draft-ietf-rtcweb-transports-00.txt   draft-ietf-rtcweb-transports-01.txt 
Network Working Group H. Alvestrand Network Working Group H. Alvestrand
Internet-Draft Google Internet-Draft Google
Intended status: Standards Track August 18, 2013 Intended status: Standards Track September 3, 2013
Expires: February 19, 2014 Expires: March 7, 2014
Transports for RTCWEB Transports for RTCWEB
draft-ietf-rtcweb-transports-00 draft-ietf-rtcweb-transports-01
Abstract Abstract
This document describes the data transport protocols used by RTCWEB, This document describes the data transport protocols used by RTCWEB,
including the protocols used for interaction with intermediate boxes including the protocols used for interaction with intermediate boxes
such as firewalls, relays and NAT boxes. such as firewalls, relays and NAT boxes.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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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 February 19, 2014. This Internet-Draft will expire on March 7, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Transport and Middlebox specification . . . . . . . . . . . . . 3 2. Transport and Middlebox specification . . . . . . . . . . . . . 3
2.1. System-provided interfaces . . . . . . . . . . . . . . . . 3 2.1. System-provided interfaces . . . . . . . . . . . . . . . . 3
2.2. Middle box related functions . . . . . . . . . . . . . . . 3 2.2. Middle box related functions . . . . . . . . . . . . . . . 4
2.3. Transport protocols implemented . . . . . . . . . . . . . . 4 2.3. Transport protocols implemented . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . . 6 6.2. Informative References . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . . 7
A.1. Changes from -00 to -01 . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
The IETF RTCWEB effort, part of the WebRTC effort carried out in The IETF RTCWEB effort, part of the WebRTC effort carried out in
cooperation between the IETF and the W3C, is aimed at specifying a cooperation between the IETF and the W3C, is aimed at specifying a
protocol suite that is useful for real time multimedia exchange protocol suite that is useful for real time multimedia exchange
between browsers. between browsers.
The overall effort is described in the RTCWEB overview document, The overall effort is described in the RTCWEB overview document,
[I-D.ietf-rtcweb-overview]. This document focuses on the data [I-D.ietf-rtcweb-overview]. This document focuses on the data
skipping to change at page 3, line 36 skipping to change at page 3, line 36
protocols are available to the implementations of the RTCWEB protocols are available to the implementations of the RTCWEB
protocols: protocols:
o UDP. This is the protocol assumed by most protocol elements o UDP. This is the protocol assumed by most protocol elements
described. described.
o TCP. This is used for HTTP/WebSockets, as well as for TURN/SSL o TCP. This is used for HTTP/WebSockets, as well as for TURN/SSL
and ICE-TCP. and ICE-TCP.
For both protocols, this specification assumes the ability to set the For both protocols, this specification assumes the ability to set the
DSCP code point of the sockets opened. It does not assume that the DSCP code point of the sockets opened on a per-packet basis, in order
DSCP codepoints will be honored, and does assume that they may be to achieve the prioritizations described in [I-D.ietf-rtcweb-qos].
zeroed or changed, since this is a local configuration issue. It does not assume that the DSCP codepoints will be honored, and does
assume that they may be zeroed or changed, since this is a local
configuration issue.
If DSCP code points can only be set on a per-socket basis, not per-
packet, one loses the ability to have the network discriminate
reliably between classes of traffic sent over the same transport, but
this does not prevent communication.
This specification does not assume that the implementation will have This specification does not assume that the implementation will have
access to ICMP or raw IP. access to ICMP or raw IP.
2.2. Middle box related functions 2.2. Middle box related functions
The primary mechanism to deal with middle boxes is ICE, which is an The primary mechanism to deal with middle boxes is ICE, which is an
appropriate way to deal with NAT boxes and firewalls that accept appropriate way to deal with NAT boxes and firewalls that accept
traffic from the inside, but only from the outside if it's in traffic from the inside, but only from the outside if it's in
response to inside traffic (simple stateful firewalls). response to inside traffic (simple stateful firewalls).
