Backplane vs Switching capacity

[Jonn cos]

Hi All,

I was reading H3C 7500 specs (due to some competitive requirement) and found that they have listed backplane and switching capacity separately

http://www.h3c.com/portal/Products___Solutions/Products/Switches/H3C_S7500_Series_Switches/Detail_Material_List/200701/194478_57_0.htm

The H3C S7500 Series switch deploys Salience^TM III series engines with maximum switching capacity 768Gbps, with throughput as much as 432Mpps, while the backplane capacity reach 1.68Tbps.

I thought switching capacity and backplane capacity are same, but it seems they arent. I know its not cisco related but i am sure its general, can someone please help me understand this ?

[Muhammad Thanveer]

Hello John,

Backplane and switching capacities are slightly different. Backplane capacity is similar to bus speed in a computer. 
It defines the bandwidth of the module-to-module interconnect in large multi-module switches. 

Backplane speed is just one component of total speed, it means total backplane throughput of a switch would be the sum of the port speeds.

Switching speed is the rate that a port-to-port transfer can be made.

BR

Thanveer

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