Cisco Systems Cisco 12008 manual Overview of the Cisco

Overview of the Cisco 12008

•Up to 2 GB of SDRAM on two PC133-compliant, dual in-line memory modules (DIMMs). 512 MB of SDRAM is the default shipping configuration. SDRAM is field replaceable.

•Two MB of SRAM for secondary CPU cache memory functions. SRAM is not user configurable or field replaceable.

•Two MB of NVRAM. NVRAM is not user configurable or field replaceable.

•Additional memory components used by the system, including onboard Flash memory and up to two Flash memory cards.

•Air-temperature sensors for environmental monitoring.

The Cisco IOS software images that run the Cisco 12000 series Internet Router system are stored in Flash memory. Two types of Flash memory ship with the PRP:

1Onboard Flash memory — Ships as a single in-line memory module (SIMM). This Flash memory contains the Cisco IOS boot image (bootflash) and is not field replaceable.

2Flash disk— The PRP ships with a Flash disk that can be installed in either Flash disk slot. (See Figure 1-12.) The Flash disk contains the Cisco IOS software image.

Storing the Cisco IOS images in Flash memory enables you to download and boot from upgraded Cisco IOS software images remotely, or from software images that reside in PRP Flash memory.

Cisco 12000 series Internet Routers support downloadable system software for most Cisco IOS software upgrades. This enables you to remotely download, store, and boot from a new Cisco IOS software image. The Cisco IOS software runs from within the PRPs SDRAM.

Figure 1-12 shows the locations of the various hardware components on the PRP.

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