The Idea of Packet Switching

While a caller is talking over a phone the called party is listening at the other end that means half of the connection is in use at a given time. Thus, it is not necessary to maintain 128 Kbps connection during a call like circuit switched based PSTN does, it can be cut down to 64 kbps for the data transfer efficiency.

Beside, while neither party is talking there is no need for the voice or data to transfer (While both parties may sometimes speak at the same time, there are times when both parties are silent). If we remove those silent pauses, the size of total transferred data in a typical 5 minutes conversation would be even smaller.

So, instead of sending both silent and noisy data, we can send only noisy bytes and it will not affect the understanding of conversation in both ends. This concept is the basic foundation of packet switching in digital telecommunications.

Packet switching technology chops down digital voice data into small packets or chunks and then opens a brief connection between two callers to send just the noisy packets. The whole process is performed at such a high speed that there occurs very negligible interruption in phone conversations.

In case of billing, cellular communication or circuit switching impose fee per time unit of connection time between callers, even when no data is transferred, while packet switching is characterized by a fee per unit of data (such as 5 kilobytes) usage.

This cost effective packet switching has created a new era of telecommunication which is Voice over Internet Protocol (VOIP), allows you making local and international calls in very cheap rate compare to PSTN.