draft-ietf-modern-problem-framework-01.txt   draft-ietf-modern-problem-framework-02.txt 
Network Working Group J. Peterson Network Working Group J. Peterson
Internet-Draft T. McGarry Internet-Draft T. McGarry
Intended status: Informational NeuStar, Inc. Intended status: Informational NeuStar, Inc.
Expires: January 8, 2017 July 7, 2016 Expires: September 14, 2017 March 13, 2017
Modern Problem Statement, Use Cases, and Framework Modern Problem Statement, Use Cases, and Framework
draft-ietf-modern-problem-framework-01.txt draft-ietf-modern-problem-framework-02.txt
Abstract Abstract
The functions of the public switched telephone network (PSTN) are The functions of the public switched telephone network (PSTN) are
rapidly migrating to the Internet. This is generating new rapidly migrating to the Internet. This is generating new
requirements for many traditional elements of the PSTN, including requirements for many traditional elements of the PSTN, including
telephone numbers (TNs). TNs no longer serve simply as telephone telephone numbers (TNs). TNs no longer serve simply as telephone
routing addresses, they are now identifiers which may be used by routing addresses: they are now identifiers which may be used by
Internet-based services for a variety of purposes including session Internet-based services for a variety of purposes including session
establishment, identity verification, and service enablement. This establishment, identity verification, and service enablement. This
problem statement examines how the existing tools for allocating and problem statement examines how the existing tools for allocating and
managing telephone numbers do not align with the use cases of the managing telephone numbers do not align with the use cases of the
Internet environment, and proposes a framework for Internet-based Internet environment, and proposes a framework for Internet-based
services relying on TNs. services relying on TNs.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 8, 2017. This Internet-Draft will expire on September 14, 2017.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 1. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Actors . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Actors . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 7 2.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Data Management Architectures . . . . . . . . . . . . . . 8 2.3. Data Management Architectures . . . . . . . . . . . . . . 8
3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Acquisition . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Acquisition . . . . . . . . . . . . . . . . . . . . . . . 11
4.1.1. CSP Acquires TNs from Registrar . . . . . . . . . . . 11 4.1.1. CSP Acquires TNs from Registrar . . . . . . . . . . . 12
4.1.2. User Acquires TNs from CSP . . . . . . . . . . . . . 12 4.1.2. User Acquires TNs from CSP . . . . . . . . . . . . . 12
4.1.3. CSP Delegates TNs to Another CSP . . . . . . . . . . 12 4.1.3. CSP Delegates TNs to Another CSP . . . . . . . . . . 13
4.1.4. User Acquires TNs from a Delegate . . . . . . . . . . 13 4.1.4. User Acquires TNs from a Delegate . . . . . . . . . . 13
4.1.5. User Acquires Numbers from Registrar . . . . . . . . 13 4.1.5. User Acquires TNs from Registrar . . . . . . . . . . 14
4.2. Management . . . . . . . . . . . . . . . . . . . . . . . 13 4.2. Management . . . . . . . . . . . . . . . . . . . . . . . 14
4.2.1. Management of Administrative Data . . . . . . . . . . 13 4.2.1. Management of Administrative Data . . . . . . . . . . 14
4.2.1.1. CSP to Registrar . . . . . . . . . . . . . . . . 14 4.2.1.1. CSP to Registrar . . . . . . . . . . . . . . . . 15
4.2.1.2. User to CSP . . . . . . . . . . . . . . . . . . . 14 4.2.1.2. User to CSP . . . . . . . . . . . . . . . . . . . 15
4.2.1.3. User to Registrar . . . . . . . . . . . . . . . . 15 4.2.1.3. User to Registrar . . . . . . . . . . . . . . . . 15
4.2.2. Management of Service Data . . . . . . . . . . . . . 15 4.2.2. Management of Service Data . . . . . . . . . . . . . 16
4.2.2.1. CSP to other CSPs . . . . . . . . . . . . . . . . 15 4.2.2.1. CSP to other CSPs . . . . . . . . . . . . . . . . 16
4.2.2.2. User to CSP . . . . . . . . . . . . . . . . . . . 16 4.2.2.2. User to CSP . . . . . . . . . . . . . . . . . . . 16
4.2.3. Managing Change . . . . . . . . . . . . . . . . . . . 16 4.2.3. Managing Change . . . . . . . . . . . . . . . . . . . 17
4.2.3.1. Changing the CSP for an Existing Communications 4.2.3.1. Changing the CSP for an Existing Communications
Service . . . . . . . . . . . . . . . . . . . . . 16 Service . . . . . . . . . . . . . . . . . . . . . 17
4.2.3.2. Terminating a Service . . . . . . . . . . . . . . 16 4.2.3.2. Terminating a Service . . . . . . . . . . . . . . 17
4.3. Retrieval . . . . . . . . . . . . . . . . . . . . . . . . 17 4.3. Retrieval . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.1. Retrieval of Public Data . . . . . . . . . . . . . . 17 4.3.1. Retrieval of Public Data . . . . . . . . . . . . . . 18
4.3.2. Retrieval of Semi-restricted Administrative Data . . 18 4.3.2. Retrieval of Semi-restricted Administrative Data . . 18
4.3.3. Retrieval of Semi-restricted Service Data . . . . . . 18 4.3.3. Retrieval of Semi-restricted Service Data . . . . . . 19
4.3.4. Retrieval of Restricted Data . . . . . . . . . . . . 18 4.3.4. Retrieval of Restricted Data . . . . . . . . . . . . 19
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
7. Security Considerations . . . . . . . . . . . . . . . . . . . 19 7. Security Considerations . . . . . . . . . . . . . . . . . . . 20
8. Informative References . . . . . . . . . . . . . . . . . . . 20 8. Informative References . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Problem Statement 1. Problem Statement
The challenges of utilizing telephone numbers (TNs) on the Internet The challenges of utilizing telephone numbers (TNs) on the Internet
have been known for some time. Internet telephony provided the first have been known for some time. Internet telephony provided the first
use case for routing telephone numbers on the Internet in a manner use case for routing telephone numbers on the Internet in a manner
similar to how calls are routed in the public switched telephone similar to how calls are routed in the public switched telephone
network (PSTN). As the Internet had no service for discovering the network (PSTN). As the Internet had no service for discovering the
endpoints associated with telephone numbers, ENUM [3] created a DNS- endpoints associated with telephone numbers, ENUM [3] created a DNS-
based mechanism for resolving TNs in an IP environment, by defining based mechanism for resolving TNs in an IP environment, by defining
procedures for translating TNs into URIs for use by protocols such as procedures for translating TNs into URIs for use by protocols such as
SIP [2]. The resulting database was designed to function in a manner SIP [2]. The resulting database was designed to function in a manner
similar to the systems that route calls in the PSTN. Originally, it similar to the systems that route calls in the PSTN. Originally, it
was envisioned that ENUM would be deployed as a global hierarchical was envisioned that ENUM would be deployed as a global hierarchical
service, though in practice, it has only been deployed piecemeal by service, though in practice, it has only been deployed piecemeal by
various parties. Most notably, ENUM is used as an internal network various parties. Most notably, ENUM is used as an internal network
function, and is hardly used between service provider networks. The function, and is rarely used between service provider networks. The
original ENUM concept of a single root, e164.arpa, proved to be original ENUM concept of a single root, e164.arpa, proved to be
politically and practically challenging, and less centralized models politically and practically challenging, and less centralized models
have thus flourished. Subsequently, the DRINKS [4] framework showed have thus flourished. Subsequently, the DRINKS [4] framework showed
ways that authorities might provision information about TNs at an ways that service providers might provision information about TNs at
ENUM service or similar Internet-based directory. These technologies an ENUM service or similar Internet-based directory. These
have also generally tried to preserve the features and architecture technologies have also generally tried to preserve the features and
familiar to the PSTN numbering environment. architecture familiar to the PSTN numbering environment.
