10-07-2012, 03:50 PM
Basic Wireless Technology
[attachment=27382]
Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves for the carrier.
Wireless LAN
Wireless LANs (WLANs) use radio frequencies (RFs) that are radiated into the air from an antenna that creates radio waves. These waves can be absorbed, refracted, or reflected by walls, water, and metal surfaces, resulting in low signal strength.
When we move into the WLAN environment, we move our transmission methods to a collision avoidance (CSMA/CA) strategy because wireless devices have no collision detection mechanism. Likewise, because a wireless device that is sending data cannot receive data at the same time, WLAN devices run at half duplex as a rule.
Infrastructure Topology
This involves using a dedicated piece of equipment (typically a wireless access point) to initiate and manage the wireless network. Wireless access points can be configured to use one of two infrastructure modes: Basic Service Set (BSS) or Extended Service Set (ESS).
The BSS is the simplest form of wireless network. It includes a single wireless access point managing a group of clients.
An ESS is a wireless topology that includes two or more wireless access points providing extended wireless coverage across the network.
Mobility
wireless LANs cannot replace wired LANs in terms of data rates (100BT at 100Mbps versus IEEE 802.11a at 54Mbps). What wireless LANs do offer is an increase in mobility (as seen in Figure ) as the trade off for speed and quality of service.
Small Office-Home Office
As an IT professional, you may have more than one computer at your home. And if you do, these computers are most likely networked together so you can share files, a printer, or a broadband connection.
[attachment=27382]
Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves for the carrier.
Wireless LAN
Wireless LANs (WLANs) use radio frequencies (RFs) that are radiated into the air from an antenna that creates radio waves. These waves can be absorbed, refracted, or reflected by walls, water, and metal surfaces, resulting in low signal strength.
When we move into the WLAN environment, we move our transmission methods to a collision avoidance (CSMA/CA) strategy because wireless devices have no collision detection mechanism. Likewise, because a wireless device that is sending data cannot receive data at the same time, WLAN devices run at half duplex as a rule.
Infrastructure Topology
This involves using a dedicated piece of equipment (typically a wireless access point) to initiate and manage the wireless network. Wireless access points can be configured to use one of two infrastructure modes: Basic Service Set (BSS) or Extended Service Set (ESS).
The BSS is the simplest form of wireless network. It includes a single wireless access point managing a group of clients.
An ESS is a wireless topology that includes two or more wireless access points providing extended wireless coverage across the network.
Mobility
wireless LANs cannot replace wired LANs in terms of data rates (100BT at 100Mbps versus IEEE 802.11a at 54Mbps). What wireless LANs do offer is an increase in mobility (as seen in Figure ) as the trade off for speed and quality of service.
Small Office-Home Office
As an IT professional, you may have more than one computer at your home. And if you do, these computers are most likely networked together so you can share files, a printer, or a broadband connection.