EP1510040A1

EP1510040A1 - Wireless local access network test device

Info

Publication number: EP1510040A1
Application number: EP03756010A
Authority: EP
Inventors: Florent Prat; Vincent Fargue
Original assignee: 6LAN
Current assignee: 6LAN
Priority date: 2002-05-30
Filing date: 2003-05-27
Publication date: 2005-03-02
Also published as: FR2840481B1; AU2003251107A1; WO2003103219A1; FR2840481A1

Abstract

The invention relates to a test device (15) which permits the analysis of the connection quality at an access point to a wireless local access network, from a location which houses computer equipment, including a wireless communication card, characterised in being in the form of the body with a housing (9), for the interchangeable housing of a wireless communication card (16), means for processing emitted and/or received signals going to or coming from an access point to the network and means for displaying (17) information relating to said signals.

Description

WIRELESS LOCAL AREA TEST APPARATUS

Technical area

The invention relates to the field of wireless computer networks. It relates more specifically to a test device which can be used to optimize and or validate the configuration of a wireless local area network, in particular with regard to the equipment used, and the locations of the various access points to the network. The invention makes it possible in particular to test the radio links meeting the standards IEEE 802.11, HomeRF and HiperLAN.

Previous techniques

In the area of computer networks, there is a significant development of wireless local area networks, also called WLAN, for "Wireless Local Area Network". This type of network has great advantages over wired networks, due to the flexibility of their interface, which allows a user to move within the area covered by the network, while remaining connected.

In general, the various computer equipment, such as workstations, printers or other peripherals, are connected to the rest of the network by a radio link.

This radio link therefore makes it possible to connect each item of equipment with a network access terminal, equipment called "access point", or "bridge".

The various access points to the network are linked together, either by a radio link, or by wired links.

The quality of the radio link between IT equipment and the corresponding access point is decisive for the proper functioning of the network, and in particular for access to the network equipment with sufficient speed. However, the quality of this radio link depends in particular on the type of equipment used, and especially on the location of access points, and the locations intended to accommodate computer equipment. This is why, during the installation of a wireless local area network, it is necessary to carry out a certain number of checks in order to ensure the quality of the connection to the various access points from the premises. likely to host IT equipment.

To date, different methods or materials are used to perform these checks.

Thus, in a first approach, it may be possible to estimate the quality of the connections from a theoretical modeling of the configuration of the premises, the location of the different access points, and the type of equipment used. Software is used to assess the theoretical gains and speeds corresponding to such a configuration.

It is obviously understood that deviations can be observed between the theoretical calculations and the real gains and debits, so that this method based solely on a theoretical evaluation is not really satisfactory.

In a second approach, the quality of the connections can be checked using a laptop computer, which is equipped with test software. This test software, for example that marketed by the company AVAYA under the reference "Orinoco Client Manager" makes it possible to determine the value of the gain between a signal emitted by an access point and the portable computer, which is equipped with a wireless communication card.

Such a solution is not really satisfactory, since it does not really allow the proper functioning of the network to be analyzed, but simply the measurement of a gain. The network throughput is in fact simply estimated from the measured gain values, so that when the network is actually loaded, the actual throughput values very often differ from these theoretical throughput values. In addition, this verification mode requires the use of a portable computer, which can be cumbersome. In addition and above all, the measurements made by this type of method are eminently dependent on the type of equipment used, and in particular on the communication card associated with the laptop.

A third method is known for testing the quality of the connection, which uses specific test devices, such as in particular those sold by the company Berkeley Naritronic System, under the reference LOCUST.

Such a device is in the form of a box which, comprises a transmitter of radio waves, capable of transmitting in the frequency range corresponding to the local network. This device makes it possible to display a certain amount of information relating to the quality of the connection, and in particular the gain and the signal to noise ratio. This type of device has several drawbacks, and in particular the fact that it does not allow the network to be loaded and to verify what the actual bit rate that the network can withstand. In addition, the radio transmitter uses proprietary communication software, and the results obtained are therefore not representative of those obtained with the products installed definitively since they too use other proprietary software. This type of transmitter therefore does not have the same characteristics as on the communication cards associated with the various computer equipment, intended to be connected to the network.

In other words, the analysis of the quality of the connection made by this type of device can deviate from the actual performance results, observed with the equipment which will be connected to the network.

A first problem which the invention proposes to solve is that of allowing as complete an analysis as possible of the quality of the radio link with the access point to the network, in particular by determining throughput values corresponding to load situations. of the network. Another problem which the invention proposes to solve is that of allowing an analysis of the connection quality which takes into account the type of hardware which will be used on the computer equipment intended to be connected to the network, with the great diversity that the 'we know.

