Bandwidth-Delay Product
networking, tcp
Solution
It depends what you mean by "delay". If delay is the round trip time (RTT) then you wouldn't multiply it by two. Presumably, in the formula you are looking at, the delay is the unidirectional transmiasion time, so you multiply it by 2 to estimate the RTT.
One RTT is the earliest time you could get an acknowledgement back for the first bit you transmitted, so that's why your window should be that big in order to fill the pipe.
Problem
Its given that the bandwidth-delay product defines the number of bits that can fill the link. The sender should send a burst of data of (2*bandwidth*delay) bits. I am not getting why the term bandwidth*delay multiplied by 2.Please Explain the reason???