Over time, Internet telephony has encompassed functions that differ Over time, Internet telephony has encompassed functions that differ
substantially from traditional PSTN routing and management, substantially from traditional PSTN routing and management,
especially as non-traditional providers have begun to utilize especially as non-traditional providers have begun to utilize
numbering resources. An increasing number of enterprises, over-the- numbering resources. An increasing number of enterprises, over-the-
top Voice over IP providers, text messaging services, and related top voice-over-IP (VoIP) providers, text messaging services, and
non-carrier services have become heavy users of telephone numbers. related non-carrier services have become heavy users of telephone
An enterprise, for example, could deploy an IP PBX that receives a numbers. An enterprise, for example, can deploy an IP PBX that
block of telephone numbers from a carrier and then in turn distribute receives a block of telephone numbers from a carrier and then in turn
those numbers to new IP telephones when they associate with the PBX. distribute those numbers to new IP telephones when they associate
Internet services offer users portals where they can allocate new with the PBX. Internet services offer users portals where they can
telephone numbers on the fly, assign multiple "alias" telephone allocate new telephone numbers on the fly, assign multiple "alias"
numbers to a single line service, implement various mobility or find- telephone numbers to a single line service, implement various
me-follow-me applications, and so on. Peer-to-peer telephone mobility or find-me-follow-me applications, and so on. Peer-to-peer
networks have encouraged experiments with distributed databases for telephone networks have encouraged experiments with distributed
telephone number routing and even allocation. databases for telephone number routing and even allocation.
This dynamic control over telephone numbers has few precedents in the This dynamic control over telephone numbers has few precedents in the
traditional PSTN outside of number portability. Number portability traditional PSTN outside of number portability. Number portability
has been implemented in many countries, and the capability of a user allows the capability of a user to choose and change their service
to choose and change their service provider while retaining their TN provider while retaining their TN; it has been implemented in many
is widely implemented now. However, TN administration processes countries; either for all telephony services or for subsets such as
rooted in PSTN technology and policies dictate that this be an mobile. However, TN administration processes rooted in PSTN
exception process fraught with problems and delays. Originally, technology and policies dictate that this be an exception process
processes were built to associate a specific TN to a specific service fraught with problems and delays. Originally, processes were built
provider and never change it. With number portability, the industry to associate a specific TN to a specific service provider and never
had to build new infrastructure, new administrative functions and change it. With number portability, the industry had to build new
processes to change the association of the TN from one service infrastructure, new administrative functions and processes to change
provider to another. Thanks to the increasing sophistication of the association of the TN from one service provider to another.
consumer mobile devices as Internet endpoints as well as telephones, Thanks to the increasing sophistication of consumer mobile devices as
users now associate TNs with many Internet applications other than Internet endpoints as well as telephones, users now associate TNs
telephony. This has generated new interest in models similar to with many Internet applications other than telephony. This has
those in place for administering freephone services in the United generated new interest in models similar to those in place for
States, where a user purchases a number through a sort of number administering freephone services in the United States, where a user
registrar and controls its administration (such as routing) on their purchases a number through a sort of number registrar and controls
own, typically using Internet services to directly make changes to its administration (such as routing) on their own, typically using
the service associated with telephone numbers. Internet services to directly make changes to the service associated
with telephone numbers.
Most TNs today are assigned to specific geographies, at both an Most TNs today are assigned to specific geographies, at both an
international level and within national numbering plans. Numbering international level and within national numbering plans. Numbering
practices today are tightly coupled with the manner that service practices today are tightly coupled with the manner that service
providers interconnect, as well as how TNs are routed and providers interconnect, as well as how TNs are routed and
administered: the PSTN was carefully designed to delegate switching administered: the PSTN was carefully designed to delegate switching
intelligence geographically. In interexchange carrier routing in intelligence geographically. In interexchange carrier routing in
North America, for example, calls to a particular TN are often handed North America, for example, calls to a particular TN are often handed
off to the terminating service provider close to the geography where off to the terminating service provider close to the geography where
that TN is assigned. But the overwhelming success of mobile that TN is assigned. But the overwhelming success of mobile
telephones has increasing eroded the connection between numbers and telephones has increasingly eroded the connection between numbers and
regions. Furthermore, the topology of IP networks is not anchored to regions. Furthermore, the topology of IP networks is not anchored to
geography in the same way that the telephone network is. In an geography in the same way that the telephone network is. In an
Internet environment, establishing a network architecture for routing Internet environment, establishing a network architecture for routing
TNs could depend little on geography. Adapting TNs to the Internet TNs could depend little on geography, relying instead on network
requires more security, richer datasets and more complex query and topologies or other architectural features. Adapting TNs to the
response capabilities than previous efforts have provided. Internet requires more security, richer datasets and more complex
query and response capabilities than previous efforts have provided.
This document will create a common understanding of the problem This document attempts to create a common understanding of the
statement related to allocating, managing, and resolving TNs in an IP problem statement related to allocating, managing, and resolving TNs
environment. It outlines a framework and lists motivating use cases in an IP environment. It outlines a framework and lists motivating
for creating IP-based mechanisms for TNs. It is important to use cases for creating IP-based mechanisms for TNs. It is important
acknowledge at the outset that there are various evolving to acknowledge at the outset that there are various evolving
international and national policies and processes related to TNs, and international and national policies and processes related to TNs, and
any solutions need to be flexible enough to account for variations in any solutions need to be flexible enough to account for variations in
policy and requirements. policy and requirements.
2. Definitions 2. Definitions
This section provides definitions for actors, data types and data This section provides definitions for actors, data types and data
management architectures as they are discussed in this document. management architectures as they are discussed in this document.
Different numbering spaces may instantiate these roles and concepts Different numbering spaces may instantiate these roles and concepts
differently: practices that apply to non-geographic freephone differently: practices that apply to non-geographic freephone
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diverse requirements for telephone number acquisition, management, diverse requirements for telephone number acquisition, management,
and retrieval on the Internet. and retrieval on the Internet.
2.1. Actors 2.1. Actors
The following roles of actors are defined in this document: The following roles of actors are defined in this document:
Numbering Authority: A regulatory body within a country that manages Numbering Authority: A regulatory body within a country that manages
that country's TNs. The Numbering Authority decides national that country's TNs. The Numbering Authority decides national
numbering policy for the nation, region, or other domain for which numbering policy for the nation, region, or other domain for which
it has authority, including what TNs can be allocated, and which it has authority, including what TNs can be allocated, which are
are reserved. reserved, and which entities may obtain TNs.
Registry: An entity that administers the allocation of TNs based on Registry: An entity that administers the allocation of TNs based on
a Numbering Authority's policies. Numbering authorities can act a Numbering Authority's policies. Numbering authorities can act
as the Registries themselves, or they can outsource the function as the Registries themselves, or they can outsource the function
to other entities. There are two subtypes of Registries: an to other entities. Traditional registries are single entities
Authoritative Registry and a Distributed Registry. The general with sole authority and responsibility for specific numbering
term Registry in this document refers to both kinds of Registries. resources, though distributed registries (see Section 2.3) are
also in the scope of this framework.
Authoritative Registry: An authoritative Registry is a single entity
with sole responsibility for specific numbering resources.
Distributed Registry: Distributed Registries are multiple Registries
responsible for the same numbering resources.
Registrar: An entity that distributes the telephone numbers Registrar: An entity that distributes the telephone numbers
administered by a Registry; typically, there are many Registrars administered by a Registry; typically, there are many Registrars
that can distribute numbers from a single Registry, through that can distribute numbers from a single Registry, though
Registrars may serve multiple Registries as well. A Registrar has Registrars may serve multiple Registries as well. A Registrar has
business relationships with its assignees and collects business relationships with number assignees (defined below) and
administrative information from them. collects administrative information from them.
