Technology in Action 12282021 2007 PrenticeHall Inc 1

Technology in Action 12/28/2021© 2007 Prentice-Hall, Inc. 1

Technology in Action Chapter 12 Behind the Scenes: Networking and Security 12/28/2021© 2007 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 Types of transmission media Network software Network adapters Moving data in a client/server network Securing networks 12/28/2021© 2007 Prentice-Hall, Inc. 3

Networking Advantages • Networks – Increase productivity – Enable the sharing of hardware resources – Enable the sharing of software – Facilitate Internet connectivity 12/28/2021© 2007 Prentice-Hall, Inc. 4

Client/Server Networks • Server-based network – Clients and servers • Data flows efficiently • Servers respond to requests from clients • Servers perform specific tasks • Scalable network • Centralized 12/28/2021© 2007 Prentice-Hall, Inc. 5

Classifications of Client/Server Networks • LAN – Local area network – Computers linked together over a small geographic region 12/28/2021© 2007 Prentice-Hall, Inc. 6

Classifications of Client/Server Networks • WAN – Wide area network – Computers linked over large geographic locations • MAN – Metropolitan area network – Computers linked together within a city or county 12/28/2021© 2007 Prentice-Hall, Inc. 7

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 12/28/2021© 2007 Prentice-Hall, Inc. 8

Constructing Client/Server Networks • • Servers Network topologies Transmission media Network operating system (NOS) • Network adapters • Network navigation devices 12/28/2021© 2007 Prentice-Hall, Inc. 9

Servers • Number and type of servers depend on network size and workload • Dedicated server – Performs one specific function • Authentication server – Keeps track of network logins and services available • File server – Stores and manages files 12/28/2021© 2007 Prentice-Hall, Inc. 10

Dedicated Servers • Print server – Manages client-requested printing jobs – Creates print queue (prioritizes print jobs) • Applications server – Acts as a storage area for application software • Database server – Provides clients with access to database information • E-mail server – Processes and delivers in-coming and outgoing e-mail 12/28/2021© 2007 Prentice-Hall, Inc. 11

Dedicated Servers • Communications server – Handles communications between networks including the Internet – Often the only device on the network directly connected to the Internet • Web server – Hosts a Web site available through the Internet 12/28/2021© 2007 Prentice-Hall, Inc. 12

Network Topologies • The physical layout of computers, transmission media, and other components • Types of network topologies – Bus topology – Ring topology – Star topology – Hybrid topology 12/28/2021© 2007 Prentice-Hall, Inc. 13

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” 12/28/2021© 2007 Prentice-Hall, Inc. 14

Ring Topology • Nodes are laid out in a ring • Token (data packet) flows in one direction from device to device 12/28/2021© 2007 Prentice-Hall, Inc. 15

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 signal addressed to it 12/28/2021© 2007 Prentice-Hall, Inc. 16

Avoiding Data Collisions on an Ethernet Network 12/28/2021© 2007 Prentice-Hall, Inc. 17

Transmission Media • The routes data takes to flow between devices on a network • Wired • Wireless – Wireless Fidelity (Wi-Fi) – Uses radio waves – 802. 11 standard 12/28/2021© 2007 Prentice-Hall, Inc. 18

Choosing a Cable • • Maximum run length Bandwidth Bend radius Cable cost Installation costs Susceptibility to interference Signal transmission methods Comparison of Characteristics of Major Cable Types Cable Characteristics Twisted Pair (Cat 6) Coaxial (Thin. Net) Coaxial (Thick. Net) Fiber Optic Maximum Run Length 328 feet (100 m) 607 feet (185 m) 1, 640 feet (500 m) Up to 62 miles (100 km) Bandwidth 1, 000 Mbps 100 Mbps to 2 Gbps Bend Radius (Flexibility) No limit 360 degrees/foot 30 degrees/foot Cable Cost Very low Low Moderate High Installation Cost Very low Low Slightly higher than Thin. Net Most expensive because of Installation training required Susceptibility to Interference High Low Very low None (not susceptible to EMI and RFI) 12/28/2021© 2007 Prentice-Hall, Inc. 19

