Network Working Group C. Allocchio
Request for Comments: 3191 GARR-Italy
Obsoletes: 2303 October 2001
Updates: 2846
Category: Standards Track
Minimal GSTN address format in Internet Mail
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This memo describes a simple method of encoding Global Switched
Telephone Network (GSTN) addresses (commonly called "telephone
numbers") in the local-part of Internet email addresses, along with
an extension mechanism to allow encoding of additional standard
attributes needed for email gateways to GSTN-based services.
1. Introduction
As with all Internet mail addresses, the left-hand-side (local-part)
of an address generated according to this specification, is not to be
interpreted except by an MTA that handles messages for the domain
given in the right-hand-side.
Since the very first e-mail to GSTN services gateway appeared, a
number of different methods to specify a GSTN address as an e-mail
address have been used by implementors. Several objectives for this
methods have been identified, like to enable an e-mail user to access
GSTN services from his/her e-mail interface, to allow some kind of
"GSTN over e-mail service" transport (possibly reducing the costs of
GSTN long distance transmissions) while using the existing e-mail
infrastructure.
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RFC 3191 Minimal GSTN address format in Internet Mail October 2001
This memo describes the MINIMAL addressing method to encode GSTN
addresses into e-mail addresses and the standard extension mechanism
to allow definition of further standard elements. The opposite
problem, i.e., to allow a traditional numeric-only GSTN device user
to access the e-mail transport service, is not discussed here.
The IANA registration templates which MUST be used to register any
standard element defined according to this specification are given in
the "IANA Considerations" chapter (section 7 of this document).
All implementations supporting this GSTN over e-mail service MUST
support as a minimum the specification described in this document.
The generic complex case of converting the entirety of GTSN
addressing into e-mail is out of scope in this minimal specification.
1.1 Terminology and Syntax conventions
In this document the formal definitions are described using ABNF
syntax, as defined into [7]. This memo also uses some of the "CORE
DEFINITIONS" defined in "APPENDIX A - CORE" of that document. The
exact meaning of the capitalized words
"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", "OPTIONAL"
is defined in reference [6].
In this document the following new terms are also defined:
I-pstn device:
a device which has an Internet domain name and it is able to
communicate either directly or indirectly with the GSTN
network;
mta-I-pstn:
the Internet domain name which identifies uniquely an I-pstn
device over the Internet;
pstn-email:
the complete Internet e-mail address structure which is used to
transport a GSTN address over the Internet e-mail service.
2. Minimal GSTN address
The minimal specification of a GSTN address within an e-mail address
is as follows:
Allocchio Standards Track [Page 2]
RFC 3191 Minimal GSTN address format in Internet Mail October 2001
pstn-address = pstn-mbox [ qualif-type1 ]
pstn-mbox = service-selector "=" global-phone
service-selector = 1*( DIGIT / ALPHA / "-" )
; note that SP (space) is not allowed in
; service-selector.
; service-selector MUST be handled as a case
; INSENSITIVE string by implementations.
Other specifications adopting the "pstn-address" definition MUST
datatracker.ietf.org