CBSE 12 CS Chapter 2 Data communication terminologies

Concept of Communication

• Communication is the process of exchanging information between two or more entities (individuals, devices, etc.).
• It involves a sender transmitting a message to a receiver through a communication medium.

Components of Data Communication

• Sender: The entity that initiates the communication and sends the message.
• Receiver: The entity that receives the message sent by the sender.
• Message: The information that is being transmitted.
• Communication Media: The physical path through which the message travels (e.g., cables, wireless signals, optical fibers).
• Protocols: A set of rules that govern how data is transmitted and received on the network. They ensure that devices can understand and interpret the information correctly.

Measuring Capacity of Communication Media

• Bandwidth: The amount of data that can be transmitted over a communication channel in a given amount of time. It is often measured in bits per second (bps). Higher bandwidth means faster data transfer.
• Data Transfer Rate: The speed at which data is transmitted, typically measured in bits per second (bps) or bytes per second (Bps).

IP Address

• Every device connected to the internet has a unique IP address.
• It's like a unique address for your computer or phone on the network.
• IP addresses allow devices to locate and communicate with each other on the internet.

Switching Techniques

• Circuit Switching:
• A dedicated communication path is established between the sender and receiver for the duration of the communication. ¹  
• Like a phone call where a direct connection is made between two phones.
• Efficient for continuous data flow, but less flexible.
• Packet Switching:
• Data is divided into small packets, each with its own destination address.
• Packets are transmitted independently over the network and may take different routes.
• More efficient for handling varying data loads and network congestion.
• Used in the internet.

In Simple Terms

• Imagine you want to send a letter to a friend.
• Communication: The act of writing and sending the letter.
• Sender: You
• Receiver: Your friend
• Message: The content of the letter
• Communication Media: The postal service
• Protocols: The format and rules for addressing and sending letters.
• Bandwidth: How much information can be carried by the postal service at once.
• Data Transfer Rate: How quickly the letter reaches your friend.
• IP Address: Your friend's address.
• Circuit Switching: Like making a phone call - a dedicated line for the entire conversation.

Packet Switching: Like sending multiple postcards, each with its own address, and they might arrive in a different order.