Computers Are Your Future
Tenth Edition
Chapter 8: Networks: Communicating & Sharing
Resources
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What You Will Learn
Understand basic networking concepts.
Discuss the advantages and disadvantages of networks.
Distinguish between peer-to-peer and client/server local area networks (LANs).
Define topology and understand how the three LAN topologies differ.
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What You Will Learn Explain the importance of network
protocols. Name the most widely used LAN
protocol and its versions. Identify the special components of
a wide area network (WAN) that differentiate it from a LAN.
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What You Will Learn
Contrast circuit-switching and packet-switching networks and explain their respective strengths and weaknesses.
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Networks: Communicating & Sharing Resources
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Network Fundamentals
A network links multiple computer systems to enable them to share data and resources.
The two main categories of computer networks are: Local area network (LAN) Wide area network (WAN)
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Network Fundamentals
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Network Fundamentals
A local area network (LAN) May be wireless or connected through
cables Covers a limited geographic area
A wide area network (WAN) Links computer systems that can be
thousands of miles apart May require long-distance transmission
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Network Fundamentals
Communication devices Required to convert data into signals
that can be transferred over wired or wireless media
Convert data to and from analog signals to digital signals
Assist in digital communication Enhance signal strength Enable effective data transfer
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Network Fundamentals Communication
devices include: Computers Modems Routers Switches Network interface
cards (NICs)
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Network Fundamentals
A computer is called a client or a node when it is part of a network.
A node can be any computer or peripheral device on a network.
A computer needs a network interface card (NIC) to connect to a network.
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Network Fundamentals
Routers Connect two or more networks Determine the best route to transmit
data Switches
Provide a function similar to that of a router
Move data within one networkCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 13
Network Fundamentals The majority of networks have a file
server, a special computer that holds the network’s programs, data files, and network operating system (NOS).
Network operating systems provide file directories for file and resource location, computerized software update distribution, and Internet services support.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 14
Advantages & Disadvantages of Networking
Advantages of networking Hardware cost
reduction Sharing of
information, data, and applications
Data management centralization
Linking of people
Disadvantages of networking Loss of autonomy Lack of privacy Security threats Productivity loss
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Local Area Networks
Local area networks can be classified as either peer-to-peer or client/server.
Peer-to-peer (P2P) networks: Share files without a file server Are easy to set up Are normally used for home or small
offices Slow down if there are too many usersCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 16
Local Area Networks
Client/server networks: Made up of one or more file servers
and clients Client requests sent to server Wired or wireless connections Do not slow down with heavy usage
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Local Area Networks
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Local Area Networks
A network topology The physical design of a LAN Responsible for resolving the problem
of contention Conflict that occurs when two or more
computers on the network attempt to transmit at the same time
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Local Area Networks
Three types of LAN topologies are: Bus topology, which is used primarily
in comparatively small environments such as a home or small office.
Star topology, which works best in environments such as office buildings, computer labs, and WANs.
Ring topology, which is best used within a division of a company or on one floor of a multiple floor building.
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Local Area Networks
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Local Area Networks
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Local Area Networks
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Local Area Networks
Protocols are the standards used by networks to permit communication between network-connected devices.
A network’s protocol suite contains the protocols of the network and specifies its network architecture, or how the network works.
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Local Area Networks
Because of the complexity of networks, network layers are used to divide the network architecture.
A network layer can operate and be treated distinctly from the other layers in the network architecture.
The vertical arrangement of network layers is called a protocol stack.
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Local Area Networks
Ethernet is the most-used local area network protocol.
The two versions of Ethernet, which use twisted-pair wiring and switches, are: 10Base-T (10 Mbps) 100Base-T (100 Mbps)
Wi-Fi uses radio waves to provide a wireless LAN standard.
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Local Area Networks
Popular LAN Protocols
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Local Area Networks
Popular Wireless Networking Standards
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Wide Area Networks
Wide area networks are used to link computers spread over large geographic areas.
The two distinguishing components of a WAN, not part of a local area network, are: A point of presence (POP) A backbone
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Wide Area Networks
A point of presence (POP) is the connection point of a WAN used by individuals to obtain access to the network.
Backbones are transmission lines that have the ability to handle the massive traffic associated with a WAN.
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Wide Area Networks
Protocols Transmission Control Protocol (TCP)
Defines how Internet-connected computers can exchange, control, and confirm messages
Internet Protocol (IP) Provides a distinct identification to any computer
connected to the Internet – the IP address TCP/IP
Together, they define how the Internet works
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Wide Area Networks
The technologies on which WAN protocols are based include: Circuit switching, used by the public
switched telephone network (PSTN), sends data is sent over a physical end-to-end circuit between the sending and receiving computers.
Packet switching, used by the Internet, divide and send outgoing messages as packets, which are reassembled upon receipt.
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Wide Area Networks
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Wide Area Networks
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Wide Area Networks
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Wide Area Networks
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Wide Area Networks
Circuit switching Data sent over a physical circuit Best when avoiding delivery delay is
vital High-speed electronic switches make
connections
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Wide Area Networks
Packet switching Message divided into numbered packets Sent to router to distribute Packets sent through multiple paths Message reconstituted
Packet switching vs. circuit switching More efficient Less expensive More reliable
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Wide Area Networks
WAN applications include: E-mail Conferencing Document exchange Remote database access
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What You’ve Learned
Computer networks of two or more linked computers share resources and exchange data.
The two main types of networks are local area networks (LANs) and wide area networks (WANs).
There are advantages and disadvantages to using a computer network.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40
What You’ve Learned
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The two main categories of local area networks are peer-to-peer and client/server.
The topologies of a LAN include the bus topology, the ring topology, and the star topology.
The manner in which network devices communicate is defined by protocols.
What You’ve Learned
The Ethernet is the most popular LAN protocol.
Distinguishing components of a WAN, when compared with a LAN, are its point of presence (POP) and backbones.
WAN connections may be made through analog telephone calls or digital hookups.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 42
What You’ve Learned
The technologies on which WAN protocols are based use either circuit switching (PSTN) or packet switching (the Internet).
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