NE20 connects to a PC directly. Repeat drawing and plugging the net cables between PC and NE20, and the LED for port state is normal. However, alarm information is not found in DMS.
If the interface of NE20 is not configured with IP address, it will be down physically if the net cable is drawn out at this time, which is not reported to NMS. If the port is confiugred with IP address, both physical interface and the protocol will be down if the net cable is drawn out; therefore, NE20 will report the trap-related information to DMS, generating alarms.