Attendees

Les, Umar were available b ut nobody from Pakistan was there.

General

Joun's contract has expired, most likely Joun will not continue.

HEC Report - Anjum, Amber and Imdad

Amber was working on this report. Amber should skip the missing months and put together a report from July. If Amber cannot do it, then Anjum will.

Pakistani Hosts

Anjum recommended removing monitor status from GIKI and UAAR. Les has done this at SLAC. LSE has some security issues. Anjum is investigating. He will also investigate the other monitors.

I have removed the following Pakistani hosts from the Monitoring status in the PingER meta database (NODEDETAILS) since there has been no data to gather for over 2 months.

Pingermtn.pern.edu.pk
Quest.seecs.edu.pk
Sbkwu.seecs.edu.pk
Pinger-itc.pu.edu.pk
Hu.seecs.edu.pk
Pinger.ustb.edu.pk

This follows previous removals of;
Pinger.uv.edu.pk
Pinger.giki.edu.pk
Pinger.uaar.edu.pk

If you get them working again let me know and I will add them back.

We have been unable to gather data from pinger.kohat.edu.pk for the last since the start of August. Joun says there is some Power issue in Kohat and generator is also not working according to the concerned person. The issue will be resolved in a few days

FSBD  POP has high unreachability values, which is not acceptable. They are looking into it. Backhaul network is currently leased from PTCL however in 3-4 months they will replace it with their own network. There would be no commercial traffic on it. As a result it is expected that RTT and losses will improve drastically. So next 6 months are important for observing the network performance.

TULIP 

Raja was able to successfully obtain the coordinates for several input files using all three methods i.e. (Speed of internet, Speed of light and CBI best fit). he has access to all the codes. Currently he is going through the Matlab codes and following Mathematica tutorials; this will enable him to transfer the current code to Mathematica. Before this he was not familiar with Mathematica.

He has obtained the results using the existing codes on the SEECS Server. He will modify the code after he has successfully replicated it in Mathematica. He plans to have some of the code working in a week or so.

To aid in understanding Raja requested to get a copy of the reflector.cgi source code.  Following the last meeting Les sent him reflector.cgi, reflex.cgi and EventHandler.pm

Les sent Raja a way to get the lat/longs of PingER hosts so he can make tests to these also.  Raja has plotted Alpha values against distance between nodes for Europe, Africa and N.America. The plots show that nodes further apart are more likely to have a relatively higher alpha value then nodes close to each other. Nodes further apart don't have very small Alpha values unlike nearby nodes which may have alpha values of 0.1 and below.

This might be because that nodes in close vicinity have more indirect (geographically speaking) communication path and more frequent hops. The path between nodes further apart is likely to have long continuous optical fibre segment/s. The more direct the path, the larger the alpha value.

When we are using Tulip, what we know a priori is the region the landmark is in and the min-RTT (we do not know the distance yet). Thus what we want is the alpha to yield the known distance plotted against the min RTT. Then we can choose the optimum alpha as a function of min RTT. Further if the min RTT is > some value then it is of no use and should be discarded. Obviously 0.45sec is discardable since then it is probably a satellite link, and the RTT has little to do with actual distance between landmark and target. I am guessing that Tulip will only be of use when we have large numbers of landmarks in a region (i.e. N America, Europe, Pakistan, ...) and the landmarks are in the same region as the target (probably determined by the tiering). Thus I am guessing (need further study) that if the min-RTT is > 100ms the data is of little use.

Further if the min RTT is < than some number (e.g. 10msec) then we just say the target is centered at the landmark with that min RTT and with an uncertainty of alpha*min_ RTT(ms) km, where the alpha chosen is that we have seen for min_RTT <= 10ms.

So we recommend taking the data with say 10-20ms, 20-40ms, 40-60ms, 60-80ms, 80-100ms plotting alpha vs min_rtt and plotting a trendline.

It would also be useful to have histograms for each region of the frequency of pairs (landmark to target) in each bin (0-10ms, 10-20, 20-30.. 150-100000ms.

----Original Message----

Another interesting study would be whether using different alphas (in distance[km]=alpha*min_RTT[ms]*100[km/ms]) based on the alphas found in PingER for the various regions (see for example http://www-wanmon.slac.stanford.edu/cgi-wrap/pingtable.pl?file=alpha&by=by-node&size=100&tick=daily&year=2012&month=03&from=United+States&to=United+States&ex=none&only=all&dataset=new&percentage=any) provides much benefit compared to the single current value of alpha. Also is  there a correlation of alpha vs min RTT values

Raja has start on this study when he is not busy with the Mathematica conversion.

Possible projects

Future meeting time - Les

Normal next meeting would be on ???? 2012 at 8pm in US and ???? 2012 at 8am in Pakistan.