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(Trilateration Utility for Locating IP hosts)

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Start TULIP What is TULIP Lateration Other ways to locate hosts Uses of TULIP Requirements Landmarks Problems

What is TULIP

TULIP is a Java application being developed by the MAGGIE-NS team from the National University of Sciences and Technology (NUST) Institute of Information Technology (NIIT) and the Stanford Linear Accelerator Center (SLAC) Internet End-to-end Performance Monitoring (IEPM) project. TULIP's purpose is to geolocate a specified target host (identified by IP name or address) using ping RTT delay measurements to the target from reference landmark hosts whose positions are well known. Knowing the speed of light in fibre or copper (roughly 0.6*c, we use 1ms. is equivalent to 100km), the minimum ping RTT measurement from each landmark site gives a rough estimate of the fibre + copper cable distance of the landmark from the target host. Lateration is applied on these distance estimates to estimate the position of the specified host on the globe.


Lateration is the calculation of position information based on distance measurements. Multi-lateration computes the position of an object by measuring its distance from multiple reference positions. Calculating an object's position in two dimensions requires distance measurements from 3 non-collinear points (hence Trilateration).

Other ways to locate a host

If you want to find the great circle distance and know the latitude and longitude coordinates of the two ends then you can use the Movable Type Scripts web page. World Gazeteer provides access to data with lat/longs, cities, countries & populations ( download data). You can also make a name server lookup for a host, or if you don't know the exact name try DomainSurfer. There is also an Atlas of Cyberspace that provides maps and graphic representations of the geographies of the new electronic territories of the Internet, the World-Wide Web and other emerging Cyberspaces and the Corpex sponsored Cyber Geography Research.

Some Uses of Geolocation

Requirements for TULIP:

Java Web Start must be installed on your system. It requires a configuration file that provides the name and location of each landmark, the URLs for the ping and traceroutes. At SLAC this is kept at /afs/slac/www/comp/net/wan-mon/tulip/Sites.txt.


For hosts in the world at large it is important to have landmarks that enable the host to sit within a triangle of landmarks 1,2. Thus we are very interested in getting more landmarks that cover the world. The requirement on a landmark is to install a reverse traceroute/ping server (see Traceroute Servers for HENP & ESnet) on a web server at the landmark site. Instructions for downloading and installing the traceroute server are available at After it installed please let us know so we can add the landmark to the TULIP configuration file (see the bottom of this page for our email addresses).



1 "An Empirical Evaluation of Landmark Placement. on Internet Coordinate Schemes." Sridhar Srinivasan. Ellen Zegura.
2 "Geometric Exploration of the Landmark Selection. Problem." Liying Tang and Mark Crovella
Contacts: Faran Javed Chawla (NIIT) <faran.javed at> and Les Cottrell (SLAC) <cottrell at> as part of the MAGGIE-NS team
NUST Institute of IT 2006