# Bandwidth-delay product

#1

Why is Bandwidth-delay product portrayed as complicated when it doesn’t have to be?

Here’s 2 Wikipedia examples from:

512kb/s with 900ms RTT

B x D = 512 x 10³ b/s · 900 x 10⁻³ s

= 460,800 b = 57,600 B = 57.6 kB = 56.25 KiB

2Mb/s with 50ms RTT

B x D = 2 x 10⁶ b/s · 50 x 10⁻³ s

= 100 x 10³ b = 100 kB = 12.5kB

To me that’s just overly complicated and convoluted for no reasons when the same results can be obtain with this:

(512/8).9 = 57.6 kB

or

((512/8).9)/1.024 = 56.25KiB

(2000/8).05 = 12.5kB

disambiguation:

RTT = round trip time

B · T” = kB

T” = time in seconds (900miliseconds = 0.9)

T” = time in seconds (50miliseconds = 0.05)

easy conversions:

bits to Bytes

b/8=B

ex: 460,800/8 = 57,600 B

kilo Bytes to kibibyte

kB/1.024 = KiB

ex: 57.6/1.024 = 56.25 KiB

just add 3 zero per steeps “000” when changing units b/kb/mb

ex: 57,600 B = 57.6 kB note: 57,600 third zero gets ignored 57,600 .0

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#2

That’s the same thing you just were lazy and didn’t write units.

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#3

512 x 10³ b/s · 900 x 10⁻³ s