ETSI TR 184 003 V3.1.1 (2010-06)

ETSI TR 184 003 V3.1.1 (2010-06)
Technical Report


Telecommunications and Internet converged Services and
Protocols for Advanced Networking (TISPAN);
Portability of telephone numbers between operators for
Next Generation Networks (NGNs)

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2 ETSI TR 184 003 V3.1.1 (2010-06)



Reference
DTR/TISPAN-04008-NGN-R3
Keywords
NP, portability
ETSI
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3 ETSI TR 184 003 V3.1.1 (2010-06)
Contents
Intellectual Property Rights . 4
Foreword . 4
1 Scope . 5
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 9
4 Background on portability of telephone numbers . 10
5 Overview of Number Portability implementation options . 12
5.1 High level framework of DBs for NGN real time and non-real time environment on different levels . 12
5.2 General assumptions and requirements on the non-real time environment for number portability in
NGNs . 13
5.3 Examples of DBs for NGN real time and non-real time environment . 16
5.3.1 RefNPDB, Tier 1 ENUM DB synchronized with RefNPDB . 16
5.3.2 RefNPDB, no Tier 1 ENUM DB . 17
5.3.3 No physical RefNPDB, no Tier 1 ENUM DB . 18
6 Real time environment for Number Portability in NGN . 18
6.1 Accessing the Real-time Operational Data Base (OpDB) for Number Portability . 18
6.2 Using ENUM as OpDB for Number Portability in NGN . 20
6.3 NGN service layer architecture for Number portability . 23
6.3.1 General . 23
6.3.2 Architecture for the core IMS . 23
6.3.3 Architecture for the PSTN/ISDN Emulation Subsystem . 24
7 NP Routing Information (NRI) and interconnection scenarios with other networks . 25
7.1 Overview . 25
7.2 Method of providing NRI in signalling information in NGNs . 26
7.2.1 IETF provisions for Number Portability . 27
7.2.2 Potential means to convey NRI in SIP . 27
7.2.3 Other aspects . 29
8 Supplementary service aspects . 29
9 Quality of Service aspects . 29
Annex A: Administrative support/process for number portability and OSS aspects . 30
Annex B: Process foruploading and making Number portability data (NPD) available for the
real time environment. 31
B.1 Number Portability Data base (NPDB) implementation options . 31
B.2 RefNPDB . 32
B.3 National OpDB (NOpDB) . 32
B.4 Mesh interconnection of NPDBs . 33
Annex C: Process of uploading and making ENUM data in a Shared ENUM infrastructure
available for the real time environement . 34
History . 35

ETSI

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4 ETSI TR 184 003 V3.1.1 (2010-06)
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).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN).
ETSI

