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Understanding Computers Chapter 7: Computer Networks.

Dec 26, 2015

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  • Slide 1
  • Understanding Computers Chapter 7: Computer Networks
  • Slide 2
  • 2 Learning Objectives Define a network and its purpose. Describe several uses for communications technology. Understand the various topologies and architectures a computer network might use. Explain the difference between a LAN, a WAN, and a PAN, and between an intranet, an extranet, and a VPN.
  • Slide 3
  • 3 Learning Objectives Understand characteristics about data and how it travels over a network. Name specific types of wired and wireless transmission media and explain how they transmit data. Identify different protocols that can be used to connect the devices on a network. List several types of networking hardware and explain the purpose of each.
  • Slide 4
  • 4 Overview This chapter covers: Networking concepts and terminology Common networking and communications applications Technical issues related to networks, including the major types of networks, how data is transmitted over a network, and types of transmission media involved Explanation of the various ways networked devices communicate with one another Various types of hardware used in conjunction with a computer network
  • Slide 5
  • 5 What Is a Network? Network: A connected system of objects or people Computer network: A collection of computers and other hardware devices connected together so that users can share hardware, software, and data, as well as electronically communicate with each other Internet: Largest computer network in the world Types of networks Business networks Phone networks Home and multimedia networks
  • Slide 6
  • 6 Networking and Communications Applications Mobile phones (wireless phones) Cellular (cell) phones Must be within range of cell tower to function Satellite phones Used where cell service isnt available Dual-mode phones Allows users to make telephone calls on more than one network Cellular / Wi-Fi dual mode phone are most popular
  • Slide 7
  • 7 Networking and Communications Applications
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  • 8 Paging Sending short numeric or text messages to a persons pager Most often used for onsite paging applications Messaging Two-way paging Most often takes place today via a mobile phone
  • Slide 9
  • 9 Networking and Communications Applications Global positioning system (GPS): Uses satellites and a receiver to determine the exact geographic location of the receiver Commonly found in cars today Available as handheld units Used by the military, hikers, travelers, and others who need to know their precise location
  • Slide 10
  • 10 Networking and Communications Applications Monitoring systems: Monitor status or location of individuals, vehicles, assets, etc. RFID-based systems GPS-based monitoring systems Electronic medical monitors and other types of home health monitoring Digital entertainment High-definition television/radio: HDTV is replacing analog broadcasts Satellite radio: Delivers digital radio content to satellite receivers Multimedia networking and digital data distribution
  • Slide 11
  • 11 Networking and Communications Applications Videoconferencing: Use of communications technology for real-time, face-to-face meetings between individuals located in different places Technology continues to improve and mimic real- life meeting environments Telepresence videoconferenceing Online conferencing (via the Internet) Video phone calls
  • Slide 12
  • 12 Networking and Communications Applications Collaborative computing (workgroup computing): Using a computer and communications technology to work together on documents and other project Tools include Microsoft Office markup tools and collaboration software Telecommuting: Individuals work at home and communicate with their place of business and clients via communications technologies Possible because of the Internet and other communications technologies
  • Slide 13
  • 13 Networking and Communications Applications Telemedicine: Use of communications technology to provide medical information and services Remote monitoring and consultations Remote diagnosis Telesurgery
  • Slide 14
  • 14 Types of Networks Topology: How the devices in the network (called nodes) are arranged Star networks: All devices connect to a central device or hub) Bus networks: All devices connect to a central cable Ring networks: Devices connect to one another in a ring Mesh networks: Multiple connections between devices Some networks use a combination of topologies
  • Slide 15
  • 15 Network Topologies
  • Slide 16
  • 16 Types of Networks Architecture : The way networks are designed to communicate Client-server networks Client: PC or other device on the network that requests and utilizes network resources Server: Computer dedicated to processing client requests
  • Slide 17
  • 17 Types of Networks Peer-to-peer networks: All computers at the same level) Internet peer-to-peer (P2P) computing: Performed via the Internet
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  • 18 Types of Networks Local area network (LAN): Small geographical area (office, campus, etc.) Wide area network (WAN): Large geographical area (Internet) Metropolitan area network (MAN): Serves a metropolitan area Municipal Wi-Fi projects Personal area network (PAN): Connects personal devices for one individual, such as his or her portable PC, mobile phone, and portable printer
  • Slide 19
  • 19 Types of Networks Wireless sensor networks (WSNs): Contain sensors (devices that respond to a stimulus and generate an electrical signal that can be measured or interpreted) Intranet: Private network set up by an organization for use by its employees Extranet: Intranet that is at least partially accessible to authorized outsiders Virtual private network (VPN): Secure path over the Internet that provide authorized users a secure means of accessing a private network via the Internet
  • Slide 20
  • 20 Data Transmission Characteristics Analog vs. digital (waves vs. discrete) Bandwidth: The amount of data that can be sent at during a given period of time Measured in bits per second (bps) Serial vs. parallel transmission Serial = 1 bit Parallel = at least 1 byte at a time
  • Slide 21
  • 21 Data Transmission Characteristics Transmission timing Synchronous transmission (at regular, specified intervals) Asynchronous transmission (sent when ready) Isochronous transmission (sent at the same time as other, related, data)
  • Slide 22
  • 22 Data Transmission Characteristics Transmission directions Simplex transmission (one way only) Half-duplex transmission (one way at a time) Full-duplex transmission (both ways at the same time)
  • Slide 23
  • 23 Data Transmission Characteristics Type of connections Circuit-switched: Dedicated path over a network is established and all data follows that path Packet-switched: Messages are separated into small units called packets and travel along the network separately Used to send data over the Internet Broadcast: Data is sent out to all other nodes on the network Primarily used with LANs
  • Slide 24
  • 24 Type of Connections
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  • 25 Data Transmission Characteristics Wired connections: The PC is physically cabled to the network Common in schools, business, and government facilities Wireless connections: Typically use radio waves to send data through the air Rapidly becoming more popular in homes and businesses Wireless hotspots are commonly available in public locations
  • Slide 26
  • 26 Wired Network Transmission Media Twisted-pair cable Pairs of wires twisted together Used for telephone and network connections Coaxial cable Thick center wire Used for computer networks, short-run telephone transmissions, cable television delivery Fiber-optic cable Glass or fiber strands through which light can pass Used for high-speed communications
  • Slide 27
  • 27 Wired Network Transmission Media
  • Slide 28
  • 28 Wireless Network Transmission Media Use radio signals Short-range (such as Bluetooth) can connect a wireless keyboard or mouse to a PC Medium-range (such as Wi-Fi) are used for wireless LANs and to connect portable PC users to the Internet at public hotspots Longer-range (WiMAX) can be used to provide Internet access to wide geographic areas Radio frequencies are assigned by the FCC and are measured in hertz (Hz) The electromagnetic spectrum is the range of common electromagnetic radiation (energy) that travels in waves
  • Slide 29
  • 29 Wireless Network Transmission Media
  • Slide 30
  • 30 Cellular Radio Transmissions Use cellular towers within cells Calls are transferred from cell tower to cell tower as the individual moves Different transmission frequencies are used to avoid interference and allow multiple conversations to take place via a single tower at one time Widely used, but cell service not available everywhere Cell phone technology is referred to in generations Todays phones are third-generation 4G service is beginning to become available
  • Slide 31
  • 31 Cellular Radio Transmissions
  • Slide 32
  • 32 Microwave and Satellite Transmissions Microwaves: High-frequency radio signals Sent and received using microwave stations or satellites Microwave stations are ear