M120 Field-Replaceable Units (FRUs)
Field-replaceable units (FRUs) are router components that can be replaced at the customer site. Replacing most FRUs requires minimal router downtime. The router uses the following types of FRUs:
- Hot-removable and hot-insertable FRUs—You can remove and replace these components without powering off the router or disrupting the routing functions.
- Hot-pluggable FRUs—You can remove and replace these components without powering down the router, but the routing functions of the system are interrupted when the component is removed.
Table 1 lists the FRUs for the M120 router. If the router contains a redundant host subsystem, the Control Board (CB) and the Routing Engine are hot-removable and hot-insertable. Before you replace a CB or a Routing Engine, you must take the host subsystem offline (see Taking the M120 Host Subsystem Offline).
Table 1: M120 Field-Replaceable Units





