draft-ietf-straw-b2bua-rtcp-13.txt   draft-ietf-straw-b2bua-rtcp-14.txt 
STRAW Working Group L. Miniero STRAW Working Group L. Miniero
Internet-Draft Meetecho Internet-Draft Meetecho
Intended status: Standards Track S. Garcia Murillo Intended status: Standards Track S. Garcia Murillo
Expires: March 30, 2017 Medooze Expires: April 24, 2017 Medooze
V. Pascual V. Pascual
Oracle Oracle
September 26, 2016 October 21, 2016
Guidelines to support RTCP end-to-end in Back-to-Back User Agents Guidelines to support RTCP end-to-end in Back-to-Back User Agents
(B2BUAs) (B2BUAs)
draft-ietf-straw-b2bua-rtcp-13 draft-ietf-straw-b2bua-rtcp-14
Abstract Abstract
SIP Back-to-Back User Agents (B2BUAs) are often envisaged to also be SIP Back-to-Back User Agents (B2BUAs) are often designed to also be
on the media path, rather than just intercepting signalling. This on the media path, rather than just intercepting signalling. This
means that B2BUAs often implement an RTP/RTCP stack as well, thus means that B2BUAs often implement an RTP/RTCP stack as well, thus
leading to separate multimedia sessions that the B2BUA correlates and leading to separate multimedia sessions that the B2BUA correlates and
bridges together. If not disciplined, though, this behaviour can bridges together. If not disciplined, though, this behaviour can
severely impact the communication experience, especially when severely impact the communication experience, especially when
statistics and feedback information contained in RTCP messages get statistics and feedback information contained in RTCP messages get
lost because of mismatches in the reported data. lost because of mismatches in the reported data.
This document defines the proper behaviour B2BUAs should follow when This document defines the proper behaviour B2BUAs should follow when
also acting on the signalling/media plane in order to preserve the also acting on the signalling/media plane in order to preserve the
skipping to change at page 1, line 45 skipping to change at page 1, line 45
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 March 30, 2017. This Internet-Draft will expire on April 24, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 30 skipping to change at page 2, line 30
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Signalling/Media Plane B2BUAs . . . . . . . . . . . . . . . . 4 3. Signalling/Media Plane B2BUAs . . . . . . . . . . . . . . . . 4
3.1. Media Relay . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Media Relay . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Media-aware Relay . . . . . . . . . . . . . . . . . . . . 6 3.2. Media-aware Relay . . . . . . . . . . . . . . . . . . . . 6
3.3. Media Terminator . . . . . . . . . . . . . . . . . . . . 10 3.3. Media Terminator . . . . . . . . . . . . . . . . . . . . 10
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. Change Summary . . . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 7. Change Summary . . . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . 15 9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
Session Initiation Protocol [RFC3261] Back-to-Back User Agents Session Initiation Protocol [RFC3261] Back-to-Back User Agents
(B2BUAs) are SIP entities that can act as a logical combination of (B2BUAs) are SIP entities that can act as a logical combination of
both a User Agent Server (UAS) and a User Agent Client (UAC). As both a User Agent Server (UAS) and a User Agent Client (UAC). As
such, their behaviour is not always completely adherent to the such, their behaviour is not always completely adherent to the
standards, and can lead to unexpected situations. [RFC7092] presents standards, and can lead to unexpected situations. [RFC7092] presents
a taxonomy of the most commonly deployed B2BUA implementations, a taxonomy of the most commonly deployed B2BUA implementations,
skipping to change at page 11, line 28 skipping to change at page 11, line 28
independently on each side, as the B2BUA would terminate RTCP. In independently on each side, as the B2BUA would terminate RTCP. In
that case, the B2BUA SHOULD advertize and negotiate support for that case, the B2BUA SHOULD advertize and negotiate support for
Reduced-Size if available, and MUST NOT otherwise. Reduced-Size if available, and MUST NOT otherwise.
4. IANA Considerations 4. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
5. Security Considerations 5. Security Considerations
This document, does not introduce any additional consideration to
those described by the aforementioned standard documents. There are
some aspects related to security that should be highlighted, though.
The discussion made in the previous sections on the management of The discussion made in the previous sections on the management of
RTCP messages by a B2BUA worked under the assumption that the B2BUA RTCP messages by a B2BUA worked under the assumption that the B2BUA
has actually access to the RTP/RTCP information itself. This is has actually access to the RTP/RTCP information itself. This is
indeed true if we assume that plain RTP and RTCP is being handled, indeed true if we assume that plain RTP and RTCP is being handled,
but may not be once any security is enforced on RTP packets and RTCP but may not be once any security is enforced on RTP packets and RTCP
messages by means of SRTP [RFC3711]. messages by means of SRTP [RFC3711].
