Uri Dialing; Making A Call Using Uri Dialing; Receiving A Call Using Uri Dialing - TANDBERG Gatekeeper User Manual

TANDBERG Gatekeeper User Manual

7 URI Dialing

7.1 Making a call using URI dialing

If an alias is not located in the Gatekeeper's list of registrations, it may attempt to find an
authoritative Gatekeeper through the DNS system.
URI dialing makes it easier for endpoints registered with different Gatekeepers or Border Con-
trollers to call each other. Without URI dialing, you need to neighbor all the systems to each other.
This does not scale well as the number of systems grows. It is also inconvenient for making one
off calls to endpoints registered with previously unknown systems.
Using URI dialing, you call using an H.323 URI which looks like an email address. The destination
Gatekeeper is found from the domain name — the part after the @ — in the same way that an
email server is found.
The decision as to whether or not to use URI dialing is governed by the current state of:
xConfiguration Gatekeeper DNSResolution Mode: <On/Off>
or using the web interface on the Gatekeeper Configuration Gatekeeper page
You will also need to configure a DNS server for the systems to query. This is set using:
xConfiguration IP DNS Server 1 Address: <address>
or using the web interface on the System Configuration IP page (see Figure 18 for the IP
Configuration screen).
If you want others to be able to reach you using URI dialing, add a record to your DNS information
as described in Appendix A
Endpoints will typically register with the Gatekeeper without their domain name. The Gatekeeper
needs to match a request for fred@example.com to a registration for fred. To do this, it must be
configured with the name of the domain in which its endpoints belong. This is set using
xConfiguration Gatekeeper LocalDomain DomainName: <name>
If URI dialing is being used in conjunction with firewall traversal, DNSResolution Mode should
only be enabled on the Border Controller and on any Gatekeepers on the public network. The
DNS records should be updated with the address of the Border Controller as the authoritative
Gatekeeper for the enterprise. This ensures that calls placed using URI dialing enter and leave
the enterprise through the Border Controller, allowing successful traversal of the firewall.
The LocalDomain DomainName should be set on both the Gatekeeper and the Border Controller.
Any Alternates should also have the same LocalDomain Domain Name.

7.2 Receiving a call using URI dialing

When a call is placed using URI dialing, the Gatekeeper will receive a request containing the
dialed URI in the form user@host. As described in section 7.3 several mechanisms could have
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