One document matched: draft-peterson-modern-problems-02.txt
Differences from draft-peterson-modern-problems-01.txt
Network Working Group J. Peterson
Internet-Draft T. McGarry
Intended status: Informational NeuStar, Inc.
Expires: April 21, 2016 October 19, 2015
Modern Problem Statement, Use Cases, and Framework
draft-peterson-modern-problems-02.txt
Abstract
The functions of the public switched telephone network (PSTN) are
rapidly migrating to the Internet. This is generating new
requirements for many traditional elements of the PSTN, including
telephone numbers (TNs). TNs no longer serve simply as telephone
routing addresses, they are now identifiers which may be used by
Internet-based services for a variety of purposes including session
establishment, identity verification, and service enablement. This
problem statement examines how the existing tools for allocating and
managing telephone numbers do not align with the use cases of the
Internet environment, and proposes a framework for Internet-based
services relying on TNs.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 21, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
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Table of Contents
1. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Actors . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Data Management Architectures . . . . . . . . . . . . . . 6
3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Acquisition . . . . . . . . . . . . . . . . . . . . . . . 8
4.1.1. CSP Acquires TNs from Registry . . . . . . . . . . . 8
4.1.2. User Acquires TNs from CSP . . . . . . . . . . . . . 9
4.1.3. CSP Delegates TNs to Another CSP . . . . . . . . . . 9
4.1.4. User Acquires TNs from a Delegate . . . . . . . . . . 10
4.1.5. User Acquires Numbers from Registry . . . . . . . . . 10
4.2. Management . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.1. Management of Administrative Data . . . . . . . . . . 11
4.2.1.1. CSP to Registry . . . . . . . . . . . . . . . . . 11
4.2.1.2. User to CSP . . . . . . . . . . . . . . . . . . . 11
4.2.2. Management of Service Data . . . . . . . . . . . . . 12
4.2.2.1. CSP to other CSPs . . . . . . . . . . . . . . . . 12
4.2.2.2. User to CSP . . . . . . . . . . . . . . . . . . . 12
4.2.2.3. User to Registry . . . . . . . . . . . . . . . . 12
4.2.3. Managing Change . . . . . . . . . . . . . . . . . . . 13
4.2.3.1. Changing the CSP for an Existing Communications
Service . . . . . . . . . . . . . . . . . . . . . 13
4.2.3.2. Terminating a Service . . . . . . . . . . . . . . 13
4.3. Retrieval . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3.1. Retrieval of Public Data . . . . . . . . . . . . . . 14
4.3.2. Retrieval of Semi-restricted Administrative Data . . 14
4.3.3. Retrieval of Semi-restricted Service Data . . . . . . 15
4.3.4. Retrieval of Restricted Data . . . . . . . . . . . . 15
5. Distributed Registries and Data Stores . . . . . . . . . . . 16
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9. Informative References . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Problem Statement
The challenges of utilizing telephone numbers (TNs) on the Internet
have been known for some time. Internet telephony provided the main
use case for routing telephone numbers on the Internet in a manner
similar to how calls are routed in the public switched telephone
network (PSTN). As the Internet had no service for discovering the
endpoints associated with telephone numbers, ENUM [3] created a DNS-
based mechanism for resolving TNs in an IP environment, by defining
procedures for translating TNs into URIs for use by protocols such as
SIP [2]. Originally, it was envisioned that ENUM would be deployed
as a global hierarchical service, though in practice, it has only
been deployed piecemeal by various parties. Most notably, ENUM is
used as an internal network function, and is hardly used between
service provider networks. The original ENUM concept of a single
root, e164.arpa, proved to be politically challenging, and less
centralized models have thus flourished.
Subsequently, the DRINKS [4] framework showed ways that authorities
might provision information about TNs at an ENUM service or similar
Internet-based directory. These technologies have generally tried to
preserve the features and architecture familiar from the PSTN
numbering environment.
