Difference between Circuit Switching and Packet Switching

Switching is a method to forward data packets coming in from the sender to the receiver at the destination address. Circuit switching and packet switching are the two most popular methods of switching. In circuit switching, data is transferred on a dedicated channel that is to be established between the sender and the receiver using a dedicated point-to-point connection. In packet switching, data is split into small units called packets with each packet being associated with a header containing signaling information about the source and destination nodes. The packets are transmitted independently and are processed at all intermediate nodes before reaching their destination. At the destination, the data packets are extracted and reassembled to get the original message. Let’s study the difference between the two in detail.

What is Circuit Switching?

Circuit switching is one of the switching technologies used to send messages from one point to another using a dedicated point-to-point link throughout the session. They are mainly used in PSTN (Public Switched Telephone Network) where the caller and receiver exchange information on a dedicated channel using an end-to-end link. This is a connection oriented channel which is established between the sender and the receiver using a dedicated signaling protocol. When either of them disconnects the call, the circuit breaks thereby terminating the session. In simple terms, the sender establishes a physical connection with the receiver along a dedicated circuit to send data transmissions and when the data transfer completes, the circuit is released. All data is transmitted along the same circuit throughout the session.

What is Packet Switching?

Packet switching makes the most out of the network bandwidth by breaking the message into small units called data packets which seek the most efficient routing path to reach its destination. Each data packet is assigned a header containing signaling information including the sender and receiver address, and then transmitted individually through the network. Each data packet may take a different route as addressed by its associated header. The data is processed at all intermediate nodes located at various points before reaching its destination where all the packets are reassembled and recompiled into the original message. It’s a more robust and efficient method to transmit data that can withstand some delays during the session. It’s mainly used for data and voice communication.

Difference between Circuit Switching and Packet Switching

1. Definition of Circuit Switching and Packet Switching

   – Circuit switching is a type of networking protocol in which a dedicated channel is established between two end points in a network for the duration of a transmission. Data transfer takes place after the circuit is established. Packet switching, on the other hand, is connectionless which means the data is transmitted into small units called packets and a dynamic route is established for each packet.

2. Approach in Circuit Switching and Packet Switching 

   – In circuit switching, an end-to-end circuit path is established between source and destination using a dedicated signalling protocol. It is connection oriented, unlike connectionless packet switched networks, which don’t follow an end-to-end approach. In fact, each packet carries source and destination addresses in the header.

3. Flexibility in Circuit Switching and Packet Switching

   – In packet switching, data communication is split into small packets with each packet carrying routing information and following different path of transmission to reach their destination. Circuit switching, on the other hand, is not flexible as a dedicated path is established which doesn’t change throughout the transmission.

4. Routing Path of Circuit Switching and Packet Switching

   – In circuit switched networks, all data passes through the same circuit and each data unit has sole access to a circuit and the entire routing path is provided at the source. Whereas in packet switched networks, each data packet contains entire routing path and is transmitted individually.

5. Data Processing in Circuit Switching and Packet Switching

   – In circuit switching, the transmission path is decided before the data processing begins and the system decides on which path to follow. In packet switching, data is split into small packets – each with an associated header – that are routed from source to destination and are processed at all intermediate nodes.

6. Application of Circuit Switching and Packet Switching

   – Packet switching is the more efficient method when it comes to data transmission, whereas circuit switching is a much better alternative for voice transmission. While the former is implemented at physical layer, the latter is implemented at the network layer.

Circuit Switching vs. Packet Switching: Comparison Chart

Summary of Circuit Switching and Packet Switching

While both packet switching and circuit switching are the two most common methods of transferring data between two communication devices, both follow a different approach for sending messages from one point to another. Circuit switching utilises a connection oriented approach in which a network link is dedicated to one connection at a time and no other user is allowed to use that circuit. On the contrary, packet switching divides the data to be transmitted into small units called packets with no end to end reservation of network links. They both use different technologies to transmit data from one point to another thereby connecting multiple devices with each other. Each has its fair share of pros and cons depending on what you’re trying to do.

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