1G optics in MikroTik SFP+ ports: forced 1G fails to an RBFTC11 while auto-negotiation causes FCS errors to a CRS328
Contradicting MikroTik's documented advice to force 1G full duplex when using 1G optics in SFP+ ports, a Netpower Lite 7R linked to an RBFTC11 only with auto-negotiation (forced 1G gave link up but zero received packets), while the same Netpower to a CRS328-4C-20S-4S+ had heavy packet loss and FCS errors with auto-negotiation and worked better forced.
- Hardware: MikroTik Netpower Lite 7R, MikroTik RBFTC11, MikroTik CRS328-4C-20S-4S+
- Transceivers: 1G optical SFP
- Form factor: SFP, SFP+
Symptoms / messages:
link up but no packets received
FCS errors and packet loss with autoneg
Comments 1
Auto-negotiation combines port capabilities, configured speeds and the module ROM data, so it may pull settings that forced mode ignores; SFP handling also varies between RouterOS versions and sometimes regresses. No definitive rule was given.