The pipe and the width of a bit

Bandwidth-delay product · problems P25, P26, and P27 (Kurose)

Link A → B: the file is poured into the pipe

file bits head (first bit) tail (last bit) segment magnified in the zoom view (click or drag on the pipe)

t = 0 s

Pipe capacity, R·d_prop

Bits on the link now

Maximum bits on the link during transmission

Width of a bit, s/R

Portion of the file that fits at once

Magnifier

Point of the pipe being magnified

Compare 2 Mbps and 1 Gbps

About this visualization

A view of the link as a pipe into which a file is poured, for problems P25, P26 and P27 from Kurose. It shows how many bits are on the link at each instant, the capacity of the pipe (the bandwidth-delay product), the maximum number of bits in flight and the physical width of a bit in metres, compared with a football pitch. The student changes the rate, file size, link length and propagation speed, moves a magnifier along the pipe and compares 2 Mbps with 1 Gbps. It shows that at high rates many bits fit on the link and each one takes up very little space.

Concepts: bandwidth-delay product, bits in flight, link capacity, width of a bit, transmission delay, propagation delay, transmission rate.

Formulas:

d_prop = m / s
d_trans = F / R
pipe capacity = R·d_prop
maximum bits on the link = min(F, R·d_prop)
width of a bit = s / R
file length on the medium = s·F / R
R at which one bit fills the link = s / m

Network Architecture I, Lab 1.2, problems P25 to P27 · Enrique de la Hoz, University of Alcalá · License CC BY-SA 4.0 · Source and catalogue on GitHub · DOI 10.5281/zenodo.23285664