EP2912849A1

EP2912849A1 - Method for the recovery of content corresponding to a url address by a client device

Info

Publication number: EP2912849A1
Application number: EP13783276.2A
Authority: EP
Inventors: Daniele Vito Finocchiaro; Antonio Arcidiacono
Original assignee: Eutelsat SA
Current assignee: Eutelsat SA
Priority date: 2012-10-26
Filing date: 2013-10-16
Publication date: 2015-09-02
Also published as: CA2889329A1; FR2997598A1; WO2014063971A1; MX2015005213A; US20150295987A1; FR2997598B1; MX353184B; US10523734B2; BR112015009293A2; RU2015119609A

Abstract

The invention relates to a method for the recovery of content such as an HTML page corresponding to a URL address by a client device, comprising the following steps: on the basis of a URL address corresponding to the content, the client device checks for the presence of the content of the URL address in a cache memory of the client device; in the absence of the content of the URL address in the cache memory, the client device creates a short message including the URL address; the message is transmitted by the client device to a server device according to a one-way transmission protocol without a given connection; the server device downloads the content corresponding to the URL address onto the internet network; the content is transmitted to the client device by the server device via a one-way protocol with coding and without acknowledgement; the content is received by the client device; and the content is recovered and stored by the client device in the memory cache.

Description

Method for recovering content corresponding to an address

URL by a client device

The present invention relates to a method of retrieving content such as an HTML page corresponding to a URL address by a client device. The method according to the invention finds a particularly advantageous application in the case of a satellite signal receiving installation having a very efficient forward path (high bit rate) and a very limited return path (low bit rate ).

At present, the broadcasting of digital television programs by satellite (for example according to one of the DVB-S, DVB-S2 or DVB-SH standards) is widely used throughout the world. Many devices are installed in millions of users. The devices installed are mainly reception devices which comprise an outdoor unit including a parabolic reflector which focuses the modulated microwave signals, on the source, called horn, of an LNB (of the English "Low Noise Block") and which translates by receiving block), the LNB transforming the received microwave signals into electrical signals in an intermediate satellite band in order to transmit them via a coaxial cable to the STB satellite decoder. The decoder includes a demodulation block (DVB-S, DVB-S2 or DVB-SH) which extracts a modulated signal "useful" in the modulated signal transmitted on the coaxial cable and demodulates the extracted "useful" signal. The demodulated "useful" signal may, for example, be used for displaying video images on a television screen.

The offers for broadcasting digital television programs by satellite are today essentially purely passive, that is to say unidirectional ("one-way service" in English).

However, it may be useful to be able to offer services requiring a limited-rate return channel; this is the case, for example, of interactive services (voting, consumption of conditional access content by key exchange, orders for new services such as video on demand). In addition, this return path can find particularly interesting applications in the field of machine communications. machine (machine to machine) or M2M to control certain devices (alarm, heating, ...) and / or recover data measured by sensors or meters (gas, electricity ...) present within the homes.

A known solution to this problem is to use a return channel using an ADSL type of connection provided by fixed telephony operators (PSTN or "Switched Telephone Network") or a GPRS / UMTS type connection provided by mobile operators. This solution therefore requires additional hardware and an additional subscription; Moreover, the telephone switching is not particularly suitable for the transmission of small messages such as voting or command messages (relatively high cost, network saturation problems ...). In addition, the territorial coverage of these terrestrial networks is limited.

Another alternative is to use high speed bi-directional satellite terminals, but the cost of equipment and subscription may be too high for an application that uses only a very low transmission rate.

Most satellite TV offers do not include return lanes. An example of a bidirectional satellite television broadcasting system described in patent document EP0888690 can be cited; this system uses a Ku-band wideband and a narrow-band return channel L. This system is cumbersome, complex and expensive in that it requires the presence of two reflectors (for each Ku and L band) or a dedicated reflector comprising a reflector adapted to receive Ku-band signals and incorporating an L-band transmission antenna. This system also entails the presence of two physical data-transmission channels, one of the Ku-band antenna towards the decoder inside the house and the other from the decoder to the antenna in L-band. It is easy to understand that this type of installation entails a complete change in the standard systems currently fitted to the fireplaces and a significant additional cost. Another example of bidirectional satellite television broadcasting system is described in the patent application WO201 1076791 filed by the applicant. This system uses a Ku or Ka broadband one-way channel and a narrow band S or C-band return channel, the signals being multiplexed on the same coaxial cable. The gain of the reflector for receiving Ku or Ka-band microwave signals is used to transmit the back-channel signals in the S-band or the C-band.

