Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall 1

2 Technology in Action Chapter 12 Behind the Scenes: Networking and Security Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

3 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

4 Chapter Topics (cont.) Types of transmission media Network software Network adapters Moving data in a client/server network Securing networks Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

p. 619 #1 Internet risks at school#1 Internet risks at school #2 Ethical hackers#2 Ethical hackers #3 Acceptable Use Internet policies#3 Acceptable Use Internet policies Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall 5

6 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

7 Client/Server Networks Server-based network – –Clients and servers Data flows efficiently Servers respond to requests from clients Servers perform specific tasks Scalable Centralized Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

8 Classifications of Client/Server Networks LAN – –Local area network – –Computers linked over a small geographic region Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

9 Classifications of Client/Server Networks WAN – –Wide area network – –Computers linked over large geographic locations MAN – –Metropolitan area network – –Computers linked within a city or county Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

10 Classifications of Client/Server Networks PAN – –Personal area network – –Wireless devices connected in close proximity to each other Intranet – –Private corporate network – –Protected by a firewall Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

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 11 Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

12 Constructing Client/Server Networks Servers Network topologies Transmission media Network operating system software Network adapters Network navigation devices Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

13 Servers 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

14 Servers Print servers – –Manage client-requested printing jobs – –Create print queue (prioritize print jobs) Application servers – –Act as a storage area for application software Database servers – –Provide clients with access to database information servers – –Process and deliver incoming and outgoing Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

15 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

16 Network Topologies The physical or logical layout of computers, transmission media, and other components Types of network topologies – –Bus topology – –Ring topology – –Star topology – –Hybrid topology Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

17 Bus Topology All nodes are connected in sequence on a single cable Used most often in peer-to-peer networks Networked computers communicate with each other One computer transmits data at a time – –Access methods avoid data collisions – –Data is transmitted in packets Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

18 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

19 Star Topology 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

20 Avoiding Data Collisions on an Ethernet Network Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

21 Transmission Media The routes data takes to flow between devices on a network Wired – –Twisted pair – –Coaxial – –Fiber-optic Wireless Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

22 Choosing a Cable Maximum run length Bandwidth Bend radius Cable cost Cable and installation costs Susceptibility to interference Signal transmission methods Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

23 Twisted Pair Cable Pairs of copper wire twisted around each other Twists make the wires less susceptible to interference Shielded twisted pair (STP) – –Layer of foil shielding Unshielded twisted pair (UTP) – –Cat 5E: Bandwidth 200 Mbps – –Cat 6: Bandwidth 1 Gbps – –No foil layer Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

24 Coaxial Cable Four components – –Copper core – –Nonconductive insulating material – –Braided metal – –Plastic cover Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

25 Fiber-Optic Cable Components include – –Glass or plastic fibers – –Cladding – –Outer jacket Uses light impulses to transmit data Immune to interference Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

26 Wireless Media Standard Wi-Fi (short for Wireless Fidelity) – –802.11b – –802.11a – –802.11g – –Super G – –802.11n Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

27 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 Open Enterprise Server Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

28 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

29 Network Navigation Devices Media Access Control (MAC) address – –Six two-digit numbers (such as 01:40:87:44:79:A5) – –Physical address of network adapter – –Internal network identification Copyright © 2010 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

31 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

32 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

33 Network Security Authentication – –User ID and password used to access the network – –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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

34 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

35 Network Firewall Layout Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

36 Chapter 12 Summary Questions What are the advantages of a business network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

37 Chapter 12 Summary Questions How does a client/server network differ from a peer-to-peer network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

38 Chapter 12 Summary Questions What are the different classifications of client/server networks? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

39 Chapter 12 Summary Questions What components are needed to construct a client/server network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

40 Chapter 12 Summary Questions What do the various types of servers do? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

41 Chapter 12 Summary Questions What are the various network topologies (layouts), and why is network topology important in planning a network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

42 Chapter 12 Summary Questions What types of transmission media are used in client/server networks? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

43 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 © 2010 Pearson Education, Inc. Publishing as Prentice Hall

44 Chapter 12 Summary Questions How do network adapters enable computers to participate in a client/server network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

45 Chapter 12 Summary Questions What devices assist in moving data around a client/server network? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

46 Chapter 12 Summary Questions What measures are employed to keep large networks secure? Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

47 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 © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall 47 Chapter 12