of a transaction between the remote server and the device, FIG. 4 an example of a transaction between the remote server and the device limiting the message duplication at the head of the stack. on a depth N, FIG. 5, an example of a transaction between the remote server and the device limiting the duplication of messages at the head of the stack to a depth N with use of the inhibition list, FIG. 6 shows the activity of the networks. local and wireless.

  Figure 1 gives the general view of the communication system according to the invention. According to the exemplary embodiment, a very low power consumption terminal 600 makes it possible to read on a liquid crystal display messages waiting to be read on mailboxes of the e-mail type. Attention is drawn to the fact that the terminal consumes very little energy so that its autonomy can exceed a year (similar to liquid crystal living room thermometers) and therefore its period of activity is very short compared to its sleep phase on its energy consuming functions. The state of mailboxes email must nevertheless be updated at a high rate, every five minutes for example, before being reported on the terminal. In view of what has just been said, the activity phase of this terminal must be reduced to a few milliseconds at each update, a time incompatible with an Internet transaction.

  The e-mail messages are stored in 900m ... servers, remote and connected via the 801 link to the Internet 800 network (following the protocol recommendation POP3 Post Office Protocol Version 3 described by the Internet Engineering Task Force in the document RFC1939 available on www.ietf.org) allowing messages to be downloaded to a personal computer 500 equipped with software such as Microsoft Outlook for example. The access terminal 100, disposed at the user, acts as a gateway between the ADSL interconnection link 802 to the Internet network and the local network of the user 200 usually supported by the Ethernet protocol; this network is not necessarily wired and can be wireless type RLAN Radio Local Area Network.

  The user's personal computer and the cache device 300 are connected to this local network without interaction between them and without the presence of a computer being necessary for the proper functioning of said device. It should be noted that the personal computer can also be connected to any part of the Internet so that it can read the user's messages on the mail servers 900. The cache device is connected to the other hand. terminals 600; k via a wireless network 400 in a radio band according to the legislation. For example, Industrial Scientific Medical radio bands called I.S. M. (433Mhz / 868MHz) are licensed in France as well as the frequency 2, 4Ghz wireless local area networks RLAN; other states reserved frequencies 315 and 915 MHz for the same purposes.

  Description of the cache module 300

  The cache module has the function of making e-mail messages on hold in remote servers 900 more quickly accessible by terminals 600i. k by local storage in a message database 330. The cache term advocated by the AFNOR is a translation of the Anglo-Saxon term hides generally more evocative for computer scientists. Thus, the role of the cache module is not to remove messages from remote servers but to make a copy. As a result, the messages are therefore always accessible to the user on the remote servers by its usual means, the objective of the cache module being to have the least intrusive activity possible on the network 200 and the servers 900. The engine Differential recopy 310 periodically polls remote servers according to a set of e-mail account descriptors 320 allowing authorization of access to messages.

  A descriptor is provided prior to any possible transaction between the cache module and the remote server designated by said descriptor that is acquired: Statically by the user at the initialization of the device, dynamically by the terminal 600 requesting a transaction POP3 to a remote server, the interface 340 emulating the behavior of the remote server vis-à-vis said terminal without the Internet transmission hazards.

  Said descriptor is a triplet composed of the name of the remote server (for example pop.wanadoo.fr), an e-mail account number and a password. According to a predefined periodicity, the copy engine queries each of the remote servers, provided with the connection parameters of said descriptor. The remote server considered then delivers on demand the list of available messages. At this time, the copy engine operates differentially by comparison between locally available messages and the remote server so that the local message database remains the image of the remote server. The copying of a message differs from a withdrawal in that new messages seem to appear continuously on the remote server although they have been taken into account previously since they have not been erased. The copying engine therefore quickly recognizes the already processed messages still present on the remote server in order to mark them locally as always present and naturally without copying them. The other, truly new, are copied locally in the message database 330 in full or partial form depending on the locally available memory and the service provided by the terminals 600. Finally, at the end of this process performed on an e-account. given mail, messages not always present or not really new are simply deleted from the database 330.

  The following sequence gives the chronology of the transaction between the copying engine 310 and the remote server 900: 1) Connection to the server 1) Sending of INDENTIFICATION by N of account + password 2) Sending of REQUEST of IDENTIFIERS of the messages on the remote server 15 defining a list A 3) Receipt of this list A 4) Elaboration of the list C messages to copy the server based on a list B messages already present locally.

  5) Send requests for RECOVERY messages from the C list 6) Send DECONNECTION command 7) Disconnect the server.

  8) Erasing messages from the E list.

  According to the exemplary embodiment, the server 900m is of the POP3 type and the step 1) is performed with the USER xxxx and PASS yyyy commands. The request for identifiers or message identifiers is carried out with the UIDL command. Each message has a unique identifier, that is to say a signature S, represented most often by a string of characters. The copy engine then produces a list of the differences between the list A of the server messages and that B of the local database of messages 330 by comparison between these identifiers.

  The list D = A AND B defines the messages to be kept in the local database (the logical operator AND here represents the intersection between the two sets).

  The list C = A - D defines the messages to download from the server. The new list of messages in the local database will therefore become for the next transaction B = D + C. The list E = B - D represents the messages deleted from the local database.

