One document matched: draft-ema-vpim-clid-01.txt
Differences from draft-ema-vpim-clid-00.txt
VPIM Working Group Jason Collins
Internet Draft Nortel Networks
Document: <draft-ema-vpim-clid-01.txt> November 2000
Category: Standards Track
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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Table of Contents
1. Abstract ........................................................2
2. Conventions used in this document ...............................2
3. Introduction ....................................................2
4. Calling Line Identification Field ...............................3
4.1 Internal Call ...............................................3
4.2 External Call ...............................................3
5. Caller Name Field ...............................................4
6. Formal Syntax ...................................................4
6.1 Calling Line Identification Syntax ..........................4
6.2 Caller Name Syntax ..........................................4
6.3 Example .....................................................4
7. Security Considerations .........................................4
8. References ......................................................5
9. Acknowledgments .................................................5
10. Author's Addresses .............................................5
11. Full Copyright Statement .......................................6
1. Abstract
This document describes a method for identifying the originating
calling party for a stored VPIM message.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC-2119.
3. 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 there is no
obvious header field to store this in an Internet message.
This information is intended for use when the VPIM message format is
used for storing "Call Answer" voice messages in an Internet Mail
message store, i.e. the calling party leaves a voice message for the
recipient, who was unable to answer the call.
[VPIMV2R2] 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: "John Doe" <4165551234@host>
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3. From: unknown:;
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] 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").
4. 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 MUST contain only the
digits of the number and MUST be representable using the American
Standard Code for Information Interchange (ASCII) character set; it
does not include any separating character (e.g. "-").
4.1 Internal Call
For an internal call (e.g. between two extensions within the same
company), it is sufficient to relay only the extension of the
calling party, based on the company dialing plan.
4.2 External Call
For an international call, the CLID must be the full international
number as described in [E.164], i.e. Country Code (CC), National
Destination Code (NDC) and Subscriber Number (SN). Other
information, such as prefixes or symbols (e.g. "+"), MUST NOT 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]. 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 [GR-31-Core] also specifies how to include the date
and time with the originating telephone number. This MAY be
followed, as there is an existing "Date" Internet header intended to
hold this information. It is a local implementation decision
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whether this time or the local system time be recorded in the "Date"
header.
5. Caller Name Field
The name of the person sending the message is also important. If
available, it is to be included whether the call is internal or
external. The name MUST be representable using the International
Reference Alphabet (IRA), formerly know as International Alphabet
No.5 or IA5. This is the character set used to transmit the caller
name in the PSTN.
The IRA character set contains a number of options that help specify
national and application oriented versions. If there is no agreement
between parties to use these options, then the default character set
"International Reference Version (IRV)" will be chosen. The
graphical characters of IRV and ASCII are coded exactly the same.
As a result, for the caller name header defined in this document,
characters are represented with ASCII characters.
The length of the name field MUST NOT exceed 15 characters, as
defined in [GR-1188-CORE]. It MAY contain punctuation or white
spaces as appropriate.
6. Formal Syntax
Both Calling Line Identification and Caller Line follow the syntax
specification using the augmented Backus-Naur Form (BNF) as
described in [RFC2234].
6.1 Calling Line Identification Syntax
"Caller-ID" ":" 1*15DIGIT CRLF
6.2 Caller Name Syntax
"Caller-Name" ":" 1*15CHAR CRLF
6.3 Example
To: +19725551212@vm1.mycompany.com
Caller-ID: 6137684087
7. Security Considerations
There are a few 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.
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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 dialing plan could be exposed.
The final concern deals with exercising character options that are
available in coding the Calling Name field. An international system
may send a message with coding options that are not available on the
receiving system. Thus giving the recipient an incorrect Caller
Name.
8. References
[VPIMV2R2] Vaudreuil, Greg, Parsons, Glenn, "Voice Profile for
Internet Mail, version 2", <draft-ietf-vpim-vpimv2r2-01.txt>,
November 2000.
[RFC2076] Palme, "Common Internet Message Headers", RFC 2076,
February 1997
[ASCII] American National Standards Institute (ANSI), Coded
Character Set - 7-Bit American National Standard Code for
Information Interchange, ANSI X3.4, 1986.
[RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and
Demon Internet Ltd., November 1997
[E.164] ITU-T Recommendation E.164 (1997), "The international public
telecommunication numbering plan"
[GR-1188-CORE] Telecordia Technologies, "CLASS Feature: Calling Name
Delivery Generic Requirements", GR-1188-CORE, Issue 1, June 2000
[GR-31-CORE] Telecordia Technologies, "CLASS Feature: Calling Number
Delivery", GR-31-CORE, Issue 1, June 2000
[T.50] ITU-T Recommendation T.50 (1992), "International Reference
Alphabet (IRA)"
9. Acknowledgments
The previous author of this document was Derrick Dunne. The author
would like to thank Derrick for his contributions.
10. Author's Addresses
Jason Collins
Nortel Networks
Ottawa, ON K1Y 4H7
Phone: +1-613-768-4087
Email: jcolli1@nortelnetworks.com
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11. Full Copyright Statement
Copyright (C) The Internet Society (2000). 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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