Uri Dialing And Firewall Traversal; About Enum Dialing; Enum Dialing Process - Cisco TelePresence Video Communication Server Administrator's Manual

How you add the DNS records depends on the type of DNS server you are using. Instructions for
setting up two common DNS servers are given in the
For locally registered H.323 endpoints to be reached using URI dialing, either:
the H.323 endpoints should register with the VCS using an address in the format of a URI
n
an appropriate transform should be written to convert URIs into the format used by the H.323
n
registrations. An example would be a deployment where H.323 endpoints register with an alias, and
incoming calls are made to alias@domain.com. A local transform is then configured to strip the
@domain, and the search is made locally for alias. See
numbers for an example of how to do this.
SIP endpoints always register with an AOR in the form of a URI, so no special configuration is
required.
Several mechanisms could have been used to locate the VCS. You may want to enable calls placed to
user@<IP_address> to be routed to an existing registration for user@example.com. In this case
you would configure a pre-search transform
URI and replace it with the suffix of example.com.

URI dialing and firewall traversal

If URI dialing via DNS is being used in conjunction with firewall traversal, DNS zones should be
configured on the VCS Expressway and any VCSs on the public network only. VCSs behind the
firewall should not have any DNS zones configured. This will ensure that any outgoing URI calls made
by endpoints registered with the VCS will be routed through the VCS Expressway.
In addition, the DNS records for incoming calls should be configured with the address of the VCS
Expressway as the authoritative gatekeeper/proxy for the enterprise (the
section for more information). This ensures that incoming calls placed using URI dialing enter the
enterprise through the VCS Expressway, allowing successful traversal of the firewall.

About ENUM dialing

ENUM dialing allows an endpoint to be contacted by a caller dialing an E.164 number - a telephone
number - even if that endpoint has registered using a different format of alias.
Using ENUM dialing, when an E.164 number is dialed it is converted into a URI using information
stored in DNS. The VCS then attempts to find the endpoint based on the URI that has been returned.
The ENUM dialing facility allows you to retain the flexibility of URI dialing while having the simplicity
of being called using just a number - particularly important if any of your callers are restricted to dialing
using a numeric keypad.
The VCS supports outward ENUM dialing by allowing you to configure ENUM zones on the VCS.
When an ENUM zone is queried, this triggers the VCS to transform the E.164 number that was dialed
into an ENUM domain which is then queried for using DNS.
Note: ENUM dialing relies on the presence of relevant DNS NAPTR records for the ENUM domain
being queried. These are the responsibility of the administrator of that domain.

ENUM dialing process

When a VCS is attempting to locate a destination endpoint using ENUM, the general process is as
follows:
Cisco VCS Administrator Guide (X6.1)
DNS configuration examples
Stripping @domain for dialing to H.323
that would strip the IP_address suffix from the incoming
Dial plan and call processing
section.
DNS configuration examples
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