In the situations mentioned above, the return channel is a very narrow band return channel with a reduced bit rate. It is therefore understandable that the use of such a return channel is today limited to applications such as interactive services and does not allow access to the Internet, including browsing the Web. Normal Internet access is indeed based on the TCP / IP protocol; the latter requires a certain level of bit rate and limited latency for the return channel so as to ensure the sending of acknowledgments specific to this protocol. Therefore, such a protocol works very difficult with a return channel limited in speed and with a high latency (for example greater than 1 s).

A known solution to this problem in the case of satellite networks is to use TCP accelerators in order to improve TCP / IP performance over a link with high latency. The accelerator attempts to reduce the number of acknowledgments without deleting all acknowledgments. The accelerator does not further eliminate connection establishment requests with the use of a SYN synchronization flag. Consequently, even in the presence of a TCP accelerator, the strong imbalance between a forward and a return channel makes it very difficult to use the TCP / IP protocol which requires many round trips by sending requests and acknowledgments and therefore an intensive use of the non-adapted return path.

In this context, the present invention aims at providing a method for retrieving content such as an HTML page corresponding to a URL address by a client device in a system having a high-performance go channel and a return channel. reduced in terms of bit rate. To this end, the invention proposes a method of recovering content in the form of an HTML page corresponding to a URL address by a client device comprising the following steps:

- from a URL address corresponding to said content, verification by the client device of the presence of the content of the URL address in a memory of the client device;

in the absence of the content of the URL address in the memory, creation by the client device of a short message including the URL address;

transmission of said message by the client device to a server device according to a given unidirectional transmission protocol without a given connection;

downloading on the Internet network by the server device the content corresponding to said URL address;

- Analysis of said content by the server device and downloading on the Internet network by the server device elements such as images and scripts whose link is contained in said content;

- Creation by the server device of a single file incorporating said content and the previously downloaded elements;

transmission of said content as well as elements previously downloaded by the server device to the client device in the form of said single file via a unidirectional protocol with coding without acknowledgment;

receiving said single file by the client device;

recovering and storing by the client device of said single file in said memory.

Thanks to the invention, a client device and a server device located respectively at a user terminal and at a land station are advantageously used. The client device sends a request corresponding to a request for access to content such as a web page associated with a URL. This request is made in the form of a single short message using, for example, a modulation technique based on a spread spectrum protocol such as an asynchronous protocol. SPREAD ALOHA type bandwidth multiple random access (such a protocol is described, for example, in ETSI TS 102 721 -3). This short message can also be sent via SMS ("Short Message Service") using a terrestrial cellular network.

Generally speaking, sending a short message means using a technology that can send a limited number of messages per day, each with less than 2000 bytes per message, with high latency, and without prior establishment. a "connection" (for example via the exchange of a "handshake"), the transmission duration of a message being less than or equal to 1 s.

According to a preferred embodiment of the invention, the short message including the URL address comprises only one or more packets of the layer 2 "data link" of the OSI model. Thus, when the client device sends said message, it does not specify a recipient address. This preferred embodiment of the invention is particularly interesting in the case of a satellite communication between the client device and the server device. The short message may advantageously comprise only one packet of the layer 2 "data link".

According to another embodiment of the invention, the sending of the short message including the URL address by the client device to the server device may be in accordance with the User Datagram Protocol (UDP).

The server device receives the URL address and will act as a proxy server by finding the content (ie the web page) associated with the URL address on the Internet. Once the content is retrieved (as well as, where appropriate, the images and scripts whose link is contained in the page, which are necessary for display), the server device transmits to the client device a file incorporating the content in the form a single sending using a unidirectional protocol with coding without acknowledgment such as one of the protocols used for the technology "push" (also called "datacast"). The client device will store the content and act as a proxy-cache to the user. The user communicates directly via his user terminal with the client device using his internet browser: the user has the "impression" of surfing the internet using the TCP / IP protocol.

Note that the client device is preferably integrated with a device operating in transmission and reception both capable of transmitting short messages (object of the invention) but also of receiving modulated (for example, satellite) signals such as TV signals. In this case, the client device integrates a demodulator enabling the demodulation of the signals received in the forward channel by satellite operating for example according to the DVB-S2 standard (ETSI EN 302 307 v1.2.1 Digital Video Broadcasting (DVB); channel coding and modulation Systems for Broadcasting, Interactive Services, News Gathe- ring and other broadband satellite applications) and a modulator for the creation of short messages (for example a modulator operating according to an asynchronous protocol with multiple random access according to the standard described in ETSI TS 102 721 -3: "Satellite Earth Stations and Systems: Air Interface for S-Band Mobile Interactive Multimedia (S-MIM); Part 3: Physical Layer Specification, Return Link Asynchronous Access.")