Communication Service Provider (CSP): A provider of communications Communication Service Provider (CSP): A provider of communications
services, where those services can be identified by TNs. This services, where those services can be identified by TNs. This
includes both traditional telephone carriers or enterprises as includes both traditional telephone carriers or enterprises as
well as service providers with no presence on the PSTN who use well as service providers with no presence on the PSTN who use
TNs. This framework does not assume that any single CSP provides TNs. This framework does not assume that any single CSP provides
all the communications service related to a particular TN. all the communications service related to a particular TN.
Service Enabler: An entity that works with CSPs to enable Service Enabler: An entity that works with CSPs to enable
communication service to a User; perhaps a vendor, or third-party communication service to a User; perhaps a vendor, a service
integrator. bureau, or third-party integrator.
User: An individual reachable through a communications service; User: An individual reachable through a communications service;
usually a customer of a communication service provider. usually a customer of a communication service provider.
Government Entity: An entity that, due to legal powers deriving from Government Entity: An entity that, due to legal powers deriving from
national policy, has privileged access to information about number national policy, has privileged access to information about number
administration under certain conditions. administration under certain conditions.
Note that an individual, company or other entity may act in one or Note that an individual, organization, or other entity may act in one
more of the roles above; for example, a company may be a CSP and also or more of the roles above; for example, a company may be a CSP and
a Registrar. Although Numbering Authorities are listed as actors, also a Registrar. Although Numbering Authorities are listed as
they are unlikely to actually participate in the protocol flows actors, they are unlikely to actually participate in the protocol
themselves, though in some situations a Numbering Authority and flows themselves, though in some situations a Numbering Authority and
Registry may be the same administrative entity. Registry may be the same administrative entity.
All actors that are recipients of numbering resources, be they a CSP, All actors that are recipients of numbering resources, be they a CSP,
Service Enabler, or User, can also be said to have a relationship to Service Enabler, or User, can also be said to have a relationship to
a Registry of either an assignee or delegate: a Registry of either an assignee or delegate:
Assignee: An actor that is assigned a TN directly by a Registrar; an Assignee: An actor that is assigned a TN directly by a Registrar; an
assignee always has a direct relationship with a Registrar. assignee always has a direct relationship with a Registrar.
Delegate: An actor that is delegated a TN from an assignee or Delegate: An actor that is delegated a TN from an assignee or
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Figure 1: Chain of Number Assignment Figure 1: Chain of Number Assignment
2.2. Data Types 2.2. Data Types
The following data types are defined in this document: The following data types are defined in this document:
Administrative Data: assignment data related to the TN and the Administrative Data: assignment data related to the TN and the
relevant actors; it includes TN status (assigned, unassigned, relevant actors; it includes TN status (assigned, unassigned,
etc.), contact data for the assignee or delegate, and typically etc.), contact data for the assignee or delegate, and typically
does not require real-time performance as access to this data is does not require real-time access as this data is not required for
not required for ordinary call or session establishment. ordinary call or session establishment.
Service Data: data necessary to enable service for the TN; it Service Data: data necessary to enable service for the TN; it
includes addressing data, service features, and so on, and includes addressing data and service features. Since this data is
typically does require real-time performance, in so far as this necessary to complete calls, it must be obtained in real time.
data typically must be queried during call set-up.
Administrative and service data can fit into three categories: Administrative and service data can fit into three categories:
Public: data that anyone can access, for example a list of which Public: Anyone can access public data. Such data might include a
numbering resources (unallocated number ranges) are available for list of which numbering resources (unallocated number ranges) are
acquisition from the Registry. available for acquisition from the Registry.
Semi-restricted: data that a subset of actors can access, for Semi-restricted: Only a subset of actors can access semi-restricted
example CSPs may be able to access other CSP's service data. data. For example CSPs may be able to access other CSP's service
data.
Restricted: data that is only available to a small subset of actors, Restricted: Only a small subset of actors can access restricted
for example a Government Entity may be able access contact data. For example a Government Entity may be able access contact
information for a User. information for a User.
While it might appear there are really only two categories, public While it might appear there are really only two categories, public
and restricted based on requestor, the distinction between semi- and restricted based on requestor, the distinction between semi-
restricted and restricted is helpful for the use cases below. restricted and restricted is helpful for the use cases below.
2.3. Data Management Architectures 2.3. Data Management Architectures
This framework generally assumes that administrative and service data This framework generally assumes that administrative and service data
is maintained by CSPs, Registrars, and Registries. The role of a is maintained by CSPs, Registrars, and Registries. The terms
Registry described here is a "thin" one, where the Registry manages "registrar" and "registry" are familiar from DNS operations, and
basic allocation information for the numbering space, such as indeed the DNS provides an obvious inspiration for the relationships
information about whether or not the number is assigned, and if between those entities described here. Protocols for transferring
assigned, by which Registrar. It is the Registrar that in turn names between registries and registrars have been standardized in the
manages detailed administrative data about those assignments, such as DNS space for some time (see [14]). Similarly, the division between
contact or billing information for the assignee. In some models, service data acquired by resolving names with the DNS protocol vs.
CSPs and Registrars will be composed (the same administrative administrative data about names acquired through WHOIS [15] is
entity), and in others the Registry and Registrar may similarly be directly analogous to the distinction between service and
composed. Typically, service data resides largely at the CSP itself, administrative data described in Section 2.2. The major difference
though in some models a "thicker" Registry may itself contain a between the data management architecture of the DNS and this
pointer to the servicing CSP for a number or number block. In framework is that the distinction between the CSP and User, due to
addition to traditional centralized Registries, this framework also historical policies of the telephone network, will often not exactly
supports environments where the same data is being managed by correspond to the distinction between a name service and a registrant
in the DNS world - a User in the telephone network is today at least
rarely in a direct relationship with a Registrar comparable to that
of a DNS registrant.
The role of a Registry described here is a "thin" one, where the
Registry manages basic allocation information for the numbering
space, such as information about whether or not the number is
assigned, and if assigned, by which Registrar. It is the Registrar
that in turn manages detailed administrative data about those
assignments, such as contact or billing information for the assignee.
In some models, CSPs and Registrars will be combined (the same
administrative entity), and in others the Registry and Registrar may
similarly be composed. Typically, service data resides largely at
the CSP itself, though in some models a "thicker" Registry may itself
contain a pointer to the servicing CSP for a number or number block.
In addition to traditional centralized Registries, this framework
also supports environments where the same data is being managed by
multiple administrative entities, and stored in many locations. A multiple administrative entities, and stored in many locations. A
distribute registry system is discussed further in [16]. distributed registry system is discussed further in [19]. To support
those use cases, it is important to distinguish the following:
Data store: a service that stores and enables access to Data store: A Data Store is a service that stores and enables access
administrative and/or service data. to administrative and/or service data.
Reference Address: a URL that dereferences to the location of the Reference Address: A Reference Address is a URL that dereferences to
data store. the location of the data store.
Distributed data stores: refers to administrative or service data Distributed data stores: In a Distributed Data Store, administrative
being stored with multiple actors. For example, CSPs could or service data can be stored with multiple actors. For example,
provision their service data to multiple other CSPs. CSPs could provision their service data to multiple other CSPs.
Distributed Registries: refers to multiple Registries managing the Distributed Registries: Multiple Registries can manage the same
same numbering resource. Actors could interact with one or numbering resource. In these architectures, actors could interact
multiple Registries. The Registries would update each other when with one or multiple Registries. The Registries would update each
change occurs. The challenge is to ensure there are no clashes, other when change occurs. The Registries have to ensure that data
e.g., two Registries assigning the same TN to two different remains consistent, e.g. that the same TN is not assigned to two
actors. different actors.
