    Internet Engineering Task Force (IETF)             S. Channabasappa, Ed.
    Request for Comments: 6461                                     CableLabs
    Category: Informational                                     January 2012
    ISSN: 2070-1721

           Data for Reachability of Inter-/Intra-NetworK SIP (DRINKS)
                      Use Cases and Protocol Requirements

    Abstract

       This document captures the use cases and associated requirements for
       interfaces that provision session establishment data into Session
       Initiation Protocol (SIP) Service Provider components to assist with
       session routing.  Specifically, this document focuses on the
       provisioning of one such element termed the "registry".

    Status of This Memo

       This document is not an Internet Standards Track specification; it is
       published for informational purposes.

       This document is a product of the Internet Engineering Task Force
       (IETF).  It represents the consensus of the IETF community.  It has
       received public review and has been approved for publication by the
       Internet Engineering Steering Group (IESG).  Not all documents
       approved by the IESG are a candidate for any level of Internet
       Standard; see Section 2 of RFC 5741.

       Information about the current status of this document, any errata,
       and how to provide feedback on it may be obtained at
       http://www.rfc-editor.org/info/rfc6461.

    Copyright Notice

       Copyright (c) 2012 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
       publication of this document.  Please review these documents
       carefully, as they describe your rights and restrictions with respect
       to this document.  Code Components extracted from this document must
       include Simplified BSD License text as described in Section 4.e of
       the Trust Legal Provisions and are provided without warranty as
       described in the Simplified BSD License.

    Channabasappa                 Informational                     [Page 1]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

    Table of Contents

       1. Overview ........................................................2
       2. Terminology .....................................................5
       3. Registry Use Cases ..............................................6
          3.1. Category: Provisioning Mechanisms ..........................6
          3.2. Category: Interconnect Schemes .............................7
          3.3. Category: SED Exchange and Discovery Models ................8
          3.4. Category: SED Record Content ...............................9
          3.5. Category: Separation and Facilitation of Data Management ...9
          3.6. Category: Public Identifiers, TN Ranges, and RNs ..........10
          3.7. Category: Misc ............................................11
       4. Requirements ...................................................11
          4.1. Provisioning Mechanisms ...................................12
          4.2. Interconnect Schemes ......................................12
          4.3. SED Exchange and Discovery Requirements ...................12
          4.4. SED Record Content Requirements ...........................12
          4.5. Data Management Requirements ..............................13
          4.6. Public Identifier, TN Range, and RN Requirements ..........13
          4.7. Misc. Requirements ........................................13
       5. Security Considerations ........................................14
       6. Acknowledgments ................................................14
       7. References .....................................................15
          7.1. Normative References ......................................15
          7.2. Informative References ....................................15

    1.  Overview

       [RFC5486] (Section 3.3) defines Session Establishment Data, or SED,
       as the data used to route a call to the next hop associated with the
       called domain's ingress point.  More specifically, the SED is the set
       of parameters that the outgoing signaling path border elements (SBEs)
       need to establish a session.  However, [RFC5486] does not specify the
       protocol(s) or format(s) to provision SED.  To pave the way to
       specify such a protocol, this document presents the use cases and
       associated requirements that have been proposed to provision SED.

       SED is typically created by the terminating or next-hop SIP service
       provider (SSP) and consumed by the originating SSP.  To avoid a
       multitude of bilateral exchanges, SED is often shared via
       intermediary systems -- termed "registries" within this document.
       Such registries receive data via provisioning transactions from SSPs,
       and then distribute the received data into Local Data Repositories
       (LDRs).  These LDRs are used for call routing by outgoing SBEs.  This
       is depicted in Figure 1.

    Channabasappa                 Informational                     [Page 2]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

                                           *-------------*
                    1. Provision SED       |             |
                  -----------------------> |  Registry   |
                                           |             |
                                           *-------------*
                                                /  \
                                               /    \
                                              /      \
                                             /        \
                                            /          \
                                           /            \
                                          / 2.Distribute \
                                         /      SED       \
                                        V                  V
                                  +----------+       +----------+
                                  |Local Data|       |Local Data|
                                  |Repository|       |Repository|
                                  +----------+       +----------+

                             Figure 1: General Diagram

       In this document, we address the use cases and requirements for
       provisioning registries.  Data distribution to local data
       repositories is out of scope for this document.  The resulting
       provisioning protocol can be used to provision data into a registry
       or between multiple registries operating in parallel.  In Figure 2,
       the case of multiple registries is depicted with dotted lines.

