Wireless LAN network is one of the fastest growing computer tasks today—and with good reason. Networking your computers with wireless equipment is simple and makes your equipment more useful and portable.
Wireless LAN network refers to connecting two or more computers to create a local area network (LAN) using radio transmitter/receivers (sometimes called transceivers). The computers transmit data via radio waves, which allows the sharing printers, documents, and share Internet access on every computer in the network. You can move the components of your wireless LAN network without losing your connection to the network.
Benefits of Wireless Networking
Wireless LAN network offers some benefits that are apparent (no wires) and some that you might not have considered. The most obvious is portability. In particular, if you set up a laptop for wireless networking, you can roam around your house or around a coffee shop.
Wireless Networking Topologies
In computer networking, the term topology typically refers to the pattern of the cables used to connect the computers. Wireless LAN network does not use cables, but they still have a topology, which defines how the wireless devices interact at the physical layer. At the physical layer, IEEE 802.11b Wireless LAN uses direct sequence spread spectrum communications at a frequency of 2.4 GHz, and the devices can communicate with each other using two basic topologies: ad hoc and infrastructure.
Ad Hoc Network
Wireless Network - Ad -Hoc
An ad hoc network consists of two or more wireless devices communicating directly with each other. The signals generated by Wireless LAN network interface adapters are Omni-directional out to a range that is governed by environmental factors, as well as the nature of the equipment involved. This range is called a basic service area (BSA). When two wireless devices come within range of each other, they are able to connect and communicate, immediately forming a two-node network. Wireless devices within the same basic service area are called a basic service set (BSS).
Other wireless devices coming within the transmission range of the first two can also participate in the network. Ad hoc networking is not transitive, however. A wireless device that comes within range of another device, but still lies outside the range of a third, can only communicate with the device in its range.
Infrastructure Network
Wireless Network Infrastructure
An infrastructure network uses a wireless device called an access point as a bridge between wireless devices and a standard cabled network. An access point is a small unit that connects to an Ethernet network (or other cabled network) by cable, but that also contains an 802.11b-compliant wireless transceiver. Other wireless devices coming within range of the access point are able to communicate with the cabled network, just as though they were connected by a cable themselves. The access point functions as a transparent bridge, effectively extending the cabled local area network (LAN) to include the wireless devices.
On an infrastructure network, wireless devices communicate only with the access point; they do not communicate with each other directly. Therefore, even if two wireless computers are within range of each other, they must still use the access point to communicate.
There are a number of wireless technologies on the market today which leverage many different wireless standards. Today’s shared Wireless LAN Network technologies can now offer flexible connectivity options at 108 Mbps or greater speeds up to 300 Mbps and support unobstructed distances of up to 500 meters.
The chief concern for deploying Wireless LAN Networks is security. Since Wireless LAN Network broadcasts data over the air using radio waves (electromagnetic frequencies), virtually any wireless LAN client in the vicinity served by the transmitter can access the communication media. This makes it potentially very easy to eavesdrop conversations and gain access to a private network via wireless access points.
If wireless LAN technology is to be deployed it must support the necessary security requirements, including strong encryption. This should include a security policy educating users not to illegally connect Wireless LAN Network to the internal network.
This technology and its security limitations should be researched and piloted before being implemented to identify these risks.
The minimum requirement with regards to Wireless LAN Network is:
- Wi-Fi certified IEEE 802.11G wireless products are to be only used.
- Wireless access points must not be over sub-scribed.
- All wireless network access points must be secure and only accept authorized encrypted data.
- A strong encryption protocol with dynamic keys must be used to access the wireless LAN Network.
The recommended requirement with regards to Wireless LAN Network is:
- As above plus the following
- All wireless access points must be securely located on a separate firewalled network segment to the internal network.
- A suitable firewall security policy must be used to restrict access to the internal LAN.
- A wireless map of the network must be undertaken to define the boundaries and performance characteristics of the Wireless LAN network
Clients use radio and/or microwave based frequencies to connect to the private network via a wireless network card in the PC. This wireless network card communicates with a wireless access point located in close proximity to the PC client. Due to the multi-access nature of wireless LAN Network only shared bandwidth is allowed, while policies such as Quality of Service (QoS) and IP multicast cannot be fully supported.
The main wireless protocol today is IEEE 802.11G which is an extension to the original slower IEEE 802.11 standard. Another developing wireless standard is draft 2.0 IEEE 802.1n which will deliver up to 300 Mbps and offers to maintain compatibility with 802.1b/g certified equipment.
Wireless LAN products that carry the Wi-Fi logo are fully IEEE 802.11b compliant and have been certified by the Wireless Ethernet Compatibility Alliance (WECA).
The Wi-Fi specification defines a global, wireless LAN standard which will interoperate with other Wi-Fi certified products.
While wireless LAN network gives transparent network access to the roaming user, they do open the network up to many security risks. The radio frequency can easily leak up to 500 meters (or more) from the immediate area of the network access point. Encryption protocols such as Wired Equivalent Privacy (WEP) can be used to secure wireless LANs. The use of dynamic keys with WEP can be used to address known security limitations of the 802.11b WEP protocol. The newest industrial wireless connection security is Wi-Fi Protected Access (WPA/WPA2).
To further secure wireless LAN network it is strongly recommended that wireless access points be secured on a separate fire-walled network segment. A suitable security policy (including strong encryption) must be enforced to reduce the threat of network security violations. Because wireless LAN network is an emerging technology ongoing security analysis is required. Users must be educated in not setting up island wireless networks that circumvent any wireless security policy.
By implementing a wireless LAN network without any forms of network security is extremely dangerous. It potentially allows external unauthorized users to readily gain access to the internal network via wireless access points. Wireless LANs must be encrypted and the risk associated by outside access must be addressed.
Due to the shared nature of the wireless media Quality of Service (QoS) and bandwidth limitations exist. In order to deliver any QoS priority data (i.e. realtime voice or video) the shared wireless segment must remain under-subscribed. Even in this case application performance may be unreliable
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