  The RETR xxx command is used to download a xxx message without removing it from the server. The command TOP xxxx yyyy makes it possible to read only the first yyyy lines of said message xxxx. It should be noted that the copy engine can use a hash function H (x) to obtain fixed length identifiers that are easier to manipulate, while keeping a very low probability of collision between them (in which case, two messages then have the same signature). Likewise, this same hash function can be used to sign the message by applying it to it partially, in particular on its header: S = H (beginning of the message) when the UIDL command is not available. This signature S, which is also useful for subsequent comparisons, is of course preserved with the message in the local database 330. In the absence of the UIDL and TOP commands, the length of the message accessible with the LIST command xxxx can serve as the signature S for the message xxxx. but with a significant probability of collision.

  The disconnection of the server is obtained with the command QUIT.

  FIG. 3 represents an example of a transaction according to the operating mode that has just been described, taking into account the state of the local database 330 at the time t-1 obtained during the previous transaction and that of the remote server 900 at the time moment t as it exists at the beginning of the current transaction.

  Some remote 900 mail servers offer the possibility of the WEB through an HTTP interface to leave messages already read by the user in a mailbox, hundreds of old messages can accumulate on the server together with new messages identified by the user. a different color or font. The POP3 interface has the disadvantage of not making differences between the unread messages and already read but nevertheless places the last message arrived at the head of stack. In particular, in order to mitigate this hazard, the local copy engine therefore maintains an inhibit list F 335 containing the message identifiers to be ignored and not copied for several reasons: These remain on the server but do not plus part of the stack head of the messages available on the remote server, the copy engine limiting its message loadings to a predefined depth N of this stack, these are considered to be ignored or already read by the users of the terminals 600, Eventually these are not part of the messages to be saved in the local database according to their content or their sending date as well as other options not described here.

  The list D defined above thus becomes D = (A AND B) OR F. FIG. 4 and FIG. 5 show the new behavior of the device according to the state of the battery head 901.

  Figure 6 shows on the upper timeline the activity on the network link 200 between the cache module 300 and the remote servers. The server scanning is subject to the vagaries of transmission on the Internet and are of variable length and relatively important. The lower part represents the activity on the radio link 400 caused by a transaction between a terminal and the cache module. The polling initiative of the terminal is faster to have a lower activity / sleep ratio and therefore a greater energy autonomy. They wake up and periodically request the device 300 to query the presence of messages and possibly have access to the contents thereof. The interface 340 of the cache module is in charge of serving the requests of the terminals. For this, the interface organizes the exchange of information between the local message database 330 and the radio link 400. This processing is performed with a higher priority than that of the differential copy engine so that the latency time of the answer is minimized. The cache module 300 is particularly suitable for using electronic components of the microcontroller type. Said processing is therefore supported by interrupting the microprocessor or by a high priority task of the real-time executive managing the set.

  In addition to the embodiment described above and in a more general manner, the device that is the subject of the invention offers the possibility for micro-systems or wireless and energy-saving automations to have access to mailpieces. e-mail type via the Internet mail service to configure itself and possibly return information to their sender by sending e-mail messages whose description is beyond the scope of the invention.

Claims (10)

  1. Email caching device of e-mail type, particularly suitable for wireless terminals with low energy consumption, essentially characterized in that it comprises: É An access point (100) to the Internet network ( 800) to reach remote mail or e-mail servers (900m n), É A local area network (200), É A wireless local area network (400) operating in the so-called ISM or RLAN radio bands, E One or more terminals (600, k) connected to said wireless network, É A cache module (300) of electronic mails characterized in that it comprises: É A set (320) of account descriptors relating to access to email accounts which can be viewed from said terminals, É A local database (330) of mails that can be viewed from said terminals and updated according to a procedure implemented by a differential copy copying engine, É Le said engine for recopy (310) differential mail waiting on said remote servers distributed on the Internet.   É An inhibition list (335) of mail identifiers, É An interface (340) to said wireless terminals.   2. Device according to claim 1, characterized in that for a given e-mail account, said copy engine performs the transfer of mail from a remote server (900;) to said local database without erasing said server, 3. Device according to claims 1 and 2, characterized in that said copy engine is periodically activated, 4. Device according to claims 1 to 3, characterized in that said copy engine only performs the transfer of said observed mail absent from said local database and removes the observed missing mails from the remote server in the same local database so that the latter represents a copy of the remote server, 5. Device according to claims 1 to 4, characterized in that said copy engine performs a comparison of the mails contained in said server and said base according to identifiers representative of said mails in a one-time and invariable manner, 6. Device according to claims 1 to 5, characterized in that said identifiers are provided directly by the remote server or by a hash function applied by said differential copy engine to an attribute or content of said mails, 7. Device according to claims 1 to 6, characterized in that said copying engine only considers the mail head stack and last arrived on the remote server to a predefined depth, 8. Device according to claims 1 to 7, characterized in that said copy engine does not transfer mail whose identifiers are contained in a list of inhibition (335) representative of mail still present on the server and having been previously copied in the local base but no longer part of said stack head.   9. Device according to claims 1 to 8, characterized in that said inhibition list 20 also contains the mail identifiers discarded at the request of said terminals, 10. Device according to claims 1 to 9, characterized in that said account descriptors are acquired statically at the initialization of the system or dynamically according to requests for access to remote servers issued by said terminals.