Mx2010 Field-Replaceable Units - Juniper MX2010 Hardware Manual

delta and three-phase wye. Individual phases are taken from three-phase feeds to individual PSMs. One
AC feed provides power to six PSMs, while the second input feed provides power to the remaining three
PSMs (supporting a total of nine PSMs).
Power supply modules (PSMs)—All nine AC or DC PSMs in a system share the load. If one PSM fails in
a redundant configuration, the remaining eight PSMs provide power to FRUs. In the AC or DC
configuration, up to nine PSMs might be required to supply power to a fully configured router. Nine
PSMs supply power to the two CB-REs (active and redundant), eight SFBs, ten MPCs, and four fan trays
(active and redundant).
Cooling system—The cooling system has a total of four fan trays— two per cooling zone (cooling zone
0 and cooling zone 1)—which are controlled and monitored by the host subsystem. Each cooling zone
consists of two fan trays. The bottom fan trays are used to cool the bottom half of the CB-REs and SFBs,
along with the ten line cards. The top fan trays are used to cool the top half of the CB-REs and SFBs. If
a fan fails or the temperature rises above the temperature threshold, the speed of the remaining fans in
the zone is automatically adjusted to keep the temperature within the acceptable range (see
Cooling System Description" on page
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MX2010 Field-Replaceable Units

Field-replaceable units (FRUs) are router components that can be replaced at the customer site (see
Table 7 on page 18). 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 off the router,
but the routing functions of the system are interrupted when the component is removed.
45).
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