ETSI TS 102 172 V1.1.1 (2003-03)

Services and Protocols for Advanced Networks (SPAN); Minimun requirements for interoperability of European ENUM trials

DTS/SPAN-110112

Storitve in protokoli za napredna omrežja (SPAN) – Najmanjše zahteve za preskuse vzajemne obratovalnosti evropskega ENUM

General Information

• Status: Published
• Publication Date: 27-Mar-2003
• Technical Committee: SPAN 11 - SPAN Services, Applications, Numbering, Naming and Addressing (SANNA)
• Current Stage: 12 - Completion
• Due Date: 07-Apr-2003
• Completion Date: 28-Mar-2003
• Ref Project: SIST-TS ETSI/TS 102 172 V1.1.1:2005 - Services and Protocols for Advanced Networks (SPAN); Minimun requirements for interoperability of European ENUM trials

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS ETSI/TS 102 172 V1.1.1:2005
01-januar-2005
Storitve in protokoli za napredna omrežja (SPAN) – Najmanjše zahteve za preskuse
vzajemne obratovalnosti evropskega ENUM
Services and Protocols for Advanced Networks (SPAN); Minimun requirements for
interoperability of European ENUM trials
Ta slovenski standard je istoveten z: TS 102 172 Version 1.1.1
ICS:
33.040.30 Komutacijski in signalizacijski Switching and signalling
sistem systems
SIST-TS ETSI/TS 102 172 V1.1.1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS ETSI/TS 102 172 V1.1.1:2005

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SIST-TS ETSI/TS 102 172 V1.1.1:2005

ETSI TS 102 172 V1.1.1 (2003-03)
Technical Specification


Services and Protocols for Advanced Networks (SPAN);
Minimum requirements for interoperability of
European ENUM trials

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SIST-TS ETSI/TS 102 172 V1.1.1:2005
 2 ETSI TS 102 172 V1.1.1 (2003-03)



Reference
DTS/SPAN-110112
Keywords
ENUM, interoperability
ETSI
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ETSI

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SIST-TS ETSI/TS 102 172 V1.1.1:2005
 3 ETSI TS 102 172 V1.1.1 (2003-03)
Contents
Intellectual Property Rights.4
Foreword.4
1 Scope.5
2 References.5
3 Definitions and abbreviations.6
3.1 Definitions.6
3.2 Abbreviations.7
4 Introduction.8
5 General objectives of ENUM trials within Europe .9
6 ENUM trial interoperability .10
6.1 Constraints in national trials.10
6.2 Interoperability in ENUM trials .12
6.3 Application recommendations to facilitate trial interoperability.13
7 Administrative requirements for interoperability of trials.13
8 DNS requirements for interoperability of trials.14
9 Harmonization of the "ENUMservice" field in the NAPTR Records .14
9.1 Background to minimum requirements for NAPTR use .14
9.2 General conditions.15
9.3 Format and processing of NAPTR records.16
9.4 "ENUMservices" and associated URI Schemes .17
9.4.1 Minimum set of "ENUMservices".17
9.4.1.1 "ENUMservices" for Interactive Media-stream Exchange.17
9.4.1.2 "ENUMservices" for Discrete (non-session related) Messages .17
9.4.1.3 "ENUMservices" for Information Source .18
9.4.1.4 "ENUMservices" for Service Resolution Services.18
9.4.1.5 "ENUMservices" for Session-oriented Message Exchanges.18
9.4.1.6 "ENUMservices" for Instant Information Display - Announcement.19
9.4.1.7 "ENUMservice" for Redirection .19
9.4.2 Additional "ENUMservices".20
9.4.2.1 "ENUMservices" for Location Information .20
9.4.2.2 "ENUMservices" for Public Key Information .20
10 Processing of retrieved information by ENUM Clients .20
10.1 Generic ENUM Clients .20
10.2 ENUM enabled Application Clients.21
10.3 Examples of specific ENUM enabled Application Clients .21
10.3.1 ENUM enabled SIP Client.21
10.3.2 ENUM enabled H323 Client.21
10.3.3 ENUM enabled Email Client.22
10.3.4 ENUM enabled Web Browser .22
10.3.5 ENUM enabled FTP Client.22
10.3.6 ENUM enabled FAX Client.22
10.3.7 ENUM enabled SMS Client .22
10.3.8 ENUM enabled Location Client .22
Annex A (informative): Background to NAPTR Resource Records.23
Annex B (informative): Bibliography.26
History .27

