Calculating Switch Port Costs

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Jun 3rd, 2010
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Hi guys,

I'm planning a budget for next year and trying to figure out how much to bill this department as they want to loan some of our switchports. I would like to know if anyone use a formula/method or what to consider when calculate switchport costs..

I google online and found this formula

Total Cost for each switchport =(blades required / usable slots) * chassis cost) + (blades required * cost per blade)


  • blades required = # of ports / ports per blade
  • usable slots = total number of usable slots after sup's, SFM's, etc
  • chassis cost = total cost of unpopulated, yet usable chassis, ie:  supervisor modules, power supplies, fan trays, chassis, etc.)

Any input will be greatly appreciated.


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Giuseppe Larosa Thu, 06/03/2010 - 11:58
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Hello Zappo0305,

you should consider also operational costs that include power used in a year by chassis populated with blades and supervisors and other modules.

Also the cost of the service contract to be able to receive assistance, to open cases, to perform RMA and software upgrades.

Also the cost per port of the CAPEX (initial investement) should be factorized differently:

you can charge a port for a fraction of chassis cost and for the cost of the blade that hosts it

chassis_cost/total_ports + blade_cost/#ports_in_blade

if there are 48 ports in a blade and you have installed 5 linecards you have a total of 5*48 ports in chassis

you can charge for the port:

chassis_cost / (5*48) + blade_cost/48

but this means you would like to return from cost in one year, the chassis and linecards should be used for 3 years (at least) so you could divide this by 3 or by 2.

you need to charge also for power consumption, air conditioning and service contract these are the operational costs (OPEX)

expenses for power and cooling cannot be ignored as linecards and chassis are cheaper every year but not so for energy costs.

Using power calculator or data sheet you can know how much power is needed and also you can get info about required cooling.

Hope to help



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