Table of Contents
Advertisement
13 | Frequently Asked Questions
What is a Wireless LAN?
A local area network that transmits over the air typically in an unlicensed frequency such as the
2.4GHz band. A wireless LAN does not require lining up devices for line of sight transmission like
IrDA. Wireless access points (base stations) are connected to an Ethernet hub or server and
transmit a radio frequency over an area of several hundred to a thousand feet which can
penetrate walls and other non-metal barriers. Roaming users can be handed off from one access
point to another like a cellular phone system. Laptops use wireless network cards that plug into
an existing PCMCIA slot or that are self contained on PC cards, while stand-alone desktops and
servers use plug-in cards (ISA, PCI, etc.).
What is AD- HOC?
An AD-HOC network is a peer to peer network where all the nodes are wireless clients. As an
example, two PC's with wireless adapters can communicate with each other as long as they are
within range. A wireless extension point can extend the range of an AD-HOC network.
What is the 802.11 standard?
A family of IEEE standards for wireless LANs first introduced in 1997. 802.11 provides 1 or 2
Mbps transmission in the 2.4GHz band using either a frequency hopping modulation (FHSS)
technique or direct sequence spread spectrum (DSSS), which is also known as CDMA. The
802.11b standard defines an 11 Mbps data rate in the 2.4GHz band, 802.11g-draft standard
defines 54 Mbps in the 2.4GHz band, and the 802.11a standard defines 54 Mbps in the 5GHz
band.
What is Infrastructure?
In order for your wireless components to interact with traditional wired networks they need a
media bridge to translate for them. This is where INFRASTRUCTURE or Network mode comes
into play. An ACCESS POINT is attached to the network using CAT-5 Ethernet cable attaching to
a hub, switch or another PC. Wireless PC's can then communicate to Wired Ethernet computers
through this access point. The total range of the network is limited to a radius around this Access
Point. To increase the range, extra Access Points may be wired into the network. These Access
Points talk to each other over the hard-wired Ethernet cables however, they cannot communicate
wirelessly to one another and they must be wired to the same network. Individual wireless PC's
can move between Access Points on the same network seamlessly due to a feature called
ROAMING.
What is Tx Rate?
Advertisement
Table of Contents
