A Gatekeeper is a very useful, but optional, component of an H.323enabled network. The gatekeeper provides address translation and controls access to the network resources for H.323 terminals, gateways and MCU's.
An endpoint does register itself at a gatekeeper. All H.323 endpoints registered to a single gatekeeper build an H.323 zone. A gatekeeper provides several services to all endpoints in its zone. These services include:
Address translation a gatekeeper translates H.323 aliases into call signaling IP addresses (especially useful for endpoints with dynamic IP addresses). A gatekeeper maintains a database for translation between aliases (such as E.164 addresses) and network addresses.
Admission and access control of endpoints this control can be based on bandwidth availability, limitations on the number of simultaneous H.323 calls, or the registration privileges of endpoints.
Bandwidth management Network administrators can manage bandwidth by specifying limitations on the number of simultaneous calls and by limiting authorization of specific terminals to place calls at specified times.
There are several gatekeepers on the market, including proprietary hardware gatekeepers from Tandberg, Polycom, Cisco, and others, and software based gatekeepers such as GNUGK and DUAL Gatekeeper.
Gatekeeper Provides -
Call Signal Routing