Mathematics for Networks Workshop

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A ChallengeModeling the Dynamics of the
Inter-domain Routing in the Internet

• Mathematics for Networks Workshop
• QMUL
• March 23 2005

Timothy G. Griffin Matthew Roughan
Computer Laboratory
School of Mathematical Sciences University of
Cambridge University of
Adelaide, Australia timothy.griffin_at_cl.cam.ac.uk
matthew.roughan_at_adelaide.edu.au
http//www.cl.cam.ac.uk/tgg22/
http//www.maths.adelaide.edu.au
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Architecture of Dynamic Routing
IGP
EGP ( BGP)
AS 1
IGP
IGP Interior Gateway Protocol
Metric based OSPF, IS-IS, RIP,
EIGRP (cisco)
AS 2
EGP Exterior Gateway Protocol
Policy based BGP
The Routing Domain of BGP is the entire Internet
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BGP Operations Hard State Protocol
Establish session on TCP port 179
AS1
BGP session
Exchange all active routes
AS2
While connection is ALIVE exchange route UPDATE
messages
Exchange incremental updates
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How Many ASNs are Being Used Today?
Jan 11, 2005
Thanks to Geoff Huston http//www.potaroo.net/
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How Many Prefixes are Being Routed Today?
Jan 11, 2005
From AS 4637 Reach Network
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Data Collection GNU Zebra
router
router
BGP sessions
router
Zebra Box
BGP sessions
router
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RIPE Routing Information Service
http//www.ripe.net/ris
rrc00.ripe.net at RIPE NCC, Amsterdam, collects
default free routing updates from peers. From
October 1999. rrc01.ripe.net at LINX, London.
Collects route updates announced by LINX members.
From July 2000. rrc02.ripe.net at SFINX, Paris.
Collects route updates announced by SFINX members
. From March 2001. rrc03.ripe.net at AMS-IX,
Amsterdam. Collects route updates announced by
AMS-IX members. From January 2001.
rrc04.ripe.net at CIXP, Geneva. Collects route
updates announced by CIXP members. From April
2001. rrc05.ripe.net at VIX, Vienna. Collects
route updates announced by VIX members. From June
2001. rrc06.ripe.net at Otemachi, Japan.
Collects route updates announced by JPIX members.
From August 2001. rrc07.ripe.net in Stockholm,
Sweden. Collects route updates announced by the
NETNOD members. From April 2002. rrc08.ripe.net
at San Jose (CA), USA. Collects route updates
announced by the MAE-WEST members. From May 2002.
rrc09.ripe.net at Zurich, Switzerland. Collected
route updates announced by the TIX members. From
May 2003 to until early Feb 2004. rrc10.ripe.net
at Milan, Italy. Collects route updates announced
by the MIX members. From Nov 2003.
rrc11.ripe.net at New York (NY), USA. Collects
route updates announced by the NYIIX members.
From Feb 2004. rrc12.ripe.net at Frankfurt,
Germany. Collects route updates announced by the
DE-CIX members. From Jul 2004.
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University of Oregon Route Views Project
http//antc.uoregon.edu/route-views
Participants
AOL (NoVa) 66.185.128.48
through AS1668 APAN (tpr2-tokyo)
203.181.248.242 through AS7660 ATT
(SFO) 192.205.31.33 through AS7018
Abilene (Indiana) 198.32.8.252
through AS11537 Accretive (PAO)
207.246.129.6 through AS11608 Accretive
(SEA) 207.246.129.14 through
AS11608 Army Research Lab 192.12.65.1
through AS13 Broadwing (ADDS)
216.140.14.186 through AS6395 Broadwing
(MAE-EAST) 216.140.8.63 through AS6395
Broadwing (MAE-WEST) 216.140.2.62
through AS6395 CW USA (Santa Clara)
208.172.146.2 through AS3561 COMindico
(AU) 203.194.0.5 through AS9942
Carrier1 (NYC) 212.4.193.253
through AS8918 EBONE (EU)
192.121.154.25 through AS1755 ELI
(MAE-EAST) 208.186.154.36 through AS5650
ELI (MAE-WEST) 208.186.154.35
through AS5650 EPOCH (PAIX)
155.229.0.36 through AS4565 ESnet
(GA) 134.55.20.229 through AS293
France Telecom (NYC) 193.251.128.22
through AS5511 GLOBIX (LINX)
195.66.224.82 through AS4513 GLOBIX (New
York) 209.10.12.28 through AS4513
GLOBIX (Chicago) 209.10.12.125 through
AS4513 GLOBIX (Palo Alto)
209.10.12.156 through AS4513 GT Group Tel
(Toronto,CA) 216.18.63.137 through AS6539
Genuity (Palo Alto) 4.0.4.90
through AS1 GlobalCrossing (PAIX)
208.51.113.253 through AS3549 IAGnet
(Chicago) 204.42.253.253 through AS267
IIJ (Japan) 202.232.1.91
through AS2497 ISC (Palo Alto)
204.152.184.126 through AS3557 Intermedia
(MAE-EAST) 198.32.187.23 through AS2548

