Difference between a Circuit Switching and Packet Switching


Circuit switching and packet switching are the connection types that we use when sending data from one place to other.

Circuit switching

With circuit switching, we are building a connection between locations so that we can send data over those lines. The circuit is established between endpoints before data passes.

Things like phone calls use circuit switching, we are picking up the phone, we are dialing the number, we are connecting to that site, and we are sending data, we are not able to talk to anyone else or make any other phone calls until we hang up with that connection and then we establish a new circuit to someone else. Nobody else can use the circuit when it’s idle.

Insufficient use of resources, an important consideration with circuit switching technologies, is once you build that circuit, it’s in place until you tear it down, even if you’re not sending data over that connection that circuit is still in place, and those two sides are connected.

If you’re sending data during the day and nothing goes across the link at night, there is a certain waste of resources, and that is a challenge with circuit switching. But the connection is always there and it’s yours, you can use the connection at any time you like, and no one else can take advantage of using it.

Common circuit switching networks are things like the telephone that we use POST- plain old telephone network or PSTNpublic switching telephone network lines those are effecting the same thing. So T1, E1, T3 or E3 type connection is certainly going to be used as a circuit switch where we build connection and is always going to be there.

ISDN (Integrated Services Digital Network) is a bit of an upgrade from the telephone. But it still dials a phone number and creates a circuit. And that is what you’re going to send data over the ISDN network.


Packet Switching

Packet switching is how we think of networking today. We take our data, we put it into a wireless network or a wired network and we send traffic on its way and it finds its destination. It might be data or video or voice, but doesn’t matter, and finding it the way and switching based on what is in the packet.

The media is usually shared, someone can use it, even when you don’t. We have many people sharing a connection to the internet (maybe the internet links themselves are shared between the locations). That way we not using the connection, someone else could certainly be using exactly that connection

In this regard, the internet service providers generally charge us based on how much bandwidth we are going to use.

One connection may have more bandwidth than another because you paid more money, and those who pay less money in a month will have less bandwidth.


Common packet switching technology is;

  1. Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH)
  2. Asynchronous Transfer Mode (ATM)
  3. Digital Subscriber Line (DSL)
  4. Satellite connections
  5. Multiprotocol Label Switch (MPLS)
  6. Cable modem
  7. Frame relay
  8. Wireless

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