The process according to the invention may also have one or more of the following characteristics, considered individually or in any technically possible combination:

the method according to the invention comprises a step of extraction by the client device from said single file of the content as well as previously downloaded elements whose link is contained in said content, storage of said content and said previously downloaded elements in the memory of the client device, and making available to a user terminal said content and said previously downloaded elements;

the method according to the invention comprises a step of creation by the server device of a single file incorporating said content, said content being transmitted in the form of said file by the server device to the client device via said unidirectional protocol with coding without acknowledgment ; the method according to the invention comprises a step of verification by the server device of the presence of the content of the URL address in a memory of the server device so that said downloading on the Internet network by the server device of the content corresponding to said address URL is in the absence of the contents of the URL in the memory;

the content is an HTML page, said method comprising the step of analyzing said content by the server device and, where appropriate, downloading on the Internet network by the server device elements such as images and scripts whose link is contained in said content; in other words, if the URL corresponds to a web page, the server device will download on the Internet the content referenced by the HTML code (images, Javascript script, ...); said server device sends said elements asynchronously, said client device being ready to receive said elements and to store them in its memory;

the method according to the invention comprises the following steps:

o attempt to open the link associated with the URL address on the browser of a user terminal;

o transmitting a DNS request from said user terminal to the client device;

o verification by the client device of the presence of the server name associated with the DNS query in a local database of the client device; o if the server name is present in said database, transmission by the client device to the user terminal of the IP address already associated with said server name;

o if the server name is not present in said database, creation by the client device of a temporary IP address associated with said server name and transmission by the client device to said user terminal of said temporary IP address and recording of said temporary IP address in said database;

o Attempting to establish a TCP connection by the user terminal with the server corresponding to said temporary IP address, said client device replacing the server by assigning itself said temporary IP address so that the TCP connection is established between the terminal user and the client device;

o transmission of an HTTP request including the URL address by the user terminal to the client device, receipt of the URL address by the client device resulting in said step of verification by said client device of the presence of the content of said URL address in a memory of the client device; o recovery of the content by the client device and sending the content to the user terminal through the established TCP connection, said unidirectional protocol with coding without acknowledgment is one of the protocols used for the "push" technology also known as "data-cast";

said transmission of the message by the client device to the server device is performed by a satellite transmission, said method comprising the following steps:

o uplink transmission by the client device of said message embedded in a modulated signal to the satellite; downlink transmission by the satellite of a signal incorporating said modulated signal incorporating the message to a terrestrial station connected to the server device;

the modulated signal incorporating the message sent by the client device is modulated according to a spread spectrum protocol operating according to a spread spectrum multiple random access asynchronous protocol;

said transmission of the content by the server device to the client device is performed by a satellite transmission; said client device creates said message including said URL address in a compressed format;

said server device ignores the message when it has already sent the requested content asynchronously and the client device has sent said message before receiving the content;

said client device receives and saves in its "cache" memory all the content sent by the server asynchronously. Thus, if the forward channel is a broadcast or broadcast type of channel (thus received by many client devices at the same time), such a step makes it possible to fill the "cache" memories of the client devices, by increasing the probability that the content is already there when the user asks for it;

said server device marks certain files incorporating content with one or more indicators such as flags so that they are received and stored by several client devices at the same time. This targeting by means of indicators makes it possible to increase the probability of satisfying a request from the user by using the cache memory of the client device.

The present invention also relates to a client device and a server device for implementing the method according to the invention.

Other features and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended figures:

FIG. 1 schematically represents a transmission / reception installation for implementing the method according to the invention;

FIG. 2 illustrates the different steps of the method according to the invention.

FIG. 1 schematically represents a transmission / reception installation 1 for implementing the method according to the invention. It is understood that the installation 1 is given for illustrative purposes and that many variants are possible for the implementation of the method without departing from the scope of the present invention.

The transmission / reception facility 1 comprises: a parabolic reflector 3 adapted to receive signals received from a first satellite 102 and to transmit signals to a second satellite 103;

a transmitting / receiving unit 2 (for example outside a house);

a coaxial cable 20;

a housing 21 (for example intended to be housed inside the house).

