Network Working Group                                      J. Livingood
Request for Comments: 5278                 Comcast Cable Communications
Category: Standards Track                                 D. Troshynski
                                                           Acme Packet
                                                             July 2008


   IANA Registration of Enumservices for Voice and Video Messaging

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Abstract

  This document registers the Enumservice named "vmsg", which is used
  to facilitate the real-time routing of voice, video, and unified
  communications to a messaging system.  This vmsg Enumservice
  registers three Enumservice types: "voicemsg", "videomsg", and
  "unifmsg".  Each type also registers the subtypes "sip", "sips",
  "http", and "https", as well as the subtype "tel" for the "voicemsg"
  type.

























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Table of Contents

  1. Introduction ....................................................3
     1.1. Selected Use Cases for Illustrative Purposes ...............4
     1.2. Consideration of Other Existing Enumservices ...............5
  2. Distribution of Data ............................................5
  3. Security Considerations .........................................5
  4. ENUM Service Registration for voicemsg ..........................6
     4.1. Registration for "voicemsg" with Subtype "sip" .............6
     4.2. Registration for "voicemsg" with Subtype "sips" ............7
     4.3. Registration for "voicemsg" with Subtype "tel" .............7
     4.4. Registration for "voicemsg" with Subtype "http" ............8
     4.5. Registration for "voicemsg" with Subtype "https" ...........9
  5. ENUM Service Registration for videomsg .........................10
     5.1. Registration for "videomsg" with Subtype "sip" ............10
     5.2. Registration for "videomsg" with Subtype "sips" ...........10
     5.3. Registration for "videomsg" with Subtype "http" ...........11
     5.4. Registration for "videomsg" with Subtype "https" ..........12
  6. ENUM Service Registration for unifmsg ..........................13
     6.1. Registration for "unifmsg" with Subtype "sip" .............13
     6.2. Registration for "unifmsg" with Subtype "sips" ............13
     6.3. Registration for "unifmsg" with Subtype "http" ............14
     6.4. Registration for "unifmsg" with Subtype "https" ...........15
  7. Selected Examples for Illustrative Purposes ....................16
     7.1. Example Using a 'sip' URI .................................16
     7.2. Example Using a 'tel' URI .................................16
     7.3. Example Using a Backreference .............................16
     7.4. Example Using a 'sip' URI without a Telephone Number ......17
     7.5. Example of Failover Using E2U+videomsg:sip ................17
  8. Implementation Recommendations .................................17
     8.1. Call Processing When Multiple Records Are Returned ........17
     8.2. NAPTR Configuration Issues ................................18
  9. IANA Considerations ............................................18
  10. Acknowledgements ..............................................18
  11. Contributors ..................................................19
  12. References ....................................................19
     12.1. Normative References .....................................19
     12.2. Informative References ...................................20













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1.  Introduction

  ENUM (E.164 Number Mapping, RFC 3761 [1]) is a technology that
  transforms E.164 numbers (the International Public Telecommunication
  Numbering Plan, ITU-T Recommendation E.164 [2]) into domain names and
  then uses DNS (Domain Name System, RFC 1034 [3]) delegation through
  NS records and Naming Authority Pointer (NAPTR) records (Dynamic
  Delegation Discovery System (DDDS) Part Three: The Domain Name System
  (DNS) Database, RFC 3403 [4]) to look up what services are available
  for a specific domain name.

  This document registers Enumservices according to the guidelines
  given in RFC 3761 [1] to be used for provisioning in the services
  field of a NAPTR [4] resource record to indicate the types of
  functionality associated with an end point and/or telephone number.
  The registration is defined within the DDDS (Dynamic Delegation
  Discovery System [4][5][6][7][8]) hierarchy, for use with the "E2U"
  DDDS Application defined in RFC 3761.

  Voice messaging systems are used widely with telephony and voice
  communication services.  The need for a voice messaging service type
  has become clear in order to provide certain applications with direct
  access to various voice messaging services (for example, voicemail),
  most typically via the use of SIP.

  The authors considered the use of Voice Profile for Internet Mail
  (VPIM) [14] but found that VPIM was best suited to the non-real-time
  and non-session-based routing of a voice message once it had been
  deposited into a voice messaging system.  Thus, VPIM was a good
  solution for the non-real-time and non-session-based routing of voice
  messages between and within domains, but it did not enable real-time
  interaction with a voice messaging system.

  Thus, a need has been identified for this voice messaging service
  type that would enable, for example, some of the use cases listed in
  this section.