ETSI

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SIST-TS ETSI/TS 102 172 V1.1.1:2005
 4 ETSI TS 102 172 V1.1.1 (2003-03)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
All published ETSI deliverables shall include information which directs the reader to the above source of information.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Services and Protocols for
Advanced Networks (SPAN).
ETSI

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SIST-TS ETSI/TS 102 172 V1.1.1:2005
 5 ETSI TS 102 172 V1.1.1 (2003-03)
1 Scope
The present document contains general guidance on European ENUM trials and the specification for:
• The format, contents and meaning of the information in the NAPTR records that are held by the ENUM Tier 2
Nameserver providers and accessible by DNS.
• The ways in which ENUM client software should interpret and act upon information obtained from NAPTR
records.
The present document is intended to enable interoperability between ENUM trials that are organized in different
countries. This interoperability enables:
• The same ENUM client software to work with NAPTR records generated by different national trials and this
in turn will enable applications that use ENUM to access details of ENUM subscribers in more than one
country without additional modifications.
• Organizations to function as ENUM Registrars and ENUM Tier 2 Nameserver Provider in more than one
national trial.
The present document will therefore add economies of scope to the ENUM trials that will benefit ENUM subscribers,
trial participants, application service providers and ENUM users.
The present document is published as a Technical Specification (TS) at this stage as the contents are unproven. The
intention is to update and upgrade the present document in the light of the results obtained from the trials.
These requirements are therefore specified for the trial phase only, and as such impose no constraints on ENUM when
implemented on a commercial basis following completion of the trial.
Although the present document is focused towards European ENUM trials its use could facilitate interoperability with
ENUM trials in other parts of the world.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE 1: The present document is based additionally on "Work in Progress" at the IETF, documented in Internet
Drafts. This is especially valid for the syntax of the "ENUMservice" field in the NAPTR RR, which is
based on the definitions in Internet Draft , which will supersede
RFC 2916. Within the present document this Internet Draft is referenced as RFC 2916bis.
[1] ITU-T Recommendation E.164: "The international public telecommunication numbering plan".
[2] ETSI TS 102 051: "ENUM Administration in Europe".
[3] IETF RFC 1034: "Domain Names - Concepts and Facilities".
[4] IETF RFC 1035: "Domain Names - Implementation and Specification".
[5] IETF RFC 1123: "Requirements for Internet Hosts -- Application and Support".
ETSI

