why IOS XE is based on Linux Kernal !?

[mohammed hashim]

hi,

I read about the comparison between IOS, and IOS XE, that the last one is based on Linux Kernel.

although linux kernel has list of advantages, but my question is why Cisco needed to base its OS on Linux, why it did not create its own OS from scratch !! like how the original IOS was made !?

maybe I should not ask this question :) , but I am very interested to know the answer

[Leo Laohoo]

The main reason, I was told, traditional Cisco IOS are single core/CPU are unable to support multi-core environment, hence the move to Linux-based.  

[mohammed hashim]

Does this mean Cisco cannot develop multi-core OS ?

I dont have objection against this, but it will add more value to the product if it was completely done by Cisco.

[Leo Laohoo]

Does this mean Cisco cannot develop multi-core OS ?

The old Cisco IOS cannot support multi-core.  Linux-based OS can support multi-core, hence, Cisco has adapted some flavour of the Linux-based OS.  

but it will add more value to the product if it was completely done by Cisco.

I don't see any merit with this.  Whether the OS or appliance supports multi-core or single-core, Cisco products command a premium.

[Paul Chapman]

Hi -

I think there are a lot of disadvantages to private OS development, including:

• Development costs for code that meets standards of "independent invention" for existing technologies (such as SSH)
• Testing of said code
• Risks for Intellectual Property lawsuits for re-invented code
• Potential need for custom programming language development
• Loss of community support
• Exposure to "vendor unique" code exploits (think POODLE) which could damage Cisco's brand name

The goal in modern business is to bring new products to market as quickly as possible.  Why would Cisco want to create their own SSH or HTTP server code when they can take it off the shelf?  In a world where they are competing with Juniper and Arista which both provide Root access, why not offer a product that compete?

Even Apple dropped development of their own Kernel and went with BSD under the hood.  Most of their development is in the graphical overlay.

This is entirely my opinion, but the logic works.

PSC

[Joseph W. Doherty]

I'm sure Cisco could develop a multi-core OS if they chose to do so, but I suspect it's most likely a cost/benefit question that Cisco believes using a Linux kernel is the better choice.

BTW, remember often XE is the "wrapper" for running an IOS as a process.