EC301 Chapter 1 (1.1)

EC301 : Computer Network

Fundamental

Noted prepared by:

Pn. Wan Fazlini Idayu binti Wan

Fakari

Chapter 1.0 Introduction to Network

CLO 1: you should be able to explain the

hardware devices to build Local Area Network

(LAN) for a specific implementation. (C2)note: C2 = comprehensive

• Chapter 1 will appear in:-

– Theory test

– Quiz (1)

3

What is a Network?

A network consists of 2 or more computers connected

together, and they can communicate and share

resources (e.g. information)

1.1 Basic Concepts And

Component Of Computer

Network

Networked Computing Relative &

Standalone Computing

Networked Standalone

Group of computers and other devices

connected by some type of transmission

media

Uses programs and data only from its

local disks and is not connected to a

network

Networks enable users to share devices

and data, collectively called a network’s

resources

Advantages of networked computing

relative to standalone computing

1. Fewer Peripherals Needed

2. Increased Communication Capabilities

3. Avoid File Duplication and Corruption

4. Lower Cost Licensing

5. Centralized Administration

6. Conserve Resources









Many devices can be connected on a network. Each computer on the

network does not need to have its own printer, scanner, or backup device.

Multiple printers can be set up in a central location and shared among the

network users. All network users send print jobs to a central print server that

manages the print requests. The print server can distribute print jobs over

multiple printers, or queue jobs that require a specific printer.









Networks provide several different collaboration tools that can be used to

communicate between network users. Online collaboration tools include e-

mail, forums and chats, voice and video, and instant messaging. With these

tools, users can communicate with friends, family, and colleagues.









A server manages network resources. Servers store data and share it with

users on a network. Confidential or sensitive data can be protected and

shared with the users who have permission to access that data. Document

tracking software can be used to prevent users from overwriting files, or

changing files that others are accessing at the same time.









Application licensing can be expensive for individual computers. Many

software vendors offer site licenses for networks, which can dramatically

reduce the cost of software. The site license allows a group of people or an

entire organization to use the application for a single fee.









Centralized administration reduces the number of people needed to manage

the devices and data on the network, reducing time and cost to the company.

Individual network users do not need to manage their own data and devices.

One administrator can control the data, devices, and permissions of users on

the network. Backing up data is easier because the data is stored in a central

location.









Data processing can be distributed across many computers to prevent one

computer from becoming overloaded with processing tasks.

Type of networks

Peer-to-pear networks Client/server network

A Peer-to-peer model can be defined as a

decentralized environment, where the user

must be assigned permissions on each

workstation in order to access any available

resources.

A client-server model can be defined as a

centralized environment, where all users,

objects, resources, and so on are

administered in a centralized location and

can, if configured, use any network

resources on any workstation on the

domain.

Computers connect with each other in a

workgroup to share files, printers, and

Internet access. This is used to connect a

small number of computers.

sends information from a client computer to

a server, which then relays the information

back to the client computer, or to other

computers on the network

There are essentially two types of network architectures—client-server and peer-to-peer.

Sketch a Peer-to-peer network• A peer-to-peer distributed network architecture is composed of

participants that make a portion of their resources (such as processing power, disk storage, and network bandwidth) available directly to their peers without intermediary network hosts or servers.

• Peers are both suppliers and consumers of resources, in contrast to the traditional client-server model where only servers supply, and clients consume.

Sketch a Client/server network• In this arrangement, a single computer called a 'server' is given

the duty to provide a particular service on behalf of one or more 'client' computers. The clients make requests to the server and the server responds to the requests.

• There are many kinds of server that include – File server - stores, handles and serves files to clients

– Print server - stores, handles and organizes printing jobs for its clients

– FTP server - provides a means to move large amounts of data

– Video server - stores and distributes video files

– Backup server - sits on the network taking periodic backups of clients.

Categories of networks

Fundamental Network Classifications

Local Area Networks (LANs):

• A local area network (LAN) is a computer network covering a small geographic area, like a home, office, or group of buildings

Wide Area Networks (WANs):

• Wide Area Network (WAN) is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries). Or, less formally, a network that uses routers and public communications links

• The largest and most well-known example of a WAN is the Internet.

• WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations

Metropolitan Area Network (MAN):

o A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.

LAN (Local Area Network)

• Allow resource sharing between computers.

– Computers

– Peripheral devices

– Transmission medium (e.g. cable)

• 3 types of topology

– Bus topology

– Star topology

– Ring topology

Figure 6-4LANs

� Hub –� a device that facilitates connection� LAN acts logically like a bus.

� Star –the dominant topology today.

Examples of Ethernet LAN Diagram

MAN (Metropolitan Area Network)

• Uses services provided by a network service provider.

(Tel. Company)

– Individual users’ computers

– Organizations’ LANs

• Many Tel. Company provide a popular MAN service

called SMDS (Switched Multimegabit Data Services)

– Prior to SMDS's arrival in 1995,

the only way to connect LANs was through

a dedicated private line.

MAN (Metropolitan Area Network)

WAN (Wide Area Network)

• The connection of individual computers or LANs over

a large area (country, world).

• User using a telephone line to connect to an ISP

(Internet Service Provider) is using a WAN.

