H3C S12500 Installation Instructions Manual page 12

Figure 1-4 S12518 rear view
(1) Lower fan tray slot
(3) Two power entry module slots
(5) System air exhaust vents
(7) Cover plate
(9) System air intake vents
The S12518 provides two MPU slots, 18 LPU slots, and nine switching fabric module slots.
The chassis top provides two power frames to accommodate up to 2 × 6 PSUs.
The rear of the chassis has two fan trays into which fans can be inserted horizontally. The fan on
top exhausts air and the one below it draws in fresh air.
Backplane
The backplane of an S12500 switch is located in the integrated chassis. It implements high-speed data
interconnection between switching fabric modules and LPUs, and system management and control
signal exchange between MPUs and LPUs and switching fabric modules. The backplane mainly
implements these functions:
Provides communication channels for signal exchange between boards.
Supports hot-swapping of boards.
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（7）
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(2) Upper fan tray slot
(4) Power air exhaust vents
(6) Switching fabric module slots (slots 20 to 28)
(8) Air filter
(10) Grounding screw
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