Quaking Tables: The Taiwan Earthquakes and the Internet Routing - - PowerPoint PPT Presentation

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Quaking Tables: The Taiwan Earthquakes and the Internet Routing - - PowerPoint PPT Presentation

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Quaking Tables: The Taiwan Earthquakes and the Internet Routing Table Alin Popescu, Renesys Corp APRICOT Bali 2007 Todd Underwood, Renesys Corp Earl Zmijewski, Renesys Corp Overview Large earthquakes hit Luzon Strait, south of Taiwan on

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SLIDE 1

Quaking Tables: The Taiwan Earthquakes and the Internet Routing Table

APRICOT Bali 2007

Alin Popescu, Renesys Corp Todd Underwood, Renesys Corp Earl Zmijewski, Renesys Corp

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SLIDE 2

February, 2007

Quakes and Routing Page 2

Overview

  • Large earthquakes hit Luzon Strait, south of

Taiwan on 26 December 2006

  • Seven of nine cables passing through the

straight were severed

  • We review the event from a perspective of the

Internet Routing tables

  • Routing outages occurred, significant congestion

was reported, instability persisted

  • Recovery was delayed and uneven
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SLIDE 3

February, 2007

Quakes and Routing

Submarine cables in East Asia

Page 3

  • Two of nine cables not

impacted:

  • Asia Netcom's EAC
  • Guam-Philippines
  • All cables reported

repaired as of February 14, 2007 (source: Office of the

Telecommunications Authority of Hong Kong)

Page 3

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SLIDE 4

February, 2007

Quakes and Routing

Submarine cables in East Asia (2)

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SLIDE 5

February, 2007

Quakes and Routing

Repairing submarine cables is difficult!

Page 5 Image credit: Alcatel Page 5

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SLIDE 6

February, 2007

Quakes and Routing

Definitions: Outage, unreachable, unstable

Page 6

  • A network outage occurs when routes to the network

are withdrawn by a large number of BGP routers worldwide.

  • In this case if no less specific route is available, the

network is unreachable and effectively disconnected from all or parts of the Internet.

  • Unstable networks are not completely disconnected,

but show frequent changes in network routing paths or alternating announcements and withdrawals (route flapping) – serious packet losses.

Page 6

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SLIDE 7

February, 2007

Quakes and Routing

Timeline

  • Six earthquakes of magnitude 5.0 or higher hit the

Taiwan region (all times UTC):

  • 12/26 12:26:21

7.1 -- main quake

  • 12/26 12:34:14

6.9

  • 12/26 12:40:22

5.5

  • 12/26 15:41:44

5.4

  • 12/26 17:35:10

5.4

  • 12/27 02:30:39

5.6

  • 12/28 16:51:16

4.4

  • Outaged prefixes ramp up from 400 to almost

1200 from the first quake through seventh

Page 7

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SLIDE 8

February, 2007

Quakes and Routing

Timeline (2)

  • 03:31 27 Dec 2006: 60 mins after the last quake,
  • utaged network count spikes to 4k
  • The “spike” is short-lived (< 2 hrs) but > 2k

prefixes out for 6 hours.

  • 31 Dec 2006 12:00: Outages return to pre-quake

levels.

  • Instability level remains high into January.

Page 8

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SLIDE 9

February, 2007

Quakes and Routing

Data Collection Infrastructure

  • 165+ peering sessions from 105+ different ASNs
  • In this talk, we focus on East Asian prefixes only

Page 9

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SLIDE 10

February, 2007

Quakes and Routing

  • Disasters Have Signatures
  • Sharp onset associated with some real-world

event

  • Slow return to baseline
  • Varies considerably
  • Power outages: fast
  • Major natural disasters, much slower
  • Noise in the recovery (not in the onset)

Page 10

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SLIDE 11

February, 2007

Quakes and Routing

  • Power (Northeast US, 2003)

Page 11

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SLIDE 12

February, 2007

Quakes and Routing

  • Hurricane (Katrina, 2005)

Page 12

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SLIDE 13

February, 2007

Quakes and Routing

The Pattern of the Taiwan Quakes

  • Ramping up outages and spikes in instabilities
  • Gradual increase in number of outages after

major quake in Dec. 26

  • Big spike in outages/unstables associated with

smaller quake on Dec. 27

  • Recovery typically noisy
  • Pattern was probably affected by the number of

different cable systems involved – this is not really one event but at least seven.