  Video messaging systems, sometimes called visual voice messaging
  systems, are beginning to be used with real-time communication
  services.  The need for a video messaging service type has become
  clear in order to provide certain applications with direct access to
  various video messaging services, most typically via the use of SIP.
  Thus, a need has been identified for this video messaging service
  type that would enable, for example, some of the use cases listed in
  this section.






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  Finally, several service providers and software developers have
  indicated that their system for voice messaging and video messaging
  either have been or soon will be unified into a single system.  As
  such, they desired to have the option of using an Enumservice type
  that represents a subscriber's mailbox as being a so-called unified
  messaging repository.  Thus, a need has been identified for this
  unified voice and video messaging service type that would enable, for
  example, some of the use cases listed in this section.

1.1.  Selected Use Cases for Illustrative Purposes

  The following is a partial, non-exclusive list of use cases that the
  vmsg Enumservice could address:

  * A called party is busy or does not answer a call.  A client or
    server then determines that a messaging service should be used and
    sends the calling party's session to such a service.  The client or
    server needs to be able to determine which server to direct this
    real-time session to, whether that is within or outside of the
    called party's domain.

  * Similar to the above use case, a real-time session is attempted to
    a messaging system, but that system is currently unavailable.
    Since multiple service type records may be returned by the original
    ENUM query, the client or server could then attempt to initiate a
    session with one or more backup messaging servers in a manner that
    is transparent to the calling party and that supports better
    overall availability of a messaging service.

  * Similar to the above use case, this service type could be used to
    balance load across multiple messaging servers, whether those are
    in the same or in different physical locations.

  * A user with an account on a messaging service needs to connect to
    the messaging service in order to retrieve messages.  They initiate
    a real-time session, and an ENUM query is performed to discover the
    messaging server that holds its mailbox.

  * In the process of invoking and supporting a real-time, automated
    and interactive session with a user, whether for message deposit or
    retrieval, VoiceXML files are referenced and utilized, via either
    HTTP or HTTPS.  Multiple VoiceXML servers could be associated with
    a user and returned via ENUM query, for the purposes of load
    balancing, for example.







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1.2.  Consideration of Other Existing Enumservices

  The authors considered whether this service type could simply use the
  SIP Enumservice type [19], but found that it does not satisfy their
  voice messaging requirements, particularly given the non-SIP URI sub-
  types specified herein.  Even with sub-types for SIP URIs, however,
  there are challenges to using the SIP Enumservice type.  For example,
  a request for access to such a service could be extended to the
  requesting SIP client, or User Agent Client (UAC), rather than
  relying upon the local policy of a SIP server, or User Agent Server
  (UAS), which means that special routing logic within a UAS cannot be
  relied upon to solve this problem.  More importantly, however, the
  authors have found that without this service type, a UAC or UAS will
  be presented with multiple SIP URIs, with no ability other than in
  non-standards-based routing rules or application logic to recognize
  which one is related to a voice messaging, video messaging, or
  unified voice and video messaging service.

2.  Distribution of Data

  The authors believe that it is more likely that these records will be
  distributed on a purely private basis, but they may also be
  distributed in public ENUM trees.  Distribution of this NAPTR data
  could be either (a) on a private basis within a service provider's
  internal network, (b) on a private basis between one or more parties
  using a variety of security mechanisms to prohibit general public
  access, or (c) openly available.

3.  Security Considerations

  DNS, as used by ENUM, is a global, distributed database.  Should
  implementers of this specification use e164.arpa or any other
  publicly available domain as the tree for maintaining voicemsg
  Enumservice data, this information would be visible to anyone
  anonymously.  While this is not qualitatively different from
  publication in a Telephone Directory, it does open or ease access to
  such data without any indication that such data has been accessed or
  by whom it has been accessed.

  Such data harvesting by third parties is often used to generate lists
  of targets for unsolicited information.  Thus, a third party could
  use this to generate a list that it can use to make unsolicited
  telemarketing phone calls, or so-called SPAM over Internet Telephony
  (SPIT).  Many countries have do-not-call registries or other legal or
  regulatory mechanisms in place to deal with such abuses.






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  As noted earlier, carriers, service providers, and other users may
  simply choose not to publish such information in the public e164.arpa
  tree, but may instead simply publish this in their internal ENUM
  routing database that is only able to be queried by trusted elements
  of their network and/or partner networks, such as softswitches and
  SIP proxy servers.  They may also choose to publish such information
  in a carrier-only branch of the e164.arpa tree, should one be
  created.

  Although an E.164 telephone number does not appear to reveal as much
  identity information about a user as a name in the format
  sip:username@hostname or email:username@hostname, the information is
  still publicly available; thus, there is still the risk of unwanted
  communication.

