Voice Messaging Directory Service
RFC 4237

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Network Working Group                                       G. Vaudreuil
Request for Comments: 4237                           Lucent Technologies
Category: Standards Track                                   October 2005

                   Voice Messaging Directory Service

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.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document provides details of the Voice Profile for Internet Mail
   (VPIM) directory service.  The service provides the email address of
   the recipient that is given a telephone number.  It optionally
   provides the spoken name of the recipient and the media capabilities
   of the recipient.

   The VPIM directory Schema provides essential additional attributes to
   recreate the voice mail user experience using standardized
   directories.  This user experience provides, at the time of
   addressing, basic assurances that the message will be delivered as
   intended.  This document combines two earlier documents, one from
   Anne Brown and one from Greg Vaudreuil, that define a voice messaging
   schema into a single working group submission.

Vaudreuil                   Standards Track                     [Page 1]
RFC 4237           Voice Messaging Directory Service        October 2005

Table of Contents

   1. Scope ...........................................................2
      1.1. Design Goals ...............................................2
      1.2. Performance Constraints ....................................2
      1.3. Scaling Constraints ........................................3
      1.4. Reliability Constraints ....................................3
   2. The VPIMUser Directory Schema ...................................3
      2.1. vPIMTelephoneNumber ........................................4
      2.2. vPIMRfc822Mailbox ..........................................4
      2.3. vPIMSpokenName .............................................4
      2.4. vPIMTextName ...............................................5
      2.5. vPIMSupportedAudioMediaTypes ...............................5
      2.6. vPIMSupportedMessageContext ................................5
      2.7. vPIMExtendedAbsenceStatus ..................................6
      2.8. vPIMSupportedUABehaviors ...................................6
      2.9. vPIMMaxMessageSize .........................................7
      2.10. vPIMSubMailboxes ..........................................8
   3. Security Considerations .........................................8
   4. IANA Considerations .............................................9
      4.1. Object Identifiers .........................................9
      4.2. Object Identifier Descriptors ..............................9
   5. References .....................................................10
      5.1. Normative References ......................................10
      5.2. Informative References ....................................10

1.  Scope

1.1.  Design Goals

   The VPIM directory Schema (VPIMDIR) is accessed from outside the
   enterprise or service provider domain using the recipient's telephone
   number.

1.2.  Performance Constraints

   Once the identity of the VPIM directory server is known, the email
   address, capabilities, and spoken name confirmation information can
   be retrieved.  This query is expected to use LDAP [LDAP], a
   connection-oriented protocol.  The protocol transaction includes
   multiple packet round-trips to execute the query and retrieval and is
   considered to be the highest latency element of the messaging
   service.  Further, retrieval of the confirmation information may
   require the return of a spoken name segment of up to 20kbytes (5
   seconds at 4kbytes/second).  Over a sufficiently engineered Internet
   connection, a 1250 ms response time is believed to be achievable over
   the Internet at large.

Vaudreuil                   Standards Track                     [Page 2]
RFC 4237           Voice Messaging Directory Service        October 2005

1.3.  Scaling Constraints

   A service provider's namespace is expected to include entries for
   tens of millions of subscribers in a flat namespace based on the VPIM
   inter-domain address form: telephone_number@domain_name.  A large
   corporation may have a hundred-thousand entries, while a large
   service provider may have tens of millions of entries in a single
   domain.  It is expected that there will be a single public address
   validation service for a given service provider's network.  It is
   believed that existing directory technology, including horizontal