Page 13

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SLIDE 14

February, 2007

Quakes and Routing

  • Outages & Quakes – 3 Day

Page 14

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SLIDE 15

February, 2007

Quakes and Routing

  • Outages & Quakes – 10 Day

Page 15

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SLIDE 16

February, 2007

Quakes and Routing

  • Outages by Country – 3 Day

Page 16

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SLIDE 17

February, 2007

Quakes and Routing Page 17

Why India?

Major subcontinent bandwidth heads East

Image credit: Asia Netcom

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SLIDE 18

February, 2007

Quakes and Routing

  • Outages by Country – 10 Day

Page 18

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SLIDE 19

February, 2007

Quakes and Routing

  • Outages by Country – Peak

Page 19

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SLIDE 20

February, 2007

Quakes and Routing

Outages by Origin ASN – 3 day

Page 20

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SLIDE 21

February, 2007

Quakes and Routing

Outage by Origin ASN – 10 day

Page 21

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SLIDE 22

February, 2007

Quakes and Routing

Outages by Origin ASN – Peak

Page 22

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SLIDE 23

February, 2007

Quakes and Routing

  • Instability Metrics
  • Use algorithm described in

http://www.nanog.org/mtg-0402/ogielski.html

  • PenaltyBox(T,K,H,C): the number of globally

routable prefixes at time T that have flap penalty K, using the classic flap dampening algorithm with half-life of H and ceiling of C.

  • Reasonable: H=600s, C=15, K={0,…,C}.
  • (Basically flap-dampening algorithm for scoring

the “penalty” of a prefix).

  • Shown in graphs are pfxs w/ inst >= 3

Page 23

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SLIDE 24

February, 2007

Quakes and Routing

  • Unstables & Quakes – 3 Day

Page 24

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SLIDE 25

February, 2007

Quakes and Routing

  • Unstables & Quakes – 10 Day

Page 25

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SLIDE 26

February, 2007

Quakes and Routing

  • Unstables by Country – 3 Day

Page 26

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SLIDE 27

February, 2007

Quakes and Routing

  • Unstables by Country – 10 Day

Page 27

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SLIDE 28

February, 2007

Quakes and Routing

  • Unstables by Country – Peak

Page 28

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SLIDE 29

February, 2007

Quakes and Routing

Unstables by Origin ASN – 3 day

Page 29

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SLIDE 30

February, 2007

Quakes and Routing

Unstables by Origin ASN – 10 day

Page 30

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SLIDE 31

February, 2007

Quakes and Routing

Unstables by Origin ASN – Peak

Page 31

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SLIDE 32

February, 2007

Quakes and Routing

  • Winners & Losers: By Country
  • Used maximum to median ratio of outages and

unstable networks

  • Worst Impacted:
  • China, Hong Kong
  • Least Impacted:
  • Korea, Japan, Malaysia

Page 32

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SLIDE 33

February, 2007

Quakes and Routing

  • Winners & Losers: By Country (cont'd)

HK TW ID VN CN IN SG PK TH BD PH MY JP KR 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Max/Median Outages by Country

Country Max/Median Outages

CN HK PH SG ID BD IN TH TW VN JP PK MY KR 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Max/Median Unstables by Country

Country Max/Median Unstables

Page 33

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SLIDE 34

February, 2007

Quakes and Routing

Impacted ASNs

  • Examined Asian prefixes outaged and/or unstable

by origin AS – 1667 ASNs impacted:

  • China Telecom: AS4134, AS4812 (CN)
  • Sify: AS9583 (IN)
  • VSNL: AS4755 (IN)
  • Bharti BT Internet: AS9498 (IN)
  • PT Telekomunikasi: AS17974 (ID)
  • CNC Group (AS4808, AS4837) (CN)
  • Smart Broadband: AS10139 (PH)
  • INDOSAT: AS4795 (ID)

