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Cisco Employee

Cisco IOS System Software vs. IOS and CATOS

What are the pros and cons between captioned OS options on SUP1A/MSFC2? We've always used CATOS and Router IOS.


Re: Cisco IOS System Software vs. IOS and CATOS

Hi Friend,

Cisco is slowly moving towards Native IOS now as it is much easy to manage the big box with single interface instead of hoping between supervisor and msfc in hybrid mode (CATOS MODE).

There is a single console connection, configuration file, and software image so the complexity is less as it is there to manage different config file, images and consoles in CATOS mode.

Also have a look at this link for some differences between the hybrid mode and native mode

HTH, if yes please rate the post.


Cisco Employee

Re: Cisco IOS System Software vs. IOS and CATOS

Thank you Ankur,

Where is the IOS System Software (Native) stored, on the SUP or MSFC or both? I've look at Cisco's instructions, but I am not 100% clear on that point.



Re: Cisco IOS System Software vs. IOS and CATOS

Hi Friend,

The IOS is stored on the supervisor engine's bootflash and has both the SP and the RP files in a single IOS. First SP boots up with its IOS file filename_sp and after 30 seconds it changes the ownership to MSFC (RP) to bootup. Once MSFC starts booting up you will see an image naming file_rp, that denotes your rp is booting up with its image file.

HTH, Please rate if it does.

-amit singh