draft-ietf-sipcore-content-id-07.txt   draft-ietf-sipcore-content-id-08.txt 
SIPCORE Working Group C. Holmberg SIPCORE Working Group C. Holmberg
Internet-Draft I. Sedlacek Internet-Draft I. Sedlacek
Updates: 5621 (if approved) Ericsson Updates: 5621, 5368, 6442 (if approved) Ericsson
Intended status: Standards Track June 28, 2017 Intended status: Standards Track August 31, 2017
Expires: December 30, 2017 Expires: March 4, 2018
Content-ID header field in Session Initiation Protocol (SIP) Content-ID header field in Session Initiation Protocol (SIP)
draft-ietf-sipcore-content-id-07 draft-ietf-sipcore-content-id-08
Abstract Abstract
This document specifies the Content-ID header field for usage in the This document specifies the Content-ID header field for usage in the
Session Initiation Protocol (SIP). The document also updates RFC Session Initiation Protocol (SIP). The document also updates RFC
5621, which only allows a Content-ID URL to reference a body-part 5621, which only allows a Content-ID URL to reference a body part
that is part of a multipart message-body. This update enables a that is part of a multipart message-body. This update enables a
Content-ID URL to reference a complete message-body and metadata Content-ID URL to reference a complete message-body and metadata
provided by some additional SIP header fields. provided by some additional SIP header fields.
This document updates RFC 5368 and RFC 6442, by clarifying their
usage of the SIP Content-ID header field.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 30, 2017. This Internet-Draft will expire on March 4, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 13 skipping to change at page 2, line 16
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Identifying a body part . . . . . . . . . . . . . . . . . 2 1.1. Identifying a body part . . . . . . . . . . . . . . . . . 2
1.2. Referencing a body part . . . . . . . . . . . . . . . . . 3 1.2. Referencing a body part . . . . . . . . . . . . . . . . . 3
1.3. Problem statement . . . . . . . . . . . . . . . . . . . . 3 1.3. Problem statement . . . . . . . . . . . . . . . . . . . . 3
1.4. Consequences . . . . . . . . . . . . . . . . . . . . . . 3 1.4. Consequences . . . . . . . . . . . . . . . . . . . . . . 4
1.4.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . 3 1.4.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . 4
1.4.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . 5 1.4.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . 5
1.5. Solution . . . . . . . . . . . . . . . . . . . . . . . . 6 1.5. Solution . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6. Backward compatibility . . . . . . . . . . . . . . . . . 7
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Content-ID header field . . . . . . . . . . . . . . . . . . . 7 3. Content-ID header field . . . . . . . . . . . . . . . . . . . 7
3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 7
3.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4. Procedures . . . . . . . . . . . . . . . . . . . . . . . 8 3.4. Procedures . . . . . . . . . . . . . . . . . . . . . . . 8
3.4.1. User Agent (UA) procedures . . . . . . . . . . . . . 8 3.4.1. User Agent (UA) procedures . . . . . . . . . . . . . 8
3.4.2. Proxy procedures . . . . . . . . . . . . . . . . . . 8 3.4.2. Proxy procedures . . . . . . . . . . . . . . . . . . 9
3.4.3. Example . . . . . . . . . . . . . . . . . . . . . . . 8 3.4.3. Example . . . . . . . . . . . . . . . . . . . . . . . 9
4. Update to RFC 5621 . . . . . . . . . . . . . . . . . . . . . 9 4. Update to RFC 5368 . . . . . . . . . . . . . . . . . . . . . 10
5. Security considerations . . . . . . . . . . . . . . . . . . . 10 5. Update to RFC 5621 . . . . . . . . . . . . . . . . . . . . . 10
6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 10 6. Update to RFC 6442 . . . . . . . . . . . . . . . . . . . . . 11
6.1. Header field . . . . . . . . . . . . . . . . . . . . . . 10 7. Security considerations . . . . . . . . . . . . . . . . . . . 12
7. Change log . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Normative references . . . . . . . . . . . . . . . . . . . . 11 8.1. Header field . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 9. Change log . . . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative references . . . . . . . . . . . . . . . . . . 14
10.2. Informative references . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
1.1. Identifying a body part 1.1. Identifying a body part
A SIP message consists of a start-line, one or more header fields, an A SIP message consists of a start-line, one or more header fields, an
empty line indicating the end of the header fields, and an optional empty line indicating the end of the header fields, and an optional
message-body, as specified in [RFC3261]. message-body, as specified in [RFC3261].
