RTP over QUIC
draft-engelbart-rtp-over-quic-01
The information below is for an old version of the document.
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|---|---|---|---|
| Authors | Joerg Ott , Mathis Engelbart | ||
| Last updated | 2021-10-25 (Latest revision 2021-07-12) | ||
| Replaced by | draft-ietf-avtcore-rtp-over-quic, draft-ietf-avtcore-rtp-over-quic | ||
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draft-engelbart-rtp-over-quic-01
Network Working Group J. Ott
Internet-Draft M. Engelbart
Intended status: Informational Technical University Munich
Expires: 28 April 2022 25 October 2021
RTP over QUIC
draft-engelbart-rtp-over-quic-01
Abstract
This document specifies a minimal mapping for encapsulating RTP and
RTCP packets within QUIC. It also discusses how to leverage state
from the QUIC implementation in the endpoints to reduce the exchange
of RTCP packets.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the mailing list (), which
is archived at .
Source for this draft and an issue tracker can be found at
https://github.com/mengelbart/rtp-over-quic-draft.
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 28 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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
2. Terminology and Notation . . . . . . . . . . . . . . . . . . 3
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4
4. Local Interfaces . . . . . . . . . . . . . . . . . . . . . . 5
4.1. QUIC Interface . . . . . . . . . . . . . . . . . . . . . 5
4.2. Congestion Controller Interface . . . . . . . . . . . . . 5
4.3. Codec Interface . . . . . . . . . . . . . . . . . . . . . 6
5. Packet Format . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Protocol Operation . . . . . . . . . . . . . . . . . . . . . 7
7. SDP Signalling . . . . . . . . . . . . . . . . . . . . . . . 9
8. Used RTP/RTCP packet types . . . . . . . . . . . . . . . . . 11
9. Enhancements . . . . . . . . . . . . . . . . . . . . . . . . 12
10. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1. Impact of Connection Migration . . . . . . . . . . . . . 12
11. Security Considerations . . . . . . . . . . . . . . . . . . . 12
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
13.1. Normative References . . . . . . . . . . . . . . . . . . 12
13.2. Informative References . . . . . . . . . . . . . . . . . 15
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
The Real-time Transport Protocol (RTP) [RFC3550] is generally used to
carry real-time media for conversational media sessions, such as
video conferences, across the Internet. Since RTP requires real-time
delivery and is tolerant to packet losses, the default underlying
transport protocol has been UDP, recently with DTLS on top to secure
the media exchange and occasionally TCP (and possibly TLS) as
fallback. With the advent of QUIC and, most notably, its unreliable
DATAGRAM extension, another secure transport protocol becomes
available. QUIC and its DATAGRAMs combine desirable properties for
real-time traffic (e.g., no unnecessary retransmissions, avoiding
head-of-line blocking) with a secure end-to-end transport that is
also expected to work well through NATs and firewalls.
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Moreover, with QUIC's multiplexing capabilities, reliable and
unreliable transport connections as, e.g., needed for WebRTC, can be
established with only a single port used at either end of the
connection. This document defines a mapping of how to carry RTP over
QUIC. The focus is on RTP and RTCP packet mapping and on reducing
the amount of RTCP traffic by leveraging state information readily
available within a QUIC endpoint. This document also briefly touches
upon how to signal media over QUIC using the Session Description
Protocol (SDP) [RFC8866].
The scope of this document is limited to unicast RTP/RTCP.
Note that this draft is similar in spirit to but differs in numerous
ways from [QRT].
2. Terminology and Notation
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.
The following terms are used:
Congestion Controller: QUIC specifies a congestion controller in
Section 7 of [RFC9002], but the specific requirements for
interactive real-time media, lead to the development of dedicated
congestion control algorithms. The term congestion controller in
this document refers to these algorithms which are dedicated to
real-time applications and may be used next to or instead of the
congestion controller specified by [RFC9002].
Datagram: Datagrams exist in UDP as well as in QUICs unreliable
datagram extension. If not explicitly noted differently, the term
datagram in this document refers to a QUIC Datagram as defined in
[QUIC-DATAGRAM].
