A gatekeeper is an H.323 device that can provide services such as address translation, admission control, bandwidth management, and centralized dial plan management to facilitate network scalability. Gatekeepers can provide these services for H.323 terminals, gateways, and multipoint control unit (MCU). Cisco CallManager can also take advantage of gatekeeper services.
The Cisco IOS gatekeeper feature is supported on the Cisco 2600, 3600, 3700, 2800, 3800, and 7200 families of routers using the appropriate Cisco IOS and feature license.
Although gatekeeper usage is optional, a gatekeeper can provide many benefits to improve scalability and management. It this chapter, you will learn about the benefits that gatekeepers can provide in an IP Telephony network.
This chapter helps you to do the following:
Part I: Voice Gateways and Gatekeepers
Gateways and Gatekeepers
Part II: Gateways
Media Gateway Control Protocol
Session Initiation Protocol
Connecting to the PSTN
Connecting to PBXs
Connecting to an IP WAN
Influencing Path Selection
Configuring Class of Restrictions
SRST and MGCP Gateway Fallback
Using Tcl Scripts and VoiceXML
Part III: Gatekeepers
Part IV: IP-to-IP Gateways
Cisco Multiservice IP-to-IP Gateway
Appendix A. Answers to Chapter-Ending Review Questions