CCIE Security Exam Quick Reference Sheets

Chapter 7. Cisco Security General

Cisco Hardware Overview

• Components of a Cisco router include RAM, NVRAM, CPU, flash, ROM, configuration registers, interfaces, ASICs, and so on.
• The RAM is used to store current configuration files and other important information such as Cisco Express Forwarding (CEF) tables. In addition, IP routing tables and buffer information are stored in the RAM. The routing protocol processes run in RAM (Border Gateway Protocol [BGP], Open Shortest Path First [OSPF] protocol, and so forth). Information in the RAM is lost if the router is power-cycled or restarted. Current configuration of a router can be viewed using the command show running-config or write terminal.
• Cisco IOS Software loaded on routers is hardware-specific ...