FIT1047 Lecture Notes - Lecture 9: Data Link Layer, Network Interface Controller, Pci Express
Document Summary
Network interface card > (switch) etwork cable > server. Provides physical connection to the network (socket or antenna) Implements protocols (error detection, construction of frames, modulation or encoding etc) Or connected via usb, pci express etc. Utp (unshielded twisted pair, most common type for lan) Optical fibre (not yet common in lans) Discrete values (eg. 0 and 1, or characters in alphabets) Discrete step from one symbol to the next. Sound (pressure wave in air), light and radio (electromagnetic waves) Analog signal for analog data eg. analog fm radio. Digital signals for digital data eg. old ethernet, usb, the bus in a computer. Analog signals for digital data eg. modems, adsl, ethernet, wifi, 4g. Digital signals are typically transmitted through copper cables. A digital signal encodes 0s and 1s into different voltage level on the cable. None return to zero (nrz) _|-|___|-|_ 1 0 0 1 1 1 0 1.