18-07-2012, 12:18 PM
wifi
wifi report.docx (Size: 190.61 KB / Downloads: 34)
ABSTRACT
Technology is no longer judged by its technical brilliance, but by the return on investment (both tangible and intangible). This in turn, is dictated by the killer application for that technology. Wireless Networks fit into this because the technology has been around long enough and can provide enough benefits to be seriously considered for deployment.
At the enterprise, it provides communication support for mobile computing. It overcomes and, in fact, annihilates the physical limitation of wired networks in terms of adaptability to a variation in demand. Network connectivity in a company’s meeting room is a classic example. The number of users using that room would vary for different meetings.
Mobility is another feature by wireless. Mobile users can be truly mobile, in that hey don’t need to be bound to their seats when connecting to the network. Mobility, however is not only associated with users, it’s also associated with the infrastructure itself. This leads to other provision of wireless, that of scalability. It really helps in extending your network. It also becomes important if an enterprise has a rented office and needs to shift to a new place. Wi-Fi, or wireless fidelity, is freedom: it allows you to connect to the internet from your couch at home, a bed in a hotel room, or a conference room at work without wires. It is a wireless technology like cell phones, Wi-Fi enabled computers send and receive data indoors and outdoors; anywhere within the range of the base station. And the best thing of all, Wi-Fi is fast. In fact, it’s several times faster than the fastest cable modem connection.
1. IEEE 802.11b Wireless Networking Overview
Approval of the IEEE 802.11 standard for wireless local area networking (WLAN) and rapid progress made toward higher data rates have put the promise of truly mobile computing within reach. While wired LANs have been a mainstream technology for at least fifteen years, WLANs are uncharted territory for most networking professionals.
In September of 1999, the Institute of Electrical and Electronic Engineers (IEEE) ratified the specification for IEEE 802.11b, also known as Wi-Fi. IEEE 802.11b defines the physical layer and media access control (MAC) sub layer for communications across a shared, wireless local area network (WLAN).
At the physical layer, IEEE 802.11b operates at the radio frequency of 2.45 gigahertz (GHz) with a maximum bit rate of 11 Mbps. It uses the direct sequence spread spectrum (DSSS) transmission technique. At the MAC sub layer of the Data Link layer, 802.11b uses the carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol.
A wireless station with a frame to transmit first listens on the wireless medium to determine if another station is currently transmitting (this is the carrier sense portion of CSMA/CA). If the medium is being used, the wireless station calculates a random back off delay. Only after the random back off delay elapses can the wireless station again listen for a transmitting station. By instituting a random back off delay, multiple stations that are waiting to transmit do not end up trying to transmit at the same time (this is the collision avoidance portion of CSMA/CA). Collisions can occur and, unlike with Ethernet, they might not be detected by the transmitting nodes. Therefore, 802.11b uses a Request to Send (RTS)/Clear to Send (CTS) protocol with an Acknowledgment (ACK) signal to ensure that a frame is successfully transmitted and received.
Wireless Network Made Up Of :-
There are two kinds of wireless networks:
a. An ad-hoc, or peer-to-peer wireless network consists of a number of computers each equipped with a wireless networking interface card. Each computer can communicate directly with all of the other wireless enabled computers. They can share files and printers this way, but may not be able to access wired LAN resources, unless one of the computers acts as a bridge to the wired LAN using special software. (This is called "bridging")
Ad-Hoc or Peer-to Peer Networking.
Each computer with a wireless interface can communicate directly with all of the others.
b. A wireless network can also use an access point, or base station. In this type of network the access point acts like a hub, providing connectivity for the wireless computers. It can connect (or "bridge") the wireless LAN to a wired LAN, allowing wireless computer access to LAN resources, such as file servers or existing Internet Connectivity.
There are two types of access points:
i. Dedicated hardware access points (HAP) such as Lucent's WaveLAN, Apple's Airport Base Station or WebGear's AviatorPRO. (See Figure 2). Hardware access points offer comprehensive support of most wireless features, but check your requirements carefully.
ii. Software Access Points which run on a computer equipped with a wireless network interface card as used in an ad-hoc or peer-to-peer wireless network. (See Figure 1) The Vicomsoft InterGate suites are software routers that can be used as a basic Software Access Point, and include features not commonly found in hardware solutions, such as Direct PPPoE support and extensive configuration flexibility, but may not offer the full range of wireless features defined in the 802.11 standard.
