SCONE TCP Option#

Wesley Eddy, Matt Joras (Meta) — individual draft in TCPM

• Why: A different direction of network→endpoint signaling than FANTEL: instead of telling the ingress to reroute, middleboxes tell endpoints their rate limits. Interesting precisely because it parallels the AI-fabric notification philosophy (network signals, endpoints adapt) in an entirely different problem space — and shows the SCONE WG's charter spilling beyond QUIC.
• What: A TCP option that network elements can insert or modify to give endpoints throughput guidance — motivated by rate-limiting of ABR video in mobile networks, where knowing the limit lets the player pick a compliant rendition instead of oscillating through losses.
• How: Explicitly modeled on MSS clamping — an on-path element rewrites an option the downstream stack can act on; the same network elements being built for QUIC SCONE (a new QUIC packet type carrying rate-limit encodings middleboxes can read and set) would handle the TCP option. Many details open: application interfaces, interaction with other TCP options, send timing, insertion rules.
• Where applicable: Rate-limited access networks (mobile) with adaptive video; the rate-signaling mechanism itself is general. Very early individual draft (-00) gauging whether TCPM wants this at all — a "watch the question, not the draft" item.