1. Categorizing Networks Gary DeRoest

2. Gary DeRoest

3. Categories • Physical scope • Method of administration • Network operating system • Network protocols • Topology • Architecture • OSI Gary DeRoest

4. Categorizing Networks by Physical Scope • Local-area network • Metropolitan-area network • Wide-area network Gary DeRoest

5. Local-area Networks (LAN) • Limited to a specific geographic area • 2 computers connected together in a home office • 500 computers computers connected together in an office building Gary DeRoest

6. Local-area Networks • Network architecture and cable type can limit the number of computers a LAN can contain. • Large LANs can be divided into workgroups. Gary DeRoest

7. Metropolitan-area Network (MAN) • Two or more LANs networked together within a city or community. • Less frequently used term. Gary DeRoest

8. Wide-area Network (WAN) • A network spanning a large geographical area. • The internet. • Private networks. • Internet vs. internet. Gary DeRoest

9. Wide-area Network (WAN) • Intranet – a private network within an enterprise using the same protocols as the Internet. • Extranet – an intranet but made accessible to customers, employees, vendors and partners. Gary DeRoest

10. Wide-area Networks (WAN) • Use of public transports such as telephone lines slow transmission speed • Modem: 50 kbps • T1, cable modem, DSL : 1 – 6 mbps • Slowest Ethernet LAN: 10 mbps Gary DeRoest

11. Wide-area Network (WAN) • Routed networks. • For a message to pass from one segment (LAN) to another, the packets must pass through a gateway. • Gateway: a specially configured computer or router which sends packets to another LAN. Gary DeRoest

12. Categorizing Networks by Method of Administration • Peer-to-peer • Each computer functions as server and client • Each computer is administered by its user • Client/server • Administration is centralized • Special network operating system (NOS) is required Gary DeRoest

13. Method of Administration • A server is a computer that makes its resources available for access by other computers on the network. • Data, software, printers … • A client is a computer that accesses the resources of the server computer. • Clients take; Servers give. Gary DeRoest

14. Method of Administration • Peer-to-peer • Each computer functions as server and client • Each computer is administered by its user • Share Level Security • Client/server • Administration is centralized • Special network operating system (NOS) is required • User Level Security Gary DeRoest

15. Method of Administration The operating systems that we think of as client or desktop operating systems – Windows 95/98, NT Workstation, and Windows 2000 Pro. – can and do function as servers when you create shares on them to enable other computers to use their resources. Gary DeRoest

16. Method of Administration • If you had a folder named WestProject that you wanted to share over the network, you must assign a name to the share. • WP, Wproj, etc. Gary DeRoest

17. Method of Administration • The share named WestProject appears in the browse list for the server named Gordian. Gary DeRoest

18. Method of Administration • Some network operating systems allow for shared resources to be “published” to the master directory. • Active directory in windows 2000. • NDS tree in Novell Netware. • This enables users to locate the shared resources without knowing which server hosts the resource. Gary DeRoest

19. Method of Administration • Telephony servers • Cluster servers • Proxy servers • Fax servers • BOOTP servers • DHCP servers • Name resolution servers • Dedicated servers • File servers • Print servers • Application servers • Logon servers • Web servers • Mail servers • News servers • Remote access servers • Terminal servers Gary DeRoest

20. Method of Administration • A daemon, in UNIX terminology, is a program that runs continuously and handles periodic requests for services. Gary DeRoest

21. Method of Administration • The term client, again refers to a device requesting services from a server such as: • Computer, printer, network device, software program • An e-mail program that runs on your desktop computer that sends requests to download new messages is often called an e-mail client. Gary DeRoest

22. Method of Administration • A workstation generally refers to mean any desktop computer running any client operating system – Windows, Linux, Macintosh, etc. • A workstation can also refer to a powerful computer used to run resource intensive application software. Gary DeRoest

23. Method of Administration • The term host also can refer to computers on a network. • With TCP/IP based networks, host can include any network device that is assigned an IP address. Gary DeRoest

24. Method of Administration • A node is a connection point on a network. • A computer • A printer • Network device Gary DeRoest

25. Characteristics of Peer-to-peer Networks • 10 computers maximum. • Inexpensive. • Windows, Linux, Macintosh. • Decentralized administration. • User accounts must be created and maintained on each node. Gary DeRoest

26. Share Level Security • Used by windows for workgroups 3.11 and windows 95/98 • A password assigned for each shared resource • To access resource, a user must provide the password for that resource • Users must remember multiple passwords Gary DeRoest

