What is the difference between circuit-switched and packet-switched networks?
Both circuit switching and packet switching are methods of transferring data between two nodes in a network.
In a circuit-switched network, when two nodes need to communicate, a direct and continuous connection is established between them. It carries only the one conversation, for as long as it lasts.
For example, in the old, analog phone system, a strand of copper connected a telephone to a phone line to a switching facility. A physical link would then be made to a line to another switching station. And, from there, it would go through a strand of copper all the way to the other phone.
On a packet-switched network, data is divided into chunks, or packets. The packets have headers attached to them to identify them -- e.g., by source, destination and sequence number -- and are intermingled with the packets of other conversations on a shared network.
In a typical computer data network, computers send packets to a switch, which combines them with packets from many other computers. The combined stream may go to another switch -- an aggregation switch -- bringing together traffic from many switches or to a router that will send them on their way across the internet to other networks. Only the first connection, from computer to switch, is dedicated; all the rest are shared.
Comparing circuit switching and packet switching
There are some key differences between the two models, as illustrated in this chart:
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