# Introduction to Wireless Networking

Intel® PRO/Wireless LAN net products, including the Intel® PRO/Wireless 2011B LAN product, are based on the IEEE 802.11b specification and connect computers together to form a wireless network.

A Local Area Network (LAN) is a network in a limited area. In a LAN, networked computers are called clients, and servers provide requested services, such as file delivery and printing. In a wireless LAN (WLAN), wireless adapters are installed in clients to communicate with servers and each other. A wireless client communicates with the WLAN through radio waves instead of cables.

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 data to the access point. The access point receives the information and rebroadcasts it to other devices.

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 wider area. Access points can connect to a LAN through a wired Ethernet connection to send and receive information.

## 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. In software and documentation, the terms SSID and Extended Service Set Identifier (ESSID) are used interchangeably.

## 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 to implement security and protect 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.

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.

The IEEE 802.11 wireless LAN specification specifies the Wired Equivalent Privacy (WEP) encryption and decryption algorithm. The specification includes two levels of security, using a 40-bit key or a 128-bit key. To implement WEP, use either one of these methods. For better security, use a 128-bit key. A 128-bit key has several trillion times as many possible combinations as a 40-bit key. For added security, change your keys often. Some vendors refer to 40-bit encryption as 64-bit. These are identical. A wireless device that claims to have 40-bit encryption interoperates with a device that claims to have 64-bit encryption.

The software for an Intel PRO/Wireless LAN Adapter includes Intel PROSet II. In this software, you can use a passphrase to generate a 128-bit encryption key.

## Adapter Features

Adapter features include:

- IEEE 802.11b specification compatibility. This open architecture allows Intel® PRO/Wireless 2011B LAN devices to communicate with wireless devices from other vendors.
- 11 Mbps data rate for high-capacity, fast operation.
- Standard Network Driver Interface Specification (NDIS).
- Microsoft Windows* 95, Windows 98, Windows 2000, and Windows CE driver support.
- Card and Socket Services support.
- WEP data security.
- Plug and Play support.
- Operating range of about 45 meters (150 feet).
- Low-power operation for battery-powered devices with PC Card slots. Power management includes Continuously Aware Mode (CAM) and Power Save Polling (PSP).
- Peer-to-peer mode for connecting directly to other computers.
- Station mode for use with single or multiple access points.
- Roaming support for mobile LAN connections throughout large facilities.

The adapter can only be installed in a PC Card slot in a suitably equipped computer. The adapter contains a built-in radio antenna that protrudes when inserted into the slot.

The Intel PRO/Wireless 2011B LAN Adapter allows Personal Computer Memory Card International Association (PCMCIA) 3.3-volt Type II slot-equipped computers to connect to an Intel PRO/Wireless 2011B LAN network.

The exposed end of the adapter is vulnerable to damage from scratching, snagging or striking other objects. Such contact may bend or break the adapter or the PC Card slot in which it resides.

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