I tried your suggestion. I guess you are right. This was the output when I
added -i 2 to the client side command.
root@OpenWrt:/# iperf -c 192.168.1.20 -i 2 -o root/tcp.txt
------------------------------------------------------------
Client connecting to 192.168.1.20, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.6 port 48178 connected with 192.168.1.20 port 5001
write2 failed: Connection timed out
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-962.0 sec 21.4 KBytes 182 bits/sec
However, there is some anomalous behavior. I received the final output only
after almost 15 min ( anyways, it is close to the interval mentioned above)
and not a report every 2 secs and nothing was written to the file.
Then I tried the same command. This time I didn't write the output to a
file but captured it in minicom which I have attached.
Kindly take a look at it.
In the file, in the first 2 secs 24KB is transferred and everywhere else it
is zero. However, the summary at the end reports a transfer of
29.9 KB. This is another odd occurrence.
Anyways, the iperf tcp generally reports the throughput results after
around 15 mins and the throughput is usually low in 100's of bits/sec. So,
as you pointed out i guess the connection may be lossy. However, I don't
think there would be any environmental losses as I have placed the boards
close enough.
Any ideas why this doesn't happen with UDP?
And, any views about these odd behavior and low throughput?
Moreover, if can you explain how the client-side kernel decides how much
data to send ( as you had mentioned '10 secs worth of data')
it will helpful.
Vignesh
On Mon, Jul 16, 2012 at 6:55 PM, vignesh venkateswaran
<vvinin...@gmail.com>wrote:
> I tried your suggestion. I guess you are right. This was the output when I
> added -i 2 to the client side command.
>
> root@OpenWrt:/# iperf -c 192.168.1.20 -i 2 -o root/tcp.txt
> ------------------------------------------------------------
> Client connecting to 192.168.1.20, TCP port 5001
> TCP window size: 16.0 KByte (default)
> ------------------------------------------------------------
> [ 3] local 192.168.1.6 port 48178 connected with 192.168.1.20 port 5001
> write2 failed: Connection timed out
> [ ID] Interval Transfer Bandwidth
> [ 3] 0.0-962.0 sec 21.4 KBytes 182 bits/sec
>
> However, there is some anomalous behavior. I received the final output
> only after almost 15 min ( anyways, it is close to the interval mentioned
> above) and not a report every 2 secs and nothing was written to the file.
>
> Then I tried the same command. This time I didn't write the output to a
> file but captured it in minicom which I have attached.
> Kindly take a look at it.
>
> In the file, in the first 2 secs 24KB is transferred and everywhere else
> it is zero. However, the summary at the end reports a transfer of
> 29.9 KB. This is another odd occurrence.
>
> Anyways, the iperf tcp generally reports the throughput results after
> around 15 mins and the throughput is usually low in 100's of bits/sec. So,
> as you pointed out i guess the connection may be lossy. However, I don't
> think there would be any environmental losses as I have placed the boards
> close enough.
>
> Any ideas why this doesn't happen with UDP?
> And, any views about these odd behavior and low throughput?
>
> Moreover, if can you explain how the client-side kernel decides how much
> data to send ( as you had mentioned '10 secs worth of data')
> it will helpful.
>
> Vignesh.
>
>
> On Mon, Jul 16, 2012 at 5:16 PM, Aaron Brown <aa...@internet2.edu> wrote:
>
>> Hi Vignesh,
>>
>> The way iperf works is the client makes a tcp connection to the server,
>> and sends 10 seconds worth of data. However, the client-side kernel is
>> buffering that data up, and sending it, and, in the case of loss, resending
>> it. If you have a very lossy connection, it may take far more than 10
>> seconds for the server to receive '10 seconds' worth of data. If you add a
>> '-i 2' to the server side command-line, you can see the rate it's receiving
>> the data at every 2 seconds which should help you see what's happening.
>>
>> Cheers,
>> Aaron
>>
>> On Jul 16, 2012, at 6:10 AM, vignesh venkateswaran wrote:
>>
>> I am using Iperf 2.0.4 on linux 2.6.32.10 loaded in two Mikrotik
>> Routerboards 411AR.
>> I tried to run iperf in these two boards through serial connections from
>> the
>> boards to my laptop via minicom and measure the 802.11 performance.
>> When I run iperf tcp test setting one board as server and another as
>> client, I can see only
>> the following message:
>>
>> root@OpenWrt:/# iperf -s
>> ------------------------------
>> ------------------------------
>> Server listening on TCP port 5001
>> TCP window size: 85.3 KByte (default)
>> ------------------------------------------------------------
>> [ 4] local 192.168.1.20 port 5001 connected with 192.168.1.6 port 41061
>>
>>
>> root@OpenWrt:/# iperf -c 192.168.1.20
>> ------------------------------------------------------------
>> Client connecting to 192.168.1.20, TCP port 5001
>> TCP window size: 16.0 KByte (default)
>> ------------------------------------------------------------
>> [ 3] local 192.168.1.6 port 41061 connected with 192.168.1.20 port 5001
>>
>>
>> At this point, the client hangs and the results are not displayed, not
>> even much later
>> than 10 secs. Sometimes, the results are displayed after arbitrary time
>> intervals like
>> 17.4 secs, 1092.2 secs and so on.
>>
>> UDP works fine. I get the results exactly after 10 secs.
>>
>> Can somebody identify the problem behind this and also suggest an
>> appropriate
>> solution?
>>
>>
>> Vignesh
>>
>>
>> ------------------------------------------------------------------------------
>> Live Security Virtual Conference
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>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats.
>> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/_______________________________________________
>> Iperf-users mailing list
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>> https://lists.sourceforge.net/lists/listinfo/iperf-users
>>
>>
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>> July 15-19, 2012 - Palo Alto, California
>> Hosted by Stanford University
>> http://events.internet2.edu/2012/jt-stanford/
>>
>>
>
>
> --
> V.Vignesh
> B.Tech.,(3rd Yr.)
> Electrical Engineering
> IIT Mandi
> PH: +91 8894180065
>
>
--
V.Vignesh
B.Tech.,(3rd Yr.)
Electrical Engineering
IIT Mandi
PH: +91 8894180065
root@OpenWrt:/# ls root/root@OpenWrt:/# lsroot@OpenWrt:/# iperf
--helproot@OpenWrt:/# iperf -c 192.168.1.20 -i 2
------------------------------------------------------------
Client connecting to 192.168.1.20, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.6 port 52242 connected with 192.168.1.20 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 2.0 sec 24.0 KBytes 98.3 Kbits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 2.0- 4.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 4.0- 6.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 6.0- 8.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 8.0-10.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 10.0-12.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 12.0-14.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 14.0-16.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 16.0-18.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 18.0-20.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 20.0-22.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 22.0-24.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 24.0-26.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 26.0-28.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 28.0-30.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 30.0-32.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 32.0-34.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 34.0-36.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 36.0-38.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 38.0-40.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 40.0-42.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 42.0-44.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 44.0-46.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
.
.
.
.
.
. //It goes on like this
till 602 secs and then directly jumps on to print a summary for 964.5 secs
[ ID] Interval Transfer Bandwidth
[ 3] 572.0-574.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 574.0-576.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 576.0-578.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 578.0-580.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 580.0-582.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 582.0-584.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 584.0-586.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 586.0-588.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 588.0-590.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 590.0-592.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 592.0-594.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 594.0-596.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 596.0-598.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 598.0-600.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 600.0-602.0 sec 0.00 Bytes 0.00 bits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-964.5 sec 29.9 KBytes 254 bits/sec
root@OpenWrt:/#
root@OpenWrt:/#
root@OpenWrt:/#
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
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