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For more than 80 years, the Public Switched Telephone Network (PSTN) has been the most reliable medium for connecting phone calls. But advances in technology and deregulation of the telecommunications industry have taken their toll on this copper-wire legacy system. The days of dedicated circuits designed specifically to carry voice traffic are limited.
Internet Protocol (IP) has made as great an impact on the telecommunications market as it has in the data world. With IP-based voice transmission, the medium is irrelevant. At the most simplistic level, voice is now data, so it can be transmitted over any network, including cable, fiber, wireless and copper. The future of voice technology revolves around IP and its inherent reliability and flexibility.
But to reach the future, we have to get through the present. With billions of dollars invested in copper-based systems, carriers aren't going to just abandon the current PSTN. Additionally, cable companies need to upgrade their existing Hybrid Fiber Coax (HFC) networks to accommodate voice. The original cable networks were designed for video, which is a one-way transmission. Voice is a two-way communications transmission.
The success of IP-based voice transmission is dependent on a variety of factors, each of which is unique to the industry segments within the newly defined telecommunications industry. In the telco sector, carriers need to agree on an open, standards-based protocol to serve as the foundation for all future development.
Currently, Media Gateway Control Protocol (MGCP) and Session Initiation Protocol (SIP) are the two carrier-class interoperability protocols with the most promise of becoming industry standards. The inherent simplicity of these protocols makes them easy to deploy in networks, and numerous industry vendors already are implementing MGCP and SIP into Voice-over-Internet Protocol (VoIP) solutions.
Wireless, on the other hand, is developing 3rd generation (3G) initiatives and moving from Wireless Application Protocol (WAP) to the Global System for Mobile Communications, referred to as GSM. GSM is seen as the international standard of choice between Japan and Europe, which are leaders on the 3G-adoption curve. Ultimately, proponents of 3G are pushing for migration to the Universal Mobile Telecommunications System (UMTS) that can provide access to voice and data at 144 kbps while in a vehicle, 384 kbps while walking and 2 mbps fixed/local access.
Unlike its telco and wireless counterparts, the cable industry already has agreed on Data Over Cable Service Interface Specification (DOCSIS) as the standard-based protocol upon which all future technology will be based. DOCSIS v1.1 enables cable operators to expand their service offerings on existing HFC. With a little help from a Cable Modem Termination System (CMTS), video, voice and data are transmitted across the HFC network and directed to the television and cable modem. The cable modem directs the Internet traffic to a personal computer and the voice traffic to the phone.
With open, standards-based protocols in place, the migration period to IP telephony will quicken. VoIP equipment manufacturers already are claiming the same 99.999 percent reliability of the PSTN, so the real issue is bridging the legacy systems to new broadband Internet solutions.
The Nuera Solution
Nuera Communications, Inc. has developed a flexible, cost-efficient way for communication service providers to integrate IP telephony equipment into current PSTN, cable and wireless infrastructures. In fact, the company's Open, Reliable Communications Architecture product family allows the migration of voice capabilities to data networks and the Internet by acting as a translator among protocols. Protocols supported by various Nuera products include SS7, SIP, MGCP, H.323, DOCSIS, 3G and others.
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