While typically not an issue in the Media Relay case, where RTP and While typically not an issue in the Media Relay case, where RTP and
RTCP packets are forwarded without any modification no matter whether RTCP packets are forwarded without any modification no matter whether
security is involved or not, this could definitely have an impact on security is involved or not, this could definitely have an impact on
skipping to change at page 12, line 23 skipping to change at page 12, line 19
willingly or not, to situations not unlike an attack. To make a willingly or not, to situations not unlike an attack. To make a
simple example, an improper management of a REMB feedback message simple example, an improper management of a REMB feedback message
containing, e.g., information on the limited bandwidth availability containing, e.g., information on the limited bandwidth availability
for a user, may lead to missing or misleading information to its for a user, may lead to missing or misleading information to its
peer. This may cause the peer to increase the encoder bitrate, maybe peer. This may cause the peer to increase the encoder bitrate, maybe
up to a point where a user with poor connectivity will inevitably be up to a point where a user with poor connectivity will inevitably be
choked by an amount of data it cannot process. This scenario may choked by an amount of data it cannot process. This scenario may
thus result in what looks like a Denial of Service (DOS) attack thus result in what looks like a Denial of Service (DOS) attack
towards the user. towards the user.
6. Change Summary 6. IANA Considerations
This document has no IANA actions.
7. Change Summary
Note to RFC Editor: Please remove this whole section. Note to RFC Editor: Please remove this whole section.
The following are the major changes between the 13 and the 14
versions of the draft:
o Removed first paragraph of Security Considerations which was
unclear.
o Added an IANA Considerations section to clarify there are no
actions.
The following are the major changes between the 12 and the 13 The following are the major changes between the 12 and the 13
versions of the draft: versions of the draft:
o Updated authors' affiliations and mail addresses. o Updated authors' affiliations and mail addresses.
The following are the major changes between the 11 and the 12 The following are the major changes between the 11 and the 12
versions of the draft: versions of the draft:
o Addressed remaining points in Ben's second review. o Addressed remaining points in Ben's second review.
skipping to change at page 14, line 35 skipping to change at page 14, line 43
o Added a reference to RTP topologies, and tried a mapping as per- o Added a reference to RTP topologies, and tried a mapping as per-
discussion in London. discussion in London.
o Added more RTCP message types to the Media-Aware section. o Added more RTCP message types to the Media-Aware section.
o Clarified that fixing the 'rtcp' SDP attribute is important. o Clarified that fixing the 'rtcp' SDP attribute is important.
o Added a new section on the impact of media security. o Added a new section on the impact of media security.
7. Acknowledgements 8. Acknowledgements
The authors would like to thank Flavio Battimo and Pierluigi Palma The authors would like to thank Flavio Battimo and Pierluigi Palma
for their invaluable feedback in the early stages of the document. for their invaluable feedback in the early stages of the document.
The authors would also like to thank Colin Perkins, Bernard Aboba, The authors would also like to thank Colin Perkins, Bernard Aboba,
Albrecht Schwarz, Hadriel Kaplan, Keith Drage, Jonathan Lennox, Albrecht Schwarz, Hadriel Kaplan, Keith Drage, Jonathan Lennox,
Stephen Farrell, Magnus Westerlund and Simon Perreault for their Stephen Farrell, Magnus Westerlund and Simon Perreault for their
constructive comments, suggestions, and reviews that were critical to constructive comments, suggestions, and reviews that were critical to
the formulation and refinement of this document. the formulation and refinement of this document.
8. References 9. References
8.1. Normative References 9.1. Normative References
[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,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[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,
skipping to change at page 15, line 31 skipping to change at page 15, line 40
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
July 2003, <http://www.rfc-editor.org/info/rfc3550>. July 2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC7656] Lennox, J., Gross, K., Nandakumar, S., Salgueiro, G., and [RFC7656] Lennox, J., Gross, K., Nandakumar, S., Salgueiro, G., and
B. Burman, Ed., "A Taxonomy of Semantics and Mechanisms B. Burman, Ed., "A Taxonomy of Semantics and Mechanisms
for Real-Time Transport Protocol (RTP) Sources", RFC 7656, for Real-Time Transport Protocol (RTP) Sources", RFC 7656,
DOI 10.17487/RFC7656, November 2015, DOI 10.17487/RFC7656, November 2015,
<http://www.rfc-editor.org/info/rfc7656>. <http://www.rfc-editor.org/info/rfc7656>.
8.2. Informative References 9.2. Informative References
[RFC7092] Kaplan, H. and V. Pascual, "A Taxonomy of Session [RFC7092] Kaplan, H. and V. Pascual, "A Taxonomy of Session
Initiation Protocol (SIP) Back-to-Back User Agents", Initiation Protocol (SIP) Back-to-Back User Agents",
RFC 7092, DOI 10.17487/RFC7092, December 2013, RFC 7092, DOI 10.17487/RFC7092, December 2013,
<http://www.rfc-editor.org/info/rfc7092>. <http://www.rfc-editor.org/info/rfc7092>.
[RFC7667] Westerlund, M. and S. Wenger, "RTP Topologies", RFC 7667, [RFC7667] Westerlund, M. and S. Wenger, "RTP Topologies", RFC 7667,
DOI 10.17487/RFC7667, November 2015, DOI 10.17487/RFC7667, November 2015,
<http://www.rfc-editor.org/info/rfc7667>. <http://www.rfc-editor.org/info/rfc7667>.
 End of changes. 13 change blocks. 
19 lines changed or deleted 29 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/