Gatekeeper Functionality

The concept of a zone is used to define the group of H.323 devices that an individual gatekeeper controls. That is, the devices that belong to the zone register with the controlling gatekeeper. Zones can cross subnets, and a gatekeeper can manage devices in one or more subnets. Up to 100 zones can be registered to an individual gatekeeper.

Prior to H.323 Version 2, only one gatekeeper could be active in a zone at a time. H.323 Version 2 introduced the concept of alternate gatekeepers. Implementing the alternate gatekeeper feature allows multiple gatekeepers to control one zone. This helps to provide redundancy and load sharing for large installations. The gateway must also support the alternate gatekeeper to use this feature.

Figure 16-1 is an example of two gatekeepers controlling devices in two separate zones. Notice that communication and signaling can cross between the zones.

Figure 16-1. Multiple Gatekeepers and Zones

The following are services for voice calls that the gatekeeper can provide:

Категории