Networking Basics

Local area network (LAN)
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Networking Basics
Topics Covered
1. Computer Networks
2. Local Area Network Advantages
 Cost Savings
 Time Savings
 Centralized Data
 Security
 Fault Tolerance
 Communication
3. Types Of Network Operating Systems
 Peer-to-Peer Networks
 LANtastic
 Windows for Workgroups and Windows 95
 Windows NT Workstation
 Client-Server/ Centrix type
 NetWare 3.12
 NetWare 4.1
 Banyan VINES
 Windows NT Server
4. Network Components
 Hardware Components
 The Server
 The Client Workstation
 Network Interface Card
 The Cable System
 Uninterruptible Power Supply
 Tape Backup
 Network Printers
 Software Components
 Network Interface Card Drivers
 Protocol Stacks
 Network Operating System
 Client Software
 The Netware Server
 Performance
 Fault Tolerance
 Security
 Login Security
 Trustee assignments
 Client Support
5. Selecting A Network
 Defining Network Needs
 Network Size
 Client Workstations
 Network Use
 Centralized Storage
 Selecting a Network Operating System
Local area network (LAN)
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The Certified Novell Administrator (CNA)
Understanding Netware Components And Commands
Supporting Client Workstation Environments
Managing Novell Directory Services
Managing The Network File System
Establishing And Maintaining Network Users And Security
Setting Up And Maintaining Network Printing
Loading And Updating Application Software
Creating An Automated User Environment
Developing And Implementing A Backup And Recovery System
Managing The Server And Monitoring Network Performance
Supporting Network Communications
Chapter Summary
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When two or more computers are connected so that they can communicate, share the
resources with each other, a computer network is created. A computer network that
exists in one location is called a local area network (LAN). If two or more LAN in different
geographic locations are tied together, a wide are network (WAN) is created.
While distributed processing can be performed by stand-alone computers not connected
by a network, a LAN offers many advantages by sharing resources and improving
communications. These advantages make distributed processing a strong competitor of
traditional centralized minicomputer and mainframe computer systems, the traditional
means of sharing resources and communicating between users.
 Fault Tolerance
When data is stored on individual workstations there is an increased probability of data
loss due to operator error, software bugs, computer viruses, or hardware failure on the
workstation. Data stored on the network file servers can be placed on microcomputers
that are specially designed and configured to provide protection against loss of data due
to software or hardware problems. This is called fault tolerance.
 Communication
The high-speed communication between network computers provided by a LAN creates
opportunities for major changes in office management. For example, workgroup-oriented
applications such as electronic mail and scheduling are commonly used on LANs.
Electronic mail (e-mail) applications enable users to send messages and files directly to
other users on the LAN.
The network operating system (NOS) is the software that controls network services.
Depending upon their design, NOSs can be defined as either peer-to-peer or ClientServer/ Centrix type. Peer-to-peer NOSs enable workstations to communicate and share
data with each other without the need for a dedicated file server computer. Client-Server/
Centrix type NOSs use one computer as a dedicated file server, which acts as a central
storage unit for client workstations. Netware is a Client-Server/ Centrix type operating
system because its operation depends upon the existence of a dedicated Netware
 Peer-to-Peer Networks
In peer-to-peer networks, each computer can be both a server and a client workstation,
allowing any computer to share its files with other users on the network. Each computer
can also function as a print server, enabling other users to share its printer. The main
advantage of peer-to-peer NOSs is the ability to implement low-cost networks by saving
the expense of dedicating a computer as a server. In addition, peer-to-peer systems
allow users in workgroups to share data files and to communicate easily with each other.
In theory this reduces the burden on the network administrator by placing more
responsibility for data sharing in the hands of the users.
