One document matched: draft-vaudreuil-vpimdir-avs-00.txt
Internet Draft Greg Vaudreuil
Expires in six months Lucent Technologies
December 1, 1999
Voice Messaging Directory Service:
Address Validation Schema
and
Message Routing Schema
<draft-vaudreuil-vpimdir-avs-00.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 (1999). All Rights Reserved.
This Internet-Draft is in conformance with Section 10 of RFC2026.
Overview
This document provides details of the address validation service of an
experimental voice messaging directory service. The directory service
is described in [vpime164]. This address validation portion of the
service provides both address confirmation and capabilities discovery
for a voice message recipient using a common LDAP schema.
Please send comments on this document to the author, Greg Vaudreuil
<gregv@lucent.com>.
Internet Draft VPIM Directory December 1, 1999
Working Group Summary
This document is not the product of an IETF working group. It
documents an inter-company voice message interchange experiment
conducted over the Internet as a project of the Telemessaging Industry
Association (TMIA) http://www.tmia.org. The TMIA is a consortium of
large North American wireline and wireless telephone companies.
This service is similar in many respects to the RESCAP work. It is
expected that RESCAP will supercede the particulars of this
experiemental schema when complete.
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Table of Contents
1. ABSTRACT ..........................................................4
2. SCOPE .............................................................4
2.1 Design Goals ....................................................4
3. ADDRESS VALIDATION SERVER DISCOVERY ...............................4
4. ADDRESS VALIDATION SERVICE (AVS) ..................................5
4.1 vPIMrfc822Mailbox ...............................................5
4.2 vPIMSpokenName ..................................................6
4.3 vPIMTextName ....................................................6
4.4 vPIMSupportedEncodingTypes ......................................6
4.5 extendedAbsenceStatus ...........................................6
4.6 supportedUABehaviors ............................................7
4.7 Maximum Message Size ............................................8
4.8 subMailbox ......................................................8
4.9 mailRecipient ...................................................8
5. SECURITY CONSIDERATIONS ...........................................8
6. REFERENCES ........................................................9
7. ACKNOWLEDGMENTS ...................................................9
8. COPYRIGHT NOTICE .................................................10
9. AUTHORS' ADDRESSES ...............................................10
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1. Abstract
2. Scope
2.1 Design Goals
Rapid searching of the flat namespace within a service provider domain
keyed by the email address using the Address Resolution Service
[vpimars]. A service provider's namespace is expected to include
several million-subscriber entries based on the VPIM inter-domain
address form: telephone number@domain_name.
The Address Validation Schema (AVS) is accessed from outside the
enterprise or service provider domain using the inter-domain forms of
the VPIM email address.
The Email Routing schema is designed to find the intra-domain forms of
the VPIM address for routing to the appropriate voice mail machine
within the domain.
3. Address Validation Server Discovery
The address validation server is found by querying DNS for the SRV
record associated with the domain name of the recipient as found in
the address resolution step.
SRV records for the AVS
Example:
Query: voice.sp.net
Response: SRV=avs1.serviceprovider.net weight=10
SRV=avs2.serviceprovider.net weight=20
Given the lack of elegant client-side redundancy for LDAP, and the real-
time requirements for a response, the AVS service should be provided on
a high-availability server to ensure the service is available on the
first try.
To facilitate higher system availability, it is recommended that AVS
servers be deployed in redundant sets. These servers should be listed in
the SRV records with various weightings. The querying system should
attempt a connection to the lowest weight AVS server. If it is down,
the second should be contacted.
Because the AVS server location and query step is part of a real-time
name confirmation, various implementation approaches may be used. One
such approach for the querying platform is to maintain state for a set
of frequently queried servers such that if a lower weighted server is
recently failed, the querying platform can use that state information to
immediately send a query to a higher weighted AVS server.
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Another possible approach is to send tandem queries to two or more AVS
servers. The first response is used to satisfy the address validation
need and subsequent responses are discarded.
4. Address Validation Service (AVS)
VPIMUser OBJECT-CLASS ::= {
STRUCTURAL
SUBCLASS OF top
MUST CONTAIN
(vPIMrfc822Mailbox)
MAY CONTAIN
(vPIMSpokenName $
vPIMsupportedUABehaviors $
vPIMSupportedEncodingTypes $
vPIMTextName $
extendedAbsenceStatus $
vPIMMaxMessageSize $
subMailboxes $
mailRecipient )
ID }
The vPIMUser is a structural object indexed by the vPIMRFC822Mailbox.
