CSIT127_L01 - Introduction (PDF)

Overview Every major business in the world uses a number of complex computer networks: – LANs, WANs, intranet, Internet and communications: – data communications, telecommunications, mobile communications, wireless to do business These networks and communication methods are what...

Overview Every major business in the world uses a number of complex computer networks: – LANs, WANs, intranet, Internet and communications: – data communications, telecommunications, mobile communications, wireless to do business These networks and communication methods are what we will discuss in this subject 18 Data Communications Data communications – the transfer of digital or analog data using digital or analog signals Components Data representation Direction of data flow 19 Five components of data communication system 20 Types of Information Audio Textual Textual Image Video 21 Data Codes The set of all textual characters or symbols and their corresponding binary patterns is called a data code (character set) There are two common data codes: – ASCII – Unicode 22 ASCII 23 Unicode Each character is 8/16 bits A large number of languages / character sets For example: – T equals 0000 0000 0101 0100 – r equals 0000 0000 0111 0010 – a equals 0000 0000 0110 0001 24 Computer Networks A set of devices connected by communication links A device can be a computer, printer, or any other device capable of sending and/or receiving data generated by other devices on the network – Connecting devices: router, switch, modem 26 Network topology Network topology refers to the way in which a network is laid out physically – Bus Topology – Ring Topology – Star Topology – Mesh Topology – Tree Topology – Hybrid Topology 27 The language of Computer Networks Personal area network – a network of few centimeters to several meters, between wireless devices such as smartphones, laptops, and similar devices Local area network – networks that are small in geographic size spanning a room, floor, or building Campus Area Networks - collections of local area networks that cover a campus (a Uni or a business campus) 32 The language of Computer Networks Metropolitan area network – networks that serve an area of 1 to 50km, approximately the size of a typical city Wide area network – a large network that encompasses parts of states, multiple states, countries, and the world Cloud computing – the practice of using a network of remote servers hosted on the Internet to store, manage, and process data Networks that connect resources that reside “in the cloud” 33 Networks 34 The Big Picture of Networks Networks are composed of many devices, including: – Workstations (computers, tablets, smart phones,…) – Servers – Switches – Routers, Modems 35 The Desktop Computer and the Internet Highly common throughout business and academic environments, and homes Typically a medium- to high-speed connection Computer (device) requires a NIC (network interface card) NIC connects to a hub-like device (switch) LAN connected via router to Internet How can we connect to the Internet from home? 36 The Desktop Computer and the Internet 37 Local Area Network-to-Local Area Network Found in systems that have two or more LANs and a need for them to intercommunicate A bridge-like device (such as a switch) is typically used to interconnect LANs Switch can filter out traffic 38 Local Area Network-to-Local Area Network 39 Cellular Network Constantly expanding market across the world Fifth generation services in the market Every new generation includes higher speed data transfers 40 Sensor Network Not all local area networks deal with microcomputer workstations Often found in industrial and real-world settings Assembly lines and robotic controls depend heavily on sensor-based local area networks 41 Industrial Sensor-based systems 42 Mainframe Systems Mainframe computers that support business day-to- day operations Computer terminals - used for entering data into a system, and then displaying results from the system (mainframe) 43 Satellite Networks Typically long distance wireless connections Many types of applications including digital satellite TV, meteorology, intelligence operations, mobile maritime telephony, GPS navigation systems, … 44 Cloud Networks Networks that connect resources that reside “in the cloud” Based on the concept of virtualization of services (virtualization software - hypervisor) Typically creating virtual machines – Public clouds – Private clouds – Hybrid clouds 45