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5 ETSI TR 184 003 V3.1.1 (2010-06)
1 Scope
The present document focuses on number portability (NP) for telephone numbers from national numbering plans (NNP)
for Next Generation Networks (NGNs). These national numbering plans are based on ITU-T Recommendation
E.164 [i.19]. Identifier Portability, i.e. portability of other public identifiers than telephone numbers (e.g. name based
SIP URIs or SIP/tel URIs with a specific phone-context) is outside the scope of the present document, but it is
recognized that this could be the topic of a future separate study.
The present document identifies ways to support portability of telephone numbers (e.g. E.164 numbers) between
Service Providers (SP) - so called "service provider portability" (SPP). The term operator in the present document is
used instead of Service Provider and the report identifies functionality needed to support the following portability
scenarios:
• Between NGN operators;
• From NGN operators to PSTN/ISDN SPs;
• From PSTN/ISDN SPs to NGN operators.
NOTE: The types of telephone numbers that are subject to portability is a national matter, and are therefore not
addressed in the present document.
The support for number portability can be divided in two distinct processes:
a) the process of porting a telephone number from one operator to another; and
b) the process to establish a call to a telephone number that may be ported.
The first process a) would include the actions from:
• the request of the telephone number to be ported;
• the distribution and storage of NP Data (NPD) that the telephone number is ported from one operator to
another operator, and at which time the porting takes effect;
• making the necessary NPD available to the data base environment that are accessible in real time from the
communication processing systems;
• allowing communication establishment to the operator that currently serves the telephone number.
The second process b) would include information:
• how data bases in the real time environment can be accessed and NPD can be retrieved;
• from where the NPD can be retrieved;
• how the NPD can be carried and used and transformed to NP Routing Information (NRI) for the establishment
of the communication to the current operator.
The detailed process of porting a telephone number and storage and distribution of NPD is essentially an administrative
process, that may differ very much from country to country. The present document considers mainly the following:
• NGN network architecture specific for number portability;
• how the NPD obtained from the real time data base environment is used to route sessions, based on NRI,
within and between networks.
However, some information relating to the process of porting a telephone number is provided in annex A, and how to
populate and make NPD and ENUM data available to the real time environment is provided in annexes B and C.
Clause 5 gives an high level framework concerning different kind of DBs in the real time and in the non-real time
environment of the NGN on different levels (i.e. operator, national and international level).
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6 ETSI TR 184 003 V3.1.1 (2010-06)
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) 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: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 101 119 (V1.1.1): "Network Aspects (NA); High level description of number
portability".
[i.2] ETSI TR 101 122 (V1.1.1): "Network Aspects (NA); Numbering and addressing for Number
Portability".
[i.3] ETSI TR 101 118 (V1.1.1): "Network Aspects (NA); High level network architecture and
solutions to support number portability".
[i.4] ITU-T Supplement 2 to E.164/I.331/Q.11 (2009): "Supplement 2: Number portability".
[i.5] ETSI TR 101 697 (V1.1.1): "Number Portability Task Force (NPTF); Guidance on choice of
network solutions for service provider portability for geographic and non-geographic numbers".
[i.6] ETSI TS 184 006: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Interconnection and Routeing requirements related to
Numbering and Naming for NGNs; NAR Interconnect".
[i.7] IETF RFC 4769: "IANA Registration for an Enumservice Containing Public Switched Telephone
Network (PSTN) Signaling Information".
[i.8] IETF RFC 4694: "Number Portability Parameters for the tel URI".
[i.9] ETSI TS 182 006: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Stage 2 description
(3GPP TS 23.228 V7.2.0, modified)".
[i.10] ITU-T Recommendation E.101 (2009): "Definitions of terms used for identifiers (names, numbers,
addresses and other identifiers) for public telecommunication services and networks in the E-series
Recommendation".
[i.11] IETF RFC 3761: "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)".
[i.12] ETSI TS 184 010: "Telecommunications and Internet Converged Services and Protocols for
Advanced Networks (TISPAN) ENUM & DNS Principles for an Interoperator IP backbone
network".
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7 ETSI TR 184 003 V3.1.1 (2010-06)
[i.13] ETSI TS 123 228: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; IP Multimedia Subsystem (IMS); Stage 2
(3GPP TS 23.228)".
[i.14] ETSI ES 282 002: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); PSTN/ISDN Emulation Sub-system (PES); Functional
architecture".
[i.15] ETSI TS 129 235: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Interworking between SIP-I based circuit-switched
core network and other networks (3GPP TS 29.235)".
[i.16] IETF RFC 3261: "SIP: Session Initiation Protocol".
[i.17] ETSI TR 101 698: "Number Portability Task Force (NPTF); Administrative support of service
provider portability for geographic and non-geographic numbers".
[i.18] IETF RFC 3966: "The tel URI for Telephone Numbers".
[i.19] ITU-T Recommendation E.164 (2005): "The international public telecommunication numbering
plan".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
data base query function: function whereby a data base is accessed in order to ascertain whether a telephone number
is ported, and if it is, a Routeing Number or a domain name is obtained that may be used to route the call to a
