Network Working Group H. Alvestrand
Internet-Draft Google
Intended status: Standards Track August 18, 2013
Expires: February 19, 2014
Transports for RTCWEB
draft-ietf-rtcweb-transports-00
Abstract
This document describes the data transport protocols used by RTCWEB,
including the protocols used for interaction with intermediate boxes
such as firewalls, relays and NAT boxes.
Requirements Language
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 RFC 2119 [RFC2119].
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 19, 2014.
Copyright Notice
Copyright (c) 2013 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
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Transport and Middlebox specification . . . . . . . . . . . . . 3
2.1. System-provided interfaces . . . . . . . . . . . . . . . . 3
2.2. Middle box related functions . . . . . . . . . . . . . . . 3
2.3. Transport protocols implemented . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
The IETF RTCWEB effort, part of the WebRTC effort carried out in
cooperation between the IETF and the W3C, is aimed at specifying a
protocol suite that is useful for real time multimedia exchange
between browsers.
The overall effort is described in the RTCWEB overview document,
[I-D.ietf-rtcweb-overview]. This document focuses on the data
transport protocos that are used by conforming implementations.
This protocol suite is designed for WebRTC, and intends to satisfy
the security considerations described in the WebRTC security
documents, [I-D.ietf-rtcweb-security] and
[I-D.ietf-rtcweb-security-arch].
2. Transport and Middlebox specification
2.1. System-provided interfaces
The protocol specifications used here assume that the following
protocols are available to the implementations of the RTCWEB
protocols:
o UDP. This is the protocol assumed by most protocol elements
described.
o TCP. This is used for HTTP/WebSockets, as well as for TURN/SSL
and ICE-TCP.
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 codepoints will be honored, and does assume that they may be
zeroed or changed, since this is a local configuration issue.
This specification does not assume that the implementation will have
access to ICMP or raw IP.
2.2. Middle box related functions
The primary mechanism to deal with middle boxes is ICE, which is an
appropriate way to deal with NAT boxes and firewalls that accept
traffic from the inside, but only from the outside if it's in
response to inside traffic (simple stateful firewalls).
In order to deal with symmetric NATs, TURN MUST be supported.
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In order to deal with firewalls that block all UDP traffic, TURN over
TCP MUST be supported. (QUESTION: What about ICE-TCP?)
The following specifications MUST be supported:
o ICE [RFC5245]
o TURN, including TURN over TCP [[QUESTION: and TURN over TLS]],
[RFC5766].
For referring to STUN and TURN servers, this specification depends on
the STUN URI, [I-D.nandakumar-rtcweb-stun-uri].
2.3. Transport protocols implemented
For data transport over the RTCWEB data channel
[I-D.ietf-rtcweb-data-channel], RTCWEB implementations support SCTP
over DTLS over ICE. This is specified in
[I-D.ietf-tsvwg-sctp-dtls-encaps]. Negotiation of this transport in
SCTP is defined in [I-D.ietf-mmusic-sctp-sdp].
The setup protocol for RTCWEB data channels is described in
[I-D.jesup-rtcweb-data-protocol].
For transport of media, secure RTP is used. The details of the
profile of RTP used are described in "RTP Usage"
[I-D.ietf-rtcweb-rtp-usage].
RTCWEB implementations MUST support multiplexing of SCTP/DTLS and RTP
over the same port pair, as described in the DTLS_SRTP specification
[RFC5764], section 5.1.2.
3. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
4. Security Considerations
Security considerations are enumerated in [I-D.ietf-rtcweb-security].
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5. Acknowledgements
This document is based on earlier versions embedded in
[I-D.ietf-rtcweb-overview], which were the results of contributions
from many RTCWEB WG members.
6. References
6.1. Normative References
[I-D.ietf-mmusic-sctp-sdp]
Loreto, S. and G. Camarillo, "Stream Control Transmission
Protocol (SCTP)-Based Media Transport in the Session
Description Protocol (SDP)", draft-ietf-mmusic-sctp-sdp-04
(work in progress), June 2013.
[I-D.ietf-rtcweb-data-channel]
Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Data
Channels", draft-ietf-rtcweb-data-channel-05 (work in
progress), July 2013.
[I-D.ietf-rtcweb-rtp-usage]
Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time
Communication (WebRTC): Media Transport and Use of RTP",
draft-ietf-rtcweb-rtp-usage-07 (work in progress),
July 2013.
[I-D.ietf-rtcweb-security]
Rescorla, E., "Security Considerations for WebRTC",
draft-ietf-rtcweb-security-05 (work in progress),
July 2013.
[I-D.ietf-rtcweb-security-arch]
Rescorla, E., "WebRTC Security Architecture",
draft-ietf-rtcweb-security-arch-07 (work in progress),
July 2013.
[I-D.ietf-tsvwg-sctp-dtls-encaps]
Jesup, R., Loreto, S., Stewart, R., and M. Tuexen, "DTLS
Encapsulation of SCTP Packets",
draft-ietf-tsvwg-sctp-dtls-encaps-01 (work in progress),
July 2013.
[I-D.nandakumar-rtcweb-stun-uri]
Nandakumar, S., Salgueiro, G., Jones, P., and M. Petit-
Huguenin, "URI Scheme for Session Traversal Utilities for
NAT (STUN) Protocol", draft-nandakumar-rtcweb-stun-uri-05
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(work in progress), July 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
April 2010.
[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, May 2010.
[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, April 2010.
6.2. Informative References
[I-D.ietf-rtcweb-overview]
Alvestrand, H., "Overview: Real Time Protocols for Brower-
based Applications", draft-ietf-rtcweb-overview-06 (work
in progress), February 2013.
[I-D.jesup-rtcweb-data-protocol]
Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel
Protocol", draft-jesup-rtcweb-data-protocol-04 (work in
progress), February 2013.
Author's Address
Harald Alvestrand
Google
Email: harald@alvestrand.no
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