Symptom

Catalyst 9300-48S may see delayed optic recognition with GLC-SX-MMD after bootup. It may take up to 10 minutes for the optic to be recognized after booting, but in some scenarios it is never recognized at all. This issue is specific to any Catalyst 9300, that uses 1G SFP ports as they all use a common PHY where this fix would have an impact, for example C9300-24S. It is also not specific to the GLC-SX-MMD SFP module, and can be observed with any SFP. Optics will not appear in show inventory and show interfaces status will show the optic type as 'unknown' This log takes approximately 10 minutes after bootup to appear *Feb 8 20:14:36.680: %PLATFORM_PM-6-MODULE_INSERTED: SFP module inserted with interface name Gi1/0/2 In some scenarios the optic may never be recognized at all.

Conditions

Hardware: C9300-48S This has been seen with GLC-SX-MMD. This behavior has been first observed on 17.9.4, 17.9.4a, and 17.12.1, other releases may be impacted as well.

Workaround

If optics fail to be recognized, a reload may allow the optics to be detected on the next bootup. Downgrading to 17.6.5 will resolve this issue.

Further Problem Description