3. Framework 3. Framework
The framework outlined in this document requires three Internet-based The framework outlined in this document requires three Internet-based
mechanisms for managing and resolving telephone numbers (TNs) in an mechanisms for managing and resolving telephone numbers (TNs) in an
IP environment. These mechanisms will likely reuse existing IP environment. These mechanisms will likely reuse existing
protocols for sharing structured data; it is unlikely that new protocols for sharing structured data; it is unlikely that new
protocol development work will be required, though new information protocol development work will be required, though new information
models specific to the data itself will be a major focus of framework models specific to the data itself will be a major focus of framework
development. Likely candidates for reuse here include work done in development. Likely candidates for reuse here include work done in
DRINKS [4] and WEIRDS [12], as well as the TeRI [13] framework. DRINKS [4] and WEIRDS [12], as well as the TeRI [16] framework.
These protocol mechanisms are scoped in a way that makes them likely These protocol mechanisms are scoped in a way that makes them likely
to apply to a broad range of future policies for number to apply to a broad range of future policies for number
administration. It is not the purpose of this framework to dictate administration. It is not the purpose of this framework to dictate
number policy, but instead to provide tools that will work with number policy, but instead to provide tools that will work with
policies as they evolve going forward. These mechanisms therefore do policies as they evolve going forward. These mechanisms therefore do
not assume that number administration is centralized, nor that number not assume that number administration is centralized, nor that number
allocations are restricted to any category of service providers, allocations are restricted to any category of service providers,
though these tools must and will work in environments with those though these tools must and will work in environments with those
properties. properties.
skipping to change at page 9, line 36 skipping to change at page 9, line 50
The three mechanisms are: The three mechanisms are:
Acquisition: a protocol mechanism for acquiring TNs, including an Acquisition: a protocol mechanism for acquiring TNs, including an
enrollment process. enrollment process.
Management: a protocol mechanism for associating data with TNs. Management: a protocol mechanism for associating data with TNs.
Retrieval: a protocol mechanism for retrieving data about TNs. Retrieval: a protocol mechanism for retrieving data about TNs.
The acquisition mechanism will enable actors to acquire TNs for use The acquisition mechanism will enable actors to acquire TNs for use
with a communications service. The acquisition mechanism will with a communications service by requesting numbering resources from
provide a means to request numbering resources from a service a service operated by a Registrar, CSP or similar actor. TNs may be
operated by a Registrar, CSP or similar actor. TNs may be requested requested either on a number-by-number basis, or as inventory blocks.
either on a number-by-number basis, or as inventory blocks. Any
actor who grants numbering resources will retain metadata about the Any actor who grants numbering resources will retain metadata about
assignment, including the responsible organization or individual to the assignment, including the responsible organization or individual
whom numbers have been assigned. to whom numbers have been assigned.
The management mechanism will let actors provision data associated The management mechanism will let actors provision data associated
with TNs. For example, if a User has been assigned a TN, they may with TNs. For example, if a User has been assigned a TN, they may
select a CSP to provide a particular service associated with the TN, select a CSP to provide a particular service associated with the TN,
or a CSP may assign a TN to a User upon service activation. In or a CSP may assign a TN to a User upon service activation. In
either case, a mechanism is needed to provision data associated with either case, a mechanism is needed to provision data associated with
the TN at that CSP. the TN at that CSP, and to extend those data sets as CSPs (and even
Users) require.
The retrieval mechanism will enable actors to learn information about The retrieval mechanism will enable actors to learn information about
TNs, typically by sending a request to a CSP. For some information, TNs. For real-time service data, this typically involves sending a
an actor may need to send a request to a Registry rather than a CSP. request to a CSP; for other information, an actor may need to send a
Different parties may be authorized to receive different information request to a Registry rather than a CSP. Different parties may be
about TNs. authorized to receive different information about TNs.
As an example, a CSP might use the acquisition interface to acquire a As an example, a CSP might use the acquisition interface to acquire a
chunk of numbers from a Registrar. Users might then provision chunk of numbers from a Registrar. Users might then provision
administrative data associated with those numbers at the CSP through administrative data associated with those numbers at the CSP through
the management interface, and query for service data relating to the management interface, and query for service data relating to
those numbers through the retrieval interface of the CSP. those numbers through the retrieval interface of the CSP.
+--------+ +--------+
|Registry| |Registry|
+---+----+ +---+----+
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\ CSP | \ CSP |
+---+---+ +---+---+
A A A A
| | | |
Management | | Retrieval Management | | Retrieval
| | | |
| | | |
+-------++ ++-------+ +-------++ ++-------+
| User | | User | | User | | User |
+--------+ +--------+ +--------+ +--------+
(delegate) (caller)
Figure 2: Example of the Three Interfaces Figure 2: Example of the Three Interfaces
4. Use Cases 4. Use Cases
The high-level use cases in this section will provide an overview of The high-level use cases in this section will provide an overview of
the expected operation of the three interfaces in the MODERN problem the expected operation of the three interfaces in the MODERN problem
space. space:
4.1. Acquisition 4.1. Acquisition
There are various scenarios for how TNs can be acquired by the There are various scenarios for how TNs can be acquired by the
relevant actors: a CSP, Service Enabler, or User. There are three relevant actors, that is, a CSP, Service Enabler, and a User. There
actors from which numbers can be acquired: a Registrar, a CSP and a are three actors from which numbers can be acquired: a Registrar, a
User (presumably one who is delegating to another party). It is CSP and a User (presumably one who is delegating to another party).
assumed that Registrars are either composed with Registries, or that It is assumed that Registrars are either the same entity as
Registrars have established business relationships with Registries Registries, or that Registrars have established business
that enable them to distribute the numbers that the Registries here relationships with Registries that enable them to distribute the
administer. In these use cases, a User may acquire TNs either from a numbers that the Registries administer. In these use cases, a User
CSP or a Registry, or from an intermediate delegate. may acquire TNs either from a CSP or a Registry, or from an
intermediate delegate.
4.1.1. CSP Acquires TNs from Registrar 4.1.1. CSP Acquires TNs from Registrar
The most fundamental and traditional numbering use case is one where The most traditional number acquisition use case is one where a CSP,
a CSP, such as a carrier, requests a block of numbers from a such as a carrier, requests a block of numbers from a Registrar to
Registrar to hold as inventory or assign to customers. hold as inventory or assign to customers.
Through some out-of-band business process, a CSP develops a Through some out-of-band business process, a CSP develops a
relationship with a Registrar. The Registrar maintains a profile of relationship with a Registrar. The Registrar maintains a profile of
the CSP and what qualifications they possess for requesting TNs. The the CSP and assesses whether or not CSPs meet the policy restrictions
CSP may then request TNs from within a specific pool of numbers in for acquiring TNs. The CSP may then request TNs from within a
the authority of the Registry; such as region, mobile, wireline, specific pool of numbers in the authority of the Registry; such as
tollfree, etc. The Registrar must authenticate and authorize the region, mobile, wireline, or freephone. The Registrar must
CSP, and then either grant or deny a request. When an assignment authenticate and authorize the CSP, and then either grant or deny a
occurs, the Registry creates and stores administrative information request. When an assignment occurs, the Registry creates and stores
related to the assignment such as TN status and Registrar contact administrative information related to the assignment such as TN
information, and removes the specific TN(s) from the pool of those status and Registrar contact information, and removes the specific
that are available for assignment. As a part of the acquisition and TN(s) from the pool of those that are available for assignment. As a
assignment process, the Registry provides any necessary credentials part of the acquisition and assignment process, the Registry provides
(for example, STIR certificates [14]) to the Registrar to be used to any necessary credentials (for example, STIR certificates [17]) to
prove the assignment for future transactions. the Registrar to be used to prove the assignment for future
transactions.
