Types and Methods of Data Transmission

This section describes the various ways data can be transmitted between devices. Understanding these methods is crucial for comprehending how networks function.

Transmission Methods

Data transmission can be broadly categorized into two main types:

• Circuit Switching: A dedicated physical path is established between the sender and receiver before data transmission begins. This path remains dedicated for the duration of the communication.
• Packet Switching: Data is broken down into small units called packets. Each packet contains addressing information and can travel independently through the network, potentially taking different routes to reach the destination.

Circuit Switching in Detail

In circuit switching, a physical connection (circuit) is established before data transmission. This circuit remains dedicated to the communication between the two devices. A telephone network is a classic example of circuit switching.

Feature	Description
Connection	Dedicated physical path
Resource Allocation	Dedicated resources during the communication
Delay	Relatively constant delay
Example	Traditional telephone networks

Packet Switching in Detail

Packet switching divides data into packets. Each packet is treated independently and can travel along different routes to the destination. The packets are reassembled at the receiving end. The Internet is the primary example of a packet-switched network.

Feature	Description
Connection	No dedicated path; packets routed independently
Resource Allocation	Resources allocated as needed
Delay	Variable delay; packets may experience different delays
Example	The Internet

Methods of Data Transmission

Data can be transmitted using various physical mediums. These methods differ in terms of speed, cost, and distance capabilities.

Wired Transmission

Wired transmission uses physical cables to transmit data.

• Twisted Pair Cable: Uses pairs of wires twisted together to reduce electromagnetic interference. Commonly used for telephone lines and Ethernet networks.
• Coaxial Cable: Uses a central copper conductor surrounded by insulation and a braided shield. Provides higher bandwidth than twisted pair. Used for cable television.
• Optical Fibre Cable: Transmits data as light pulses through glass or plastic fibres. Offers very high bandwidth and long distances. Used for long-distance communication and the Internet backbone.

Wireless Transmission

Wireless transmission uses radio waves or other electromagnetic waves to transmit data.

• Radio Waves: Used for mobile phones, Wi-Fi, and radio broadcasting.
• Microwaves: Used for satellite communication and long-distance data links.
• Infrared: Used for short-range communication, such as remote controls.
• Bluetooth: Used for short-range wireless communication between devices, such as headphones and smartphones.

Data Transmission Protocols

Protocols are sets of rules that govern how data is transmitted. They ensure reliable and efficient communication.

• TCP/IP: The fundamental protocol suite used on the Internet. TCP handles reliable data transmission, while IP handles addressing and routing.
• UDP: A connectionless protocol that is faster than TCP but less reliable. Used for applications where speed is more important than reliability, such as video streaming.