  An analysis of threats specific to the dependence of ENUM on the DNS
  and the applicability of DNSSEC [16] to this is provided in RFC 3761
  [1].  A thorough analysis of threats to the DNS itself is covered in
  RFC 3833 [17].

4.  ENUM Service Registration for voicemsg

4.1.  Registration for "voicemsg" with Subtype "sip"

  Enumservice Name: "voicemsg"

  Enumservice Type: "voicemsg"

  Enumservice Subtypes: "sip"

  URI Schemes: 'sip:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a voice
  communication session to a voice messaging system.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])





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  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

4.2.  Registration for "voicemsg" with Subtype "sips"

  Enumservice Name: "voicemsg"

  Enumservice Type: "voicemsg"

  Enumservice Subtypes: "sips"

  URI Schemes: 'sips:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a voice
  communication session to a voice messaging system.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

4.3.  Registration for "voicemsg" with Subtype "tel"

  Enumservice Name: "voicemsg"

  Enumservice Type: "voicemsg"

  Enumservice Subtype: "tel"

  URI Schemes: 'tel:'







Livingood & Troshynski      Standards Track                     [Page 7]

RFC 5278                    VMSG Enumservice                   July 2008


  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a voice
  communication session to a voice messaging system.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

4.4.  Registration for "voicemsg" with Subtype "http"

  Enumservice Name: "voicemsg"

  Enumservice Type: "voicemsg"

  Enumservice Subtype: "http"

  URI Schemes: 'http:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'http:' [11] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even voice message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON





Livingood & Troshynski      Standards Track                     [Page 8]

RFC 5278                    VMSG Enumservice                   July 2008


  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

4.5.  Registration for "voicemsg" with Subtype "https"

  Enumservice Name: "voicemsg"

  Enumservice Type: "voicemsg"

  Enumservice Subtype: "https"

  URI Schemes: 'https:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information,
  which can be contacted using TLS or the Secure Socket Layer protocol.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'https:' [12] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even voice message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.




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RFC 5278                    VMSG Enumservice                   July 2008


5.  ENUM Service Registration for videomsg

5.1.  Registration for "videomsg" with Subtype "sip"

  Enumservice Name: "videomsg"

  Enumservice Type: "videomsg"

  Enumservice Subtypes: "sip"

  URI Schemes: 'sip:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a video
  communication session to a video messaging system.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

5.2.  Registration for "videomsg" with Subtype "sips"

  Enumservice Name: "videomsg"

  Enumservice Type: "videomsg"

  Enumservice Subtypes: "sips"

  URI Schemes: 'sips:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a video
  communication session to a video messaging system.




Livingood & Troshynski      Standards Track                    [Page 10]

RFC 5278                    VMSG Enumservice                   July 2008


  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

5.3.  Registration for "videomsg" with Subtype "http"

  Enumservice Name: "videomsg"

  Enumservice Type: "videomsg"

  Enumservice Subtype: "http"

  URI Schemes: 'http:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'http:' [11] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even video message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])






Livingood & Troshynski      Standards Track                    [Page 11]

RFC 5278                    VMSG Enumservice                   July 2008


  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

5.4.  Registration for "videomsg" with Subtype "https"

  Enumservice Name: "videomsg"

  Enumservice Type: "videomsg"

  Enumservice Subtype: "https"

  URI Schemes: 'https:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information,
  which can be contacted using TLS or the Secure Socket Layer protocol.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'https:' [12] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even video message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.









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6.  ENUM Service Registration for unifmsg

6.1.  Registration for "unifmsg" with Subtype "sip"

  Enumservice Name: "unifmsg"

  Enumservice Type: "unifmsg"

  Enumservice Subtypes: "sip"

  URI Schemes: 'sip:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a unified
  communication session to a unified messaging system.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

6.2.  Registration for "unifmsg" with Subtype "sips"

  Enumservice Name: "unifmsg"

  Enumservice Type: "unifmsg"

  Enumservice Subtypes: "sips"

  URI Schemes: 'sips:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified can be
  addressed by the associated URI scheme in order to initiate a unified
  communication session to a unified messaging system.




Livingood & Troshynski      Standards Track                    [Page 13]

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  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

6.3.  Registration for "unifmsg" with Subtype "http"

  Enumservice Name: "unifmsg"

  Enumservice Type: "unifmsg"

  Enumservice Subtype: "http"

  URI Schemes: 'http:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'http:' [11] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even video message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])






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  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.

