A gatekeeper is an H.323 entity on a LAN that provides address translation and control access to the LAN for H.323 terminals and gateways.
The gatekeeper can provide other services to the H.323 terminals and gateways, such as bandwidth management and locating gateways.
A gatekeeper maintains a registry of devices in the multimedia network. The devices register with the gatekeeper at startup and request admission to a call from the gatekeeper.
The Cisco VRC supports primary gatekeepers, alternate gatekeepers, overlap gatekeepers, and clustered gatekeepers.
Cisco VRC supports the following Cisco products as H.323 gatekeepers:
3640A Multiservice Platform
3660 Series Multiservice Platform
3700 Series Application Service Routers
7200 Series Routers
Note: VRC support of certain platforms is limited to the Cisco IOS Release running on the device. Refer to VRC Feature Sets for more information.
Cisco gatekeepers perform the following tasks:
Resource Management - Gatekeepers determine the health of H.323 gateways by monitoring registration and unregistration messages and resource availability indicators.
Call Routing - Gatekeepers provide call routing based on destination E.164 addresses. They may use their knowledge of local gateway health levels to make routing decisions in order to increase network availability of the gateways.
Security - Gatekeepers in conjunction with an external server (RADIUS for example) may be used for secure call admission.
CDR Generation - Gatekeepers have limited abilities to generate call detail recording (CDR) records for calls either in addition to or instead of from the gateway.