200-150 · Question #94
Which process does a Cisco router perform immediately upon powering up?
The correct answer is A. POST. When a Cisco router powers on, the very first process it performs is the Power-On Self Test (POST) to verify that hardware components are functional before loading any software.
Question
Which process does a Cisco router perform immediately upon powering up?
Options
- APOST
- BBIOS
- Cbooting from NVRAM
- Dbooting from ROM
How the community answered
(38 responses)- A92% (35)
- C5% (2)
- D3% (1)
Why each option
When a Cisco router powers on, the very first process it performs is the Power-On Self Test (POST) to verify that hardware components are functional before loading any software.
POST (Power-On Self Test) is executed by firmware stored in ROM immediately at power-up to test CPU, memory, and interface hardware - only after POST passes does the router proceed to load the bootstrap and then the IOS image.
BIOS is a concept from x86 PC architecture and is not a component or process in the Cisco router boot sequence - Cisco routers use ROM-based firmware instead.
NVRAM stores the startup configuration file, which is loaded much later in the boot sequence after POST, bootstrap, and IOS image loading have all completed.
Booting from ROM refers to loading the bootstrap program or a minimal IOS image, which occurs after POST has already successfully verified the hardware.
Concept tested: Cisco router power-on boot sequence and POST
Source: https://www.cisco.com/c/en/us/support/docs/routers/3600-series-multiservice-platforms/15273-15.html
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