Switched Network

 

Switched Network

Introduction

A switched network is a network in which a device called a switch connects two or more communication links together.

The switch receives data from one link and forwards it to another link whenever needed.

Definition

A switched network is a communication network in which switches are used to forward data from one link to another.

Role of a Switch

A switch performs the task of:

  • Receiving data
  • Determining the destination
  • Forwarding the data to the correct link

In modern communication systems, switching helps multiple users communicate efficiently.

Types of Switched Networks

There are two main types of switched networks:

  1. Circuit-Switched Network
  2. Packet-Switched Network

1. Circuit-Switched Network

Introduction

In a circuit-switched network, a dedicated communication path called a circuit is established between two end systems before communication begins.

The path remains reserved during the entire communication session.

Working Principle

  • A fixed path is created between sender and receiver
  • Resources are reserved for the whole communication period
  • The connection can either be:
    • Active
    • Inactive

The switch only activates or deactivates the circuit.

Example

Traditional telephone networks are classic examples of circuit switching.

Telephone ---- Switch ===== Switch ---- Telephone

Once a call is established:

  • The communication path remains dedicated
  • Other users cannot use that reserved capacity


Characteristics of Circuit Switching

Dedicated Path

A fixed communication path exists between two devices.

Continuous Communication

Data flows continuously throughout the session.

No Storage in Switches

Switches only forward signals and do not store data.

Resource Reservation

Bandwidth is reserved even if no data is being transmitted.

Advantages of Circuit Switching

  • Continuous transmission
  • Predictable performance
  • No packet delay during communication
  • Suitable for voice communication

Disadvantages of Circuit Switching

Inefficient Resource Usage

Reserved bandwidth may remain unused.

Wastage of Capacity

Resources are occupied even during idle periods.

Less Efficient for Data Traffic

Computer communication is bursty rather than continuous.

Example from the Text

Suppose:

  • Four telephone pairs can communicate simultaneously
  • The main communication line has capacity for four calls

If:

  • Only one call is active

Then:

  • Only one-fourth of the capacity is used
  • Remaining capacity stays unused

This makes circuit switching inefficient during low traffic.

2. Packet-Switched Network

Introduction

In a packet-switched network, data is divided into small units called packets.

Each packet is transmitted independently through the network.

Working Principle

Instead of continuous communication:

  • Data is broken into packets
  • Packets are stored temporarily
  • Then forwarded toward the destination

This method is called:

Store-and-Forward Transmission

Example

Modern computer networks and the Internet use packet switching.

Computer ---- Router ==== Router ---- Computer

Routers:

  • Store packets in queues
  • Forward them when the communication line becomes available


Characteristics of Packet Switching

Data Divided into Packets

Large messages are split into smaller packets.

Store-and-Forward Mechanism

Packets can be stored temporarily before forwarding.

Shared Network Resources

Bandwidth is shared among multiple users.

Dynamic Communication

Packets may take different paths to reach the destination.

Advantages of Packet Switching

Efficient Utilization

Bandwidth is used only when data is transmitted.

Better Resource Sharing

Multiple users can share the same communication line.

Suitable for Computer Networks

Efficient for bursty data transmission.

Disadvantages of Packet Switching

Delay

Packets may wait in queues during congestion.

Variable Transmission Time

Packets may arrive at different times.

Complex Processing

Routers need memory and processing capability.

Example 

Suppose:

  • The main communication line has only twice the capacity of a data line
  • More packets arrive than the line can handle

Then:

  • Routers store packets in queues
  • Packets are forwarded one by one

This improves efficiency but introduces delay.

Key Difference

Circuit switching reserves a dedicated communication path, while packet switching divides data into packets and shares network resources dynamically.

Summary

A switched network uses switches to forward data between communication links. In a circuit-switched network, a dedicated path is reserved for communication, whereas in a packet-switched network, data is divided into packets and transmitted efficiently through shared network resources. Modern computer networks primarily use packet switching because of its better efficiency and flexibility.

Comments

Post a Comment

Popular posts from this blog

Computer Networks PCCST501 Semester 5 KTU CS 2024 Scheme - Dr Binu V P

About Me  - Dr Binu  V P Syllabus Module I Overview of the Computer Network and Internet Introduction to Computer Networks LAN ( Local Area Network ) WAN ( Wide Area Network) Comparison LAN and WAN Introduction to Internetwork Switched Network ( Circuit Switched and Packet Switched Network ) Comparison between Circuit Switching and Packet Switching Introduction to the Internet Brief History of the Internet Protocol Layering Introdcution to Protocol Layering TCP/IP Protocol Suite Functions of Each Layer in the TCP/IP Protocol Suite Encapsulation and Decapsulation in Protocol Layering Addressing in Protocol Layering Multiplexing and Demultiplexing in Protocol Layering ISO and the OSI Model Detailed Comparison of TCP/IP and OSI Model Application Layer Introduction to the Application Layer and Application Layer Paradigms Client–Server Communication Using Socket Client–Server Applications World Wide Web and HTTP FTP Electronic Mail DNS Peer-to-Peer Network  BitTorrent
Read more

Introduction to Computer Networks

  Introduction to Computer Networks What is a Computer Network? A computer network is a collection of interconnected devices that can communicate and share data with each other. These devices may include: Desktop computers Laptops Smartphones Servers Printers Routers Switches The connection between devices can be established using: Wired media → cables such as Ethernet or fiber optics Wireless media → Wi-Fi, Bluetooth, cellular communication, etc. Simple Definition A computer network is the interconnection of devices capable of exchanging information. Why Do We Need Computer Networks? Computer networks are used to: Share Resources Printers Files Internet connection Enable Communication Email Video conferencing Messaging Share Data Databases Cloud storage Multimedia content Improve Reliability and Efficiency Backup systems Distributed processing Example of a Small Network When two computers at home a...
Read more

Introduction to Local Area Network (LAN)

Image
  Introduction to Local Area Network (LAN) What is a LAN? A Local Area Network (LAN) is a network that connects devices within a limited geographical area such as: A home An office A building A school campus A LAN is usually privately owned and managed by an individual or organization. Definition A LAN is a network that interconnects hosts in a single office, building, or campus to enable communication and resource sharing. Characteristics of a LAN 1. Limited Geographical Area A LAN covers a small area compared to larger networks like WANs. Examples: Computer lab in a college Office network in a company Home Wi-Fi network 2. High-Speed Communication Since devices are located close to each other, LANs provide: Faster data transfer Lower delay Efficient communication 3. Private Ownership LANs are generally owned and maintained by: Schools Companies Universities Home users 4. Resource Sharing LANs allow multiple users to shar...
Read more