Cisco Systems XR 12410 manual PRP Sdram

Chapter 4 Troubleshooting the Installation

Troubleshooting the Processor Subsystem

PRP SDRAM

The PRP uses Error Checking and Correction (ECC) Synchronized Dynamic Random Access Memory (SDRAM) to store routing tables, protocols, network accounting applications, and to run Cisco IOS XR software.

Table 4-3lists the DRAM configurations for the PRP. If you are using:

•One DIMM—Bank 1 (U15) must be populated first.

•Two DIMMs—You cannot mix memory sizes; both banks must contain the same size DIMM.

Table 4-3 PRP DRAM Configurations

Total
SDRAM	SDRAM Sockets	Number of DIMMs
512 MB1	U15 (bank 1)	One 512 MB DIMM
	U18 (bank 2)	or
		Two 256 MB DIMMs
1 GB	U15 (bank 1)	One 1 GB DIMM
	U18 (bank 2)	or
		Two 512 MB DIMMs
2 GB	U15 (bank 1)	Two 1 GB DIMMs
	U18 (bank 2)
1. Default shipping configuration.

Caution DRAM DIMMs must be 3.3-volt, 60-nanosecond devices only. Do not attempt to install other devices in the DIMM sockets. To prevent memory problems, use the Cisco approved memory products listed in Table 4-3.

PRP SRAM

Static Random Access Memory (SRAM) provides 2 MB of secondary CPU cache memory. Its principal function is to act as a staging area for routing table updates, and for information sent to and received from the line cards. SRAM is not user-configurable and cannot be upgraded in the field.

	Cisco XR 12410 Router Installation Guide
4-22	OL-13832-01