In order to deal with symmetric NATs, TURN MUST be supported. In order to deal with situations where both parties are behind NATs
which perform endpoint-dependent mapping (as defined in [RFC5128]
section 2.4), TURN [RFC5766] MUST be supported.
In order to deal with firewalls that block all UDP traffic, TURN over In order to deal with firewalls that block all UDP traffic, TURN
TCP MUST be supported. (QUESTION: What about ICE-TCP?) using TCP between the client and the server MUST be supported, and
TURN using TLS between the client and the server MUST be supported.
ICE TCP candidates [RFC6062] MAY be supported; this may allow
applications to achieve peer-to-peer communication across UDP-
blocking firewalls, but this also requires use of the SRTP/AVPF/TCP
profile of RTP.
The following specifications MUST be supported: The following specifications MUST be supported:
o ICE [RFC5245] o ICE [RFC5245]
o TURN, including TURN over TCP [[QUESTION: and TURN over TLS]], o TURN, including TURN over TCP[RFC5766].
[RFC5766].
TURN over TLS over TCP MAY be supported. (QUESTION: SHOULD? MUST?)
For referring to STUN and TURN servers, this specification depends on For referring to STUN and TURN servers, this specification depends on
the STUN URI, [I-D.nandakumar-rtcweb-stun-uri]. the STUN URI, [I-D.nandakumar-rtcweb-stun-uri].
Further discussion of the interaction of RTCWEB with firewalls is
contained in [I-D.hutton-rtcweb-nat-firewall-considerations]. This
document makes no requirements on interacting with HTTP proxies or
HTTP proxy configuration methods.
2.3. Transport protocols implemented 2.3. Transport protocols implemented
For data transport over the RTCWEB data channel For data transport over the RTCWEB data channel
[I-D.ietf-rtcweb-data-channel], RTCWEB implementations support SCTP [I-D.ietf-rtcweb-data-channel], RTCWEB implementations support SCTP
over DTLS over ICE. This is specified in over DTLS over ICE. This is specified in
[I-D.ietf-tsvwg-sctp-dtls-encaps]. Negotiation of this transport in [I-D.ietf-tsvwg-sctp-dtls-encaps]. Negotiation of this transport in
SCTP is defined in [I-D.ietf-mmusic-sctp-sdp]. SCTP is defined in [I-D.ietf-mmusic-sctp-sdp].
The setup protocol for RTCWEB data channels is described in The setup protocol for RTCWEB data channels is described in
[I-D.jesup-rtcweb-data-protocol]. [I-D.jesup-rtcweb-data-protocol].
For transport of media, secure RTP is used. The details of the For transport of media, secure RTP is used. The details of the
profile of RTP used are described in "RTP Usage" profile of RTP used are described in "RTP Usage"
[I-D.ietf-rtcweb-rtp-usage]. [I-D.ietf-rtcweb-rtp-usage].
RTCWEB implementations MUST support multiplexing of SCTP/DTLS and RTP RTCWEB implementations MUST support multiplexing of DTLS and RTP over
over the same port pair, as described in the DTLS_SRTP specification the same port pair, as described in the DTLS_SRTP specification
[RFC5764], section 5.1.2. [RFC5764], section 5.1.2. Further separation of the DTLS traffic
into SCTP and "other" is described in <need reference>.
3. IANA Considerations 3. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an Note to RFC Editor: this section may be removed on publication as an
RFC. RFC.
4. Security Considerations 4. Security Considerations
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Loreto, S. and G. Camarillo, "Stream Control Transmission Loreto, S. and G. Camarillo, "Stream Control Transmission
Protocol (SCTP)-Based Media Transport in the Session Protocol (SCTP)-Based Media Transport in the Session
Description Protocol (SDP)", draft-ietf-mmusic-sctp-sdp-04 Description Protocol (SDP)", draft-ietf-mmusic-sctp-sdp-04
(work in progress), June 2013. (work in progress), June 2013.