Before it is eligible to receive TN assignments, per the policy of a Before it is eligible to receive TN assignments, per the policy of a
national authority, the CSP may need to have submitted (again, national authority, the CSP may need to have submitted (again,
through some out-of-band process) additional qualifying information through some out-of-band process) additional qualifying information
such as current utilization rate or a demand forecast. such as current utilization rate or a demand forecast.
There are two scenarios under which a CSP requests resources; they There are two scenarios under which a CSP requests resources; they
are requesting inventory, or they are requesting for a specific User are requesting inventory, or they are requesting for a specific User
or delegate. TNs assigned to a User are always considered assigned, or delegate. TNs assigned to a User are always considered assigned,
not inventory. The CSP will associate service information for that not inventory. The CSP will associate service information for that
TN, e.g., service address, and make it available to other CSPs to TN, e.g., service address, and make it available to other CSPs to
enable interoperability. The CSP may need to update the Registrar enable interconnection. The CSP may need to update the Registrar
regarding this service activation (this is part of the "TN status" regarding this service activation; this is part of the "TN status"
maintained by the Registrar). maintained by the Registrar.
4.1.2. User Acquires TNs from CSP 4.1.2. User Acquires TNs from CSP
Today, a User typically acquires a TN from CSP when signing up for Today, a User typically acquires a TN from CSP when signing up for
communications service or turning on a new device. In this use case, communications service or turning on a new device. In this use case,
the User becomes the delegate of the CSP. the User becomes the delegate of the CSP.
A User creates or has a relationship with the CSP, and subscribes to A User creates or has a relationship with the CSP, and subscribes to
a communications service which includes the use of a TN. The CSP a communications service which includes the use of a TN. The CSP
collects and stores administrative data about the User. The CSP then collects and stores administrative data about the User. The CSP then
activates the User on their network and creates any necessary service activates the User on their network and creates any necessary service
data to enable interoperability with other CSPs. The CSP could also data to enable connectivity with other CSPs. The CSP could also
update public or privileged databases accessible by other Actors. update public or privileged databases accessible by other Actors.
The CSP provides any necessary credentials to the User (for example, The CSP provides any necessary credentials to the User (for example,
a STIR certificate [14]) to prove the assignment for future a STIR certificate [17]) to prove the assignment for future
transactions. Such credential could be delegated from the one transactions. Such credential could be delegated from the one
provided by the Registrar to the CSP to continue the chain of provided by the Registrar to the CSP to continue the chain of
assignment. assignment.
The CSP could assign a TN from its existing inventory or it could The CSP could assign a TN from its existing inventory or it could
acquire a new TN from the Registrar as part of the assignment acquire a new TN from the Registrar as part of the assignment
process. If it assigns it from its existing inventory it would process. If it assigns it from its existing inventory, it would
remove the specific TN from the pool of those available for remove the specific TN from the pool of those available for
assignment. It may also update the Registrar about the assignment so assignment. It may also update the Registrar about the assignment so
the Registrar has current assignment data. the Registrar has current assignment data.
4.1.3. CSP Delegates TNs to Another CSP 4.1.3. CSP Delegates TNs to Another CSP
A reseller or a service bureau might acquire a block of numbers from A reseller or a service bureau might acquire a block of numbers from
a CSP to be issued to Users. a CSP to be issued to Users.
In this case, the delegate CSP has a business relationship with the In this case, the delegate CSP (as defined in Section 2.1) has a
assignee CSP. The assignee CSP collects and stores administrative business relationship with the assignee CSP. The assignee CSP
data about the delegate. The assignee then activates the delegate on collects and stores administrative data about the delegate. The
their network and creates any necessary service data to enable assignee then activates the delegate on their network and creates any
interoperability with other CSPs. The CSP could also update public necessary service data to enable interconnection with other CSPs.
or privileged databases accessible by other Actors. The CSP provides The CSP could also update public or privileged databases accessible
any necessary credentials to the delegate CSP (for example, a STIR by other Actors. The CSP provides any necessary credentials to the
certificate [14]) to prove the assignment for future transactions. delegate CSP (for example, a STIR certificate [17]) to prove the
Such credentials could be delegated from the one provided by the assignment for future transactions. Such credentials could be
Registry to the CSP to continue the chain of assignment. delegated from the one provided by the Registry to the CSP to
continue the chain of assignment.
The CSP could assign a block from its existing inventory or it could The CSP could assign a block from its existing inventory or it could
acquire new TNs from the Registrar as part of the assignment process. acquire new TNs from the Registrar as part of the assignment process.
If it assigns it from its existing inventory it would remove the If it assigns it from its existing inventory it would remove the
specific TN from the pool of those available for assignment. It may specific TN from the pool of those available for assignment. It may
also update the Registrar about the assignment so the Registrar has also update the Registrar about the assignment so the Registrar has
current assignment data. The Delegate may need to provide current assignment data. The delegate may have the same obligations
utilization and assignment data to the Registry, either directly or to provide utilization data to the Registry as the assignee, per
through the CSP. Section 4.1.1
4.1.4. User Acquires TNs from a Delegate 4.1.4. User Acquires TNs from a Delegate
Acquiring a TN from a delegate follows the process in Section 4.1.2, Acquiring a TN from a delegate follows the process in Section 4.1.2,
as it should be similar to how a User acquires TNs from a CSP. In as it should be similar to how a User acquires TNs from a CSP. But
this case, the delegate re-delegating the TNs would be performing in this case, the delegate re-delegating the TNs would be performing
functions done by the CSP, e.g., providing any credentials, functions done by the CSP, e.g., providing any credentials,
collecting administrative data, creative service data, and so on. collecting administrative data, or creative service data.
4.1.5. User Acquires Numbers from Registrar 4.1.5. User Acquires TNs from Registrar
Today, a user wishing to acquire a freephone number may browse the Today, a user wishing to acquire a freephone number may browse the
existing inventory through one or more Registrars, comparing their existing inventory through one or more Registrars, comparing their
prices and services. Each such Registrar either is a CSP, or has a prices and services. Each such Registrar either is a CSP, or has a
business relationship with a CSP to provide services for that business relationship with one or more CSPs to provide services for
freephone number. that freephone number.
Acquiring a TN from a Registrar follows the process in Section 4.1.1, Acquiring a TN from a Registrar follows the process in Section 4.1.1,
as it should be similar to how a CSP acquires TNs from a Registrar. as it should be similar to how a CSP acquires TNs from a Registrar.
In this case, the User must establish some business relationship In this case, the User must establish some business relationship
directly to a Registrar, similarly to how such functions are directly with a Registrar, similarly to how such functions are
conducted today when Users purchase domain names. For the purpose of conducted today when Users purchase domain names. For the purpose of
status information kept by the Registry, TNs assigned to a User are status information kept by the Registry, TNs assigned to a User are
always considered assigned, not inventory. always considered assigned, not inventory.
In this use case, after receiving a number assignment from the In this use case, after receiving a number assignment from the
Registrar, a User will then obtain communications service from a CSP, Registrar, a User will then obtain communications service from a CSP,
and provide to the CSP the TN to be used for that service. The CSP and provide to the CSP the TN to be used for that service. The CSP
will associate service information for that TN, e.g., service will associate service information for that TN, e.g., service
address, and make it available to other CSPs to enable address, and make it available to other CSPs to enable
interoperability. interconnection. The user will also need to inform the Registrar
about this relationship (see Section 4.2.1.3).
4.2. Management 4.2. Management
The management protocol mechanism is needed to associate The management protocol mechanism is needed to associate
administrative and service data with TNs, and may be used to refresh administrative and service data with TNs, and may be used to refresh
or rollover associated credentials. or rollover associated credentials.
