IP, the packet technology used on the Internet, has proven its ability to efficiently integrate voice traffic into the flow of data on IP networks, enabling voice and data services to be delivered to users from a single multi service network. Voice over IP supports two-way transmission of voice traffic over a packet-switched IP network. This network could be a public carrier network, the Internet, or a private enterprise intranet. The term "Internet telephony" generally refers to Voice over IP services transported over a public Internet backbone, but the terms are often used interchangeably.

VoIP's Evolution

The first widely used VoIP application appeared in the mid-1990s, with services that enabled Internet users to make free voice calls between specially equipped PCs, or between a regular phone and a specially equipped PC. Even though quality was often erratic, users found this early VoIP technology a great way to save toll charges on long-distance and international calls. Circuit-switched networks were designed to carry voice traffic over a reserved channel for each conversation (even when no one's talking). Over the last two decades, both service providers and enterprises have been using packet technologies (such as frame relay, ATM, and IP) to transport data. In a packet network, packet switching interleaves bits and bytes of traffic from many users on shared facilities, using the network's available bandwidth far more efficiently.

Because these two types of networks have been used for a single service only, service providers and enterprises have had to invest in two separate networks if they wanted to transport both voice and data traffic. Building, managing, and maintaining these "overlay" networks has proven to be very expensive. IP, the packet technology used on the Internet, has proven its ability to efficiently integrate voice traffic into the flow of data on IP networks, enabling voice and data services to be delivered to users from a single multi service network.

Benefits of VoIP

Voice quality on managed IP networks (controlled Internet backbones or an enterprise's private network) can match the public voice network. And IP networks are far more bandwidth efficient. Newer voice codecs consume only 8 Kbps to produce acceptable voice quality, compared to 64 Kbps with traditional networks. Combined voice and data communications over a single integrated platform built on packet technology offer the performance characteristics that voice service requires and provides:

• Sustainable cost reduction—Lowers capital and operating costs by converging separate voice and data networks into a single, multi service network. Increased revenues—Raises the value of voice service, with new applications such as video calling, unified messaging, and Web-enabled multimedia call centers. With multiple services available on a single customer link, providers have lots of opportunities to bundle, cross-sell, and upsell services.
• Enhanced productivity—New applications such as collaboration and unified messaging enable enterprise employees, wherever they happen to be, to team more effectively and be more productive.

With its growing popularity and eventual displacement of traditional telephony technologies, it is clear that VoIP will be ubiquitous as we move forward. Given its advantages and promises for an improved communications environment, VoIP, as any new technology prompts many questions to the uneducated. Questions centered around security, provisioning, performance are common when considering deploying VoIP in your enterprise, small business or technical lab. You should be armed with the answers to key questions such as: how to secure my VoIP call server? What vendor is best for a small business? Which vendor's signaling solution is more secure? What is the best bang-for-buck voicemail solution? Should I use traditional ("hard") phones of software phones?

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