Severe network latency observed when communicating to another application server within same subnet.
Issue
- Network latency observed between the newly added RHEL server and the existing application RHEL server of same subnet is not more than 5 Mbps even though the NIC/link speed is of 10000Mb/s on both the ends.
- Another RHEL system of same subnet acting as a client is correctly delivering throughput of around 8 Gbps when connecting to same destination RHEL server.
- There is a Juniper 5100 switch in between the client and server.
- Throughput is tested via
iperf3
and below are the observations;
SERVER:
-------
[root@SERVER ~]# iperf3 -i 2 -s
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 10.0.0.1, port 27636
[ 5] local 10.0.0.0 port 5201 connected to 10.0.0.1 port 27638
[ ID] Interval Transfer Bandwidth
[ 5] 0.00-2.31 sec 1.62 MBytes 5.90 Mbits/sec
[ 5] 2.31-4.25 sec 1.38 MBytes 5.96 Mbits/sec
[...]
[...]
[ ID] Interval Transfer Bandwidth Retr
[ 5] 0.00-60.24 sec 35.9 MBytes 4.99 Mbits/sec 0 sender
[ 5] 0.00-60.24 sec 35.8 MBytes 4.98 Mbits/sec receiver
CLIENT:
-------
[root@CLIENT ~]# iperf3 -i 2 -t 60 -c SERVER-IP
Connecting to host 10.0.0.0, port 5201
[ 4] local 10.0.0.1 port 27638 connected to 10.0.0.0 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-2.00 sec 1.69 MBytes 7.08 Mbits/sec 0 42.4 KBytes
[ 4] 2.00-4.00 sec 1.37 MBytes 5.73 Mbits/sec 0 42.4 KBytes
[ 4] 4.00-6.00 sec 1.49 MBytes 6.26 Mbits/sec 0 42.4 KBytes
[...]
[...]
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-60.00 sec 35.9 MBytes 5.01 Mbits/sec 0 sender
[ 4] 0.00-60.00 sec 35.8 MBytes 5.00 Mbits/sec receiver
Environment
- Red Hat Enterprise Linux (Any Version)
- Juniper 5100 Switch.
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