[I-D.ietf-rtcweb-data-channel] [I-D.ietf-rtcweb-data-channel]
Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Data Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Data
Channels", draft-ietf-rtcweb-data-channel-05 (work in Channels", draft-ietf-rtcweb-data-channel-05 (work in
progress), July 2013. progress), July 2013.
[I-D.ietf-rtcweb-qos]
Dhesikan, S., Druta, D., Jones, P., and J. Polk, "DSCP and
other packet markings for RTCWeb QoS",
draft-ietf-rtcweb-qos-00 (work in progress), October 2012.
[I-D.ietf-rtcweb-rtp-usage] [I-D.ietf-rtcweb-rtp-usage]
Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time
Communication (WebRTC): Media Transport and Use of RTP", Communication (WebRTC): Media Transport and Use of RTP",
draft-ietf-rtcweb-rtp-usage-07 (work in progress), draft-ietf-rtcweb-rtp-usage-07 (work in progress),
July 2013. July 2013.
[I-D.ietf-rtcweb-security] [I-D.ietf-rtcweb-security]
Rescorla, E., "Security Considerations for WebRTC", Rescorla, E., "Security Considerations for WebRTC",
draft-ietf-rtcweb-security-05 (work in progress), draft-ietf-rtcweb-security-05 (work in progress),
July 2013. July 2013.
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April 2010. April 2010.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer [RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure Security (DTLS) Extension to Establish Keys for the Secure
Real-time Transport Protocol (SRTP)", RFC 5764, May 2010. Real-time Transport Protocol (SRTP)", RFC 5764, May 2010.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using [RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, April 2010. Traversal Utilities for NAT (STUN)", RFC 5766, April 2010.
[RFC6062] Perreault, S. and J. Rosenberg, "Traversal Using Relays
around NAT (TURN) Extensions for TCP Allocations",
RFC 6062, November 2010.
6.2. Informative References 6.2. Informative References
[I-D.hutton-rtcweb-nat-firewall-considerations]
Stach, T., Hutton, A., and J. Uberti, "RTCWEB
Considerations for NATs, Firewalls and HTTP proxies",
draft-hutton-rtcweb-nat-firewall-considerations-01 (work
in progress), June 2013.
[I-D.ietf-rtcweb-overview] [I-D.ietf-rtcweb-overview]
Alvestrand, H., "Overview: Real Time Protocols for Brower- Alvestrand, H., "Overview: Real Time Protocols for Brower-
based Applications", draft-ietf-rtcweb-overview-06 (work based Applications", draft-ietf-rtcweb-overview-07 (work
in progress), February 2013. in progress), August 2013.
[I-D.jesup-rtcweb-data-protocol] [I-D.jesup-rtcweb-data-protocol]
Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel
Protocol", draft-jesup-rtcweb-data-protocol-04 (work in Protocol", draft-jesup-rtcweb-data-protocol-04 (work in
progress), February 2013. progress), February 2013.
[RFC5128] Srisuresh, P., Ford, B., and D. Kegel, "State of Peer-to-
Peer (P2P) Communication across Network Address
Translators (NATs)", RFC 5128, March 2008.
Appendix A. Change log
A.1. Changes from -00 to -01
o Clarified DSCP requirements, with reference to -qos-
o Clarified "symmetric NAT" -> "NATs which perform endpoint-
dependent mapping"
o Made support of TURN over TCP mandatory
o Made support of TURN over TLS a MAY, and added open question
o Added an informative reference to -firewalls-
o Called out that we don't make requirements on HTTP proxy
interaction (yet)
Author's Address Author's Address
Harald Alvestrand Harald Alvestrand
Google Google
Email: harald@alvestrand.no Email: harald@alvestrand.no
 End of changes. 17 change blocks. 
22 lines changed or deleted 83 lines changed or added

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