I did iperf test from one Linux server to another. One server is in Helsinki, other is in London and they are connected with a VPN tunnel(should be 100Mbps/100Mbps connection). I started iperf server in London(192.168.1.2) and iperf client in Helsinki(192.168.1.1). I started server with
iperf -s -u -fm command and client with
iperf -c 192.168.1.2 -fm -d -t600 -u -b 100m command. Output was fallowing:
Code:
#iperf -c 192.168.1.2 -fm -d -t600 -u -b 100m
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 0.10 MByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.1.2, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size: 0.10 MByte (default)
------------------------------------------------------------
[ 4] local 192.168.1.1 port 44456 connected with 192.168.1.2 port 5001
[ 3] local 192.168.1.1 port 5001 connected with 192.168.1.2 port 31435
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-600.0 sec 7189 MBytes 101 Mbits/sec
[ 4] Sent 5128207 datagrams
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 3] 0.0-600.2 sec 2396 MBytes 33.5 Mbits/sec 0.244 ms
3419123/5128199 (67%)
[ 4] Server Report:
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.0-600.1 sec 2411 MBytes 33.7 Mbits/sec 0.199 ms
3408321/5128207 (66%)
[ 4] 0.0-600.1 sec 299 datagrams received out-of-order
How can there be bandwidth from Helsinki to London 101 Mbits/sec when Iperf server from London raports 33.7 Mbits/sec? How can there be such a huge packet loss(67% from London to Helsinki and 66% from Helsinki to London)? I would appriciate any comments about inner workings of Iperf or explanations about Iperf output