IS CHapter 6

electronic tranfer data from one connection to another

a communications, data exchange, resouce sharing system created by linking two or more devices

telephone and computer network converging into a single digital network

• LANs-Local area networks
• WANs-Wide area networks
• MANs-Metropolitan area networks

• 100Mbps to 10 Gbps
• client server or peer to peer model

• span several cites, states , countries
• owned by different parties
• connect to other networks

• cities and sometimes nearby cities
• community services

• NICS
• NOS
• sending receiving devices
• other connecting HW
• connection/transmission media
• protocols

• "thin client" -dumb terminal
• portable personal using devices

HW that enables computers to work over networks

runs coordinates a network

rules or governs transmissions information between two points

• TCP-establishes the connection between two computers
• IP-delivers/reassembles/disassembles packets

-collection of binary digits

when the sending computer divides the message into packets

• HW containing software
• connects networks and contains traffic between them

• HW devices that contain all other network components
• sends packets of data to all conncected devices

• more intelligence than a HUB
• can filter and forward data to a specified destination of network

convert analog signals to digital

digital signal-a signal represented by bits

• measured in bps
• bits per second

amount of data that can be transferred from one point to another in a certain time period

voice grade transmission capable of 56,000 bps

• high speed internet
• 200 kilobytes per second

loss of signal when it goes from sender to receiver

interferance caused by flouresent lights

• also called channels
• used to carry the signals between devices
• physical media- wired, guided, cable
• wirless media-radiated, unguied,broadcast

• physical path along which signals are transmitted
• twisted wire cable
• coaxial cable
• fiber optics

• advantages
• high availabitlity
• low cost
• known technology
• disadvantages
• low data
• interferance
• secuirty

• greater capacity (bandwith)
• faster
• less interferance
• not as available
• more expensive
• security

• high bandwith
• fits into small pieces
• no atenuation
• very secure
• no interferance
• more costly
• more difficult to install

• transmission through air or water
• infrared light
• high frequency radio
• microwave/satellite trasmission

uses passive or active tags in the form of chips or smart labels that can unique identifiers and relay this info to electronic readers

contains a microchop or attenea, serial number radio waves to electronic readers

one or more access points in public places to provide wireless coverage for an area

range of about 30 miles

• high frequency radio signal that is sent through the air or terristial or satellite signals
• high winds, heavy rain,EMI are also problems

• transfer signal
• orbiting the earth

24 hour well spaced satellites that orbit the earth and make it possible for people with ground receivers to pinpoint their geogrpahic location.

• Bus-open ended line with all nodes or workstations connected to the bus individually
• Ring-node connecting to the next node, travel in one direction
• Star-nodes or workstations connected to a central hub through which all messages pass

• worldwide of millions of computers
• started in 1969 as a defense project called avanced research projects agency networks

• largely text based as internet.
• using hypermedia
• embedded references used in hypermedia are called hypertext
• HTTP-the internet protocol supports the exchange of info

• identifies a web page
• includes the domain name parts
• linked to the specific IP address

unique identifier of computer or network addresses on the internet

• each domain is associated with one or more IP addresses
• 32 bit address
• Domain names are converted to IP addresses

companies that can register domain names

• email
• chatting and instant messaging
• world wide web

call digitalizes and breaks ups a voice message into data packets that travel along different routes

private network of computers using a secure tunnel

• started in early 1990s
• three step processing
• crawling
• indexing
• searching

more interactive than traditional webs

• more evolution into 3D application
• more use of the web into database

• coporate portals
• uses protocols and technologies

• secure network
• allows authorized outside users