Circuit vs Packet Switched Networks – Packets are the Future

Having studied data network and telecommunications concepts and principles at university, I know the difference between circuit and packet switched networks but I suspect that the regular person on the street does not have the same level of knowledge or awareness. As such, I thought I would flesh this out a bit so that people would have a basic understanding of these concepts.

To put it simply, telephones delivered over copper to a Telstra exchange are examples of circuit switched networks (i.e. there is a dedicated line from your premises back to the exchange for the primary purpose of making and receiving phone calls). Putting aside digital wizardry at the exchange that handles call waiting and conferencing, the circuit cannot be used to make or receive other calls at the same time.

Packet switched networks are a different beast. A typical Internet connection is an example of a packet switched network connection whereby one pipe can be use simultaneously for many different things and makes use of packets (small chunks of data) to send and receive data. The packets are then routed between the origin and destination and the reconstructed at the other end in the same order. In this fashion, packet switching can emulate circuit switching networks without the drawback of allowing a single use of the pipe at any one time. Of course, slower connections are less capable of this emulation due to potential lag and can be easily overwhelmed. Broadband speeds help alleviate this problem, especially when it comes to the delivery of services such as VoIP (Voice over Internet Protocol).

So is this of any significance? I guess the answer is “it depends”.

The NBN will essentially provide a single packet switched connection into a premises that can fulfil the requirements for telephony, television (courtesy of IPTV) and data over fibre and you would plug in various devices (such as set top boxes, VoIP telephones, computers, etc) to make use of that connection. This may not be such a foreign concept for some people given that we have had dialup and ADSL modems that plug into telephone lines and subscription television and cable modems that plug into the coaxial socket on the wall.

Certainly, packet switched networks are the way of the future and with continually increasing bandwidth it makes sense to move away from dedicated circuits. Of course, packet switched connections that have a sole purpose (such as inter-office VPNs) will have a place.

So if you didn’t know about the above, I hope this has given you a very general understanding of the difference between these sorts of networks

Leave a Reply

Your email address will not be published.