Endpoint: A QUIC server or client that participates in an RTP over
QUIC session.
Frame: A QUIC frame as defined in [RFC9000].
Media Encoder: An entity that is used by an application to produce a
stream of encoded media, which can be packetized in RTP packets to
be transmitted over QUIC.
Receiver: An endpoint that receives media in RTP packets and may
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send or receive RTCP packets.
Sender: An endpoint sends media in RTP packets and may send or
receive RTCP packets.
Packet diagrams in this document use the format defined in
Section 1.3 of [RFC9000] to illustrate the order and size of fields.
3. Protocol Overview
This document introduces a mapping of the Real-time Transport
Protocol (RTP) to the QUIC transport protocol. QUIC supports two
transport methods: reliable streams and unreliable datagrams
[RFC9000], [QUIC-DATAGRAM]. RTP over QUIC uses unreliable QUIC
datagrams to transport real-time data.
[RFC3550] specifies that RTP sessions need to be transmitted on
different transport addresses to allow multiplexing between them.
RTP over QUIC uses a different approach, in order to leverage the
advantages of QUIC connections without managing a separate QUIC
connection per RTP session. QUIC does not provide demultiplexing
between different flows on datagrams, but suggests that an
application implements a demultiplexing mechanism if it is required.
An example of such a mechanism are flow identifiers prepended to each
datagram frame as described in [H3-DATAGRAM]. RTP over QUIC uses a
flow identifier as a replacement for network address and port number,
to multiplex many RTP sessions over the same QUIC connection.
A congestion controller can be plugged in, to adapt the media bitrate
to the available bandwidth. This document does not mandate any
congestion control algorithm, some examples include Network-Assisted
Dynamic Adaptation (NADA) [RFC8698] and Self-Clocked Rate Adaptation
for Multimedia (SCReAM) [RFC8298]. These congestion control
algorithms require some feedback about the performance of the network
in order to calculate target bitrates. Traditionally this feedback
is generated at the receiver and sent back to the sender via RTCP.
Since QUIC also collects some metrics about the networks performance,
these metrics can be used to generate the required feedback at the
sender-side and provide it to the congestion controller, to avoid the
additional overhead of the RTCP stream.
*Editor's note:* Should the congestion controller work
independently from the congestion controller used in QUIC, because
the QUIC connection can simultaneously be used for other data
streams, that need to be congestion controlled, too?
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4. Local Interfaces
RTP over QUIC requires different components like QUIC
implementations, congestion controllers and media encoders to work
together. The interfaces of these components have to fulfill certain
requirements which are described in this section.
4.1. QUIC Interface
If the used QUIC implementation is not directly incorporated into the
RTP over QUIC mapping implementation, it has to fulfill the following
interface requirements. The QUIC implementation MUST support QUICs
unreliable datagram extension and it MUST provide a way to signal
acknowledgments or losses of QUIC datagrams to the application.
Since datagram frames cannot be fragmented, the QUIC implementation
MUST provide a way to query the maximum datagram size, so that an
application can create RTP packets that always fit into a QUIC
datagram frame.
Additionally, a QUIC implementation MUST expose the recorded RTT
statistics as described in Section 5 of [RFC9002] to the application.
These statistics include the latest generated RTT sample
(latest_rtt), the minimum observed RTT over a period of time
(min_rtt), exponentially-weighted moving average (smoothed_rtt) and
the mean deviation (rtt_var). These values are necessary to perform
congestion control as explained in Section 4.2.
Section 7.1 of [RFC9002] also specifies how QUIC treats Explicit
Congestion Notifications (ECN) if it is supported by the network
path. If ECN counts can be exported from a QUIC implementation,
these may be used to improve congestion control, too.
4.2. Congestion Controller Interface
There are different congestion control algorithms proposed by RMCAT
to implement application layer congestion control for real-time
communications. To estimate the currently available bandwidth, these
algorithms keep track of the sent packets and typically require a
list of successfully delivered packets together with the timestamps
at which they were received by a receiver. The bandwidth estimation
can then be used to decide, whether the media encoder can be
configured to produce output at a higher or lower rate.