Telephone numbering, however, has long been transitioning away from a
provider-centric model towards a user-centric model. Number
portability has been implemented in many countries, and the right of
a user to choose and change their service provider while retaining
their TN is widely acknowledged now. However, TN administration
processes rooted in PSTN technology and policies dictate that this be
an exception process fraught with problems and delays. Thanks to the
increasing sophistication of consumer mobile devices, users now
associate TNs with many applications other than telephony. Ideally
the user would have full control of their TN and would drive the
porting process on their own rather than rely on complex and time
consuming back office processes among multiple service providers.
Most TNs today are assigned to specific geographies, at both an
international level and within national numbering plans. This has
shaped the way that service providers interconnect, as well as how
TNs are routed and administered: the PSTN was carefully designed to
delegate switching intelligence geographically. In interexchange
carrier routing in North America, for example, calls to a particular
TN are often handed off to the terminating service provider close to
the geography where that TN is assigned. But the overwhelming
success of mobile telephones has increasing eroded the connection
between numbers and regions. Furthermore, the topology of IP
networks is not anchored to geography in the same way that the
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telephone network is. In an Internet environment, establishing a
network architecture for routing TNs would depend little on
geography. Adapting TNs to the Internet requires more security,
richer datasets and more complex query and response capabilities than
previous efforts have provided.
With the PSTN well on its way to transitioning to an all IP network,
and TNs showing no signs of sunsetting as a resource, it is time to
address the issues of routing, management and administration of TNs
in an IP environment. This document will create a common
understanding of the problem statement related to TNs in an IP
environment and help develop a vision for how to create IP-based
mechanisms for TNs. It will be important to acknowledge that there
are various international and national policies and processes related
to TNs, and any solutions need to be flexible enough to account for
these variations.
2. Definitions
This section provides definitions for actors, data types and data
management architectures as they are discussed in this document.
2.1. Actors
The following actors are defined in this document:
Numbering Authority: A regulatory body within a country that manages
that country's TNs. The Numbering Authority decides national
numbering policy, including what TNs can be allocated, and which
are reserved.
Registry: An entity that administers the allocation of TNs based on
a Numbering Authority's policies. Numbering authorities can act
as the Registries themselves, or they can outsource the function
to other entities. There are two types of Registries an
authoritative Registry and a distributed Registry. An
authoritative Registry is a single entity with sole responsibility
for specific numbering resources. Distributed Registries are
multiple Registries responsible for the same numbering
resources.(There's more on distributed Registries later in this
section.) The general term Registry in this document refers to
both kinds of Registries. When referring to one versus the other
this document will use the specific term.
Communication Service Provider (CSP): A provider of communications
services to Users, where those services can be identified by TNs.
This includes both traditional telephone carriers or enterprises
as well as service providers with no presence on the PSTN who use
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TNs. This framework does not assume that any single CSP provides
all the communications service related to a TN.
Service Enabler: An entity that works with CSPs to enable
communication service to a User; perhaps a vendor, or third-party
integrator.
User: An individual reachable through a communications service;
usually a customer of a communication service provider who uses
TNs to reach and identify services. Sophisticated users may also
act as their own CSPs.
Government Entity: An entity that, due to legal powers deriving from
national policy, has privileged access to information about number
administration under certain conditions.
Note that a given entity may act in one or more of the roles above.
An entity acting as a CSP, Service Enabler, or User can also be said
to have a relationship to the Registry of either an assignee or
delegate:
Assignee: An entity that is assigned a TN by the Registry. There is
always a direct relationship between the Registry and the
assignee.
Delegate: An entity that is delegated a TN from an assignee or
another delegate. Delegates may use a TN for a communications
service or delegate it in turn.
Note that although Numbering Authorities are listed as actors, they
are unlikely to actually participate in the protocol flows
themselves.
2.2. Data Types
The following data types are defined in this document:
Administrative Data: assignment data related to the TN and the
relevant actors; it includes TN status, contact data for the
assignee or delegate, etc. and typically does not require real-
time performance.
Service Data: data necessary to enable service for the TN; it
includes addressing data, feature capabilities, etc. and typically
does require real-time performance.
Administrative and service data can fit into three categories:
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Public: data that anyone can access, for example a list of which
numbering resources are available for acquisition from the
Registry.
Semi-restricted: data that a somewhat broad subset of actors can
access, 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,
for example a Government Entity may be able access contact
information for a User.