The message-body can be a non-multipart message-body or a multipart The message-body can be a non-multipart message-body or a multipart
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1.3. Problem statement 1.3. Problem statement
It is currently not specified how to uniquely identify a complete It is currently not specified how to uniquely identify a complete
message-body of a SIP message using a Content-ID header field, and message-body of a SIP message using a Content-ID header field, and
how to reference a complete message-body using a Content-ID URL. how to reference a complete message-body using a Content-ID URL.
NOTE: In [RFC5621], the Content-ID URL references a specific body NOTE: In [RFC5621], the Content-ID URL references a specific body
part only. part only.
Some existing specifications, for example [RFC5368], contain examples
that show usage of a SIP Content-ID header field referencing a
complete message-body, eventhough such usage has never been
specified.
1.4. Consequences 1.4. Consequences
The examples below shows the consequences of the problem described The examples below shows the consequences of the problem described
above. above.
1.4.1. Example 1 1.4.1. Example 1
If a User Agent Client (UAC) sends an INVITE request conveying If a User Agent Client (UAC) sends an INVITE request conveying
location as specified in [RFC6442], if the UAC decides not to include location as specified in [RFC6442], if the UAC decides not to include
an SDP offer, and if the location is conveyed by value, then the UAC an SDP offer, and if the location is conveyed by value, then the UAC
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o Specifies and registers the Content-ID header field as a SIP o Specifies and registers the Content-ID header field as a SIP
header field; and header field; and
o Specifies that, when used as a SIP header field, the Content-ID o Specifies that, when used as a SIP header field, the Content-ID
header field identifies the complete message-body, and metadata header field identifies the complete message-body, and metadata
provided by some additional SIP header fields, of the SIP message; provided by some additional SIP header fields, of the SIP message;
and and
o Updates [RFC5621], to enable a Content-ID URL to reference a o Updates [RFC5621], to enable a Content-ID URL to reference a
complete message-body and metadata provided by some additional SIP complete message-body and metadata provided by some additional SIP
header fields. header fields.
o Updates [RFC5368] and [RFC6442] by adding explicit text saying
that a SIP Content-ID header field can be used.
1.6. Backward compatibility
If an existing specification explicitly defines the usage of a
multipart message-body for carrying a single body part, that
specification MUST be updated in order to allow usage of a non-
multipart message-body for carrying the MIME entity, and for
referencing the whole message-body using a Content-ID URL.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Content-ID header field 3. Content-ID header field
3.1. Introduction 3.1. Introduction
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has no meaning outside of the message in which it is included. has no meaning outside of the message in which it is included.
3.3. Semantics 3.3. Semantics
The Content-ID header field included in the header fields of a SIP The Content-ID header field included in the header fields of a SIP
message identifies the message-body of the SIP message, and the message identifies the message-body of the SIP message, and the
metadata provided by: metadata provided by:
o a MIME-Version header field, if included in the header fields of o a MIME-Version header field, if included in the header fields of
the SIP message; and the SIP message; and
o any 'Content-' prefixed header fields (including the Content-ID o any 'Content-' prefixed header fields (including the Content-ID
header field itself) included in the header fields of the SIP header field itself) included in the header fields of the SIP
message. message.
The Content-ID header field can be included in any SIP message which The Content-ID header field can be included in any SIP message which
is allowed to contain a message-body. is allowed to contain a message-body.
NOTE: The message body identified by the Content-ID header field can NOTE: The message-body identified by the Content-ID header field can
be a non-multipart message-body or a multipart message-body. be a non-multipart message-body or a multipart message-body.
