iperf max udp multicast performance peaking at 10Mbit/s?
I'm trying to test UDP multicast throughput via iperf but it seems like it's not sending more than 10Mbit/s from my dev machine:
C:\> iperf -c 224.0.166.111 -u -T 1 -t 100 -i 1 -b 1000000000
------------------------------------------------------------
Client connecting to 224.0.166.111, UDP port 5001
Sending 1470 byte datagrams
Setting multicast TTL to 1
UDP buffer size: 8.00 KByte (default)
------------------------------------------------------------
[156] local 192.168.1.99 port 49693 connected with 224.0.166.111 port 5001
[ ID] Interval Transfer Bandwidth
[156] 0.0- 1.0 sec 1.22 MBytes 10.2 Mbits/sec
[156] 1.0- 2.0 sec 1.14 MBytes 9.57 Mbits/sec
[156] 2.0- 3.0 sec 1.14 MBytes 9.55 Mbits/sec
[156] 3.0- 4.0 sec 1.14 MBytes 9.56 Mbits/sec
[156] 4.0- 5.0 sec 1.14 MBytes 9.56 Mbits/sec
[156] 5.0- 6.0 sec 1.15 MBytes 9.62 Mbits/sec
[156] 6.0- 7.0 sec 1.14 MBytes 9.53 Mbits/sec
When I run it on another server, I'm getting ~80Mbit/s which is quite a bit better but still not anywhere near the 1Gbps limits that I should be getting?
C:\> iperf -c 224.0.166.111 -u -T 1 -t 100 -i 1 -b 1000000000
------------------------------------------------------------
Client connecting to 224.0.166.111, UDP port 5001
Sending 1470 byte datagrams
Setting multicast TTL to 1
UDP buffer size: 8.00 KByte (default)
------------------------------------------------------------
[180] local 10.0.101.102 port 51559 connected with 224.0.166.111 port 5001
[ ID] Interval Transfer Bandwidth
[180] 0.0- 1.0 sec 8.60 MBytes 72.1 Mbits/sec
[180] 1.0- 2.0 sec 8.73 MBytes 73.2 Mbits/sec
[180] 2.0- 3.0 sec 8.76 MBytes 73.5 Mbits/sec
[180] 3.0- 4.0 sec 9.58 MBytes 80.3 Mbits/sec
[180] 4.0- 5.0 sec 9.95 MBytes 83.4 Mbits/sec
[180] 5.0- 6.0 sec 10.5 MBytes 87.9 Mbits/sec
[180] 6.0- 7.0 sec 10.9 MBytes 91.1 Mbits/sec
[180] 7.0- 8.0 sec 11.2 MBytes 94.0 Mbits/sec
Anybody has any idea why this is not achieving close to link limits (1Gbps)?
Thanks,
Tom
Check if your switch (your network cards should already support it) is accidentally not set to auto-mdix or if there is fixed value and you got a mismatch. This can cause the problems you describe, I've seen the exact same behaviour in our own network with a mismatch. Sometimes auto-mdix might not work and you should also try setting it to the same value on both sides manually.
http://en.wikipedia.org/wiki/Mdix#MDIX