16-10-2012, 04:56 PM
Wireless Local Area Networks(WLANs)
local area network (LAN) market.docx (Size: 775.86 KB / Downloads: 23)
Introduction
Today wireless is becoming the leader in communication choices among users. The past few years, WLAN’s have gained very great place in the local area network (LAN) market. Today WLAN’s based on IEEE 802.11 standard constitute a practical and interesting solution of network connection offering mobility, flexibility ,low cost of deployment and use .
Wi-Fi is a trademark of the Wi-Fi Alliance, founded in 1999 as WECA(Wireless Ethernet Compatibility Alliance).The organization comprises more than 300 companies ,whose products are certified by the Wi-Fi Alliance ,based on the IEEE 802.11 standards(also called Wireless LAN (WLAN)and Wi-Fi ).This certification warrants interoperability between different wireless devices.
Wi-Fi networks are rapidly becoming common in coffee shops, hotels, convention centers, airport, libraries and community areas, anyplace where people gather. In these locations, a Wi-Fi network can provide internet access to guest and visitors. People can connect using their own Wi-Fi equipped laptop computers and portable computing device. Foreigners, business professionals and young people are using Wi-Fi equipped laptop computers and portable computing device. These people are looking to be able to use their Wi-Fi equipped device in coffee shops, hotels, convention centers, airport, libraries and community areas and other. That’s why I’m going to propose a simple Wi-Fi network for a shopping mall.
What is Wireless Local Area Networks(WLANs)
When the first personal computers appeared in the late 1970s, they were meant to be placed on a desk. However, with the advent of laptop computers in the 1980s, and handheld computers in the 1990s, people began using these devices in airplanes, automobiles, or outside. This new mobility presented new problems when the Internet became widely used in the mid-1990s. People wanted to access the Internet wherever they were.
As a solution, engineers proposed connecting computers to the Internet through a wireless radio link rather than ordinary wires—a Wireless Local Area Network or WLAN. WLANs, which use microwave radio, have a mobile station and at least one fixed station that connect all mobile laptops within a network
WLANs have become so successful that today they are installed in offices to allow workers to carry their computers from place to place inside buildings. WLANs are also being installed on college campuses to allow students and faculty to freely move about with their computers, and in homes to avoid costly and unsightly network wires in walls.
In a typical business office WLAN system, the controlling wireless unit is normally mounted in a central hallway and is called an Access Point (AP) radio. Several of these APs are usually located in a building to give good coverage to all offices.
This same concept applies to a home network where one access point is usually sufficient. A centrally controlled access point radio is connected to a high data rate wired Local Area Network (LAN) that can take the data from many computers to a centrally located server computer and then on to the Internet.
Why wireless architecture?
Introduction
Wired and wireless networks each have advantages and disadvantages. Wired networks provide users with plenty of security and the ability to move lots of data very quickly. Wired networks are typically faster than wireless networks, and they can be very affordable. However, the cost of Ethernet cable can add up -- the more computers on your network and the farther apart they are, the more expensive your network will be. In addition, unless you're building a new house and installing Ethernet cable in the walls, you'll be able to see the cables running from place to place around your home, and wires can greatly limit your mobility. A laptop owner, for example, won't be able to move around easily if his computer is tethered to the wall.
Wired network architecture
Wired network
A wired network is one in which all the components are connected with network cable. If different devices are spread out, network cable will have to be run from the router to the device.
Wired LANs use Ethernet cables and network adapters. Although two computers can be directly wired to each other using an Ethernet crossover cable, wired LANs generally also require central devices like hubs, switches, or routers to accommodate more computers.
Wireless network architecture
Wireless network
In a wireless network everything is connected without any wires by radio waves. The only exception is the wire from your ISP to your broadband modem and from there to your router.
Why we moved into wireless instead of wired network architecture
Benefits of a Wireless Network
Wireless LANs offer the following productivity, convenience, and cost advantages over wired networks:
Mobility
Wireless LAN systems can provide LAN users with access to real-time information anywhere in their organization. This mobility supports productivity and service opportunities not possible with wired networks.
There are now thousands of universities, hotels and public places with public wireless connection. These free you from having to be at home or at work to access the Internet.
Installation Speed and Simplicity
Installing a wireless LAN system can be fast and easy and can eliminate the need to pull cable through walls and ceilings.
Cost savings
While the initial investment required for wireless LAN hardware can be higher than the cost of wired LAN hardware, overall installation expenses and life-cycle costs can be significantly lower. Long-term cost benefits are greatest in dynamic environments requiring frequent moves and changes.
Scalability
Wireless LAN systems can be configured in a variety of topologies to meet the needs of specific applications and installations. Configurations are easily changed and range from peer-to-peer networks suitable for a small number of users to full infrastructure networks of thousands of users that enable roaming over a broad area.