                                      . . . . . . .
                      . . . .  . . .   registry    . . . . . . .
                    .                 . . . . . . .              .
                  .                        .                      .
                 .                         .                       .
                .                          . provision             .
           +-----------+                   .                 +-----------+
           |           |  provision  +----------+  provision |           |
           |   SSP 1   |------------>| Registry |<-----------|   SSP 2   |
           |           |             +----------+            |           |
           |  +-----+  |                   /\                |  +-----+  |
           |  | LDR | <--------------------  ------------------>| LDR |  |
           |  +-----+  |   distribute           distribute   |  +-----+  |
           |           |                                     |           |
           +-----------+                                     +-----------+
                  .                                                .
                   . . . . . . . . . . . . . . . . . . . . . . . .
                                  (provision / distribute)

                           Figure 2: Functional Overview

    Channabasappa                 Informational                     [Page 3]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       In addition, this document proposes two aggregation groups, as
       follows:

       o  Aggregation of public Identifiers into a destination group.

       o  Aggregation of SED records into a route group.

       The use cases in Section 3.5 provide the rationale.  The data model
       depicted in Figure 3 shows the various entities, aggregations, and
       the relationships between them.

           +---------+            +--------------+               +---------+
           |  Data   |0..n    0..n|     Route    | 1         0..n|   SED   |
           |Recipient|------------|     Group    | --------------|  Record |
           +---------+            +--------------+               +---------+
                                         |0..n                        |0..n
                                         |                            |
                                         |                            |
                                         |                            |
                                         |0..n                        |
                                1 +--------------+  0..1              |
                         ---------| Destination  |---------           |
                        |         |    Group     |         |          |
                        |         +--------------+         |          |
                        |                |                 |          |
                        |               1|                 |          |
                        |                |                 |          |
                        |                |                 |          |
                   0..n |           0..n |                 | 0..n     |
                   +---------+      +---------+       +----------+    |
                   |   RN    |      |   TN    |       | Public   |----
                   |         |      |  Range  |       |Identifier| 1
                   +---------+      +---------+       +----------+

                           Figure 3: Data Model Diagram

       The relationships are as described below:

       -  A public identifier object can be directly related to zero or more
          SED Record objects, and a SED Record object can be related to
          exactly one public identifier object.

       -  A destination group object can contain zero or more TN (telephone
          number) Range objects, and a TN Range object can be contained in
          exactly one destination group object.

    Channabasappa                 Informational                     [Page 4]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       -  A destination group object can contain zero or more public
          identifier objects, and a public identifier object can be
          contained in exactly one destination group object.

       -  A destination group object can contain zero or more RN (routing
          number) objects, and an RN object can be contained in exactly one
          destination group object.

       -  A route group object can contain zero or more SED Record objects,
          and a SED Record object can be contained in exactly one route
          group object.

       -  A route group object can be associated with zero or more
          destination group objects, and a destination group object can be
          associated with zero or more route group objects.

       -  A data recipient object can be associated with zero or more route
          group objects, and a route group object can refer to zero or more
          data recipient objects.

    2.  Terminology

       The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
       "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
       document are to be interpreted as described in [RFC2119].

       This document reuses terms from [RFC3261] (e.g., SIP), [RFC5486]
       (e.g., SSP, LUF, LRF, SED) and [RFC5067] (carrier-of-record and
       transit provider).  In addition, this document specifies the
       following additional terms.

       Registry:  The authoritative source for provisioned session
          establishment data (SED) and related information.  A registry can
          be part of an SSP or be an independent entity.

       Registrar:  An entity that provisions and manages data into the
          registry.  An SSP can act as its own registrar or -- additionally
          or alternatively -- delegate this function to a third party (who
          acts as its registrar).

       Local Data Repository (LDR):  The data store component of an
          addressing server that provides resolution responses.

       Public Identifier:  A public identifier refers to a telephone number
          (TN), a SIP address, or other identity as deemed appropriate, such
          as a globally routable URI of a user address (e.g.,
          sip:john.doe@example.net).

    Channabasappa                 Informational                     [Page 5]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       Telephone Number (TN) Range:  A numerically contiguous set of
          telephone numbers.

       Telephone Number (TN) Prefix:  A preceding portion of the digits
          common across a series of E.164 numbers.  A given TN prefix will
          include all the valid E.164 numbers that satisfy the expansion
          rules mandated by the country or the region with which the TNs
          comply.

       Routing Number (RN):  A Routing Number.  For more information, see
          [RFC4694].