A congestion controller used for RTP over QUIC should be able to
compute an adequate bandwidth estimation using the following inputs:
* t_current: A current timestamp
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* pkt_status_list: A list of RTP packets that were acknowledged by
the receiver
* pkt_delay_list: For each acknowledged RTP packet, a delay between
the send- and receive-timestamps of the packet
* The RTT estimations calculated by QUIC as described in Section 5
of [RFC9002]:
- latest_rtt: The latest RTT sample generated by QUIC.
- min_rtt: The miminum RTT observed by QUIC over a period of time
- smoothed_rtt: An exponentially-weighted moving average of the
observed RTT values
- rtt_var: The mean deviation in the observed RTT values
* ecn: Optionally ECN marks may be used, if supported by the network
and exposed by the QUIC implementation.
A congestion controller MUST expose a target_bitrate to which the
encoder should be configured to fully utilize the available
bandwidth.
It is assumed that the congestion controller provides a pacing
mechanism to determine when a packet can be send and to avoid bursts.
All of the currently proposed congestion control algorithms for real-
time communications provide such a pacing mechanism. The use of
congestion controllers which don't provide a pacing mechanism is out
of scope of this document.
4.3. Codec Interface
An application is expected to adapt the media bitrate to the observed
available bandwidth by setting the media encoder to the
target_bitrate that is computed by the congestion controller. Thus,
the media encoder needs to offer a way to update its bitrate
accordingly. An RTP over QUIC implementation can either expose the
most recent target_bitrate produced by the congestion controller to
the application, or accept a callback from the application, which
updates the encoder bitrate whenever the congestion controller
updates the target_bitrate.
5. Packet Format
All RTP and RTCP packets MUST be sent in QUIC datagram frames with
the following format:
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Datagram Payload {
Flow Identifier (i),
RTP/RTCP Packet (..)
}
Figure 1: Datagram Payload Format
For multiplexing RTP sessions on the same QUIC connection, each RTP/
RTCP packet is prefixed with a flow identifier. This flow identifier
serves as a replacement for using different transport addresses per
session. A flow identifier is a QUIC variable length integer which
must be unique per stream.
RTP and RTCP packets of a single RTP session MAY be sent using the
same flow identifier (following the procedures defined in [RFC5761],
or they MAY be sent using different flow identifiers. The respective
mode of operation MUST be indicated using the appropriate signaling,
e.g., when using SDP as discussed in Section 7.
RTP and RTCP packets of different RTP sessions MUST be sent using
different flow identifiers.
Differentiating RTP/RTCP datagrams of different RTP sessions from
non-RTP/RTCP datagrams is the responsibility of the application by
means of appropriate use of flow identifiers and the corresponding
signaling.
Senders SHOULD consider the header overhead associated with QUIC
datagrams and ensure that the RTP/RTCP packets including their
payloads, QUIC, and IP headers will fit into path MTU.
6. Protocol Operation
This section describes how senders and receivers can exchange RTP and
RTCP packets using QUIC. While the receiver side is very simple, the
sender side has to keep track of sent packets and corresponding
acknowledgments to implement congestion control.
RTP/RTCP packets that are submitted to an RTP over QUIC
implementation are buffered in a queue. The congestion controller
defines the rate at which the next packet is dequeued and sent over
the QUIC connection. Before a packet is sent, it is prefixed with
the flow identifier described in Section 5 and encapsulated in a QUIC
datagram.
The implementation has to keep track of sent RTP packets in order to
build the feedback for a congestion controller described in
Section 4.2. Each sent RTP packet is mapped to the datagram in which
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it was sent over QUIC. When the QUIC implementation signals an
acknowledgment for a specific datagram, the packet that was sent in
this datagram is marked as received. Together with the received
mark, an estimation of the delay at which the packet was received by
the peer can be stored. Assuming the RTT is divided equally between
the link from the sender to the receiver and the link back to the
sender, this estimation can be calculated by adding the latest_rtt
divided by two to the send time of the datagram in which the RTP
packet was sent. This mapping can later be used to create the
pkt_status_list and the pkt_delay_list as described in Section 4.2.