destination
donating network: network from which the number has been ported out in the last porting process
NOTE: Source TR 101 122 [i.2].
donor network: initial Network where a number was assigned by the Numbering Plan Administrator before ever being
ported
E.164 number: string of decimal digits that satisfies the three characteristics of structure, number length and
uniqueness specified in ITU-T Recommendation E.164 [i.19]
NOTE 1: The number contains the information necessary to route the call to the end user or to a point where a
service is provided.
NOTE 2: Source ITU-T Recommendation E.101 [i.10].
ENUM data: data for mapping an E.164 number to an URI
NOTE: Mapping can be done directly or by providing pointers to other ENUM DBs according to ordinary DNS
procedures.
ENUM DB: real time data base that store ENUM data. It is used to resolve E.164 numbers to URIs at session initiation
ENUM query: query made on the Shared ENUM infrastructure in order to resolve a specific E.164 number to an
routable URI
location portability: ability of an end user to retain the same telephone number when moving from one location to
another
National Operational Data Base (NOpDB): real time common data base that store data from the NPDB to be
transformed to NRI used for routing by all operators within one country
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8 ETSI TR 184 003 V3.1.1 (2010-06)
NPA Data: off-line data published by the numbering plan administrator (NPA) which provide the number block
assignments to operators that provides services within the jurisdiction of the NPA
NOTE: If the telephone numbers are subject to number portability the actual operator serving a specific telephone
number may differ from the one provided by these data. In cases where telephone numbers are assigned
directly to end users, the operator chosen by the end user to provide services is due to spread information
that he is serving that telephone number.
NPA DB: non-real time data base that store NPA Data run by the NPA
NP Data (NPD): off-line data linked to ported telephone numbers as they are stored in and retrieved from the NPDB
NOTE: This data consist of a list of ported telephone numbers with associated domain names or routeing numbers
and optionally further information of traffical and/or administrative nature. Normally these data are
provided in a format which requests for further processing in order to render routeing information.
NPDB: non-real time data base that is used to store NP Data
NOTE: As an option the NPDB may contain information for all telephone numbers (i.e. also non-ported
telephone numbers). Such additional information would be based on NPA Data.
NP query: query using the data base query function
NP Routing Information (NRI): information needed to complete the E.164 number based communications request to
ported telephone numbers
OpDB: real time data base that store data from the NPDB to be transformed to NRI used for routing
operator: entity providing public telecommunications networks and/or public telecommunication services
ported number: number that has been subject to number portability
NOTE: Source TR 101 122 [i.2].
recipient network: network where a number is located after being ported
NOTE: Source TR 101 122 [i.2].
RefNPDB: non-real time reference NPDB
NOTE: It is national matter whether there is one physical RefNPDB or a logical one, which may be distributed
over the operators involved
Service Provider Portability (SSP): ability of an end user to retain the same telephone number when changing from
one service provider to another
service portability: ability of an end user to retain the same telephone number when changing from one type of service
to another
Shared ENUM Infrastructure: inter-operator infrastructure according to ENUM technology as defined in
RFC 3761 [i.11], used by the originating or an intermediate network to map a specific E.164 number into a URI that
identifies the network actually serving that specific E.164 number
NOTE: Shared ENUM infrastructure is different from User ENUM infrastructure [i.11] where the end-user may
register his E.164 number to be associated with a URI of his desire.
telephone number; directory number: number, derived from the E.164 numbering plan, used by the originating party
to establish a call/communication to an end user or a service
NOTE 1: The number may also be used for identification/presentation services and may also be published in
different directories and/or directory enquiry services.
NOTE 2: Source ITU-T Recommendation E.101 [i.10]. The E.101 definition has been modified here to be
independent of the network technology, e.g. NGN, PSTN/ISDN and other technologies.
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9 ETSI TR 184 003 V3.1.1 (2010-06)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACQ All Call Query
AGCF Access Gateway Control Function
AGW Access GateWay
AS Application Server
BGCF Breakout Gateway Control Function
CC Country Code
CdPN Called Party Number
CS Circuit Switched
CSCF Call Server Control Function
CS-IBCF CS (domain) IBCF
CS-TrGW CS (domain) TrGW
DB Data Base
DN Directory Number
DNS Domain Name System
ENUM tElephone NUMber mapping
FQDN Fully Qualified Domain Name
I/S-CSCF Interrogating/Serving Call Server Control Function
IAM Initial Address Message
IBCF Interconnection Border Control Function
IETF Internet Engineering Task Force
IMS IP Multimedia Subsystem
INAP Inteligent Network Application Protocol
ISDN Integrated Services Digital Network
ISUP ISDN User Part
IWF InterWorking Function
LNP Local Number Portability
MAP Mobile Application Part
MGCF Media Gateway Control Function
MGW Media GateWay
MRFC Multimedia Resource Function Controller
N(S)N National (Significant) Number
NAPTR Naming Authority Pointer
NDC National Destination Code
NGN Next Generation Network
NNP National Numbering Plan
NOpDB National Operational Data Base
NP Number Portability
NPA DB Numbering Plan Administrator Data Base
NPA Numbering Plan Administrator
NPD NP Data
NPDB Number Portability Data Base
npdi NP Database Dip Indicator
NRA National Regulatory Authority
NRI NP Routing Information
OP Operator
OpDB Operational Data Base
OR Onward Routeing
