rfc-substrate-awareness.md — Document Summary#
Identifier: TFAWG-0001 · Status: Draft · Category: Informational · Date: 2026-07-02
Abstract#
Defines Substrate-Aware Transport Services (SATS) — an extension framework layering EIS substrate-consciousness onto the IETF TAPS transport model (RFC 8095 / RFC 8923), with HTTP-level field extensions aligned to RFC 9110.
Section Coverage#
| § | Title | Key Content |
|---|---|---|
| 1 | Introduction | Problem framing; four SATS deliverables (SATS framework, SCO, IPR Negotiation, HTTP extensions) |
| 2 | Conventions & Definitions | RFC 2119 key words; full glossary: EIS, SATS, SCO, RTT-Budget, IPR, Traversal Vector, Fidelity Grade |
| 3 | Motivation | RFC 8923 gaps for enterprise identity; RTT/Inside as the two primary SATS axes |
| 4 | EIS Substrate Model | Full Layer 0–8 table (Symbol, Name, Description); canonical RTT budgets, reliability, ordering, and loss tolerance per layer; traversal semantics (ascending, descending, lateral, non-contiguous) |
| 5 | Substrate Metadata | SCO structure (CBOR + Structured Fields); LayerToken encoding; Traversal Vector construction rules; Fidelity Grade formula (W_rtt × f_rtt × W_loss × f_loss × W_relay × f_relay × W_order × f_order) |
| 6 | Transport-Service Extensions | RFC 8095/8923 anchoring; four SATS features: sats-rtt-budget (advisory/soft/hard enforcement), Inside-Path Relay Negotiation (IPR discovery via /.well-known/sats-relays, RelayHop structure), sats-ordering-contract (layer-transition ordering), sats-reliability (fidelity-graded with fallback/abort escalation) |
| 7 | HTTP-Level Extensions | 5 request fields (Substrate-Layer, Substrate-Context, Substrate-RTT-Budget, Substrate-Traversal, Substrate-Domain); 3 response fields; 2 trailer fields; 5 custom status codes (560–564); sats-layer media type parameter + Accept-Substrate |
| 8 | Examples | Five annotated exchanges: L0 bootstrap, L3 identity assertion with RTT budget, L6 semantic payload relay with trailer, non-contiguous 0→4→8 traversal, HTTP/2 push with substrate trailer |
| 9 | Security Considerations | SCO spoofing, RTT exhaustion attacks, IPR trust model, header injection, downgrade/strip attacks, SCO privacy requirements |
| 10 | IANA Considerations | Three registries: HTTP Header Fields (11 entries), Transport Error Codes (0x5A01–0x5A07), Layer Profile weights and minimum fidelity thresholds |
| 11–12 | References | Normative: RFC 2119, 8174, 8095, 8923, 9110, 8941, 8949, 4648 · Informative: RFC 8303, 9112, 9113, 9114, 8922, TAPS-ARCH |