31 Days Before Your CCNA Exam

Day 17Connecting and Booting RoutersCCNA 640-802 Exam Topics■Select the appropriate media, cables, ports, and connectors to connect routers to other networkdevices and hosts.■Describe the operation of Cisco routers (including router bootup process, POST, routercomponents).Key TopicsToday we review basic router components, the router bootup process, router interfaces, and connectingto routers. The content for today’s review is rather light. Take this opportunity to reviewmore difficult material from previous days or move on to the next day when you’re done here. Youmight also simply take a break.Router Internal ComponentsSimilar to a PC, a router also includes the following internal components:■■CPU: Executes the operating system instructions, such as system initialization, routing functions,and network interface control.RAM: Volatile memory that stores data structures needed by the CPU while the router ispowered, including— Operating system: Cisco IOS Software is copied into RAM during bootup.— Running configuration file: Stores the configuration commands that the router’s IOS iscurrently using.— IP routing table: Stores information about directly connected and remote networks.— ARP cache: Similar to the ARP cache on a PC.— Packet buffering: Packets are temporarily stored in a buffer when received on an interfaceor before they exit an interface.■ROM: A form of permanent storage used to store— Bootstrap instructions— Basic diagnostic software— Scaled-down version of IOS