While it seems there are really only two categories, public and
restricted based on requestor, the distinction between semi-
restricted and restricted is helpful for the use cases below.
2.3. Data Management Architectures
Beyond traditional centralized Registries, this framework also
supports environments where the same data is being managed by
multiple entities, and stored in many locations.
Data store: a service that stores and enables access to
administrative and/or service data. Typically Registries and CSPs
would manage data stores.
Reference Address: a URL that dereferences to the location of the
data store.
Distributed data stores: refers to administrative or service data
being stored with multiple actors. For example, CSPs could
provision their service data to multiple other CSPs.
Distributed Registries: refers to multiple Registries managing the
same numbering resource. Actors could interact with one or
multiple Registries. The Registries would update each other when
change occurs. The challenge is to ensure there are no clashes,
e.g., two Registries assigning the same TN to two different
actors.
3. Framework
The framework outlined in this document requires three Internet-based
mechanisms for managing and resolving TNs (TNs) in an IP environment.
These mechanisms will likely reuse existing protocols for sharing
structured data; it is unlikely that new protocol development work
will be required, though new information models specific to the data
itself will be a major focus of framework development. Likely
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candidates for reuse here include work done in DRINKS and WEIRDS, as
well as the TeRQ [12] framework.
These protocol mechanisms are scoped in a way that makes them likely
to apply to a broad range of future policies for number
administration. It is not the purpose of this framework to dictate
number policy, but instead to provide tools that will work with
policies as they evolve going forward. These mechanisms therefore do
not assume that number administration is centralized, nor that number
"ownership" is restricted to any privileged service providers, though
these tools must and will work in environments with those properties.
The three mechanisms are:
Acquisition: a protocol mechanism for acquiring TNs, including an
enrollment process.
Management: a protocol mechanism for associating data with TNs.
Retrieval: a protocol mechanism for retrieving data about TNs from
either an authority or a CSP.
The acquisition mechanism will enable actors to acquire TNs for use
with a communications service. The acquisition mechanism will
provide a means to request numbering resources from a service
operated by a Registry, CSP or similar actor. TNs may be requested
either on a number-by-number basis, or as inventory blocks. Any
actor who grants numbering resources will retain metadata about the
assignment, including the responsible organization or individual to
whom numbers have been assigned.
The management mechanism will let actors provision data associated
with TNs at CSPs. For example, if a User has been assigned a TN,
they may 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 either case, a mechanism is needed to provision data associated
with the TN at that CSP.
The retrieval mechanism will enable actors to learn information about
TNs, typically by sending a request to a CSP. For some information,
an actor may need to send a request to a Registry rather than a CSP.
Different parties may be authorized to receive different information
about TNs.
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4. Use Cases
The high-level use cases in this section will provide an overview of
the expected operation of the three interfaces in the MODERN problem
space.
4.1. Acquisition
There are various scenarios for how TNs can be acquired by the
relevant actors: a Registry, CSP, Service Enabler, or User. There
are three actors from which numbers can be acquired: a Registry, a
CSP and a User (presumably one who is delegating to another party).
In these use cases, a User may acquire TNs either from a CSP or a
Registry, or from an intermediate delegate.
4.1.1. CSP Acquires TNs from Registry
The most fundamental and traditional numbering use case is one where
a CSP, such as a carrier, requests a block of numbers from a Registry
to hold as inventory or assign to customers.
Through some out-of-band business process, a CSP develops a
relationship with a Registry. The Registry maintains a profile of
the CSP and what qualifications they possess for requesting TNs. The
CSP may then request TNs from within a specific pool of numbers in
the authority of the Registry; such as region, mobile, wireline,
tollfree, etc. The Registry must authenticate and authorize the CSP,
and then either grant or deny a request. When an assignment occurs,
the Registry creates and stores administrative information related to
the assignment such as TN status and contact information, and removes
the specific TN(s) from the pool of those that are available for
assignment. As a part of the acqusition and assignment process, the
Registry provides credentials (for example, STIR certificates [13])
to the CSP to be used to prove the assignment for future
transactions.
