Copyright 2011 Pearson Education Inc Publishing as Prentice
Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 1
Technology in Action Chapter 12 Behind the Scenes: Networking and Security in the Business World Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 2
Chapter Topics • • • Advantages of business networks Client/server vs. peer-to-peer networks Classifications of client/server networks Client/server network components Types of servers Network topologies Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 3
Chapter Topics (cont. ) • • • Types of transmission media Network software Network adapters Moving data in a client/server network Securing networks Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 4
Networking Advantages • Networks – Increase productivity – Enable the sharing of hardware resources – Facilitate knowledge sharing – Enable the sharing of software – Facilitate Internet connectivity – Enable enhanced communication Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 5
Client/Server Networks • Data flows efficiently • Servers respond to requests from clients • Servers perform specific tasks • Scalable • Centralized Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 6
Classifications of Client/Server Networks • LAN – Local area network – Computers linked over a small geographic area Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 7
Classifications of Client/Server Networks • WAN – Wide area network – Computers linked over large geographic areas • MAN – Metropolitan area network – Computers linked within a city or county Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 8
Classifications of Client/Server Networks • PAN – Personal area network – Wireless devices connected in close proximity to each other • Intranet – Private corporate network – Protected from the Internet by a firewall Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 9
Classifications of Client/Server Networks • Extranets – Only certain corporations or individuals can access – Useful for enabling electronic data interchange – Use virtual private networks for security Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 10
Constructing Client/Server Networks • Servers • Network topologies • Transmission media • Network operating system software • Network adapters • Network navigation devices Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 11
Servers • The number and types of servers depend on network size and workload • Dedicated servers – Perform one specific function • Authentication servers – Keep track of network logins and services available • File servers – Store and manage files Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 12
Servers • Print servers – Manage client-requested printing jobs – Create a print queue (prioritize print jobs) • Application servers – Act as a storage area for application software • Database servers – Provide clients with access to database information • E-mail servers – Process and deliver incoming and outgoing e-mail Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 13
Servers • Communications servers – Handle communications between networks, including the Internet – Often the only device on the network directly connected to the Internet • Web servers – Host a Web site available through the Internet Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 14
Network Topologies • The physical or logical layout of computers, transmission media, and other components • Types of network topologies – Bus – Ring – Star – Hybrid Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 15
Bus Topology • All nodes are connected in sequence on a single cable • Networked computers communicate with each other • One computer transmits data at a time • Becoming obsolete Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 16
Ring Topology • Nodes are laid out in a ring • A token (data packet) flows in one direction from device to device • Recent versions have data transfer rates of up to 100 Mbps Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 17
Star Topology • Most widely deployed client/server layout • Nodes connect to a central communications device (switch) • A node sends a signal to the switch, which retransmits it to the other nodes • A node accepts only signals addressed to it Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 18
Avoiding Data Collisions on an Ethernet Network Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 19
Comparing Technologies Topology Bus Advantages Disadvantages Uses a minimal amount of cabling. Breaks in the cable can disable the network. Large numbers of users will greatly decrease performance because of high volumes of data traffic. Adding or removing nodes disables the network. Failure of one computer can bring down the entire network. Problems in data transmission can sometimes be difficult to find. Easy, reliable, and inexpensive to install. Ring Star Allocates access to the network fairly. Performance remains acceptable even with large numbers of users. Failure of one computer does not affect other computers on the network. Centralized design simplifies troubleshooting and repairs. Requires more cable (and possibly higher installation costs) than a bus or ring topology. The switch is a central point of failure. If it fails, all computers connected to that switch are affected. Easy to add more computers or groups of computers as needed (high scalability). Performance remains acceptable even with large numbers of users. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 20
Transmission Media • The routes data takes to flow between devices on a network • Wired – Twisted pair – Coaxial – Fiber-optic • Wireless Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 21
Choosing a Cable • • • Maximum run length Bandwidth Bend radius Cable and installation costs Susceptibility to interference Signal transmission methods Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 22
Twisted Pair Cable • Pairs of copper wire twisted around each other • Twists make the wires less susceptible to outside interference • Two types – Shielded twisted pair (STP) – Unshielded twisted pair (UTP) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 23
Coaxial Cable • Four components – Copper core – Nonconductive insulating material – Braided metal – Plastic cover Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 24
Fiber-Optic Cable • Components include – Glass or plastic fibers – Cladding – Outer jacket • Uses light impulses to transmit data • Immune to interference Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 25
Wireless Media 802. 11 Standard • In business, wireless media are usually add-ons to a wired network • Wi-Fi 802. 11 standard – 802. 11 g – 802. 11 n Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 26
Network Operating Systems (NOS) • Provide the protocol that controls the communication among devices on the network • Many modern OSs include NOS client software • Major network operating systems – Windows Server 2008 – UNIX – Novell SUSE Linux Enterprise Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 27
Network Adapters • Devices that enable computers to communicate on a network • Network interface cards (NICs) • Three functions – Generate network transmission signals – Create data packets – Act as information gatekeepers • Ethernet compliant • Wireless NICs Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 28
Network Navigation Devices • Media access control (MAC) address – Six two-digit numbers (such as 01: 40: 87: 44: 79: A 5) – Physical address of network adapter – Internal network identification Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 29
Network Navigation Devices • Repeaters – Amplify a signal and retransmit it – Extend cable runs • Hubs – Transmit signals; have multiple ports • Receive a signal from a device • Reconstruct the signal • Transmit the signal to all ports on the hub Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 30
Network Navigation Devices • Switches and bridges – Send data on a specific route through the network – Bridges send data between collision domains • Routers – Send information between two networks Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 31
Network Security Threats • Human errors and mistakes • Malicious human activity – Current and former employees hacking or planting viruses • Natural events and disasters – Hurricanes, floods, fire Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 32
Network Security • Authentication – User ID and password used to access the network – Use of biometric devices – Use of a possessed object for access • Access privileges – Enable access to certain network systems • Physical protection measures – Restrict physical access to sensitive network equipment – Magnetic card readers – Biometric access devices Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 33
Network Security • Firewalls – Prevent access to the network by unauthorized users – Composed of software and/or hardware – Screen and validate data packets – Bastion host/proxy server Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 34
Network Firewall Layout Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 35
Chapter 12 Summary Questions • What are the advantages of a business network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 36
Chapter 12 Summary Questions • How does a client/server network differ from a peer-to-peer network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 37
Chapter 12 Summary Questions • What are the different classifications of client/server networks? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 38
Chapter 12 Summary Questions • What components are needed to construct a client/server network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 39
Chapter 12 Summary Questions • What do the various types of servers do? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 40
Chapter 12 Summary Questions • What are the various network topologies (layouts), and why is network topology important in planning a network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 41
Chapter 12 Summary Questions • What types of transmission media are used in client/server networks? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 42
Chapter 12 Summary Questions • What software needs to be running on computers attached to a client/server network, and how does this software control network communications? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 43
Chapter 12 Summary Questions • How do network adapters enable computers to participate in a client/server network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 44
Chapter 12 Summary Questions • What devices assist in moving data around a client/server network? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 45
Chapter 12 Summary Questions • What measures are employed to keep large networks secure? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 46
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 © 2011 Pearson Education, Inc. Publishing as Prentice Hall Chapter 12 47
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