Understanding Networks I

Objectives Compare client and network operating systems Learn about local area network technologies, including Ethernet, Token Ring, FDDI, and wireless Use the OSI model to understand networking Learn how network computers and servers are addressed

Operating Systems on the Network A desktop computer requires an operating system, such as Windows 98, Windows 2000, or Windows XP, to manage its application, hardware, and connection to the network. The operating system is also responsible for enabling the computers on the local area network (LAN) to share their resources. The term resources refers to any files, databases, or printers installed on or attached to a computer.

Operating Systems on the Network (Continued) In a peer-to-peer model, several computers using different operating systems in a small business or home can be connected to form a small LAN. The process of entering a correct user ID and password and gaining access to a computer is called authentication, validation, or logging on. A user account is a collection of all of the information that pertains to a user on a computer.

Operating Systems on the Network (Continued) A network operating system (NOS), such as Windows Server 2003, Windows 2000 Server, UNIX, or Novell NetWare can be installed on a server and used to manage network resources, including user accounts, printers, and file sharing across the LAN. In a client/server model, sometimes called a domain model, a server is used to control which resources on the LAN are shared, and who can access these resources.

Windows NT Workstation, Windows 2000 Professional, and Windows XP One of the oldest that is still in use is Windows NT. It offers two operating systems, Windows NT Workstation and Windows NT Server. Windows NT Workstation does not have the Device Manager user interface.

Windows NT Workstation, Windows 2000 Professional, and Windows XP (Continued) The Windows 2000 OS family has four different operating systems, depending on your needs: Windows 2000 Professional, Windows 2000 Server, Windows 2000 Advanced Server, and Windows 2000 Datacenter Server. Windows XP comes in three different operating systems: Windows XP Professional, Windows XP Home Edition, and Windows XP 64-Bit Edition.

Linux Linux is very different from Windows. To evaluate Linux as an operating system, you need to understand the difference between an operating system kernel and an operating system shell. The operating system kernel is the part of the operating system that interfaces with applications, software cannot command the kernel directly, but must go through a command interface called the shell.

Linux (Continued) In Windows, the GUI shell is the default shell. If you want a command-line shell, you must open the Command Prompt window. In contrast, Linux and UNIX use a command-line shell as the default shell.

Macintosh Operating System Several versions of the Macintosh operating system (MacOS) are available for Macintosh computers, the latest being Mac OS X (ten). OS X provides easy access to the Internet and allows any Macintosh computer to become a Web server for a small network. The Mac OS uses a suite of networking protocols called AppletTalk, but also supports the networking protocol suite TCP/IP so it can access the Internet.

Network Protocols In addition to one or more operating systems, a network also requires a network protocol so all computers on the network can communicate. To communicate, all computers including the NOS on the server, must use the same network protocol. The selected network protocol must be supported by every operating system on the network.

Network Operating Systems Some criteria to consider when selecting a NOS are as follows: –Reliability– Performance –Adaptability– Affordability –Security– Scalability –Ease of use and ease of installation

Network Operating Systems (Continued) A domain is a centralized administrative system that uses a database to group and manage network resources, such as users, computers, printers, and additional network devices. The domain controller authenticates user logons, applies security policies, manages shared resources, and maintains the directory database used by all elements on the LAN.

Windows NT Server and Windows NT Enterprise Server One Windows NT Server computer is designated as the primary domain controller (PDC), which stores and controls a database of user accounts, group accounts, and computer accounts. This database is called the directory database or the Security Accounts Manager (SAM) database. Each computer with a backup of the directory database is called a backup domain controller (BDC).

Windows 2000 The other three Windows 2000 operating systems are: –Windows 2000 Server –Windows 2000 Advanced Server –Windows 2000 Datacenter Server A Windows 2000 Server domain is organized differently from a Windows NT domain because Windows 2000 Server does not use backup domain controllers.

Windows 2000 (Continued) Windows 2000 uses one or more domain controllers that replicate the database among themselves. Active Directory is a centralized system that controls computer and user configuration settings, security settings, and access to resources on a LAN. It uses a hierarchical organization that provides the administrator with a single place for all system administration, including user and computer configuration and management.

Windows Server 2003 A Windows Server 2003 domain is organized in much the same manner as a Windows 2000 Server domain. Windows Server 2003 keeps lists of resources on the network in an Active Directory database.

Novell NetWare NetWare by Novell, Inc. was, for many years, the tried-and-true, industry- accepted solution to LAN management. In versions of NetWare up to 5.0, the default protocol is a suite of protocols collectively called IPX/SPX, which also is supported by Windows 98, Windows NT Workstation, Windows 2000 Professional, and Windows XP.

Novell NetWare (cont’d) The IPX portion of the protocol is responsible for routing, and the SPX portion of the protocol manages error checking, similar to the way TCP manages error checking and IP manages routing on a TCP/IP network.

UNIX and Linux UNIX was the first, and still is the most popular, NOS for midsize servers responsible for supporting thin clients. Linux was mentioned earlier as an operating system for a personal computer, but is quickly becoming a viable option as a NOS. Red Hat, Inc. sells an impressive version of Linux that has proven to be competitive as a NOS for Internet services.