With appropriate networking software support, users on the wireless LAN can share files and printers located on the wired LAN and vice versa. Vicomsoft's solutions support file sharing using TCP/IP.
wifi report.docx (Size: 190.61 KB / Downloads: 34)
ABSTRACT
Technology is no longer judged by its technical brilliance, but by the return on investment (both tangible and intangible). This in turn, is dictated by the killer application for that technology. Wireless Networks fit into this because the technology has been around long enough and can provide enough benefits to be seriously considered for deployment.
At the enterprise, it provides communication support for mobile computing. It overcomes and, in fact, annihilates the physical limitation of wired networks in terms of adaptability to a variation in demand. Network connectivity in a company’s meeting room is a classic example. The number of users using that room would vary for different meetings.
Mobility is another feature by wireless. Mobile users can be truly mobile, in that hey don’t need to be bound to their seats when connecting to the network. Mobility, however is not only associated with users, it’s also associated with the infrastructure itself. This leads to other provision of wireless, that of scalability. It really helps in extending your network. It also becomes important if an enterprise has a rented office and needs to shift to a new place. Wi-Fi, or wireless fidelity, is freedom: it allows you to connect to the internet from your couch at home, a bed in a hotel room, or a conference room at work without wires. It is a wireless technology like cell phones, Wi-Fi enabled computers send and receive data indoors and outdoors; anywhere within the range of the base station. And the best thing of all, Wi-Fi is fast. In fact, it’s several times faster than the fastest cable modem connection.
1. IEEE 802.11b Wireless Networking Overview
Approval of the IEEE 802.11 standard for wireless local area networking (WLAN) and rapid progress made toward higher data rates have put the promise of truly mobile computing within reach. While wired LANs have been a mainstream technology for at least fifteen years, WLANs are uncharted territory for most networking professionals.
In September of 1999, the Institute of Electrical and Electronic Engineers (IEEE) ratified the specification for IEEE 802.11b, also known as Wi-Fi. IEEE 802.11b defines the physical layer and media access control (MAC) sub layer for communications across a shared, wireless local area network (WLAN).
At the physical layer, IEEE 802.11b operates at the radio frequency of 2.45 gigahertz (GHz) with a maximum bit rate of 11 Mbps. It uses the direct sequence spread spectrum (DSSS) transmission technique. At the MAC sub layer of the Data Link layer, 802.11b uses the carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol.
A wireless station with a frame to transmit first listens on the wireless medium to determine if another station is currently transmitting (this is the carrier sense portion of CSMA/CA). If the medium is being used, the wireless station calculates a random back off delay. Only after the random back off delay elapses can the wireless station again listen for a transmitting station. By instituting a random back off delay, multiple stations that are waiting to transmit do not end up trying to transmit at the same time (this is the collision avoidance portion of CSMA/CA). Collisions can occur and, unlike with Ethernet, they might not be detected by the transmitting nodes. Therefore, 802.11b uses a Request to Send (RTS)/Clear to Send (CTS) protocol with an Acknowledgment (ACK) signal to ensure that a frame is successfully transmitted and received.
Wireless Network Made Up Of :-
There are two kinds of wireless networks:
a. An ad-hoc, or peer-to-peer wireless network consists of a number of computers each equipped with a wireless networking interface card. Each computer can communicate directly with all of the other wireless enabled computers. They can share files and printers this way, but may not be able to access wired LAN resources, unless one of the computers acts as a bridge to the wired LAN using special software. (This is called "bridging")
Ad-Hoc or Peer-to Peer Networking.
Each computer with a wireless interface can communicate directly with all of the others.
b. A wireless network can also use an access point, or base station. In this type of network the access point acts like a hub, providing connectivity for the wireless computers. It can connect (or "bridge") the wireless LAN to a wired LAN, allowing wireless computer access to LAN resources, such as file servers or existing Internet Connectivity.
There are two types of access points:
i. Dedicated hardware access points (HAP) such as Lucent's WaveLAN, Apple's Airport Base Station or WebGear's AviatorPRO. (See Figure 2). Hardware access points offer comprehensive support of most wireless features, but check your requirements carefully.
ii. Software Access Points which run on a computer equipped with a wireless network interface card as used in an ad-hoc or peer-to-peer wireless network. (See Figure 1) The Vicomsoft InterGate suites are software routers that can be used as a basic Software Access Point, and include features not commonly found in hardware solutions, such as Direct PPPoE support and extensive configuration flexibility, but may not offer the full range of wireless features defined in the 802.11 standard.
With appropriate networking software support, users on the wireless LAN can share files and printers located on the wired LAN and vice versa. Vicomsoft's solutions support file sharing using TCP/IP.