Computers Are Your Future Tenth Edition Chapter 8: Networks: Communicating & Sharing Resources Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall1

2 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 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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall4

What You Will Learn Contrast circuit-switching and packet- switching networks and explain their respective strengths and weaknesses. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall5

Networks: Communicating & Sharing Resources Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall6

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) Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall7

Network Fundamentals Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall8

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 media Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall9

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall10

Network Fundamentals Communication devices include: Computers Modems Routers Switches Network interface cards (NICs) Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall11

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall12

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 network Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall13

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 Hall14

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall15

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 users Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall16

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall17

Local Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall18

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall19

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall20

Local Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall21

Local Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall22

Local Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall23

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall24

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall25

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall26

Local Area Networks Popular LAN Protocols Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall27

Local Area Networks Popular Wireless Networking Standards Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall28

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall29

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall30

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall31

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. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall32

Wide Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall33

Wide Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall34

Wide Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall35

Wide Area Networks Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall36

Wide Area Networks Circuit switching Data sent over a physical circuit Best when avoiding delivery delay is vital High-speed electronic switches make connections Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall37

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 Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall38

Wide Area Networks WAN applications include: Conferencing Document exchange Remote database access Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall39

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 Hall40

What You’ve Learned 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.

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 Hall42

What You’ve Learned The technologies on which WAN protocols are based use either circuit switching (PSTN) or packet switching (the Internet). Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall43