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C021TV-I4-S3. ICN : 4. Computer and networks architecture. 1. Elementary components of a computer 2. Execution principles of a computer program 3. Data transmission principle 4. Network structuring. Communicate on a wire. How does information get transferred ?
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ICN : 4. Computer and networks architecture 1.Elementary components of a computer 2.Executionprinciples of a computer program 3.Data transmission principle 4.Network structuring
Communicate on a wire • How does information gettransferred? • First, let’sconsider a wired communication • A printer or a phone with a USB cable for example Data istransferred bit after bit, byte after byte (serial) Transmitter’s memory 0111001101… Receiver’s memory 011 0 1 1 0 0 1
Transmitting bits on a wire • Each bit isassociatedwith an electricalpotential value • 0 or 5 volts for example • That voltage isapplied on the transmitter’sside • And itismeasured on the receiver’sside • How can we know to how many bits of 1 corresponds a millisecondwith 5 volts? • Preliminary agreement on the transmission’sfrequency
Types of wiredconnectors • Needs for great distances and high frequency • Energy loss (Joule heating) • Variousconnector types • Coaxial cable (the « cable », the classical TV antenna) • Twisted pair (RJ45, USB, etc.) • Optical fiber • According to length, frequency, output and interfrencytolerancethatisneeded
Wireless communication • Suppresswireconstraints • Deployment, mobility, … • Use electromagneticwaves • Hertziantelevision, radio, wifi, mobile phones, … • Adressingproblem • To whomis the messasgeintended? Enables direct emissiontowardsmanyreceivers
Someorders of magnitude • Transferring a PDF document (100ko) • Between 0,01 and 0,1 second towards a USB printer (or in wifi, or in 4G) • 10 µs on an opticalfiber • Tranferring a Full HD movie (1Go) • 0,1 second swith an opticalfiber, 5 minutes with ADSL • Full HD video streaming (1Mo/s) • Difficultwith Wifi and 3G if receptionisbad
Pictures • p. 5 : Antenna on town 01.jpg CC-BY-SA-4.0 selfvia Wikimedia Common https://creativecommons.org/licenses/by-sa/4.0/deed.en