Statement of the invention

The invention therefore relates to a test device, making it possible to analyze the quality of the connection to an access point of a wireless local area network, from a place capable of accommodating computer equipment including a card. wireless communication.

The test apparatus according to the invention is characterized in that it is in the form of a housing, comprising: a housing adapted to receive interchangeably a wireless communication card; means for processing the signals transmitted and / or received to and / or from the network access point; means for displaying information relating to said signals;

In other words, the device according to the invention can receive different communication cards, which are advantageously chosen to have properties similar to those which are mounted on the equipment intended to be installed at the site of the test.

Thus, advantageously in practice, the housing of the device can be configured to receive wireless communication cards of the PCMCIA type (for "Personal Computer Memory Card International Association").

In the case where the computer equipment intended to be connected to the network are portable computers, equipped with a housing for receiving a PCMCIA card, the communication card mounted in the test apparatus may be an identical card, or whose the transmitting part has identical or equivalent properties and characteristics. Thus the user can integrate into the device a PCMCIA card of manufacturer and reference identical to those used definitively on the site tested.

Of course, other computer hardware than laptops can receive communication cards in PCMCIA format.

In the case where the IT equipment intended to be installed on the network has communication cards of a different format, a PCMCIA card to be inserted in the test device will be chosen, a card of which the transmitting / receiving part proper has the same characteristics and properties.

By this arrangement, the results of the analysis of the quality of the connection will be very representative of the real situation, when the computer equipment is connected to the network.

Advantageously in practice, the processing means associated with the test device are capable of controlling the operation of the associated communication card according to a program or pilot, selected from a predetermined list.

In other words, the test device contains the various configuration files or drivers, which allow the communication card to operate.

These files are advantageously identical to those which will be mounted in the computer equipment, so as to obtain an analysis result corresponding as closely as possible to the reality of the network.

Advantageously in practice, the test apparatus also comprises means for updating the predetermined list of pilots, so as to be able to use the latest versions of pilots, or more generally, versions corresponding to those installed on the equipment. computer, intended to be connected to the network. According to another characteristic of the invention, the test device also includes means for recording information relating to the signals transmitted and / or received to and / or from the network access point, so as to be able to to establish a certain number of statistics, concerning this connection.

Advantageously in practice, the test device may also include means of transfer to a computer, various data relating to the signals exchanged with the network access point.

In this way, it is possible to perform more sophisticated processing and / or backups of the test data on a separate computer.

According to another characteristic of the invention, the test device is programmed so that the processing means are capable of transmitting data packets or frames according to a protocol compatible with the wireless local area network.

In this way, the sending of these frames makes it possible to verify the operation of the network when the latter is in charge, which makes it possible to analyze the evolution of the bit rate as a function of this charge.

Advantageously in practice, the processing means are capable of transmitting frames of different length, in order to determine the evolution of the bit rate as a function of the type of frame transmitted.

Advantageously in practice, the length of the frames can be configurable by the user, so as to allow him to perform different types of tests, corresponding to different situations of network use.

Likewise, the frame sending tasks can be scheduled to be performed repeatedly, and for predetermined durations, corresponding to other types of network use. Brief description of the figures

The manner of carrying out the invention, as well as the advantages which result therefrom, will emerge clearly from the description of the embodiment which follows, given by way of nonlimiting example, and in support of the appended figures, in which:

Figure 1 is a schematic view illustrating part of a wireless local area network. Figure 2 is a summary perspective view of the test apparatus according to the invention.

Way of realizing the invention

As already mentioned above, the invention relates to a test device intended to analyze the quality of radio links for connection to a wireless local area network.

In the configuration illustrated in Figure 1, the local network (1) is represented by a number of bridges (2) connected together by wire connections (3), and also connected for example, to a server (4). Of course, this is a schematic representation, and the invention makes it possible to analyze the properties of the type of wireless networks of very varied architectures, which can be particularly complex.

More precisely, each bridge (2) constitutes an access point to the network, and is equipped with transmission and reception means including in particular an antenna (6).

These bridges (2) are arranged in appropriate places in the premises in which the network is deployed. This or these bridges can be the existing equipment on the market, and intended to be physically implanted in the network being deployed. In some cases, network access points can be simulated by specific equipment, commonly called "beacons", used only during the installation phase. These "beacons" are equipment playing the role of bridges, but with limited performance. They therefore have the same components ensuring the communication functions as the bridges they simulate. The objective of the invention is to make it possible to determine the quality of radio link between a bridge (2) forming a network access point, and computer equipment (10) located at a determined location.

