We looked at plots of RTT vs Distance for pairs of Landmarks within 25ms and 1000km radii for Europe and N. America. Europe seemed better behaved. We looked at the network topology for the major Academic and Research (A&R) networks in N. America, i.e. Internet2, ESnet and Canarie. They are shown below.
Internet2 |
ESnet |
Canarie |
Landmarks |
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We also looked at the European Academic and Research network GEANT, together with the Landmark locations in Europe. See below:
GEANT |
European landmarks |
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Our initial results have showed an important insight about the intra regional connectivity of both regions. Our initial results are depicting a better intra regional connectivity in Europe than in North America. Both North America and Europe have many n*Gigabits links connecting one state to another in N.America or one country to another in Europe. But we want to see the state of connecitivity in few hundered miles radius around each landmark. Because in Geolocation last mile network is also very important in improving the accuracty of the technique.
In our analysis first we calculated the correlation coefficient for all landmarks within 1000 KM and 25 MS radii around them. We wanted to see the last few miles effect interms of distance as well delay. Below are the two graphs:
Plot within 1000 KM Distance Radius |
Plot within 25 MS Delay Radius |
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There are two series in each graph, white balls represent the Correlation coefficient and red balls represent the number of target landmark available within radii of each landmark. Size of the ball represent the standard deviation of delay associated with each landmark and X-axis represents the ID of the landmark or simply the row number of spread sheet of raw data. You can find spread sheets of 1000KM_Radius and 25MS_Radius correlation_coefficient_1000km_radius.xlsx and Correlation_Coefficient_25MS_Radius.xlsx(25MS file has the column names). Left Y-axis is Correlation coefficient value and right Y-axis is number of landmarks within radii. As you can clearly see the trend of number of adjascent landmarks and correlation coefficient are both high for whole Europe but they are dispursed thourghout North America. These results contradicts the perception of very good connectivity inside North America. So, we decided to do further testing of this finding.
We then took the raw data of some landmark from Europe and North America again within a radii of 1000 KM and 25 MS and plotted delay to distance graphs, we see a similar trend. Below are some sample graphs.
European Landmarks |
North American Landmarks |
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All these graphs have delay on X-axis and distance on X-axis and in all graphs with filtered caption we have applied the median filter on the values based upon delay. This was just to see the impact of removing outliers. In this case outliers are those delay values which are not following the trend. E.g. if there are three distance values 400,500,600,700 and their corresponding delay values 10,12,50,17. Here 50 is clearly an outlier. As you can observe a linear increasing trend in European landmarks which is almose absent in North American nodes. This again is depicting a similar observation that Europe has more efficient and direct last mile links in contrast to North America. Raw data is available here, Nashville_NA.rar,Atlanta_NA.rar,Paris_France.rar,Darmstadt_Germany.rar.
We are still investigating this observation against the Intra-State connectivity in North America and through other statistical analysis.