TANDBERG D14049.01 manual About DNS Domains for Enum, Enum Dialing for Incoming Calls

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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.

About DNS Domains for ENUM

ENUM relies on the presence of NAPTR records as defined by RFC 2915 [7]. These provide the mapping between E.164 numbers and their SIP/H.323 URIs.

RFC 3761 [8], 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

Configuring DNS NAPTR Records

ENUM relies on the presence of NAPTR records, as defined by RFC 2915 [7]. 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).

Non-terminal rules in ENUM are not currently supported by the VCS. For more information on these, see section 2.4.1 of RFC 3761 [8],

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:\1@example.com! 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:\1@example.com states that the E.164 number will be concatenated with @example.com. For example, 1234 will be mapped to

1234@example.com.

•. shows that the replacement field has not been used.

Introduction	Getting	System	System	H.323 & SIP	Registration	Zones and	Call	Firewall	Bandwidth	Maintenance	Appendices
	Started	Overview	Configuration	Configuration	Control	Neighbors	Processing	Traversal	Control
D 14049.01					92
07.2007