Multi-Tech Systems MVP-2410 manual Gatekeeper Basics, Introduction, Mandatory Gatekeeper Functions

MultiVOIP User Guide Embedded Gatekeeper

Gatekeeper Basics

Introduction

Gatekeepers are optional within H.323 networks. However, when they are present, gateways (voip units) and other network endpoint devices (like terminals and Multipoint Control Units used in conferences) must use gatekeeper services. There are four functions that H.323 gatekeepers must provide to the network and many other functions, both standard and proprietary, that the gatekeeper may offer to network participants.

Mandatory Gatekeeper Functions

The mandatory gatekeeper functions are address translation, admission control, bandwidth control, and zone management.

Address Translation

The gatekeeper supports aliases, such as conventional E.164 phone numbers, for each endpoint registered within the zone. Users call each other within a zone by simply dialing a number or string of characters instead of an IP address. This function is particularly important when a phone on the circuit- switched network tries to call a phone connected to a gateway on an IP network.

Admission Control

The gatekeeper determines which network participants can and cannot make calls, according to established network permissions and rules. The gatekeeper controls admission using H.225 “RAS” messages (Registration, Admission, Status).

Bandwidth Control

With the MultiVOIP Gatekeeper, the network administrator can specify bandwidth limitations within a gatekeeper’s zone and can specify a bandwidth limit for gateway endpoints. The gatekeeper controls bandwidth using H.225 RAS messages. A gatekeeper may determine there is no bandwidth available for a call or no additional bandwidth available for an ongoing call requesting an increase. Dynamic (situation-dependent) changes in bandwidth allocation are typically called “bandwidth management,” which is considered an optional gatekeeper function.

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