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However, large peer-to-peer networks can be very difficult to administer because shared
data can exist in several locations, making it more difficult to retrieve, secure, and back
up. For example, if workstations containing data needed by other users fails to boot its
system or shuts down unexpectedly, other users can lose data or will not be able to
access the information they need. In this section you will learn about several peer-topeer NOSs as well as their advantage and disadvantages when compared to Novell Net
 Client-Server/ Centrix type Network
In a Client-Server/ Centrix type network, file servers running specialized software are
used to provide services to client workstation computers instead of having the
workstations share data among themselves. As a result, Client-Server/ Centrix type
networks, such as those using NetWare, provide the advantages of centralized data
storage, reliability, and high performance that are not currently attainable with peer-topeer networks. One reason for the increased performance and reliability of Client-Server/
Centrix type networks such as Netware is that a file server’s hardware can be specialized
to perform the function of file sharing by providing multiple high-speed disk channels
along with a large memory capacity for file caching.
Windows NT Server
The Windows NT sever Client-Server/ Centrix type operating system provides client
workstations with centralized and highly fault-tolerant high –speed access to data. The
advantages of Windows NT are that it provides centralized management of multiple
servers through the familiar Windows environment and that it supports access to TCP/IP
and Netware servers as well as mainframe computers. A final advantage is its
usefulness as an application server, a server that runs the server portion of client/ server
applications. Many vendors offer client/server applications designed to run on the
Windows NT server.
Many network administrators are using Netware as their main network operating system
for file and print services while using Windows NT server as application servers.
The Client Workstation
Generally, each computer that is attached to the network for the purpose of running user
applications is referred to as a client workstation.
Network Interface Card
As defined previously, a LAN is basically a system that enables computers of different
types to communicate and share data.
A network interface card (NIC) is installed in each computer attached to the network,
including the servers. The NIC allows the computer to be attached to the network cable
system and is responsible for the transmission and reception of data packets on the
network. A packet consists of 500 to 4,200 bytes of formatted data that is framed with
control bits identifying the address of the computer it is being sent to and the bits for error
checking (data, address, error check).
The cable system
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A network’s cable system is the highway through which information travels from one
computer to another. A cable system consists of the wiring that connects the computers
in the network.
Network Interface Card Drivers
Protocol Stacks
The protocol stack is the software used to format the requests and information packets
that are transmitted on the network.
Network Operating System
Each server and client workstation must have a network interface card to attach it to the
cable system and to communicate on the network. A network interface card driver is
software that contains the instructions that allow the processor on the computer to control
card functions and interface with the application software.
Netware 3.1x is a 32-bit dedicated NOS that introduced the ability to load and unload
programs called NetWare loadable Modules (NLMs). This enabled network
administrators to add or delete hardware drivers and additional network services without
shutting down the server. Netware 4.0x was an earlier version of Netware 4.1x that
contained many of the same features, including NDS, but was not widely implemented
because of the scope of the changes it introduced combined with some problems that
were finally fixed in Netware 4.1.
The ability to provide faster support for workstations will become even more important as
servers are increasingly used to store large documents, images, and multimedia files.
Similarly, the increasing use of application servers to run the server portion of
client/server applications is requiring more processing power from the server itself.
Client Software
Client workstations require the following components:
1. Their own operating systems such as DOS, OS/2, Windows 95/ 98, Windows NT,
or Macintosh system 9 to control local devices and run application software.
2. Client workstations driver software to control the network interface card
3. Requester and protocol software programs to format and send requests for
network file and print services to the server; the requester program works closely
with DOS to provide access to network services.
As explained earlier in this chapter, the main function of a server is to provide file and
printer services to client workstations. As a result, the server can be enhanced with
specialized hardware and software to improve performance, security, and reliability
beyond what can be expected from a peer-to-peer network operating system.
The performance of a server is determined by how fast it can respond to requests for
data from client workstations. Therefore, the major factors that affect the server’s
performance are its ability to keep frequently used information in memory, the speed
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of its disk system, and, if the first two are adequate, the speed of its processor unit.
Some of the performance features of Netware are discussed in topic 2.
