Locating hosts by TULIP (Trilateration Utility for Locating IP hosts) Prepared by: Les CottrellSLAC, Faran JavedNIIT, Shahryar KhanNIIT,Umar KalimNIIT Internet2 fall members meeting San Diego, October 2007 This talk will define the Digital Divide, show why it matters, and then go on to show how we can measure it in terms of Internet performance. Results from the measurements will show worldwide improvement trends in round trip times as links move from satellite to terrestrial, throughput as the speed of links improve, losses and reachability as robustness is increased. Comparing the performance for developed vs. developing regions will show which regions are catching up, keeping up, or falling further behind, and how well the Internet performance correlates with UN and ITU development indices. We will close out with some results from case studies on Africa and South Asia. http://www.slac.stanford.edu/grp/scs/net/talk07/i2mmfall07.ppt

Purpose Geo locate a host given its name or address Uses ping (RTT) measurements from landmarks landmarks at known locations worldwide RTT roughly proportional to distance in many cases Distance (km) = alpha * RTT (ms) Velocity light in fibre ~ 0.6c or 1ms for 100km. Use min RTT to reduce effect of queueing Using distance from RTT, triangulate to get lat/long

Goals Platform agnostic (Java & Perl (CGI)) Open, non-proprietary (cf. Traceware, Edgescape) Minimize security concerns Include developing regions Sustainable robust service Minimize manual effort (keep databases current) Provide an API to enable other applications We also wanted to verify the locations of the hosts in the PingER database.

Uses of Locating Hosts Choose content to send (e.g. language, local store) Security: pin-point suspicious hosts Where to get replicated service (e.g. Grid) Information for maps (e.g. visualroute) Efficiency of routing For Digital Divide & world-wide collaborations

How to get the location They are complementary Database (e.g. DNS, whois, Geo IP tools) Hard to keep up, may require subscription, maybe inaccurate, out-of-date or incomplete Traceroute and heuristics on names (Visual traceroute) RTTs (e.g. Octant from Cornell, Constraint based Geolocation from Belgium/Boston U) Neither are active any more (student projects pointing the way?) They are complementary Each has own strengths and weaknesses Could/should be used together to validate each other and make corrections.

Simple Methodology (1) Client Landmarks Reflector Target Client loads (Java Webstart), runs Java applet gets target from user Client requests Reflector to get pings to target Reflector requests Landmarks to ping target, Landmarks Ping target Reflector (web server running CGI script) Target

Simple Methodology (2) Client Landmarks Reflector Target Client analyses data, visualizes and provides to user Reflector send RTTs back to Client Landmarks send results back to Reflector Landmarks Ping target Reflector (web server running CGI script) Target

Landmarks Want good geographical coverage for world. Need to be reliable, answer No connection, timeouts, 100%loss (24 excellent PlanetLabs) Respond quickly Not satellite connection Not a proxy SLAC/PingER reverse traceroute servers ~ 60, but more diverse, see www.slac.stanford.edu/comp/net/wan-mon/traceroute-srv.html PlanetLab ~ 150 landmarks Mainly in N. America and Europe

Security (lots of concerns) Can be used for DoS attacks against a target Looks like a potential scan of the target vs many hosts Target ICMP replies to a large number of hosts CGI scripts (Perl) needs to be well vetted for holes Ability to discover & then blackhole abusers Only one TULIP client per host Landmarks and reflector both limit the number of running requests Centralized logging of all requests and results, plus analysis Look for anomalies Also discovers what landmarks are failing, who is requesting Possible privacy problems if locate a person’s host accurately (could add fuzz)

Problems Geostationary satellite connections 24Kmiles => RTT >370ms, heavily used in C. Asia and Africa IP name refers to multiple hosts (e.g. Google, Akamai, root name servers) in many locations Hosts move, have proxies etc. Indirect routing so RTT !~ distance E. Asia vs. Australia seen from US Security concerns Duration for measurements (50 seconds to complete, results start arriving earlier) Optimizing # of parallel requests from reflector, timeouts, tiering, remove poor landmarks Optimizing alpha in distance (km) = alpha * RTT (ms). Optimizing the choice of tier 0 landmarks, reliable & at edges, want very few, yet few false positives or mistakes N. America: SLAC/CA, BNL/NY, AMPATH/FL, TRIUMF/CA(Vancouver), Winnipeg/CA, Houston, Saint Louis, Chicago Europe: CERN/CH, ICTP/IT, DL/UK

Demo of early version www.slac.stanford.edu/comp/net/wan-mon/tulip 2 sets of landmarks: PlanetLabs & SLAC/PingER type Enter host name or address & Locate Site Raw results in Ping Results window Visualize results in map

Evaluation of early version Use ~600 PingER hosts with “known” lat/long Hosts in over 130 countries Also validates PingER data Need landmarks close to targets 50% accurate to within 200 km, 70% within 1000km Ouch, not very successful, worse with RTT

Alpha = 48.54 RTT/Dist (km/ms) Improvements Add more landmarks for better coverage: PlanetLab & more SLAC landmark deployment (especially in developing world) Understand outliers, correct PingER dB Outliers: Multi-homed, e.g. yahoo, root servers, Move: e.g. supercomp Not at site of ASN: e.g. 134.79 SLAC host in Arizona Indirect routing: SFO-LA-SEA-VIC Alpha = 48.54 RTT/Dist (km/ms)

Look at Alpha Set alpha to right value to get correct distance from RTT and look at distributions Done for major US to N. America & major Europe to Europe sites

In progress Have stable version 1 Adding: www.slac.stanford.edu/comp/net/wan-mon/tulip/ Adding: More landmark, filter out non-working instances Integrate PlanetLabs & other landmark databases Improved map visualization and zoom Optimizing timing parameters (parallel streams, timeouts, landmark choices, alpha …) Faster landmark response GeoIP Tool estimates http://www.geoiptool.com/ Tiering Redo evaluation, compare with other methods

Tiering Want to reduce the traffic hitting a target First find region target is in (tier 0 search) Use few best landmarks in region Highly responsive, at edges of region Determine most likely region (N. America, Europe, the rest) Then if client wants more detail use all landmarks in region to pin-point target Take 1/10 time for tier 0s vs all for N. America

More information/Questions Acknowledgements: PlanetLab, SLAC reverse tracroute servers hosted in Africa, E. Asia, Latin America, Middle East, Russia, S. Asia TULIP Home Page: http://www.slac.stanford.edu/comp/net/wan-mon/tulip/ PingER (driving reason for tool) www-iepm.slac.stanford.edu/pinger, TULIP 1st Prize at All Asia Softec 2007 http://www.niit.edu.pk/press/pages/releases/tulip.php