6.4.  Registration for "unifmsg" with Subtype "https"

  Enumservice Name: "unifmsg"

  Enumservice Type: "unifmsg"

  Enumservice Subtype: "https"

  URI Schemes: 'https:'

  Functional Specification:

  This Enumservice indicates that the remote resource identified by the
  associated URI scheme is capable of being a source of information,
  which can be contacted using TLS or the Secure Socket Layer protocol.

  Note that the kind of information retrieved can be manifold. Usually,
  contacting a resource by an 'https:' [12] URI provides a document.
  This document can contain references that will trigger the download
  of many different kinds of information, such as text, audio, video,
  executable code, or even video message files.  Thus, one cannot be
  more specific about the kind of information expected when contacting
  the resource.

  Security Considerations: See Section 3.

  Intended Usage: COMMON

  Authors:

  Jason Livingood ([email protected])
  Don Troshynski ([email protected])

  Any other information the author deems interesting:

  Implementers should review a non-exclusive list of examples below in
  Section 7.









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7.  Selected Examples for Illustrative Purposes

  The following sub-sections document several examples that
  implementers may find informative.  These examples shall in no way
  limit the various forms that this Enumservice may take.

7.1.  Example Using a 'sip' URI

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 100 "u" "E2U+voicemsg:sip"
        "!^.*$!sip:[email protected]!".

  In this example, a calling party has attempted a session that has
  gone unanswered after a certain period of time.  The calling party's
  session is sent to the appropriate voice messaging server, a
  personalized greeting is played to the calling party, after which it
  records a voice message to the called party.

7.2.  Example Using a 'tel' URI

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 100 "u" "E2U+voicemsg:tel"
        "!^.*$!tel:1-215-555-0123!".

  In this example, a calling party has attempted a session that has
  gone unanswered after a certain period of time.  The calling party's
  session is sent to the appropriate voice messaging server, a
  personalized greeting is played to the calling party, after which it
  records a voice message to the called party.

7.3.  Example Using a Backreference

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 100 "u" "E2U+voicemsg:sip"
        "!(^.*)$!sip:\[email protected]!".

  In this example, a backreference is used to reduce the size of the
  NAPTR record.  The sip URI uses "\1", which would dynamically replace
  the expression with the TN, in this case +12155550123.












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RFC 5278                    VMSG Enumservice                   July 2008


7.4.  Example Using a 'sip' URI without a Telephone Number

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 100 "u" "E2U+voicemsg:sip"
        "!^.*$!sip:[email protected]!".

  In this example, a calling party has attempted a session that has
  gone unanswered after a certain period of time.  The calling party's
  session is sent to the appropriate voice messaging server, a
  personalized greeting is played to the calling party, after which it
  records a voice message to the called party.  The URI that this
  session is directed to does not include a telephone number, as this
  user has multiple service that are not particularly tied to telephone
  numbers whereby text, audio, video and other multimedia messages can
  be received and accessed.

7.5.  Example of Failover Using E2U+videomsg:sip

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 100 "u" "E2U+videomsg:sip"
        "!^.*$!sip:[email protected]!".

     $ORIGIN 3.2.1.0.5.5.5.5.1.2.1.e164.arpa.
        NAPTR 10 200 "u" "E2U+videomsg:sip"
        "!^.*$!sip:[email protected]!".

  In this example, the preference indicates that gw1.example.com is
  used first (100), and if this is unreachable, then the next higher
  preference (200) is used and gw2.example.com is contacted.  While out
  of scope for this document, a service provider could thus mirror or
  cluster a message store and fail from the primary to secondary using
  the DNS in an active-standby mode.

8.  Implementation Recommendations

8.1.  Call Processing When Multiple Records Are Returned

  It is likely that both E2U+sip and E2U+voicemsg, E2U+videomsg, and/or
  E2U+unifmsg Enumservice type records will be returned for a given
  query.  In this case, this could result in what is essentially
  E2U+sip records for real-time communications with an end user, while,
  for example, the E2U+voicemsg records will be used for real-time
  communications with a voice messaging service, when the called party
  is not available or does not wish to be disturbed.  Therefore, the
  network element that receives the results of this ENUM query will
  need to know enough information in order to select the voicemsg
  service type, rather than the sip service type.




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  In addition, it is likely that multiple E2U+voicemsg, E2U+videomsg,
  and/or E2U+unifmsg Enumservice type records will be returned for a
  given query.  In this case, multiple records may include order and
  preference to allow recursion or load balancing.  Order could be used
  to designate a primary and a backup voice, video, or unified voice
  and video messaging service.  Preference could be used to load
  balance across multiple voice, video, and/or unified voice and video
  messaging servers by weight, for example.

