Juniper M120 Hardware Manual page 68

M120 Multiservice Edge Router Hardware Guide
Table 16: M120 Rack Requirements and Specifications (continued)
Rack Requirement
Rack size and strength
Rack connection to the building
structure
40
Guidelines
Ensure that the rack is a 19-in. rack as defined in Cabinets, Racks, Panels, and
Associated Equipment (document number EIA-310–D) published by the Electronics
http://www.eia.org
Industry Association (
Ensure that the rack is one of the following standard lengths:
23.62 in. (600 mm)
30.0 in. (762 mm)
21.5 in. (800 mm)
The rack rails must be spaced widely enough to accommodate the router chassis's
external dimensions: 20.75 in. (52.71 cm) high, 24.3 in. (61.7 cm) deep, and
17.43 in. (44.3 cm) wide. The outer edges of the mounting brackets extend the width
to 19 in. (48.3 cm). The spacing of rails and adjacent racks must also allow for the
clearances around the router and rack that are specified in "M120 Clearance
Requirements for Airflow and Hardware Maintenance" on page 41.
All mounting options require you to install the supplied large mounting shelf. The
supplied small mounting shelf is needed for a front-mount four-post rack or cabinet.
If a front-mount rack is used, you must support the back of the router with the large
mounting shelf included with your shipment, or some other structure.
For a front-mount rack, you use the front-mounting flanges on the front of the
chassis instead of the mounting brackets. The flanges have holes for rack-mounting
screws, spaced at 3.5 in. (8.89 cm). In addition, if you are mounting the router in a
four-post rack or cabinet, you must install the spacer bars on the rack before you
mount the chassis. For instructions about installing the mounting hardware, see
"Installing the Mounting Hardware for a Front-Mount Four-Post Rack or Cabinet"
on page 49, "Installing the Mounting Hardware for a Front-Mount Open-Frame Rack"
on page 51, or "Installing the Mounting Hardware for a Center-Mount Open-Frame
Rack" on page 53.
The chassis height of 20.75 in. (52.71 cm) is approximately 12 U. A
rack unit defined in Cabinets, Racks, Panels, and Associated Equipment (document
number EIA-310-D) published by the Electronics Industry Association. You can stack
four M120 routers in a rack that has at least 48 U (84 in. or 2.1 m) of usable vertical
space.
The rack must be strong enough to support the weight of the fully configured router,
up to 225 lb (102.1 kg). If you stack four fully configured routers in one rack, it must
be capable of supporting about 900 lb (408.4 kg).
Ensure that the spacing of rails and adjacent racks allows for the proper clearance
around the switch and rack as specified in "M120 Clearance Requirements for Airflow
and Hardware Maintenance" on page 41.
Secure the rack to the building structure.
If earthquakes are a possibility in your geographical area, secure the rack to the
floor.
Secure the rack to the ceiling brackets as well as wall or floor brackets for maximum
stability.
).
is the standard
U
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