Session Date/Time: 22 Jul 2025 12:30

scone

Summary

The scone working group meeting in Madrid focused on reviewing the results of the first scone hackathon, discussing the integration of time window durations, and addressing open issues on the scone base protocol, particularly early indication and throughput advice. Applicability and manageability were also discussed, along with potential future interim meetings.

Key Discussion Points

Hackathon Review: The scone hackathon was a success, demonstrating the simplicity and clarity of the current specification, with multiple successful implementations and interoperability tests. Issues found were related to clarifying the need for zero-length values for the SCONE transport parameter and ensuring middleboxes update EDP checks when updating rate guidance.
Time Window Duration: Anup presented lab results on the impact of different time window durations on bitrate measurement and user experience. The recommendation was to consider a longer window (120 seconds) to accommodate different applications and burstiness, though concerns were raised about the utility of such a large window for resource protection and policy enforcement.
Early Indication (Issue #5): A major point of discussion was whether to include an early indication in the protocol to signal scone support, potentially obviating the need for SNI-based detection. Concerns were raised about fingerprinting and the potential for inconsistent policies. A proposed compromise was to encourage endpoints to send scone indications on all quick flows to reduce the fingerprinting risk.
Throughput Advice (Issue #20): The working group discussed what throughput advice means and how the network element and endpoint should measure and enforce this advice. One of the current proposal is to use a sliding window algorithm with a fixed 60 second or 120 second minimum window
Applicability and Manageability: An update was provided on the applicability and manageability draft, focusing on how to deploy and manage scone in real networks. Emphasis was placed on reviewing the draft and incorporating relevant GitHub issues.

Decisions and Action Items

Early Indication: The working group tentatively agreed to include a first packet client indication of scone support in the protocol. The specific mechanisms and deployment considerations will be further discussed on the mailing list and captured in a PR.
Throughput Advice: The discussion on average window size, measurement types (block vs. sliding), and conformance behavior will continue on the mailing list, with an updated PR.
Applicability and Manageability Draft: Continue development of draft. Aim for better interoperability.
Interim Meetings:
- Schedule one interim meeting focused on interop and hackathon planning for Montreal.
- Schedule one or two more interim meetings to discuss issues more feverishly, particularly early indication.

Next Steps

Post PR with early indication mechanisms and discussion of related deployment considerations.
Continue discussion on mailing list for best way to measure throughput
Develop next steps for applicability and manageability.
Schedule two (or three?) interim meetings, one focused on planning for Montreal interop.