       Destination Group:  An aggregation of a set of public identifiers, TN
          Ranges, or RNs that share common SED, which is exposed to a common
          set of peers.

       Data Recipient:  An entity with visibility into a specific set of
          public identifiers (or TN Ranges or RNs), the destination groups
          that contain these public identifiers (or TN Ranges and RNs), and
          a route group's SED records.

       Route Group:  An aggregation that contains a related set of SED
          records and is associated with a set of destination groups.  Route
          groups facilitate the management of SED records for one or more
          data recipients.

    3.  Registry Use Cases

       This section documents use cases related to the provisioning of the
       registry.  Any request to provision, modify, or delete data is
       subject to several security considerations (see Section 5).  The
       protocols that implement these use cases (and associated
       requirements) will need to explicitly identify and address them.

    3.1.  Category: Provisioning Mechanisms

       UC PROV #1  Real-Time Provisioning: Registrars have operational
                   systems that provision public identifiers (or TN Ranges
                   or RNs) in association with their SED.  These systems
                   often function in a manner that expects or requires that
                   these provisioning activities be completed immediately,
                   as opposed to an out-of-band or batch provisioning scheme
                   that can occur at a later time.  This type of
                   provisioning is referred to as "real-time" or "on-demand"
                   provisioning.

    Channabasappa                 Informational                     [Page 6]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       UC PROV #2  Non-Real-Time Bulk Provisioning: Operational systems that
                   provision public identifiers (or TN Ranges or RNs) and
                   associated SED sometimes expect that these provisioning
                   activities be batched up into large sets.  These batched
                   requests are then processed using a provisioning
                   mechanism that is out of band and occurs at a later time.

       UC PROV #3  Multi-Request Provisioning: Regardless of whether or not
                   a provisioning action is performed in real time, SSPs
                   often perform several provisioning actions on several
                   objects in a single request or transaction.  This is done
                   for performance and scalability reasons, and for
                   transactional reasons, such that the set of provisioning
                   actions either fail or succeed atomically, as a complete
                   set.

    3.2.  Category: Interconnect Schemes

       UC INTERCONNECT #1  Inter-SSP SED: SSPs create peering relationships
                           with other SSPs in order to establish
                           interconnects.  Establishing these interconnects
                           involves, among other things, communicating and
                           enabling the points of ingress and other SED used
                           to establish sessions.

       UC INTERCONNECT #2  Direct and Indirect Peering: Some inter-SSP
                           peering relationships are created to enable the
                           establishment of sessions to the public
                           identifiers for which an SSP is the carrier-of-
                           record.  This is referred to as "direct peering".
                           Other inter-SSP peering relationships are created
                           to enable the establishment of sessions to public
                           identifiers for which an SSP is a transit
                           provider.  This is referred to as "indirect
                           peering".  Some SSPs take into consideration an
                           SSP's role as a transit or carrier-of-record
                           provider when selecting a route to a public
                           identifier.

       UC INTERCONNECT #3  Intra-SSP SED: SSPs support the establishment of
                           sessions between their own public identifiers,
                           not just to other SSPs' public identifiers.
                           Enabling this involves, among other things,
                           communicating and enabling intra-SSP signaling
                           points and other SED that can differ from inter-
                           SSP signaling points and SED.

    Channabasappa                 Informational                     [Page 7]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       UC INTERCONNECT #4  Selective Peering (a.k.a. per-peer policies):
                           SSPs create peering relationships with other SSPs
                           in order to establish interconnects.  However,
                           SSP peering relationships often result in
                           different points of ingress or other SED for the
                           same set of public identifiers.  This is referred
                           to as "selective peering" and is done on a route
                           group basis.

       UC INTERCONNECT #5  Provisioning of a delegated hierarchy: An SSP may
                           decide to maintain its own infrastructure to
                           contain the route records that constitute the
                           terminal step in the LUF.  In such cases, the SSP
                           will provision registries to direct queries for
                           the SSP's public identifiers to its own
                           infrastructure rather than provisioning the route
                           records directly.  For example, in the case of
                           DNS-based route records, such a delegated
                           hierarchy would make use of NS and CNAME records,
                           while a flat structure would make use of NAPTR
                           resource records.

    3.3.  Category: SED Exchange and Discovery Models

       UC SED EXCHANGE #1  SED Exchange and Discovery using unified LUF/LRF:
                           When establishing peering relationships, some
                           SSPs may wish to communicate or receive SED
                           (e.g., points of ingress) that constitutes the
                           aggregated result of both LUF and LRF.