4.2.1. Management of Administrative Data 4.2.1. Management of Administrative Data
Administrative data is primarily related to the status of the TN, its Administrative data is primarily related to the status of the TN, its
administrative contacts, and the actors involved in providing service administrative contacts, and the actors involved in providing service
to the TN. Protocol interactions for administrative data will to the TN. Protocol interactions for administrative data will
therefore predominantly occur between CSPs and Users to the therefore predominantly occur between CSPs and Users to the
Registrar, or between Users and delegate CSPs to the CSP. Registrar, or between Users and delegate CSPs to the CSP.
Most administrative data is not a good candidate for a distributed Some administrative data may be private, and would thus require
data store model. Access to it does not require real-time special handling in a distributed data store model. Access to it
performance therefore local caches are not necessary. And it will does not require real-time performance therefore local caches are not
include sensitive information such as user and contact data. necessary. And it will include sensitive information such as user
and contact data.
Some of the data could lend itself to being publicly available, such Some of the data could lend itself to being publicly available, such
as CSP and TN assignment status. In that case it would be deemed as CSP and TN assignment status. In that case it would be deemed
public information for the purposes of the retrieval interface. public information for the purposes of the retrieval interface.
4.2.1.1. CSP to Registrar 4.2.1.1. CSP to Registrar
After a CSP acquires a TN or block of TNs from the Registrar (per After a CSP acquires a TN or block of TNs from the Registrar (per
Section 4.1.1 above), it then provides administrative data to the Section 4.1.1 above), it then provides administrative data to the
Registrar as a step in the acquisition process. The Registrar will Registrar as a step in the acquisition process. The Registrar will
authenticate the CSP and determine if the CSP is authorized to authenticate the CSP and determine if the CSP is authorized to
provision the administrative data for the TNs in question. The provision the administrative data for the TNs in question. The
Registry will update the status of the TN, i.e., that it is Registry will update the status of the TN, i.e., that it is
unavailable for assignment. The Registrar will also maintain unavailable for assignment. The Registrar will also maintain
administrative data provided by the CSP. administrative data provided by the CSP.
Changes to this administrative data will not be frequent. Examples Changes to this administrative data will not be frequent. Examples
of changes would be terminating service (see Section 4.2.3.2) and of changes would be terminating service (see Section 4.2.3.2),
changing a CSP or delegate. Changes should be authenticated by a changing the name or address of a User or organization, or changing a
credential to prove administrative responsibility for the TN. CSP or delegate. Changes should be authenticated by a credential to
prove administrative responsibility for the TN.
In a distributed Registry model, TN status, e.g., allocated, In a distributed Registry model, TN status, e.g., allocated,
assigned, available, unavailable, would need to be provided to other assigned, available, unavailable, would need to be provided to other
Registries in real-time. Other administrative data could be sent to Registries in real-time. Other administrative data could be sent to
all Registries or other Registries could get a reference address to all Registries or other Registries could get a reference address to
the host Registry's data store. the host Registry's data store.
4.2.1.2. User to CSP 4.2.1.2. User to CSP
After a User acquires a TN or block of TNs from a CSP, the User will After a User acquires a TN or block of TNs from a CSP, the User will
provide administrative data to the CSP. The CSP commonly acts as a provide administrative data to the CSP. The CSP commonly acts as a
Registrar in this case, maintaining the administrative data and only Registrar in this case, maintaining the administrative data and only
notify the Registry of the change in TN status. In this case, the notifies the Registry of the change in TN status. In this case, the
Registry maintains a reference address to the CSP/Registrar's Registry maintains a reference address (see Section 2.3) to the CSP/
administrative data store so relevant actors have the ability to Registrar's administrative data store so relevant actors have the
access the data. Alternatively a CSP could send the administrative ability to access the data. Alternatively, a CSP could send the
data to an external Registrar to store. If there is a delegate administrative data to an external Registrar to store. If there is a
between the CSP and user, they will have to ensure there is a delegate between the CSP and user, they will have to ensure there is
mechanism for the delegate to update the CSP as change occurs. a mechanism for the delegate to update the CSP as change occurs.
4.2.1.3. User to Registrar 4.2.1.3. User to Registrar
If the User has a direct relationship with the Registrar, then If the User has a direct relationship with the Registrar, then
naturally the user could provision administrative data associated naturally the user could provision administrative data associated
with their TN directly to the Registrar. This is the case, for with their TN directly to the Registrar. This is the case, for
example, with the freephone example, where a User has a business example, with the freephone example, where a User has a business
relationship with its freephone provider, and the freephone provider relationship with its freephone provider, and the freephone provider
maintains account and billing data. While delegates necessarily are maintains account and billing data. While delegates may not
not assignees, some environments as an optimization might want to ordinarily have a direct relationship to a Registrar, some
support a model where the delegate updates the Registrar directly on environments as an optimization might want to support a model where
changes, as opposed to sending that data to the CSP or through the the delegate updates the Registrar directly on changes, as opposed to
CSP to the Registrar. As stated already, the protocol should enable sending that data to the CSP or through the CSP to the Registrar. As
Users to acquire TNs directly from a Registrar, which Registrar may stated already, the protocol should enable Users to acquire TNs
or may not also act as a CSP. In these cases the updates would be directly from a Registrar, which Registrar may or may not also act as
similar to that described in Section 4.2.1.1. a CSP. In these cases the updates would be similar to that described
in Section 4.2.1.1.
4.2.2. Management of Service Data 4.2.2. Management of Service Data
Service data is data required by an originating or intermediate CSP Service data is data required by an originating or intermediate CSP
to enable communications service to a User: a SIP URI is an example to enable communications service to a User: a SIP URI is an example
of one service data element commonly used to route communications. of one service data element commonly used to route communications.
CSPs typically create and manage service data, however it is possible CSPs typically create and manage service data, however, it is
that delegates and Users could as well. For most use cases involving possible that delegates and Users could as well. For most use cases
individual Users, it is anticipated that lower-level service involving individual Users, it is anticipated that lower-level
information changes would be communicated to CSPs via existing service information changes (such as an end-user device receiving a
protocols (like the baseline SIP REGISTER [2] method) rather than new IP address) would be communicated to CSPs via existing protocols.
through any new interfaces defined by MODERN. For example, the baseline SIP REGISTER [2] method, even for bulk
operations [13], would likely be used rather than through any new
interfaces defined by MODERN.
4.2.2.1. CSP to other CSPs 4.2.2.1. CSP to other CSPs
After a User enrolls for service with a CSP, in the case where the After a User enrolls for service with a CSP, in the case where the
CSP was assigned the TN by a Registrar, the CSP will then create a CSP was assigned the TN by a Registrar, the CSP will then create a
service address (such as a SIP URI) and associate it with the TN. service address such as a SIP URI and associate it with the TN. The
The CSP needs to update this data to enable service interoperability. CSP needs to update this data to enable service interoperability.
There are multiple ways that this update can occur, though most There are multiple ways that this update can occur, though most
commonly service data is exposed through the retrieval interface (see commonly service data is exposed through the retrieval interface (see
Section 4.3. For certain deployment architectures, like a Section 4.3). For certain deployment architectures, like a
distributed data store model, CSPs may need to provide data directly distributed data store model, CSPs may need to provide data directly
to other CSPs. to other CSPs.
If the CSP is assigning a TN from its own inventory it may not need If the CSP is assigning a TN from its own inventory it may not need
to perform service data updates as change occurs because the existing to perform service data updates as change occurs because the existing
service data associated with inventory may be sufficient once the TN service data associated with inventory may be sufficient once the TN
is put in service. They would however likely update the Registry on is put in service. They would however likely update the Registry on
the change in status. the change in status.
