computers are your future tenth edition chapter 8: networks: communicating & sharing resources...

Computers Are Your Future

Tenth Edition

Chapter 8: Networks: Communicating & Sharing

Resources

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1

22

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic,

mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America.

Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice HallPublishing as Prentice Hall

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.

3Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

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.


What You Will Learn

Contrast circuit-switching and packet-switching networks and explain their respective strengths and weaknesses.


Networks: Communicating & Sharing Resources


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)



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

mediaCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9


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


Network Fundamentals Communication

devices include: Computers Modems Routers Switches Network interface

cards (NICs)



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.



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


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


Local Area Networks


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


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.


Local Area Networks


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.


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.


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.


Local Area Networks

Popular LAN Protocols


Local Area Networks

Popular Wireless Networking Standards


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


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.


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


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.


Wide Area Networks


Wide Area Networks

Circuit switching Data sent over a physical circuit Best when avoiding delivery delay is

vital High-speed electronic switches make

connections


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


Wide Area Networks

WAN applications include: E-mail Conferencing Document exchange Remote database access


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


41Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

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.


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


The technologies on which WAN protocols are based use either circuit switching (PSTN) or packet switching (the Internet).


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