AVTCORE/MMUSIC Working Groups S. Dawkins Internet-Draft Tencent America LLC Intended status: Standards Track 8 September 2021 Expires: 12 March 2022 SDP Offer/Answer for RTP using QUIC as Transport draft-dawkins-sdp-rtp-quic-00 Abstract This document describes these new SDP "proto" attribute values: "QUIC", "QUIC/RTP/SAVP", "QUIC/RTP/AVPF", and "QUIC/RTP/SAVPF", and describes how SDP Offer/Answer can be used to set up an RTP connection using QUIC as a transport protocol. These proto values are necessary to allow the use of QUIC as an underlying transport protocol for applications that commonly use SDP as a session signaling protocol to set up RTP connections with UDP as its underlying transport protocol, such as SIP and WebRTC. 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 https://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 12 March 2022. Copyright Notice Copyright (c) 2021 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 (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components Dawkins Expires 12 March 2022 [Page 1] Internet-Draft SDP O/A for RTP over QUIC September 2021 extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Notes for Readers . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Contribution and Discussion Venues for this draft. . . . 3 1.4. Scope of this document . . . . . . . . . . . . . . . . . 3 1.5. Assumptions for this document . . . . . . . . . . . . . . 3 2. Open Questions (probably not for this draft, but could have implications on SDP Offer/Answer) . . . . . . . . . . . . 4 3. Identifiers and Attributes . . . . . . . . . . . . . . . . . 4 3.1. Protocol Identifiers . . . . . . . . . . . . . . . . . . 4 3.1.1. The QUIC proto . . . . . . . . . . . . . . . . . . . 4 3.1.2. The QUIC/RTP/SAVP proto . . . . . . . . . . . . . . . 5 3.1.3. The QUIC/RTP/AVPF proto . . . . . . . . . . . . . . . 5 3.1.4. The QUIC/RTP/SAVPF proto . . . . . . . . . . . . . . 6 3.2. A QUIC/RTP/AVPF Offer . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 4.1. Proto Registrations . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction This document describes these new SDP "proto" attribute values: "QUIC", "QUIC/RTP/SAVP", "QUIC/RTP/AVPF", and "QUIC/RTP/SAVPF", and describes how SDP Offer/Answer ([RFC3264]) can be used to set up an RTP ([RFC3550]) connection using QUIC ([RFC9000]) as a transport protocol. These proto values are necessary to allow the use of QUIC as an underlying transport protocol for applications that commonly use SDP as a session signaling protocol to set up RTP connections with UDP as its underlying transport protocol, such as SIP ([RFC3261]) and WebRTC ([RFC8825]). Dawkins Expires 12 March 2022 [Page 2] Internet-Draft SDP O/A for RTP over QUIC September 2021 1.1. Notes for Readers This document is intended for publiication as a standards-track RFC in the IETF stream, but has not been adopted by any IETF working group, and does not carry any special status within the IETF. 1.2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 ([RFC2119]) ([RFC8174]) when, and only when, they appear in all capitals, as shown here. 1.3. Contribution and Discussion Venues for this draft. (Note to RFC Editor - if this document ever reaches you, please remove this section) This document is under development in the Github repository at https://github.com/SpencerDawkins/sdp-rtp-quic. Readers are invited to open issues and send pull requests with contributed text for this document, or to send them to the author via email. 1.4. Scope of this document This document focuses on the IANA registration and description of the RTP sessions using SDP Offer/Answer, as would be the case for many current RTP applications in common use, such as SIP ([RFC3261]) and WebRTC ([RFC8825]). This document is intended as complementary to [I-D.engelbart-rtp-over-quic], which largely focuses on RTP/RTCP encapsulation in QUIC datagrams, so that the SDP experts can focus on SDP offer/answer aspects, and the RTP experts can focus on RTP/RTCP encapsulation aspects. 1.5. Assumptions for this document This document assumes that for RTP-over-QUIC, it is useful to register these AVP profiles using QUIC, in order to allow existing SIP and RTCWEB RTP applications to migrate more easily to QUIC: * RTP/SAVP ("The Secure Real-time Transport Protocol (SRTP)"), as defined in [RFC3711]. Dawkins Expires 12 March 2022 [Page 3] Internet-Draft SDP O/A for RTP over QUIC September 2021 * RTP/AVPF ("Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)"), as defined in [RFC4585]. * RTP/SAVPF ("Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)"), as defined in [RFC5124]. This document assumes that any implementation adding support for RTP- over-QUIC could reasonably add support for BUNDLE ([RFC8843]), "rtcp- mux" ([RFC5761]). 