VoIP Competition: FYI - NORTEL
Voice Over IP
Raising the quality benchmark
Anyone who has ever experienced voice over IP on today's public Internet is well aware of the limitations of unmanaged public IP networks. Calls can be impacted by delays in the voice path, which cause echo impairment and can interfere with the mechanics of conversational "turn-taking." And network congestion can prevent packets from reaching their destination in time to be decoded, causing the signal to be distorted or even muted.
By contrast, voice-over-IP implementations over managed IP networks (i.e. intranets) can produce audio quality comparable to today's wireline networks. Nortel Networks offers voice-over-IP products and network solutions today that deliver this quality.
Looking ahead, Nortel Networks research indicates that mission-critical networks optimized for IP are capable of delivering superior-quality conventional voice through easily accessible, high-fidelity, wideband audio services. "When we apply our expertise to the IP domain, voice communications can actually sound better than any audio transmission we know today", says David Cuddy, director, network edge technologies.
Carrying forward the corporation's century-long heritage in end-to-end voice networking solutions, Nortel Networks engineers have designed a wideband voice-over-IP device prototype that incorporates the latest in audio, acoustic, and digital signal processing technologies.
Wideband audio is difficult to achieve with today's circuit-switched networks, which are engineered for 64-kilobit-per-second (kbps) signals with a frequency bandwidth of less than 3 kilohertz (kHz). By contrast, the bit rate and frequency range of webtone networks - and the kinds of voice services they can carry - are limited only by the capabilities of the devices and transducers at the communications endpoints.
Nortel Networks' wideband voice-over-IP device prototype leverages this inherent advantage by delivering two-way voice communications with a frequency range of 7 kHz - more than two octaves better than conventional circuit-switched voice. The quality of this audio experience greatly enhances many existing Web services - such as radio broadcasts and interactive video games. It also opens the door to interactive single- or multimedia Web applications with rich, resonant, "virtual presence" audio quality.
Development of these technologies is being supported by voice-over-IP performance tests conducted by Nortel Networks' world-class subjective assessment laboratory. Using the industry's most important performance yardstick - the preferences of real-world end-users - this lab is analyzing and quantifying the performance of commercially available and experimental voice codecs in a variety of voice-over-IP network configurations. The results of these evaluations are guiding engineers to deliver superior end-to-end voice quality solutions over evolving IP networks.
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