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Enterprise Telecom Services

How to Set Up A Wireless LAN

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Voice&Data Bureau
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Wireless LAN (WLAN) is a data transmission system designed to provide a
location independent network access between the various computing devices, by
using radio waves, rather than a cable infrastructure. In the present scenario,
WLANs are usually implemented as the final link between the existing wired
networks and a group of client computers, giving these users access to the full
resources and services of the corporate network, across a building or a campus
setting, without the use of cable.

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WLANs offer a variety of benefits over the traditional wired networks,
including productivity, convenience and cost advantages. These are highly mobile
and provide access to real-time information, anywhere in the building. These
networks are simple, fast and easy to install. Moreover, they provide the
flexibility of taking the network where wires are difficult to pull. While the
initial cost of installation of the hardware for WLANs may be higher than the
wired LAN, the total cost of ownership is significantly lower, because WLANs
eliminate direct costs of cabling and the labor associated with installation and
repair.

Step 1: Technology Selection

Wireless technology uses radio waves to transmit data. There are several
types of technologies used for data transmission. The appropriate technology for
a given situation depends on the specific needs of the client. The various types
of technologies are:

  • n Spread-spectrum
    technology: Wireless products most commonly use spread-spectrum technology
    for data transmission. The spread-spectrum technology consumes more
    bandwidth than other technologies, in order to assure high reliability,
    integrity and security. In other words, the signal produced by the
    spread-spectrum is "louder" than that of other technologies.

  • n Narrowband
    technology: A narrow-band radio system transmits and receives user
    information on a specific radio frequency. The radio signal frequency is
    kept as narrow as possible to minimize costs, through a simple radio design.
    The narrowband technology has a limited range, reliability and security, as
    compared to the spread-spectrum technology.

  • n Infrared
    technology: Infrared (IR) systems use very high frequencies in the
    electromagnetic spectrum, to carry the data. Like light, infrared cannot
    penetrate through opaque objects. This technology has a limited range and
    lower throughput, as compared to the direct sequence spread-spectrum.

  • n Microwave
    technology: Microwave technology uses low microwave frequencies that allow
    for range and throughput rates in between those of infrared and
    spread-spectrum technologies. Microwave works best with a clear
    line-of-sight. The FCC licensing is required for the microwave WLANs,
    operating between 18.8 GHz and 19.2 GHz. Line-of-sight and FCC licensing
    limitations, coupled with high costs and safety concerns, have inhibited the
    growth of microwave technology.

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Step 2: Types of Wireless LANs

A Wireless LAN is comprised of Network Interface Cards (NICs),
Access points and Network management. The WLAN configurations can be simple or
complex. There are two basic types of WLANs:

  • Peer-to-peer
    WLANs

  • Infrastructure
    WLANs

Step 3a: Setting up a peer-to-peer WLAN

You only require wireless adapters on each PC, to establish a
peer-to-peer WLAN.

  1. Assess how many
    PCs need to be connected to the WLAN.

  2. Equip each PC
    with the wireless.

  3. Configure the NIC
    setting on each PC.

  4. Whenever the PCs
    come within range of each other, they establish an independent network
    between themselves, allowing each to access the resources and information of
    the other.

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Step 3b: Setting up an infrastructure WLAN

In infrastructure WLANs, the WLAN is linked to the wired
network, thereby allowing the users to efficiently share the network resources.

  1. Site Survey:
    The network manager should conduct a site survey. Some vendors offer a site
    survey utility with their products, which use signal strength and packet
    error information to help them determine where to place the access points,
    for the best coverage. A typical range of the access point is 500 ft indoor
    and 1000 ft outdoor. The throughput is affected by the number of reflective
    surfaces, walls and type of the technology in use for data transmission.
    Each access point has an area of coverage associated with it. This area of
    coverage is called "microcell". The site survey should ensure that
    individual microcells overlap to allow continuous communication within the
    wired network.

  2. Creating the
    WLAN    : The next step is to connect the access points. The access point is
    connected through a single cable to the wired network, which allows it to
    access the information and resources available on the wired network. Each PC
    to be connected to the WLAN has to be equipped with a wireless adapter or a
    NIC, which gives these PCs the ability to connect to the access point
    through the transmission of radio waves, instead of the cables. All PCs that
    are within the microcell of the access point get connected to the wired
    network without NIC use of the cable, thus creating a WLAN.

  3. Managing the
    WLAN    : Most WLAN solutions come with relatively simple management tools
    that leverage existing network management platforms to monitor and manage a
    variety of networking and radio variables. The network managers can use the
    web-based management tools to manage the access points from anywhere on the
    network and configure, monitor or change the configuration of the access
    points.

  4. Extending the
    WLAN    : In the areas where two WLANs are to be connected and the distance
    is more than a mile, the network managers have the option of using
    directional antenna. For this purpose, a directional antenna is placed at
    each location targeting towards the other location. The antenna is linked to
    an access point, which allows each location to share the information and
    resources of the other.

Step 4: Security Aspects

WLANs have their roots in military technology, therefore
security has been an important priority. In fact, it is extremely difficult for
unintended receivers to listen in on WLAN traffic.

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A WLAN solution can support multiple layers of security. In
order to gain access to the network, the network ID of the access points must be
known. Once a user is associated with an access point, they have the same
security provided on the wired network i.e. authentication of the login ID, the
password, and so on. In addition, the Wired Equivalent Privacy (WEP)–a
standard based security protocol for wireless networks may be enabled to provide
further security.

For some products, WLAN products offer multiple layers of
security, which include access point locking, user authentication, domain
identification, spread-spectrum technology and an option to scramble wireless
data transmissions using encryption.

With the recent adoption of new standards for high-rate WLANs,
mobile users can realize levels of performance, throughput and availability,
comparable to those of the traditional wired Ethernet.

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Angelina Alfred, senior executive, marketing services,
3Com India Ltd.