In a regular interval, the pkt_status_list and the pkt_delay_list
MUST be passed to the congestion controller together with the current
timestamp t_current and the RTT statistics min_rtt, smoothed_rtt and
rtt_var. If available, the feedback MAY also contain the ECN marks.
The feedback report can be passed to the congestion controller at a
frequency specified by the used algorithm.
The congestion controller regularly outputs the target_bitrate, which
is forwarded to the encoder using the interface described in
Section 4.3.
+------------+ Media +-------------+
| Encoder |------->| Application |
| | | |
+------------+ +-------------+
^ |
| |
| Set RTP/ |
| Target RTCP |
| bitrate |
| v Target
| +-------------+ Bitrate +-------------+
+---------------| RTP over |<----------| Congestion |
| QUIC | Feedback | Controller |
+-------------+---------->+-------------+
| ^
Flow ID | | Datagram
prefixed | | ACK/Lost-
RTP/RTCP | | notification
packets | | +
| | RTT
v |
+-------------+
| QUIC |
| |
+-------------+
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Figure 2: RTP over QUIC send flow
On receiving a datagram, an RTP over QUIC implementation strips off
and parses the flow identifier to identify the stream to which the
received RTP or RTCP packet belongs. The remaining content of the
datagram is then passed to the RTP session which was assigned the
given flow identifier.
7. SDP Signalling
QUIC is a connection-based protocol that supports connectionless
transmissions of DATAGRAM frames within an established connection.
As noted above, demultiplexing DATAGRAMS intended for different
purposes is up to the application using QUIC.
There are several necessary steps to carry out jointly between the
communicating peers to enable RTP over QUIC:
1. The protocol identifier for the m= lines MUST be "QUIC/RTP",
combined as per [RFC8866] with the respective audiovisual
profile: for example, "QUIC/RTP/AVP".
2. The peers need to decide whether to establish a new QUIC
connection or whether to re-use an existing one. In case of
establishing a new connection, the initiator and the responder
(client and server) need to be determined. Signaling for this
step MUST follow [RFC8122] on SDP attributes for connection-
oriented media for the a=setup, a=connection, and a=fingerprint
attributes. They MUST use the appropriate protocol
identification as per 1.
3. The peers must provide a means for identifying RTP sessions
carried in QUIC DATAGRAMS. To enable using a common transport
connection for one, two, or more media sessions in the first
place, the BUNDLE grouping framework MUST be used [RFC8843]. All
media sections belonging to a bundle group, except the first one,
MUST set the port in the m= line to zero and MUST include the
a=bundle-only attribute.
For disambiguating different RTP session, a reference needs to be
provided for each m= line to allow associating this specific
media session with a flow identifier. This could be achieved
following different approaches:
* Simply reusing the a=extmap attribute [RFC8285] and relying on
RTP header extensions for demultiplexing different media
packets carried in QUIC DATAGRAM frames.
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* Defining a variant or different flavor of the a=extmap
attribute [RFC8285] that binds media sessions to flow
identifiers used in QUIC DATAGRAMS.
*Editor's note:* It is likely preferable to use multiplexing
using QUIC DATAGRAM flow identifiers because this multiplexing
mechanisms will also work across RTP and non-RTP media
streams.
In either case, the corresponding identifiers MUST be treated
independently for each direction of transmission, so that an
endpoint MAY choose its own identifies and only uses SDP to
inform its peer which RTP sessions use which identifiers.
To this end, SDP MUST be used to indicate the respective flow
identifiers for RTP and RTCP of the different RTP sessions (for
which we borrow inspiration from [RFC3605]).
4. The peers MUST agree, for each RTP session, whether or not to
apply RTP/RTCP multiplexing. If multiplexing RTP and RTCP shall
take place on the same flow identifier, this MUST be indicated
using the attribute a=rtcp-mux.