3.4. Procedures 3.4. Procedures
3.4.1. User Agent (UA) procedures 3.4.1. User Agent (UA) procedures
A UA MAY include a Content-ID header field in any SIP message that is A UA MAY include a Content-ID header field in any SIP message that is
allowed to contain a message-body. allowed to contain a message-body.
A UA MUST NOT include a Content-ID header field in any SIP message A UA MUST NOT include a Content-ID header field in any SIP message
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A proxy MUST NOT add a Content-ID header field in a SIP message. A proxy MUST NOT add a Content-ID header field in a SIP message.
A proxy MUST NOT modify a Content-ID header field included in a SIP A proxy MUST NOT modify a Content-ID header field included in a SIP
message. message.
A proxy MUST NOT delete a Content-ID header field from a SIP message. A proxy MUST NOT delete a Content-ID header field from a SIP message.
3.4.3. Example 3.4.3. Example
The figure shows an example from [RFC5368], where the SIP Content-ID The figure shows an example from [RFC5368], where the SIP Content-ID
header field is used to reference the message body (non-multipart) of header field is used to reference the message-body (non-multipart) of
a SIP message. a SIP message.
REFER sip:conf-123@example.com;gruu;opaque=hha9s8d-999a SIP/2.0 REFER sip:conf-123@example.com;gruu;opaque=hha9s8d-999a SIP/2.0
Via: SIP/2.0/TCP client.chicago.example.com Via: SIP/2.0/TCP client.chicago.example.com
;branch=z9hG4bKhjhs8ass83 ;branch=z9hG4bKhjhs8ass83
Max-Forwards: 70 Max-Forwards: 70
To: "Conference 123" <sip:conf-123@example.com> To: "Conference 123" <sip:conf-123@example.com>
From: Carol <sip:carol@chicago.example.com>;tag=32331 From: Carol <sip:carol@chicago.example.com>;tag=32331
Call-ID: d432fa84b4c76e66710 Call-ID: d432fa84b4c76e66710
CSeq: 2 REFER CSeq: 2 REFER
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<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<resource-lists xmlns="urn:ietf:params:xml:ns:resource-lists" <resource-lists xmlns="urn:ietf:params:xml:ns:resource-lists"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<list> <list>
<entry uri="sip:bill@example.com?method=BYE" /> <entry uri="sip:bill@example.com?method=BYE" />
<entry uri="sip:joe@example.org?method=BYE" /> <entry uri="sip:joe@example.org?method=BYE" />
<entry uri="sip:ted@example.net?method=BYE" /> <entry uri="sip:ted@example.net?method=BYE" />
</list> </list>
</resource-lists> </resource-lists>
4. Update to RFC 5621 4. Update to RFC 5368
This section updates the second paragraph in section 7 of [RFC5368],
by allowing usage of either a MIME Content-ID header field or a SIP
Content-ID header field to label the body part or the message-body
carrying the URI list.
OLD TEXT:
The Refer-To header field of a REFER request with multiple REFER-
Targets MUST contain a pointer (i.e., a Content-ID Uniform Resource
Locator (URL) as per RFC 2392 [RFC2392]) that points to the body part
that carries the URI list. The REFER-Issuer SHOULD NOT include any
particular URI more than once in the URI list.
NEW TEXT:
The Refer-To header field of a REFER request with multiple REFER-
Targets MUST contain a pointer (i.e., a Content-ID Uniform Resource
Locator (URL) as per RFC 2392 [RFC2392]) that points to the body part
or message-body that carries the URI list. The REFER-Issuer SHOULD
NOT include any particular URI more than once in the URI list. The
REFER request can use either a MIME Content-ID header field [RFC4483]
or a SIP Content-ID header field [RFCXXXX] to label the body part or
the message-body.
5. Update to RFC 5621
This section updates section 9.1 of [RFC5621], by allowing a Content- This section updates section 9.1 of [RFC5621], by allowing a Content-
ID URL to reference a message-body and the related metadata ID URL to reference a message-body and the related metadata
(Section 3.3), in addition to allowing a reference to a body part. (Section 3.3), in addition to allowing a reference to a body part.
