VoIP (Voice over Internet Protocol) What is it ?
A category of hardware and software that enables people to make telephone calls via the Internet. Voice signals are converted to packets of data, which are transmitted on shared, public lines, hence avoiding the tolls of the traditional, public-switched telephone network (PSTN).
VoIP applications can generally be used with a simple microphone and computer speakers, but IP telephones or VoIP boxes can also be used, providing an experience identical to normal telephoning. In the past year, the quality and reliability of VoIP technology has improved to the point that vast numbers of users have abandoned their standard telephone contracts entirely, in favor of VoIP.
The quest for better telephony
VoIP first appeared in 1995 when Pentium processors and sound cards were introduced in the home PC market. Affordable processing power made it possible to hold voice conversations across the Internet using
PC-based software. Users had to enter a chat room before they could talk. Then came direct PC-to-phone or phone-to-phone communication with no chat room. VoIP has come a long way since then.
VoIP (voice over IP) technology is a rapidly expanding field. More and more VoIP components are being developed, while existing VoIP technology is being deployed at a rapid and still increasing pace.
Network and service providers see VoIP technology as a means of reducing their cost of offering existing voice-based services and new multimedia services. Service providers also view VoIP infrastructure as an economical base on which to build new revenue-generating services. As deployment of VoIP technology becomes widespread and part of a shared competitive landscape, this second goal will become more important, with service providers working to increase their market bases.
This is only the begining
VoIP is a disruptive technology that is causing significant change in the way voice communication services are delivered. It is providing future roadmaps for telecom networks. This is only the beginning of a more significant move to convergence. As the world moves to a common IP-based data network as backbone, VoIP is only one of the realtime services offered on such networks, along with many data services. The same network will also support video services from videoconferencing to entertainment video.
More important, these services allow convergence at the control and user levels. A user can initiate a call or TV program from the Web and then send a video from a camera phone to the user’s home Web site. Common Web-based services can be used for provisioning the user’s personal choices. Clearly, this is only the beginning of exciting services offered by full multimedia on IP.
An important architectural change is that all application servers will move out of specific networks and become more access-independent. Networks will become multiservice platforms. To do this effectively, networks have to provide flexible QoS mechanisms and the ability to create virtual networks to match the services being deployed. This is where many of VoIP challenges remain to be solved. Specifically, we still need ways to specify network requirements of a particular application (e.g., multiparty audio-conferencing) and we need to be able to map that to the multiservice network. Finally, we need to be able to provision such services and monitor their execution to guarantee delivery.
Last, but not least, is the challenge of integrating the ever-smarter endpoint and endpoint-based applications with the network-centric view presented earlier. Besides new service interaction issues, this raises many new concerns about ownership of the user’s data, authentication, billing for services, and responsibility for security.
VoIP is here and already leading the way not just to cheaper voice calls but also to a host of new applications. We need to focus on the challenges to enable a host of new multimedia applications.