2. Open Questions (probably not for this draft, but could have implications on SDP Offer/Answer) * RTP (and RTCP) headers and payloads will be entirely encrypted using QUIC ([RFC9000]), as secured by TLS 1.3 handshake ([RFC9001]), between QUIC endpoints. It's worth thinking more about how that maps onto expected deployment scenarios like centralized multiparty conferencing, and also whether WebRTC really requires SAVPF with double encryption (i.e. SRTP encryption, and then QUIC encryption). No opinions here yet, just noting the question for now. * When QUIC establishes connections, it uses IP addresses but then expects applications to use connection IDs to refer to connections, even if the underlying IP addresses change because of NAT binding, and even if the QUIC implementation performs QUIC connection migration itself, so the underlying IP addresses change. RTP applications expect to use IP addresses, not QUIC connection IDs. Must we specify an RTP/RTCP adaptation layer, similar to [I-D.ietf-quic-http] for HTTP/3? 3. Identifiers and Attributes As much as possible, these are reused from other specifications, with references to the original definitions. 3.1. Protocol Identifiers 3.1.1. The QUIC proto The 'QUIC' protocol identifier is similar to the 'UDP' and 'TCP' protocol identifiers in that it only describes the transport protocol, and not the upper-layer protocol. Dawkins Expires 12 March 2022 [Page 4] Internet-Draft SDP O/A for RTP over QUIC September 2021 An 'm' line that specifies 'QUIC' MUST further qualify the application-layer protocol using an fmt identifier, such as "QUIC/RTP/AVPF". Media described using an 'm' line containing the 'QUIC' protocol identifier are carried using QUIC ([RFC9000]). The following is an update to the ABNF for an 'm' line, as specified by [RFC8866], that defines a new value for the QUIC protocol. media-field = %s"m" "=" media SP port \["/" integer\] SP proto 1*(SP fmt) CRLF m= line parameter parameter value(s) ------------------------------------------------------------------ : (unchanged from {{RFC8866}}) : 'QUIC' : UDP port number : (unchanged from {{RFC8866}}) 3.1.2. The QUIC/RTP/SAVP proto The following is an update to the ABNF for an 'm' line, as specified by [RFC8866], that defines a new value for the QUIC/RTP/SAVP protocol. media-field = %s"m" "=" media SP port \["/" integer\] SP proto 1*(SP fmt) CRLF m= line parameter parameter value(s) ------------------------------------------------------------------ : (unchanged from {{RFC8866}}) : 'QUIC/RTP/SAVP' : UDP port number : (unchanged from {{RFC8866}}) 3.1.3. The QUIC/RTP/AVPF proto The following is an update to the ABNF for an 'm' line, as specified by [RFC8866], that defines a new value for the QUIC/RTP/AVPF protocol. Dawkins Expires 12 March 2022 [Page 5] Internet-Draft SDP O/A for RTP over QUIC September 2021 media-field = %s"m" "=" media SP port \["/" integer\] SP proto 1*(SP fmt) CRLF m= line parameter parameter value(s) ------------------------------------------------------------------ : (unchanged from {{RFC8866}}) : 'QUIC/RTP/AVPF' : UDP port number : (unchanged from {{RFC8866}}) 3.1.4. The QUIC/RTP/SAVPF proto The following is an update to the ABNF for an 'm' line, as specified by [RFC8866], that defines a new value for the QUIC/RTP/SAVPF protocol. media-field = %s"m" "=" media SP port \["/" integer\] SP proto 1*(SP fmt) CRLF m= line parameter parameter value(s) ------------------------------------------------------------------ : (unchanged from {{RFC8866}}) : 'QUIC/RTP/SAVPF' : UDP port number : (unchanged from {{RFC8866}}) 3.2. A QUIC/RTP/AVPF Offer A complete example of an SDP offer using QUIC/RTP/AVPF might look like: Dawkins Expires 12 March 2022 [Page 6] Internet-Draft SDP O/A for RTP over QUIC September 2021 +================================+=================================+ | SDP line | Notes | +================================+=================================+ | v=0 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | o=jdoe 3724394400 3724394405 | Same as [RFC8866] | | IN IP4 198.51.100.1 | | +--------------------------------+---------------------------------+ | s=Call to John Smith | Same as [RFC8866] | +--------------------------------+---------------------------------+ | i=SDP Offer #1 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | u=http://www.jdoe.example.com/ | Same as [RFC8866] | | home.html | | +--------------------------------+---------------------------------+ | e=Jane Doe | Same as [RFC8866] | | jane@jdoe.example.com | | | (mailto:jane@jdoe.example.com) | | +--------------------------------+---------------------------------+ | p=+1 617 555-6011 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | c=IN IP4 198.51.100.1 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | t=0 0 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | m=audio 49170 RTP/AVP 0 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | m=audio 49180 RTP/AVP 0 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | m=video 51372 QUIC/RTP/AVPF 99 | QUIC transport | +--------------------------------+---------------------------------+ | a=setup:passive | will wait for QUIC handshake | | | (setup attribute from | | | [RFC4145]) | +--------------------------------+---------------------------------+ | a=connection:new | don't want to reuse an existing | | | QUIC connection (connection | | | attribute from [RFC4145]) | +--------------------------------+---------------------------------+ | c=IN IP6 2001:db8::2 | Same as [RFC8866] | +--------------------------------+---------------------------------+ | a=rtpmap:99 h266/90000 | H.266 VVC codec | | | [I-D.ietf-avtcore-rtp-vvc] | +--------------------------------+---------------------------------+ Table 1 Dawkins Expires 12 March 2022 [Page 7] Internet-Draft SDP O/A for RTP over QUIC September 2021 This example is largely based on an example appearing in [RFC8866], Section 5, but is using QUIC/RTP/AVPF to support a newer codec. Because QUIC uses connections for both streams and datagrams, we are reusing two session- and media-level SDP attributes from [SDP-attribute-name] that were defined in [RFC4145] for use with TCP: setup and connection. This example SDP offer might be included in a SIP Invite. 4. IANA Considerations This document registers these protocols in the proto registry ([SDP-parameters]). * QUIC (Section 3.1.1) * QUIC/RTP/SAVP (Section 3.1.2) * QUIC/RTP/AVPF (Section 3.1.3) * QUIC/RTP/SAVPF (Section 3.1.4) 4.1. Proto Registrations IANA is requested to add these protocols to the Session Description Protocol (SDP) Parameters proto registry ([SDP-parameters]). +=======+================+===========+ | Type | SDP Name | Reference | +=======+================+===========+ | proto | QUIC | RFCXXXX | +-------+----------------+-----------+ | proto | QUIC/RTP/SAVP | RFCXXXX | +-------+----------------+-----------+ | proto | QUIC/RTP/AVPF | RFCXXXX | +-------+----------------+-----------+ | proto | QUIC/RTP/SAVPF | RFCXXXX | +-------+----------------+-----------+ Table 2 *Note to the RFC Editor* Please replace "RFCXXXX" with the assigned RFC number, when that is available, and remove this note. Dawkins Expires 12 March 2022 [Page 8] Internet-Draft SDP O/A for RTP over QUIC September 2021 5. Security Considerations Security considerations for the QUIC protocol are described in the corresponding section in [RFC9000]. Security considerations for the TLS handshake used to secure QUIC are described in [RFC9001]. Security considerations for SDP are described in the corresponding section in [RFC8866]. Security considerations for SDP offer/answer are described in the cooresponding section in [RFC3264]. 6. Acknowledgments My appreciation to the authors of [RFC4145], which served as a model for the initial structure of this document. Your name could appear here. Please comment and contribute, as per Section 1.3. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, June 2002, . [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with Session Description Protocol (SDP)", RFC 3264, DOI 10.17487/RFC3264, June 2002, . [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, . Dawkins Expires 12 March 2022 [Page 9] Internet-Draft SDP O/A for RTP over QUIC September 2021 [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, . [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, "Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, DOI 10.17487/RFC4585, July 2006, . [RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC5124, February 2008, . [RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and Control Packets on a Single Port", RFC 5761, DOI 10.17487/RFC5761, April 2010, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8825] Alvestrand, H., "Overview: Real-Time Protocols for Browser-Based Applications", RFC 8825, DOI 10.17487/RFC8825, January 2021, . [RFC8843] Holmberg, C., Alvestrand, H., and C. Jennings, "Negotiating Media Multiplexing Using the Session Description Protocol (SDP)", RFC 8843, DOI 10.17487/RFC8843, January 2021, . [RFC8866] Begen, A., Kyzivat, P., Perkins, C., and M. Handley, "SDP: Session Description Protocol", RFC 8866, DOI 10.17487/RFC8866, January 2021, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . Dawkins Expires 12 March 2022 [Page 10] Internet-Draft SDP O/A for RTP over QUIC September 2021 [RFC9001] Thomson, M., Ed. and S. Turner, Ed., "Using TLS to Secure QUIC", RFC 9001, DOI 10.17487/RFC9001, May 2021, . [SDP-attribute-name] "SDP Parameters - attribute-name", September 2021, . [SDP-parameters] "SDP Parameters - Proto", September 2021, . 7.2. Informative References [I-D.engelbart-rtp-over-quic] Ott, J. and M. Engelbart, "RTP over QUIC", Work in Progress, Internet-Draft, draft-engelbart-rtp-over-quic- 00, 12 July 2021, . [I-D.ietf-avtcore-rtp-vvc] Zhao, S., Wenger, S., Sanchez, Y., and Y. Wang, "RTP Payload Format for Versatile Video Coding (VVC)", Work in Progress, Internet-Draft, draft-ietf-avtcore-rtp-vvc-10, 9 July 2021, . [I-D.ietf-quic-http] Bishop, M., "Hypertext Transfer Protocol Version 3 (HTTP/3)", Work in Progress, Internet-Draft, draft-ietf- quic-http-34, 2 February 2021, . [RFC4145] Yon, D. and G. Camarillo, "TCP-Based Media Transport in the Session Description Protocol (SDP)", RFC 4145, DOI 10.17487/RFC4145, September 2005, . Author's Address Spencer Dawkins Tencent America LLC United States of America Email: spencerdawkins.ietf@gmail.com Dawkins Expires 12 March 2022 [Page 11]