Huawei's troubleshooting guidance foriSCSI Link Failurestates that when therunning status of an iSCSI host/front-end port is ''Link down''and thelink indicator is steady red or off, the fault is investigated as aphysical/link-layer problem. Huawei's documented possible causes include items such ascables between the host and storage being removed or damaged,optical module faults/incompatibility, orfront-end port faults.

Therefore,Acan be a possible cause because Huawei has a specific fault case for anincompatible optical module typecausing the port to be unavailable.Ccan also be a possible cause because Huawei explicitly listscables removed or damaged/looseas a cause of the link-down condition.

BandDarenotpossible causes of this specific exception. Incorrect IP settings on either thestorage iSCSI front-end portor theapplication server service network portarenetwork-layer configuration issues, but they donotcause the physical link indicator to turnsteady redor the port running status to becomeLink down. A physical link-down alarm points to hardware, cabling, or optical-module problems instead.