Process and apparatus for downloading digital data on a terminal after measuring the data reception rate for the terminal

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DESCRIPTION

Procedure and device for downloading digital data in a terminal after measuring the flow in reception for the terminal.

The present invention relates generally to the measurement of the flow available at reception for a client terminal connected to a communication network and capable of downloading digital data from a data server.

The interest of such a measurement is in particular to select a coding stream more appropriate to the stream available at reception for the client terminal before sending it the data.

There are measurement software to install on the client terminal. Software of this type periodically measures the amount of data that transits at a given protocol level on access to the network to one or more computers connected to the network. This software is independent of the computers that generate the data traffic. It is not adapted to measure the flow in reception for a terminal. Indeed, it provides statistical results on the network, intended for an operator and not for a data server.

On the other hand, there are measurement software installed on the server side. A software of this type measures the amount of data that transits at a given protocol level on the access to the network towards a client terminal.

For example, US 2002044528, US 2002165970 and EP 0622967 have dealt with measurements performed on the server side.

Patent application US 2002/0161913 discloses a method for downloading data to a client terminal from a remote server, in which the client terminal measures a data transfer flow with the remote server prior to downloading, using the packets exchanged during a connection to the distant server. The corresponding data transfer flow measurement application is eventually downloaded from the Internet.

This type of architecture has the following drawbacks. Flow measurement is performed by a given server, for the specific needs of this server. It will then be necessary to repeat the measurement for each server. Furthermore, the server must implement a traffic generator coupled to a traffic absorbing application at the client terminal.

On the other hand, it is desired that the flow measurement be carried out very quickly.

The present invention aims to solve the drawbacks of the prior art by providing a method and a device for downloading digital data for a client terminal adapted to be connected to a data server by means of the communication network, which allow a measurement of the flow available at reception for the client terminal that is not connected to a specific server while being fast to carry out.

To this end, the invention proposes a method for downloading digital data according to claim 1.

Thanks to the invention, the measurement of the flow available at reception for a client terminal is carried out independently of the reception of digital data from the data server. The measurement is not tied to a specific server.

According to a preferred characteristic, the file comprises data packets, and the step of measuring a download flow of the test file comprises

- the measurement of a download flow after the receipt of each packet,

- the verification of a stability test of the measured flows,

- the interruption of the downloading of the test file and the measurements when the stability test is verified.

Thus, the flow measurement is carried out quickly.

According to a preferred characteristic, the measurement of a download flow after the reception of each packet is performed between a packet of predetermined order in the test file and the last packet received.

The measurement results quickly tend towards a stable value.

More precisely, the measurement of a download flow after the reception of each packet is performed between the end of the reception of the first packet in the test file and the end of the reception of the last received packet.

Alternatively, the measurement of a download flow after the reception of each packet is performed on a predetermined number of last received packets.

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According to a preferred characteristic, the stability criterion is verified when the difference between the flow measurements in the reception of two consecutive packets, in a predetermined interval of packets, is less than a predetermined threshold.

This criterion is simple to implement and monitor.

The invention also relates to a client terminal according to claim 7 which comprises means for putting into practice the method set out above.

The client terminal presents advantages analogous to those previously explained.

The invention also relates to a computer program according to claim 8 which comprises instructions for putting into practice the procedures presented above.

Other characteristics and advantages will appear upon reading the preferred embodiments described with reference to the figures in which:

- figure 1 represents an embodiment of a device according to the invention,

figure 2 represents a first embodiment of a device according to the invention,

figure 3 represents an embodiment of the flow measurement method according to the invention,

figure 4 represents a second embodiment of a device according to the invention,

- figure 5 illustrates the flow measurement.

According to an embodiment of the invention represented in figure 1, the device comprises a client terminal 1 connected to a communication network 2. A data server 3 is also connected to the communication network 2. The data server 3 is For example adapted to provide a set of data according to a range of different predetermined streams, according to a streaming technique, called "streaming".

The data set is provided in the client terminal 1 to a flow that must in particular be adapted to the maximum flow that the terminal 1 can receive.

According to the invention, a server 4 hosting the flow measurement application and a test server 5 are connected to the communication network 2.

The flow measurement device available at reception for the client terminal 1 connected to the data server by means of a communication network, comprises:

- means for connecting the client terminal 1 to the server 4 hosting the flow measurement application,

- downloading means on the client terminal of a flow measurement application, from the host server of the flow measurement application,

- means for activating the flow measurement application, this application comprising the steps of:

- connection from client terminal 1 to test server 5,

- downloading a test file to the client terminal from the test server,

- measurement of a download flow of the test file.

The operation of servers 4 and 5 is explained below. It should be noted that servers 4 and 5 can be physically grouped into a single server. Also, servers 4 and 5 can be clustered with data server 3.

Figure 2 represents the interactions of the elements of Figure 1, according to a first embodiment of the invention.

