ABSTRACT: GR-3054,Voice over Packet: NGN Trunk Gateway Generic Requirements, sets forth the functionality and interfaces for a Trunk Gateway (TGW) that provides a communications interface between the Public Switched Telephone Network (PSTN) Trunk interface and the Core Network (CN) within the Voice over Packet (VoP) architecture.

One or more TGWs (in the same geographic region) may operate under the control of a Call Connection Agent (CCA) to provide interfaces to the PSTN. For voice traffic arriving at the TGW from the PSTN, the TGW extracts digital voice samples from a specified trunk and inserts them into data packets, which are then routed through the CN to the destination (either to a receiving TGW or an Access Gateway (AGW)). For data traffic arriving at the TGW from the CN, the TGW extracts the voice samples from the received packets, performs the inverse coding conversion, and places the resulting digital signals on a specified trunk for transmission to the destination (via the PSTN). In addition, the TGW may perform signal quality enhancements and silence suppression to send packets only when a talker is active to optimize the utilization of the CN.

This document states in detail all aspects of the TGW functionalities, as well as its interface to the rest of the VoP network elements and management systems. The scope is limited to a set of "generic" functional requirements and interface specifications and does not present capacity, size, and throughput generic requirements, which are all vendor-specific issues.