SCONE - IETF 125 Meeting Minutes

Summary

The SCONE working group met at IETF 125 to discuss the progression of its core specifications and explore new applicability scenarios. The primary focus was the status of draft-ietf-scone-protocol following its Working Group Last Call (WGLC) and the refinement of draft-ietf-scone-applicability-manageability. The group established a target to have both documents ready for publication by IETF 126 (Vienna), supported by a "2x2x2" interoperability goal (two independent implementations of network elements, servers, and clients). Technical discussions also covered SCONE's role in Wi-Fi networks, potential extensions for MASQUE, and using SCONE’s versioning model for explicit network measurements.

Key Discussion Points

Working Group Status and Protocol Update

Presenter: Martin Duke Slides: Chairs Slides

draft-ietf-scone-protocol Status: The document has completed WGLC. It is currently in a "waiting for implementation experience" state.
PR 144 (Multiple SCONE Packets): Martin Duke discussed a normative change regarding multiple SCONE packets in a single datagram. The decision is that network elements should only update the first packet; subsequent packets should be ignored. Endpoints are free to drop such datagrams, but should not terminate the connection to prevent Denial of Service (DoS) vectors.
Interoperability Goals: Brian Trammell suggested a "2x2x2" rule (two independent network elements, servers, and clients) with at least one intended for production. Marcus Ihlar noted that interop testing (e.g., Ericsson and Meta) has already demonstrated chained network elements and mobile app integration.
Timeline: There was a strong consensus to target IESG publication by IETF 126 (Vienna).

Applicability and Manageability

Presenter: Zaheduzzaman Sarker Slides: SCONE applicability and manageability draft update and SCONE applicability placement discussion

draft-ietf-scone-applicability-manageability Update: Version -01 includes reordered sections and aligned terminology with the base protocol.
Structural Debate: The group discussed whether to merge this draft into the base protocol or keep it separate.
- Marcus Ihlar and Martin Duke initially considered merging to ensure visibility.
- Mirja Kühlewind and Zaheduzzaman Sarker argued for keeping them separate to avoid delaying the base protocol and to target different audiences (implementers vs. operators).
Content: Mirja Kühlewind emphasized including the relationship between SCONE and L4S. Dan Druta suggested adding more detail on access network changes (e.g., handovers between Wi-Fi and 5G).
Liaison Update: Zaheduzzaman Sarker provided an update on 3GPP SA2, noting that support for SCONE has been incorporated into 3GPP Release 19 (Technical Enhancement TI20). This creates a timeline dependency for the IETF to finalize the protocol.

SCONE for Wi-Fi

Presenter: Sri Gundavelli Slides: SCONE Rate Guidance for Wi-Fi

Wi-Fi Context: Discussed applicability for 802.11 networks where the air interface is the bottleneck. The SCONE Network Element (NE) could be co-located with the Access Point (AP) or a Wireless LAN Controller (WLC).
Rate Calculation: Sri Gundavelli noted that Wi-Fi rate guidance should consider MCS (Modulation and Coding Scheme), channel load, and interference.
Symmetry: There was a brief discussion on symmetric (uplink and downlink) signaling. While SCONE focuses on downlink, Sri Gundavelli advocated for the value of uplink signals at the transport/QUIC layer rather than the application layer.

MASQUE and Explicit Measurements

Presenter: Marcus Ihlar Slides: SCONE-MASQUE and Application of Explicit Measurement Techniques for QUIC Troubleshooting

SCONE-MASQUE: Marcus Ihlar presented an extension to signal throughput advice via MASQUE capsules. Lucas Pardue and Christian Huitema questioned the need for a new capsule if standard SCONE signaling already works for UDP/IP proxying. The topic was parked to see if the base SCONE protocol meets MASQUE needs first.
Explicit Measurements: Marcus Ihlar shared a concept using the SCONE long-header versioning model to expose RTT and packet loss bits (per RFC 9506) to the network. This avoids consuming restricted bits in the QUIC short header. Christian Huitema suggested this might eventually warrant its own BoF if interest persists.

Decisions and Action Items

Decision: Accept PR 144 for draft-ietf-scone-protocol: Network elements will only update the first SCONE packet in a datagram; others are ignored/dropped.
Action Item: Chairs to schedule an interim meeting in late April or early May to specifically refine draft-ietf-scone-applicability-manageability.
Action Item: Gorry Fairhurst to share Ops Area guidance on applicability documents with the mailing list.
Action Item: Sri Gundavelli and co-authors to continue refining Wi-Fi applicability considerations, potentially contributing an example rate calculation algorithm.

Next Steps

Maintain the "waiting for implementation experience" status for draft-ietf-scone-protocol while periodically updating the ID with editorial fixes from GitHub.
Target Working Group Last Call for draft-ietf-scone-applicability-manageability prior to IETF 126.
Drive toward simultaneous submission of both active drafts to the IESG by the Vienna meeting.

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