       UC SED EXCHANGE #2  SED Exchange and Discovery using LUF's Domain
                           Name: When establishing peering relationships,
                           some SSPs may not wish to communicate or receive
                           points of ingress and other SED using a registry.
                           They only wish to communicate or receive domain
                           names (LUF step only), and then independently
                           resolve those domain names via [RFC3263] to the
                           final points of ingress data (and other SED).

       UC SED EXCHANGE #3  SED Exchange and Discovery using LUF's
                           Administrative Domain Identifier: When
                           establishing peering relationships, some SSPs may
                           not wish to communicate or receive points of
                           ingress and other SED using a registry.  They
                           only wish to communicate or receive an
                           administrative domain identifier, which is not
                           necessarily resolvable via DNS.  The subsequent
                           process of using that administrative domain

    Channabasappa                 Informational                     [Page 8]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

                           identifier to select points of ingress or other
                           SED can be SSP specific and is out of scope for
                           this document.

       UC SED EXCHANGE #4  Coexistent SED Exchange and Discovery Models:
                           When supporting multiple peering relationships,
                           some SSPs have the need to concurrently support
                           all three of the SED Exchange and Discovery
                           Models already described in this section
                           (Section 3.3) for the same set of public
                           identifiers.

    3.4.  Category: SED Record Content

       UC SED RECORD #1  SED Record Content: Establishing interconnects
                         between SSPs involves, among other things,
                         communicating points of ingress, the service types
                         (SIP, SIPS, etc.) supported by each point of
                         ingress, and the relative priority of each point of
                         ingress for each service type.

       UC SED RECORD #2  Time-To-Live (TTL): For performance reasons,
                         querying SSPs sometimes cache SED that had been
                         previously looked up for a given public identifier.
                         In order to accomplish this, SSPs sometimes specify
                         the TTL associated with a given SED record.

    3.5.  Category: Separation and Facilitation of Data Management

       UC DATA #1  Separation of Provisioning Responsibility: An SSP's
                   operational practices often separate the responsibility
                   of provisioning the points of ingress and other SED from
                   the responsibility of provisioning public identifiers (or
                   TN Ranges or RNs).  For example, a network engineer can
                   establish a physical interconnect with a peering SSP's
                   network and provision the associated domain name, host,
                   and IP addressing information.  Separately, for each new
                   subscriber, the SSP's provisioning systems provision the
                   associated public identifiers.

       UC DATA #2  Destination Groups: SSPs often provision identical SED
                   for large numbers of public identifiers (or TN Ranges or
                   RNs).  For reasons of efficiency, groups of public
                   identifiers that have the same SED can be aggregated.
                   These aggregations are known as destination groups.  The
                   SED is then indirectly associated with destination groups
                   rather than with each individual public identifier (or TN
                   Ranges or RNs).

    Channabasappa                 Informational                     [Page 9]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       UC DATA #3  Route Groups: SSPs often provision identical SED for
                   large numbers of public identifiers (or TN Ranges or
                   RNs), and then expose that relationship between a group
                   of SED records and a group of public identifiers (or TN
                   Ranges or RNs) to one or more SSPs.  This combined
                   grouping of SED records and destination groups
                   facilitates efficient management of relationships and the
                   list of peers (data recipients) that can look up public
                   identifiers and receive the associated SED.  This dual
                   set of SED records and destination groups is termed a
                   "route group".

    3.6.  Category: Public Identifiers, TN Ranges, and RNs

       UC PI #1  Additions and Deletions: SSPs often allocate and de-
                 allocate specific public identifiers to and from end-users.
                 This involves, among other things, activating or
                 deactivating specific public identifiers (TN Ranges or
                 RNs), and directly or indirectly associating them with the
                 appropriate points of ingress and other SED.

       UC PI #2  Carrier-of-Record versus Transit Provisioning: Some inter-
                 SSP peering relationships are created to enable the
                 establishment of sessions to the public identifiers (or TN
                 Ranges or RNs) for which an SSP is the carrier-of-record.
                 Other inter-SSP peering relationships are created to enable
                 the establishment of sessions for which an SSP is a transit
                 provider.  Some SSPs take into consideration an SSP's role
                 as a transit or carrier-of-record provider when selecting a
                 route.

       UC PI #3  Multiplicity: As described in previous use cases, SSPs
                 provision public identifiers (or TN Ranges or RNs) and
                 their associated SED for multiple peering SSPs, and as both
                 the carrier-of-record and transit provider.  As a result, a
                 given public identifier (or TN Range or RN) key can reside
                 in multiple destination groups at any given time.