OLD TEXT: OLD TEXT:
Content-ID URLs allow creating references to body parts. A given Content-ID URLs allow creating references to body parts. A given
Content-ID URL [RFC2392], which can appear in a header field or Content-ID URL [RFC2392], which can appear in a header field or
within a body part (e.g., in an SDP attribute), points to a within a body part (e.g., in an SDP attribute), points to a
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NEW TEXT: NEW TEXT:
Content-ID URLs allow the creation of references to body parts or Content-ID URLs allow the creation of references to body parts or
message-bodies (and the header fields describing the message-bodies (and the header fields describing the
message-bodies). A given Content-ID URL [RFC2392], which can appear message-bodies). A given Content-ID URL [RFC2392], which can appear
in a header field or within a body part (e.g., in an SDP attribute), in a header field or within a body part (e.g., in an SDP attribute),
points to a particular body part or the message-body (and the points to a particular body part or the message-body (and the
header fields describing the message-body). header fields describing the message-body).
5. Security considerations 6. Update to RFC 6442
This section updates the second paragraph in section 3.1 of
[RFC6442], by allowing usage of either a MIME Content-ID header field
or a SIP Content-ID header field to label the body part or the
message-body carrying the location data.
OLD TEXT:
In Figure 1, Alice is both the Target and the LS that is conveying
her location directly to Bob, who acts as an LR. This conveyance is
point-to-point: it does not pass through any SIP-layer intermediary.
A Location Object appears by-value in the initial SIP request as a
MIME body, and Bob responds to that SIP request as appropriate.
There is a 'Bad Location Information' response code introduced within
this document to specifically inform Alice if she conveys bad
location to Bob (e.g., Bob "cannot parse the location provided", or
"there is not enough location information to determine where Alice
is").
NEW TEXT:
In Figure 1, Alice is both the Target and the LS that is conveying
her location directly to Bob, who acts as an LR. This conveyance is
point-to-point: it does not pass through any SIP-layer intermediary.
A Location Object appears by-value in the initial SIP request as a
MIME body, and Bob responds to that SIP request as appropriate.
Either a MIME Content-ID header field [RFC4483] or the SIP Content-ID
header field [RFCXXXX] MUST be used to label the location
information. There is a 'Bad Location Information' response code
introduced within this document to specifically inform Alice if she
conveys bad location to Bob (e.g., Bob "cannot parse the location
provided", or "there is not enough location information to determine
where Alice is").
7. Security considerations
The Content-ID header field value MUST NOT reveal sensitive user The Content-ID header field value MUST NOT reveal sensitive user
information. information.
If the message-body associated with the Content-ID header field is an If the message-body associated with the Content-ID header field is an
encrypted body, it MUST NOT be possible to derive a key that can be encrypted body, it MUST NOT be possible to derive a key that can be
used to decrypt the body from the Content-ID header field value. used to decrypt the body from the Content-ID header field value.
6. IANA considerations 8. IANA considerations
This specification registers a new SIP header field according to the This specification registers a new SIP header field according to the
procedures in [RFC3261]. procedures in [RFC3261].
6.1. Header field 8.1. Header field
The header field described in Section 3 has been registered in the The header field described in Section 3 has been registered in the
"Header Fields" sub-registry of the "Session Initiation Protocol "Header Fields" sub-registry of the "Session Initiation Protocol
(SIP) Parameters" registry by adding a row with these values: (SIP) Parameters" registry by adding a row with these values:
[RFC EDITOR NOTE: Please replace XXXX with the RFC number of this [RFC EDITOR NOTE: Please replace XXXX with the RFC number of this
document when publishing] document when publishing]
Header Name: Content-ID Header Name: Content-ID
compact: compact:
Reference: RFCXXXX Reference: RFCXXXX
7. Change log 9. Change log
[RFC EDITOR NOTE: Please remove this section when publishing] [RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-ietf-sipcore-content-id-07
o Updates to affected RFCs.
o Editorial changes and clarifications based on IESG review.
