Video Conferencing Gatekeepers: definition and uses

Gatekeepers are added components for H.323 network which gives quite a few services to MCU devices, gateways, and terminals. These services take account of address resolution, endpoint registration, user authentication, admission control, and so forth. With these numbers of functions done by gatekeepers, address resolutions are primarily vital because it makes two endpoints possible for contact with each other exclusive of both endpoints having to identify the IP address of another endpoint.

A gatekeeper may be considered to function in either one of the two available signaling modes. These modes are called gatekeeper routed mode and direct routed mode. The direct router mode is one of the most widely deployed as it is the most proficient. Endpoints in this mode make use RAS protocol to study the remote endpoint of an IP address and calls are directly established using the remote device.

On the other hand, call signaling always goes by through the gatekeeper via the routed mode of the gatekeeper. As the gatekeeper routed mode needs the gatekeeper to gain extra power for processing, it also provides the gatekeeper absolute control over calls and on behalf of endpoints, the capability to offer additional services.

An endpoint which is collectively registered using a single h.323 gatekeeper is commonly known as a zone. The zone does not essentially have to comprise the associated physical topology. Relatively, a zone can be wholly logical and is randomly be identified by the administrator of the network.

Other Facts
One interesting fact about gatekeepers is their ability to neighbor collectively which made possible call resolution taking place among zones. Neighboring assist the usage of dial plans. One example would be global dialing scheme. This dial plan makes possible what we call inter-zone dialing where two endpoints in separate zones will still be able to connect with each other.

Peer Elements and Border Elements

Peer elements and border elements are elective units likened to a Gatekeeper. However, they do not handle endpoints directly and the said elements offer some services which cannot be found stated in each RAS protocol. Factors of a peer or border element can be understood through the administrative domain definition. 

Zone collections that belong to a sole entity control, organization or person, like service provider is called an administrative domain. There may be thousands or hundreds of H323 network elements, video terminals, telephones, or other gateway devices that may be found in every service provider network. 

Service providers may arrange the devices into zones which permit service providers to handle at its best all devices encompassing its control.  When taken together, zones within provider networks for service would then be cited on a separate service provider as one of its administrative domains.   

Border element on the contrary is a signaling unit that in general sits at the administrative domain border and communicates with other domains. The said communication includes important data essential for communication between two administrative domains. For instance, it could be information about call pricing or access authorization information.

Peer elements are units within the administrative domain which is responsible for assisting propagating data gained from border elements of the administrative domain.