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VoIP, or 'Voice over Internet Protocol' refers to sending voice and fax phone calls over data networks, particularly the Internet. This technology offers cost savings by making more efficient use of the existing network. |
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IP Telephony is the technology of transmitting voice and fax over data networks using the Internet Protocol (IP). This technology offers new capabilities and enormous cost savings by taking advantage of the intelligence and more efficient use of the network. This creates the potential for new opportunities and services. |
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An VoIP Gateway allows Internet telephone calls to be sent onto the PSTN by taking voice by converting circuit-switched calls onto the packet-switched network and back again. This allows a person at a PC to call any telephone number served by the gateway. VoIP gateways take voice (or even a fax transmission) from the circuit-switched PSTN and place it on the packet-switched Internet and vice versa. The cost elements in PC-to-phone calls are the cost of connecting from the PC to the local ISP and the cost of connecting from the VoIP Gateway at the endpoint to the phone at the final destination. In most cases, the connections from the gateways to the calling party's are local phone calls. Since the charge for the long distance transmission is going out over the Internet the cost of the call is minimal. |
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The traditional telephone network often referred to as the Public Switched Telephone Network (PSTN) and uses circuit switched technology to transmit calls. A dedicated connection or circuit is created that connects two parties. When a phone is dialed there is a dedicated path created from the users phone system to the call recipient. The PSTN network provides real-time transmission with a guaranteed quality of service level ensured by a dedicated circuit shared on the telephone call. The circuit is not used efficiently because it is dedicated throughout the duration of the phone call but most conversations are largely made up of silence, so the circuit while in use is not actually transmitting anything. |
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VoIP is different from the PSTN because it does not use dedicated circuits; multiple users share networks. Information is transmitted over the network in packets and the network is often referred to as a packet-switched network. This is extremely efficient because the network is only used when it is transporting packets of information.
When using an IP network to transmit voice, issues such as the speed of the Internet connection, other traffic on the Internet, latency (the delay that takes place from the time someone speaks till the time the other person can hear them), and the delays or loss of the transmittal of packets that lowers the quality of the voice conversation need to be addressed
The billing mechanism for VoIP is based on the amount of bandwidth used or dedicated.
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It depends on two primary factors, the amount of bandwidth available and the IP Endpoint connected (whether there are additional components that are providing processing power to improve the connection).
Most people's initial introduction to PC Telephony is through dial-up Internet accounts that offer 'narrow' bandwidth. This users experience ranges of quality depending upon the amount of traffic on the net, and bandwidth limitations that can lead to packet loss, latency and jitter. This shows up as a clipped effect with gaps of speech or garbled sound.
Specially designed products with sophisticated electronic components that provide additional processing power to address these technological shortcomings can dramatically improve these problems.
All of the leading ITSP's are introducing Broadband solutions that offer bandwidth that supports high quality telephone calls. Coupled with the appropriate interface devices, these calls are indistinguishable from a traditional telephone call.
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