How to Set Up A Wireless LAN

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.

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.

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.

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.

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.

Angelina Alfred, senior executive, marketing services,

3Com India Ltd.