IT Solutions Technology Blog

   Latte – for accurate network latency testing of the protocols used by most applications SockPerf (for Linux) and Latte (for Windows) produce the most relevant results

Allow Latte through the Windows firewall

C:\>netsh advfirewall firewall add rule program=C:\PC_TOOLS\LattePortable\latte.exe name=“latte“ protocol=any dir=in action=allow enable=yes profile=ANY

Run latency tests
On the receiver start latte.exe (run it from the CMD window not from PowerShell)

latte -a <Receiver IP address>:<port> -i <iterations>

Around 65000 iterations is long enough to return representative results

Any available port number is fine.

If the VM has an IP address of 10.0.0.4 the command would look like this

C:\>PC_TOOLS\LattePortable\latte.exe -a 192.168.27.105:5005 -i 65100

On the sender start latte.exe (run it from the CMD window not from PowerShell)

latte -c -a <Receiver IP address>:<port> -i <iterations>

The resulting command is the same as on the receiver except with the addition of -c to indicate that this is the client or sender

C:\>PC_TOOLS\LattePortable\latte.exe -c -a 192.168.127.105:5005 -i 65100

Note that both commands include the same IP@ the address of the receiver

I ran the test fives times and the lowest latency score I received with my default setup was a latency of 89 usec (microseconds) – that’s 89 millionths of a second

   NTttcp – when troubleshooting network performance issues it can be difficult to isolate network performance from that of other system components. When testing performance by copying a file from one system to another for example the memory and disk subsystems on both machines are being utilized to read from one machine and write to the other as well as the network. Fortunately there is a tool available from Microsoft specifically designed to test only the network

NTttcp: [-s|-r|-l|-n|-p|-sp|-ns|-to|-a|-rb|-sb|-u|-w|-d|-t|-cd|-wu|-v|-6|-wa|-nic|-xml|-ndl|-na|-hpt|-uso|-uro] -m <mappings>

-s work as a sender
-r work as a receiver
-l <Length of buffer> [default TCP: 64K, UDP: 128]
-n <Number of buffers> [default: 20K]
-p <port base> [default: 5001]
-a <outstanding I/O> [default: 2]
-rb <Receive buffer size> [default: -1]
-ndl set TCP_NODELAY socket option
-u UDP send/recv
-w WSARecv/WSASend
-rt enable roundtrip mode
-d Verify Flag
-t <Runtime> in seconds
-v enable verbose mode
-6 enable IPv6 mode
-m <mappings>

Allow NTttcp through the Windows firewall

C:\>netsh advfirewall firewall add rule program=C:\PC_TOOLS\NTttcpPortable\ntttcp.exe name=“ntttcp“ protocol=any dir=in action=allow enable=yes profile=ANY

Running NTttcp tests

Start NTttcp on the RECEIVER (run from CMD  not from PowerShell)

ntttcp -r –m [2*#num_cores],*,a.b.c.r -t 300

If the VM has four cores and an IP address of 10.0.0.4, it would look like this

C:\>PC_TOOLS\NTttcpPortable\ntttcp -r –m 1,*,192.168.27.105 -t 300

Start NTttcp on the SENDER (run from CMD not from PowerShell)

C:\>PC_TOOLS\NTttcpPortable\ntttcp -s –m 1,*,192.168.27.105 -t 300

Note that both commands include the same IP@ the address of the receiver