Juniper J-series Services Router J4350 Getting Started Manual page 127

The J2320 chassis height of 1.75 in. (4.45 cm) equals 1 U. The J2350 chassis height
of 2.61 in. (6.63 cm) equals 1.5 U. Each U is a standard rack unit defined in Cabinets,
Racks, Panels, and Associated Equipment (document number EIA-310-D) published
by the Electronics Industry Association.
Rack Size and Strength for J4350 and J6350 Routers
The Services Router is designed for installation in a rack that complies with either
of the following standards:
The rack rails must be spaced widely enough to accommodate the router chassis's
external dimensions: 3.44 in. (8.74 cm) high, 17.44 in. (44.3 cm) wide, and 21.13
in. (53.67 cm) deep.
The outer edges of the mounting ears extend the width of either chassis to 19.44 in.
(48.38 cm), and the front of the chassis extends approximately 0.5 in. (1.27 cm)
beyond the mounting ears. The spacing of rails and adjacent racks must also allow
for the clearances around the router and rack. (See "General Site
Guidelines" on page 103.)
CAUTION: If you are mounting the router in a cabinet, be sure that ventilation is
sufficient to prevent overheating.
If a front-mount rack is used, we recommend supporting the back of the router with
a shelf or other structure.
The J4350, and J6350 chassis height of 3.44 in. (8.74 cm) equals 2 U. Each U is a
standard rack unit defined in Cabinets, Racks, Panels, and Associated Equipment
(document number EIA-310-D) published by the Electronics Industry Association.
Connection to Building Structure
Always secure the rack to the structure of the building. If your geographical area is
subject to earthquakes, bolt the rack to the floor. For maximum stability, also secure
the rack to ceiling brackets. For more information, see "Rack-Mounting Requirements
and Warnings" on page 267.
A 19-in. rack as defined in Cabinets, Racks, Panels, and Associated Equipment
(document number EIA-310-D) published by the Electronics Industry Association
( )
http://www.eia.org
A 600-mm rack as defined in the four-part Equipment Engineering (EE); European
telecommunications standard for equipment practice (document numbers ETS 300
119-1 through 119-4) published by the European Telecommunications Standards
Institute ( http://www.etsi.org
The horizontal spacing between the rails in a rack that complies with this standard
is usually wider than the router's mounting ears, which measure 19 in. (48.2 cm)
from outer edge to outer edge. Use approved wing devices to narrow the opening
between the rails as required.
Chapter 5: Preparing for Router Installation
)
Rack Requirements
105