Chapter 19

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Chapter 19Networks

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What’s Inside and on the CD?

• In this chapter you’ll learn:– Basic network terminology – To identify network components – About advantages and disadvantages of networks

Practical Computer Literacy, 2nd edition Chapter 19

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What is a network?

• A Network is collection of devices with the ability to communicate with each other

• A computer network, or network, consists of two or more computers connected to allow information and devices to be shared

• Communications protocol is a set of rules for transmitting and receiving data from one network device to another

• Three popular network standards are Ethernet, Wi-Fi, and Bluetooth


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What is a network?

• A LAN (local area network) connects personal computers within a very limited geographical area

• A WAN (wide area network) covers large geographical area and consists of several smaller networks

• An Intranet is type of LAN– Like the Internet, uses Internet technology– Unlike the Internet, an intranet is maintained by a

private business or organization, and access is limited to employees

– Can be expanded into an extranet that uses public telephones and computer networks to share data


What are the components of a local area network?

• Network components include– Computers and peripheral devices used for input and

output– Specialized computers used to store and distribute

data– Network devices– Communications software

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• A network connection point is referred to as node and contains:– Computer– Peripheral device– Network communication device– Home entertainment equipment– Network-ready printer





• To connect to a LAN, a device requires network circuitry– An Ethernet adapter connects a computer to network

cabling– A Wi-Fi adapter transmits wireless signals

• Communications software formats and packages data for transport



• In an ad hoc network, network data can travel directly from one device to another

• More typically, computer networks incorporate a central device to handle communications– Hubs– Switches– Bridges– Wireless access points– Routers


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What are the roles of clients and servers on a network?

• A network server is a computer that provides services to clients

• In client/server mode, there is a hierarchical structure


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What are the roles of clients and servers on a network?

• A peer-to-peer network requires no server; treats every computer equally– Workstations can store network data and transport it

directly to others without central server– Peer-to-peer technology forms the basis for file-sharing

networks


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How does the Internet work?

• The Internet is a global communications network sometimes called “network of networks”– Uses the TCP/IP protocol– Collection of networks tied together by high-speed

links called Internet backbone

• The Internet backbone is maintained by network service providers (NSPs)– Tied together by network access points (NAPs)


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• ISP (internet service provider) is a company that offers access to Internet– ISP connects to NSP to access the Internet backbone

• Every device on the Internet has a unique IP address to identify it– IPv4 vs. IPv6– Static IP address vs. dynamic IP address

• DHCP automatically assigns IP addresses





• Many servers also have a domain name, which is easier to remember

• A domain name ends with an extension (top-level domain)– nike.com

• ICANN is the global organization that coordinates technical management of the Internet’s Domain Name System




How do I connect my computer to the Internet?

• Computers can connect to the Internet through– Telephone lines– Cable television systems– Cellular networks– Wireless hotspots– Local area networks

• The capacity of an Internet connection is sometimes referred to as bandwidth



• Fast connections are referred to as broadband– 6 Mbps or more

• Symmetrical connections transfer data upstream and downstream at the same rate

• Asymmetrical connections transfer data downstream faster than upstream



• Always-on connections remain active even when you are not online

• Types of Internet service– Cable Internet service– DSL– Dial-up Internet service

• Voiceband modem– Satellite Internet service– Wi-Fi hotspots




What are the advantages of networks?

• Advantages of using networks include:– Sharing networked hardware can reduce costs– Sharing networked software can also reduce costs– Networks can provide access to a wide range of services

of specialized peripheral devices– Sharing data on a network is easy– In business environments, networks provide a means to

monitor and control many aspects of an enterprise– Networks are convenient– Networks enable people to work together


How do networks facilitate communication and collaboration?

• Communication and collaboration tools have their own unique uses:– Message boards, online bulletin boards, and newsgroups– File Transfer Protocol– Voice over IP– Instant messaging– Text messaging– Web conferencing– Chat rooms– Social networking– Blog


How do I choose the right communications tools?

• When selecting one or more tools for a task, keep in mind the following factors:– Media– Audience

• RSS– Confidentiality– Community– Convenience– Overhead


Do networks have disadvantages?

• The primary disadvantage of networks is their vulnerability to unauthorized access

• Network administrators create network policies, supervise network maintenance, and implement security



• Fundamental network security principles include the following:– Grant access only to authorized users– Use authentication procedures– Install protective technology– Monitor the network for unusual traffic

• Wireless networks are much more susceptible than wired networks

• Loss of autonomy



• Home networks face many of the same threats as larger networks

• Network security includes the following steps:– Make sure that all network computers require user IDs and

passwords– Install antivirus software on all computers and keep it

updated– Activate the firewall software provided by your operating

system– Activate encryption on wireless networks– Install operating system updates as they become available




Documents

Chapter 19