SME
Computer Networks · Problem type
Bandwidth-delay product
Use this for “How many bytes are in flight on a 100 Mb/s path with a 20 ms round trip?”
This is an example. Type your own values to start a new problem.
BDP (kB)
=
R (Mb/s)
×
RTT (ms)
8
Formulas
BDP
=
R
×
RTT
8
250
=
100
×
20
8
Assumptions
•
The sender keeps the link busy for a whole round trip before the first acknowledgment returns.
•
The product is the window a sender needs to fill the link; 1 kB is 1000 bytes.
•
Rates use decimal prefixes: 1 Mb/s is 10⁶ bits a second.
Step-by-step
WE KNOW
R = 100 Mb/s, RTT = 20 ms
FIND
bandwidth-delay product (BDP)
Step 1 · Find bandwidth-delay product (BDP)
Use BDP = R × RTT ÷ 8
Mb/s times ms gives kilobits; 8 bits a byte turn them into kB.
BDP
=
100
×
20
8
BDP
=
2,000
8
BDP = 250 kB
Check
Put the numbers back in. Both sides should match.
250
=
100
×
20
8
✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
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