4.2.2.2. User to CSP 4.2.2.2. User to CSP
skipping to change at page 16, line 24 skipping to change at page 17, line 15
4.2.3. Managing Change 4.2.3. Managing Change
This section will address some special use cases that were not This section will address some special use cases that were not
covered in other sections of 4.2. covered in other sections of 4.2.
4.2.3.1. Changing the CSP for an Existing Communications Service 4.2.3.1. Changing the CSP for an Existing Communications Service
A User who subscribes to a communications service, and received their A User who subscribes to a communications service, and received their
TN from that CSP, wishes to retain the same TN but move their service TN from that CSP, wishes to retain the same TN but move their service
to a different CSP. The User provides their credential to the new to a different CSP. The User provides their credential to the new
CSP and the CSP initiates the change in service. CSP and the CSP initiates the change in service
In the simplest scenario, where there's an authoritative composed In the simplest scenario, where there's an authoritative combined
Registry/Registrar that maintains service data, the new CSP provides Registry/Registrar that maintains service data, the new CSP provides
the new service data with the User's credential to the Registry/ the new service data with the User's credential to the Registry/
Registrar, which then makes the change. The old credential is Registrar, which then makes the change. The old credential is
revoked and a new one is provided. The new CSP or the Registrar revoked and a new one is provided. The new CSP or the Registrar
would send a notification to the old CSP, so they can disable would send a notification to the old CSP, so they can disable
service. The old CSP will undo any delegations to the User, service. The old CSP will undo any delegations to the User,
including invalidating any cryptographic credentials (e.g. STIR including invalidating any cryptographic credentials (e.g., STIR
certificates [13]) previously granted to the User. Any service data certificates [13]) previously granted to the User. Any service data
maintained by the CSP must be removed, and similarly, the CSP must maintained by the CSP must be removed, and similarly, the CSP must
delete any such information it provisioned in the Registry. delete any such information it provisioned in the Registry.
In a similar model to common practice in some environments today, the In a similar model to common practice in some environments today, the
User could provide their credential to the old CSP, and the old CSP User could provide their credential to the old CSP, and the old CSP
initiates the change in service. initiates the change in service. Alternatively, a User could go
directly to a Registrar to initiate a port. The framework should
support all of these potential flows.
If there was a distributed Registry that maintained service data, the Note that in cases with a distributed Registry that maintained
Registry would also have to update the other Registries of the service data, the Registry would also have to update the other
change. Registries of the change.
4.2.3.2. Terminating a Service 4.2.3.2. Terminating a Service
A User who subscribes to a communications service, and received their A User who subscribes to a communications service, and received their
TN from the CSP, wishes to terminate their service. At this time, TN from the CSP, wishes to terminate their service. At this time,
the CSP will undo any delegations to the User, including invalidating the CSP will undo any delegations to the User, including invalidating
any cryptographic credentials (e.g. STIR certificates [13]) any cryptographic credentials (e.g., STIR certificates [13])
previously granted to the User. Any service data maintained by the previously granted to the User. Any service data maintained by the
CSP must be removed, and similarly, the CSP must delete any such CSP must be removed, and similarly, the CSP must delete any such
information it provisioned in the Registrar. information it provisioned in the Registrar. However, per the policy
of the Numbering Authority, Registrars and CSPs may be required to
preserve historical data that will be accessible to Government
Entities or others through audits, even if it is no longer
retrievable through service interfaces.
The TN will change state from assigned to unassigned, the CSP will The TN will change state from assigned to unassigned, the CSP will
update the Registry. Depending on policies the TN could go back into update the Registry. Depending on policies the TN could go back into
the Registry, CSP, or delegate's pool of available TNs and would the Registry, CSP, or delegate's pool of available TNs and would
likely enter an ageing process. likely enter an ageing process.
In an alternative use case, a User who received their own TN In an alternative use case, a User who received their own TN
assignment directly from a Registrar terminates their service with a assignment directly from a Registrar terminates their service with a
CSP. At this time, the User might terminate their assignment from CSP. At this time, the User might terminate their assignment from
the Registrar, and return the TN to the Registry for re-assignment. the Registrar, and return the TN to the Registry for re-assignment.
Alternatively, they could retain the TN and elect to assign it to Alternatively, they could retain the TN and elect to assign it to
some other service at a later time. some other service at a later time.
4.3. Retrieval 4.3. Retrieval
Retrieval of administrative or service data will be subject to access Retrieval of administrative or service data will be subject to access
restrictions based on the category of the specific data; public, restrictions based on the category of the specific data: public,
semi-restricted or restricted. Both administrative and service data semi-restricted or restricted. Both administrative and service data
can have data elements that fall into each of these categories. It can have data elements that fall into each of these categories. It
is expected that the majority of administrative and service data will is expected that the majority of administrative and service data will
fall into the semi-restricted category: access to this information fall into the semi-restricted category: access to this information
may require some form of authorization, though service data crucial may require some form of authorization, though service data crucial
to reachability will need to be accessible. In some environments, to reachability will need to be accessible. In some environments,
it's possible that none of the service data will be considered it's possible that none of the service data will be considered
public. public.
The retrieval protocol mechanism for semi-restricted and restricted The retrieval protocol mechanism for semi-restricted and restricted
data needs a way for the receiver of the request to identify the data needs a way for the receiver of the request to identify the
originator of the request and what is being requested. The receiver originator of the request and what is being requested. The receiver
of the request will process that request based on this information. of the request will process that request based on this information.
4.3.1. Retrieval of Public Data 4.3.1. Retrieval of Public Data
Under most circumstances, a CSP wants its communications service to Under most circumstances, a CSP wants its communications service to
be publicly reachable through TNs, so the retrieval interface be publicly reachable through TNs, so the retrieval interface
supports public interfaces that permit clients to query for service supports public interfaces that permit clients to query for service
data about a TN. Some service data may however require that the data about a TN. Some service data may however require that the
client by authorized to receive it, per the use case in Section 4.3.3 client be authorized to receive it, per the use case in Section 4.3.3
below. below.
Public data can simply be posted on websites or made available Public data can simply be posted on websites or made available
through a publicly available API. Public data hosted by a CSP may through a publicly available API. Public data hosted by a CSP may
have a reference address at the Registry. have a reference address at the Registry.
4.3.2. Retrieval of Semi-restricted Administrative Data 4.3.2. Retrieval of Semi-restricted Administrative Data
A CSP is having service problems completing calls to a specific TN, Consider a case in which a CSP is having service problems completing
so it wants to contact the CSP serving that TN. The Registry calls to a specific TN, so it wants to contact the CSP serving that
authorizes the originating CSP to access this information. It TN. The Registry authorizes the originating CSP to access this
initiates a query to the Registry, the Registry verifies the information. It initiates a query to the Registry, the Registry
requestor and the requested data and Registry responds with the verifies the requestor and the requested data and Registry responds
serving CSP and contact data. with the serving CSP and contact data.
Alternatively that information could be part of a distributed data Alternatively that information could be part of a distributed data
store and not stored at the Registry. In that case, the CSP has the store and not stored at the Registry. In that case, the CSP has the
data in a local distributed data store and it initiates the query to data in a local distributed data store and it initiates the query to
the local data store. The local data store responds with the CSP and the local data store. The local data store responds with the CSP and
contact data. No verification is necessary because it was done when contact data. No verification is necessary because it was done when
the CSP was authorized to receive the data store. the CSP was authorized to receive the data store.
4.3.3. Retrieval of Semi-restricted Service Data 4.3.3. Retrieval of Semi-restricted Service Data
A User on a CSP's network calls a TN. The CSP initiates a query for A User on a CSP's network calls a TN. The CSP initiates a query for
service data associated with the TN to complete the call, and will service data associated with the TN to complete the call, and will
receive special service data because the CSP operates in a closed receive special service data because the CSP operates in a closed
environment where different CSPs receive different responses, and environment where different CSPs receive different responses, and
only authorized CSPs may access service data. The query and response only authorized CSPs may access service data. The query and response
must have real-time performance. There are multiple scenarios for must have real-time performance.
the query and response.