OSS Operations Support Systems
P-CSCF Proxy-Call Session Control Function
PES PSTN/ISDN Emulation Subsystem
PLMN Public Land Mobile Network
PSTN Public Switched Telephone Network
RefNPDB Reference Number Portability Data Base
rn routing number
S-CSCF Serving CSCF
SIP Session Initiation Protocol
SIP-I SIP with encapsulated ISUP
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10 ETSI TR 184 003 V3.1.1 (2010-06)
SLF Subscription Locator Function
SN Subscriber Number
SP Service Provider
SPP Service Provider Portability
SS7 Signalling System Number 7
SS-CF Soft Switch Control Function
TCAP Transaction Capabilities Application Part
TDM Time Division Multiplexing
TGCF Trunking Gateway Control Function
UE User Equipment
UPSF User Profile Server Function
URI Uniform Resource Identifier
4 Background on portability of telephone numbers
The service features associated with portability of telephone numbers (Number Portability) are independent from the
technology with which they are implemented. The requirements that have been defined by ITU-T and ETSI in the past
are recommended to be carried forward to NGN.
In particular the service provider portability is referring only to the delivery of publicly available electronic
communication services which are delivered by means of telephone numbers (e.g. E.164 numbers) and other
capabilities related to them that ought to be implemented also through NGN networks.
The main focus of the present document is the portability of telephone numbers. Number Portability (NP) only refers to
the E.164 number part of the user's public identifier that, in NGN, can be represented with either a tel URI or a SIP URI
(the user part of SIP URI) with the parameter "user=phone".
In the PSTN/ISDN network environment, three types of number portability have been recognized:
• Service Provider portability (SPP);
• Location portability;
• Service portability.
Definitions for these are shown in clause 3.1.
Strictly, in the NGN environment we should be talking about "portability of public identifiers" between operators. The
type of public identifier portability considered in the present document is portability between operators providing
equivalent electronic communication services - the NGN equivalent of service provider portability as defined in
clause 3.1. References to number portability elsewhere in the document should be taken to have this meaning.
The following portability types are out of the scope of this study:
• Location Portability;
• Service Portability.
The decision on the method of implementation of number portability in PSTN/ISDN networks within a particular
country has been made at a national level and that will continue to be the case also in the NGN context. This decision
will ultimately be made by National Regulatory Authorities (NRAs), with operators and equipment suppliers
contributing to the process. For this reason, the present document does not mandate a particular implementation for
NGNs.
Factors that may influence national decisions will include the following:
• the inherent capabilities offered by the NGN architecture;
• the relative costs of implementing the various options in an NGN environment;
• service interconnect scenarios and requirements;
• interoperability with existing legacy NP solutions;
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11 ETSI TR 184 003 V3.1.1 (2010-06)
• experience from existing NP solutions;
• different options to handle NP data in the non-real time environment and how to make this data available to
the networks.
The responsibilities of the entity delivering service provider portability as described in TR 101 119 [i.1] are still valid
and applicable in the NGN, in particular the responsibilities to route a call to the ported number are consistent with the
Routeing Roles defined in the TS 184 006 [i.6] including donor, donating and recipient roles.
On the basis of the description provided by TR 101 122 [i.2] the NGN will not change the features of the service
providers portability: the main routeing problem to solve when Number Portability (NP) is involved is to be able to
route the call to the recipient network. Also appropriate non-real time number portability data base environment has to
be agreed by operators in advance, assuring population and updating procedures to OpDBs, as a basis for voiceband
calls/sessions routing process.
Triggering function for NP resolution can be provided by different operators acting specific NP role (originating, donor
or donating).
It should be noted that, in a circuit-switched telephone network SPP technical solutions were based upon the use of the
SS7 stack (specifically ISUP and Core INAP protocols). SPP solutions, also in an NGN environment focus are on
services with telephone numbers and should be evaluated on NGN technologies and architectures; also query
mechanisms have to be considered based on innovative and legacy technologies and data base systems.
Where NGN SPP functionality differs from that already in place, it is recommended that the NGN SPP functionality can
co-exist and interoperate with the existing solution for services in the legacy networks.
NGN technology should consider utilizing existing technical capabilities such as Reference NPDB (RefNPDB)
implementations where they can assist in providing the required functionality for distributing NPD to the real-time
environment.
More detailed information on the various technical options appropriate to legacy networks has been provided in detail in
earlier ETSI documents, as follows:
• TR 101 119 [i.1];
• TR 101 122 [i.2];
• TR 101 118 [i.3];
• TR 101 697 [i.5].
When examining Number Portability, it is instructive to consider the domains to which it applies. In addition to the
portability domain (P), i.e. the scope of portability, there is another domain, the routeing domain (R) which describes
that part of the network(s) that is able to recognize a number as ported, and route accordingly.
In figure 4.1, area 'P' is the domain over which it is possible to port a number, area 'R' is that part of the network that
recognizes a number is ported, and carries out appropriate action. Domain W describes the rest of network, tha
...