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[6] IETF RFC 1591: "Domain Name System Structure and Delegation".
[7] IETF RFC 1738: "Uniform Resource Locators (URL)".
[8] IETF RFC 2181: "Clarifications to the DNS Specification", Updates: 1034, 1035, 1123.
[9] IETF RFC 2182: "Selection and Operation of Secondary DNS Servers".
[10] IETF RFC 2255: "The LDAP URL Format".
[11] IETF RFC 2368: "The mailto URL scheme".
[12] IETF RFC 2396: "Uniform Resource Identifiers (URI): Generic Syntax".
[13] IETF RFC 2616: "Hypertext Transfer Protocol -- HTTP/1.1".
[14] IETF RFC 2806: "URLs for Telephone Calls".
[15] IETF RFC 2818: "HTTP Over TLS".
[16] IETF RFC 2916: "E.164 number and DNS".
[17] IETF RFC 3261: "SIP: Session Initiation Protocol".
[18] IETF RFC 3401: "Dynamic Delegation Discovery System (DDDS) Part One: The Comprehensive
DDDS".
[19] IETF RFC 3402: "Dynamic Delegation Discovery System (DDDS) Part Two: The Algorithm".
[20] IETF RFC 3403: "Dynamic Delegation Discovery System (DDDS). Part Three: The Domain
Name System (DNS) Database".
[21] IETF RFC 3405: "Dynamic Delegation Discovery System (DDDS) Part Five: URI.ARPA
Assignment Procedures".
NOTE 2: Also some of the above referenced URI Schemes are currently updated.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TS 102 051 [2], with the exception of
ENUM End User and ENUM Subscriber and the following apply:
NOTE: The term ENUM End user is not used within the present document, ENUM User and ENUM Subscriber
are defined as follows:
ENUM Subscriber: assignee of an E.164 number who has agreed to insert its E.164 number in the ENUM DNS-based
architecture and who requests population of an ENUM domain
NOTE: The ENUM subscriber has full control over the provision and content of the NAPTR Resource Records in
the ENUM Tier 2 Nameserver provider. The ENUM Subscriber is called ENUM End User in
TS 102 051 [2].
ENUM User: person or entity who is querying the ENUM DNS-based architecture using an ENUM-enabled
Application Client or an ENUM Client
NOTE: The ENUM User may be aware only of the application and not of the use of ENUM by the application.
In addition, the following terms and definitions apply:
Application Client: function that provides a user access to the Application Server, e.g. a VoIP client or e-mail client
Application Server: function provided by an Application Service Provider to communicate with the Application Client
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ENUM Client: function that provides access to the DNS which will then return information in the form of NAPTR
records
NOTE: This could take several forms e.g. it may reside as client software on an intelligent terminal used directly
by the ENUM User or be network based, provided upstream as part of the facilities offered by an
Application Service Provider.
ENUM Client Supplier: entity supplying the ENUM Client
ENUM enabled Application Client: Application Client querying ENUM directly for NAPTR Resource Records
ENUM enabled Application Server: Application Server that is using ENUM Clients as part of their application,
e.g. an email server that translates phone numbers in the To:/RCPT fields into their ENUM stored mailto: values
"ENUMservice": parameter held in the Service Field of a NAPTR Resource Record associated with the ENUM DDDS
Application that indicates the class of functionality a given URI Scheme offers
NOTE: According to RFC 2916bis an "ENUMservice" must be registered with the IANA via a description in an
RFC.
Naming Authority Pointer Resource Record (NAPTR): The Naming Authority Pointer Resource Record is specified
in RFC 3403 [20] and a way to encode rule-sets in DNS.
Resource Record: element within the Domain Names System (DNS) containing a data item associated with a domain
name
Uniform Resource Identifier (URI): compact string of characters for identifying an abstract or physical resource
(e.g. an application)
NOTE: An URI is used within a NAPTR Resource Record to point to a specific application.
Uniform Resource Identifier (URI) Schemes: In the Uniform Resource Identifier (URI) definition (RFC 2396,
RFC 1738) there is a field, called "scheme", to identify the type of resource.
NOTE: URI Schemes are defined in RFCs and officially registered with the IANA
(see http://www.iana.org/assignments/uri-schemes).
The following registered URI Schemes are used within the present document:
ftp File Transfer Protocol   RFC 1738 [7]
http Hypertext Transfer Protocol   RFC 2616 [13]
mailto Electronic mail address   RFC 2368 [11]
sip Session Initiation Protocol   RFC 3261 [17]
tel Telephone     RFC 2806 [14]
ldap Lightweight Directory Access Protocol RFC 2255 [10]
https Hypertext Transfer Protocol Secure RFC 2818 [15]
In addition, the not yet registered URI Schemes "h323" and "ENUM" are used. The "tel" URI Schemes is also currently
undergoing modifications. For more information see the related Internet Drafts (work in progress).
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
+NNN Any E.164 number e.g. in the format [phone]
CNAME Canonical Name DNS Resource Record
DDDS Dynamic Delegation Discovery System
DNAME DNS RR for non-terminal DNS Name Redirection
DNS Domain Name System
DNSSEC DNS SECurity extension
EDNS Enhanced Domain Name System
EMS Enhanced Message Service
FAX Facsimile Service
FTP File Transfer Protocol
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H323 Protocol defined in ITU-Recommendation H.323
IANA Internet Assigned Numbers Authority
IETF Internet Engineering Task Force
IP Internet Protocol
ITU-T International Telecommunication Union - Telecommunication Standardization Sector