Figure 3 represents a corresponding flow measurement method in the form of an algorithm comprising steps E1 to E15.

Stage E1 is the display of an HTML page on the client terminal. This page proposes to carry out a cash flow measurement in reception for the client terminal 1. It is assumed that the user demands the flow measurement.

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The next step E2 is the sending of a request to download a flow measurement application from the client terminal 1 to the server 4 hosting this request. This application is available in the form of an HTML page.

Step E3 is the installation of the HTML page containing the flow measurement application on the dedicated server 4. This step also comprises waiting for the reception of a request to download the flow measurement request.

The next stage E4 is the reception, by the server 4, of the download request of the flow measurement application that comes from terminal 1.

The next step E5 is the sending of the HTML page containing the flow measurement application, from the server 4 to the client terminal 1.

Step E6 is the reception of this page by the client terminal 1.

The next step E7 is the sending of a request for a test file, from the client terminal to the test server 5.

Step E8 is the receipt of the test file request by the test server 5, which was in a waiting state.

The next step E9 is the sending of the test file from the server 5 to the client terminal 1. The test file comprises data that is transmitted in the form of data packets. For example, the transmission is carried out in the form of 50 packets of 4000 bytes each.

Step E10 is the progressive reception of the test file by the client terminal and the simultaneous measurement of the available flow is reception.

The measurement is carried out as follows, illustrated in figure 5. The end times of the packet reception are considered. The end of reception of the first packet P₀ is an initialization of the received octet count and an initialization t₀ of the reception instants. This means that the content of the first package is not taken into account.

Then at the end of the receipt of each packet P_n, the number of octets received since the initial time t is accumulated₀. The flux is the ratio of this cluster to the difference in current time t_n with the initial time t0.

In a variant, the flow calculation is carried out on a predetermined number of last received packets.

The reception of the test file packets and the flow measurement are carried out as long as the measurement result does not stabilize. The stability criterion is verified when the absolute value of the difference between the flow measurements upon receipt of two consecutive packets, in a predetermined interval of packets, is less than a predetermined threshold. The threshold is for example equal to 2%.

When the stability criterion is verified, the flow measurement is finished. The last value measured is the flow available at reception for client terminal 1.

Step E10 is then followed by step E11, which constitutes the end of the measurements and the interruption of the download of the test file.

In the next step E12, the client terminal 1 requests from the data server 3 a PHP page with parameters of the measured flow.

According to a particular embodiment, the PHP page request is made to an intermediary server.

In a variant, it is not the measured flow that is integrated into the request, but a stable flow value compatible with the measured flow. In this case, the possible flow values ​​have been previously downloaded, for example with the flow measurement application.

The data server 3 comprises a set of data, for example audiovisual content, available according to different streams, in the form of several files each corresponding to a stream.

In step E13, the server 3, or the intermediary server, receives the PHP page request, accompanied by the stream available in reception for the client terminal, or the stable value of stream. Server 3, or the intermediary server, creates an HTML page that indicates a preferential flow of data delivery. The preferential flow depends on the measured flow.

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The next step E14 is the sending of the HTML page created to the preceding step from the data server 3 or the intermediary server to the client terminal 1.

For example, if the measured stream is between 0 and 48 kbit / s, the server sends an HTML page indicating that the requested data cannot be sent with that stream.

If the measured stream is between 48 and 120 kbit / s, the server sends an HTML page indicating that the stream best suited for sending requested data is a 40 kbit / s stream.

If the measured flow is between 120 and 360 kbit / s, the server sends an HTML page indicating that the most suitable flow for sending requested data is a 100 kbit / s flow.

If the measured flow is between 360 and 840 kbit / s, the server sends an HTML page indicating that the most suitable flow for sending requested data is a 300 kbit / s flow.

If the measured flow is higher than 840 kbit / s, the server sends an HTML page indicating that the most suitable flow for sending requested data is a 700 kbit / s flow.

In step E15, the client terminal 1 receives and displays the HTML page sent by the data server 3 or the proxy server.

The client terminal can then request the data server 3 to download the data set. For this, the user has at his disposal the most adapted flow.

A second embodiment is represented in FIG. 4. In this embodiment, the flow measurement request is made simultaneously with a request to download a data set. The flow measurement request can even be made in a transparent way for the user.

The operation of this embodiment is analogous to the preceding one, with the exception of the following differences.

When the application of the flow measurement is downloaded on the client terminal, it is accompanied by a set of addresses. Each of the directions corresponds to the data set to a particular flow.

When the available flow has been measured, the client terminal requests the data set directly from the available flow, by means of its address.

Of course, variants of realization are possible. In particular, when the available flow has been measured, it is possible to propose to the user of the client terminal various download flow values, determined as a function of the measured flow and compatible with it. The user then selects a flow value, which then overrides the measured flow value. In particular, it is the selected value that is taken into account for the download of the data set.