27. User Lever Security • Used by windows NT and windows 2000 • A password is assigned to each user • Access to a specific resource only if user has been assigned permissions • Users need only remember one password Gary DeRoest

28. Server-based Networks • Centralized control • NOS installed on 1+ machine • Netware, Windows NT, Windows 2000 server • User accounts maintained on server • Increased performance & throughput • Additional services provided Gary DeRoest

29. Server-based Administration • Simplified • Shared resources stored on server for easy location and backup • Requires a professional network administrator Gary DeRoest

30. Server-based Security • Inherently more secure that peer-2-peer • Requires user accounts and password • Access to resources are granted through user authentication and permissions • Network administrator assigns permissions to individual users and groups of users Gary DeRoest

31. Categorizing Networks by NOS • Windows (NT and 2000) • Netware • UNIX • Networks containing more than one server type are called hybrid networks Gary DeRoest

32. Windows Server-based Networks • Domains • Primary domain controller • Security accounts manager (SAM) • Downlevel domains • Active directory • Copies stored on each domain controller Gary DeRoest

33. Windows Server-based Networks • What clients can access Windows NT and 2000 server resources? • Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOS • Macintosh and Linux clients can access resources Gary DeRoest

34. Netware Server-based Networks • Bindery database • NDS – organize objects • Trees • Replicas • Context • Login security • File and print services Gary DeRoest

35. Gary DeRoest

36. Netware Server-based Networks • What clients can access NetWare server resources? • Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOS • Client32 software provides full functionality • Macintosh and Linux clients can access resources with appropriate client software Gary DeRoest

37. UNIX Server-based Networks • Powerful NOS developed by Bell Labs in 1969 • Linux development and other open standard software are recently becoming popular • Text based and GUI based Administration tools are available • Access granted by user ID and password • Groups are collections of users with similar access permissions which simplify administration Gary DeRoest

38. UNIX Server-based Networks • What clients can access UNIX server resources? • Dumb terminals, Linux, Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOS • Macintosh clients can access resources with appropriate client and server software Gary DeRoest

39. UNIX Server-based Networks • HP-UX • SUN solaris • AIX • SCO • etc Gary DeRoest

40. Hybrid Networks • Most medium to large networks are hybrids • All NOS provide interoperability tools • Client Services for NetWare • Gateway Services for NetWare • Microsoft NetWare client • File and print services • Macintosh services • Systems Network Architecture (SNA) • SAMBA Gary DeRoest

41. Categorizing Networks by Protocol • NetBEUI • IPX/SPX • TCP/IP • Others Gary DeRoest

42. NetBEUI • NetBIOS Extended User Interface • Network Basic Input/Output System • Provides application programming interface • Developed by IBM • Unroutable • Simple to setup – no complicated configuration • Low resource overhead • Fast Gary DeRoest

43. IPX/SPX • Internet Package Exchange/Sequenced Packet Exchange • Novell proprietary protocol • Minimal configuration • Faster performance than TCP/IP • NWLink, IPX/SPX, MacIPX Gary DeRoest

44. TCP/IP • Most popular despite being the most difficult to configure and being slow • Flexible addressing scheme – extremely routable • Almost all OS can use it • Lots of utility tools available • The protocol of the Internet Gary DeRoest

45. Others - AppleTalk • A set of protocols developed by Apple for networking Macintosh machines • LocalTalk • Slow (230.4 kbps) supports only 32 devices • EtherTalk • Used to connect to Ethernet networks • TokenTalk • Used to connect to Token Ring networks • AppleTalk networks use AppleTalk Address Resolution Protocol (AARP) to map AppleTalk addresses to Ethernet and Token Ring physical Media Access Control (MAC) addresses Gary DeRoest

46. Others - OSI • Open Systems Interconnection • Intended to replace TCP/IP • Developed by the International Organization for Standardization (ISO) isos • Improved set of protocols for less confusion and easier standardization of networking products Gary DeRoest

47. Categorizing Networks by Topology Gary DeRoest

48. Categorizing Networks by Topology • Linear Bus • Ring • Star • Mesh • Hybrid Gary DeRoest

49. Linear Bus Networks Gary DeRoest

50. Linear Bus Networks • Computers in a bus network are connected in a line from one to the next • A bus network requires termination at each end to prevent signal bounce • Usually use thick or thin coax cable and the Ethernet 10base2 or 10base5 architure Gary DeRoest