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Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter
Rack-Mounting the MGX 8220 Units
Horizontal Positioning
MGX 8220 modules are designed to be mounted to two vertical rack-mounting rails. A front-mounting
rail is used as one mounting point using the flanges provided at the front of each MGX 8220 module.
A second rail, either at the r ear o f th e r ac k or at an intermediate positio n , i s u sed f or t he s eco n d
mounting point (mounting brac kets are provided for attaching th e m o d ul e t o th e s e co nd r ai l). T he
allowable positions for in ter med i ate rails is shown in Figu re 7 -1.
Figure7-1 Mounting Rail Positions
Vertical Positioning
The MGX 8220 units are mounted in a specific order from the bottom to the top.
The AC power module (if used) is mounted first, then the fan cooling assembly is mounted, then the
first shelf is mounted, and then th e s e co nd sh el f (i f in sta lled) is mounted.
If a third and fourth shelf is installed, a b ooster cooling assemb ly must be mounted imm ediately above
the second shelf and immediat ely b el ow t he th ir d an d f our th s h elve s. T he plenum or spacer unit is
mounted last above the highest shel f. If a cable management kit is used in a two shelf or four shelf r ack,
the top unit must be a plenum because cable management hardware is not supported by the spacer unit.
When each module is installe d, th er e sh o ul d be ap pr o xi mat el y 1/ 32 o f an in ch ve rt ica l sp ac e between
adjacent modules. This can be achieved by en su ri ng th at each mo d ul e is i nst all ed at t he cen te r of each
standard rack increment. T his space is important becau se it allows cards, fan, and powe r entry modules
to be removed without interference. Hardware is available in the inst allation kits for this purpose. (See
Figure7-4.)
Racks with one and two shel ves ar e shown in Figure 7-2. Rack s wi th three and four shelves are sh ow n
in Figure7-3.
The MGX 8220 shelf and cooling assembly rely on t heir cont act wit h the rack f or groundi ng. Ther efore,
the rack should be properly connected to earth ground.
Module
Rear rail
5.0"
10.0"
19.86"
MGX 8220 Depth 21.39”
Allowable intermediate
rail positions
Front rail
H8274