What is It?
Implementation
Glossary

What is It? VoIP is the transmission of voice over the Internet and data networks. VoIP differs from traditional telephone networks in that it sends a digitized version of the callers voice over a data or IP (Internet Protocol) network rather than over a traditional circuit switched network.

By converging voice and data communications over a single IP infrastructure rather than maintaining one telephone and one data network, businesses and service providers can achieve costs savings through reduced maintenance costs and capital expenditures. For end-users, VoIP promises to transform current telecommunications by reducing long distance costs and by providing better service as well as added features through integration of phone, fax, and PC.

If you regularly make long-distance phone calls, chances are you've already enjoyed the advantages of Voice-over IP (VoIP) without even knowing it. While you probably have heard of VoIP, what you may not know is that many traditional telephone companies are already using it in the connections between their regional offices.

Implementing Convergence To provide an interface with Public Switched Telephone Network (PSTN) as well as to attempt to match the "five nines" quality, a significant amount of work has gone into developing and refining VoIP technology and has resulted in several key pieces of equipment:

            Softswitch provides call control / signaling and:
                 Converts telephone numbers to IP addresses
                 Signals for call set-up and tear down
                 Billing and accounting
                 Security
                 Call routing
                 Enhanced services that are currently provided by PBXs/trunks such
                    as call forwarding, caller ID, and sometimes voice mail, etc.
            Digital Gateway - translates between packet and telephony media
                    streams, bridging between IP networks and PSTN.
            Integrated Access Device (IAD) - enables integration of voice, data
                    and Internet and associated next-gen managed services, like VoIP,
                    over a single WAN network connection. It can also serve as an
                    analog gateway bridging between an IP network and a PBX or PSTN.