An H.323 gatekeeper that provides address translation support only for other gatekeepers.
With a directory gatekeeper, individual gatekeepers do not need to know about other gatekeepers. Instead, a gatekeeper consults its routing table, which provides a default route to a directory gatekeeper. This directory gatekeeper is more knowledgeable about the topology of the network and can forward messages over to the proper gatekeeper. The egress gatekeeper can then contact the originating gatekeeper to complete the call setup.
VRC also supports hierarchical directory gatekeeper configurations. Hierarchical directory gatekeepers (DGKs) describe an H.323 network configuration where multiple levels of gatekeepers (GKs) and DGKs are in the LRQ forwarding path.
Note: VRC does not support simultaneous LRQs being sent on a gatekeeper for a specific zone prefix (LRQ blast), when multiple gatekeepers have the same prefix.
A directory gatekeeper:
Has global dial plan responsibility
Creates a hierarchical architecture of regional gatekeepers
Eliminates the need for a fully meshed gatekeeper configuration
Simplifies overall dial plan management
The directory gatekeeper routes calls outside the local zones by maintaining a list of zone prefix routing tables.
The following Cisco platforms are recognized as directory gatekeepers in VRC:
Cisco 3640 Multiservice Platform
Cisco 3660 Multiservice Platform
Cisco 7200 Series Routers
Note: VRC support of certain platforms are limited to the Cisco IOS release running on the device. Refer to VRC Feature Sets for more information.