Iperf testing TCP outperforming UDP

[Ryan_G]

HI All

I have MSM422 AP,s controlled by a MSM765zl controller. We were doing some tresting and noticed that TCP significantly outperformed UDP in our iperf results.

See Below

C:\Temp>iperf -c 192.168.20.253 -i 2
------------------------------------------------------------
Client connecting to 192.168.20.253, TCP port 5001
TCP window size: 8.00 KByte (default)
------------------------------------------------------------
[128] local 192.168.11.112 port 50267 connected with 192.168.20.253 port 5001
[ ID] Interval Transfer Bandwidth
[128] 0.0- 2.0 sec 2.95 MBytes 12.4 Mbits/sec
[128] 2.0- 4.0 sec 3.00 MBytes 12.6 Mbits/sec
[128] 4.0- 6.0 sec 2.98 MBytes 12.5 Mbits/sec
[128] 6.0- 8.0 sec 2.39 MBytes 10.0 Mbits/sec
[128] 8.0-10.0 sec 2.00 MBytes 8.39 Mbits/sec
[128] 0.0-10.0 sec 13.3 MBytes 11.1 Mbits/sec

C:\Temp>iperf -c 192.168.20.253 -i 2 -u
------------------------------------------------------------
Client connecting to 192.168.20.253, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size: 8.00 KByte (default)
------------------------------------------------------------
[128] local 192.168.11.112 port 53959 connected with 192.168.20.253 port 5001
[ ID] Interval Transfer Bandwidth
[128] 0.0- 2.0 sec 184 KBytes 753 Kbits/sec
[128] 2.0- 4.0 sec 184 KBytes 753 Kbits/sec
[128] 4.0- 6.0 sec 184 KBytes 753 Kbits/sec
[128] 6.0- 8.0 sec 184 KBytes 753 Kbits/sec
[128] 8.0-10.0 sec 185 KBytes 759 Kbits/sec
[128] 0.0-10.0 sec 922 KBytes 753 Kbits/sec
[128] WARNING: did not receive ack of last datagram after 10 tries.

The iperf server is the MSM765zl!

We thought this was a little strange as generally UDP is alot faster than TCP. We thought we may have a configuration issue somewhere.

Can anyone shed some light on these results?