The existence of this object signifies that the recipient valid for
the purposes of sending voice messages.
When present, the vPIMUser may contain information useful to validate
that the VPIM address 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.
When available, the mailRecipient attribute provides routing
information necessary to deliver the voice message to the appropriate
voice messaging system within a service provider's domain. This
potentially confidential information is not expected to be made
available outside the domain but to be used by the inbound mail router
of the service provider. This capability is expected to be obsoleted
by the work resulting in the IETF LASER working group.
4.1 vPIMrfc822Mailbox
The normal search is for the interdomain form of vPIMAddress, an
attribute constructed with the E.164 form of the telephone number
concatenated with the domain name of the destination network. The
domain name of the destination network is found using facilities
described in [VPIMARS].
vPIMrfc822Mailbox ATTRIBUTE ::= {
WITH SYNTAX caseIgnoreIA5StringSyntax
(SIZE (1 .. 64)) -- from RFC 1274
ID ?? }
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4.2 vPIMSpokenName
The spoken name of the recipient may contain up to 20kbytes of G.726
ADPCM encoded spoken audio [g726]. (32kbits/sec * 5seconds)
vPIMSpokenName ATTRIBUTE ::= {
WITH SYNTAX OCTET STRING
(SIZE (1..20,000))
ID ?? }
4.3 vPIMTextName
The text name is designed to be consistent with the text name
databases used for calling name delivery service of caller ID.
vPIMTextName ATTRIBUTE ::= {
WITH SYNTAX IA5String
(SIZE (1..20))
ID ?? }
The character set of this attribute is not yet determined, but is
currently set to US-ASCII. This is expected to be modified to conform
to the requirements for multi-lingual text handling.
4.4 vPIMSupportedEncodingTypes
This object provides a list of MIME types the recipient will accept.
vPIMSupportedEncodingTypes ATTRIBUTE ::= {
WITH SYNTAX Ia5String
(SIZE (1..20))
MULTIVALUE
ID ?? }
The MIME types supported by VPIM are:
Audio/32kADPCM
Image/TIFF-F; application-faxbw
These may be further extended without standardization to include IANA
registered, proprietary encodings and additional media types provided
they are uniquely identified by their MIME type.
4.5 extendedAbsenceStatus
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.
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extendedAbsenceStatus ATTRIBUTE ::= {
WITH SYNTAX IA5string
(SIZE (1..10))
ID ?? }
The three values defined are:
"Off", "On", "MsgBlocked"
"Off" if the default condition if this attribute is not returned.
"Off" indicates that the recipient either does not support extended
absence or has not set such an indicator.
"On" indicates that the recipient has set an extended absence
indicator, but the mailbox is still accepting messages for review at a
future time.
"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.
4.6 supportedUABehaviors
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.
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4.7 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.
vPIMMaxMessageSize ATTRIBUTE ::= {
WITH SYNTAX NumericString
ID ????}
The vPIMMaxMessageSize is reported in integer number of seconds of
audio content. No indication of maximum fax message size is implied.
4.8 subMailbox
At the time of addressing, the address validation query may indicate
the presence of sub-mailboxes for the entered address. 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.
4.9 mailRecipient
The mailRecipient is the attribute that provides the identity of the
recipient on a local voice messaging systems.b
vPIMMailbox ATTRIBUTE ::= {
WITH SYNTAX caseIgnoreIA5StringSyntax
(SIZE (1 .. 64)) -- from RFC 1274
ID ?? }
5. 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
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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.
6. References
[ADPCM] 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
[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.
[VPIMe164] Vaudreuil, Greg, "Voice Messaging Directory Service:
Principles of Operation", work-in-progress.
[VPIMARS] Vaudreuil, Greg, "Voice Messaging Directory Service:
DNS-based", work-in-progress.
[SRV] Gulbrandsen, A., Vixie, P., "A DNS RR for specifying the location
of services (DNS SRV)", RFC 2052, October 1996.
7. 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.
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.
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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.
8. Copyright Notice
"Copyright (C) The Internet Society (1999). 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."
9. Authors' Addresses
Gregory M. Vaudreuil
Lucent Technologies,
Communications Application Group
17080 Dallas Parkway
Dallas, TX 75248-1905
United States
Phone/Fax: +1-972-733-2722
Email: GregV@Lucent.Com
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