d (see box) and toll bypass (where long distance voice traffic is trans- ported as packets). More recent applications replicate the functions of today's PBXs and the PSTN to which users are 150 The Telecom Handbook CHAPTER 7 already accustomed. Even newer applications that will be adopted depend upon the marketplace, but may include things such as web-based collaboration and unified messaging. Media Gateway Control Protocol In November, 1998 Level 3 Communications, Inc. and Bellcore (now Telcordia Technologies) announced the merger of their respective technical specifications for a new protocol designed to bridge between the con- ventional circuit-switched PSTN (Public Switched Telephone Network) and the emerging IP (Internet Protocol) packet switched networks. The merged speci- fication, Media Gateway Control Protocol (MGCP) represents a combination of the Internet Protocol De- vice Control (IPDC) specification developed by a consortium formed by Level 3 and made up of leading communications hardware and software companies, and the Simple Gateway Control Protocol (SGCP) de- veloped by Bellcore and Cisco Systems. MGCP is a draft specification (not a standard accepted by IETF) for a physically decomposed gateway, i.e. a protocol converter, the components of which may be distrib- uted across multiple physically distinct devices. MGCP enables external control and management of data com- munications equipment operating at the edge of emerging multi-service packet networks - known as "media gateways" - by software programs known as call agents or media gateway controllers. Examples of media gateway controllers include voice over IP gate- ways, voice over ATM (asynchronous transfer mode) gateways, modem banks, cable modems and set top boxes, soft PBXs and circuit cross-connects. - Compliments Newton's Telecom Dictionary The Telecom Handbook a 151 CONVERGENCE OF VOICE & DATA Internet Offloading Internet offloading is a term used to describe offloading Internet data traffic from a carrier's telephone voice switch onto a 