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Spring, Mahajan, Wetherall:Measuring ISP Topologies with Rocketfuel

Florian Mansmann

Graduate CollegeExplorative Analysis and Visualization of Large Information Spaces

Summer School 2004University of Konstanz


Florian MansmannGraduate College - Summer School 2004

University of Konstanz

Introduction

Research field: Information Visualization

• E-mail Traffic

• Network Traffic

Chair for databases and

visualization of Prof. Keim




Aim of the Paper

• To plot a realistic map of the internet backbone

• To identify the backbone routers and their location




Motivation

• Backbone maps influence the dynamics of routing protocols

• Scalability of multicast

• Tracing and responding to denial of service attacks




Traceroutes

Routenverfolgung zu cs.washington.edu [128.95.1.4] über maximal 30 Abschnitte:

1 <1 ms <1 ms <1 ms 192.168.0.254 2 7 ms 11 ms 1 ms c-7507-v03-02.rz.uni-konstanz.de [134.34.53.1] 3 3 ms 1 ms 1 ms c-6509-v03-03.rz.uni-konstanz.de [134.34.6.113] 4 2 ms 1 ms 1 ms 129.143.47.65 5 14 ms 8 ms 8 ms Stuttgart1.belwue.de [129.143.1.7] 6 8 ms 8 ms 8 ms Stuttgart2.belwue.de [129.143.1.34] 7 8 ms 8 ms 8 ms ar-stuttgart2-ge6-0-0.g-win.dfn.de [188.1.38.53] 8 8 ms 8 ms 8 ms cr-stuttgart1-ge5-0.g-win.dfn.de [188.1.76.1] 9 21 ms 11 ms 11 ms cr-frankfurt1-po3-0.g-win.dfn.de [188.1.18.69]

10 12 ms 12 ms 12 ms dfn.de1.de.geant.net [62.40.105.1] 11 12 ms 11 ms 11 ms de1-2.de2.de.geant.net [62.40.96.53] 12 107 ms 107 ms 107 ms abilene-gw.de2.de.geant.net [62.40.103.254] 13 106 ms 116 ms 162 ms nycmng-washng.abilene.ucaid.edu [198.32.8.84] 14 159 ms 130 ms 130 ms chinng-nycmng.abilene.ucaid.edu [198.32.8.82] 15 152 ms 129 ms 157 ms iplsng-chinng.abilene.ucaid.edu [198.32.8.77] 16 141 ms 138 ms 139 ms kscyng-iplsng.abilene.ucaid.edu [198.32.8.81] 17 153 ms 150 ms 180 ms dnvrng-kscyng.abilene.ucaid.edu [198.32.8.13] 18 189 ms 178 ms 186 ms sttlng-dnvrng.abilene.ucaid.edu [198.32.8.49] 19 175 ms 185 ms 185 ms hsnp2-wes-ge0-0-0-0.pnw-gigapop.net [198.107.144.1] 20 175 ms 185 ms 185 ms uwbr1-GE3-0.cac.washington.edu [198.107.151.51] 21 175 ms 175 ms 184 ms regina-GE2-1.cac.washington.edu [140.142.155.19] 22 175 ms 182 ms 177 ms june.cs.washington.edu [128.95.1.4]

Ablaufverfolgung beendet.

• TTL Concept• Package is sent

back if TTL = 0• Next package

has TTL += 1

TTL = Time to Live




Rocketfuel Mapping Engine




Rocketfuel Mapping Engine:Selecting Measurements

• Directed Probing– Focus on traceroutes that will transit the ISP network

• Insiders

• Up/down traces

– BGP routing tables taken from Routeviews [2]

• Path Reductions– Ingress Reduction: same ingress router & destination

– Egress Reduction: same ingress & egress router

– Next-hop AS Reduction: only one trace through ISP network is likelyfrom ingress router to next-hop AS

AS = Autonomous System AS




Rocketfuel Mapping Engine:Alias Resolution

• Sending traceroute-like probe to a high-numbered UDP port, TTL=255– Reply: UDP port unreachable

– Two aliases will respond with the same source address

• Compare TTL

• IP identifier for reassemblyafter fragmentation(commonly incremented)is validated (→ schema)

• Repeat at a later time forremoving False Positives




Rocketfuel Mapping Engine:Router Identification

• Using DNS names of routers:s1-bb11-nyc-3-0.sprintlink.net

backbone New York City• Translate city codes through database• Effective in pruning out cable modems, DSL and dialup modem

pools• Infer location of routers through neighbours if DNS does not reveal

location




Rocketfuel Mapping Engine:Directed Probing

• Idea: only make traceroutes that traverse the ISP´s backbone

• Ideally: calculate by using BGP routing table

• Alternative: using Routeviews [2]

BGP = Border Gateway Protocol




Evaluation




Evaluation:Comparison with previous work




Evaluation:POP Size

POP = Point Of Presence




Resulting Maps:AT&T US




Resulting Maps:Sprintlink US




Resulting Maps:Level 3 US




Resulting Maps:Tiscali Europe




Resulting Maps:POP topology from Sprint in Springfield




References

1) Neil Spring, Ratul Mahajan, David Wetherall:Measuring ISP Topologies with RocketfuelComputer Science and Engineering,University of WashingtonSIGCOMM ’02

2) D.Meyer. RouteViews Projecthttp://www.routeviews.org

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