VOiP – Voice over Internet Protocol

Written words often betray emotions. What was intended is often mistaken for something drastically obtuse. Voice conversations are different, unless the emotions and expressions betray each other of course. Nevertheless, phone calls have always been the lifeline of most people from all occupations. They are much faster than any inland mail and give a real sense of interpersonal conversation; distances seem to reduce to zero. Despite the advances of the internet into the life of a common man, phones still hold great importance. Now what if internet, living up to its reputation of being adaptable and innovative offered phone calls and that too at rates much lower than any PSTN service provider can offer? It did, and the offering was soon a phenomenon. Voice over Internet Protocol or VoIP as it is popularly known.

What is VoIP?

VoIP is a whole gamut of technologies, protocols, techniques and methodologies applied over an IP network to facilitate voice and multimedia traffic flow. It is more of a generic term, which can mean a hobbyist project on a P2P basis, or a full-fledged PSTN  replacement. It involves a sequence of well laid out steps like signaling channel and media channel set up, digitization, encoding, compression, packetization and hop-by-hop transmission over packet based IP networks as independent entities before reaching the destination.


Before we get to know how VoIP works, it would be imperative to know about two key technologies that made it possible in the first place. These technologies were nothing short of phenomenon when they were invented. The first phenomenon was the ‘Telephone’, back in 1870’s. Invented by Graham Bell and Elisha Gray. The first telephone exchange came up in 1878. Almon Strowger improved upon the switching technology and gave  the electro-mechanical stronger exchange that bore the yoke of telecom switching for more than 100 years. A paper titled ‘A Mathematical Theory of Communication’ by Dr. Claude Shannon in 1943 introduced the concept of conveying information using binary codes. This helped AT&T create ‘Touch Tone’ dialing in 1963 which ushered a new era of digital switching. The second phenomenon was the ‘Internet’, which started in around 1968 with ARPANET.

In the 70’s, time shared computer networks evolved and companies owning these networks started to rent them out during evenings and weekends when the company offices were closed. Certain online service companies like Prodigy and AOL evolved from this model and offered premium services like email_ through dial up by 1978. Tim Berners Lee and his group at CERN laidthefoundationsofthe ‘www’ with ‘http’, ‘URL’ and ‘HTML’. Earlier Dr. Vincent Cerf had invented the TCP/IP, which still holds prominence in packet based networks. Then in 1995 came the first VoIP product into the market, ‘Internet Phone’. A small company named Vocaltec Inc. in Israel invented it. It was a softphone, an application software that offered PC to PC calls. By 1998, PC to Phone and Phone to Phone VoIP had come into the market. The calls were offered for free, but the dialer had to listen to advertisements before the call was processed. A few IP switch manufacturers included VoIP switching capabilities in their equipment by 1998. By 2003, VoIP calls comprised of25% ofall calls. VoIP as we know of today, has evolved into a much more mature technology.

Flavours offered for VoIP service:

IP Phones: It is used in enterprises and institutions as Private Branch Exchanges as a suitable replacement for EPABX systems. It still forms the least obvious form of VoIP technology.

Software VoIP: Popular software like Skype forms this segment. These have been extensively used in the past global recession to curtail call costs. These can further be of three types: Web based service, instant voice and video messenger clients and web conferencing suites.

Analog Telephone Adapter: It is used in between the customer premises equipment and the network to add the IP network functionality to Analog phones.

Article Credit:  Shubhranshu (ETC, CVRCE)


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