LDAP Lightweight Directory Access Protocol
MMS Multimedia Messaging Service
NAPTR Naming Authority PoinTeR
NICNAME Unique Identifier ("handle") pointing to personal information in WHOIS
NRA National Regulatory Authority
PC-Phones Phone Clients running on Personal Computers
POSIX Portable Operating System Interface
PSTN Public Switched Telephone Network
RegExp Regular Expression
RFC Request For Comment
RIPE NCC Reseaux IP Europeens Network Control Center
RR (DNS) Resource Record
SIP Session Initiation Protocol
SMS Short Message Service
SW Software
URI Uniform Resource Identifier
VoIP Voice over IP
WHOIS A tool (program) to look up domain names and related information in a database
4 Introduction
Following initial work on the national ENUM trials that are either being planned or taking place in several European
countries, it has been recognized that additional benefits can be gained by facilitating interoperability of the various
trials. The present document aims to assist those countries who wish to expand their trials on a pan-European basis. It
proposes a minimum set of requirements for interoperability.
ENUM Trial interoperability would enable benefits to be gained by sharing experience of different administrative,
technical, operational and user aspects relating to the provision of ENUM capabilities between countries. Each country
will have its own particular architectural, administrative, security and authentication requirements along with its
particular implementation rules. Therefore linking the trials together will enable the various approaches to be evaluated
on a broad basis. This approach would also widen the range of applications and services available to end users as it will
enable them to access those provided by other trialists.
Without commonality of some aspects especially as the format of the NAPTRs designed to support applications,
attempts to link trials together are likely to result in difficulties when trying to access user information in more than one
country.
The results collected from pan-European trials should enable participants to gain valuable information and experience
that will assist when commercial deployment is considered at a later stage.
Involved parties are interested in carrying out trials for ENUM implementation in order to further the resolution of
technical, administrative and operation issues that may define the rules for the commercial deployment in that country.
In order not to presume any implementation solution, it is necessary that the minimum sets of requirements will not
limit the freedom of individual trials and the possibility to take different approaches.
The range of functional entities participating in a national trial depends on the choice of the administrative model in the
country involved. The preferred model in a given country, in turn, depends on, among other things, the national
arrangements for the management of domain names and E.164 numbers. TS 102 051 [2] outlines a number of options
for the administrative model and explains the functions of these roles. Nonetheless, most of the roles (functional
entities) listed are expected to be present in all European trials irrespective of the chosen administrative model:
• ENUM Tier 0 Registry
• ENUM Tier 1 Registry
• ENUM Tier 2 Nameserver Provider
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• ENUM Registrar
• Application Service Provider
• Authentication Agency
• ENUM Subscriber
• ENUM User
For more general information on ENUM see TS 102 051 [2].
5 General objectives of ENUM trials within Europe
Although the objectives for ENUM trials undertaken within any European country must remain totally a national
matter, it should be recognized that additional benefits may be gained from shared experience if some of the general
objectives are shared. Such experience can be further enhanced if different implementations are linked together.
The following list of objectives identifies those that fall into this category and is recommended for trials that are linked
together within Europe in order to share their ENUM experience:
• Understanding the ENUM technology and its potential in providing new applications and services to
customers.
• Evaluating basic DNS infrastructure in relation to ENUM architecture models (for example ENUM Tier 1
Registry, ENUM Registrar, ENUM Tier 2 Nameserver Provider, Authentication and Validation procedures).
• Evaluate and refine the economic benefits and costs of introducing the ENUM capability.
• Exchange of information related to processes e.g. provide process, change process, cessation process, dispute
process.
• Increase the overall size and thereby the benefits of European trials.
• Provide feedback to the relevant standard bodies.
• Provide feedback to NRA/Governments.
Additionally the following list identifies aspects where additional benefits are likely to be gained, although their
inclusion should be dependent upon each specific case and should remain a national issue:
• Experience of registering the ENUM domain name related to the E.164 number and the entry of the necessary
data into DNS zone files.
• Validation initiated by the ENUM Registrar (that the correct delegation is made to the ENUM Subscriber).
• Gaining experience in provisioning ENUM delegation processes between ENUM Registrars and ENUM Tier 1
Registries.
• Exploring options for harmonized provisioning protocols across different countries as well as for unified
validation processes.
• Experience of sharing a common set of applications (e.g. VoIP) from a wider set of users.
ETSI

