Internet DRAFT - draft-aboba-avtcore-quic-multiplexing
draft-aboba-avtcore-quic-multiplexing
AVTCORE Working Group B. Aboba
INTERNET-DRAFT Microsoft Corporation
Category: Informational P. Thatcher
Expires: July 28, 2020 Google
C. Perkins
University of Glasgow
28 January 2020
QUIC Multiplexing
draft-aboba-avtcore-quic-multiplexing-04.txt
Abstract
If QUIC is to be used for peer-to-peer data transport with NAT
traversal, then it is necessary to be able to demultiplex QUIC and
other protocols used in WebRTC on a single UDP port. This memo
discusses a proposed scheme for demultiplexing.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 July 2020.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Informative references . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
QUIC [I-D.ietf-quic-transport] is a new network transport protocol.
While it is initially intended as a replacement for TCP in order to
better support HTTP/2 [RFC7540], with the introduction of datagram
support [I-D.pauly-quic-datagram] it will also support unreliable as
well as reliable transport. HTTP is an asymmetric client-server
protocol, but other uses of QUIC support peer-to-peer operation and
so will need effective NAT traversal using ICE [RFC5245], which which
makes use of STUN [RFC5389] and TURN [RFC5766] to discover NAT
bindings. Therefore for QUIC to be utilized for peer-to-peer data
transport, QUIC and STUN must be able to multiplex on the same port.
In a WebRTC scenario where RTP is used to transport audio and video
and QUIC is used for data exchange, SRTP [RFC3711] is keyed using
DTLS-SRTP [RFC5764] and therefore SRTP/SRTCP [RFC3550], STUN, TURN,
DTLS [RFC6347] and QUIC will need to be multiplexed on the same port.
Within the W3C, a Javascript API for the use of QUIC for peer-to-peer
data exchange [WEBRTC-QUIC] is under development within the ORTC
Community Group, and an Origin Trial [WEBRTC-QUIC-TRIAL] implementing
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an early version of this API shipped in the Chrome and Edge browsers.
Due to lack of demultiplexing support, the Origin Trial could only
support peer-to-peer use of QUIC over a standalone ICE transport, as
defined in [WEBRTC-ICE].
As noted in [RFC7983] Figure 3, protocol demultiplexing currently
relies upon differentiation based on the first octet, as follows:
+----------------+
| [0..3] -+--> forward to STUN
| |
| [16..19] -+--> forward to ZRTP
| |
packet --> | [20..63] -+--> forward to DTLS
| |
| [64..79] -+--> forward to TURN Channel
| |
| [128..191] -+--> forward to RTP/RTCP
+----------------+
Figure 1: RFC 7983 packet demultiplexing algorithm.
As noted by Colin Perkins and Lars Eggert in [QUIC-Issue][QUIC-MULTI]
this created a potential conflict with the design of the QUIC headers
described in versions of [I-D.ietf-quic-transport] prior to -08.
1.1. Terminology
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 [RFC2119].
2. Solution
As of draft 18, the QUIC Long Header packet type field defined in [I-
D.ietf-quic-transport] Section 17.2 appears as follows:
+-+-+-+-+-+-+-+-+
|1|1|T T|X|X|X|X|
+-+-+-+-+-+-+-+-+
Where:
T = Long Packet Type (0x0 - 0x3)
X = Type-Specific Bits.
This potentially produces values of the first octet in the ranges
192-255.
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The QUIC Short Header packet type field defined in [I-D.ietf-quic-
transport] Section 17.3 appears as follows:
+-+-+-+-+-+-+-+-+
|0|1|S|R|R|K|P P|
+-+-+-+-+-+-+-+-+
Where:
S = Spin Bit
R = Reserved bits
K = Key Phase bit
P = Packet Number Length.
This potentially produces values of the first octet in the ranges
64-127 (assuming that the reserved bits may not always be set to
zero).
As a result, the multiplexing scheme supported in -18 operates as
follows:
+----------------+
| [0..3] -+--> forward to STUN
| |
| [16..19] -+--> forward to ZRTP
| |
packet --> | [20..63] -+--> forward to DTLS
| |
| [64..79] -+--> forward to TURN Channel
| [64..127] -+--> forward to QUIC (Short Header)
| |
| [128..191] -+--> forward to RTP/RTCP
| [192..255] +--> forward to QUIC (Long Header)
+----------------+
Figure 3: Packet demultiplexing algorithm in Draft 18.
