q-ecn-congestion
· RFC 9000 §13.4 · correctness · layer quic · udp/4508 · MUST
Passing this means: Rejected something invalid, with the code the RFC names.
Anomaly type: transport
How each client answered
| Client | Version | Verdict | What happened |
|---|---|---|---|
| curl | ngtcp2/1.11.0 | Inconclusive | The run did not exercise this test: no ECN counts came back at all. §13.4.1 requires reporting only where the ECN field is accessible, and a path that stripped the codepoint cannot be told apart from a client that does not report. |
| quinn | noq fork | Inconclusive | The run did not exercise this test: no ECN counts came back at all. §13.4.1 requires reporting only where the ECN field is accessible, and a path that stripped the codepoint cannot be told apart from a client that does not report. |
| aioquic | 1.3.0 | Inconclusive | The run did not exercise this test: no ECN counts came back at all. §13.4.1 requires reporting only where the ECN field is accessible, and a path that stripped the codepoint cannot be told apart from a client that does not report. |
| chromium | build 1223 | Pass | Responded correctly: reported the congestion back: 12 ECN-CE among 0 ECT(0) and 0 ECT(1), after 17 datagram(s) were marked. |
| quic-go | quic-go v0.61.0 | Pass | Responded correctly: reported the congestion back: 6 ECN-CE among 0 ECT(0) and 0 ECT(1), after 29 datagram(s) were marked. |
| quiche | 0.30.0 | Inconclusive | The run did not exercise this test: no ECN counts came back at all. §13.4.1 requires reporting only where the ECN field is accessible, and a path that stripped the codepoint cannot be told apart from a client that does not report. |
| neqo | 0.31.1 | Inconclusive | The run did not exercise this test: no ECN counts came back at all. §13.4.1 requires reporting only where the ECN field is accessible, and a path that stripped the codepoint cannot be told apart from a client that does not report. |
What the clause requires
Report the CE count back in the ECN section of an ACK. §13.4.1 makes this the same conditional requirement as reporting ECT(0) — an endpoint MUST provide feedback about the markings it receives "if these are accessible" — and CE is the marking that matters, since it is how a path says it is congested. Distinct from the ECT(0) test on the neighbouring port: that one asks whether a client reports markings at all, and this asks whether it distinguishes the one that means something. A client that echoes ECT(0) counts faithfully and never reports a CE has a congestion signal it cannot see. Silence is inconclusive, not a failure, for the same reason: the ECN field may be inaccessible to the peer, and a path that rewrites the codepoint in transit is indistinguishable from here.
Judged against RFC 9000.
Run this one yourself
Every test is reachable from your own client. Nothing here needs an account.
curl -s https://conformance.pqcrypta.com/catalog.json \
| jq '.tests[] | select(.id == "q-ecn-congestion")'What this suite is · The full grid · All clients · All tests · Findings