Estimating Internet RTTs using Recursive DNS queries

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1 Estimating Internet RTTs using Recursive DNS queries Raúl Landa, Eleni Mykoniati, Richard G. Clegg, David Griffin, Miguel Rio Communications Systems Research Group Department of Electronic and Electrical Engineering University College London

2 Motivation We are interested in estimating RTTs In a lightweight, flexible manner Between arbitrary points in the Internet Without the deployment of software probes Possible research benefits: Clustering of network prefixes by RTT between them Improved simulation of overlays and their underlying ISPs Statistical prediction of RTT values 2

3 Basic Measurement Technique We reimplement TurboKing Estimate RTT by inserting measurement point in the middle of recursive DNS queries Two phases: DNS Server Collection RTT Measurement Collection Leonard, D.; Loguinov, D.;, "Turbo King: Framework for Large-Scale Internet Delay Measurements," Procceedings of INFOCOM, IEEE, pp.31-35, April 28 3

4 TurboKing Measurement DNS Client Nameserver 1 DNS Server Nameserver 2 TurboKing Measurement Process 4

5 TurboKing Measurement: First Step 4.f9f9b8fd.measurement.net? DNS Client 4.f9f9b8fd.measurement.net? Nameserver 1 DNS Server Nameserver 2 TurboKing Measurement Process Estimating RTT to Nameserver 1 5

6 TurboKing Measurement: Second Step DNS Error DNS Client DNS Server Nameserver 2 is authoritative for 4.f9f9b8fd.measurement.net. DNS TTL = 4.f9f9b8fd.measurement.net? DNS Error Nameserver 1 Nameserver 2 TurboKing Measurement Process Estimating RTT to Nameserver 2 via Nameserver 1 6

7 Our TurboKing Implementation Written in Java 5 SE Server Discovery Thread Pool ~75 threads Throughput of ~5 new servers per second with 4 cores Measurement Thread Pool ~6 threads Throughput of ~1 measurements per second with 1 core 7

8 DNS Server Collection Random IP Addresses IP Address Lists BitTorrent Announce Messages Port 53 Probing Reverse DNS Forward DNS SOA or NS Records

9 DNS Server Collection Random IP Addresses Port 53 Probing BlueTack IP Address Blocklists Lists Nameserver Lists iplane Host Lists Top 2 Torrents BitTorrent from various Announce sites Messages e. g. The Pirate Bay, isohunt, etc. Reverse DNS Forward DNS SOA or NS Records 9

10 DNS Server Collection Word Lists Search Query Creation Google Yahoo Bing Server Hostnames Forward DNS Hostname Lists SOA or NS Records 1

11 DNS Server Collection Word lists for password cracking: 41 word lists in different languages and pertaining to different areas of knowledge Word Lists Search Query Creation Google Yahoo Bing Server Hostnames Forward DNS Queries with 2 to 4 terms Alexa Hostname Top Hosts Lists List SOA or NS Records 11 17

12 DNS Server Collection SOA or NS Records Recursive traversal of DNS tree SOA or NS Records 12

13 Server Sets DNS Server Set ~35k DNS Servers ~22k Autonomous Systems ~22 Countries Base Server Set (Recursive, Non Forwarding) ~42k DNS Servers ~8k Autonomous Systems ~18 Countries 13

14 Base Server Set 14

15 Measurement Server Measurement Point: OVH Data Centre, Roubaix (Near Lille, French/Belgian Border) 15

16 RTT Measurement Collection In our TurboKing implementation Each RTT estimation consists of 1 individual measurements performed at 1 sec intervals The minimum is taken as an estimation of the true RTT Current dataset: ~23M individual RTT measurements ~2.2M full RTT estimations More than 6M IP addresses processed 5GB in size 16

17 Estimating RTTs 15 FR!>AU!>US FR!>US!>AU

18 Estimating RTTs 15 FR!>AU!>US 1 5 FR - AU RTT FR - AU - US RTT 15 FR!>US!>AU

19 Estimating RTTs 15 FR!>AU!>US FR!>US!>AU 1 FR - US RTT 5 FR - US - AU RTT 19

20 Estimating RTTs 15 FR!>AU!>US FR!>US!>AU 1 5 2

21 Estimating RTTs FR!>AU!>US AU - US RTT US - AU RTT FR!>US!>AU 21

22 Estimating RTTs FR!>AU!>US AU - US RTT US - AU RTT FR!>US!>AU 22

23 Estimating RTTs 15 FR!>AU!>US FR!>US!>AU

24 Systematic Bias Effect of caching? (Irrespective of TTL=) 15 FR >BR >US FR >US >BR 24

25 Systematic Bias Effect of caching? (Irrespective of TTL=) 15 FR >BR >US FR >US >BR 25

26 Systematic Bias Effect of caching? (Irrespective of TTL=) 15 FR >BR >US 1 5 f(t) f(t) g(t) FR >US >BR 26

27 Systematic Bias Effect of caching? (Irrespective of TTL=) f(t) FR >BR >US pf(t) + (1 p)f(t) g(t) FR >US >BR 27

28 Systematic Bias We are currently developing a statistical technique to deal with this. Optimal point estimate for the mean RTT Leverages the knowledge of the RTT distribution between the measurement point and the first server May be extended to full distribution estimation The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/27-213) under grant agreement

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