What Is Wireless Networking?
The term wireless networking refers to technology that enables two or more computers to communicate using standard network protocols, but without network cabling. Strictly speaking, any technology that does this could be called wireless networking. The current buzzword however generally refers to wireless LANs. This technology, fuelled by the emergence of cross-vendor industry standards such as IEEE 802.11 (in the form of 802.11b and 802.11a), has produced a number of affordable wireless solutions that are growing in popularity with homes, business and schools as well as sophisticated applications where network wiring is impossible, such as in warehousing or point-of-sale handheld equipment.

General Rules of Thumb - Compatibility
802.11b networks are interchangeable - both 11Mbps and 22Mbps versions.
802.11a networks are NOT compatible with 802.11b devices.
802.11a uses the 5GHz spectrum and 802.11b uses the 2.4GHz spectrum.

What is a wireless network made up of?
There are two kinds of wireless networks:

Ad-Hoc or Peer-to-Peer Networking.
An ad-hoc, or peer-to-peer wireless network consists of a number of computers each equipped with a wireless networking interface card. Each computer can communicate directly with all of the other wireless enabled computers. They can share files and printers this way, but may not be able to access wired LAN resources, unless one of the computers acts as a bridge to the wired LAN using special software and/or additional hardware to connect to the wired LAN.

Infrastructure Networking.
A wireless network can also use an access point, or base station. In this type of network the access point acts like a hub, providing connectivity for the wireless computers. It can connect the wireless LAN to a wired LAN, allowing wireless computer access to LAN resources, such as file servers or existing Internet Connectivity.

There are two types of access points:

Dedicated Hardware Access Points (HAP) such as 3Com's AirConnect, offer comprehensive support of wireless features, and are usually used as an extension of a wired network, providing additional access in remote areas, or providing for a mobile workforce.

Integrated Access Points, include features not commonly found in access points, such as integrated PPPoE support and extensive configuration flexibility. Generally they provide both wired and wireless access in one unit. With appropriate networking support, users on the wireless LAN can share files and printers located on the wired LAN and vice versa. All current configurations provide total support of the TCP/IP protocol.

Hardware Access Point.
Wireless connected computers using a Hardware Access Point.


Integrated Access Point.
Wireless connected computers using a Integrated Access Point.

What is IEEE 802.11?
Wireless networking hardware requires the use of underlying technology that deals with radio frequencies as well as data transmission. The most widely used standard is 802.11 produced by the Institute of Electrical and Electronic Engineers (IEEE). There have been two standards which have emerged - 802.11b, the most popular and widely used standard which provides networking for up to 1000 feet (outdoors) and a rated maximum bandwidth of 22 Mbps and 802.11a, currently being released as a more robust and high-bandwidth (72Mbps maximum rating) specification for commercial and industrial usage.

Can I mix wireless equipment from different manufacturers?
Because most wireless networking hardware vendors support the 802.11b standard they can interoperate. Within a short time we have seen all new wireless cards, like ethernet cards, become inexpensive, ubiquitous and totally interoperable. Note that the two 802.11 standards -- "a" and "b" are NOT interoperable.

What is the range of a wireless network?
Each access point has a finite range within which a wireless connection can be maintained between the client computer and the access point. The actual distance varies depending upon the environment; manufacturers typically state both indoor and outdoor ranges to give a reasonable indication of reliable performance. Also it should be noted that when operating at the limits of range the performance may drop, as the quality of connection deteriorates and the system compensates.

Typical indoor ranges are 150-300 feet, but can be shorter if the building construction interferes with radio transmissions. Longer ranges are possible, but performance will degrade with distance.

Outdoor ranges are quoted up to 1000 feet, but again this depends upon the environment.

There are ways to extend the basic operating range of Wireless communications, by using more than a single access point or using a wireless relay /extension point.

How many wireless networked computers can use a single access point?
This depends upon the manufacturer. Some hardware access points limit to 10, however newer models will support up to 255 wireless connections. Using more computers than recommended will cause performance and reliability to suffer.

Can I have more than one access point?
Yes, multiple access points can be connected to a wired LAN, or sometimes even to a second wireless LAN if the access point supports this.

In most cases, separate access points are interconnected via a wired LAN, providing wireless connectivity in specific areas such as offices or classrooms, but connected to a main wired LAN for access to network resources, such as file servers.

Multiple Access Points.
Wireless connected computers using Multiple Access Points.

If a single area is too large to be covered by a single access point, then multiple access points can be used. When using multiple access points, each access point wireless area should overlap its neighbors. This provides a seamless area for users to move around in using a feature called "roaming."

What is Roaming?
A wireless computer can "roam" from one access point to another, with the software and hardware maintaining a steady network connection by monitoring the signal strength from in-range access points and locking on to the one with the best quality. Usually this is completely transparent to the user; they are not aware that a different access point is being used from area to area.

Access points are required to have overlapping wireless areas to achieve this as can be seen in the following diagram:

Roaming.
A user can move from Area 1 to Area 2 transparently. The Wireless networking hardware automatically swaps to the Access Point with the best signal.


Not all access points are capable of being configured to support roaming. Also of note is that any access points for a single vendor should be used when implementing roaming, as there is no official standard for this feature.

Can I use a wireless network to interconnect two LANs?

Yes. Wireless networking offers a cost-effective solution to users with difficult physical installations such as campuses, hospitals or businesses with more than one location in immediate proximity but separated by public thoroughfare. This type of installation requires two access points. Each access point acts as a bridge or router connecting its own LAN to the wireless connection. The wireless connection allows the two access points to communicate with each other, and therefore interconnect the two LAN's.
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Is it true that wireless networking is only good for laptop computers?
Although wireless networking offers obvious benefits to users of laptops who move from location to location throughout the day, there are benefits for users of fixed position computers as well:

Many locations have unsuitable building layouts or walls that cannot be wired for various reasons making it difficult or impossible to build a wired network. Wireless networking in these environments is a very cost effective alternative also providing future flexibility.

In cases where a small number of computers are separated from a main network a wireless link may be more cost effective than network cabling although the latter is perfectly feasible.

Temporary wireless LANs can easily be created for exhibitions, school or business projects, all without any trailing cabling.

What about security?

Wireless communications obviously provide potential security issues, as an intruder does not need physical access to the traditional wired network in order to gain access to data communications. However, 802.11 wireless communications cannot be received --much less decoded-- by simple scanners, short wave receivers etc. This has led to the common misconception that wireless communications cannot be eavesdropped at all. However, eavesdropping is possible using specialized equipment.

To protect against any potential security issues, 802.11 wireless communications have a function called WEP (Wired Equivalent Privacy), a form of encryption which provides privacy comparable to that of a traditional wired network. If the wireless network has information that should be secure then WEP should be used, ensuring the data is protected at traditional wired network levels. This security protocol is available in 40 bit to 512 bit encryption. Most all accesspoint and interface providers offer these protocols.