Computer Networks:

Physical Layers

Data link Layer(DLL)

Network Layer

Transport Layer:

Session and Presentation Layer:

Application Layer:

Basis of networking

Systems that are interconnected with each other then this is called networks.

Network are of two types:

open system
close system

Open systems :

Open systems are the systems in which the system is ready to connect mode that is these systems are online or able to connect easily.

Closed systems:

Closed systems are the system that are not available for connect as they are not connected to the network.

Computer Networks:

computer networks are systems or computers that are interconnected with each other through a network.

Types of computer networks are:

PAN:

It stands for personal area network.
PAN network personal area network used for communicating among computers devices close to one person.
PAN connection standard up to 10 meters.
Examples of devices that are used in Pen are personal computers fax machine, telephone

LAN:

Local area network.
A local area network is a network that connects computers and devices in a limited geographical area such as homes, schools, and computer libraries.
Local area networks are mostly privately owned.

Advantages of local area network:

High speed
Small in size
Individual works space

Disadvantages of local area network:

Equipment and Support are costly
Some types of hardware may not supportive

MAN:

Metropolitan Area Network
Metropolitan Area Network larger than LAN and smaller than WAN
It is within 100 KM.

Advantages of metropolitan area network:

MAN act like a backbone for larger network
MAN helps the transmission of data in both directions simultaneously

Disadvantages of Metropolitan Area Network:

MAN required more cable.
Difficult to make the system secure.

WAN:

WAN wide area network
Wide area network is a computer network that covers and last geographical area such a city or country.
Wide area network are private or public owned.

Advantages of Wide area network:

Easy of communication
Large network cover
Larger audience

Disadvantages of Wide Area Network:

WAN slow in speed
WAN is difficult to maintain and complex
It is very costly
WAN is a big and complex problem
WAN is not secure