Deterministic Simulation and Replay

The sim command family runs an EVSE and an EVCC as twins inside one process, without sockets, and produces a symbolic transcript of the message sequence with a SHA-256 hash. The same scenario with the same seed always yields the same transcript, so a simulation report can be replayed and verified months later, on another machine, or in CI. Use it for regression checks, for reproducing a reported sequence without hardware and for attaching a compact reproducer to a support case.

Deterministic simulations are symbolic: they record message families and state transitions, not wire bytes. They prove that ChargeLink's own sequencing is stable; they do not prove interoperability with a physical peer.

$CL   = 'C:\ChargeLink\0.5.0-rc2\pc1\bin\chargelink.exe'
$Data = 'C:\ChargeLinkData'
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim policy

Catalogs

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim iso20-catalog
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim legacy-catalog
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim tls-catalog
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim iso20-negative-corpus
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim legacy-negative-corpus
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim tls-negative-corpus

ISO 15118-20 scenarios (10)

Scenario	Category	Expected verdict	Message families
`common-eim-nominal`	common	pass	sdp, app-protocol, session, authorization, service-discovery
`common-pnc-tls`	common-security	pass	tls, app-protocol, authorization, service-selection
`dc-bpt-nominal`	dc	pass	sdp, session, schedule, dc-precharge, dc-loop, stop
`dc-stop-energy-transfer`	dc	pass	session, power-delivery, stop
`dc-service-renegotiation`	dc	pass	service-discovery, service-selection, schedule, dc-loop
`dc-session-resume`	recovery	pass	session, resume, authorization, dc-loop
`dc-timeout-recovery`	fault	expected fault path	timeout, retry, safe-stop
`dc-negative-response-code`	fault	expected fault path	response-code, service-selection, safe-stop
`dc-power-limit-fault`	fault	expected fault path	precharge, power-limit, safe-stop
`dc-evcc-abort`	fault	expected fault path	abort, safe-stop

ISO 15118-2 and DIN 70121 scenarios (12)

iso2-dc-pnc-nominal, iso2-dc-eim-nominal, iso2-ac-eim-nominal, iso2-cert-install, iso2-cert-update, iso2-current-demand-loop, iso2-timeout-recovery, iso2-negative-payment, din-dc-basic, din-current-demand-loop, din-timeout-recovery, din-evcc-abort.

TLS/PKI/PnC campaigns (12)

iso20-pnc-contract-valid, iso20-pnc-expired-contract, iso20-pnc-untrusted-root, iso20-pnc-wrong-eku, iso20-pnc-revoked-contract, iso20-pnc-malformed-cert, iso20-pnc-ocsp-soft-fail, iso20-pnc-redaction-boundary, iso2-pnc-contract-install, iso2-pnc-contract-update, tls-hostname-mismatch, tls-private-key-export-block. All use redacted hash fixture material only.

Run one scenario

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim paired --protocol iso15118-20 --scenario dc-bpt-nominal --seed 42 --run-id sim-dc-bpt-42 --write-artifacts --output "$Data\tests\sim-dc-bpt-42.json"
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim iso20-scenario --scenario dc-timeout-recovery --seed 7 --run-id sim-timeout-7 --write-artifacts
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim legacy-scenario --protocol din70121 --scenario din-dc-basic --seed 1 --run-id sim-din-1 --write-artifacts
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim tls-campaign --campaign iso20-pnc-expired-contract --seed 1 --run-id sim-tls-expired --write-artifacts

Artifacts (under the run directory): sim\paired-simulation-report.json and sim\paired-simulation-transcript.json for paired; sim\iso15118-20-scenario-report.json / -transcript.json; sim\legacy-hlc-scenario-report.json / -transcript.json; pki\tls-pki-pnc-campaign-report.json / -transcript.json. The report contains the seed, the event count and the transcript SHA-256.

Run a suite

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim iso20-suite  --profile dc-bpt-expanded     --seed 1 --run-id suite-iso20 --write-artifacts
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim legacy-suite --profile legacy-expanded     --seed 1 --run-id suite-legacy --write-artifacts
chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim tls-suite    --profile tls-pki-pnc-expanded --seed 1 --run-id suite-tls --write-artifacts

A suite runs every scenario or campaign of its catalog with the given seed and records one transcript hash per scenario. Keep the suite output of a release as the baseline; a changed hash for the same seed after an upgrade is a behavioural change that must be explained.

Replay and verify

chargelink --runtime-root "$Data\runtime" --artifact-root "$Data\artifacts" --json sim replay --trace "$Data\tests\sim-dc-bpt-42.json" --output "$Data\tests\sim-dc-bpt-42.replay.json"

Expected: status: replay_verified, expected_transcript_sha256 equal to actual_transcript_sha256, mismatch: null. A mismatch names the first divergent event. Replay accepts the simulation report written by --output, not a live protocol trace.

Practical uses

Reproduce a software regression without reconnecting laboratory hardware.
Compare behaviour before and after a ChargeLink update (same seed, compare hashes).
Verify a known negative case in CI (expected_verdict: expected_fault_path).
Attach a deterministic reproducer to a support ticket (the report file is self-contained).
Review a test sequence when the original bench is unavailable.

Related engineering lanes

The EXI corpus (exi roundtrip, exi completeness, exi negative-corpus) exercises the native codec against golden bytes.