Describe circuit switching and packet switching. (6)

Answer 1

Circuit switching and packet switching are two fundamental techniques used for transmitting data over networks. Here’s a description of each method:

Circuit Switching

1. Dedicated Connection: In circuit switching, a dedicated communication path or circuit is established between two endpoints for the duration of the communication session. This is akin to a telephone call where a dedicated line is set up.

2. Resource Reservation: Once the connection is established, all resources (bandwidth, channels) remain reserved for that particular call, even if no data is being transmitted. This can lead to inefficiencies, especially if one party is silent for a period.

3. Consistent Quality: Circuit switching provides a constant and predictable quality of service, as the bandwidth is fixed and not shared with other users during the communication.

4. Setup Time: There is a notable setup time required to establish the connection before data transmission can begin. This can add latency to the start of communication.

5. Examples: Traditional landline telephone networks and some private branch exchange (PBX) systems use circuit switching.

6. Limitations: The main limitations of circuit switching include inefficient resource usage when connections are idle and limited scalability due to fixed bandwidth.

Packet Switching

1. Data Segmentation: In packet switching, data is divided into smaller segments called packets. Each packet is routed independently over the network.

2. No Dedicated Path: There is no need for a dedicated communication path between the sender and receiver. Each packet can take different routes to reach the destination, optimizing the use of network resources.

3. Dynamic Resource Allocation: Bandwidth is used more efficiently as multiple packets from different sources can share the same network path. If one path becomes congested, packets can be rerouted through alternative paths.

4. Variable Quality: Because packets may take different routes and arrive at different times, the quality of service can be variable, leading to issues such as latency and jitter.

5. Examples: The Internet is primarily based on packet switching, where protocols like TCP/IP manage how packets are transmitted and reassembled at their destination.

6. Advantages: Packet switching generally offers better utilization of bandwidth and greater scalability, allowing networks to handle varying loads more effectively.

In summary, the choice between circuit switching and packet switching depends on specific application needs, with circuit switching often favored for real-time voice communications and packet switching dominating data transmission, especially in modern networking environments.