tailieunhanh - Lecture Introduction to computing - Lecture 20

Even a home computer user can be part of a truly global network. A connection to the Internet makes your home computer one of the millions of nodes on the vast Internet network. You can share files, collaborate, communicate, and conference with people on the other side of the globe. This lesson examines some of the most common ways of transmitting data via networks and the Internet. | CSC 101 Introduction to Computing Lecture 20 Dr. Iftikhar Azim Niaz ianiaz@ 1 1 Last Lecture Summary I 2 Computer Communications and Network Uses of Computer Networks Internet E-mail Instant Messaging, SMS, MMS Newsgroup, RSS Tele, Audio, Video and Data Conferencing VoIP Hot Spot, CyberCafe GPS Groupware, Voice Mail, Web Services 2 Last Lecture Summary II 3 Types of Networks LAN WAN MAN Client Server Peer-to-Peer Network Topologies Bus Star Ring Mesh 3 Objectives Overview Network Media Media refers to the means used to link a network's nodes together communications channel is the transmission media on which data, instructions, or information travel in a communications system. Choice impacts Speed Security Size Communication Channel The amount of data that can travel over a communications channel sometimes is called the bandwidth Latency is the time it takes a signal to travel from one location to another on a network Transmission media are materials capable of carrying one or more signals Broadband media transmit multiple signals simultaneously Physical Transmission Media Twisted-pair cable Coaxial cable Fiber-optic cable Physical Transmission Media Twisted Pair is used for telephone systems and network cabling Coaxial cable is often used for cable television wiring Fiber optic cable is capable of carrying significantly more data at faster speeds than wire cables. Less susceptible of interference (noise) and therefore more secure Smaller size (thinner and lighter) Twisted Pair Cable Most common LAN cable Called Cat5 or 100BaseT Four pairs of copper cable twisted May be shielded from interference Speeds range from 1 Mbps to 1,000 Mbps 9 Insider information Interference is usually electrical. Magnets, solar flares or electronic devices generate interference. Coaxial Cable Similar to cable TV wire One wire runs through cable Shielded from interference Speeds up to 10 Mbps Fiber-optic Cable Data is transmitted with light pulses Glass strand instead of | CSC 101 Introduction to Computing Lecture 20 Dr. Iftikhar Azim Niaz ianiaz@ 1 1 Last Lecture Summary I 2 Computer Communications and Network Uses of Computer Networks Internet E-mail Instant Messaging, SMS, MMS Newsgroup, RSS Tele, Audio, Video and Data Conferencing VoIP Hot Spot, CyberCafe GPS Groupware, Voice Mail, Web Services 2 Last Lecture Summary II 3 Types of Networks LAN WAN MAN Client Server Peer-to-Peer Network Topologies Bus Star Ring Mesh 3 Objectives Overview Network Media Media refers to the means used to link a network's nodes together communications channel is the transmission media on which data, instructions, or information travel in a communications system. Choice impacts Speed Security Size Communication Channel The amount of data that can travel over a communications channel sometimes is called the bandwidth Latency is the time it takes a signal to travel from one location to another on a network Transmission media are materials capable of carrying