In the illustrated form, this equipment is represented in the form of a computer (10), on which is mounted a wireless communication card (11).

This card (11) can be of the plug-in and extractable type, according to the PCMCIA standard. It may more commonly be an expansion card of the PCI type (known as a cradle card), permanently mounted in the central unit of the computer (10) and supporting a PCMCIA card.

It could also be a wireless communication module, connected by another means to the central unit, for example by a USB type link.

Of course, other computer equipment can be connected to the wireless network, such as printers, barcode readers, personal organizers (PDA types), mobile phones ...

IT equipment can also be simulated by "beacons" as mentioned above, especially during the network deployment phases, before the final hardware is installed. In this case, each tag has a wireless communication card allowing it to be connected to the network via the bridge (2), or a bridge with limited performance, formed by a tag. In this way, a network comprising several linked computer equipment can be realistically simulated, even before the final installation.

The invention therefore relates to a test device (15), as illustrated in FIG. 2, which makes it possible to analyze the quality of the radio link with respect to the wireless network.

This portable device (15) can be moved within the range of the bridge (2). It may in particular be arranged at the future locations of the various pieces of equipment which will be intended to be connected to the network (1). In accordance with the invention, this test device (15) is in the form of a box, which includes a microcontroller, intended to provide a data processing function, a radio link card, as well as an interface ( 17,18) to display the calculated data and enter the instructions. This microcontroller allows quick start-up and quick stop of the box. The box can operate either connected directly to the mains via an integrated power input (22) or with rechargeable batteries, possibly via the input (22), or not.

More precisely, the microcontroller can be mounted on a card, for example on the PC 104 or ETX / ENCORE foπnat or on a card developed specifically for the application. This card is associated with an additional card, compatible with the microcontroller card, and arranged to receive a PCMCIA type wireless communication card (16).

In a particular form, this additional card (16) can receive several cards of the PCMCIA type, one of which is used for the radio link, the other can be used for ancillary functions, such as in particular data backup.

An important characteristic of the invention resides in the possibility of interchanging the wireless communication card (16) in order to use a card identical or analogous to that which equips the computer hardware intended to be connected to the network.

As already mentioned, these may be identical cards, if these devices are equipped with PCMCIA type cards. Similarly, when the cards mounted in computers, for example, are PCI type cards, the PCMCIA card (16) chosen to be inserted in the test box will be the same as the PCMCIA card inserted in the PCI cradle card. In the context, for example, of a USB box integrating a transmit / receive module, the PCMCIA card (16) chosen to be inserted in the test box will be a card whose transmit / receive module (20) is analogous, i.e. has properties and characteristics identical or extremely close to that (11) mounted in the computer (if possible from the same manufacturer).

The similarity between the two communication cards also involves the use of configuration files, or drivers, which are also identical or analogous.

Indeed, the test box (15) ensures the operation of the communication card, as well as the exchange of information, according to a pilot which is dedicated to the card, and which can advantageously be the same as that which will be mounted in IT equipment in connection with the network.

This possibility makes it possible to test the quality of the radio link under software and hardware conditions particularly close to those which will prevail when the final computer equipment (10) is linked to the network.

To do this, the housing (15) comprises memory means, including a set of drivers corresponding to each of the communication cards which can be inserted into the housing. This driver can be loaded automatically depending on the type of card inserted in the box, or even be chosen precisely and on demand by the user by access via a menu.

These drivers can also be downloaded within the box, either via a wired link, connected for example by a serial link to the box, or by any other type of link, in particular parallel or USB.

Of course, the downloading can also be carried out by the intermediary of the hertzian link, via the communication card (16) or via an integrated memory card reader (23) of the COMPACTFLASH type. The box can integrate communication functionalities according to a TFTP protocol allowing in particular the dialogue with the beacons simulating the computer equipment of the network, or the bridge with limited performances. In operation, the processing means including the box make it possible to calculate and display different quantities relating to the operation of the network. Among these quantities, we can notably cite the signal level received both from the bridge (2) and from the card (11), as well as the noise level, and therefore, the signal to noise ratio. The quality of the link can also be characterized by the link speed and the gain. These parameters will therefore be analyzed and can be saved, bi-directionally, either at the level of the bridge (2) or of the card (11).

Other parameters relating to the link can be processed by the box (15), and in particular the parameters for identifying the network and the bridge used, as well as the communication channel in operation.

The fact that the link is encrypted or not can also be determined by the processing means.

According to another characteristic of the invention, the box (15) is configured to send data sets, also called frames, to the bridge, to verify the proper functioning of the network under load.

