# Introduction to Wireless Networking

The Intel® PRO/Wireless 5000 LAN Adapter is an Intel® PRO/Wireless 5000 LAN network product. Intel® PRO/Wireless 5000 LAN network products are based on the IEEE 802.11a standard and connect computers together to form a wireless network. Intel® PRO/Wireless 5000 LAN Adapters offer 54 Mbps data rates using clean spectrum 5 GHz transmissions.

A Local Area Network (LAN) is a network in a central location. Users at that location share files, printers, and other services. In a LAN, a networked computers that request services are called clients, while servers in a LAN provide services. In a wireless LAN (WLAN), wireless adapters are installed in clients. A wireless client communicates with the WLAN without cables. Instead, wireless clients send and receive information through the air.

A wireless client operates in either infrastructure mode or peer-to-peer mode.

## Infrastructure Mode: A WLAN with Access Points

In infrastructure mode, wireless clients send and receive information through access points. When a wireless client communicates with another, it transmits to the access point. The access point receives the information and rebroadcasts it. Then the other device receives the information.

Access points are strategically located within an area to provide optimal coverage for wireless clients. A large WLAN uses multiple access points to provide coverage over a wide area. Access points can connect to a LAN through a wired Ethernet connection. Access points send and receive information from the LAN through this wired connection.

## Peer-to-Peer Mode: A WLAN without Access Points

In peer-to-peer mode, also called Ad Hoc Mode, wireless clients send and receive information to other wireless clients without using an access point. In contrast to infrastructure mode, this type of WLAN only contains wireless clients.

You can use peer-to-peer mode to network computers in a home or small office, or to set up a temporary wireless network for a meeting.

## Identifying a WLAN

All adapters and access points in a WLAN use a Network Name, or Service Set Identifier (SSID) to identify the WLAN. The SSID indicates what WLAN you are communicating with.

## Wireless Security

Wireless networking devices transmit information through the air. Without implementing security, it is easy for an unauthorized person to intercept the information.

A common way of implementing security and protecting information is encryption. Before sending information, the wireless client or access point encrypts or scrambles information using an encryption key. The device receiving the information uses the same key to decrypt or unscramble the information. The information is only readable to wireless devices that have the correct encryption key.

### 64-bit or 128-bit security

The IEEE 802.11 wireless LAN standard specifies the Wired Equivalent Privacy (WEP) encryption and decryption algorithm. The standard includes two levels of security, using a 64-bit key or a 128-bit key. Some vendors refer to 64-bit encryption as 40-bit. These are identical. A wireless device that claims to have 64-bit encryption interoperates with a device that claims to have 40-bit encryption.

To implement WEP, use either the 64-bit or 128-bit method. For better security, use a 128-bit key. A 128-bit key has several trillion times as many possible combinations as a 64-bit key. For added security, change your keys often.

The same device, host computer or front-end processor usually performs both encryption and decryption. The algorithm, like the pattern of a lock, is standardized and may be used by anyone, but the encrypted data is unreadable without the appropriate key, which is known only by the sender and receiver of the transmitted data. You should change your keys often for added security.

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