How to test application bandwidth usage ?

Hi..
I do some analysis about application usage of bandwidth ... Let say we test firewall.cx website bandwidth usage..

Calculating application bandwidth

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- go to site-perf.com
- the result as below :

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Assume Firewall.Cx internet bandwidth

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- Let say you are using 100Mbps lease line to surf all the website to public

- Total website bandwidth usage for firewall.cx = 251 484 Byte

- 100 Mb = 12 500 000 Byte

- Total lease line bandwidth / application bandwidth = total concurrent user

- 12 500 000 / 251 484 = 49 concurrent user

My Question

- Is it the wright way to plan & calculate application bandwidth usage?
- I need this information before proposed to my Bos to upgrading exisitng internet line at our company..

Please advice.

Tq

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