zones in priority order).From this point, as it is now searching for a SIP/H.323 URI, the process for
URI
dialing
is followed.
In this example, we want to call Fred at Example Corp. Fred’s endpoint is actually registered with the URI
fred@example.com
, but to make it easier to contact him his system administrator has configured a DNS
NAPTR record mapping this alias to his E.164 number:
+44123456789
.
We know that the NAPTR record for
example.com
uses the DNS domain of
e164.arpa
.
1. We create an ENUM zone on our local VCS with a
DNS suffix
of
e164.arpa
.
2. We configure a search rule with a
Pattern match mode
of
Any alias
, and set the
Target
to the ENUM
zone. This means that ENUM will always be queried regardless of the format of the alias being searched
for.
3. We dial
44123456789
from our endpoint.
4. The VCS initiates a search for a registration of
44123456789
and the search rule of
Any alias
means the
ENUM zone is queried. (Note that other higher priority searches could potentially match the number first.)
5. Because the zone being queried is an ENUM zone, the VCS is automatically triggered to transform the
number into an ENUM domain as follows:
a. The digits are reversed and separated by a dot:
9.8.7.6.5.4.3.2.1.4.4
.
b. The
DNS suffix
configured for this ENUM zone,
e164.arpa
, is appended. This results in a
transformed domain of
9.8.7.6.5.4.3.2.1.4.4.e164.arpa
.
6. DNS is then queried for that ENUM domain.
7. The DNS server finds the domain and returns the information in the associated NAPTR record. This tells
the VCS that the E.164 number we have dialed is mapped to the SIP URI of
fred@example.com
.
8. The VCS then starts another search, this time for
fred@example.com
. From this point the process for
URI dialing is followed, and results in the call being forwarded to Fred’s endpoint.
Configuring zones and search rules for ENUM dialing
To support ENUM dialing, you must configure an ENUM zone and related search rules for each ENUM
service used by remote endpoints.
Adding and configuring ENUM zones
To set up an ENUM zone:
1. Go to
Configuration > Zones > Zones
.
2. Click
New
. You are taken to the
Create zone
page.
3. Enter a
Name
for the zone and select a
Type
of
ENUM
.
4. Configure the ENUM zone settings as follows:
Field
Guidelines
Hop count
The
hop count
specified for an ENUM zone is applied in the same manner as hop counts for
other zone types. The currently applicable hop count is maintained when the VCS initiates a
new search process for the alias returned by the DNS lookup.
DNS suffix
The suffix to append to a transformed E.164 number to create an ENUM host name. It
represents the DNS zone (in the domain name space) to be queried for a NAPTR record.
Cisco VCS Administrator Guide (X8.1.1)
Page 213 of 507
Dial plan and call processing
About ENUM dialing