       UC PI #4  Destination Group Modification: SSPs often change the SED
                 associated with a given public identifier (or TN Range or
                 RN).  This involves, among other things, directly or
                 indirectly associating them with a different point of
                 ingress, different services, or different SED.

       UC PI #5  Carrier-of-Record versus Transit Modification: SSPs may
                 have the need to change their carrier-of-record versus
                 transit role for public identifiers (or TN Ranges or RNs)
                 that they previously provisioned.

    Channabasappa                 Informational                    [Page 10]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       UC PI #6  Modification of Authority: An SSP indicates that it is the
                 carrier-of-record for an existing public identifier or TN
                 Range.  If the public identifier or TN Range were
                 previously associated with a different carrier-of-record,
                 then there are multiple possible outcomes, such as a) the
                 previous carrier-of-record is disassociated, b) the
                 previous carrier-of-record is relegated to transit status,
                 or c) the new carrier-of-record is placed in inactive mode.
                 The choice may be dependent on the deployment scenario and
                 is out of scope for this document.

    3.7.  Category: Misc

       UC MISC #1  Number Portability: The SSP wishes to provide, in query
                   response to public identifiers, an associated routing
                   number (RN).  This is the case where a set of public
                   identifiers is no longer associated with the original SSP
                   but has been ported to a recipient SSP, who provides
                   access to these identifiers via a switch on the Signaling
                   System Number 7 network identified by the RN.

       UC MISC #2  Data Recipient Offer and Accept: When a peering
                   relationship is established (or invalidated), SSPs
                   provision (or remove) data recipients in the registry.
                   However, a peer may first need to accept its role (as a
                   data recipient) before such a change is made effective.
                   Alternatively, an auto-accept feature can be configured
                   for a given data recipient.

       UC MISC #3  Open Numbering Plans: In several countries, an open
                   numbering plan is used, where the carrier-of-record is
                   only aware of a portion of the E.164 number (i.e., the TN
                   prefix).  The carrier-of-record may not know the complete
                   number or the number of digits in the number.  The rest
                   of the digits are handled offline (e.g., by a Private
                   Branch Exchange, or PBX).  For example, an SSP can be the
                   carrier-of-record for "+123456789" and be the carrier-of-
                   record for every possible expansion of that number, such
                   as "+12345678901" and "+123456789012", even though the
                   SSP does not know what those expansions could be.  This
                   can be described as the carrier-of-record effectively
                   being authoritative for the TN prefix.

    4.  Requirements

       This section lists the requirements extracted from the use cases in
       Section 3.  The objective is to make it easier for protocol designers
       to understand the underlying requirements and to reference and list

    Channabasappa                 Informational                    [Page 11]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

       the requirements that they support (or not).  The requirements listed
       here, unless explicitly indicated otherwise, are expected to be
       supported.  Protocol proposals are also expected to indicate their
       compliance with these requirements and highlight ones that they don't
       meet (if any).  Furthermore, the requirements listed here are not
       meant to be limiting, i.e., protocol implementations and deployments
       may choose to support additional requirements based on use cases that
       are not listed in this document.

    4.1.  Provisioning Mechanisms

       REQ-PROV-1:  Real-time provisioning.

       REQ-PROV-2:  (Optional) Non-real-time bulk provisioning.

       REQ-PROV-3:  Multi-request provisioning.

    4.2.  Interconnect Schemes

       REQ-INTERCONNECT-1:  Inter-SSP peering.

       REQ-INTERCONNECT-2:  Direct and Indirect peering.

       REQ-INTERCONNECT-3:  Intra-SSP SED.

       REQ-INTERCONNECT-4:  Selective peering.

       REQ-INTERCONNECT-5:  Provisioning of a delegated hierarchy.

    4.3.  SED Exchange and Discovery Requirements

       REQ-SED-1:  SED containing unified LUF and LRF content.

       REQ-SED-2:  SED containing LUF-only data using domain names.

       REQ-SED-3:  SED containing LUF-only data using administrative
                   domains.

       REQ-SED-4:  Support for all the other REQ-SED requirements (listed in
                   this section), concurrently, for the same public
                   identifier (or TN Range or RN).

    4.4.  SED Record Content Requirements

       REQ-SED-RECORD-1:  Ability to provision SED record content.

       REQ-SED-RECORD-2:  (Optional) Communication of an associated TTL for
                          a SED Record.

