Attendees

Anjum, Kashif, Raja, Umar, Les. Joun is travelling.

General

Joun is still with us, so is Kashif.

  • Joun is looking after the Pakistani nodes, also asked to look at rest of nodes, will let know if there are problems, good learner but not skilled at programming.
  • Kashif was on the management side, deal with HEC and University people. Now work on HEC report. PhD student.

Arshad will be at SLAC on Sept 26th. Deploy another node in Faisalbad University. Have a POP node, this will give us more information.

HEC Report - Anjum, Amber and Imdad

Kashif is taking this over.

Pakistani Hosts

LSE had 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.

The IP address for Kohat has been changed, it is now working.

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. Went from unrelaibility then to long RTT. Not moved yet. Kashif will look into long RTTs.

Non Pakistani Hosts

The Nepali, Jordan (SESAME), and another in Sri Lanka were reported down by Joun.  Sri Lanka has only been down a few days,  I have sent email to Nepal and Jordan.

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. When we understand the code it may make sense to use a modified outer circle. I.e. instead of distance (radius in km)= 100km/ms*min_RTT(ms), use distances(radius in km)=alpha_max*100km/mx*min_RTT(ms) where alpha_max is the maximum alpha for landmarks to target in a given region. This is on hold until we grasp on ths statistics

Raja 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.  Any progress?

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 than 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. 5msec) 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.

It might help to look at subsets of  the data with say 0-5ms, 10-20ms, 20-40ms, 40-60ms, 60-80ms, 80-100ms plotting alpha vs min_rtt and plotting a trendline for each subset .

Raja has created histograms for each region of the frequency of pairs (landmark to target) in each bin (0-10ms, 10-20, 20-30, 30-50, 50-100ms)

Raja is verifying that the coordinates in the Tulip landmarks file make sense. There was an error for SDSC (minus sign missing). Progress?

Looking at Raja's most recent spreadsheet. There is something bad with the UK.DL monitoring site. the alpha does not appear to have much of a correlation with min_RTT for N. America and Europe. WE may be able to use the ranges (min and max) with the Constrained CBG. Don't bother with Africa. Should add Pakistan and possibly Far East.

Possible projects

Future meeting time - Les

Normal next biweekly meeting would be on September 26 2012 at 8pm in US and September 27 2012 at 8am in Pakistan.

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