P/N 480-0049-00-13
1-12
Chapter 1: Overview
H.323 Gatekeeper Services
The
Tenor DX
unit’s built-in H.323 gatekeeper performs IP call routing functions, such as call con-
trol and administrative services to another
Tenor DX
unit, or another H.323 endpoint. The gate-
keeper’s functionality complies with the H.323 industry specifications for voice control and
management.
Gatekeeper
A Gatekeeper in an H.323 network provides call control services and other services to H.323 end-
points (i.e., gateways, terminals, and MCUs). The
Tenor DX
has a built-in H.323 gatekeeper which
complies to the H.323 industry specifications for voice control and management. The gatekeeper
performs call routing functions for calls entering and exiting a site.
The Gatekeeper performs IP call routing functions, such as Call Control Signaling and Call Authori-
zation for Gateways, IP phones, and H.323 terminals. The Gatekeeper communicates with other
Gatekeepers through a Border Element. When using a group of
Tenor DX
units, you can assign one
unit as the Gatekeeper for the network. We recommend you configure each as its own gatekeeper.
Tenor DX
supports gatekeeper to gatekeeper communication using the standard LRQ (Location
Request)/LCF (Location Confirm) messaging scheme.
Zone Management
A zone is a group of H.323 defined endpoints controlled by a Gatekeeper. Endpoints can be gate-
ways (i.e.,
Tenor DX
), terminals, and/or multipoint conferencing units (MCUs). Endpoints establish
control channels with a gatekeeper for registration, admission, and security. Call routing information
about the endpoint is sent to the gatekeeper, including: IP address, unit type (gateway, terminal, or
MCU) and routing information (such as phone numbers, number patterns, etc.).
A collection of zones is an administrative domain. An administrative domain provides call routing
services for its zones through gatekeeper to gatekeeper messages or gatekeeper to border element
messages (see below for more information).
Call Registration
When registration from an H.323 endpoint is complete and a call is originated, the call request is
sent to the gatekeeper. The call request provides the Gatekeeper with the dialed number and requests
the routing information. The gatekeeper confirms the dialed number and supplies the endpoint with
the destination IP address. For example, a
Tenor DX
’s gatekeeper will act as the gatekeeper for that
zone and all of the other endpoints will register with it.
Border Element
The
Tenor DX
’s gatekeeper uses a border element to gain access to the routing database of the
administrative domain for the purpose of call completion or any other services that involve commu-
nications with other endpoints out of the administrative domain. The border element functionality is
built into the
Tenor DX
unit, along with the gateway and gatekeeper.
