INTERNET PROTOCOL (IP) TELEPHONY, or voice-over IP (VoIP), has proved to be a wise decision for many organizations. This technology crosses the boundaries of public and private networks, enterprise and residential markets, voice and data technologies, as well as local and long-distance services. The convergence of voice and data into a single, powerful network enables an organization to reduce costs, consolidate and simplify networks, as well as better serve its customers and constituents.
IP telephony is an enabler of increased productivity and customer engagement. Running on a converged, application-optimized network, IP telephony solutions now scale to 200,000 users--serving remote users, telecommuters, remote offices, contact centers and broad campuses. The Internet is used extensively for employee, partner, student, and faculty remote access and connectivity to remote facilities and small campuses while leveraging IP-VPNs (virtual private networks) for data applications. Therefore, it is very appealing to enhance the productivity of mobile users and remote office workers by supporting IP telephony.
IP telephony over wireless and soft clients on PCs and laptops give mobile users access to full multimedia capabilities from anyplace at anytime. In addition, IP telephony over wireless, combined with the plug-and-play nature of this technology, serves a major role in campus safety. It also helps to provide business continuity in the case of natural disasters or emergency situations.
An IP telephony system is a hardware and software solution made from a set of four logical functions:
1. IP telephones and PC soft clients.
2. Communications servers, a.k.a, call management servers or gatekeepers.
3. Media gateways providing flexible network access--for example, via traditional public branch exchanges (PBXs), the public switched telephone network (PSTN), the pubic wireless network and beyond.
4. Application servers-- for example, unified messaging conferencing and session initiation protocol (SIP)-enabled collaborative applications.
These functions ate distributed across an enterprise IP network, with extended reach and mobility provided over wireless LANs and the Internet.
True IP Telephony
To offer true IP telephony, providers must deliver network capabilities on three layers: hardware, enabling software and application software. Network hardware includes the call controllers, gateways, optical transmission elements and end-user equipment that physically transmit packets from one place to another. Enabling software is the core intelligence that gives users access to the network and performs basic functions such as completing a call. The enabling software types are call control, quality of service, directory services and security services. Application software includes the software modules that control specific services such as point-to-point voice calls or messaging. …