Thanks for advice.
Here is the iperf3 test results
Connecting to host
xyz.example.com, port 6000
[ 4] local XXX.XXX.XXX.XXX port 36140 connected to XYZ.XYZ.XYZ.XYZ port 6000
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 81.9 MBytes 687 Mbits/sec 0 352 KBytes
[ 4] 1.00-2.00 sec 80.5 MBytes 676 Mbits/sec 0 352 KBytes
[ 4] 2.00-3.00 sec 80.5 MBytes 676 Mbits/sec 0 362 KBytes
[ 4] 3.00-4.00 sec 79.8 MBytes 669 Mbits/sec 0 362 KBytes
[ 4] 4.00-5.00 sec 80.6 MBytes 676 Mbits/sec 0 362 KBytes
[ 4] 5.00-6.00 sec 82.0 MBytes 688 Mbits/sec 0 362 KBytes
[ 4] 6.00-7.00 sec 81.3 MBytes 682 Mbits/sec 0 362 KBytes
[ 4] 7.00-8.00 sec 80.5 MBytes 676 Mbits/sec 0 362 KBytes
[ 4] 8.00-9.00 sec 80.5 MBytes 676 Mbits/sec 0 362 KBytes
[ 4] 9.00-10.00 sec 79.8 MBytes 669 Mbits/sec 0 362 KBytes
Actually, what i was trying to ask is is there any reletion between "default
route" and "display" network on oVirt network.
Because, if there is, it might be the source of the problem.
As i wrote above, my "ovirtmanagement" and "default route" network on
the 1Gb port