2GT-RichandClaude Opus 5
98a72e1f7a
Closes #112. Source stays `docs/*.md`, rendered by MkDocs-Material and published to GitHub Pages by Actions. Same repository on purpose: documentation drifts, and co-location is the only thing that reliably prevents it — the pull request that changes behaviour changes the description, and review sees both. A separate repo would double the ceremony and guarantee divergence. The markdown remains readable when browsing the repository, so the site renders those files rather than replacing them. **Versioned from the start**, using mike. Images are published to GHCR and this project ships betas most days, so readers are routinely running something other than the newest build; a single "latest" would confidently describe a release they do not have. Versions follow the product rather than the docs, so the site and the running image carry the same number. **Content came first, and it had to.** The docs were eleven days and sixteen releases stale — SSH keys, bulk commands, the data-cap SMS, poller health and the timezone setting appeared in exactly zero files between them. Publishing that would have given documentation missing five of the most consequential features a polished, authoritative home, and a well-presented wrong answer is worse than an obviously rough one. Four pages now cover them: - cellular.md — signal grading, carrier aggregation, the uplink anchor, observed bands, and the data-cap SMS including why it fires early and how to calibrate the margin - ssh-keys.md — leading with what installing a key costs, because RouterOS disables password SSH for that user and the database becomes load-bearing - commands.md — why waves exist, and why reading output matters when RouterOS reports failure in text rather than an exit code - scaling.md — headroom, why it is insufficient on its own, and every tunable Pull requests build the site with `--strict`, which turns warnings into errors. That is the point of running it there at all, and it earned itself immediately: the first build failed on two links to the project README, which sits outside the docs tree. They are absolute now, so they resolve both in the rendered site and when reading the markdown on GitHub. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
5.7 KiB
Cellular (LTE)
Everything here is read from the modem your device already has. Nothing needs enabling on the device for the monitoring half; the data-cap SMS at the end is the only part that writes anything.
What a modem reports depends on the modem
This is the single most important thing to know before reading the rest. RouterOS is not the source of these fields — the cellular module is, and modules disagree.
The platform was built against a Quectel EG18-EA (MikroTik ATL 18), which reports
data-class where the documentation says access-technology, iccid where WinBox shows
UICC, status: running rather than connected, and does not report
registration-status, pin-status or tracking area at all.
Every field is therefore treated as optional. A panel showing "—" for something is usually your modem not reporting it, not a fault.
Signal quality
Four measurements are collected on the fast poll and kept as a time series:
| Field | Unit | Meaning |
|---|---|---|
| RSRP | dBm | Power of the reference signal — how loud the tower is |
| RSRQ | dB | Quality of that signal |
| SINR | dB | Signal against noise — how usable it is |
| RSSI | dBm | Wideband received power |
The panel grades the link rather than only printing numbers, and SINR leads that grade. RSRP alone misleads: the reference device reports −97 dBm — nominally "fair" — on a link running 256QAM at maximum reported channel quality with two spatial streams. That is the modem at its ceiling. RSRP moderates the grade but cannot define it.
Values that cannot be real are discarded rather than plotted. A positive dBm reading appears in real logs and means the modem is reporting something other than a measurement.
Carriers and aggregation
primary-band and ca-band arrive as composite strings — B1@20Mhz earfcn: 500 phy-cellid: 190 — and are parsed into band, bandwidth, EARFCN and physical cell id.
A Cat-18 modem reports one ca-band per aggregated carrier. Because an API sentence
flattened into an object holds one value per key, repeated attributes are preserved
explicitly; without that, a device aggregating four carriers reports only the last, and
the last is often the narrowest. The panel shows every carrier and the aggregate
bandwidth.
Uplink anchor
Uplink rides the primary carrier alone. Left on automatic, a modem anchors to whichever band it hears loudest — frequently a narrow one — and aggregates wider bands for downlink only, which caps upload no matter how much downlink is stacked on top.
When the primary is narrower than a carrier being aggregated, the panel says so. This is the actual reason operators lock bands, and it is invisible in RouterOS.
Observed bands
Bands seen serving the device accumulate from polling, and are shown beside the bands your configuration permits.
This exists because scanning is not a dependable answer to "is this band available here?" — it costs service to run and returns nothing at a site with a single base station. A band the modem has actually used demonstrably works there; one never observed is a candidate for stranding a device on a mast.
Tower and band movement
Handovers, re-registrations and band changes are reconstructed by comparing consecutive polls. A session uptime that runs backwards means the modem re-registered; a changed cell id means it handed over.
This is deliberately not log-based. The modem this was built for may log nothing at all, so polling is the vantage point that always exists.
Data-cap reset SMS
Several European carriers sell "unlimited" data that is throttled past a daily allowance, and lift the throttle when the subscriber texts a short code.
Configure per interface: number, allowance, reset time and timezone, cooldown, and how far early to send.
Why it sends early
Interface byte counters do not survive a reboot, so there is no running total to read — usage is accumulated poll to poll. That makes the figure a permanent undercount: traffic during a reboot, a missed poll, or before the device was adopted is invisible.
Undercounting fires late, and late means already throttled. So the trigger fires below the configured allowance, 5% by default. Firing early costs one message; firing late costs the evening.
The saving grace is that the carrier resets daily too, so the error cannot accumulate past a single period.
Calibrating the margin
If you are throttled while the bar still reads under the trigger point, the gap is the correction. Throttled at 8.7 GB against a 10 GB allowance means roughly a 13% undercount; set "send early by" to 15–20%.
Device reboots and manager downtime both widen the gap and are visible to you but not to us.
Sending manually
The Send now button is independent of everything else — not gated on the rule being enabled, on a threshold, or on the usage estimate. It is the trustworthy half: one known action for a reason you already have. The automatic trigger is a convenience layer on top.
The automatic side carries a cooldown, because usage sits at the cap once reached rather than above it. Without one, a link parked on its limit would text the carrier on every poll.
Requirements and a trap
The modem needs SMS enabled — /tool/sms/print should report receive-enabled: yes and
the port your interface uses.
If that output also shows sms-storage: sim with remove-sent-sms-after-send: no, sent
messages accumulate on the SIM. A SIM holds twenty or thirty, and a full store makes
sending fail silently — the worst possible failure here. Setting
remove-sent-sms-after-send=yes removes the risk.
Every send is recorded with the counter reading at the time, so a misfire is explainable rather than mysterious.