Understanding Computers Ch.8 Chapter 8 Computer Networks Understanding Computers Ch.8

Understanding Computers Ch.8 Learning Objectives Describe several uses for communications technology. 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 messages from one device to another. Understanding Computers Ch.8

Learning Objectives, Cont’d. Explain the difference between local area, wide area, and other types of networks. List several types of networking hardware and explain the purpose of each. Identify the different protocols that can be used to connect the devices on a network. Discuss some security issues involved with computer network usage and some security precautions that can be taken. Understanding Computers Ch.8

Understanding Computers Ch.8 Overview This chapter covers: Common networking and communications applications The concepts and terminology involved with computer networks Common types of networks and the hardware and software involved in a computer network Various communications protocols that can be used Network security issues Understanding Computers Ch.8

Networking and Communications Applications Wireless phones Cellular phones Satellite phones Paging and messaging Global positioning systems (GPSs) Satellite radio Understanding Computers Ch.8

Networking and Communications Applications, Cont’d. Online conferencing (online meetings) Videoconferencing Web conferencing Collaborative computing Telecommuting Telemedicine Understanding Computers Ch.8

What Is a Network and How Does it Transmit Data? Computer network—a collection of computers and other hardware connected together to share data, hardware, software, programs, and facilitate electronic communication. Understanding Computers Ch.8

Data Transmission Characteristics Analog (continuous wave) vs. digital (discreet 0s and 1s). Bandwidth and speed (higher bandwidth allows more data to travel at the same time). Serial vs. parallel transmission. Understanding Computers Ch.8

Data Transmission Characteristics, Cont’d. Transmission directions Simplex transmission (one way only). Half-duplex transmission (one way at a time). Full-duplex transmission (both ways at the same time). Understanding Computers Ch.8

Data Transmission Characteristics, Cont’d. Transmission timing Synchronous transmission Asynchronous transmission Isochronous transmission Understanding Computers Ch.8

Wired vs. Wireless Connections With a wired network connection, the PC is physically cabled to the network. Common in schools, business, and government facilities. Wireless network connections allow great freedom regarding where users can use their PCs. Increasingly common in homes, businesses, and wireless public hot spots (e.g. Starbucks). Understanding Computers Ch.8

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 cable TV and network connections. Fiber-optic cable Glass or fiber strands through which light can pass. Used for high-speed communications. Understanding Computers Ch.8

Understanding Computers Ch.8

Wireless Network Transmission Media Broadcast radio transmissions (FM and AM radio broadcasts, short-range networking and wireless devices). Microwave and satellite transmissions. Microwave stations Communications satellites Cellular radio transmissions. Understanding Computers Ch.8

Understanding Computers Ch.8

Understanding Computers Ch.8 Network Topologies Star Bus Ring Combination Understanding Computers Ch.8

Network Architectures Client-server networks Client—makes requests of servers. Server—fulfills client requests (for files, programs, Web pages, etc.). Peer-to-peer networks (all computers at the same level) Often takes place via the Internet. Understanding Computers Ch.8

LANs, WANs, and Other Types of Networks Local area networks (LANs) Wide area networks (WANs) Metropolitan area networks (MANs) Personal area networks (PANs) Understanding Computers Ch.8

LANs, WANs, and Other Types of Networks, Cont’d. Intranets and extranets Virtual private networks (VPNs) Storage area networks (SANs) Understanding Computers Ch.8

Understanding Computers Ch.8 Networking Hardware Network adapters, also called network interface cards (NICs). Needed to connect PC to network. Come in a variety of formats (internal or external, wireless or wired, PC card, USB, etc.). Understanding Computers Ch.8

Understanding Computers Ch.8

Networking Hardware, Cont’d. Modems (used to connect PC to the Internet) Conventional dial-up ISDN DSL Cable Satellite Understanding Computers Ch.8

Networking Hardware, Cont’d. Hubs, switches, and routers Wireless access points Gateways and bridges Repeaters Multiplexers and concentrators Understanding Computers Ch.8

Understanding Computers Ch.8

Communications Protocols Communications protocol—an agreed-upon standard for transmitting data between two devices on a network. Common wired protocols are Ethernet, Token Ring, and TCP/IP. Common wireless protocols are 802.11 (Wi-Fi), Bluetooth, and WAP. Understanding Computers Ch.8

Understanding Computers Ch.8 Ethernet Typically used with wired LANs. Utilizes a set of procedures (CSMA/CD) to send data and make sure it arrives. Traditional (10Base-T) Ethernet networks run at 10 Mbps; newer 100 Mbps and 1 Gbps versions are now available. Understanding Computers Ch.8

Understanding Computers Ch.8 Token Ring Usually used with a ring network topology and utilizes a token to send and retrieve data. Understanding Computers Ch.8

Understanding Computers Ch.8 TCP/IP The protocol used with the Internet also increasingly being used with LANs. Sends data in packets. Understanding Computers Ch.8

Understanding Computers Ch.8 802.11 (Wi-Fi) and Bluetooth 802.11 (Wi-Fi for wireless fidelity)—a family of wireless networking standards. 802.11b is the original standard (11 Mbps). 802.11g is faster (54 Mbps) and expected to eventually replace 802.11b. Newer versions are in development. Bluetooth is a standard for low-cost, short-range, wireless connections between Bluetooth-enabled devices. Understanding Computers Ch.8

Other Networking Protocols Wireless Application Protocol (WAP)—for Web content delivered to smart phones and other mobile devices. IrDA—used for short range infrared data transfers. Phoneline (Home PNA) Powerline Ultra Wideband (UWB)—for home multimedia delivery. Understanding Computers Ch.8

Network Security Issues Unauthorized access and unauthorized use. Hacking War driving Protecting against unauthorized access and use. Possessed knowledge systems (e.g. passwords). Possessed object systems (e.g. cards or badges). Biometric systems (e.g fingerprint scanners or face readers). Firewalls and other protective software. Understanding Computers Ch.8

Network Security Issues, Cont’d. Computer sabotage Computer viruses and other types of malware (e.g. computer worms and Trojan horses). Denial of service (DoS) attacks. Malicious spamming. Data or program alteration. Understanding Computers Ch.8

Understanding Computers Ch.8

Network Security Issues, Cont’d. Protecting against computer sabotage. Use up-to-date antivirus and firewall software. Limit sharing disks and other removable storage media. Only download programs from reputable Web sites. Only open e-mail attachments that aren’t executable and are from people you know. Regularly download and install the latest security patches available for your e-mail program and browser. Understanding Computers Ch.8

Understanding Computers Ch.8 Summary Networking and communications applications What is a network and how does it transmit data? Types of networks Networking hardware Communications protocols Network security issues Understanding Computers Ch.8