Denise Donohue & David Mallory 
Cisco Voice Gateways and Gatekeepers [PDF ebook] 

Deployments of voice over IP (Vo IP) networks continue at a rapid pace. Voice gateways are an essential part of Vo IP networks, handling the many tasks involved in translating between transmission formats and protocols and acting as the interface between an IP telephony network and the PSTN or PBX. Gatekeepers and IP-to-IP gateways help these networks scale. Gatekeepers provide call admission control, call routing, address resolution, and bandwidth management between H.323 endpoints including Cisco IOS(R) voice gateways and Cisco(R) Unified Call Manager clusters. IP-to-IP gateways allow Vo IP calls to traverse disparate IP networks. Cisco Voice Gateways and Gatekeepers provides detailed solutions to real-world problems encountered when implementing a Vo IP network. This practical guide helps you understand Cisco gateways and gatekeepers and configure them properly. Gateway selection, design issues, feature configuration, and security and high-availability issues are all covered in depth. The abundant examples, screen shots, configuration snips, and case studies make this a truly practical and useful guide for anyone interested in the proper implementation of gateways and gatekeepers in a Vo IP network. Emphasis is placed on the accepted best practices and common issues encountered in real-world deployments. Cisco Voice Gateways and Gatekeepers is divided into four parts. Part I provides an overview of an IP voice network. Part II is dedicated to voice gateways, including discussions of Media Gateway Control Protocol (MGCP); H.323; Session Initiation Protocol (SIP); voice circuit options; connecting to the PSTN, PBX, and IP WAN; dial plans; digit manipulation; route selection; class of restriction; Survivable Remote Site Telephony (SRST) and MGCP fallback; digital signal processor (DSP) resources; and Tool Command Languaue (Tcl) scripts and Voice XML (VXML). Part III addresses voice gatekeepers, including detailed deployment and configuration. Part IV is dedicated to IP-to-IP gateways.