Clarifications for When to Use the name-addr Production in SIP Messages
RFC 8217
| Document | Type | RFC - Proposed Standard (August 2017; No errata) | |
|---|---|---|---|
| Author | Robert Sparks | ||
| Last updated | 2018-12-20 | ||
| Replaces | draft-sparks-sipcore-name-addr-guidance | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Brian Rosen | ||
| Shepherd write-up | Show (last changed 2017-05-15) | ||
| IESG | IESG state | RFC 8217 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Ben Campbell | ||
| Send notices to | Brian Rosen <br@brianrosen.net> | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IANA Actions | ||
Internet Engineering Task Force (IETF) R. Sparks
Request for Comments: 8217 Oracle
Updates: 3261, 3325, 3515, 3892, 4508, August 2017
5002, 5318, 5360, 5502
Category: Standards Track
ISSN: 2070-1721
Clarifications for When to Use the name-addr Production in SIP Messages
Abstract
RFC 3261 constrained several SIP header fields whose grammar contains
the "name-addr / addr-spec" alternative to use name-addr when certain
characters appear. Unfortunately, it expressed the constraints with
prose copied into each header field definition, and at least one
header field was missed. Further, the constraint has not been copied
into documents defining extension headers whose grammar contains the
alternative.
This document updates RFC 3261 to state the constraint generically
and clarifies that the constraint applies to all SIP header fields
where there is a choice between using name-addr or addr-spec. It
also updates the RFCs that define extension SIP header fields using
the alternative to clarify that the constraint applies (RFCs 3325,
3515, 3892, 4508, 5002, 5318, 5360, and 5502).
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8217.
Sparks Standards Track [Page 1]
RFC 8217 name-addr Clarifications August 2017
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Updates to RFC 3261 . . . . . . . . . . . . . . . . . . . . . 4
4. Updates to RFCs Defining SIP Extension Header Fields . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[RFC3261] defines several header fields that contain URIs to allow
both a form that contains the bare URI (addr-spec) and one that
provides a name and the URI (name-addr). This subset, taken from the
ABNF [RFC5234] specified in [RFC3261], shows the relevant part of the
definition of the syntax of the "From" header field:
From = ( "From" / "f" ) HCOLON from-spec
from-spec = ( name-addr / addr-spec )
*( SEMI from-param )
name-addr = [ display-name ] LAQUOT addr-spec RAQUOT
addr-spec = SIP-URI / SIPS-URI / absoluteURI
The prose in Section 20.20 of [RFC3261], which discusses the "From"
header field, constrains how the production may be used by saying:
Even if the "display-name" is empty, the "name-addr" form
MUST be used if the "addr-spec" contains a comma, question
mark, or semicolon.
Sparks Standards Track [Page 2]
RFC 8217 name-addr Clarifications August 2017
Section 20.39 of [RFC3261], which discusses the "To" header field,
contains no such constraining text.
This constraint is specified slightly differently, but with the same
intent, in the introduction to Section 20 of [RFC3261]:
The Contact, From, and To header fields contain a URI. If the URI
contains a comma, question mark or semicolon, the URI MUST be
enclosed in angle brackets (< and >).
Unfortunately, this can be read to only apply to the Contact, From,
and To header fields, making it necessary to provide the constraint
explicitly in the prose discussing any other header field using the
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