Enum Dialing For Outgoing Calls - Cisco TelePresence Administrator's Manual

Dial plan and call processing
Note: if an ENUM zone and a DNS server have not been configured on the local VCS, calls made using
ENUM dialing could still be placed if the local VCS is neighbored with another VCS that has been
appropriately configured for ENUM dialing. Any ENUM dialed calls will go via the neighbor. This configuration
is useful if you want all ENUM dialing from your enterprise to be configured on one particular system.

ENUM dialing for outgoing calls

For a local endpoint to be able to dial another endpoint using ENUM via your VCS, the following conditions
must be met:
There must be a NAPTR record available in DNS that maps the called endpoint's E.164 number to its URI.
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It is the responsibility of the administrator of the enterprise to which the called endpoint belongs to provide
this record, and they will only make it available if they want the endpoints in their enterprise to be
contactable via ENUM dialing.
You must configure an ENUM zone
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the same as the domain where the NAPTR record for the called endpoint is held.
You must configure your local VCS with the address of at least one
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NAPTR record (and if necessary any resulting URI).
After the ENUM process has returned one or more URIs, a new search will begin for each of these URIs in
accordance with the URI dialing
configuration is required. However, if one or more of the URIs are not locally registered, you may also need to
configure a DNS zone if they are to be located using a DNS lookup.
Calling process
The process below is followed when an ENUM (E.164) number is dialed from an endpoint registered with
your VCS:
1. The user dials the E.164 number from their endpoint.
2. The VCS initiates a search for the E.164 number as dialed. It follows the usual
3. After applying any pre-search transforms, the VCS checks its
configured with a Mode of either:
Any alias, or
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Alias pattern match with a pattern that matches the E.164 number
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4. The target zones associated with any matching search rules are queried in rule priority order.
If a target zone is a neighbor zone, the neighbor is queried for the E.164 number. If the neighbor
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supports ENUM dialing, it may route the call itself.
If a target zone is an ENUM zone, the VCS attempts to locate the endpoint through ENUM. As and
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when each ENUM zone configured on the VCS is queried, the E.164 number is transformed into an
ENUM domain as follows:
i. The digits are reversed and separated by a dot.
ii. The DNS suffix configured for that ENUM zone is appended.
5. DNS is then queried for the resulting ENUM domain.
6. If the DNS server finds at that ENUM domain a NAPTR record that matches the transformed E.164
number (that is, after it has been reversed and separated by a dot), it returns the associated URI to the
VCS.
7. The VCS then initiates a new search for that URI (maintaining the existing hop count). The VCS starts at
the beginning of the search process (applying any pre-search transforms, then searching local and external
Cisco VCS Administrator Guide (X8.1.1)
on your local VCS. This ENUM zone must have a DNS Suffix that is
process. If the URIs belong to locally registered endpoints, no further
DNS server that it can query for the
call routing
search rules to see if any of them are
About ENUM dialing
process.
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