User's Manual

!AcroLAN Card User’s Guide Version 20002.5

Page 5 of 38

Electrical and Electronics Engineers (IEEE) ratified the original 802.11 specifications in

1997 as the standard for wireless LANs. That version of 802.11 provides for 1 Mbps and

2 Mbps data rates and a set of fundamental signaling methods and other services. The

most critical issue affecting WLAN demand has been limited throughput. The data rates

supported by the original 802.11 standard are too slow to support most general business

requirements and have slowed adoption of WLANs. Recognizing the critical need to

support higher data-transmission rates, the IEEE recently ratified the 802.11b standard

(also known as 802.11 High Rate) for transmissions of up to 11 Mbps.

With 802.11b, WLANs will be able to achieve wireless performance and throughput

comparable to wired Ethernet. Outside of the standards bodies, wireless industry leaders

have united to form the Wire-less Ethernet Compatibility Alliance (WECA).

WECA’s mission is to certify cross-vendor interoperability and compatibility of IEEE

802.11b wireless networking products and to promote that standard for the enterprise,

the small business, and the home. Members include WLAN semiconductor

manufacturers, WLAN providers, computer system vendors, and software makers.

ƒƒ

ƒ Wireless LAN Network Equipment

802.11 defines two pieces of equipment, a wireless station, which is usually a PC

equipped with a wireless network interface card (NIC), and an access point (AP), which

acts as a bridge between the wireless and wired networks. An access point usually

consists of a radio, a wired network interface (e.g., 802.3), and bridging software

conforming to the 802.1d bridging standard. The access point acts as the base station

for the wireless network, aggregating access for multiple wireless stations onto the wired

network. Wireless end stations can be 802.11 PC Card, PCI.

ƒƒ

ƒ Wireless LAN Network Configuration

The 802.11 standard define two modes: infrastructure mode and ad hoc mode (or

independent or peer-to-peer).

l Ad Hoc Mode

Ad hoc mode (also called peer-to-peer mode or an Independent Basic

Service Set, or IBSS) is simply a set of 802.11 wireless stations that

communicate directly with one another without using an access point or any

connection to a wired network. This mode is useful for quickly and easily

setting up a wireless network anywhere that a wireless infrastructure does not

exist or is not required for services, such as a hotel room, convention center,

or airport, or where access to the wired network is barred (such as for

consultants at a client site).

Independent Basic

Service Set (IBSS)