Fault Tolerance
Login security requires all users of the server to provide a valid user name and
optional password before being given access to the network.
Trustee assignments
Preventing unauthorized access to information on the server is one of the most
important responsibilities of a network administrator.
Login security
Fault Tolerance can be defined as the ability of a system to continue to operate
satisfactorily in the event of errors or other problems.
Trustee assignments enable you to assign privileges, called trustee rights, to
Netware users in order to allow them to perform certain function on the network.
Trustee assignments form the basis for Novell Directory Services security, which
controls access to Novell Directory Services (NDS). NDS is Novell’s system for
managing network resources such as printers and servers. Trustee assignments are
also the basis for file system security, which controls access to the network file
system (the directory structure of the hard drive and the files in that directory
structure). A newly created user has no rights to access any data stored on a
Netware server until you provide that user with rights to use certain parts of a file
system on a Netware server in your network.
Client Support
Because a Netware server runs its own network operating system, it is not dependent
on a specific type of client environment (unlike peer-to-peer networks) and can
support many types of workstations.
Selecting a network system for an organization involves three steps:
1. Deciding on the type of network operating system to use
2. Determining the cable system that will best support the needs of the network
3. Specifying any computer hardware that will be needed to implement servers and attach
workstations to the network.
 In this section you will learn about the criteria you should consider when developing a
recommendation for a network operating system. In topics 2 and 3 you will learn
about computer hardware options and cable configurations that you will need to know
when recommending and implementing a new network or maintaining an existing
 Defining Network Needs
Before recommending or justifying a network operating system, you first need to
analyze the processing needs of the organization and determine how the network will
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support them. The processing needs of an organization that affect the type of
network operating system to be selected include
 number of users,
 diversity of workstations,
 type of applications to be supported, and
 the need for centralized data.
Network Size
Client Workstations
The types of client workstations that will be attached to the network are another factor
to consider in determining the type of network operating system to be selected.
Peer-to-peer networks are best used in networks in which all the attached clients are
running the same type of operating system. For example, if all workstations will run
windows, the Windows 95 system could be an attractive alternative, provided it meets
the other processing needs of the network. If the client workstations are running a
combination of DOS and windows, the LANtastic or a Client-Server/ Centrix type
operating system such as Netware 4.1 might be the best choice, depending upon the
organization’s other processing needs.
Network Use
An important consideration in determining whether to use a peer-to-peer or ClientServer/ Centrix type network operating system is the number of workstations that will
be attached to the network. As a general rule, fewer the users, the more likely a
peer-to-peer network will meet the needs of the organization. In addition to the size
of the current network, you also need to look at the future growth of the organization
and how this will affect the network system. If you think that the organization will
expand in the next few years to include more users requiring heavy-duty file and
printer sharing in order to support such applications as desktop publishing and CAD,
you might want to recommend a client–server/ centrix type network operating system.
Certain common uses of networks, such as printer sharing and e-mail routing, have
small disk storage needs and can run nicely on peer-to-peer networks. For example,
if an organization plans to use its network to support workgroup-oriented software
such as e-mail and scheduling with some sharing of files and printers within small
workgroups, a peer-to-peer operating system that supports its workstation operating
systems might be the best choice.
If an organization will be running applications that require fast access to large
network data files such as desktop publishing, document imaging, and multimedia
presentation packages, a Client-Server/ Centrix type network such as Netware
should be selected in order to provide reliable, high-speed access to large disk
systems consisting of gigabytes of data storage.
If the network is using a client/server application, then a Client-Server/ Centrix type
network with an application server is necessary. The Windows NT server
environment provides a good platform for serving applications because the operating
system is designed to support application development.
Centralized Storage
 Another important consideration in selecting a network operating system is the need for
the network to contain centralized storage for files and documents. If an organization’s
employees use word processors and spreadsheet programs to access common
documents and files, a client-sever network system will provide them with consistent and
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reliable shared storage areas that can be routinely backed up in order to provide for
disaster recovery.