Note that while the above diagram has a potential conflict between
packets sent in TURN Channels and the QUIC short header, this
conflict is not considered serious for WebRTC where TURN Channels are
rarely used.
3. Security Considerations
The solution discussed in this document could potentially introduce
some additional security considerations beyond those detailed in
[RFC7983].
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Due to the additional logic required, if mis-implemented, heuristics
have the potential to mis-classify packets.
When QUIC is used for only for data exchange, the TLS-within-QUIC
exchange [I-D.ietf-quic-tls] derives keys used solely to protect the
QUIC data packets. If properly implemented, this should not affect
the transport of SRTP nor the derivation of SRTP keys via DTLS-SRTP,
but if badly implemented, both transport and key derivation could be
adversely impacted.
4. IANA Considerations
This document does not require actions by IANA.
5. References
5.1. Informative References
[I-D.ietf-quic-tls]
Thomson, M. and S. Turner, "Using Transport Layer Security
(TLS) to Secure QUIC", draft-ietf-quic-tls-25 (work in
progress), January 22, 2020.
[I-D.ietf-quic-transport]
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", draft-ietf-quic-transport-25 (work
in progress), January 22, 2020.
[I-D.pauly-quic-datagram]
Pauly, T., Kinnear, E. and D. Schinazi, "An Unreliable
Datagram Extension to QUIC", draft-pauly-quic-datagram-05
(work in progress), November 04, 2019.
[QUIC-Issue] Perkins, C., "QUIC header format/demultiplexing",
https://github.com/quicwg/base-drafts/issues/426, March,
2017.
[QUIC-MULTI] Perkins, C., "QUIC Multiplexing and Peer-to-Peer",
presentation to IETF AVTCORE WG at IETF 100,
<https://datatracker.ietf.org/meeting/100/materials/
slides-100-avtcore-quic-multiplexing-with-rtp-03>, November
2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI
10.17487/RFC2119, March 1997, <http://www.rfc-
editor.org/info/rfc2119>.
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[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July
2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, DOI 10.17487/RFC3711, March 2004,
<http://www.rfc-editor.org/info/rfc3711>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, DOI
10.17487/RFC5245, April 2010, <http://www.rfc-
editor.org/info/rfc5245>.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389, DOI
10.17487/RFC5389, October 2008, <http://www.rfc-
editor.org/info/rfc5389>.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure
Real-time Transport Protocol (SRTP)", RFC 5764, DOI
10.17487/RFC5764, May 2010, <http://www.rfc-
editor.org/info/rfc5764>.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, DOI
10.17487/RFC5766, April 2010, <http://www.rfc-
editor.org/info/rfc5766>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <http://www.rfc-editor.org/info/rfc6347>.
[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540, DOI
10.17487/RFC7540, May 2015, <https://www.rfc-
editor.org/info/rfc7540>.
[RFC7983] Petit-Huguenin, M. and G. Salgueiro, "Multiplexing Scheme
Updates for Secure Real-time Transport Protocol (SRTP)
Extension for Datagram Transport Layer Security (DTLS)",
RFC 7983, DOI 10.17487/RFC7983, September 2016,
<https://www.rfc-editor.org/info/rfc7983>.
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[WEBRTC-ICE] Thatcher, P. and B. Aboba, "ICE Transport Extensions for
WebRTC", W3C Editor's Draft (work in progress), January
2020, <https://w3c.github.io/webrtc-ice>
[WEBRTC-QUIC]
Thatcher, P. and B. Aboba, "QUIC API For Peer-to-Peer
Connections", W3C Community Group Draft (work in progress),
January 2020, <https://w3c.github.io/webrtc-quic>
[WEBRTC-QUIC-TRIAL]
Hampson, S., "RTCQuicTransport Coming to an Origin Trial
Near You (Chrome 73)", January 2019,
<https://developers.google.com/web/updates/
2019/01/rtcquictransport-api>
Acknowledgments
We would like to thank Martin Thomson, Roni Even and other
participants in the IETF QUIC and AVTCORE working groups for their
discussion of the QUIC multiplexing issue, and their input relating
to potential solutions.
Authors' Addresses
Bernard Aboba
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
USA
Email: bernard.aboba@gmail.com
Peter Thatcher
Google
747 6th St S
Kirkland, WA 98033
USA
Email: pthatcher@google.com
Colin Perkins
School of Computing Science
University of Glasgow
Glasgow G12 8QQ
United Kingdom
Email: csp@csperkins.org
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