Multipath Detection with RIPE Atlas Stephen Strowes - - PowerPoint PPT Presentation

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Multipath Detection with RIPE Atlas Stephen Strowes - - PowerPoint PPT Presentation

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Multipath Detection with RIPE Atlas Stephen Strowes <sds@ripe.net> | March 14th, 2018 | AIMS 2018 a.k.a. cant we just use RIPE Atlas for this? Stephen Strowes <sds@ripe.net> | March 14th, 2018 | AIMS 2018

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Stephen Strowes <sds@ripe.net> | March 14th, 2018 | AIMS 2018

Multipath Detection with RIPE Atlas

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Stephen Strowes <sds@ripe.net> | March 14th, 2018 | AIMS 2018

a.k.a. can’t we just use RIPE Atlas for this?

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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Paris Traceroute on Atlas

  • API docs:



 
 
 
 
 
 


  • default: 16
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Paris Traceroute on Atlas

  • Atlas can cycle through [0 .. 64] distinct flow

IDs

  • Modifies:
  • destination port field in UDP
  • checksum field in ICMP
  • Of course a measurement can define an

address family (4/6) and transport (ICMP, UDP, TCP)

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SLIDE 5

Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Regardless…

  • Multipath observations on Atlas?
  • Rough comparison:
  • Choosing targets to match Kevin’s measurements
  • Using an Atlas probe within a matching ASN as above
  • What do we see?
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Apples to Apples part I

  • From: probe 6278
  • To: 125.155.82.17
  • Full cycle of flow IDs
  • UDP transport
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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probe 6278 -> 31.13.64.6

  • UDP: 91 IPs in path observed, 165 edges
  • ~80% of the IPs without being smart
  • ~20-25% of edges
  • No alias resolution etc
  • 4600 traceroute probes sent
  • [ICMP sees fewer of the above]
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SLIDE 8

Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Apples to Apples part II

  • From: probe 6278
  • To: 31.13.64.6
  • Full cycle of flow IDs
  • UDP transport
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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probe 6278 -> 125.155.82.17

  • UDP: 87 IPs in path observed, 147 edges
  • ~72% of the IPs
  • ~20% of the edges
  • 2900 traceroute probes sent
  • [ICMP sees a straight line]
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Shortcomings

  • Current implementation is slow to iterate
  • Can iterate measurements to get pretty far

with the Atlas API, but it’s a lot of work

  • We cycle through a small set of flow IDs, with

no configuration for other fields to modify

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SLIDE 11

Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Shortcomings

  • No smarts built-in to avoid repeatedly

measuring hops with only one link

  • You can throw away your statistical

guarantees

  • Finally, 70% of Atlas platform is behind a NAT
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Ongoing

  • Investigating more structured approaches to

performing multipath detection with Atlas

  • Expand the set of paris IDs available
  • … up to a smarter MDA measurement type?
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Stephen Strowes <sds@ripe.net> | AIMS 2018 | March 14th 2018

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Q