  Finally, as with multiple records resulting from a typical ENUM query
  of the e164.arpa tree, it is up to the application using an ENUM
  resolver to determine which record(s) to use and which record(s) to
  ignore.  Implementers should take this into consideration and build
  logic into their applications that can select appropriately from
  multiple records based on business, network, or other rules.

8.2.  NAPTR Configuration Issues

  Implementers may wish to consider using regular expressions in order
  to reduce the size of individual NAPTRs.  This will have a
  significant effect on the overall size of the database involved.

9.  IANA Considerations

  This document registers the 'voicemsg' Enumservice type and the
  subtype "tel", "sip", "sips", "http", and "https" under the
  Enumservice registry described in the IANA considerations in RFC
  3761.  Details of this registration are provided in Section 4 of this
  document.

  This document registers the 'videomsg' Enumservice type and the
  subtype "sip", "sips", "http", and "https" under the Enumservice
  registry described in the IANA considerations in RFC 3761.  Details
  of this registration are provided in Section 5 of this document.

  This document registers the 'unifmsg' Enumservice type and the
  subtype "sip", "sips", "http", and "https" under the Enumservice
  registry described in the IANA considerations in RFC 3761.  Details
  of this registration are provided in Section 6 of this document.

10.  Acknowledgements

  The authors thank Rich Ferrise, Chris Harvey, Tong Zhou, and Hadriel
  Kaplan for their detailed assistance in developing the ideas behind
  this document in numerous brainstorming sessions, with information
  gleaned from their work to solve real application architecture
  issues.  The authors also thank Lawrence Conroy and Jean-Francois
  Mule for their feedback in developing this document.



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11.  Contributors

  Tong Zhou
  Comcast Cable Communications
  Email: [email protected]

  Richard Ferrise
  Comcast Cable Communications
  Email: [email protected]

  Chris Harvey
  Comcast Cable Communications
  Email: [email protected]

  Hadriel Kaplan
  Acme Packet
  Email: [email protected]

12.  References

12.1.  Normative References

  [1]   Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource
        Identifiers (URI) Dynamic Delegation Discovery System (DDDS)
        Application (ENUM)", RFC 3761, April 2004.

  [2]   ITU-T, "The International Public Telecommunication Numbering
        Plan", Recommendation E.164, May 1997.

  [3]   Mockapetris, P., "Domain names - concepts and facilities", STD
        13, RFC 1034, November 1987.

  [4]   Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        Three: The Domain Name System (DNS) Database", RFC 3403,
        October 2002.

  [5]   Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        One: The Comprehensive DDDS", RFC 3401, October 2002.

  [6]   Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        Two: The Algorithm", RFC 3402, October 2002.

  [7]   Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        Four: The Uniform Resource Identifiers (URI)", RFC 3404,
        October 2002.






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  [8]   Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        Five: URI.ARPA Assignment Procedures", BCP 65, RFC 3405,
        October 2002.

  [9]   Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966,
        December 2004.

  [10]  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.

  [11]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L.,
        Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol --
        HTTP/1.1", RFC 2616, June 1999.

  [12]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

12.2.  Informative References

  [13]  Peterson, J., Liu, H., Yu, J., and B. Campbell, "Using E.164
        numbers with the Session Initiation Protocol (SIP)", RFC 3824,
        June 2004.

  [14]  Vaudreuil, G., "Voice Message Routing Service", RFC 4238,
        October 2005.

  [15]  Brandner, R., Conroy, L., and R. Stastny, "IANA Registration
        for Enumservices email, fax, mms, ems, and sms", RFC 4355,
        January 2006.

  [16]  Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
        "Protocol Modifications for the DNS Security Extensions", RFC
        4035, March 2005.

  [17]  Atkins, D. and R. Austein, "Threat Analysis of the Domain Name
        System (DNS)", RFC 3833, August 2004.

  [18]  Foster, M., McGarry, T., and J. Yu, "Number Portability in the
        Global Switched Telephone Network (GSTN): An Overview", RFC
        3482, February 2003.

  [19]  Peterson, J., "enumservice registration for Session Initiation
        Protocol (SIP) Addresses-of-Record", RFC 3764, April 2004.








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Authors' Addresses

  Jason Livingood
  Comcast Cable Communications
  One Comcast Center
  1701 John F. Kennedy Boulevard
  Philadelphia, PA 19103
  USA
  EMail: [email protected]

  Donald Troshynski
  Acme Packet
  EMail: [email protected]






































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