    Channabasappa                 Informational                    [Page 12]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

    4.5.  Data Management Requirements

       REQ-DATA-MGMT-1:  Separation of responsibility for the provisioning
                         the points of ingress and other SED, from the
                         responsibility of provisioning public identifiers.

       REQ-DATA-MGMT-2:  Ability to aggregate a set of public identifiers as
                         destination groups.

       REQ-DATA-MGMT-3:  Ability to create the aggregation termed route
                         group.

    4.6.  Public Identifier, TN Range, and RN Requirements

       REQ-PI-TNR-RN-1:  Provisioning of, and modifications to, the
                         following aggregations: destination group and route
                         groups.

       REQ-PI-TNR-RN-2:  Ability to distinguish an SSP as either the
                         carrier-of-record provider or the transit provider.

       REQ-PI-TNR-RN-3:  A given public identifier (or TN Range or RN) can
                         reside in multiple destination groups at the same
                         time.

       REQ-PI-TNR-RN-4:  Modification of public identifier (or TN Range or
                         RN) by allowing them to be moved to a different
                         destination group via an atomic operation.

       REQ-PI-TNR-RN-5:  SSPs can indicate a change to their role from
                         carrier-of-record provider to transit, or vice
                         versa.

       REQ-PI-TNR-RN-6:  Support for modification of authority with the
                         conditions described in UC PI #6.

    4.7.  Misc. Requirements

       REQ-MISC-1:  Number portability support.

       REQ-MISC-2:  Ability for the SSP to be offered a peering relationship
                    and for the SSP to accept (explicitly or implicitly) or
                    reject such an offer.

       REQ-MISC-3:  Support for open numbering plans.

    Channabasappa                 Informational                    [Page 13]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

    5.  Security Considerations

       Session establishment data allows for the routing of SIP sessions
       within, and between, SIP Service Providers.  Access to this data can
       compromise the routing of sessions and expose a SIP Service Provider
       to attacks such as service hijacking and denial of service.  The data
       can be compromised by vulnerable functional components and interfaces
       identified within the use cases.

       A provisioning framework or protocol that implements the described
       use cases MUST, therefore, provide data confidentiality and message
       integrity.  Such frameworks and protocols MUST specify mechanisms to
       authenticate and authorize any entity that provisions data into the
       registry, i.e., that the entity is who it says it is and is allowed
       to use the provisioning interface.  The determination of whether such
       an entity is authorized to provision specific data elements (e.g., a
       certain public identifier or TN Range) -- while REQUIRED -- may be
       left to local policy.

    6.  Acknowledgments

       This document is a result of various contributions from (and
       discussions within) the IETF DRINKS Working Group; specifically, in
       alphabetical order: Alexander Mayrhofer, Deborah A Guyton, Gregory
       Schumacher, Jean-Francois Mule, Kenneth Cartwright, Manjul Maharishi,
       Penn Pfautz, Ray Bellis, Richard Shockey, and Syed Ali.

       The editor also wishes to thank the following for their comments and
       suggestions: Otmar Lendl, Sohel Khan, Peter Koch, Brian Rosen, Jon
       Peterson, Gonzalo Camarillo, and Stephen Farrell.

    Channabasappa                 Informational                    [Page 14]

    RFC 6461            DRINKS Use Cases and Requirements       January 2012

    7.  References

    7.1.  Normative References

       [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.

       [RFC5486]  Malas, D. and D. Meyer, "Session Peering for Multimedia
                  Interconnect (SPEERMINT) Terminology", RFC 5486,
                  March 2009.

    7.2.  Informative References

       [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
                  A., Peterson, J., Sparks, R., Handley, M., and E.
                  Schooler, "SIP: Session Initiation Protocol", RFC 3261,
                  June 2002.

       [RFC3263]  Rosenberg, J. and H. Schulzrinne, "Session Initiation
                  Protocol (SIP): Locating SIP Servers", RFC 3263,
                  June 2002.

       [RFC4694]  Yu, J., "Number Portability Parameters for the "tel" URI",
                  RFC 4694, October 2006.

       [RFC5067]  Lind, S. and P. Pfautz, "Infrastructure ENUM
                  Requirements", RFC 5067, November 2007.

    Author's Address

       Sumanth Channabasappa (editor)
       CableLabs
       858 Coal Creek Circle
       Louisville, CO  80027
       USA

       EMail: sumanth@cablelabs.com

    Channabasappa                 Informational                    [Page 15]