Internet Draft Greg Vaudreuil Expires in six months Lucent Technologies December 1, 1999 Voice Messaging Directory Service: Address Validation Schema and Message Routing Schema 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 documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet Drafts as reference material or to cite them other than as a "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). 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 . 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. Vaudreuil, Parsons Expires 5/1/00 [Page 2] Internet Draft VPIM Directory December 1, 1999 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 Vaudreuil, Parsons Expires 5/1/00 [Page 3] Internet Draft VPIM Directory December 1, 1999 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. Vaudreuil, Parsons Expires 5/1/00 [Page 4] Internet Draft VPIM Directory December 1, 1999 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 ?? } Vaudreuil, Parsons Expires 5/1/00 [Page 5] Internet Draft VPIM Directory December 1, 1999 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. Vaudreuil, Parsons Expires 5/1/00 [Page 6] Internet Draft VPIM Directory December 1, 1999 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. Vaudreuil, Parsons Expires 5/1/00 [Page 7] Internet Draft VPIM Directory December 1, 1999 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 Vaudreuil, Parsons Expires 5/1/00 [Page 8] Internet Draft VPIM Directory December 1, 1999 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, , 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. Vaudreuil, Parsons Expires 5/1/00 [Page 9] Internet Draft VPIM Directory December 1, 1999 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 Vaudreuil, Parsons Expires 5/1/00 [Page 10]