Chap 5 Startup and Setup Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology

Overview Start a router for the first time by using the correct commands Startup sequence to do an initial configuration of a router

Router Boot Sequence and Setup Mode Router startup routine Router startup sequence Commands related to router startup

Router startup routine A router initializes by Hardware test Load the bootstrap Load the OS Load a configuration file

Cisco router powers up POST: Power-on self test Executes diagnostics from ROM Verify the basic operation of the CPU, memory, and network interface ports

Router startup sequence: Step 1 The generic bootstrap loader, in ROM, executes on the CPU card Preset operation to load instructions that in turn cause other instructions to be loaded into memory, or cause entry into other configuration modes

Router startup sequence: Step 2 The IOS location is disclosed in the boot field of the conf. register If the boot field indicates a Flash, or network load, boot system commands in the conf. file indicate the exact location of the image

OSI is loaded When it is loaded and operational, the OS locates the hardware and software components and lists the results on the console terminal Router startup sequence: Step 3

The conf. file (NVRAM) is loaded into main memory and executed one line at a time These conf. commands start routing processes, supply addresses for interfaces, set media characteristics, and so on Router startup sequence: Step 4

If no valid conf. file exists in NVRAM, the OSI executes a question-driven initial configuration routine Minimal configuration Router startup sequence: Step 5

The Startup Order Bootstrap from ROM IOS from flash IOS from tftp IOS from ROM Config from NVRAM Config from tftp Config from setup

Commands related to router startup show startup-config Display the backup conf. files show running-config Display active conf. files erase startup-config Deletes the backup conf. file in NVRAM

Commands related to router startup reload (reboot) Cause it to run through the entire startup process setup: enter setup mode from the privileged EXEC prompt

System Configuration Dialog Using the setup command Setting up global parameters Setting up interface parameters Setting up script review and use

Using the setup command The main purpose of the setup mode is to bring up, quickly, a minimal configuration for any router that cannot find its configuration

Using the setup command Default answers appear in square brackets [ ] During the setup process, you can press Control+C at any time to terminate the process and start over

Setting up global parameters The router host name An enable password The "enable password" is used when no "enable secret word" exists

Setting up global parameters Enable secret word A one-way cryptographic secret word that is used instead of the "enable password" when it exists

Setting up script review and use When you complete the conf. process Display the configurations Ask if you want to use this conf. Yes: the conf. will be executed and saved to NVRAM

Summary The router initializes by loading a bootstrap, the OS, and a configuration file If no configuration file exists, the router enters setup mode