[asterisk-users] Tired of dropouts and garbled phone calls - where to go next?

[Steve Edwards]

On Mon, 28 Oct 2013, Mike wrote:

> I found iperf (http://iperf.sourceforge.net/) to be a free and easy 
> starting point, which actually turned out to be all I needed.

I've used iperf to check bandwidth before, but never looked deeper into 
it's features. Thanks for the nudge. Maybe you can help me understand my 
results?

This is how I usually use iperf: (ws is my 'workstation,' kitchen is my 
HTPC)

-kitchen::sedwards:~$ iperf --server
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local 192.168.0.50 port 5001 connected with 192.168.0.46 port 46692
------------------------------------------------------------
Client connecting to 192.168.0.46, TCP port 5001
TCP window size:  105 KByte (default)
------------------------------------------------------------
[  6] local 192.168.0.50 port 49979 connected with 192.168.0.46 port 5001
[ ID] Interval       Transfer     Bandwidth
[  6]  0.0-10.0 sec   992 MBytes   832 Mbits/sec
[  4]  0.0-10.0 sec   867 MBytes   726 Mbits/sec

-ws::sedwards:~$ iperf --client kitchen --dualtest
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to kitchen, TCP port 5001
TCP window size:  155 KByte (default)
------------------------------------------------------------
[  5] local 192.168.0.46 port 46692 connected with 192.168.0.50 port 5001
[  4] local 192.168.0.46 port 5001 connected with 192.168.0.50 port 49979
[ ID] Interval       Transfer     Bandwidth
[  5]  0.0-10.0 sec   867 MBytes   727 Mbits/sec
[  4]  0.0-10.0 sec   992 MBytes   832 Mbits/sec

Seems reasonable for a 1Gb connection.

Playing with UDP mode, I got some results I wasn't expecting.

-kitchen::sedwards:~$ iperf --server --udp
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
[  3] local 192.168.0.50 port 5001 connected with 192.168.0.46 port 55941
------------------------------------------------------------
Client connecting to 192.168.0.46, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
[  5] local 192.168.0.50 port 47139 connected with 192.168.0.46 port 5001
[ ID] Interval       Transfer     Bandwidth        Jitter   Lost/Total Datagrams
[  3]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec   0.036 ms    0/  893 (0%)
[  5]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec
[  5] Sent 893 datagrams
[  5] Server Report:
[  5]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec   0.020 ms    0/  893 (0%)

-ws::sedwards:~$ iperf --client kitchen --dualtest --udp
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to kitchen, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size:  208 KByte (default)
------------------------------------------------------------
[  4] local 192.168.0.46 port 55941 connected with 192.168.0.50 port 5001
[  3] local 192.168.0.46 port 5001 connected with 192.168.0.50 port 47139
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec
[  4] Sent 893 datagrams
[  3]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec   0.021 ms    0/  893 (0%)
[  4] Server Report:
[  4]  0.0-10.0 sec  1.25 MBytes  1.05 Mbits/sec   0.035 ms    0/  893 (0%)

What? Why did my bandwidth dive from 800 Mbits/sec to 1 Mbits/sec?

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                              Fax: +1-760-731-3000