Changes from draft-ietf-sipcore-content-id-06 Changes from draft-ietf-sipcore-content-id-06
o Editorial changes and clarifications based on Gen-ART review from o Editorial changes and clarifications based on Gen-ART review from
Elwyn Davies. Elwyn Davies.
Changes from draft-ietf-sipcore-content-id-05 Changes from draft-ietf-sipcore-content-id-05
o Changes based on AD comments from Ben Campell: o Changes based on AD comments from Ben Campell:
o - Clarifying that Content-ID header field value is unique within o - Clarifying that Content-ID header field value is unique within
the scope of a SIP message. the scope of a SIP message.
skipping to change at page 11, line 32 skipping to change at page 14, line 4
o Minor editorial fix. o Minor editorial fix.
Changes from draft-ietf-sipcore-content-id-03 Changes from draft-ietf-sipcore-content-id-03
o Changes based on doc shepard review: o Changes based on doc shepard review:
o - Reference to RFC 5234 added. o - Reference to RFC 5234 added.
o - SIP message example added. o - SIP message example added.
o - Editorial changes. o - Editorial changes.
Changes from draft-ietf-sipcore-content-id-02 Changes from draft-ietf-sipcore-content-id-02
o Editorial changes based on comments from Paul Kyzivat. o Editorial changes based on comments from Paul Kyzivat.
Changes from draft-ietf-sipcore-content-id-01 Changes from draft-ietf-sipcore-content-id-01
o Update to RFC 5621 added. o Update to RFC 5621 added.
o Editorial changes. o Editorial changes.
8. Normative references 10. References
10.1. Normative references
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996, Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<http://www.rfc-editor.org/info/rfc2045>. <https://www.rfc-editor.org/info/rfc2045>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc2119>. editor.org/info/rfc2119>.
[RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource [RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998, Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
<http://www.rfc-editor.org/info/rfc2392>. <https://www.rfc-editor.org/info/rfc2392>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008, DOI 10.17487/RFC5234, January 2008, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc5234>. editor.org/info/rfc5234>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008, DOI 10.17487/RFC5322, October 2008, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc5322>. editor.org/info/rfc5322>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc3261>. editor.org/info/rfc3261>.
[RFC5621] Camarillo, G., "Message Body Handling in the Session
Initiation Protocol (SIP)", RFC 5621,
DOI 10.17487/RFC5621, September 2009, <https://www.rfc-
editor.org/info/rfc5621>.
10.2. Informative references
[RFC5368] Camarillo, G., Niemi, A., Isomaki, M., Garcia-Martin, M., [RFC5368] Camarillo, G., Niemi, A., Isomaki, M., Garcia-Martin, M.,
and H. Khartabil, "Referring to Multiple Resources in the and H. Khartabil, "Referring to Multiple Resources in the
Session Initiation Protocol (SIP)", RFC 5368, Session Initiation Protocol (SIP)", RFC 5368,
DOI 10.17487/RFC5368, October 2008, DOI 10.17487/RFC5368, October 2008, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc5368>. editor.org/info/rfc5368>.
[RFC5621] Camarillo, G., "Message Body Handling in the Session
Initiation Protocol (SIP)", RFC 5621,
DOI 10.17487/RFC5621, September 2009,
<http://www.rfc-editor.org/info/rfc5621>.
[RFC6442] Polk, J., Rosen, B., and J. Peterson, "Location Conveyance [RFC6442] Polk, J., Rosen, B., and J. Peterson, "Location Conveyance
for the Session Initiation Protocol", RFC 6442, for the Session Initiation Protocol", RFC 6442,
DOI 10.17487/RFC6442, December 2011, DOI 10.17487/RFC6442, December 2011, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc6442>. editor.org/info/rfc6442>.
Authors' Addresses Authors' Addresses
Christer Holmberg Christer Holmberg
Ericsson Ericsson
Hirsalantie 11 Hirsalantie 11
Jorvas 02420 Jorvas 02420
Finland Finland
Email: christer.holmberg@ericsson.com Email: christer.holmberg@ericsson.com
 End of changes. 30 change blocks. 
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