Voice over Internet Protocol (VoIP), the revolutionary communication technology is all set to replace the the traditional phone system in the near future.

Today, it is possible to make toll free long distance voice and fax calls over existing IP data networks. Businesses implementing own VoIP systems can save a lot on long distance calls.

VoIP converts the voice signal from telephone into digital signal that travels over the internet and then it is converted back into voice signal at the other end, thus making it possible to speak using regular phones with Internet.

At each end of a VoIP call, there is an analog soft or IP phone acting as a user interface, client software working with a codec to handle the digital to analog conversion and soft switches mapping the calls. The different pieces of hardware and software work together with various protocols.

The protocol H.323 developed by International Telecommunication Union (ITU) was widely used earlier. It was however found to be very complex and consisted of many protocols and specifications. It was not specifically tailored for VoIP.

Then came Session Initiation Protocol (SIP), specifically for VoIP application. Media Gateway Control Protocol (MGCP) is the third commonly used VoIP protocol. Now there is a proprietary peer-to-peer protocol used inSkype.

Read on to find out how SIP and Skype are driving the future of VoIP.