User manual

www.modecom.eu
5
2. Wireless Network Concepts
For the past few decades, wired Local Area Networks (LAN) or more commonly know as Ethernet, have provi-
ded a seamless way of connecting and communicating with multiple PCs, desktops, laptop/notebooks, servers
as well as a host of other peripherals, including printers, scanners, etc. LANs have served us well in environ-
ments where users were not mobile or had little need to access data other than in their office.
With the advent of notebook computers and an increasingly mobile computing society, the need for wireless
networking finds more applications with each passing day. Wireless LANs have evolved to meet the needs of
mobile computing and are becoming very popular as compatibility, reliability and familiarity increases and
equipment costs decrease.
Wireless LANs (WLAN) allow users to roam freely about a network taking their computers with them while
still maintaining a networking connection. In essence, WLANs are an extension of wired LAN networks, where
the critical need is data access and mobility. The tradeoffs are slower speeds (although quite satisfactory for
Internet and email access) and limited roaming distance, as dictated by the environment.
A basic WLAN network requires client nodes and access points, similar to a LAN with its clients and infrastructu-
re (switches, repeaters, etc.). The access point is the connection to the wired LAN network or a designated com-
puter device performing the supervisory function, while client nodes are typically WLAN adapters installed
in peripheral computing devices, such as notebooks, desktops, personal digital assistants (PDAs) and others.
Once a WLAN is setup, it acts like a wired LAN, using the same protocols designated for communicating via the
IEEE Ethernet standard.
2.1 Wireless LAN Network Modes
WLANs basically have two modes of operation:
• Ad-Hoc mode
• Infrastructure mode
Ad-Hoc Mode
An Ad-Hoc WLAN is created when two or more PCs equipped with Wireless LAN Cards (WLAN clients) are con-
figured to use the same radio channel and Network Name in the same area and can communicate freely with
each other, without the need for an Access Point to a hard-wired LAN network. Only PCs that use the same ra-
dio channel and network name can communicate over the Ad-Hoc network. This type of a network is a peer-to-
-peer relationship where each computer talks directly to one another with no one PC being dominant.