Before it is eligible to receive TN assignments, per the policy of a
national authority, the CSP may need to have submitted (again,
through some out-of-band process) additional qualifying information
such as current utilization rate or a demand forecast.
There are two scenarios under which a CSP requests resources; they
are requesting inventory, or they are requesting for a specific User
or delegate. TNs assigned to a User are always considered assigned
by the Registry, not inventory. In this use case, after receiving a
number assignment from the Registry, a User will then obtain
communications service from a CSP, and provide to the CSP the TN to
be used for that service along with the credential. The CSP will
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associate service information for that TN, e.g., service address, and
make it available to other CSPs to enable interoperability. The CSP
may need to update the Registry regarding this service activation
(this is part of the "TN status" maintained by the Registry).
4.1.2. User Acquires TNs from CSP
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,
the User becomes the delegate of the CSP.
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
collects and stores administrative data about the User. The CSP then
activates the User on their network and creates any necessary service
data to enable interoperability with other CSPs. The CSP could also
update public or privileged databases accessible by other Actors.
The CSP provides a credential to the User (for example, a STIR
certificate [13]) to prove the assignment for future transactions.
The credential could be delegated from the one provided by the
Registry to the CSP to continue the chain of assignment.
The CSP could assign a TN from its existing inventory or it could
acquire a new TN from the Registry as part of the assignment process.
If it assigns it from its existing inventory it would remove the
specific TN from the pool of those available for assignment. It may
also update the Registry about the assignment so the Registry has
current assignment data.
4.1.3. CSP Delegates TNs to Another CSP
A reseller or a service bureau might acquire a block of numbers from
a CSP to be issued to Users.
In this case, the delegate CSP has a business relationship with the
assignee CSP. The assignee CSP collects and stores administrative
data about the delegate. The assignee then activates the delegate on
their network and creates any necessary service data to enable
interoperability with other CSPs. The CSP could also update public
or privileged databases accessible by other Actors. The CSP provides
a credential to the delegate CSP (for example, a STIR certificate
[13]) to prove the assignment for future transactions. The
credential could be 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
acquire new TNs from the Registry as part of the assignment process.
If it assigns it from its existing inventory it would remove the
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specific TN from the pool of those available for assignment. It may
also update the Registry about the assignment so the Registry has
current assignment data. The Delegate may need to provide
utilization and assignment data to the Registry, either directly or
through the CSP.
4.1.4. User Acquires TNs from a Delegate
Aquiring a TN from another delegate follows the process in
Section 4.1.2, as it should be similar to how a User acquires TNs
from a CSP. In this case, the delegate re-delegating the TNs would
be performing functions done by the CSP, e.g., providing credentials,
collecting administrative data, creative service data, and so on.
4.1.5. User Acquires Numbers from Registry
Today, typically Users do not have the capability to request
numbering resources directly from a Registry. MODERN supports this
use case, for those Numbering Authorities and Registries that might
establish policies enabling this use case in the future.
Acquiring a TN from a Registry follows the process in Section 4.1.1,
as it should be similar to how a CSP acquires TNs from a Registry.
In this case, the User must establish some business relationship
directly to a Registry, perhaps similarly to how such functions are
conducted today when Users purchase domain names. For the purpose of
status information kept by the Registry, TNs assigned to a User are
always considered assigned, not inventory.
In this use case, after receiving a number assignment from the
Registry, 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
will associate service information for that TN, e.g., service
address, and make it available to other CSPs to enable
interoperability.
4.2. Management
The management protocol mechanism is needed to associate
administrative and service data with TNs and distribute and receive
credentials. While some similar use cases may apply to individual
Users, it is anticipated that for the most part these lower-level
service information changes would be communicated via existing
protocols (like the baseline [2] SIP REGISTER method) rather than
through any interfaces defined by MODERN.
While some similar use cases may apply to individual Users, it is
anticipated that for the most part these lower-level service
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information changes would be communicated via existing protocols
(like the baseline [2] SIP REGISTER method) rather than through any
interfaces defined by MODERN.
4.2.1. Management of Administrative Data
Administrative data primarily is related to the status of the TN and
the actors involved in providing service to the TN. The Registry and
CSP will most likely maintain the data. Protocol interactions will
therefore predominantly occur between CSPs and Users to the Registry,
or between Users and delegate CSPs to the CSP.
