Exploring Networking and Security: Client/Server Architecture and Topologies

1. Technology in Action 1

2. Technology in Action Chapter 12 Behind the Scenes: Networking and Security

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 • Types of transmission media • Network software • Network adapters • Moving data in a client/server network • Securing networks

4. Networking Advantages • Networks • Increase productivity • Enable the sharing of hardware resources • Enable the sharing of software • Facilitate Internet connectivity

5. 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

6. Classifications of Client/Server Networks • LAN • Local area network • Computers linked together over a small geographic region

7. 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

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

9. Constructing Client/Server Networks • Servers • Network topologies • Transmission media • Network operating system (NOS) • Network adapters • Network navigation devices

10. 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

11. 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 incoming and outgoing e-mail

12. 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

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

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”

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

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 signal addressed to it

17. Avoiding Data Collisions on an Ethernet Network

18. 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

19. Maximum run length Bandwidth Bend radius Cable cost Installation costs Susceptibility to interference Signal transmission methods Choosing a Cable

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 5E: Bandwidth 200 Mbps • Cat 6: Bandwidth 1 Gbps • No foil layer UTP STP

21. Coaxial Cable • Four components • Copper core • Nonconductive insulating material • Braided metal • Plastic cover

22. Fiber-Optic Cable • Components include • Glass or plastic fibers • Cladding • Outer jacket • Uses light impulses to transmit data • Immune to interference

23. Wireless Media802.11 Standard • Wi-Fi, short for Wireless Fidelity • 802.11b – first cost-effective wireless devices. • 802.11a, 802.11g – bandwidth increased to 54 Mbps • Super G – bandwidth to 108 Mbps • 802.11n – will support higher throughput and greatly increased range

24. 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 NetWare

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

26. Network Navigation Devices • Media Access Control (MAC) address • Six two-digit numbers (01:40:87:44:79:A5) • Physical address of network adapter • Internal network identification • Repeaters and Hubs • Amplify signals and retransmit them

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

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

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

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

31. Network Firewall Layout

32. Chapter 12 Summary Questions • What are the advantages of a business network?

33. Chapter 12 Summary Questions • How does a client/server network differ from a peer-to-peer network?

34. Chapter 12 Summary Questions • What are the different classifications of client/server networks?

35. Chapter 12 Summary Questions • What components are needed to construct a client/server network?

36. Chapter 12 Summary Questions • What do the various types of servers do?

37. Chapter 12 Summary Questions • What are the various network topologies?

38. Chapter 12 Summary Questions • What types of transmission media are used in client/server networks?

39. Chapter 12 Summary Questions • What software needs to be running on computers attached to a client/server network?

40. Chapter 12 Summary Questions • How do network adapters enable computers to participate in a client/server network?

41. Chapter 12 Summary Questions • What devices assist in moving data around a client/server network?

42. Chapter 12 Summary Questions • What measures are employed to keep large networks secure?