The parabolic reflector 3 for example receives signals from the Ku-band satellite 102 (10.7 GHz - 12.75 GHz) and transmits signals to the satellite 103 in the C-band (5.85-6.42 GHz) or in the Ka-band (29.5 -30 GHz); it will be noted that the information concerning the frequencies used are given for purely illustrative and non-limiting purposes. In addition, even if the invention is here described with two satellites, it is understood that the use of a single satellite for the forward channel and the return channel is also possible.

The transmitting / receiving unit 2 comprises:

an LNB block 4;

an emission block 9;

- a radio frequency coupler / decoupler of radio signals

15.

It may then be advantageous to use an add-on device 33 of the transmit / receive block 9 on the LNB 4 of the parabolic receiver already equipped, pointed and adjusted without it being necessary to modify the mounting or the adjustment existing antenna. Such an add-on device 33 is for example described in the patent application FR08 / 56940.

The housing 21 comprises:

a coupler / decoupler 22;

a modulator 25;

a demodulator 24;

a client device 101 whose characteristics will be specified in the remainder of the description; means 26 for wireless connection to a WiFi type local network capable of providing an interface between the client device 101 and a user terminal 100;

an output 32 adapted to deliver demodulated signals by the demodulator 24 to a satellite decoder 31, also known as STB ("Set Top Box" in English).

The coaxial cable 20 connects the housing 21 via its coupler / decoupler 22 and the transmission / reception unit 2 via its coupler / decoupler 15.

The demodulator 24 is for example a demodulator operating according to the DVB-S2 standard.

The modulator 25 operates, for example, according to an SPREAD ALOHA modulated band spreading multiple random access asynchronous protocol optimized for the satellite hub to be able to use means for eliminating interference (such a protocol is for example described in FIG. standard described in ETSI TS 102 721 -3: "Satellite Earth Stations and Systems, Air Interface for S-Band Mobile Interactive Multimedia (S-MIM), Part 3: Physical Layer Specification, Return Link Asynchronous Access.") .

The set of signals is coupled on the single coaxial cable 20.

The installation 1 is based on a part operating in the forward channel for receiving TV signals and Ku-band data transmitted by a terrestrial station (satellite hub) 104 (equipped with a DVB-S2 modulator / encapsulator) and a demodulator operating according to an asynchronous bandwidth multiple random access protocol) to the satellite 102, and a C or Ka band return channel from the satellite 103 to said station 104 enabling the setting up of interactive services (voting, consumption of conditional access content through the exchange of keys, orders for new services such as video on demand).

There is a strong imbalance in terms of the bit rate between the forward and the backward path so that the use of the TCP / IP protocol reliably and efficiently is impossible.

The method according to the invention will advantageously use this return path to allow a user equipped with a user terminal 100 (for example example a smartphone, a PC or a touch pad) equipped with a web browser connected to the client device 101 to access the content of HTML pages via its browser. To do this, the hub 104 is equipped with a server device 105 connected to the Internet network 106 and whose characteristics will be specified in the following description.

The various steps of the method 200 according to the invention are illustrated with reference to FIG.

The client device 101 comprises:

a set 1 1 1 comprising a DHCP server 109 (Dynamic Host Configuration Protocol) and a DNS server 1 10 (Domain Name System);

a cache memory 108;

client means 107 for receiving push-mode data streams connected to the demodulator 24.

The server device 105 comprises:

a cache memory 1 12;

means 1 13 of connection to the Internet;

means 1 14 for transmitting data streams in push mode;

means 1 for receiving the messages sent by the terminals.

We start from the assumption that the client device 101 is configured as an HTTP proxy server for the browser of the terminal 100. This configuration can be manual or through a response to a DHCP request if the user terminal supports this technology ( WPAD "Web Proxy Auto Discovery").

According to a step 201, the user terminal 100 transmits an HTTP request including the URL address (which it seeks to obtain the content, typically a web page) to the client device 101.

According to a step 202, the reception of the URL address by the client device 101 causes the client device 101 to check the presence of the content of said URL address in its cache memory. If the content is present, the HTML page corresponding to the URL is directly transmitted to the user terminal via the established TCP connection. This case can occur, for example, if the page has already been requested by the user.

