A number of protocols were developed in the 1990s that made the possibility of VoIP a reality. The two most prominent of these Internet protocols are RTP (Real-Time Transport Protocol) and its companion RTCP (Real-Time Transport Control Protocol. The biggest challenge facing Voice over IP was that of latency in the network, because VoIP is a ‘Real Time’ protocol, it can only suffer minimal latency or delay before the quality of the voice media stream deteriorates to the point where the user finds it difficult to hold a conversation. As well as end-to-end latency, packet jitter can also render a VoIP call unworkable.
Some people refer to VoIP as Internet Telephony, but this is specifically the use of the Internet itself for the passage of telephone calls. Business VoIP utilises private, Quality of Service (QoS) based networks.
VoIP has many advantages or traditional circuit switched telecommunications networks, least of all the fact that it can share the same infrastructure as data traffic. Many service providers and telecommunications companies are turning to Voice over IP, and in some cases offering a VoIP service free when signing up to other services such as Broadband, IPTV and VOD (Video on demand). Traditional telecommunications companies make more money from broadband and other services these days, as the public require fast access to many different Internet services. Consequently, there has been a sharp drop off in the number of landline telephones being commissioned. Some people no longer have a landline telephone, as they prefer to keep in touch via a mobile device.
VoIP is now a maturing technology and here at NSTUK we run a number of VoIP training courses, including Hands-On versions designed to give students a grounding in the family of protocols that make up VoIP.