Packet Switching: Advantages and Disadvantages

This page covers the advantages and disadvantages of Packet Switching (PS). It highlights the benefits and drawbacks of this technology, and provides links to understand the difference between Packet Switching and Circuit Switching.

What is Packet Switching?

Introduction

Unlike Circuit Switching (CS) networks, Packet Switching doesn’t require an initial connection establishment. The connection/channel is available for multiple users. However, as capacity increases or the number of users grows, network congestion can occur.

Packet switched networks are primarily used for data and voice applications that don’t demand real-time performance.

In packet switching, the sending device (e.g., station or IP device) divides a long message into smaller packets. It then adds headers according to predefined TCP/IP stack formats. These headers contain crucial information, including the source address, destination address, packet length, port number, protocol field, and checksum.

Packets are transmitted sequentially and reassembled at the receiver using sequence numbers.

Packet switching handles packets in two primary ways:

• Datagram: Each packet is treated independently. Packets can take any route between the source and destination. They might arrive out of order or even fail to reach the destination.

• Virtual Circuit: A pre-planned route is established before packet transmission begins. “Call request” and “call accept” messages are used as a handshake mechanism. In this approach, each packet contains a Virtual Circuit Identifier (VCI) instead of the destination IP address. Routing decisions are only made once for all packets within the virtual circuit, simplifying the process.

Benefits or Advantages of Packet Switching

Here are the benefits and advantages of Packet Switching:

• Memory Efficiency: Because packets have a maximum length, they can be stored in the main memory rather than the disk, reducing access delay. Fixed packet sizes also improve delay characteristics, as long messages are not present in the queue.

• Cost-Effective: Switching devices don’t need massive secondary storage, resulting in lower costs. Packet switching is a highly cost-effective technique overall.

• Reliability: Packets can be rerouted in case of problems (e.g., busy or disabled links), ensuring more reliable communication.

• Efficient Data Transmission: It’s more efficient for data transmission because it doesn’t require a dedicated path to be established between sender and receiver; data is transmitted immediately.

• Bandwidth Sharing: Multiple users can share the same channel simultaneously, making efficient use of available bandwidth.

• Modern Applications: With improved protocols, packet switching is widely used for video and voice calls through applications like WhatsApp, Skype, and Google Talk.

• Widespread Availability: Due to competition among telecom carriers and the availability of modern wireless standards like LTE and LTE-Advanced, packet switching is extensively used by internet users.

Drawbacks or Disadvantages of Packet Switching

Here are the disadvantages of Packet Switching:

• Not Suitable for Real-Time Applications: Packet switching networks are not suitable for applications requiring very little delay and a high Quality of Service (QoS), such as reliable voice calls.

• Protocol Complexity: The protocols used in packet switching are complex and require significant initial implementation costs.

• Potential for Packet Loss: If the network is overloaded, packets can be delayed, discarded, or dropped, leading to retransmission by the sender. This can result in the loss of critical information if errors are not recovered.

• Security Concerns: It’s not secure without the use of security protocols (e.g., IPsec) during packet transmission.