According to a step 203, in the absence of the content of the URL address in its cache memory, the client device 101 creates a short message including the URL address. To send this message, the client device 101 uses, for example, the modulator 25 operating according to an SPREAD ALOHA modulated band spreading multiple random access asynchronous protocol. It should be noted that the client device 101 may also carry out a preliminary step of compressing the data to be sent for example by using a ZIP algorithm so as to obtain only one short message integrating the URL address, even if if the URL is very long. As we will see more in what follows, the message will then be sent via the return channel of the installation 1 (here in C or Ka band). The invention is however not limited to a satellite return channel and it is also possible to create a short message of the SMS type which will then be transmitted by terrestrial return (GPRS connection or GSM-SMS). It will be noted here that the outward and return paths can be completely decoupled; at the extreme, the message can be transmitted as a sequence of dialed digits on a telephone line with a keyboard (ie the tones are used in the back-end telephone). Similarly, it is perfectly possible to envisage other possible scenarios, for example that the client device that sends the request is not the same as the one that receives the requested content.

According to a step 204, the message is then transmitted by the client device 101 to the server device 105 according to a connectionless unidirectional transmission protocol. As indicated above, the message is for example sent on the return channel of the installation 1 so that the message passes through the satellite 103 and is then retrieved by the hub 104. The server device 105 is either integrated with the hub 104 or communi- with him. The server device 105 will use the demodulator operating according to an asynchronous bandwidth multiple random access protocol to retrieve the URL address. According to a step 205, the server device 105 verifies the presence of the content of the URL address in its cache memory.

According to a step 206, in the absence of the content of the URL address in its cache memory, the server device 105 connects to the Internet 106 to download the web page corresponding to the URL.

According to a step 207, the server device 105 can also pre-load ("pre-fetching" in English) by retrieving information that the user is likely to want to visit in the near future. To do this, the server device 105 analyzes the downloaded HTML web page to find the images and other elements whose link is contained in said HTML page. The HTML page and the associated elements / images are downloaded and stored in the cache memory of the server device 105.

According to a step 208, the server device 105 then creates a single file (for example a compressed file in .zip format) including the HTML page as well as the pre-loaded elements / images.

According to a step 209, the server device will use its push data transmission means to transmit the file via a protocol used for the "push" technology (also called "datacast"), ie a protocol unidirectional with coding without acknowledgment. This "datacast" protocol may require additional operations such as the addition of error correction codes so as to guarantee a very high probability of transmission without errors. The file as such is transmitted via a physical level protocol such as DVB-S2 by transiting for example by the satellite 102.

The principle of push content delivery is that there is no connection to initiate, and the content can be received by several or all client devices at the same time.

According to a step 210, the client means for receiving a push data stream of the client device 101 includes software means that constantly listen and receive what is broadcast by the server device. Thus, the client device 101 retrieves the HTML page corresponding to the URL address as well as the elements of said page whose link is contained naked in the page. Once recovered, the page and the elements are stored in the cache memory of the client device 101.

According to a step 21 1, the user terminal 100 which communicates with the client device via its TCP connection receives the HTML page. Thanks to the prefetching performed, the user terminal 100 can also have quick access to the information targeted by the links contained in said page and stored in the cache memory of the client device 101.

If the client device 101 is not configured as a proxy browser, a possible mechanism is illustrated in FIG.

According to a first step 301, the client device 101 which comprises a DHCP server receives a DHCP request from the terminal 100 and allocates a local IP address for the terminal 100; it saves this address associated with the terminal in its cache memory. The client device 101 transmits its own IP address as the default DNS server and gateway at the terminal 100.

In a step 302, the terminal 100 transmits a DNS request to the client device 101 corresponding to the URL address entered in the browser.

In a step 303, the client device 101 verifies the presence of the name of the server server associated with the DNS request in its cache memory.

According to a step 304, if the server name associated with the DNS request is present in the cache memory, the client device 100 transmits to the user terminal 100 the IP address already associated with the server name.

According to a step 305, if the server name is not present in the cache memory, the client device 100 creates a temporary IP address associated with the server name and then transmits it to the user terminal 101; this temporary IP address is also stored in the cache memory. The temporary IP address is a dummy address that does not actually correspond to the IP address of the server name, the only condition being that this temporary address does not belong to the local network of the user terminal 100. In others In other words, the client device 101 dupes the terminal 100 by sending him a "fake" address as if he had resolved the server name.

In a step 306, the user terminal 100 attempts to establish a TCP connection with the server corresponding to the temporary IP address; in fact, the client device 101 substitutes itself for the server by assigning itself said temporary IP address so that the TCP connection is established between the user terminal 100 and the client device 101; the client device 101 simulates a TCP connection between the user terminal 100 and the server associated with the URL. At this level, step 201 is described with reference to FIG. 2.

