125
D14049.03
MAY 2008
Grey Headline
(continued)
TANDBERG
VIDEO COMMUNICATIONS SERVER
ADMINISTRATOR GUIDE
ENUM Dialing
Configuring DNS NAPTR Records
ENUM relies on the presence of NAPTR records, as defined by
. These are used to obtain an H.323 or SIP URI
from an E.164 number.
The record format that the VCS supports is:
order flag preference service regex
•
replacement
where:
order
•
and
preference
determine the order in which
NAPTR records will be processed. The record with the
lowest
order
is processed first, with those with the lowest
preference
being processed first in the case of matching
order
.
flag
•
determines the interpretation of the other fields in this
record. Only the value
u
(indicating that this is a terminal rule)
is currently supported, and this is mandatory.
service
•
states whether this record is intended to describe
E.164 to URI conversion for H.323 or for SIP. Its value must
be either
E2U+h323
or
E2U+SIP
.
regex
•
is a regular expression that describes the conversion
from the given E.164 number to an H.323 or SIP URI.
replacement
•
is not currently used by the VCS and should
be set to
.
(i.e. the full stop character).
About DNS Domains for ENUM
ENUM relies on the presence of NAPTR records to provide the
mapping between E.164 numbers and their SIP/H.323 URIs.
, which is part of a suite of documents that
define the ENUM standard, specifies that the domain for
ENUM - where the NAPTR records should be located for public
ENUM deployments - is
e164.arpa
. However, use of this
domain requires that your E.164 numbers are assigned by an
appropriate national regulatory body. Not all countries are yet
participating in ENUM, so you may wish to use an alternative
domain for your NAPTR records. This domain could reside within
your corporate network (for internal use of ENUM) or it could use
a public ENUM database such as
http://www.e164.org
.
ENUM Dialing for Incoming Calls
Prerequisites
In order for your locally registered endpoints to be reached using
ENUM dialing, you must configure a DNS NAPTR record that
maps your endpoints’ E.164 numbers to their SIP/H.323 URIs.
This record must be located at an appropriate DNS domain
where it can be found by any systems attempting to reach you
via ENUM dialing.
Example
For example, the record:
IN NAPTR 10 100 "u" "E2U+h323" "!^(.*)$!h323:\1@
•
example.com!" .
would be interpreted as follows:
10
•
is the
order
100
•
is the
preference
u
•
is the
flag
E2U+h323
•
states that this record is for an H.323 URI
!^(.*)$!h323:\[email protected]!
•
describes the conversion:
!
•
is a field separator
the first field represents the string to be converted. In this
•
example,
^(.*)$
represents the entire E.164 number
the second field represents the H.323 URI that will be
•
generated. In this example,
h323:\[email protected]
states that the E.164 number will be concatenated with
@example.com
. For example,
1234
will be mapped to
.
.
•
shows that the
replacement
field has not been used.
Non-terminal rules in ENUM are not currently supported
by the VCS. For more information on these, see section
2.4.1 of
