Internet Draft D. Dunne Document: draft-ema-vpim-clid-00.txt Nortel Networks Category: Standards Track Expires in Six Months July 14, 2000 Calling Line Identification for VPIM Messages STATUS OF THIS MEMO: This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 draft documents 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 "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. Abstract This document describes a method for identifying the originating party of a VPIM message. Table of Contents 1. Introduction 2. Calling Line Identification Field 2.1 Internal Call 2.2 External Call 3. Caller Name Field 4. Syntax 4.1 Calling Line Identification Syntax 4.2 Caller Name Syntax 4.3 Example 5. IANA Registration 6. Security Considerations 7. References 8. Author's Address 9. Full Copyright Statement Dunne Standards Track [Page 1]
Internet Draft Calling Line ID for VPIM Messages July 2000 1. Introduction There is currently a need for a mechanism to identify the originating party of a VPIM message, outside of the "FROM" header information. The telephone number and name of the caller are typically available from the telephone network, but where to store these in an Internet message is not obvious. This information is intended for use when the VPIM message format is used for storing "Call Answer" messages, i.e. the calling party leaves a voice message for the recipient, who was unable to answer the call. The VPIM specification [3] suggests the originating number be included as an Internet address, using the first method shown below. There are several other ways to store this information, but they all involve some manipulation of the "From" field. For example: 1. From: "416 555 1234" <non-mail-user@host> 2. From: "Unknown" <4165551234@host> 3. From: As a result, it is useful to be able to store the calling party's name and number as-is without manipulation. This would allow future generation of the proper Internet address, and also display of this information to the recipient. RFC2076 "Common Internet Message Headers" [4] currently lists "phone" as an Internet message header which would hold the originating party's telephone number, but it is listed as "non- standard", i.e. usage of this header is not in general recommended. It also has no defined format, making the information unparsable. There is no similar entry for the originator's name. It is proposed that two new message header fields be included to hold this information, namely the Calling Line Identification ("Caller-ID"), and Caller Name ("Caller-Name"). 2. Calling Line Identification Field The Calling Line Identification header ("Caller-ID") is to hold sufficient information for the recipient to call back, or reply to, the sender of the message. This leads to two distinct possibilities: internal and external calling. Note that for both possibilities, this field contains ONLY the digits of the number; it does not include any separating character (e.g. "-"). 2.1 Internal Call For an internal call (e.g. between two extensions within the same Dunne Standards Track [Page 2]
Internet Draft Calling Line ID for VPIM Messages July 2000 company), it is sufficient to relay only the extension of the calling party, based on the company dialling plan. 2.2 External Call For an international call, the CLID must be the full international number as described in E.164 [2], i.e. Country Code (CC), National Destination Code (NDC) and Subscriber Number (SN). No other information, such as prefixes or symbols (e.g. "+"), should be included. This requires provisioning for up to 15 digits. For a call within North America, it is sufficient to only include 10 digits as described in GR-31-CORE Issue 1 [1]. Though it is desirable that an international number NOT be truncated to 10 digits if it contains more, it is recognized that this will happen due to limitations of various systems. Also note that the GR-31-Core document also specifies how to include the date and time with the originating telephone number. This need not be followed, as there is an existing "Date" Internet header intended to hold this information. It is a local implementation decision whether this time or the local system time be recorded in the "Date" header. 3. Caller Name Field The name of the person sending the message is also important. It is to be included whether the call is internal or external. The name should be representable using the American Standard Code for Information Interchange (ASCII) character set. The length of the name field should also not exceed 15 characters, as defined in TR-NWT-001188 [6]. It may contain punctuation or white spaces as appropriate. 4. Syntax The syntax of both the Calling Line Identification and Caller Name according to ABNF [5] is as follows. 4.1 Calling Line Identification Syntax "Caller-ID" ":" 1*15DIGIT CRLF 4.2 Caller Name Syntax "Caller-Name" ":" 1*15CHAR CRLF 4.3 Example To: +19725551212@vm1.mycompany.com Caller-ID: 6137684087 Dunne Standards Track [Page 3]
Internet Draft Calling Line ID for VPIM Messages July 2000 Caller-Name: Derrick Dunne Date: Mon, 26 Aug 93 10:20:20 -0700 (CDT) MIME-Version: 1.0 (Voice 2.0) Content-type: Multipart/Voice-Message; Version=2.0; Boundary="MessageBoundary" Content-Transfer-Encoding: 7bit Message-ID: 123456789@VM2.mycompany.com Sensitivity: Private Importance: High 5. IANA Registration The values corresponding to the "Caller-ID" and "Caller-Name" fields are not fixed, and need not be registered. 6. Security Considerations There are two scenarios that must be considered. The first is mentioned in section 2.2 - the truncation of an international number to 10 digits. This could result in a misinterpretation of the resulting number. For instance, an international number (e.g. from Ireland) of the form "353 91 73 3307" could be truncated to "53 91 73 3307" if received in North America, and interpreted as "539 112 3456" - a seemingly "North American" style number. Thus leaving the recipient with the incorrect information to reply to the message. The second scenario is the possibility of sending an internal extension to an external recipient when a Call Answer message is forwarded. This poses two problems, the recipient is given the wrong phone number, and the company's dialling plan could be exposed. 7. References 1. Telcordia Technologies, "Class Feature: Calling Number Delivery Generic Requirements", GR-31-CORE Issue 1, June 2000 2. International Telecommunications Union - Standardization Sector, "Recommendation E.164, The International Public Telecommunication Numbering Plan", June 1997 3. Parsons, Vaudreuil, "Voice Profile for Internet Mail - version 2", draft-ietf-vpim-vpimv2r2-00.txt, July 2000 4. Palme, "Common Internet Message Headers", RFC2076, February 1997 5. Crocker and Overell (Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997 6. Telcordia Technologies, "CLASS Feature: Calling Name Delivery Generic Requirements", TR-NWT-001188, Issue 1, December 1991 Dunne Standards Track [Page 4]
Internet Draft Calling Line ID for VPIM Messages July 2000 7. Resnick (Editor), "Internet Message Format", draft-ietf-drums-msg- fmt-08.txt, January 2000 8. Author's Address Derrick Dunne Nortel Networks P.O. Box 3511, Station Ottawa, ON K1Y 4H7 Canada Phone: +1-613-768-4087 Fax: +1-613-763-4461 email: dunned@nortelnetworks.com 9. Full Copyright Statement 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. Dunne Standards Track [Page 5]
