Computer Networks - papersocean

Computer Networks:

Physical Layers

Data link Layer(DLL)

Network Layer

Transport Layer:

Session and Presentation Layer:

Application Layer:

Computer Network

Computer Network basis:

computer network simply refers to a network, it is a collection of computer and devices connected by a communication channel that facilitated communication among uses and allow users to share resources with each other.

A computer network Also sharing of resources and information among devices connected to the network.

History of Computer Network

In 1960 the advance research project agency (ARPA) funding the design of the advance research project agency network (ARPANET). For the United States department of Defence. it was the first operational computer network in the world.
Computer network is and interconnection of independent computer in some manner through communication medium to share resources like hardware software and devices

Goals /Purpose / Advantages of Computer Network

1)First programming and file sharing:
Software resources can also be used more effectively as computer system are connected to each other in network. Through computer network the programs can be easily share from one device to another we are network.

2) network resource sharing:
Network resources include printer, plotter, fax, scanner, chat rooms and storage devices which can be shared by terminal connected to the network.

3) database sharing:
A database program is an ideal application for a network and network feature called record looking let’s multiple user access simultaneously at file without redundancy and inconsistency of the data.

4) Centralise management:
Network users can be grouped in one location along the share resources attached to them for easier management.

5) facilitating communication:
Use using and network people can communicate efficiently and easily via Email, chat room telephone and video conferencing.

Component /elements of Computer Network:

To make any communication possible we need certain elements like sender, receiver, cabling and peripherals.
In addition language that is understood by both of them, this mean same set of rules that are known to sender well as the receiver called Protocol in technical language.

Sender
Receiver
Communication medium
Protocol

Sender:

Sender can be a client or a system that want to give or get the information from other system.

Receiver:
Receiver is also a computer system or a server who gets the message/ request from sender.

Communication medium:
It is a medium through which sender connect to the receiver. it can be wired if the distance between sender and receiver is less. It can be wireless if the distance between sender and receiver is much more. example satellite.

Protocol:
It is a set of rules the sender and receiver will follow

Criteria of a network:

Any network must able to meet a certain numbers of criteria the most important of these are as follows
1) performance:
Performance can be measured in many ways including transmit time and response time the performance of a network depends upon the following factors:

Number of user
Types of transmission medium
Capacity of connected hardware
Efficiency of the software

2) reliability
In addition to accuracy of delivery network reliability is measured by the frequency of failure the time it it takes for a link for a device to recover from a failure.

3) security:
Network security issue include protecting data from the unauthorised access providing security in network is difficult task as their number of people users are connected to a network