When a Healthy ONU Drops 32,000 Frames to 1
A firmware update broke my fiber WAN. The device that broke it reported itself perfectly healthy on every check I could think of. Here is how I found the fault, the seven wrong turns I took first, and how far the evidence actually goes. The setup The uplink is an HSGQ/ODI M110 GPON SFP stick , a Realtek RTL9602C SoC inside a transceiver. Firmware V1.0-220923 works. Firmware V1.1.8-240408 reproducibly kills WAN. Same fiber, same OLT, same hardware. Only the firmware string differs. The HSGQ/ODI M110 GPON SFP stick. The cruel part is that the broken firmware looks fine. The ONU reaches O5, the GPON operational state (G.984.3): registered with the OLT, ranged, all alarm flags clear, GEM port mappings present. Every surface check is green. No service traffic reaches the host. One symptom sent me the wrong way early. Link-local control frames, LLDP (multicast) and MNDP (broadcast), still showed up in the router's traffic sniffer while service unicast did not. I read that as a host-...