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<span style="color: #000000">&nbsp;The>The purpose of this study is to investigate the effectiveness of tiering</span> for [TULIP|http://www.slac.stanford.edu/comp/net/wan-mon/tulip/]. (i.e&nbsp; we have a set of primary landmarks tier0 which will narrow down the target location to being in a particular region*\[1\] and then a denser set of secondary tier1 landmarks in the discovered region that can be used to get more accurrateaccurate results). Currently we are looking into two regions where we hope to use tiering, i.e. North America and Europe. We are trying to build heuristics which will.&nbsp; The choice of these two regions is since we have a relatively large number of landmarks in these regions. Landmarks in all other regions will be considered as tier0. Thus TULIP will try and locate targets in two passes. The first just uses tier0 landmarks. If the target then appears to be in North America or Europe, then a second pass is made using all the landmarks in that region, otherwise the target is determined from the first pass. The use of tiering should enable us to findreduce the region network traffic (number of landmarks pinging a particular host. the choicetarget) while retaining the accuracy of using all landmarks. The purpose of thesethe twocurrent regionsstudy is sinceto wedetermine havewhether atiering relativelyis largeeffective numberand ofhow landmarksit inshould thesebe regionsused.

\[1\] A region may be different then a geographical region