2009 PrenticeHall Inc 1 Technology in Action Chapter

© 2009 Prentice-Hall, Inc. 1

Technology in Action Chapter 12 Behind the Scenes: Networking and Security © 2009 Prentice-Hall, Inc. 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 © 2009 Prentice-Hall, Inc. 3

Chapter Topics (cont. ) • • • Types of transmission media Network software Network adapters Moving data in a client/server network Securing networks © 2009 Prentice-Hall, Inc. 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 © 2009 Prentice-Hall, Inc. 5

Client/Server Networks • Server-based network – Clients and servers • Data flows efficiently • Servers respond to requests from clients • Servers perform specific tasks • Scalable • Centralized © 2009 Prentice-Hall, Inc. 6

Classifications of Client/Server Networks • LAN – Local area network – Computers linked over a small geographic region © 2009 Prentice-Hall, Inc. 7

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 © 2009 Prentice-Hall, Inc. 8

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 © 2009 Prentice-Hall, Inc. 9

Constructing Client/Server Networks • Servers • Network topologies • Transmission media • Network operating system software • Network adapters • Network navigation devices © 2009 Prentice-Hall, Inc. 10

Servers • Number and type 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 © 2009 Prentice-Hall, Inc. 11

Servers • Print servers – Manage client-requested printing jobs – Create print queue (prioritize print jobs) • Applications 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 © 2009 Prentice-Hall, Inc. 12

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 © 2009 Prentice-Hall, Inc. 13

Network Topologies • The physical layout of computers, transmission media, and other components • Types of network topologies – Bus topology – Ring topology – Star topology – Hybrid topology © 2009 Prentice-Hall, Inc. 14

Bus Topology • All nodes are connected in sequence on a single cable • Used most often on 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” © 2009 Prentice-Hall, Inc. 15

Ring Topology • Nodes are laid out in a ring • Token (data packet) flows in one direction from device to device • Recent versions have data transfer rates up to 100 Mbps © 2009 Prentice-Hall, Inc. 16

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 © 2009 Prentice-Hall, Inc. 17

Avoiding Data Collisions on an Ethernet Network © 2009 Prentice-Hall, Inc. 18

Transmission Media • The routes data takes to flow between devices on a network • Wired • Wireless © 2009 Prentice-Hall, Inc. 19

Choosing a Cable • • Maximum run length Bandwidth Bend radius Cable cost Cable and installation costs Susceptibility to interference Signal transmission methods © 2009 Prentice-Hall, Inc. 20

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 5 E: Bandwidth 200 Mbps – Cat 6: Bandwidth 1 Gbps – No foil layer © 2009 Prentice-Hall, Inc. STP 21

Coaxial Cable • Four components – Copper core – Nonconductive insulating material – Braided metal – Plastic cover © 2009 Prentice-Hall, Inc. 22

Fiber-Optic Cable • Components include – Glass or plastic fibers – Cladding – Outer jacket • Uses light impulses to transmit data • Immune to interference © 2009 Prentice-Hall, Inc. 23

Wireless Media 802. 11 Standard • Wi-Fi, short for Wireless Fidelity – 802. 11 b – 802. 11 a – 802. 11 g – Super G – 802. 11 n © 2009 Prentice-Hall, Inc. 24

Network Operating Systems (NOS) • Provide the protocol that controls the communication between devices on the network • Many modern OSs include NOS client software • Major network operating systems – – – Windows Server 2003 UNIX Novell Net. Ware © 2009 Prentice-Hall, Inc. 25

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 © 2009 Prentice-Hall, Inc. 26

Network Navigation Devices • Media Access Control (MAC) address – Six two-digit numbers (01: 40: 87: 44: 79: A 5) – Physical address of network adapter – Internal network identification • Repeaters and Hubs – Amplify signals and retransmit them © 2009 Prentice-Hall, Inc. 27

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 © 2009 Prentice-Hall, Inc. 28

Network Security Threats • Human errors and mistakes – Accidents and mistakes • Malicious human activity – Current and former employees hacking or planting viruses • Natural events and disasters – Hurricanes, floods, fire © 2009 Prentice-Hall, Inc. 29

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 © 2009 Prentice-Hall, Inc. 30

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 © 2009 Prentice-Hall, Inc. 31

Network Firewall Layout © 2009 Prentice-Hall, Inc. 32

Chapter 12 Summary Questions • What are the advantages of a business network? © 2009 Prentice-Hall, Inc. 33

Chapter 12 Summary Questions • How does a client/server network differ from a peer-to-peer network? © 2009 Prentice-Hall, Inc. 34

Chapter 12 Summary Questions • What are the different classifications of client/server networks? © 2009 Prentice-Hall, Inc. 35

Chapter 12 Summary Questions • What components are needed to construct a client/server network? © 2009 Prentice-Hall, Inc. 36

Chapter 12 Summary Questions • What do the various types of servers do? © 2009 Prentice-Hall, Inc. 37

Chapter 12 Summary Questions • What are the various network topologies (layouts), and why is network topology important in planning a network? © 2009 Prentice-Hall, Inc. 38

Chapter 12 Summary Questions • What types of transmission media are used in client/server networks? © 2009 Prentice-Hall, Inc. 39

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? © 2009 Prentice-Hall, Inc. 40

Chapter 12 Summary Questions • How do network adapters enable computers to participate in a client/server network? © 2009 Prentice-Hall, Inc. 41

Chapter 12 Summary Questions • What devices assist in moving data around a client/server network? © 2009 Prentice-Hall, Inc. 42

Chapter 12 Summary Questions • What measures are employed to keep large networks secure? © 2009 Prentice-Hall, Inc. 43