You must take the cost of procurement as the starting point.
What does the software cost? What does the hardware it will require cost?
Next, what is the cost of managing this and keeping it running?
What do you have to pay an engineer or DBA that can administer the product? How much are upgrades? What about vendor support? Will you have to retrain people to manage this product?
What is the projected life span of the product?
TCO = [(procurement cost) + (management cost) x life span ] x number of units
If you can run the numbers for the commercial package and compare them to the open source package, you should be able to see this to your managers.
Example - fire wall
Linux vs. Nokia Checkpoint Device
Procurement Costs
Linux - software = $0
- hardware = $0 (assuming cast off workstation recycled as firewall)Nokia Device = software & hardware come bundled $15,000 ____________________________________________________________ Management Costs
Engineer to run linux firewall competently - $85,000 Engineer to run Nokia Device competently - $75,000
Upgrageds Linux - $0 Nokia Device - free first three years then $1000/yr
Vendor Support RedHat - $2500/year (24x7 support) Nokia Device - free first three years then $1000/yr
Retraining Employees (3 employees) RedHat - $1000 per employee Nokia - Limited training available from sales staff ____________________________________________________________
Lifespan 5 years
Number of Units 2 (external and DMZ)
_____________________________________________________________
Linux TCO = [(0) + 3*1000+ (85000+ 2500) x 5 ] x 2 = $881,000
Nokia TCO = [(15000)+(75000)x5+2*1000{2 additional years of updates}+2*1000{2 additional years of support}]x2 = $788,000
That's how you make your case to management if you want to do it based on TCO.
-- Thanks,
Ms. Jimi Thompson, CISSP, Rev.
"Those who are too smart to engage in politics are punished by being governed by those who are dumber." --Plato
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