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 10 ETSI TS 102 172 V1.1.1 (2003-03)
6 ENUM trial interoperability
This clause analyses the issues of interoperability and the constraints on the different roles of the parties involved in
ENUM trials.
6.1 Constraints in national trials
The ENUM Subscriber in a national trial needs to have an E.164 number in the country concerned. Subscribers outside
the countries running ENUM trials have no possibility of involvement as they will not have an E.164 number that can
be supported in the .e164.arpa part of DNS. Since DNS is open, the data relating to all ENUM subscribers is visible to
any Application Service Provider or ENUM User in any country.
The ENUM Registrar acts as an agent to input the ENUM Subscriber's ENUM domain name (E.164 number) into the
ENUM Tier 1 Registry so that the Registry points to the correct ENUM Tier 2 Nameserver Provider in DNS. The
ENUM Registrar needs to be appointed or recognized by the ENUM Tier 1 Registry. The ENUM Registrar may also
have access to the ENUM Tier 2 nameserver to load, amend and delete NAPTR records in the format being used by the
country concerned, or the ENUM Subscriber may load, amend and delete the NAPTR records directly with the
nameserver themselves. Thus the ENUM Registrar's role is nationally specific, although the Registrar may be located
anywhere.
The ENUM Tier 2 Nameserver Provider holds the NAPTR records in the format being used by the country
concerned. The ENUM Tier 1 Registry for the country concerned needs to point to that nameserver. The nameserver
may be located anywhere.
The ENUM Client Supplier is tied to the format of the NAPTR records for the national trial because their ENUM
Clients need to be compatible with the NAPTR records. ENUM Clients may be embedded in Application Clients or
Application Server or may be run as simple stand-alone applications. If the NAPTR records have different formats for
different trials then different versions of the application would be needed to work with ENUM Subscribers in more than
one country.
The Application Service Provider may use ENUM Clients as part of their application. The Application Service
Provider using ENUM may be located anywhere, even in a country that is not running an ENUM trial at all. An
Application Service Provider not using ENUM is out of scope of this specification.
The ENUM User may be located anywhere but, depending on the application, may need special Application Client
software.
Figure 1 shows the relationships involved for two different national trials and for a common model of the relationship
between ENUM Tier 1 Registry, ENUM Registrar and ENUM Tier 2 Nameserver Provider. The ENUM Subscriber
establishes their ENUM entry through the ENUM Registrar who loads this information into the NAPTR records held by
the ENUM name server at Tier 2 level. (Alternatively the ENUM Subscriber may give this information directly to the
ENUM Tier 2 Nameserver Provider). The ENUM Registrar then asks the ENUM Tier 1 Registry to create NS records
for the ENUM Subscriber's ENUM domain name (associated with their assigned E.164 number) to point to the
nameserver that holds the NAPTR records. An ENUM User uses an ENUM Client, either directly or as part of an
ENUM enabled Application, to query the NAPTR records to find the information for the ENUM Subscriber with whom
they wish to communicate. After obtaining the NAPTR records the ENUM User or their application may use this
information to establish the communications between the ENUM User and the ENUM Subscriber.
An ENUM User may either use the ENUM Client directly or use an Application Client. The Application Client in turn
may either use the ENUM Client directly or forward the request to an Application Server, who may use an ENUM
Client to query ENUM on behalf of the user.
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SIST-TS ETSI/TS 102 172 V1.1.1:2005
 11 ETSI TS 102 172 V1.1.1 (2003-03)
National Trial A National Trial B
ENUM Tier 1 ENUM Tier 1
Registry
Registry
Enters
ENUM ENUM
Updates
Enters
Registrar Registrar
ENUM ENUM
Updates
Tier 2 Name Tier 2 Na
...