Voice over Internet Protocol

Voice over Internet Protocol (VoIP, IPA: /vɔɪp/) is a general term for a family of transmission technologies for delivery of voice communications over the Internet or other packet-switched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony and Internet telephony, as well as voice over broadband, broadband telephony, and broadband phone, when the network connectivity is available over broadband Internet access.

VoIP systems usually interface with the traditional public switched telephone network (PSTN) to allow for transparent phone communications worldwide.

VoIP can be a benefit for reducing communication and infrastructure costs by routing phone calls over existing data networks and avoiding duplicate network systems.

Voice-over-IP systems carry telephony speech as digital audio, typically reduced in data rate using speech data compression techniques, packetized in small units of typically tens of milliseconds of speech, and encapsulated in a packet stream over IP

History

Voice-over-Internet Protocol has been a subject of interest almost since the first computer network. By 1973, voice was being transmitted over the early Internet The technology for transmitting voice conversations over the Internet has been available to end-users since at least the early 1980s. In 1996, a shrink-wrapped software product called VocalTec Internet Phone (release 4) provided VoIP along with extra features such as voice mail and caller ID. However, it did not offer a gateway to the PSTN, so it was possible to speak only to other Vocaltec Internet Phone users.^[3] In 1997, Level 3 began development of its first softswitch (a term they invented in 1998); softswitches were designed to replace traditional hardware telephone switches by serving as gateways between telephone networks

Revenue in the total VoIP industry in the US is set to grow by 24.3% in 2008 to $3.19 billion. Subscriber growth will drive revenue in the VoIP sector, with numbers expected to rise by 21.2% in 2008 to 16.6 million

Cisco to ship Wi-Fi mobile phone in June

he phone, which will carry the model number 7920, communicates only with IEEE 802.11b technology and is designed for use within enterprises rather than totally replacing a cell phone, said Charlie Giancarlo, senior vice president and general manager of switching, voice and carrier systems. However, San Jose, California-based Cisco is in talks with cell phone makers about the possibility of adding cell phone capability to such a device, which might carry the Cisco brand.

The 7920 joins Cisco's 7960 IP (Internet Protocol) phone, which sits on a desk and plugs into a wired Ethernet network, and brings the added benefit of mobility around a building or campus that has a wireless LAN. It uses the same type of interface as the 7960, albeit with a smaller display, and lets users enjoy all the features of the company's IP PBX (private branch exchange) wherever the wireless LAN reaches. The phone will ship in June at least in the U.S. and will be available in other countries soon after, he said.

The new phone could be ideal for environments such as retail stores where employees need to move around a site during the work day, Giancarlo said. A phone that combines Wi-Fi with wide-area cell phone capability would be well suited to mobile professionals who frequently use a cell phone for business calls, he added.

No price has been set yet for the 7920, which is currently in beta testing. The example shown in a presentation Wednesday was dark gray and looked like a slightly bulky cell phone. To make the product practical, Cisco broke through a high power consumption problem that some industry observers have cited as a challenge for handheld Wi-Fi devices, Giancarlo said. The phone should deliver two hours of talk time and 24 hours of standby time on a charge, he said. It will be available with a cradle that can be used for charging and will have a jack for a headset so employees can use a single phone at work, he added.

Companies are starting to embrace IP telephony now that problems such as quality of service have been worked out, according to James Pratt, vice president of sales at Netcom Group, a value-added reseller in Grand Rapids, Michigan, who attended the conference. Customers are turning to IP telephony because it simplifies their network infrastructures and can lower costs, and a mobile IP phone would be attractive to many companies because it would let them add mobility without paying for cell phone airtime, Pratt said. On the other hand, combining Wi-Fi
and wide-area cell phone capability on a single device is still hard in North America because there are multiple cell phone technologies in use, he said.