The Link indicator of the Fibre Channel front-end port is steady red or off. Possible causes for a Fibre Channel link failure: The. In an optical network, alarm propagation defines how different alarms propagate in a larger link during any failure in the network. Hence, the network administrator can assess the health of the. This chapter provides a description, severity, and troubleshooting procedure for each commonly encountered Cisco NCS 1010 optical application alarm and condition. When an alarm is raised, refer to its clearing procedure. Default Severity: Minor (MN), Non-Service-Affecting (NSA) Logical Object: OTS. Log in to the DeviceManager and choose System > Hardware > Devices.