Real incidents caused by third-party optics: slow I2C crashing a linecard and a DDM uptime overflow bug
1
In a NANOG discussion about vendor lock-in, an operator described two concrete failures. First, a third-party optic answered I2C reads too slowly; the switch vendor's polling code did not handle the timeout and crashed the linecard control plane, and the vendor refused to treat it as a bug because it did not happen with their optics. Second, a third-party SFP had a firmware defect where after 2^31 hundredths of a second the uptime counter overwrote the DDM temperature field, causing link flaps on many devices at once and risking simultaneous outages after mass reboots.
- Hardware: carrier routers/switches (unnamed vendor)
- Transceivers: third-party SFP with DDM
- Form factor: SFP
Symptoms / messages:
linecard control-plane crash on I2C timeout
DDM temperature field corrupted by uptime overflow
fleet-wide link flapping
Comments 2
Buy third-party optics from professional suppliers who track serial numbers and component origins so that recalls are possible; cheap broker-sourced optics are untraceable.
Major vendors state in RFP answers that they will not deny contractual support for third-party optics, but may require replacing a suspect optic with a first-party one before continuing TAC work.