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Enum dialing for incoming calls, Prerequisites, About dns domains for enum – TANDBERG Security Camera User Manual

Page 125: Configuring dns naptr records, Example, Configuring enum dialing, For incoming calls, Enum dialing

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125

D14049.03
MAY 2008

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TANDBERG

VIDEO COMMUNICATIONS SERVER

ADMINISTRATOR GUIDE

Introduction

Getting Started

Overview and

Status

System

Configuration

VCS

Configuration

Zones and

Neighbors

Call

Processing

Bandwidth

Control

Firewall

Traversal

Maintenance

Appendices

ENUM Dialing

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).

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.

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

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

[email protected]

.

.

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

RFC 3761 [8]

,