Cisco 7200 VXR User Manual page 16

Field-Replaceable Units
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Cisco 7200 VXR Installation and Configuration Guide
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overflow (except in the NPE-100, which contains no packet SRAM). The
standard configuration is 32 MB, with up to 128 MB available through
single in-line memory module (SIMM) upgrades.
The NPE-175 and NPE-225 use SDRAM for providing code, data, and
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packet storage.
The NPE-300 uses SDRAM for storing all packets received or sent from
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network interfaces. The SDRAM also stores routing tables and network
accounting applications. Two independent SDRAM memory arrays in the
system allow concurrent access by port adapters and the processor.
– The NPE-400 uses SDRAM for storing all packets received or sent from
network interfaces. The SDRAM memory array in the system allows
concurrent access by port adapters and the processor.
– The NSE-1 uses SDRAM for providing code, data, and packet storage.
Packet SRAM for storing packets of information in preparation for fast
switching
– The NPE-100 does not have packet SRAM.
The NPE-150 has 1 MB of SRAM.
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The NPE-175 does not have packet SRAM.
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The NPE-200 has 4 MB of SRAM.
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The NPE-225 does not have packet SRAM.
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– The NPE-300 does not have packet SRAM.
The NPE-400 does not have packet SRAM.
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– The NSE-1 does not have packet SRAM.
Cache memory
The NPE-100, NPE-150, and NPE-200 have unified cache SRAM that
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functions as the secondary cache for the microprocessor. (The primary
cache is within the microprocessor.)
The NPE-175 and NPE-225 have two levels of cache: a primary cache
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that is internal to the processor and a secondary, 2-MB external cache
that provides additional high-speed storage for data and instructions.
Chapter 1 Cisco 7200 VXR Product Overview
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