What is the difference between the startup sequence of cisco switches and routers?

 

Startup Process of cisco routers and switches:

 

I. cisco switch startup process:

The START loader is a small program stored in NVRAM and executed when the switch is started for the first time.

① The vswitch loads the loader software from NVRAM.

② Start the loader.

③ Perform POST (self-check on startup) for the low-level CPU subsystem ).

④ Initialize the Flash file system on the system motherboard.

⑤ Load the default OS software image to the memory and start the switch.

⑥ The operating system runs with the config. text file, which is stored in the flash memory of the switch.

 

Note: The loader can also be used to access a vswitch when the operating system is unavailable. The START loader has a command line tool that can be used to access files stored in flash memory before the operating system. From the start loader command line, you can enter a command to format the Flash file system, reinstall the operating system software image, or restore the file when the password is lost or forgotten.

 

Ii. cisco router startup process:

① After power-on, the router executes POST (BOOT self-check). POST is the microcode stored in the ROM to check whether the hardware of the device can run normally.

2 bootstrap find and load IOS, bootstrap is stored in the ROM in the micro code, IOS stored in flash, the default Loading Order: flash -- TFTP--ROM (mini IOS ).

③ IOS searches for startup-config in NVRAM, copies it to RAM, and CALLS running-config to run the vro. If NVRAM does not have startup-config, send the broadcast to all interfaces to search for the TFTP host configuration file. If not, start setup mode for configuration.

 

From flour0722's BLOG