Chassis Card Cages; Chassis Backplane - Cisco 12416 Replacement Instructions Manual

Chassis Card Cages

The router has three integral card cages: the upper card cage, the lower card cage, and the switch fabric
card cage. (See
The upper card cage has eight user-configurable slots that support a combination of line cards and a route
processor (RP). The far left slot in the upper card cage is a dedicated slot for a pre-installed alarm card.
The far right slot (slot 7) in the upper card cage is reserved for the RP. The remainder of the slots in the
upper card cage (slots 0 through 6) can be populated with any of the line cards supported by the router.
The lower card cage also has eight user-configurable slots that support more line cards and an optional,
redundant RP. The lower card cage is an inverted, or head-down, copy of the upper card cage, meaning
that cards are installed the same way they are installed in the upper card cage, but in an inverted or
head-down orientation. The far right slot in the lower card cage is dedicated to a second alarm card,
followed by slots 8 through 15 moving right to left.
Note If the router is equipped with an optional, redundant RP, it must be installed in the far left slot of the
lower card cage (slot 8). If the router is not equipped with an optional, redundant RP, a line card can be
installed in slot 8 of the lower card cage.
The switch fabric card cage has five slots for the cards that contain the switch fabric circuitry. These
cards are the clock and scheduler cards (CSCs) and the switch fabric cards (SFCs). The card slots in the
switch fabric card cage are keyed to accept specific card types. The two far left slots (labeled CSC0 and
CSC1) accept CSCs; the three far right slots (labeled SFC1, SFC2, and SFC3) accept SFCs.
All line card slots must be filled at all times to maintain proper chassis card cage alignment; blank filler
Caution
line cards are available for this purpose as necessary. Installed line cards remain in their slots except
during replacement.

Chassis Backplane

The three card cages are tied together electrically through a passive system backplane in the back of the
chassis. Nearly all the wiring in the router is contained within or connected to the chassis backplane. The
chassis backplane distributes DC power to all the cards and blower modules in the router and provides
the physical communication pathway between cards, both for network data and system communication
across the internal system maintenance bus (MBus).
Cooling
The two removable blower modules at the top and bottom of the chassis (see
cooling air for all cards in the three card cages. In the power shelf, each power module contains a fan
that draws cooler air into the front of the power module and forces warmed air out the back of the power
shelf.
Power
The router can be ordered with the AC-input power subsystem with three AC-input power supplies, or
the DC-input power subsystem with four DC-input power entry modules (PEMs).
78-16082-01
Figure 1.)
Cisco 12016, Cisco 12416, and Cisco 12816 Router Chassis Replacement Instructions
Chassis Overview
Figure 1 on page 2) provide
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