Most administrative data is not a good candidate for a distributed
data store model. Access to it does not require real-time
performance therefore local caches are not 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
as CSP and TN assignment status. In that case the CSP or Registry
could simply expose it on a web application.
4.2.1.1. CSP to Registry
A CSP acquires a TN or block of TNs from the Registry (per
Section 4.1.1 above) and provides administrative data to the Registry
during the acquisition process. The Registry will update the status
of the TN, i.e., that it is unavailable for assignment. The Registry
will also maintain administrative data provided by the CSP. Changes
to this data will not be frequent. Examples of changes would be
terminating service and changing a CSP or delegate. Changes should
be accompanied by the credential to prove administrative
responsibility for the TN.
In a distributed Registry model, TN status, e.g., allocated,
assigned, available, unavailable, would need to be provided to other
Registries in real-time. Other administrative data could be sent to
all Registries or other Registries could get a reference address to
the host Registry's data store.
4.2.1.2. User to CSP
The User acquires a TN or block of TNs from a CSP and provides
administrative data, the CSP provides a credential. The CSP could
maintain the data and only notify the Registry of the change in TN
status. In this case, the Registry may maintain a reference address
to the CSP's administrative data store so relevant actors have the
ability to access the data. Alternatively they could send the data
to the Registry to store. If there is a delegate between the CSP and
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user, they will have to ensure there is a mechanism for the delegate
to update the CSP as change occurs.
4.2.2. Management of Service Data
Service data is data necessary to enable communications service to
the delegate or User, for example a SIP URI. CSPs typically create
and manage service data, however it is possible that delegates and
Users could as well.
4.2.2.1. CSP to other CSPs
After a User enrolls for service with a CSP, in the case where the
CSP was assigned the TN by a Registry, the CSP will then create a
service address (such as a SIP URI) and associate it with the TN.
The CSP needs to update this data to enable service interoperability.
There are multiple ways that this update can occur, though most
commonly service data is exposed through the retrieval interface (see
Section 4.3. For certain deployment architectures, like a
distributed data store model, CSPs may need to provide data directly
to other CSPs.
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
service data associated with inventory may be sufficient once the TN
is put in service. They would however likely update the Registry on
the change in status.
4.2.2.2. User to CSP
Users could also associate service data to their TNs at the CSP. An
example is a User acquires a TN from the Registry (as described in
Section 4.1.5) and wants to provide that TN to the CSP so the CSP can
enable service. In this case, once the user provides the number to
the CSP, the CSP would update the Registry or other actors as
outlined in 4.2.2.1.
4.2.2.3. User to Registry
If the User has a direct relationship with the Registry, then
naturally the user could could provision administrative data
associated with their TN directly to the Registry. While delegates
necessarily are not assignees, there could be a model where the
delegate updates the Registry directly on changes, as opposed to
sending that data to the CSP or through the CSP to the Registry. As
stated already the protocol should enable Users to acquire TNs
directly from a Registry and in essence act as their own CSP. In
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these cases the updates would be similar to that described in
4.2.2.1.
4.2.3. Managing Change
This section will address some special use cases that were not
covered in other sections of 4.2.
4.2.3.1. Changing the CSP for an Existing Communications Service
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
to a different CSP. The User provides their credential to the new
CSP and the CSP initiates the change in service.
In the simplest scenario, where there's an authoritative Registry
that maintains service data, the new CSP provides the new service
data with the User's credential to the Registry and the Registry
makes the change. The old credential is revoked and a new one is
provided. The new CSP or Registry would send a notification to the
old CSP, so they can disable service. The old CSP will undo any
delegations to the User, including invalidating any cryptographic
credentials (e.g. STIR certificates [13]) previously granted to the
User. Any service data maintained by the CSP must be removed, and
similarly, the CSP must delete any such information it provisioned in
the Registry.
If there was a distributed Registry that maintained service data, the
Registry would also have to update the other Registries of the
change.
