Selecting and commissioning a switch with optics in mind

Optics are where a switch project meets reality: the box is chosen for ports, features and price, and then a module that "should work" does not, the uplink cage cannot power the 40 km optic, the airflow is backwards for the rack, or the first software upgrade errdisables half the links. This page is two checklists — what to check about optics when selecting a switch, and how to commission it from unboxing to a DDM baseline — plus an acceptance test that catches marginal links before users do.

Selection criteria

Optics bill of materials

Commissioning checklist

1. Unbox and inspect — serial numbers, PSUs, fan trays, airflow SKU, uplink modules; photograph the faceplate.
2. Inventory the optics — read every module on the bench (vendor, PN, SN, date, compliance, power class, firmware) and record it against its planned port (Check transceiver, Code database).
3. Console in — set the management IP on the OOB port and VRF, credentials, NTP, syslog, SNMP/telemetry targets (Management & monitoring).
4. Software — upgrade to the target release before configuring ports; read the release notes for transceiver items (Compatibility matrices & firmware).
5. Policy lines — service unsupported-transceiver / allow-unsupported-transceiver / transceiver phony-alarm-disable if the fleet needs them; errdisable recovery.
6. Port configuration — speeds, FEC, auto-negotiation (on for DAC, off for optics), breakout maps, descriptions, LAG/MLAG membership (Port configuration recipes).
7. Insert modules — clean every connector, insert with the bail open, listen for the latch; DAC/AOC pull tabs upward on dual-row cages as the guide says.
8. Verify each port — module recognised, correct type string, link up at intended speed, FEC counters zero (Verifying optics on a switch).
9. Baseline DDM — record Rx/Tx power, bias, temperature per port ("link passport"); compare Rx to the budget (Monitoring, Rx power & budget).
10. Acceptance test — see below.
11. Document — port map, optics inventory with serials, cable IDs, photos, config backup; label both cable ends.
12. Spares on site — stored in ESD bags, dust caps on.

Acceptance test

Common commissioning mistakes

In CodingBox

Step 2 of the commissioning list is the bench: reading every module before it is racked produces the inventory, catches wrong PMDs and mislabelled parts, and — where the platform demands it — is the moment to code identities so that step 8 passes on the first try (Check transceiver, EEPROM editor).