It is understood that in the description of the process steps as illustrated in FIGS. 2 and 3, the steps are not necessarily sequential; the different devices (in particular the client device 101 and the server device 105) each follow their own steps, said devices being able to operate in parallel.

The client device and the server device are intended for managing the different operations to be performed in order to implement the method according to the invention. To do this, they comprise several software means (i.e. applications) some of which are dedicated to the implementation of the invention. In other exemplary embodiments, these software means could be replaced by specific electronic circuits.

Of course, the invention is not limited to the embodiment just described.

Thus, the invention has been more particularly described in the case of use in C or Ka band but it can also be used in satellite S band (1980 - 2010 MHz and 2170-2200 MHz).

Furthermore, even if the forward channel has been more specifically described in the case of DVB-S2 modulation / demodulation, it is understood that other modulations / demodulations may be used such as DVB-T, DVB-T2 standards. , DVB-S or DVB-SH.

Similarly, the pre-fetching steps can go beyond the links contained in the requested page so that the server device can also download particularly requested pages ("best of the web), which will then be stored in the cache memory of the server device and client devices. In this case, we will speak of an "advanced caching" operation. To do this, the server can use indicators that are recognized by all clients targeted by this content: these clients will receive and store the content even if the user did not request it.

Claims

1. A method of retrieving content in the form of an HTML page corresponding to a URL by a client device comprising the steps of:

receiving said single file by the client device;

recovering and storing by the client device of said single file in said memory.

2. Method according to the preceding claim characterized in that it comprises a step of extraction by the client device from said single file of the content as well as previously downloaded elements whose link is contained in said content, storing said content and said previously downloaded elements in the memory of the client device, and providing a user terminal with said content and said previously downloaded elements.

3. Method according to one of the preceding claims characterized in that it comprises a step of verification by the server device of the presence of the content URL address in a memory of the server device so that said download on the Internet by the server device of the content corresponding to said URL is in the absence of the content of the URL in the memory.

4. Method according to the preceding claim characterized in that said server device sends said elements asynchronously, said client device being ready to receive said elements and to store them in its memory.

5. Method according to one of the preceding claims characterized in that it comprises the following steps:

an attempt to open the link associated with the URL address on the browser of a user terminal;

- transmitting a DNS request from said user terminal to the client device;

- verification by the client device of the presence of the server name associated with the DNS query in a local database of the client device;

if the server name is present in said database, transmission by the client device to the user terminal of the IP address already associated with said server name;

if the server name is not present in said database, creation by the client device of a temporary IP address associated with said server name then transmission by the client device to said user terminal of said temporary IP address and recording said temporary IP address in said database; attempting to establish a TCP connection by the user terminal with the server corresponding to said temporary IP address, said client device replacing the server by assigning itself said temporary IP address so that the TCP connection is established between the terminal user and the client device;

transmission of an HTTP request including the URL address by the user terminal to the client device, receipt of the URL address by the client device resulting in said step of verification by said client device of the presence of the content of said URL address in a memory of the client device;

- recovery of the content by the client device and sending the content to the user terminal through the established TCP connection.

6. Method according to one of the preceding claims characterized in that said unidirectional protocol with coding without acknowledgment is one of the protocols used for the technology "push" also called "datacast".

7. Method according to one of the preceding claims characterized in that said transmission of the message by the client device to the server device is performed by a satellite transmission, said method comprising the following steps:

uplink transmission by the client device of said message incorporated in a signal modulated towards the satellite;

downlink transmission by the satellite of a signal incorporating said modulated signal incorporating the message to a terrestrial station connected to the server device.

8. Method according to the preceding claim characterized in that the modulated signal incorporating the message sent by the client device is modulated according to a spread spectrum protocol operating according to a spread spectrum multiple random access asynchronous protocol.

9. Method according to one of the preceding claims characterized in that said transmission of the content by the server device to the client device is performed by a satellite transmission.

10. Method according to one of the preceding claims characterized in that said client device creates said message including said URL address in a compressed format.

1 1. Method according to one of the preceding claims, characterized in that said server device ignores the message when it has already sent the requested content asynchronously and the client device has sent said message before receiving the content.

12. Method according to one of the preceding claims characterized in that said server device marks some files incorporating content with one or more indicators such as flags for them to be received and stored by several client devices at the same time.

13. Method according to the preceding claim characterized in that said client device receives and stores in its memory all the files that are marked by the server device with an indicator present in a pre-established list.

14. Customer device comprising means for implementing the method according to any one of the preceding claims.

15. Server device comprising means for implementing the method according to any one of claims 1 to 14.