If there was a distributed data store the new CSP would have to
update all the other CSPs including the old CSP of the new service
data. In this model both CSPs would have to have the ability to
update all of the same CSPs. That is the new CSP would have to make
sure all of the CSPs provisioned by the old CSP get the updated
service data.
[TBD - more on the case where multiple CSPs provide services for a
given TN, and only one service is "ported" to a new CSP?]
4.2.3.2. Terminating a Service
A User who subscribes to a communications service, and received their
TN from the CSP, wishes to terminate their service. At this time,
the CSP will undo any delegations to the User, including invalidating
any cryptographic credentials (e.g. STIR certificates [13])
previously granted to the User. Any service data maintained by the
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CSP must be removed, and similarly, the CSP must delete any such
information it provisioned in the Registry.
The TN will change state from assigned to unassigned, the CSP will
update the Registry. Depending on policies the TN could go back into
the Registry, CSP, or delegate's pool of available TNs and would
likely enter an aging process.
In an alternative use case, a User who received their own TN
assignment directly from the Registry terminates their service with a
CSP. At this time, the User might terminate their assignment from
the Registry, and return the TN to the Registry for re-assignment.
Alternatively, they could retain the TN and elect to assign it to
some other service at a later time.
4.3. Retrieval
Retrieval of administrative or service data will be subject to access
restrictions based on the category of the specific data; public,
semi-restricted or restricted. Both administrative and service data
can have data elements that fall into each of these categories. It
is expected that the majority of administrative and service data will
fall into the semi-restricted category. It's possible that none of
the service data will be considered public.
The retrieval protocol mechanism for semi-restricted and restricted
data needs a way for the receiver of the request to identify the
originator of the request and what is being requested. The receiver
of the request will process that request based on this information.
4.3.1. Retrieval of Public Data
Under most circumstances, a CSP wants its communications service to
be publicly reachable through TNs, so the retrieval interface
supports public interfaces that permit clients to query for service
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
below.
Public data can simply be posted on websites or made available
through a publicly available API. Public data hosted by a CSP may
have a reference address at the Registry.
4.3.2. Retrieval of Semi-restricted Administrative Data
A CSP is having service problems completing calls to a specific TN,
so it wants to contact the CSP serving that TN. The Registry
authorizes the originating CSP to access to this information. It
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initiates a query to the Registry, the Registry verifies the
requestor and the requested data and Registry responds with the
serving CSP and contact 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
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
contact data. No verification is necessary because it was done when
the CSP was authorized to receive the data store.
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
service data associated with the TN to complete the call, and will
receive special service data because the CSP operates in a closed
environment where different CSPs receive different responses, and
only authorized CSPs may access service data. The query and response
must have real-time performance. There are multiple scenarios to for
the query and response.
In a distributed data store model each CSP distributes its updated
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
responds with the service data. The service data can be a reference
address to a data store maintained by the serving CSP or it can be
the service address itself. In the case where it's a reference
address the query would go to the serving CSP and they would verify
the requestor and the requested data and respond. In the case where
it's the service address it would process the call using that.
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
the query may be sent to the Registry. The Registry verifies the
requestor and the requested data and responds with the service data,
such as a SIP URI containing the domain of the assigned CSP.
4.3.4. Retrieval of Restricted Data
In this case, a Government Entity wishes to access information about
a particular User, who subscribes to a communications service. The
entity that operates the Registry on behalf of the National Authority
in this case has some pre-defined relationship with the Government
Entity. When the CSP acquired TNs from the National Authority, it
was a condition of that assignment that the CSP provide access for
Government Entities to telephone numbering data when certain
conditions apply. The required data may reside either in the CSP or
in the Registry.
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For a case where the CSP delegates a number to the User, the CSP
might provision the Registry with information relevant to the User.
At such a time as the Government Entity needs information about that
User, the Government Entity may contact the Registry or CSP to
acquire the necessary data. The interfaces necessary for this will
be the same as those described in Section 4.3; the Government Entity
will be authenticated, and an authorization decision will be made by
the Registry or CSP under the policy dictates established by the
National Authority.
5. Distributed Registries and Data Stores
It is possible to create a distributed Registry or distributed Data
Stores for the administrative and service information associated with
a TN.
