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Wi-Fi or WLAN as it is usually known is fast suitable the preferred mode of connecting to the internet. Wi-Fi gets its name from a qualifications called Wireless Fidelity given to networks operating above 802.11 standards. Wi-Fi allows computers, PDAs and other devices to connect to a broadband connection in a wireless mode. The 802.11 standard defines the wireless communication operating via electromagnetic waves. Wi-Fi refers to wireless networking technology that allows computers and other devices to communicate over a wireless signal. It describes all network components that are based on one of the 802.11 standards, together with 802.11a, 802.11b, 802.11g and 802.11n. These standards were developed by the IEEE and adopted by the Wi-Fi Alliance, which trademarked the name '' Wi-Fi''.
Wi-Fi is the standard way computers connect to wireless networks. Nearly all computer now have built-in Wi-Fi cards that allows users to search for and connect to wireless routers. Many mobile devices, video game systems, and other standalone devices also include Wi-Fi capability, enabling them to connect to wireless networks as well. These devices may be able to connect to the Internet using a Wi-Fi signal. However, it is important to understand that the Wi-Fi connection only exists between the devices and the router. Most routers are connected to a DSL or Cable Modem, which provides internet access to all connected devices.
Since Wi-Fi is a wireless networking standard, any device with a ''Wi-Fi Certified'' access point, and vice-versa. However, wireless routers can be configured to only work with a specific 802.11 standard, which may prevent older equipment from communicating with the router. For example, some 802.11n routers can either be configured to only work with 802.11n devices. If this option is chosen, 802.11g devices will not able to connect to the router, even though are Wi-Fi certified.
2) Switched Ethernet
Modem Ethernet implementations frequently look nothing like their historical counterparts. Where long runs of coaxial cable provided attachments for multiple stations in legacy Ethernet, Modem Ethernet networks use twisted pair wiring or fibre optics to connect stations in a radial pattern. Where legacy Ethernet networks transmitted data at 10 Megabits per second (Mbps), modem networks can operate at 100 or even 1,000 Mbps perhaps the most striking advancement in contemporary Ethernet is the use of Switched Ethernet.
Switched networks replace the shared medium of legacy Ethernet with a dedicated segment for each station. These segments connect to a switch, which acts much like Ethernet bridge, but can connect many of these single station segments. Some Switches today can support hundreds of dedicated segments. Since the only devices on the segments are the switch and the end station, the switch picks up every transmission before it reaches another node. The switch then forwards the frame over the appropriate segment, just like a bridge, but since any segment contains only a single node, the frame only reaches the intended recipient. This allows many conversations to occur simultaneously on a switched network.
Explain and differentiate the following items
I) Wireless Adapter VS Network Card
A wireless network adapter allows a computing device to connect a wireless LAN. Wireless network adapters include a built-in radio transmitter and receiver. every adapter supports one or more of the 802.11a, 802.11b, or 802.11g Wi-Fi standards.
Wireless network adapters also exist in some different form factors. Traditional PCI wireless adapters are add-in cards intended for installation inside a desktop computer having a PCI bus. USB wireless adapters connect to the external USB port of a computer.C:\Users\Ravi\Desktop\linksys.jpg
One example of a PC Card wireless adapter, the Linksys WPC54G is shown above. Every type of wireless network adapter is small, normally less than 6 inches (0.15 m) long. Each provides equivalent wireless capability according to the Wi-Fi standard it supports. Wireless Adapter allows business people to be more productive while they travel and this also have facilitate to a network without the need to run any cables. Wireless Adapter are faster and easier to install. use wireless adapter cards also allows connectivity in areas where it would be hard to install cables
A Network Card called a Network Adapter or else Network Interface Card. The function of the network card is to set up, send ,and control data on the network. To make sure the computer and network are friendly, the card be required to be suitable for the computer's data bus architecture, and have the suitable type of socket for the cable. Each card is calculated to work with a certain kind of cable. several cards include multiple crossing point connectors (which can be configured by jumpers, DIP switches, or software).
A Network Card is the physical crossing point between the computer and cable. it converts the data sent by the computer into a form which can be used by the network cable, transfers that data to an extra computer and controls the dataflow among the computer and cable.
II) Wireless Router VS Switch
Wireless Router is an Internet router, Wi-Fi access point and Ethernet switch (base station) network device that, along with a modem, comprises the entire network communications in a office or house. By combining the most important network components in one box, wireless routers present a suitable way to attach a small number of wired and several number of wireless devices mutually for file sharing to the Internet.
The Wireless router keeps local interchange within the network and onward Internet interchange to the modem of the cable. It receives responses from the Internet and attempts to prevent unrequested interchange from coming in. The access point is the Wi-Fi transmitter and receiver.
A Switch is a hardware devices that joins various computers together within one Local Area Network (LAN). network switches operate at layer two (Data Link Layer) of the OSI model. Switches appear nearly equal to (network hubs) but a switch generally contains additional intelligence than a hub.by delivering messages only to the connected device deliberate, a network switch conserves network bandwidth and offer usually improved show than a hub.
