Computer Networks

1. Network Classification and reference மொதேல்ஸ்

2. Data Transmission and multiplexing

3. Medium Access control and data link Layers

4. Network, Transport and Applications Layer.

Classification and reference Models;

Local Area Network (LAN)

Metropolitan Area Network (MAN)

Wide Area Network (WAN)

Reference Model; (OSI open System Interface)

Physical Layer

Data Link Layer

Network Layer

Transport layer

Session Layer

Presentation Layer

Application Layer

Transmission Terminology;

Data Transmission occurs between transmitters and receives over some transmission medium.

Transmission media may be classified;

• Guided

• Unguided

In both cases, communication is in the form of electromagnetic waves with guided media, the waves are guided along a physical path examples of guided media are twisted pair, coaxial cable and optical fiber.

Time-Domain Concepts

As a function of time, an electromagnetic signal can be either continuous or discreet a signal is one in which the signal intensive varies in smooth fashion.

Frequency Domain concept

In practice an electromagnetic signal will be made up of much frequency. It can be shown using a discipline known as Fourier analysis that any signal is made up of components at various frequencies.