There are two ways of transferring data over networks:

(i) circuit switching (ii) packet switching

Both have their pros / cons, or expenses and costs.

Let us use an analogy to explain the concept.

Packet Switching

Imagine you are driving in LA, or Bangalore: driving in those cities is a nightmare. Why? Congestion. Unfortunately, you’ll often find yourself stuck behind other cars, in a queue. A car may have to wait when it approaches a freeway / causeway, if there are other cars in front of it.

This example is analogous to circuit switching:

• the car is analogous to a packet.
• roads are analogous to the links in a network.
• traffic lights are analogous to: switches.

Similarly, a packet may have to wait in the output queue of a switch, if there are other packets in front of it. Necessarily, if the roads are congested, packets will have to wait much longer.

The important point to note: just as roads are shared amongst cars, so too are lines of transmission shared amongst packets.

Circuit Switching

This is analogous to having your own private road, for yourself, and no one else.

This is expensive, but it will also be quick.

The Internet: Uses Packet Switching

Everyone travels on the same road. Takes forever. If you’re in a “lucky” country like Australia, where Telecommunications networks are owned and managed by the government - well things are going to be very, very slow. The communications infrastructure is “third world”. Actually, the communications infrastructure in places like India is an order of magnitude better / cheaper and faster than it is in Melbourne.