More throughput than bandwidth

Lee Jaeyoung (jylee@cosmos.kaist.ac.kr)
Tue, 23 Mar 1999 16:53:23 +0900 (KST)

Hi, all.

This is my experiment environment with netperf.

source
| 35 Mbps
router1
| 2 Mbps
router2
| 100 Mbps
destination

rtt from source to destination is 35.3ms
So receiver's window size set to 88250 bytes(2Mbps * 35.3 ms) and
sender's window size set to 88250 bytes.

netperf's result is
TCP STREAM TEST to destination : histogram
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

88250 88250 88250 10.04 17.81

it's 17.81Mbps
I think that since bottleneck bandwidth is 2Mbps,
throughput is less than it.

Could you give the information about this result?
Thank you in advance.

- Jaeyoung Lee