TTEthernet / SAE AS6802¶

Time-triggered Ethernet profile supporting time-triggered, rate-constrained, and best-effort traffic classes.

Identity¶

Time-triggered Ethernet profile supporting time-triggered, rate-constrained, and best-effort traffic classes.

What This Protocol Teaches¶

• TTEthernet is Ethernet with a metronome and a safety case.
• It teaches how to inspect time-triggered traffic, rate-constrained traffic, best-effort traffic without mistaking field extraction for meaning.
• It keeps observer inference separate from system truth.

Operational Context¶

TTEthernet / SAE AS6802 appears in aviation, spacecraft, industrial contexts and is modeled in the atlas at the data-link, network, schedule layer(s). The binder treats it as an inspection surface: what evidence appears, what timing matters, and what outside authority is required before assigning meaning.

draft-structure-only: this is not yet a final-copy binder page. It has an atlas-grounded teaching hook and source notes, but still needs a stronger worked trace, page-specific ambiguity case, and reviewer-validated visual before promotion.

A Concrete Artifact¶

# synthetic TTEthernet observation
class=TT virtual-link=0x41 cycle=1024 seq=17 len=96

Synthetic offline sample for explanation; not a real operational trace or live-system instruction.

Worked Decode¶

1. Read class=TT as a synthetic time-triggered class cue, not as conformance proof.
2. virtual-link=0x41 names a traffic-shaping context only after a configuration source supports it.
3. cycle=1024 and seq=17 provide timing/order evidence for observer reasoning.
4. len=96 is frame-size evidence; payload meaning remains outside this docs-only page.

Field Layout / Anatomy¶

Visual Model¶

Timing And Authority¶

Timing and authority depend on the deterministic-ethernet-profile role: scheduled, polled, arbitrated, transmitted, or logged evidence should not be read as the same kind of truth. Semantic authority is external to the raw artifact unless the artifact is itself a description or capture format; even then, provenance determines whether the description should be trusted.

Bytes rarely explain themselves. Name the source that defines meaning before naming engineering values: standard metadata, label table, DBC, PGN/SPN definition, object dictionary, register map, DID catalog, LDF, ARXML, channel metadata, or vendor profile.

Failure And Ambiguity¶

• A TT-class label without configuration does not prove schedule membership.
• Sequence gaps may reflect capture loss, redundancy handling, or actual missing traffic.
• Virtual-link names are configuration authority, not raw-frame truth.

Observer Lesson¶

A passive observer can usually infer artifact boundaries, repeated structure, cadence, missingness, and candidate state transitions. The observer usually cannot prove physical truth, application intent, complete system state, or engineering-unit meaning without semantic authority and timing provenance.

Python Model¶

No current runtime example is claimed for this draft page. Keep reader claims at the artifact and source level until a separate implementation plan adds a tested model.

Local Teaching Notes¶

The artifact and diagrams are synthetic teaching material. The page intentionally omits conformance timing tables, electrical design detail, proprietary configuration, and exhaustive standard behavior.

Source Confidence¶

Source confidence is medium for scope and terminology, with semantic claims limited to public metadata, public source notes, and synthetic teaching artifacts.

Source Notes¶

References¶

Public Sources¶

• SAE International
• SAE AS6802 Time-Triggered Ethernet — canonical-standard.
• TTTech
• TTEthernet technology information — vendor explainer.