Internet Draft Greg Vaudreuil
Expires in six months Lucent Technologies
November 14, 2001
Voice Messaging Directory Service
<draft-ietf-vpim-vpimdir-01.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
This document is an Internet Draft. Internet Drafts are working
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Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
This Internet-Draft is in conformance with Section 10 of RFC2026.
Overview
This document provides details of the VPIM directory service. The
service provides the email address of the recipient given a telephone
number. It optionally provides the spoken name of the recipient and
the media capabilities of the recipient.
Please send comments on this document to the VPIM working group
mailing list <vpim@lists.neystadt.org>
Internet Draft VPIM Directory November 14, 2001
Working Group Summary
This document is a synthesis of two earlier Internet drafts that
define a voice messaging schema's into a single working group
submission. These documents are Anne Brown's <draft-ema-vpimdir-
schema-01.txt> and Greg Vaudreuil's <draft-vaudreuil-vpimdir-avs-
00.txt>.
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Table of Contents
1. ABSTRACT ..........................................................4
2. SCOPE .............................................................4
2.1 Design Goals ....................................................4
2.2 Performance Constraints .........................................4
2.3 Scaling Constraints .............................................4
2.4 Reliability Constraints .........................................4
3. THE VPIM DIRECTORY SCHEMA .........................................5
3.1 vPIMTelephoneNumber .............................................5
3.2 vPIMrfc822Mailbox ...............................................5
3.3 vPIMSpokenName ..................................................6
3.4 vPIMTextName ....................................................6
3.5 vPIMSupportedEncodingTypes ......................................6
3.6 vPIMextendedAbsenceStatus .......................................7
3.7 vPIMsupportedUABehaviors ........................................8
3.8 Maximum Message Size ............................................8
3.9 vPIMsubMailbox ..................................................9
4. SECURITY CONSIDERATIONS ...........................................9
5. REFERENCES ........................................................9
6. ACKNOWLEDGMENTS ..................................................10
7. COPYRIGHT NOTICE .................................................10
8. AUTHORS' ADDRESSES ...............................................11
9. CHANGES FROM -00 .................................................11
10. OPEN ISSUES ......................................................11
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1. Abstract
2. Scope
2.1 Design Goals
The VPIM directory Schema (VPIMDIR) is accessed from outside the
enterprise or service provider domain using the recipients telephone
number.
2.2 Performance Constraints
Once the identity of the VPIM directory server is known, the email
address, capabilities, and spoken name confirmation information can be
retreived. This query is expected to use LDAP, a connection-oriented
protocol. The protocol transaction includes multiple packet round-
trip to execute the query and retreival and is considered to be the
most at-risk element of the infrastructure. Further, retreival of the
confirmation information may require the return of a spoken name
segment 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.
2.3 Scaling Constraints
A service provider's namespace is expected to include entries for tens
of million 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 providers network. It is believed that
existing directory technology inclusing horizontal scaleability will
provide sufficient transaction throughput within the required latency
requirements to address this need. The only fundamental new
requirement this application imposes on directory servers beyond
similar existing services is the ability to return the recipients
spoken name, a record an order of magnitude larger than common textual
elements. Preliminary investigation suggests that storage and
retreival of spoken name will not add appreciable latency, however it
will add to the need for storage capacity.
2.4 Reliability Constraints
DNS provides well-documented redundancy and load-ballancing
capabilities for the VPIMDIR. However, the latency requirements to
the end-user may not permit client-side fail-over to a secondary
server and may require the directory server to be implemented as a
high-availablity service.
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3. The VPIM Directory Schema
VPIMUser OBJECT-CLASS ::= {
AUXILLARY
SUBCLASS OF INETPerson
MUST CONTAIN
(vPIMrfc822Mailbox,
vPIMtelephoneNumber )
MAY CONTAIN
(vPIMSpokenName $
vPIMsupportedUABehaviors $
vPIMSupportedEncodingTypes $
vPIMTextName $
vPIMextendedAbsenceStatus $
vPIMMaxMessageSize $
vPIMsubMailboxes)
ID }
The vPIMUser is a auxillary object.
When present, the vPIMUser may contain information useful to validate
that the dialed telephone number corresponds to the intended
recipient. This object may further provide capabilities information
and mailbox status information useful to guide composition by the
sending user and to set delivery expectations at sending time.
3.1 vPIMTelephoneNumber
The normal search is for the full E164 form of the telephone number,
including any sub-addressing portion.
telephoneNumber ATTRIBUTE ::= {
WITH SYNTAX caseIgnoreIA5StringSyntax
(SIZE (1 .. 20)) -- from RFC 1274
ID ?? }
Example: A north american telephone number with the subaddress of 12
would be represented as +12145551212+12 .
3.2 vPIMrfc822Mailbox
The attribute vPIMrfc822Mailbox stores the inter-domain SMTP address
of the voice mailbox associated with a given telephone number. It is
defined as a distinct attribute to distinguish it from the
rfc822Mailbox attribute that may be used for other purposes. Although
it would be preferable to define vPIMrfc822Mailbox as a subtype of
rfc822Mailbox, it is defined here as an entirely new attribute because
some directory implementations do not support sub-typing.
