Comparing the two fundamental data switching techniques.
Switching is the process of forwarding data from an input port to an output port on a network node. There are two primary methods for this: circuit switching and packet switching. Circuit switching is the older method, famously used by the public switched telephone network (PSTN). In this approach, a dedicated, physical end-to-end path, or 'circuit,' is established between the two communicating parties before any data is sent. This connection is reserved for the entire duration of the session, whether data is being transmitted or not. This guarantees a constant data rate and no delay variation (jitter), which is excellent for real-time voice calls. However, it's inefficient because the channel capacity is wasted during periods of silence. Packet switching is the method used by the internet. Here, data is broken down into small, fixed or variable-sized blocks called packets. Each packet contains a header with the source and destination address. These packets are then sent into the network individually. They travel from router to router, and each router makes an independent decision on where to forward the packet next. The packets may take different paths and arrive out of order at the destination, where they are reassembled. This approach allows many users to share the same network resources dynamically. It's highly efficient and robust, as packets can be routed around failed links. However, it doesn't offer the same performance guarantees as circuit switching, and packets can experience variable delays and be lost due to congestion.