Cisco Gigabit Switch Router 12008 Installation And Configuration Manual page 27

The power supplies of both types are hot-swappable, load-sharing units. In a system
equipped with two AC-input power supplies or two DC-input power supplies, if one
of the units fails or if the power source for one of the units fails, the surviving power
supply continues to operate to sustain normal router operations.
The Cisco 12008 does not support a mixture of AC-input and DC-input power
Note
supplies.
— Cisco 12000 series line cards—Any line card supported by the Cisco 12008 router
can be inserted into or removed from the router with no disruption to system
operations.
However, the functions performed by the removed card are lost to the system
temporarily until the card is either reinstalled or replaced by a like (and identically
configured) line card.
— Route Processor (RP)—As a required router component, an RP can be removed and
replaced, but you must power down the router before doing so.
An RP must be installed and operational at all times for normal system operations
to be sustained.
— Clock and scheduler card (CSC)—Also a required component, a CSC can be
removed and replaced, without disrupting normal system operations, only if a
second (redundant) CSC is installed in the system.
One CSC must be present and operational at all times to maintain normal system
operations.
— Switch fabric card (SFC)—An optional set of three SFCs can be installed in the
router at any time to provide additional switch fabric to the router. These cards
increase the data handling capacity of the router.
Any one or all of the SFCs can be removed and replaced at any time without system
operations being disrupted or the router being powered down.
For the length of time that any SFC is not functional, its switch fabric is lost to the
router as a potential data path for the router's data handling and switching functions.
Features of the Cisco 12008 Router
Product Overview 1-5