ASN.1 definition:
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vPIMrfc822Mailbox ATTRIBUTE ::= {
WITH SYNTAX caseIgnoreIA5StringSyntax
(SIZE (1 .. 64)) -- from RFC 1274
ID ?? }
BNF definition:
(2.16.840.1.113694.1.2.1.1.2 NAME 'vPIMrfc822Mailbox'
EQUALITY 1.3.6.1.4.1.1466.109.114.2
SYNTAX '1.3.6.1.4.1.1466.115.121.1.26 {256}')
3.3 vPIMSpokenName
The vPIMSpokenName attribute is an octet string and should be encoded
in 32 kbit/s ADPCM exactly as defined by [32KADPCM]. vPIMSpokenName
shall contain the spoken name of the user in the voice of the user.
The length of the spoken name segment must not exceed 5 seconds.
Private or additional encoding types are outside the scope of this
version.
The ASN.1 definition for X.500 implementations is:
vPIMSpokenName ATTRIBUTE ::= {
WITH SYNTAX OCTET STRING
(SIZE (1..ub-vpim-at-vPIMSpokenName)
EQUALITY MATCHING RULE octetStringMatch
ID id-vpim-at-vPIMSpokenName }
ub-vpim-at-vPIMSpokenName INTEGER ::= 4000
The BNF definition for use with LDAP is:
(2.16.840.1.113694.1.2.1.1.3 NAME 'vPIMSpokenName'
EQUAILTY 2.5.13.17
SYNTAX '1.3.6.1.4.1.1466.115.121.1.40 {4000}')
3.4 vPIMTextName
The text name is designed to be consistent with the text name
databases used for calling name delivery service of caller ID and when
cached may be used for address-by-name functions within a telephone
user interface.
vPIMTextName ATTRIBUTE ::= {
WITH SYNTAX IA5String
(SIZE (1..20))
ID ?? }
OPEN ISSUE The character set of this attribute is not yet determined.
3.5 vPIMSupportedEncodingTypes
The vPIMSupportedEncodingTypes attribute indicates the type(s) of
encodings that can be received at the address specified in
vPIMrfc822Mailbox.
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The ASN.1 definition for X.500 implementations is:
vPIMSupportedEncodingTypes ATTRIBUTE ::= {
WITH SYNTAX DirectoryString
EQUALITY MATCHING RULE caseIgnoreMatch
ID id-vpim-at-vPIMSupportedEncodingTypes }
The BNF definition of vPIMSupportedEncodingTypes for use with
LDAP is:
(2.16.840.1.113694.1.2.1.1.4 NAME
'vPIMSupportedEncodingTypes'
EQUALITY 2.5.13.2
SYNTAX '1.3.6.1.4.1.1466.115.121.1.15')
The allowable values of DirectoryString for this version of the schema
are:
audio/32KADPCM
image/tiff
Additional publicly defined extensions, registered with IANA as
specified in RFC 2048, may be used. Non-standard and private encoding
types must be indicated by prepending the new type name with either
"X-" or "x-".
The existance of the value "image/tiff" indicates that simple-mode fax
is enabled for the mailbox whose address is defined by the
vPIMrfc822mailbox attribute.
3.6 vPIMextendedAbsenceStatus
It is common to have an attribute to indicate to the subscriber
whether the recipient is likely to check messages in the near future.
This feature called "extended absence" provides an advisory message at
sending time. It is similar in concept to "vacation notices" common
for textual email but has it's own cultural and operational nuances.
extendedAbsenceStatus ATTRIBUTE ::= {
WITH SYNTAX IA5string
(SIZE (1..10))
ID ?? }
The three values defined are:
"Off", "On", "MsgBlocked"
"Off" indicates that the recipient either does not support extended
absence or has not set such an indicator. "Off" if the default
condition if this attribute is not returned.
"On" indicates that the recipient has set an extended absence
indicator, but the mailbox is still accepting messages for review at
an unspecified future time.
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"MsgBlocked" indicates that the recipient has set an extended absence
indicator and the mailbox is temporarly configured to reject incoming
messages. Messages should not be sent to the recipient if this value
is returned in the extendedAbsenceStatus attribute.
3.7 vPIMsupportedUABehaviors
Internet mail does not provide facilities for the sender to know
whether the recipient supports a number of optional features that can
be requested or indicated in the RFC822 headers. This attribute
provides a list of the attributes considered optional by VPIM and
other vendor-specific attributes that may be supported by the
recipient. If this attribute is not supported, only those attributes
listed as manditory in VPIM are assumed to be supported. Undisclosed
behaviors may be indicated in the RFC822 message, however there is no
assurance by the receiving system of their support.
