Booting Process of Cisco Router

 BootStrap program

                     

• When Power on the Router then  First it will do POST (Power on Self Test ) . The POST analyze Hardware Component of Router . It verify that all Router interface properly working or not . After the POST it will boot itself with help of Program which is store in ROM.
• After POST it search the Location of  IOS in  flash memory ( Internetwork OS). Bootstrap program responsible for finding IOS Program. 
• After IOS found it will loaded in to RAM.
• After loading IOS it will go to NVRAM for Valid Configuration , If Configuration is available in NVRAM , then it will go to CLI mode.