In a distributed Registry there would be multiple duplicate copies of
the Registry data. A CSP or User would interact with one Registry
and that Registry would be responsible for initiating updates to all
other Registries when there is a change. The challenge is to ensure
that there are no clashes, e.g., two Registries assigning the same TN
to two different CSPs.
Similarly multiple entities can maintain duplicate copies of
administrative and service data associated with TNs. For example,
when a CSP enables service for a User they can initiative an update
of the service address to multiple other data stores managed by other
service providers. This may not be the best solution for User
contact data.
[More TBD]
6. Acknowledgments
We would like to thank Henning Schulzrinne for his contributions to
this problem statement and framework.
7. IANA Considerations
This memo includes no request to IANA.
8. Security Considerations
TBD.
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9. Informative References
[1] Peterson, J. and C. Jennings, "Enhancements for
Authenticated Identity Management in the Session
Initiation Protocol (SIP)", RFC 4474,
DOI 10.17487/RFC4474, August 2006,
<http://www.rfc-editor.org/info/rfc4474>.
[2] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>.
[3] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to
Uniform Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)", RFC 6116,
DOI 10.17487/RFC6116, March 2011,
<http://www.rfc-editor.org/info/rfc6116>.
[4] Channabasappa, S., Ed., "Data for Reachability of Inter-
/Intra-NetworK SIP (DRINKS) Use Cases and Protocol
Requirements", RFC 6461, DOI 10.17487/RFC6461, January
2012, <http://www.rfc-editor.org/info/rfc6461>.
[5] Watson, M., "Short Term Requirements for Network Asserted
Identity", RFC 3324, DOI 10.17487/RFC3324, November 2002,
<http://www.rfc-editor.org/info/rfc3324>.
[6] Jennings, C., Peterson, J., and M. Watson, "Private
Extensions to the Session Initiation Protocol (SIP) for
Asserted Identity within Trusted Networks", RFC 3325,
DOI 10.17487/RFC3325, November 2002,
<http://www.rfc-editor.org/info/rfc3325>.
[7] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
2012, <http://www.rfc-editor.org/info/rfc6698>.
[8] Elwell, J., "Connected Identity in the Session Initiation
Protocol (SIP)", RFC 4916, DOI 10.17487/RFC4916, June
2007, <http://www.rfc-editor.org/info/rfc4916>.
[9] Schulzrinne, H., "The tel URI for Telephone Numbers",
RFC 3966, DOI 10.17487/RFC3966, December 2004,
<http://www.rfc-editor.org/info/rfc3966>.
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[10] Rosenberg, J. and C. Jennings, "The Session Initiation
Protocol (SIP) and Spam", RFC 5039, DOI 10.17487/RFC5039,
January 2008, <http://www.rfc-editor.org/info/rfc5039>.
[11] Peterson, J., Jennings, C., and R. Sparks, "Change Process
for the Session Initiation Protocol (SIP) and the Real-
time Applications and Infrastructure Area", BCP 67,
RFC 5727, DOI 10.17487/RFC5727, March 2010,
<http://www.rfc-editor.org/info/rfc5727>.
[12] Peterson, J., "A Framework and Information Model for
Telephone-Related Queries (TeRQ)", draft-peterson-terq-04
(work in progress), July 2015.
[13] Peterson, J., "Secure Telephone Identity Credentials:
Certificates", draft-ietf-stir-certificates-02 (work in
progress), July 2015.
[14] Barnes, M., Jennings, C., Rosenberg, J., and M. Petit-
Huguenin, "Verification Involving PSTN Reachability:
Requirements and Architecture Overview", draft-jennings-
vipr-overview-06 (work in progress), December 2013.
[15] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263,
DOI 10.17487/RFC3263, June 2002,
<http://www.rfc-editor.org/info/rfc3263>.
Authors' Addresses
Jon Peterson
Neustar, Inc.
1800 Sutter St Suite 570
Concord, CA 94520
US
Email: jon.peterson@neustar.biz
Tom McGarry
Neustar, Inc.
1800 Sutter St Suite 570
Concord, CA 94520
US
Email: tom.mcgarry@neustar.biz
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