M320 Chassis Description - Juniper M320 Hardware Manual

M320 Router Hardware Guide
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M320 Chassis Description

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For information about the effect of taking the host subsystem offline, see "Taking the
M320 Host Subsystem Offline" on page 160. For more information about high availability
features, see the Junos OS High Availability Configuration Guide.
Power supplies—A router with a minimum of three AC power supplies or four DC power
supplies is fully power redundant. In the AC configuration, all power supplies share the
load evenly. In the DC configuration, two power supplies share the load to some of the
components, and two other power supplies share the load to the remaining
components. In both configurations, if one power supply fails, the remaining power
supplies can provide full power to the router.
Cooling system—The cooling system has redundant components, which are controlled
by the host subsystem. If one of the fans fails, the host subsystem increases the speed
of the remaining fans to provide sufficient cooling for the router indefinitely.
M320 SIB Description on page 16
M320 Host Subsystem Description on page 18
M320 Cooling System Description on page 37
M320 Power System Description on page 33
The router chassis is a rigid sheet metal structure that houses all the other router
components (see Figure 1 on page 7). The chassis measures 34.80 in. (88.4 cm) high,
17.43 in. (44.3 cm) wide, and 25.64 in. (65.1 cm) deep (from the front-mounting flanges
to the rear of the chassis). The chassis can be installed in many types of racks or cabinets.
For more information, see Requirements Reference Example: M320 Cabinet Size and
Clearance Requirements and "Rack Requirements for the M320 Router" on page 42
The chassis includes the following features (see Figure 1 on page 7, Figure 2 on page 8,
and Figure 3 on page 9):
One pair of metal adjustable center-mounting brackets that can be attached to one
of 11 positions on the side of the chassis. You can use the brackets for mounting the
chassis in the rack or cabinet.
Two installation handles on the top to facilitate positioning the router in the rack. Do
not use the handles to lift the router.
Two electrostatic discharge points (banana plug receptacles): one front and one rear.
CAUTION: Before removing or installing components of a router, attach
an ESD strap to an ESD point and place the other end of the strap around
your bare wrist. Failure to use an ESD strap could result in damage to the
router.
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