JINX (Johannesburg) 196.7.106.72
through AS2905 Jippii
(ESPANIX/Spain) 62.164.11.10 through AS8782
LINX (London) 194.68.130.254
through AS5459 Level3 (Denver)
209.244.2.115 through AS3356 MFN/AboveNet
(MAE-WEST) 207.126.96.1 through AS6461
MFS/MAE-lab (San Jose) 204.29.239.1
through AS6066 Nacamar (Frankfurt)
213.200.87.254 through AS3257 Netrail
(MAE-WEST) 205.215.45.50 through AS4006
Port80 (Stockholm) 217.75.96.60
through AS16150 RCN (PAIX)
207.172.6.221 through AS6079 RCN
(VA) 207.172.6.173 through AS6079
RIPE NCC (Amsterdam) 193.0.0.56
through AS3333 STARTAP (Chicago)
206.220.240.95 through AS10764 Sprint
(Stockton) 144.228.241.81 through AS1239
Telefonica (New York) 213.140.32.144
through AS12956 Teleglobe (London,UK)
195.219.96.239 through AS8297 Teleglobe
(PAIX) 207.45.223.244 through AS6453
Telstra (Sydney,AU) 203.62.252.26
through AS1221 TELUS (Toronto)
66.203.205.62 through AS852 TouchAmerica
() 157.130.182.254 through AS19092
Verio () 129.250.0.11
through AS2914 Verio ()
129.250.0.6 through AS2914 WCI Cable
(Hillboro, OR) 209.161.175.4 through AS14608
Williams (San Francisco) 64.200.199.3
through AS7911 Williams (San Francisco)
64.200.199.4 through AS7911 X0
(Bay Area) 205.158.2.126 through AS2828
Zocalo (Berkeley) 157.22.9.7
through AS715 blackrose.org (Ann Arbor)
204.212.44.131 through AS234 netINS
(Des Moines) 167.142.3.6 through AS5056
Many streams since 2001
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Reading the Data
www.mrtd.net
route_btoa translates binary to ASCII
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BGP Update Streams
Data from rrc01.ripe.net (LINX, London)
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A Closer Look
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High Variability
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A Closer Look
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1000 Second Bins
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Look At BGP Table Size
table size
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A Closer Look
table size
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Another Example Christmas Eve!
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A Closer Look
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High Variability, Again
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1000 Second Bins
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And Table Size
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The Challenge
Can we develop rigorous stochastic models for

• the generation of BGP updates?
• the propagation of BGP updates?
• observed BGP update streams?
• correlations between multiple data streams?
• anomaly detection?
• improving protocol design?

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This will not be easy

• Data is complex
• BGP topology is not known
• BGP policies are secret
• Implementation matters
• A network of BGP speakers acts like a large
  network of Communicating Finite State Machines
  ---- so is a large finite state transducer

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A set of BGP speakers as a Communicating Finite
State Machine
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The FSM at node 4
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The FSM at node 5
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One announce/delete at node 1can produce 52
possible outputs at node 5
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Implementation Does Matter!
stateless withdraws widely deployed
stateful withdraws widely deployed
Thanks to Abha Ahuja and Craig Labovit for this
plot.
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A few useful links
Real-time Global Routing Metrics http//www.nanog.
org/mtg-0402/ogielski.html
BGP Beacons http//www.psg.com/zmao/BGPBeacon.htm
l http//www.ripe.net/ris/docs/beacon.html
What is the sound of one route flapping? http//ww
w.cs.dartmouth.edu/mili/workshop2002/slides/griff
in_dartmouth_20020723.pdf