A sample session setup offer (liberally borrowed and extended from
[RFC8843] and [RFC8122] could look as follows:
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v=0
o=alice 2890844526 2890844526 IN IP6 2001:db8::3
s=
c=IN IP6 2001:db8::3
t=0 0
a=group:BUNDLE abc xyz
m=audio 10000 QUIC/RTP/AVP 0 8 97
a=setup:actpass
a=connection:new
a=fingerprint:SHA-256 \
12:DF:3E:5D:49:6B:19:E5:7C:AB:4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF: \
3E:5D:49:6B:19:E5:7C:AB:4A:AD
b=AS:200
a=mid:abc
a=rtcp-mux
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC/8000
a=extmap:1 urn:ietf:params:<tbd>
m=video 0 QUIC/RTP/AVP 31 32
b=AS:1000
a=bundle-only
a=mid:bar
a=rtcp-mux
a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000
a=extmap:2 urn:ietf:params:<tbd>
Figure 3: SDP Offer
Signaling details to be worked out.
8. Used RTP/RTCP packet types
Any RTP packet can be sent over QUIC and no RTCP packets are used by
default. Since QUIC already includes some features which are usually
implemented by certain RTCP messages, RTP over QUIC implementations
should not need to implement the following RTCP messages:
* PT=205, FMT=1, Name=Generic NACK: Provides Negative
Acknowledgments [RFC4585]. Acknowledgment and loss notifications
are already provided by the QUIC connection.
* PT=205, FMT=8, Name=RTCP-ECN-FB: Provides RTCP ECN Feedback
[RFC6679]. If supported, ECN may directly be exposed by the used
QUIC implementation.
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* PT=205, FMT=11, Name=CCFB: RTP Congestion Control Feedback which
contains receive marks, timestamps and ECN notifications for each
received packet [RFC8888]. This can be inferred from QUIC as
described in Section 6.
* PT=210, FMT=all, Name=Token, [RFC6284] specifies a way to
dynamically assign ports for RTP receivers. Since QUIC
connections manage ports on their own, this is not required for
RTP over QUIC.
9. Enhancements
The RTT statistics collected by QUIC may not be very precise because
it can be influenced by delayed ACKs. An alternative to the RTT is
to explicitly measure a one way delay. [QUIC-TS] suggests an
extension for QUIC to implement one way delay measurements using a
timestamp carried in a special QUIC frame. The new frame carries the
time at which a packet was sent. This timestamp can be used by the
receiver to estimate a one way delay as the difference between the
time at which a packet was received and the timestamp in the received
packet. The one way delay can then be used as a replacement for the
receive time estimation derived from the RTT as described in
Section 6 to create the pkt_delay_list.
*Editor's note:* Even with one-way delay measurements it is still
not possible to identify exact timestamps for individual packets,
since the timestamp may be sent with an ACK that acks more than
one earlier packet.
10. Discussion
10.1. Impact of Connection Migration
11. Security Considerations
TBD
12. IANA Considerations
This document has no IANA actions.
13. References
13.1. Normative References
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[H3-DATAGRAM]
Schinazi, D., Ed., "Using QUIC Datagrams with HTTP/3",
Work in Progress, Internet-Draft, draft-schinazi-quic-h3-
datagram-05, <https://datatracker.ietf.org/doc/html/draft-
schinazi-quic-h3-datagram-05>.
[QUIC-DATAGRAM]
Pauly, T., Ed., Kinnear, E., Ed., and D. Schinazi, Ed.,
"An Unreliable Datagram Extension to QUIC", Work in
Progress, Internet-Draft, draft-ietf-quic-datagram-02,
<https://datatracker.ietf.org/doc/html/draft-ietf-quic-
datagram-02>.
[QUIC-TS] Huitema, C., Ed., "Quic Timestamps For Measuring One-Way
Delays", Work in Progress, Internet-Draft, draft-huitema-
quic-ts-05, <https://datatracker.ietf.org/doc/html/draft-
huitema-quic-ts-05>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[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, <https://www.rfc-editor.org/rfc/rfc3550>.
[RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute
in Session Description Protocol (SDP)", RFC 3605,
DOI 10.17487/RFC3605, October 2003,
<https://www.rfc-editor.org/rfc/rfc3605>.
[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,
<https://www.rfc-editor.org/rfc/rfc4585>.
[RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
Control Packets on a Single Port", RFC 5761,
DOI 10.17487/RFC5761, April 2010,
<https://www.rfc-editor.org/rfc/rfc5761>.
[RFC6284] Begen, A., Wing, D., and T. Van Caenegem, "Port Mapping
between Unicast and Multicast RTP Sessions", RFC 6284,
DOI 10.17487/RFC6284, June 2011,
<https://www.rfc-editor.org/rfc/rfc6284>.
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[RFC6679] Westerlund, M., Johansson, I., Perkins, C., O'Hanlon, P.,
and K. Carlberg, "Explicit Congestion Notification (ECN)
for RTP over UDP", RFC 6679, DOI 10.17487/RFC6679, August
2012, <https://www.rfc-editor.org/rfc/rfc6679>.
[RFC8122] Lennox, J. and C. Holmberg, "Connection-Oriented Media
Transport over the Transport Layer Security (TLS) Protocol
in the Session Description Protocol (SDP)", RFC 8122,
DOI 10.17487/RFC8122, March 2017,
<https://www.rfc-editor.org/rfc/rfc8122>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8285] Singer, D., Desineni, H., and R. Even, Ed., "A General
Mechanism for RTP Header Extensions", RFC 8285,
DOI 10.17487/RFC8285, October 2017,
<https://www.rfc-editor.org/rfc/rfc8285>.
[RFC8298] Johansson, I. and Z. Sarker, "Self-Clocked Rate Adaptation
for Multimedia", RFC 8298, DOI 10.17487/RFC8298, December
2017, <https://www.rfc-editor.org/rfc/rfc8298>.
[RFC8698] Zhu, X., Pan, R., Ramalho, M., and S. Mena, "Network-
Assisted Dynamic Adaptation (NADA): A Unified Congestion
Control Scheme for Real-Time Media", RFC 8698,
DOI 10.17487/RFC8698, February 2020,
<https://www.rfc-editor.org/rfc/rfc8698>.
[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,
<https://www.rfc-editor.org/rfc/rfc8843>.
[RFC8866] Begen, A., Kyzivat, P., Perkins, C., and M. Handley, "SDP:
Session Description Protocol", RFC 8866,
DOI 10.17487/RFC8866, January 2021,
<https://www.rfc-editor.org/rfc/rfc8866>.
[RFC8888] Sarker, Z., Perkins, C., Singh, V., and M. Ramalho, "RTP
Control Protocol (RTCP) Feedback for Congestion Control",
RFC 8888, DOI 10.17487/RFC8888, January 2021,
<https://www.rfc-editor.org/rfc/rfc8888>.
Ott & Engelbart Expires 28 April 2022 [Page 14]
Internet-Draft RTP over QUIC October 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,
<https://www.rfc-editor.org/rfc/rfc9000>.
[RFC9002] Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection
and Congestion Control", RFC 9002, DOI 10.17487/RFC9002,
May 2021, <https://www.rfc-editor.org/rfc/rfc9002>.
13.2. Informative References
[QRT] Hurst, S., Ed., "QRT: QUIC RTP Tunnelling", Work in
Progress, Internet-Draft, draft-hurst-quic-rtp-tunnelling-
01, <https://datatracker.ietf.org/doc/html/draft-hurst-
quic-rtp-tunnelling-01>.
Acknowledgments
TODO acknowledge.
Authors' Addresses
Jörg Ott
Technical University Munich
Email: ott@in.tum.de
Mathis Engelbart
Technical University Munich
Email: mathis.engelbart@gmail.com
Ott & Engelbart Expires 28 April 2022 [Page 15]