As reported in the Sep-Oct 2010 HEC report, path from SEECS to UET Taxila is seeing high round trip times.
Looking at the pingtable.pl data from SEECS to UETTaxila results for September and October one sees:
- The monthly average RTTs are typically 100ms.
- The min_RTTs are under 10ms.
- The IPDV are typically quite large (> 20ms)
- Also the unreachability is high measured to UETAXILa from Pakistan
- The losses from SEECS to UET Taxila are between 2.5% and 7%, which is high
Looking at the smokeping plot above, one sees min_rtts < 50ms and very large differences in min and max. If one looks in more detail especially at the region between Nov 18 and Dec 1 it is seen there is much variability. At nights the RTTs are low. This is typically when the load is low since people go to bed. Thus what we may be seeing is RTTs increasing as load goes up and some links in the path getting congested, heavy queuing ensues with attendant losses and extended RTTs.
We decided to look at the data in more detail using http://pinger.fnal.gov/cgi-bin/graph_pings.pl?src_regexp=monitor.niit.edu.pk&dest_regexp=pinger.uettaxila.edu.pk and with the file format of csv. the format of the CSV output is:
monitor.niit.edu.pk,pinger.uettaxila.edu.pk,100,10,10,60.117,86.823,138.175,3.4,22.6889,54.9,1,1602314766 i.e. Mon-name,remote-name,ping_size,sent,rcvd,min_RTT,avg_RTT,max_RTT,min_IPV,IPDV,max_IPV,Dups,unix_time+10years(GMT)
This was imported into Excel, the Unix time converted to Excel time day using Excel=Unix/(60*60*24)+"1/1/1970"
and then plot time of day versus average RTT, ipdv, max RTT. We also looked for correlations with day of the week. The results show little correlation with time of day or day of week.
This may be patrially caused by the large bins being used by graph_pings.pl. To eliminate this we will look at the half hourly data gathered into files of the form:
/nfs/slac/g/net/pinger/pingerdata/hep/data/monitor.niit.edu.pk/ping-2010-12-26.txt.gz