Gatekeeper Call Scenarios - Nortel BCM50 Configuration Manual

378 Chapter 43 VoIP trunk gateways
A single gatekeeper manages a set of H.323 endpoints. This unit is called a Gatekeeper Zone.
A zone is a logical relation that can unite components from different networks (LANS). These
Gateway zones, such as the BCM, are configured with one or more alias names that are
registered with the gatekeeper. The gatekeeper stores the alias-IP mapping internally and uses
them to provide aliases to IP address translation services. Later, if an endpoint IP address
changes, that endpoint must re-register with the gatekeeper. The endpoint must also re-register
with the gatekeeper during the time to live (TTL) period, if one is specified by the gatekeeper.
Refer to the gatekeeper software documentation for information about changing IP addresses.
Note: A gatekeeper may help to simplify IP configuration or the BCM dialing
plan; however, it will not simplify the network dialing plan.

Gatekeeper call scenarios

The following explains how a call would be processed for the two types of gatekeeper
configurations.
Figure 116 BCM systems with a gatekeeper
DN 321
DN 421
DN 521
This example explains how a call from DN 321 in Ottawa would be made to DN 421 in Santa
Clara. It assumes that call signaling is set to Gatekeeper Resolved and no pre-granted
AdmissionRequest (ARQ) has been issued:
1
BCM Ottawa sends an ARQ to the gatekeeper for DN 421.
2 The gatekeeper resolves DN 421 to 10.10.10.19 and returns this IP in an AdmissionConfirm to
the BCM Ottawa.
NN40020-603 NN40020-603
Figure 116 shows a network with three BCMs and a gatekeeper.
gatekeeper
IP:10.10.10.17
BCM50 Ottawa
IP:10:10:10:18
BCM50 Santa Clara
IP:10:10:10:19
BCM50 Calgary
IP:10:10:10:20
IP network