Client-Server/ Centrix type environments are also the best choice when users in an
organization need access to large centralized databases containing inventory and
customer information. These database files should be placed on a dedicated file server
or application server in order to take advantage of the speed associated with file caching
and the assurance of high reliability and fault tolerance that can be gained by mirroring or
duplexing the disk drives.
 Selecting a Network Operating System
The flowchart shown in Figure illustrates how to analyze the network processing needs of
an organization to help select a network operating system.
As shown in the flowchart, the number of user workstations to be attached to the network
is the first consideration. If there are fewer than 15 workstations, a peer-to-peer system
will probably be the best network alternative. However, if several of these workstations
will be working with large files that need to be shared on the network, such as those used
by departments running computer aided design applications, a Client-Server/ Centrix type
network operating system is preferable. The choice of the peer-to-peer network
operating system will also depend on the type of operating systems used by client
When the number of users exceeds 15, the need for centralized data typically becomes
an important factor in choosing between a Client-Server/ Centrix type and peer-to-peer
system. If the network will be used mostly for sharing printer and personal
communication, you will need to consider the operating systems that the client
workstations will be running. If client workstations will be running different types of
operating system, Netware is usually the best operating system choice because it can be
configured to support communications and file sharing between different client operating
When centralized data storage is a major function of the network, a Client-Server/ Centrix
type system such as Netware or Windows NT Server is the best choice because it
provides a secure and efficient platform that helps ensure that data will be available at all
times. When large database or multimedia files that are critical to an organization’s
operation need to be accessed from a centralized server, Netware 4.1x is generally the
best choice, depending upon the number of servers. In most situations in which
performance, security, and reliability are a must, Netware is probably the best choice
because it has been used extensively for many years and its performance and
compatibility with many applications are well established. Other Client-Server/ Centrix
type environments, such as Windows NT server, are newer to the marketplace and
should be considered and researched carefully to determine their performance and
compatibility in the proposed network environment.
Today many network administrators are gaining the best of both peer-to-peer and ClientServer/ Centrix type networks by implementing networks consisting of combinations of
network operating systems. For example, a Netware Client-Server/ Centrix type network
can include clients running Windows 95, while Windows NT server is used to provide
access to certain Windows NT-based client/server applications. As these operating
systems gain popularity, network administrators will be increasingly called upon to
implement network systems, using a combination of compatible products in order to
provide the services needed by the organization’s LAN users.
The microcomputer-networking field in an exciting arena with new developments
occurring on an almost daily basis. The rapid growth of this field has created the need for
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network professionals, trained individuals who can be trusted with the responsibilities of
creating and maintaining LAN and WANs.
Although it is not a required prerequisite to take the CNA exam , Novell expects that all
CNAs understand DOS and can use DOS commands. This is even true for the Windows
95 environment because the DOS prompt is still available and DOS commands can still
be run.
One of the fundamentals a Netware administrator needs is a solid foundation in the
components that make up a Netware network and how they interoperate.
The majority of computers attached to Netware networks today run either the DOS or
Windows operating system, and therefore, as a CNA, you will need to know how to install
and configure the client software used to attach DOS or Windows workstations to the
network and establish communications.
One of the most important features in NetWare 4.1 is Novell Directory Services (NDS).
On a Netware 4.1x network, a user connects to the network itself rather than to a server
(or group of servers). This requires a comprehensive, logical network design, as well as
tools for administering the resources (such as disk space and printers) for the entire
network. Novell Directory Services (NDS) is the tool that you as a CNA will use to create,
maintain, and administer the network design and resources.
A network file system uses a directory structure to define the way in which the data
storage of your server(s) is organized.
Netware has a very sophisticated security system that enables the network administrator
to provide users with access to information while at the same time protecting special
information from unauthorized access.
Perhaps one of the most complex and demanding tasks of a network administrator is
creating and maintaining the network-printing environment.