These frames can, for example, be configured according to the Internet Protocol (LP), and conventionally include information relating to the address of the transmitter, the address of the receiver, the type of data transmitted, as well as CRC type verification codes.

The processing means are capable of transmitting frames of different lengths, corresponding to different load states of the network, these lengths being able to range from a few hundred to a few thousand bytes.

Different operating modes can be implemented, corresponding to different tests. Frame trains of identical or variable lengths can be sent, either on an ad hoc basis or continuously, so as to verify their correct transmission to the bridge, by analyzing the acknowledgment frame sent by the bridge. Adjustments to the duration of the test as well as the length of the frames can be made by the user.

To do this, the user has a keyboard (18) at his disposal on the housing. This keyboard can include different keys as in the form illustrated in FIG. 2, or even include a number of lower keys, making it possible to navigate in menus displayed on the screen (17) of LCD type for example. The keyboard can also include levers (or "joy sticks"), or even devices of the integrated touch mouse type, or touch screen zones.

The processing means are configured to authorize the modification of the transmission power, as well as the frequency in the range accessible by the communication card.

The processing means are also configured to authorize rates corresponding to the IEEE 802.11 standard. These bit rates can adopt values of 1, 2, 5.5 and 11 megabits / second, but the processing means are configured to adapt to different bit rates if necessary, for example the values of 54, 36, 24, 12 and 6 megabits / second for standard 802. a

The processing means are configured to display a certain number of information at the level of the screen (17) installed on the housing.

The list of information displayed corresponds to that mentioned above. This list can possibly be configured according to the user's wishes and according to the evolution of standards and drivers associated with the cards. The data relating to the different links, as well as to the different load test operations, can be saved within the box, or else transmitted either by a wired link or by a radio link intended for a remote computer, which allows statistics, but also backups or other iterative analyzes.

These backups may, for example, be carried out using a reader / writer of memory cards of the COMPACTFLASH type integrated into the housing (23).

Of course, the connection of the box (15) with any computer equipment makes it possible to download at the same time the most recent version of the software intended to operate the processing means, as well as the various updates of drivers or drivers. communication cards that can be installed in the test device.

It appears from the foregoing that the test apparatus according to the invention has multiple advantages, and in particular: a possibility of receiving communication cards corresponding in their hardware and software part, to those which will be used in the materials subsequently connected wireless network; the possibility of carrying out flow and load gain tests, by sending the different types of frame, of variable length; the possibility of recording and personalizing the tests carried out; the possibility of downloading software or drivers for updating the software internal to the box; the possibility of starting and extinguishing quickly.

Claims

1 / Test device (15), making it possible to analyze the quality of the connection to an access point (1) of a wireless local area network, from a place capable of accommodating computer equipment (10 ) including a wireless communication card (11), characterized in that it is in the form of a box comprising:

- a housing (9) adapted to receive interchangeably a wireless communication card (16);

- means for processing signals sent and / or received to and / or from the access point (2) to the network (1); display means (17) for information relating to said signals.

2. Test apparatus according to claim 1, characterized in that the housing (19) is capable of receiving wireless communication cards (16), of the PCMCIA type.

3. Test apparatus according to claim 1, characterized in that the processing means are capable of controlling the operation of the wireless communications card, according to a program or pilot, selected from a predetermined list.

4. Test apparatus according to claim 3, characterized in that it comprises means for updating the predefined list of pilots.

5. Test apparatus according to claim 1, characterized in that it comprises recording and information means relating to the signals transmitted and / or received to and / or from the access point (2) at network.

6. Test apparatus according to claim 1, characterized in that it comprises means for transferring (21) to the computer information relating to the signals transmitted and / or received to and / or from the point d access to the network.

7. Test apparatus according to claim 1, characterized in that the processing means are capable of transmitting data packets or frames according to a protocol compatible with the wireless local area network.

8. Test apparatus according to claim 7, characterized in that the processing means are capable of transmitting frames of different lengths.

9. Test apparatus according to claim 8, characterized in that the length of the frames is configurable by the user.

10. Test apparatus according to claim 9, characterized in that the transmission time of the frames is configurable by the user.

11. An assembly comprising a test apparatus according to one of claims 1 to 10 and at least one equipment capable of receiving and transmitting signals transmitted and received from and to said apparatus, and playing the role of access point to the network.

12. Assembly comprising a test device according to one of claims 1 to 10 and at least one equipment able to receive and transmit signals transmitted and received from and to the access point (2) to the network (1) , said equipment playing the role of computer equipment connected to the network.