Juniper Networks M160 manual Field-Replaceable Units FRUs, System Redundancy

M160 Internet Router Hardware Guide

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 down 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 4 lists the FRUs for the M160 router.

Table 4: Field-Replaceable Units

Hot-Removable and		FRUs That Require Powering
Hot-Insertable FRUs	Hot-Pluggable FRUs	Down the Router
Air filter	Miscellaneous Control	Circuit breaker box
Fan tray (located behind	Subsystem (MCS)	Connector Interface Panel (CIP)
the cable management	Packet Forwarding Engine
system)	Clock Generator (PCG)
Flexible PIC Concentrator	Routing Engine
(FPC)	Switching and Forwarding
Physical Interface Card	Module (SFM)
(PIC)
Power supply
Small form factor
pluggable (SFP)

For FRU replacement instructions, see “Replacing Hardware

Components” on page 139.

System Redundancy

The router is designed so that no single point of failure can cause the entire system to fail. The following hardware components contribute to system redundancy:

Cooling system—When the temperature inside the router is below the acceptable maximum, the cooling system’s components function at less than full speed. If the temperature becomes excessive—for example, because a cooling system component is removed—the MCS automatically increases the speed of the remaining components to reduce the temperature. The cooling

4 System Redundancy