mPlane – Building an Intelligent Measurement Plane for the Internet A quick overview

2 A complicated technology… The internet is a key infrastructure where different technologies are combined to offer a plethora of services. It’s horribly complicated. We sorely miss the technology to understand what is happening in the network and to optimize its performance and utilization.

3 mPlane About the design and demonstration of an “intelligent measurement plane for the Internet”  Large scale  Collaborative FP7 Integrated Project (IP)  3 years 2years  16 partners  11.2+Meuros

4 The consortium Marco Mellia POLITO Saverio Nicolini NEC Dina Papagiannaki Telefonica Ernst Biersack Eurecom Brian Trammell ETH Tivadar Szemethy NetVisor Dario Rossi ENST Fabrizio Invernizzi Telecom Italia Guy Leduc Univ. Liege Pietro Michiardi Eurecom Pedro Casas FTW Andrea Fregosi Fastweb 3 operators 6 research centers 5 universities 2 small enterprises coordinator

5 mPlane in a picture Repository and Analysis Layer Measurement Layer Module 1 Module 2 Module N mInterfac e mProbe 1mProbe 2mProbe NlegacyProbe 1legacyProbe 2legacyProbe N legacyDB 1 legacyDB 2 legacyDB N mPlane Repository Supervisor Intelligent Reasoner Analysis Modules WP4 WP3 WP2 Question(s) Answer(s)

6 Some of mPlane use cases Anomaly detection and root cause analysis in large-scale networks (Polito + FTW) Quality of Experience for web browsing (Eurecom) Mobile network performance issues (Telefonica) Verification and certification of service-level agreements (FUB) Estimating Content and Service Popularity for Network Optimization (Alcatel + Polito + NEC) Etc. FOCU S

Monitoring DNS mapping strategies Public DNS Resolvers: Friends or Foes? Resolver Choice Implications on End-Users Performance (submitted to CCR)

8 The promise of Public DNS resolvers Public DNS resolvers (e.g., OpenDNS e Google DNS) promise better browsing experience to end-users About 20% of customers have switched to public resolvers This is proven to be overstated especially for CDN content  [IMC 10] Comparing DNS resolvers in the Wild  [IMC 12] Content Delivery and the Natural Evolution of DNS: Remote DNS Trends, Performance Issues and Alternative Solutions  The reason being sub-optimal geographical mapping Authoritative DNS resolvers see the recursive resolver, not the end-host originating the request

9 Extended DNS Client Subnet (ECS) A DNS extension proposed by the “A Faster Internet” consortium (  Google, OpenDNS, and Edgecast are part of the consortium  According to the official website (and active probing) they already adopt the solution DNS recursive resolvers append the user’s IP when issuing requests Authoritative DNS resolvers perform the mapping wrt the user IP  PROS: it helps solving the geographical mapping issue  CONS: it further complicates mapping strategies

10 Research questions and objectives How much public resolvers affect end-users performance? Does ECS present any advantage? Passive analysis  Months of Tstat HTTP logs from more than 35k ADSL customers  Each HTTP transaction reports also Maxmind organization name of the server IP address DNS resolver used to map the hostname to an IP (*) Focus on popular services as a whole, i.e., not simple “benchmarking” content [IMC12] DNS to the Rescue: Discerning Content and Services in a Tangled Web (*)

11 Apple iTunes and App Store content download (ECS off) (For instance, a907.phobos.apple.com  Akamai cache) Consider object larger than 500kB  measure the download rate Download Rate [kb/s] kb/s kb/s Whole April th 50 th 75 th Download Rate [kb/s] Whole November th 50 th 75 th !!!

12 content (ECS on) Narus Inc. - Nov 3rd, 2013 Each point compares percentiles of daily distributions Each point compares percentiles of daily distributions 5 popular services (AddThis, Gravatar, Weborama, Tumblr, and Red-Tube)  Account for 50% of the EdgeCast volume  By active probing, all service present ECS enabled Consider objects smaller than 500kB  measure the download time  Compare  differences over time (i.e., difference between distributions %- tiles) !!!

13 Edgecast DNS mapping Check the min RTT between the probe and the CDN node…

14 Conclusions (so far) We haven’t found strong evidences that public resolvers have significant benefits for end users … not even when ECS seems to be enabled DNS Pre-feching reduces the important of very fast resolution Next steps:  Other services (Facebook, YouTube, etc.) possibly supporting ECS (but are not easy to spot)  More (and new) data  “Anomaly detection” of unexpected variations in DNS mapping

15 ?? || ## Alessandro Finamore – Politecnico di Torino