Twisted Pair Cable • Pairs of copper wire twisted around each other • Twists make the wires less susceptible to interference • Shielded twisted pair (STP) UTP – Layer of foil shielding • Unshielded twisted pair (UTP) – Cat 5 E: Bandwidth 200 Mbps – Cat 6: Bandwidth 1 Gbps – No foil layer 12/28/2021© 2007 Prentice-Hall, Inc. STP 20

Coaxial Cable • Four components – Copper core – Nonconductive insulating material – Braided metal – Plastic cover 12/28/2021© 2007 Prentice-Hall, Inc. 21

Fiber-Optic Cable • Components include – Glass or plastic fibers – Cladding – Outer jacket • Uses light impulses to transmit data • Immune to interference 12/28/2021© 2007 Prentice-Hall, Inc. 22

Wireless Media 802. 11 Standard • Wi-Fi, short for Wireless Fidelity – 802. 11 b - first cost-effective wireless devices. – 802. 11 a, 802. 11 g – bandwidth increased to 54 Mbps – Super G -bandwidth to 108 Mbps – 802. 11 n - will support higher throughput and greatly increased range 12/28/2021© 2007 Prentice-Hall, Inc. 23

Network Operating Systems (NOS) • Provide the protocol that controls the communication between devices on the network • Major network operating systems – – – Windows Server 2003 UNIX Novell Net. Ware 12/28/2021© 2007 Prentice-Hall, Inc. 24

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 12/28/2021© 2007 Prentice-Hall, Inc. 25

Network Navigation Devices • Media Access Control (MAC) address – Six 2 -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 12/28/2021© 2007 Prentice-Hall, Inc. 26

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 12/28/2021© 2007 Prentice-Hall, Inc. 27

Network Security • Authentication – User ID and password used to access the network • Access privileges – Enable access to certain network systems • Physical protection measures – Restrict physical access to sensitive network equipment – Magnetic card readers – Biometric access devices 12/28/2021© 2007 Prentice-Hall, Inc. 28

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 12/28/2021© 2007 Prentice-Hall, Inc. 29

Network Firewall Layout 12/28/2021© 2007 Prentice-Hall, Inc. 30

Chapter 12 Summary Questions • What are the advantages of a business network? 12/28/2021© 2007 Prentice-Hall, Inc. 31

Chapter 12 Summary Questions • How does a client/server network differ from a peer-to-peer network? 12/28/2021© 2007 Prentice-Hall, Inc. 32

Chapter 12 Summary Questions • What are the different classifications of client/server networks? 12/28/2021© 2007 Prentice-Hall, Inc. 33

Chapter 12 Summary Questions • What components are needed to construct a client/server network? 12/28/2021© 2007 Prentice-Hall, Inc. 34

Chapter 12 Summary Questions • What do the various types of servers do? 12/28/2021© 2007 Prentice-Hall, Inc. 35

Chapter 12 Summary Questions • What are the various network topologies? 12/28/2021© 2007 Prentice-Hall, Inc. 36

Chapter 12 Summary Questions • What types of transmission media are used in client/server networks? 12/28/2021© 2007 Prentice-Hall, Inc. 37

Chapter 12 Summary Questions • What software needs to be running on computers attached to a client/server network? 12/28/2021© 2007 Prentice-Hall, Inc. 38

Chapter 12 Summary Questions • How do network adapters enable computers to participate in a client/server network? 12/28/2021© 2007 Prentice-Hall, Inc. 39

Chapter 12 Summary Questions • What devices assist in moving data around a client/server network? 12/28/2021© 2007 Prentice-Hall, Inc. 40

Chapter 12 Summary Questions • What measures are employed to keep large networks secure? 12/28/2021© 2007 Prentice-Hall, Inc. 41