CE 4228 DATA COMMUNICATIONS AND NETWORKING Introduction

Networks

Data Networks Communications!

Communications Communication means conveying information Usually categorized by the types of information Person-to-person Telephone Mobile phone SMS CB radio Radio Remote control Free TV Cable TV Newspaper Letter WWW

Communications – Classifications Delivery time Slow → non-electronic Newspaper, letter Fast → electronic TV, telephone The scope of this course is limited to fast delivery time, electronic communications

Communications – Classifications Medium Copper wire Telephone Waveguide or fiber optics Cable TV Free space Mobile phone Information type Voice Mobile phone Video TV Data , WWW

Communications – Classifications Information flow Simplex TV, SMS Half duplex CB radio Full duplex Telephone Full duplex exists only in physical system, but not in application level Information distribution Unicast → one-to-one Telephone Multicast → one-to-many Cable TV Broadcast → one-to-all Free TV, radio Sometimes broadcast is considered as a special case of multicast

Communications – Model

Source Generate data to be transmitted Voice, audio, video, text, digital data, etc. Transmitter Convert data into transmittable signals Can be viewed as 2 separate tasks Input transducer Translate information into electric signal Microphone, for example Transmitter Modulation, filtering, encoding, transmitting, etc.

Communications – Model Receiver Convert received signal into data Can also be viewed as 2 separate tasks Receiver Filtering, amplifying, demodulating, decoding, etc. Output transducer Revert to the original information format Loudspeaker, for example Destination Take incoming data

Communications – Model Transmission system Carry signals Twisted pair, coax, fiber, air, etc. Goal is to minimize |m' − m| In a two-way communication system, both the transmitter and the receiver are implemented within one physical unit

Communications – Networking Point-to-point communication system Link-level issues Signaling, bit rate, medium, connector types, filtering, amplification, equalization, synchronization, error control, flow control, etc. Addressing, connection establishing, switching, routing are non-issues AB

Communications – Networking Deterministic link sharing AB Multiplexing

Communications – Networking Communication network Network issues such as addressing and routing are essential

Networks Point-to-point communication usually not practical Devices are too far apart Large set of devices would need impractical number of connections Solution is communication networks Wide area networks Local area networks

Networks – WAN Wide area networks Large geographical area Crossing public rights of way Rely in part on common carrier circuits Alternative technologies Circuit switching Packet switching

Networks – WAN Circuit switching Dedicated communications path established for the duration of the conversation Telephone networks Packet switching Data sent out of sequence Small chunks of data at a time Packets Packets passed from node to node between source and destination Used for terminal to computer and computer to computer communications

Networks – LAN Local area networks Smaller scope Building or small campus Usually owned by same organization as attached devices Very high data rate

Networks – MAN Metropolitan area networks Middle ground between LAN and WAN Private or public networks High speed Large area

Networks – Wireless Wireless LAN Wi-Fi Wireless WAN Cellular systems Personal area networks System interconnection Bluetooth

Networks – Classification

Networks – Trends Traditional communication networks VoiceTelephone and cellular networks Video Cable and satellite TV networks Data Computer networks Communication revolution Digital age Driven by innovations in digital communication, signal processing, computer, IC, optics and wireless technology

Networks – Trends New generation of communication networks Voice Telephone and cellular networks Video Cable and satellite TV networks Data Computer networks Use of Internet Integrated service with differentiated QoS

CE 4228 – Outline Signals & bandwidth Transmission systems Transmission media Transmission signals Multiplexing Data link control LANs WANs Protocol architecture OSI TCP/IP

CE 4228 – Prerequisites Signals and Systems Frequency domain Communications Modulations

CE 4228 – Requirements academic.eng.au.edu/~ce4222/ Download slides “I cannot teach anybody anything, I can only make them think.” - Socrates