Different between Router and Switch
Data Link Layer
(Layer 3 Devices)
(Layer 2 Devices)
1-10 Mbps (Wireless)
10/100 Mbps, 1 Gbps
100 Mbps (Wired)
In Full Duplex Switch
Switch is multi port bridge
Frame (L2 Switch) Frame &
Packet (L3 Switch)
In Router, every port has it
Switch has one broadcast
own Broadcast Domain
take more time
Network Address translation
Linksys WRT54GL Juniper
Alcatel 's Omni Switch 9000
MX & EX Series Cisco 3900,
Cisco Catalyst Switch 4500 and
6500 (10 Gbps)
1) Ethernet Topology
there are 3 most important Ethernet Topologies :-
I) Star Topology
II) Tree Topology
III) Bus Topology
I) Star Topology
The Star Topology is the individual nodes are linked to a Switch. the switch straight to every controller, or other switches. The nodes can communicate with each other. In addition a switch will go down, however through linking few switches mutually, the various. The Star Topology below will make it clear.C:\Users\Ravi\Desktop\Star.jpg
Easy to configure
Natively present data, remote management and monitoring of devices
Easy to make repairs and detect problem
communication from switch to every node
if one switch fail, the nodes cannot communicate
requires extra cable than bus topology
II) Tree Topology
The Tree Topology integrates the kind of Star and Bus Topology. In Tree Topology, the amount of the star networks are connected by using Bus. this main cable shown like a main stem of a tree and other star networks as the branches. that is also called Expanded Star Topology. the Ethernet protocol is normally used in this type of topology. the Tree Topology diagram below will make it clear. C:\Users\Ravi\Desktop\tree.jpg
Communication from Switch to each Node
The Node also can connect to more than one Switch
Provides interchange communication pathway if a switch go down
Easy to detect faults and make repairs
If stamina breaks entire section goes down
Not easy to configure
Length of every limited by the type of cable used
III) Bus Topology
The original Ethernet communication standard released in 1983 was controlled in a bus topology and a multi-drop transmission medium, all node on the network. At the time, only one devices can allows to transmit. A circulated access protocol determines which station is to transmit. Data frames have source and destination addresses, where every station monitors the bus and copies frames addressed to itself. the Bus Topology diagram below will make it clear.
Easy to apply and extend
Compatible for temporary networks that must be set up in a speed
Easy to Configure
Hard to determine the problem
send data one bit at one time only
have limited to compared a few components to Ethernet
2) WLAN Topology
I) Basic Service Sets (BSSs)
II) Extended Service Sets (ESSs)
III) Independent Basic Service Sets (IBSSs)
I) Basic Services Sets (BSSs)
In 802.11 BSS is a group stations communicate. Access point (AP) is requires BSS has a specialized station. The access point is the central point to communicate with all the stations in BSS. The customer stations do not communicate straight other customer stations although the customer must communicate with the access point, then only the access point forwards the frames to the destination stations. Other than that, the access point capacity be able to with an uplink port to connect BSS. the BSS diagram below will make it clear.
II) Extended Service Sets (ESSs)
In the planet of 802.11, BSS the uplink crossing point connect to the distribution system (DS). The set of BSSs inter connected via the distribution system (DS) is recognized as the Extended Service Sets (ESS). the practical implementation diagram below will make it clear.
Distribution System (DS) does not have to a wired connection. 802.11 requirement leaves are the possible for this link to be wireless.
III) Independent Basic Service Set (IBSSs)
Independent Basic Service Set (IBSSs) is consists of 802.11 group that is can communicate directly with one another and IBSS is ad-hoc network because that is a simple peer to peer WLAN. the Independent Basic Service Sets (IBSS) diagram below shown network interface cards can form IBSS to communicate straight with one another. C:\Users\Ravi\Desktop\IBSS.jpg
Explain the following IEEE Standards :-
A family unit of IEEE standards that enlarge the ordinary wired Ethernet local network standard into the wireless domain. The 802.11 standards are usually known as "Wi-Fi" because the Wi-Fi Alliance provides certification for 802.11 products. There have been four major 802.11 standards selected with letter suffixes (a, b, g and n); the most recent and fastest being 802.11n (the slowest is 802.11b, and the two medium speed are 802.11a and 802.11g). For additional about Wi-Fi networks, see Wireless LAN and Wi-Fi. Following are the 802.11 specifications, from slowest to fastest.
11b (1999) - Slow Speed
11a (1999) - Medium Speed
11g (2003) - Medium Speed
11n (2009) - highest Speed
11ac (2012) - Faster Yet
802.3 is a standard requirement for Ethernet, a technique of physical communication in a local area network (LAN), which is maintain by the Institute of Electrical and Electronics Engineers (IEEE). In general, 802.3 specifies the physical media and the working features of Ethernet. The original Ethernet supports a data rate of 10 megabits per second (Mbps) and specifies these possible physical media
10BASE-2 (Thin wire coaxial cable with a maximum segment length of 185 meters)
10BASE-5 (Thick wire coaxial cable with a maximum segment length of 500 meters)
10BASE-F (Optical Fibre cable)
10BASE-T (ordinary telephone twisted pair wire)
10BASE-36 (broadband multi-channel coaxial cable with a maximum segment length of 3,600 meters)
CSMA/CD : Caring sensing, deferral as in CSMA
colliding transmissions aborted, reducing channel wastage
collisions detected with him short time
persistent or non-persistent retransmission
easy in wired LANs. measure signal strengths, compare transmitted, received signals
difficult in wireless LANs. receiver shut off while transmitting