Objectives

To define network To identify use of network To differentiate major types of network To identify basic networking

terminologies To enumerate network considerations To identify network components &

designs

What is a Network?

A network consists of two or more computers that are linked in order to share resources (such as printers and CD-ROMs), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

Use of Network

Data Printer Application

Some of components which are the constituents of a network are: One or more servers Workstation Peripheral devices Network board Communication media Network administrator

What is a Workstation?What is a Workstation?

Workstation is a client, more Workstation is a client, more specifically it is a standalone specifically it is a standalone computer of the network. It has its computer of the network. It has its own software, data files and does own software, data files and does its own processing to expand its its own processing to expand its resources and knowledge, it may resources and knowledge, it may get connected to a network. get connected to a network.

What is a Client?What is a Client?

In English language vocabulary In English language vocabulary “client - refers to a person, who “client - refers to a person, who requested for service.”requested for service.”

In network terminology, it refers to In network terminology, it refers to the different types of terminals, or the different types of terminals, or workstations. workstations.

What is a Server?What is a Server?

A server is a LAN (Local Area A server is a LAN (Local Area Network) component that can be Network) component that can be shared by users on the LAN. The shared by users on the LAN. The three most popular servers are the three most popular servers are the file server, print server, and file server, print server, and communication server.communication server.

Different types of ServersDifferent types of Servers

File serverFile server Print serverPrint server Communication serverCommunication server

File ServersFile Servers It is a program that provides to the It is a program that provides to the

user the disks or other mass user the disks or other mass storage devices for storing and storage devices for storing and retrieving files as specified by the retrieving files as specified by the users. The program provides users. The program provides protection from unauthorized protection from unauthorized reading and writing. reading and writing.

Print ServersPrint Servers

It is a combination of hardware and It is a combination of hardware and software package which allows software package which allows anyone on the network to have anyone on the network to have access to a printing services. The access to a printing services. The hardware includes an ordinary line hardware includes an ordinary line printer and the software receives printer and the software receives and buffers a file of information, and buffers a file of information, which may come from a personal which may come from a personal computer with its own disk. computer with its own disk.

This server provides This server provides communications links external to communications links external to the LAN - that is, micro/mainframe the LAN - that is, micro/mainframe links to other networks. To links to other networks. To accomplish this service, the accomplish this service, the communication server controls one communication server controls one or more modems.or more modems.

Communication ServerCommunication Server

Disk ServerDisk Server

It primarily functions to achieve It primarily functions to achieve economy of scale by dividing a economy of scale by dividing a large disk into sections to which large disk into sections to which individual users have to access.individual users have to access.

Dedicated Server Vs Non-Dedicated Server Vs Non-dedicated Serverdedicated Server

A computer that both runs standard A computer that both runs standard programs and lets other users see its programs and lets other users see its data at the same time is said to be a data at the same time is said to be a “non-dedicated server”.“non-dedicated server”.

A computer without a human A computer without a human operator, whose only job is to share operator, whose only job is to share data and printers for others to use is data and printers for others to use is called a “dedicated server”.called a “dedicated server”.

What is a Peripheral Device?What is a Peripheral Device?

They are computer related They are computer related devices, such as local printers, disk devices, such as local printers, disk drivers and modems.drivers and modems.

Some of the most popular Some of the most popular devices are listed below:devices are listed below:

RAMRAM ModemModem Serial portSerial port Parallel portParallel port Printer spoolerPrinter spooler Accelerator Accelerator

What is a Network Board?What is a Network Board?

A network board is a circuit board A network board is a circuit board installed in each computer to allow installed in each computer to allow servers and workstation to servers and workstation to communicate with each other.communicate with each other.

What is Network Interface What is Network Interface Card?Card?

The Network Interface Card (NIC) The Network Interface Card (NIC) facilitates and controls the facilitates and controls the exchange of data between the exchange of data between the micros in a PC network (several micros in a PC network (several micros linked together).The NIC micros linked together).The NIC connects information from the connects information from the busy microprocessor, stores it, and busy microprocessor, stores it, and doles it out slowly onto the doles it out slowly onto the network wires. network wires.

What is Communication What is Communication Media? Media?

The communication media is The communication media is basically the connection or link basically the connection or link between different devices of a between different devices of a network system which can allow network system which can allow communication to occur.communication to occur.

Advantages of Installing a Advantages of Installing a NetworkNetwork

SpeedSpeed Cost Cost SecuritySecurity Centralized Resource ManagementCentralized Resource Management Resource SharingResource Sharing Electronic MailElectronic Mail Flexible AccessFlexible Access Workgroup ComputingWorkgroup Computing

Disadvantages of Installing a Disadvantages of Installing a NetworkNetwork

Expensive to InstallExpensive to Install Requires Administrative TimeRequires Administrative Time File Server May FailFile Server May Fail Cables May BreakCables May Break

1.5 Network Design

Computer networks also differ in their design.

The two types of high-level network design are called client-server and peer-to-peer.

Client-server networks Client-server networks feature

centralized server computers that store email, Web pages, files and or applications. Has at least one workstation which has configured as a network server. The server is used as a computer running the network operating system. The server controls the communication and shares the network resources. The client workstations are the individual computer to the work.

Centralized and coordinated features such as:

Log-in control Centralized backup A single uninterruptable power supply Stored procedures that follow required

company business rules

Server-Based Network/Client-Server Network

Usually more than 10

Need server Central

administration Need Admin With security Complex to

implement

Client/Workstation computer/s that

ask for a service in the network. In the Client-Server setup, client sometimes acts as server when it provides service to the other unit in the network

Peer-to-Peer Network

On a peer-to-peer network, conversely, all computers tend to support the same functions. Client-server networks are much more common in business and peer-to-peer networks much more common in homes.

two workstations connected together, workstations on a peer - to - peer network

are equal and no one is designated as the main or host computer or centralized point of control.

Peer to Peer Network

Usually less than ten in number

No central administration

Need no Admin No security Easy to

implement

1.6 What is a Network 1.6 What is a Network SystemSystem

A group of computers that can A group of computers that can communicate with each other, communicate with each other, share resources (such as hard share resources (such as hard disks and printers), allows them disks and printers), allows them to communicate with one another to communicate with one another and access remote hosts or other and access remote hosts or other network, then it is known as network, then it is known as Network System.Network System.