The State of VoIP
Just a few years ago, voice over IP (VoIP) was considered a novelty, but with annual growth rates of more than 20 percent, adoption of this service is widespread throughout the business and private sectors.
JUST A FEW YEARS AGO, VOICE OVER IP (VoIP) was considered a novelty, but with annual growth rates of more than 20 percent, adoption of this service is widespread throughout the business and private sectors. Some analysts estimate that almost 40 million people will be using some type of VoIP service by 2010. For enterprise customers, which already rely on IP communications for e-mail, messaging, and, now, videoconferencing, the shift to VoIP is a natural evolution.
However, there are some who question why it has taken so long to get to this point. One hurdle to widespread adoption was the lack of interoperability among manufacturers, which made it difficult for companies to communicate with others not using their own telephone system.
To overcome this, service providers are adopting Session Initiation Protocol (SIP) as a standard for VoIP communications, and manufacturers of VoIP products are increasingly adhering to International Telecommunication Union (ITU) standards — both narrowband codecs, such as ITU G.711, wideband codecs, such as ITU G.722, and standard codecs for voice compression, such as ITU G.722.1. “Users want choice, they don't want to be locked in, and they want network devices that are fully interoperable,” says Chalan Aras, vice president of marketing of the voice communications division at Polycom. “From a CIO perspective, suppliers are being strongly encouraged to be as open as possible and offer alternatives. SIP and standards-based systems are no longer a ‘nice-to-have,' they are the expectation.”SIP SWITCH
In the VoIP world, SIP helps to standardize everything. This IP-based technology is essential to the various components of a system — such as application servers, soft switches, and gateways — so they can all “talk” to one another.
Now some of the Internet telephony service providers are offering SIP trunking to make VoIP communications seamless from location to location. IP Private Branch Exchange (IP PBX) vendors such as Avaya, Cisco, 3Com, Nortel, and others are all standardizing on SIP moving forward, Aras notes. Several manufacturers of VoIP endpoints have adopted the ITU G.722 standard for operation.
A major advantage of VoIP telephony over standard dial-up lines is the potential for dramatically enhanced audio quality. Unlike dial-up lines, which provide only 3 kHz of bandwidth (with the bottom end limited to 300 Hz), G.722 calls have the potential for a full 7 kHz of audio bandwidth.