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TANDBERG Gatekeeper User Manual

Page 25

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TANDBERG Gatekeeper User Guide

Page 25 of 105

When an endpoint wants to call another endpoint it presents the address it wants to call to the

Gatekeeper using a protocol knows as RAS. The Gatekeeper applies any transforms (see section 5), tries

to resolve the address, and if successful supplies the calling endpoint with information about the called

endpoint.
The destination address can take several forms: IP address, H.323 ID, E.164 alias or a full H.323 URI.
When an H.323 ID or E.164 alias is used, the Gatekeeper looks for a match between the dialed address

and the aliases registered by its endpoints. If no match is found, it may query other Gatekeepers and

Border Controllers.
When dialing by H.323 URI, the destination address resembles an email address. The Gatekeeper first

follows the procedure for matching H.323 IDs. If that fails it looks for a Gatekeeper or Border Controller

responsible for the domain (the part of the URI following the

@

symbol) and queries that device.

Dialing by IP address is necessary when the destination endpoint is not registered with a Gatekeeper or

Border Controller. If it is registered, then one of the other addressing schemes should be used instead

as they are more flexible. From your registered endpoint, dial the IP address of the endpoint you wish to

call. This requires that the Gatekeeper has

xConfiguration Gatekeeper

CallsToUnknownIPAddresses

correctly configured (see section 16.2.4).

When one endpoint calls another, the Gatekeeper is involved in locating the called endpoint. By default,

once the endpoint is located, the Gatekeeper takes no further part in the call signaling. By enabling call

routed mode, all call signaling will be routed through the Gatekeeper. This is useful if you need accurate

information about call start and stop times. Call Detail Records (CDRs) may be extracted from the

Gatekeeper event log.

Note: Traversal calls are always call routed, regardless of the setting of Call Routed Mode.