Wireless network • Usually use Radio Frequency (RF) te chnology – transmit and receive data over the air • Adv : – providing all the features of wired LAN – without the limitations of a cable • Disadv : – lower transmission speed – higher cost (when c.f. wired network)
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Wireless network Usually use Radio Frequency (RF) technology –transmit and receive data over the air Adv : –providing all the features of wired LAN –without.
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Wireless network
• Usually use Radio Frequency (RF) technology– transmit and receive data over the air
• Adv :– providing all the features of wired LAN– without the limitations of a cable
• Wireless LAN– usually used in complement with a wired LAN– becoming an alternative for wired LAN
• by means of an access point (AP)– a device that transports data between a wireless LAN
and a wired LAN– with wireless LAN Card
» wireless network interface card» wireless node
• with area of coverage
• One of the advantage of Wireless LAN– provide mobility
• suitable for – school campus– taking inventory in a warehouse– making order for a restaurant– hospitals– construction site– temporarily office – health care ; retail ; manufacturing ; warehousing
; education
Network Topology
• Network Topology = logical layout or the way in which the computers and other network devices are connected
• Each computer / device = node
• Common Topologies– Bus topology– Star topology– Ring topology
• Bus Topology– all computers and other network devices
are connect to a single central cable
– Adv :• Easy to set up• failure of one device does not affect the rest of th
e bus network
– Disadv :• failure of any point on the central bus may lead to
the failure of the whole network• only one PC can send data on a bus network
– therefore number of computer attached to the bus will affect the performance of network
» more PC, more waiting, slower the network
– 3 concepts about Bus Topology• sending the signal• signal bounce (CSMA / CD)• terminator
• Sending the signal– in form of electronic signals– sent to all computers on the network– only the computer whose address matches the address
encoded in the original signal accepts the information– all other PC reject the data
• Signal Bounce– as data is sent to the entire network– travels from one end of the cable to the other– if signal is allowed to continue uninterrupted– signal will keep bouncing back and forth– other PC cannot send signals– therefore signal must be stopped after it has a chance to
reach the proper destination address
• Terminator– to stop the signal from bouncing– a component called a terminator
» placed at each end of the cable» to absorb free signals» to clear the cable so that other PCs can send data
– both end should plug with terminator
• Star Topology– all the devices on the network
• connect to a central device (hub / switch / router)– thus forming a star
– if one device / computer fail• not affecting the others.
– If the connecting cable between an device and the central device fail / has problem
• not affecting the others
– If the central device fails– power / networking problem
• the entire network is not working
– Star topology is the most common type of network topology