One document matched: draft-ema-vpim-clid-00.txt

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.

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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



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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 


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   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


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    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


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   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 
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   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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