Alexander Graham Bell’s invention – Telephone, has taken many ‘Avatars’ with time. I still remember the days when we had to depend on the operator to connect us. Then came ‘Automatic’ Exchanges using which we could dial on our own. This form of telephony (PSTN as it is called today) works on a technology called Circuit Switching. In circuit switching, a path from caller to the called party is dedicated throughout the duration of a call. With advancement in technology, sharing started happening at aggregation level. This is called ‘Multiplexing’. This brought in better efficiencies of scale and allowed Telecom companies to expand their base in terms of connections (of course, they had to add a whole lot of equipment other than the multiplexers to expand). Meanwhile data communication was born which is packet based and there is no dedicated path in it. Read more…