An ongoing and important job of the network administrator is installing and upgrading
application software packages that run on the client workstations. Whenever possible
you will want to install applications on the server so they can be shared and centrally
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Before the Windows environment became popular, users had to use DOS commands to
log into the network or run software programs.
Information is the lifeblood of an organization, and as a CNA you will be the guardian of
the information stored on the local area network system. One of the worst nightmares a
CNA can have is a server crashing with the loss of all the network information stored on
its hard drives. To prevent this catastrophe, you will need to be sure your server
environment is as reliable as possible.
A Netware server has its own operating system and console commands that enable a
network administrator to control the server environment as well as run special software
called Netware Loadable Modules (NLMs) in order to perform certain tasks or add new
In addition to allowing users to share resources on a server, an important use of a LAN is
communication among users, as well as access to minicomputer or mainframe computer.
A computer network is formed when two or more computers are connected so that they
can communicate electronically with each other. Local Area Networks (LANs) are
located in one location, while Wide Area Networks (WANs) connect two or more LANs.
The network administrator is responsible for running the network. Networks use servers,
which are specialized computers that provide network services. Examples of servers are
file servers, print servers, and application servers.
Networks are becoming widespread in many organizations because they provide cost
savings by enabling users to share expensive hardware and software, time savings by
making it easier for users to work together, shared access to database and document
files, a more secure environment to protect sensitive data from unauthorized access, a
more reliable storage system to prevent loss of data and time, and a communication
system that can be used for electronic mail and scheduling applications, as well as
providing access to minicomputer and mainframe computer systems.
Network operating systems (NOSs) can be classified into two types: peer-to-peer and
Client-Server/ Centrix type. Peer –to-peer operating systems do not require a dedicated
server but they are able to share data among the client workstations. Generally, peer-topeer operating systems such as LANtastic, Windows 95, and Windows NT Workstation
are best implemented for smaller workgroups that do not require frequent access to
centralized data files. Because Client-Server/ Centrix type operating systems such as
NetWare and Windows NT Server have dedicated servers, they can be more efficient
and reliable platforms for storage of centralized files.
When selecting an operating system for your network, you need to consider such factors
as the number of users and workstations, the type of operating systems and applications
that will be used by the client workstations, and the need for high-speed centralized data
storage. In most cases in which a Client-Server/ Centrix type network is needed,
NetWare equals or exceeds the capabilities of other system such as Windows NT Server
and BanyanVINE. Because each type of operating system has certain strengths,
however, many organizations must be able to integrate combinations of network
operating systems and workstations in order to meet their network processing needs.
Windows NT Server is often chosen as the operating system for an application server.
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In order to succeed as a network administrator, you will need a good understanding of
the hardware and software components that make up a network system and how they
interoperate. The basic hardware components of a network consist of the server, cable
system, network cards, uninterruptible power supply (UPS), client workstations, and
shared printers. Printers can be added to the network by attaching them to a local printer
port on the server, attaching them remotely to a client workstation, or attaching them
directly to the network cable.
The software components of a network are:
o Driver software for network interface card (NIC);
o the protocol stack, which performs the formatting of the data transmitted between
o the DOS requester program, which provides as interface between applications
and the network; and
o the network operating system, which runs on the server computer and provides
the shared network services.
Network administration is an exciting field with a great future, and a Certified Novell
Administrator (CNA) will be in a position to grow with the industry. As a CNA, your
responsibilities will include such activities as supporting client workstation applications,
creating and maintaining the network directory structures, creating and maintaining the
Novell Directory Service (NDS) database and Directory tree, establishing network users
and security, setting up and maintaining the network printing environment, managing the
server console, maintaining a user-friendly environment, implementing a fail-safe backup
and recovery system, and supporting network communications.
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Selecting A Network Operating System
Light to
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Small to
File Size
Client type
File size
s On Server
Applications on server
NT Server
Windows NT server
s NT
NT Server
Windows NT server
Windows NT