– Negotiates fee

• ISP

• Tel. company

Wide Area Network (WAN)

Classification of networks according to its size

COMPUTER NETWORKS

SYSTEM

AREA SIZE EXAMPLE

1 Local Area Network (LAN) Small Area

(10km)

School,

laboratory, in

building

2 Metropolitan Area Network

(MAN)

Big Area

(10~50km)

City, State

3 Wide Area Network (WAN) Biggest Area

(more than

50km)

World, country,

Internet

Element of Client/server network• Client

• Server

• Workstation

• Network interface card

• Network operating system

• Node

• Connectivity device

• Backbone

• Segment

• Topology

• Transmission media


• Server

• Workstation



• Node


• Backbone

• Segment

• Topology


request and receive

information over the

network client. Client

computers also depends

primarily on the central

server for processing

activities

A computer on the network that manages

shared resources; servers usually have more

processing power, memory, and hard disk

space than clients. They run network

operating software that can manage not only

data, but also users, groups, security, and

applications on the network.


• Server

• Workstation



• Node


• Backbone

• Segment

• Topology


A personal computer

(such as a desktop or

laptop), which may or

may not be connected to

a network; most clients

are workstation

computers.

The device inside a computer that connects a computer

to the network media, thus allowing it to communicate

with other computers; many companies (such as 3Com,

IBM, Intel, SMC, and Xircom) manufacture NICs, which

come with a variety of specifications that are tailored to

the requirements of the workstation and the network.

Some connect to the motherboard, which is the main

circuit that controls the computer, some are integrated as

part of the motherboard, and others connect via an

external port. NICs are also known as network adapters.


• Server

• Workstation



• Node


• Backbone

• Segment

• Topology


The software that runs on a server and enables

the server to manage data, users, groups,

security, applications, and other

networking functions. Examples include various

types of UNIX and Linux operating

systems, Microsoft Windows Server 2003 or

Windows Server 2008, and Mac OS X Server.

A client, server, or other device that can

communicate over a network and that is

identified by a unique number, known as its

network addressers.


• Server

• Workstation



• Node


• Backbone

• Segment

• Topology


-A specialized device that allows multiple

networks or multiple parts of one

network to connect and exchange data. A

client/server network can operate

without connectivity devices. However,

medium- and large-sized LANs use them

to extend the network and to connect

with WANs.

The part of a network to which segments and

significant shared devices (such as routers,

switches, and servers) connect. A backbone is

sometimes referred to as "a network of

networks," because of its role in

interconnecting smaller parts of a LAN or

WAN.


• Server

• Workstation



• Node


• Backbone

• Segment

• Topology


A part of a network. Usually, a segment is composed

of a group of nodes that use the same

communications channel for all their traffic

refers to the way computers and peripherals are

configured to form networks. The physical layout of

a computer network. Topologies vary according

to the needs of the organization and available

hardware and expertise. Networks can be arranged

in a ring, bus, or star formation, and the star

formation is the most common. Hybrid

combinations of these patterns are also possible.

The means through which data is transmitted and

received. Transmission media may be physical, such as wire

or cable, or atmospheric (wireless), such as radio waves.

Element of Client/server network• Client - request and receive information over the network client. Client computers also depends primarily on the central server for processing

activities

• Server - A computer on the network that manages shared resources; servers usually have more processing power, memory, and hard disk space

than clients. They run network operating software that can manage not only data, but also users, groups, security, and applications on the

network.

• Workstation - A personal computer (such as a desktop or laptop), which may or may not be connected to a network; most clients are workstation

computers.

• Network interface card - The device (pronounced nick) inside a computer that connects a computer to the network media, thus allowing it to

communicate with other computers; many companies (such as 3Com, IBM, Intel, SMC, and Xircom) manufacture NICs, which come with a variety

of specifications that are tailored to the requirements of the workstation and the network. Some connect to the motherboard, which is the main

circuit that controls the computer, some are integrated as part of the motherboard, and others connect via an external port. NICs are also known

as network adapters.

• Network operating system - The software that runs on a server and enables the server to manage data, users, groups, security, applications, and

other networking functions. Examples include various types of UNIX and Linux operating systems, Microsoft Windows Server 2003 or Windows

Server 2008, and Mac OS X Server.

• Node - A client, server, or other device that can communicate over a network and that is identified by a unique number, known as its network

addressers.

• Connectivity device - A specialized device that allows multiple networks or multiple parts of one network to connect and exchange data. A

client/server network can operate without connectivity devices. However, medium- and large-sized LANs use them to extend the network and to

connect with WANs.

• Backbone - The part of a network to which segments and significant shared devices (such as routers, switches, and servers) connect. A backbone is

sometimes referred to as "a network of networks," because of its role in interconnecting smaller parts of a LAN or WAN.

• Segment - A part of a network. Usually, a segment is composed of a group of nodes that use the same communications channel for all their traffic

• Topology - refers to the way computers and peripherals are configured to form networks. The physical layout of a computer network. Topologies

vary according to the needs of the organization and available hardware and expertise. Networks can be arranged in a ring, bus, or star formation,

and the star formation is the most common. Hybrid combinations of these patterns are also possible.

• Transmission media – The means through which data is transmitted and received. Transmission media may be physical, such as wire or cable, or

atmospheric (wireless), such as radio waves.

Networking Terminology

1

Computer network topology

• Bus

• Ring

• Star

• Hybrid


• Bus

• Ring

• Star

• Hybrid

all computers are linked by a single line

of cable


• Bus

• Ring

• Star

• Hybrid

each computer or workstation is

connected to two other computers,

with the entire network forming a circle


• Bus

• Ring

• Star

• Hybrid

multiple computers and peripheral

devices are linked to a central

computer, called a host


• Bus

• Ring

• Star

• Hybrid

combine network layout types to meet their needs

EC301 Chapter 1 (1.1)

Documents

networked

linux operating

hard disk

avoid file

interconnecting

wide area

metropolitan

local area