What is VoIP and how does it work?

Voice over Internet Protocol may sound like a new innovation as it has only become popular in homes over the last five-ten years; however, it actually dates back to the 1970s when it was used as an experiment by the US department of defence.

Traditional phone networks use circuit switching – that is when a call is made, circuits are switched in the intervening exchange creating a connection between the caller and the person being called.

By contrast, VoIP employs packet switching – which has typically been used by data networks connecting computers. Within this network, data is divided into small packets which are given identifying information and are then transported across the network. At the end of the line, they are reassembled to provide the information to the receiver.

This process is now applied to voice calls through VoIP. In the past packet switching was rarely used for voice calls because the reassembling of information would seriously deteriorate the quality of the call. However, thanks to improved systems which now give priority to voice calls over data, the quality of VoIP is now arguably on the same level as a regular phone call.

With the emergence of the internet and its incredible boom in popularity, particularly in the late 1990s, more companies began to explore VoIP as a serious alternative to regular landline calls.

There are now a host of companies that offer VoIP services in the UK. These services take a variety of forms:

• PC to PC – This form of VoIP takes place with a headset and is usually used on an instant messenger service. A common example is Skype.
• PC to telephone network – This is when only the caller uses a headset. A common example is CallServe.
• Telephone network to telephone network – When the caller uses an adaptor on the telephone. A common example is BT Broadband Voice.
• IP phone to telephone network – This is when the phone itself is IP enabled and so there is no need for an adaptor. A common example is Vonage.

It has been suggested that Voice over Internet Protocol (VoIP) could be the long term successor to regular phone calls. So is VoIP as good as it sounds? Just what are the benefits of this new service and are there any disadvantages?