This is an interactive explorer for Region Based Constraint Based Geolocation (R-CBG), a technique for the geolocation of network nodes described in Section 3.1 of the 2021 research paper "Too Close for Comfort: Morasses of (Anti-) Censorship in the Era of CDNs" by Devashish Gosain, Mayank Mohindra, and Sambuddho Chakravarty.
You can use the mouse to add, remove, or drag the ■ measurement nodes and the ✖ target. ○ marks the centroid of the probe coverage regions (PCRs). The shaded polygon represents the actual borders of the region under investigation. By default, measurement nodes outside the region are ignored (the "R" in "R-CBG"), but you can choose to include them with a checkbox to compare with ordinary CBG. The "overshoot" simulates how much nodes overestimate distance based on round-trip time measurements; an overshoot of 1.10 means the radius of each PCR is 10% larger than the true distance.
Try placing measurement nodes inside and outside the region, and try moving the target inside and outside the region, to see how the technique classifies it. Heuristic values of 1 and 2 are considered "inside" the region; 3, 4, and 5 are considered "outside".
Sample layout: r-cbg layout.json.
Using only nodes inside region (R-CBG): r-cbg restricted.png.
Using nodes outside region as well: r-cbg unrestricted.png.
| ✖ | target |
| ■ | measurement node |
| ○ | centroid |
| 0 | intersection not contained in viewing window; centroid is indeterminate |
| 1 | centroid and intersection contained entirely within region |
| 2 | centroid inside region but intersection partially overlaps region |
| 3 | centroid outside region but intersection partially overlaps region |
| 4 | centroid outside region and region contained entirely within intersection |
| 5 | intersection and region do not overlap |
