How each NOS validates a module

Between "module detected" and "port up" every network OS runs a check on the module's identity. What it compares, what it does when the comparison fails and whether an administrator can override it differ by vendor, platform and release — and that difference is the whole subject of transceiver compatibility. This page lays the behaviours side by side, as documented by the vendors and observed in the field, so a module read on the bench can be judged against the box it is meant for.

What can be checked

Behaviour by vendor

Public commands and behaviours as of recent releases; details vary by platform and version.

Where a vendor's override exists, it is generally offered as is: the module works, but the vendor does not commit to supporting the combination. Fleet decisions belong with the network owner (Third-party optics).

What "coded for vendor X" has to satisfy

How the bench side works: Vendor lock & coding, EEPROM recoding.

Reading the rejection

Per-NOS commands to see these states: Verifying optics on a switch.

Changes with software upgrades

Vendors tighten or loosen checks between releases: new signature validation, new supported-optics lists, removed hidden commands, changed DDM handling. A fleet of third-party or coded optics that worked yesterday can be errdisabled after an upgrade (Compatibility matrices & firmware).

In CodingBox

CodingBox shows the exact bytes each check above reads — vendor name, PN, checksums, compliance codes, power class — and the code database holds identities that a given platform class accepts. Verify on a test port after coding; the switch, not the bench, has the last word (Check transceiver).

The server-side counterpart — driver whitelists per NIC vendor, Intel overrides, Windows and ESXi behaviour: Transceiver compatibility on NICs.