In a distributed data store model each CSP distributes its updated In a distributed data store model each CSP distributes its updated
service data to all other CSPs. The originating CSP has the service service data to all other CSPs. The originating CSP has the service
data in its local data store and queries it. The local data store data in its local data store and queries it. The local data store
responds with the service data. The service data can be a reference responds with the service data. The service data in the response can
address to a data store maintained by the serving CSP or it can be be a reference address to a data store maintained by the serving CSP,
the service address itself. In the case where it's a reference or it can be the service address itself. In the case where the
address the query would go to the serving CSP and they would verify response gives a reference address, a subsequent query would go to
the requestor and the requested data and respond. In the case where the serving CSP, who would in turn authorize the requestor for the
it's the service address it would process the call using that. requested data and respond appropriate. In the case where the
original response contains the service address, the requestor would
use that service address as the destination for the call.
In some environments, aspects of the service data may reside at the In some environments, aspects of the service data may reside at the
Registry itself (for example, the assigned CSP for a TN), and thus a Registry itself (for example, the assigned CSP for a TN), and thus
the query may be sent to the Registry. The Registry verifies the the query may be sent to the Registry. The Registry verifies the
requestor and the requested data and responds with the service data, requestor and the requested data and responds with the service data,
such as a SIP URI containing the domain of the assigned CSP. such as a SIP URI containing the domain of the assigned CSP.
4.3.4. Retrieval of Restricted Data 4.3.4. Retrieval of Restricted Data
In this case, a Government Entity wishes to access information about A Government Entity wishes to access information about a particular
a particular User, who subscribes to a communications service. The User, who subscribes to a communications service. The entity that
entity that operates the Registry on behalf of the National Authority operates the Registry on behalf of the National Authority in this
in this case has some pre-defined relationship with the Government case has some pre-defined relationship with the Government Entity.
Entity. When the CSP acquired TNs from the National Authority, it When the CSP acquired TNs from the National Authority, it was a
was a condition of that assignment that the CSP provide access for condition of that assignment that the CSP provide access for
Government Entities to telephone numbering data when certain Government Entities to telephone numbering data when certain
conditions apply. The required data may reside either in the CSP or conditions apply. The required data may reside either in the CSP or
in the Registrar. in the Registrar.
For a case where the CSP delegates a number to the User, the CSP For a case where the CSP delegates a number to the User, the CSP
might provision the Registrar (or itself, if the CSP is composed with might provision the Registrar (or itself, if the CSP is composed with
a Registrar) with information relevant to the User. At such a time a Registrar) with information relevant to the User. At such a time
as the Government Entity needs information about that User, the as the Government Entity needs information about that User, the
Government Entity may contact the Registrar or CSP to acquire the Government Entity may contact the Registrar or CSP to acquire the
necessary data. The interfaces necessary for this will be the same necessary data. The interfaces necessary for this will be the same
as those described in Section 4.3; the Government Entity will be as those described in Section 4.3; the Government Entity will be
authenticated, and an authorization decision will be made by the authenticated, and an authorization decision will be made by the
Registrar or CSP under the policy dictates established by the Registrar or CSP under the policy dictates established by the
National Authority. National Authority.
5. Acknowledgments 5. Acknowledgments
We would like to thank Henning Schulzrinne for his contributions to We would like to thank Henning Schulzrinne and Adam Roach for their
this problem statement and framework, and to thank Pierce Gorman for contributions to this problem statement and framework, and to thank
detailed comments. Pierce Gorman for detailed comments.
6. IANA Considerations 6. IANA Considerations
This memo includes no instructions for the IANA. This memo includes no instructions for the IANA.
7. Security Considerations 7. Security Considerations
The acquisition, management, and retrieval of administrative and The acquisition, management, and retrieval of administrative and
service data associated with telephone numbers raises a number of service data associated with telephone numbers raises a number of
security issues. security issues.
skipping to change at page 21, line 39 skipping to change at page 22, line 33
for the Session Initiation Protocol (SIP) and the Real- for the Session Initiation Protocol (SIP) and the Real-
time Applications and Infrastructure Area", BCP 67, time Applications and Infrastructure Area", BCP 67,
RFC 5727, DOI 10.17487/RFC5727, March 2010, RFC 5727, DOI 10.17487/RFC5727, March 2010,
<http://www.rfc-editor.org/info/rfc5727>. <http://www.rfc-editor.org/info/rfc5727>.
[12] Newton, A. and S. Hollenbeck, "Registration Data Access [12] Newton, A. and S. Hollenbeck, "Registration Data Access
Protocol (RDAP) Query Format", RFC 7482, Protocol (RDAP) Query Format", RFC 7482,
DOI 10.17487/RFC7482, March 2015, DOI 10.17487/RFC7482, March 2015,
<http://www.rfc-editor.org/info/rfc7482>. <http://www.rfc-editor.org/info/rfc7482>.
[13] Peterson, J., "A Framework and Information Model for [13] Roach, A., "Registration for Multiple Phone Numbers in the
Session Initiation Protocol (SIP)", RFC 6140,
DOI 10.17487/RFC6140, March 2011,
<http://www.rfc-editor.org/info/rfc6140>.
[14] Hollenbeck, S., "Generic Registry-Registrar Protocol
Requirements", RFC 3375, DOI 10.17487/RFC3375, September
2002, <http://www.rfc-editor.org/info/rfc3375>.
[15] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
DOI 10.17487/RFC3912, September 2004,
<http://www.rfc-editor.org/info/rfc3912>.
[16] Peterson, J., "An Architecture and Information Model for
Telephone-Related Information (TeRI)", draft-peterson- Telephone-Related Information (TeRI)", draft-peterson-
modern-teri-00 (work in progress), October 2015. modern-teri-02 (work in progress), October 2016.
[14] Peterson, J. and S. Turner, "Secure Telephone Identity [17] Peterson, J. and S. Turner, "Secure Telephone Identity
Credentials: Certificates", draft-ietf-stir- Credentials: Certificates", draft-ietf-stir-
certificates-06 (work in progress), July 2016. certificates-11 (work in progress), October 2016.
[15] Barnes, M., Jennings, C., Rosenberg, J., and M. Petit- [18] Barnes, M., Jennings, C., Rosenberg, J., and M. Petit-
Huguenin, "Verification Involving PSTN Reachability: Huguenin, "Verification Involving PSTN Reachability:
Requirements and Architecture Overview", draft-jennings- Requirements and Architecture Overview", draft-jennings-
vipr-overview-06 (work in progress), December 2013. vipr-overview-06 (work in progress), December 2013.
[16] Bellur, H. and C. Wendt, "Distributed Registry Protocol", [19] Bellur, H. and C. Wendt, "Distributed Registry Protocol",
draft-wendt-modern-drip-00 (work in progress), October draft-wendt-modern-drip-01 (work in progress), July 2016.
2015.
[17] Rosenberg, J. and H. Schulzrinne, "Session Initiation [20] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263, Protocol (SIP): Locating SIP Servers", RFC 3263,
DOI 10.17487/RFC3263, June 2002, DOI 10.17487/RFC3263, June 2002,
<http://www.rfc-editor.org/info/rfc3263>. <http://www.rfc-editor.org/info/rfc3263>.
Authors' Addresses Authors' Addresses
Jon Peterson Jon Peterson
Neustar, Inc. Neustar, Inc.
1800 Sutter St Suite 570 1800 Sutter St Suite 570
Concord, CA 94520 Concord, CA 94520
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