VPIMSupportedUABehaviors ATTRIBUTE ::= {
WITH SYNTAX IA5String
(SIZE (1..30))
MULTIVALUE
ID ?? }
The following behaviors:
MessageDispositionNotication
The presense of the MessageDispositionNotification value indicates
that the recipient will send a MDN in response to an MDN request.
These may be further extended without standardization to include
proprietary user interface functional extensions. These proprietary
extension values must be prefixed with an X.
3.8 Maximum Message Size
At the time of composition, the message can be checked for acceptable
length using the maximum message size attribute. Maximum message size
is an attribute usually configured by policy of the receiving system,
typically in units of minutes. While ESMTP provides a mechanism at
the transport layer to determine if a message is too long, that is an
unreliable guide to the composer when multiple encodings, multiple
media, or variable bit-rate encodings are supported.
The ASN.1 definition for X.500 implementations is:
vPIMMaxMessageSize ATTRIBUTE ::= {
WITH SYNTAX NumericString
EQUALITY MATCHING RULE numericStringMatch
ID id-vpim-at-vPIMMaxMessageSize}
The BNF definition for use with LDAP is:
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(2.16.840.1.113694.1.2.1.1.5 NAME 'vPIMMaxMessageSize'
EQUALITY 2.5.13.8
SYNTAX '1.3.6.1.4.1.1466.115.121.1.36')
3.9 vPIMsubMailbox
This attribute indicates the presence of sub-mailboxes for the queried
telephone number. This information may be used to provide a post-dial
sub-addressing menu to the sender.
subMailbox ATTRIBUTE ::= {
WITH SYNTAX IA5String
(SIZE (1..9999))
MULTIVALUE
ID ?? }
The allowable values include a list of submailbox numbers with a
numeric range of 1-9999. The user interface may use this information
to prompt the sender to select a sub-mailbox. Spoken names associated
with each sub-mailbox may be individually retrieved by subsequent
queries to the recipient's VPIMDIR service.
4. Security Considerations
The following are known security issues taken into consideration in
the definition of this directory service.
1) Service provider customer information is very sensitive, especially
in this time of local phone competition. Service providers require
the maximum flexibility to protect this data. Because of the dense
nature of telephone number assignments, this data is subject to "go
fish" queries via repeated LDAP queries to determine a complete list
of current or active messaging subscribers. To reduce the value of
this retreived data, service providers may limit disclosure of data
useful for telemarketing such as the textual name and disclose only
information useful to the sender such as the recipients spoken name, a
data element much harder to auto-process.
2) Service providers operate in a regulated environment where certian
information about a subscriber must not be disclosed. Voice Messaging
is subject to caller-ID blocking restrictions, restrictions enforced
in the telephony network. No such protection is available on the
Internet. The protection of this data is essential, but is up to the
individual service providers to appropriately limit dislosure of this
information.
5. References
[32KADPCM] G. Vaudreuil and G. Parsons, "Toll Quality Voice - 32 kbit/s
ADPCM: MIME Sub-type Registration", RFC 2422, September 1998.
[MIMEDIR] F. Dawson, T. Howes, & M. Smith, "A MIME Content-Type for
Directory Information", Work In Progress, <draft-ietf-asid-mime-
direct-06.txt>, March 1998
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[E164] CCITT Recommendation E.164 (1991), Telephone Network and ISDN
Operation, Numbering, Routing and Mobile Service - Numbering Plan
for the ISDN Era.
[VPIM2] Vaudreuil, Greg, Parsons, Glen, "Voice Profile for Internet
Mail, Version 2", RFC 2421, September 1998.
6. Acknowledgments
This experimental directory builds upon the earlier work of Carl
Malamud and Marshall Rose in thier TPC.INT remote printing experiment
and the work lead by Anne Brown as part of the EMA voice messaging
committee's directory effort. Anne Brown has provided important
leadership and was a co-author of the original draft of this document.
Bernhard Elliot working with the TMIA has provided most of the
organizational impetus to get this project moving, a substantial task
given the sometimes slow and bureaucratic nature of the voice mail
industry and regulatory environment.
Dave Dudley and the Messaging Aliance (TMA) for their early work in
pioneering a shared directory service for voice messaging and their
continuing efforts to apply those learnings to this effort.
7. Copyright Notice
"Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN
WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE."
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8. Authors' Addresses
Gregory M. Vaudreuil
Lucent Technologies,
7291 Williamson Rd
Dallas, TX 75214
United States
Phone/Fax: +1-972-733-2722
Email: GregV@ieee.org
9. Changes from -00
Changes the schema from a structural object to an auxillary object
under INETPerson. This makes the schema more compatible with other
related directory applications while potentially reducing performance
by changing accesses based on telephone number from directory reads to
directory searches.
Changes the schema attributes to all be prefixed by vPIM. This is to
reduce the chance of schema collision.
10. Open Issues
Should the submailbox include non-numeric submailboxes as are common
in Internet mail?
The formal ASN and BNF in this draft is badly broken. The schema
notation requires fixing by someone expert in this domain. Volunteers
are urgently sought by the author.
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