Introduction - Network Administration - Lecture Slides, Slides of Network and System Administration

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INTRODUCTION TO

COMPUTER NETWORKS

Computer Networks

Computer network connects two or more autonomous computers.

The computers can be geographically located anywhere.

Applications of Networks

Resource Sharing

Hardware (computing resources, disks, printers) Software (application software)

Information Sharing

Easy accessibility from anywhere (files, databases) Search Capability (WWW)

Communication

Email Message broadcast

Remote computing

Distributed processing (GRID Computing)

Network Topology

The network topology defines the way in which computers, printers, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.

Star & Tree Topology

The star topology is the most commonly used architecture in Ethernet LANs.

When installed, the star topology resembles spokes in a bicycle wheel.

Larger networks use the extended star topology also called tree topology. When used with network devices that filter frames or packets, like bridges, switches, and routers, this topology significantly reduces the traffic on the wires by sending packets only to the wires of the destination host.

Ring Topology

A frame travels around the ring,

stopping at each node. If a node wants

to transmit data, it adds the data as

well as the destination address to the

frame.

The frame then continues around the

ring until it finds the destination node,

which takes the data out of the frame.

Single ring – All the devices on the network share a single cable

Dual ring – The dual ring topology allows data to be sent in both directions.

Network Components

Physical Media

Interconnecting Devices

Computers

Networking Software

Applications

Networking Media

Networking media can be defined simply as the means by which signals (data) are sent from one computer to another (either by cable or wireless means).

Computers: Clients and Servers

In a client/server network arrangement, network services are located in a dedicated computer whose only function is to respond to the requests of clients.

The server contains the file, print, application, security, and other services in a central computer that is continuously available to respond to client requests.

Networking Protocol: TCP/IP