The Delay × Bandwidth Product
Delay is measured in seconds, and bandwidth in bits per second, so the
product of the two will be a measure of bits. This represents the
maximum number of bits in transit from a sender to a receiver at one
time, and is fundamental to understanding network performance.
A few examples:
- A wireless sender is d meters from the receiver and sends
at a b/s. How many bits could be in transit at one time?
The upper bound on bits in transit
is a×d/(3×108) bits.
- The delay across an Ethernet is capped at 51.2μs and the
bandwidth is 10Mb/s. How many bits can be in transit at one time?
51.2 × 10-6s × 10 × 106b/s = 512b.
- From a fall 2007 quiz: Suppose your network bandwidth is 100Mb/s and
you share the network with a laser printer. It takes bits 3ms to get
from your PC to the laser printer. What's the largest number of bits
that could be physically in transit at one time?
100Mb/s × 3ms = 100 × 106b/s × 3 ×
10-3s = 300 × 103b = 300Kb
From here one can also go
- Up to Martens' IS 450 and Networking Page
- To Martens'
Course Page
- To Martens' home page
- To the UMBC IS Dept
- To UMBC