perfSONAR User Q&A and Other Discussion

[Jason Zurawski <>]

I uploaded an additional presentation to the link that Brian sent below that 
may be helpful in learning to use these tools.  

Thanks;

-jason

On Oct 16, 2013, at 9:55 AM, Brian Tierney 
<>
 wrote:

> 
> Very strange indeed.
> 
> I'd start by doing a tcpdump capture of a good run vs a bad run, and look 
> at the tcptrace output.
> 
> See:
> 
> http://fasterdata.es.net/performance-testing/network-troubleshooting-tools/tcpdump-tcptrace/
> 
> 
> On Oct 16, 2013, at 3:07 AM, Roderick Mooi 
> <>
>  wrote:
> 
>> Hi
>> 
>> I have been trying to locate the cause of inconsistent measurements 
>> between two nodes for a few weeks now without success. The pattern I'm 
>> seeing is available at:
>> 
>> https://192.96.2.247/serviceTest/bandwidthGraph.cgi?url=http://localhost:8085/perfSONAR_PS/services/pSB&key=d9013ce7df20b8bbe45defeaeae785d6&keyR=0a0ed6c928edf28976414a2cc7e87d6f&dstIP=192.96.2.247&srcIP=196.21.48.249&dst=192.96.2.247&src=perfsonara.sanren.ac.za&type=TCP&length=2592000
>> 
>> Src-Dst is consistent but Dst-Src is not.
>> 
>> Manual tests (attached) show the same behaviour without any indication of 
>> cause - measures 941 Mbps then drops to 189 Mbps (end) and back to 941 
>> (nothing different in the logs between "good" measurements and "bad" 
>> ones). The only time I've seen something similar is when I was testing 
>> from a 10 G interface to a 1 G interface which was subsequently being 
>> flooded. In this case both interfaces are 1 G. I'm also not seeing any 
>> problems with measurements along the path or between these nodes and any 
>> other nodes. Additionally, there is very little (< 50 Mbps) real traffic 
>> between these 2 nodes.
>> 
>> Any ideas?
>> 
>> Thanks!
>> 
>> Roderick
>> 
>> -- 
>> Roderick Mooi      | SANREN Engineer
>> -- 
>> 
>>  | +27 12 841 4111 | www.sanren.ac.za
>> 
>> 
>> 
>> 
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