Summary of S4-260102: Introduction to TR 26.836 on QUIC-based Media Delivery

Document Overview

This contribution provides the foundational introduction for TR 26.836, which addresses the study item FS_Q4RTC_MED approved in SA#110. The objective is to identify and document existing and emerging QUIC-based media delivery protocols suitable for real-time communication.

Main Technical Contributions

1. QUIC Protocol Foundation

The document establishes the baseline understanding of QUIC by referencing the core IETF specifications:

• RFC 9000: Core QUIC transport mechanisms (UDP-based, multiplexed, secure)
• RFC 9001: TLS 1.3 integration for security
• RFC 9002: Loss detection and congestion control
• RFC 8999: Version-independent properties

Additional extensions and operational specifications are referenced:
- RFC 9114: HTTP/3
- RFC 9221: Unreliable datagram extension
- RFC 9309: Applicability guidance
- RFC 9312: Manageability aspects

2. Key Motivations for QUIC in Media Transport

The contribution identifies several technical advantages of QUIC for media delivery:

Lower Latency and Faster Start-up

• 1-RTT handshake with optional 0-RTT resumption reduces join time
• User-space pacing algorithms minimize burstiness and reduce jitter

Independent Stream Processing and Prioritization

• Eliminates head-of-line (HoL) blocking across different streams
• Prevents one stalled media flow from blocking others (e.g., video frame not blocking audio)
• Stream prioritization enables resource allocation based on application-signaled importance

Selective Reliability

• Datagrams (RFC 9221): Best-effort delivery for latency-critical applications requiring unordered, unreliable packet delivery
• Streams: Reliable, ordered delivery with explicit prioritization
• Applications can mix both approaches based on data criticality and delay sensitivity

Always-on Security

• Built-in TLS 1.3 encryption and authentication eliminates need for separate DTLS layer
• Connection IDs (CIDs) and encrypted headers improve privacy
• Resilience to middlebox ossification

Better Mobility and Robustness

• Connection migration enables seamless IP/port changes (e.g., Wi-Fi to cellular transitions)
• Avoids call drops and renegotiations that disrupt audio/video continuity

3. IETF QUIC-based Application Protocols

The document identifies three QUIC-based application protocols under IETF standardization for real-time and interactive communication:

• MOQT (Media over QUIC Transport): draft-ietf-moq-transport-16
• ROQ (RTP over QUIC): draft-ietf-avtcore-rtp-over-quic-14
• WebTransport: draft-ietf-webtrans-overview-11

4. Normative References

The contribution adds comprehensive normative references covering:
- Core QUIC specifications (RFCs 8999, 9000, 9001, 9002)
- QUIC extensions (RFCs 9114, 9221)
- QUIC operational guidance (RFCs 9309, 9312)
- Security foundation (RFC 8446 - TLS 1.3)
- IETF work-in-progress drafts for MOQT, ROQ, and WebTransport

Document Structure

The changes propose additions to:
- Clause 1 (Introduction): Complete technical introduction to QUIC and its benefits for media transport
- Clause 2 (References): Addition of 12 new normative references ([y1] through [y12])