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SLIDE 35

February, 2007

Quakes and Routing

  • Winners & Losers by ASN (cont'd)

9381 4515 4657 24138 9829 9394 9929 10091 17488 9304 4795 10139 4837 4808 17974 4812 9498 4755 9583 4134 500 1000 1500

# of prefixes

9381 4515 4657 24138 9829 9394 9929 10091 17488 9304 4795 10139 4837 4808 17974 4812 9498 4755 9583 4134 25 50 75 100

% of total prefixes

Page 35

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SLIDE 36

February, 2007

Quakes and Routing

Edge Analysis

  • PPT (Prefix, Peer, Time) score for each edge: for

each prefix, for each peer, sum the amount of time the peer saw the prefix routed on the edge during a time interval

  • Caveats:
  • All prefixes have the same weight
  • Cannot distinguish between an edge with a lot of

prefixes seen by only few peers, and an edge with few prefixes seen by a lot of peers

Page 36

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SLIDE 37

February, 2007

Quakes and Routing

Edge Analysis (cont'd)

  • For each edge, generate time series with range

25 Dec 2006 to 15 Jan 2007 and 8 hours resolution

  • Considered only prefixes from South-East Asia

and the Indian subcontinent

  • Filter out edges seen by less than 20 peers
  • Evaluate the time series using the 2-day median

difference between end and beginning

Page 37

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SLIDE 38

February, 2007

Quakes and Routing

Top 10 Edge Winners

Page 38

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SLIDE 39

February, 2007

Quakes and Routing

Top 10 Edge Losers

Page 39

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SLIDE 40

February, 2007

Quakes and Routing

Winning Edges

3561_4134 701_9498 15412_18101 3561_1239 4637_4761 15412_9304 4755_9583 7018_4755 701_4761 3356_1239 2914_4657 6762_24077 3356_701 3561_4755 6762_4651 1273_4651 3320_9498 6762_7473 1273_7473 1239_9498 500,000 1,000,000 1,500,000 2,000,000 2,500,000 3,000,000 3,500,000

Top 20 Winners

AS Edges PPT Score / 100,000

Page 40

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SLIDE 41

February, 2007

Quakes and Routing

Losing Edges

7473_9498 3561_7473 3356_7473 6453_4651 1239_4134 3491_4761 3320_9929 7018_9583 7473_4761 7018_4761 3549_7473 9930_ORIGIN 2914_4755 1299_7018 3257_3561 1239_9929 1239_4637 1239_4657 3356_4837 22822_7473

  • 7,000,000
  • 6,000,000
  • 5,000,000
  • 4,000,000
  • 3,000,000
  • 2,000,000
  • 1,000,000

Top 20 Losers

AS Edges PPT Score / 100,000

Page 41

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SLIDE 42

February, 2007

Quakes and Routing

Regional Stories

  • AS7473 Singapore Telecom (SG)
  • AS4134 China Telecom (CN)
  • AS9498 Bharti BT Internet (IN)
  • AS4761 INDOSAT (ID)
  • AS4651 Communication Authority of Thailand (TH)
  • AS24077 TMHK Global Transit (HK)

Page 42

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SLIDE 43

February, 2007

Quakes and Routing

Singapore Telecom (AS7473)

Page 43

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SLIDE 44

February, 2007

Quakes and Routing

China Telecom (AS4134)

Page 44

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SLIDE 45

February, 2007

Quakes and Routing

Bharti BT Internet (AS9498)

Page 45

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SLIDE 46

February, 2007

Quakes and Routing

INDOSAT (AS4761)

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SLIDE 47

February, 2007

Quakes and Routing

Communication Authority of Thailand (AS4651)

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SLIDE 48

February, 2007

Quakes and Routing

TMHK Global Transit (AS24077)

Page 48

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SLIDE 49

February, 2007

Quakes and Routing

Global Stories

  • AS1239 Sprint
  • AS3561 Savvis
  • AS2914 NTT/Verio
  • AS6762 Telecom Italia
  • AS1273 Cable & Wireless

Page 49

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SLIDE 50

February, 2007

Quakes and Routing

Sprint (AS1239)

Page 50

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SLIDE 51

February, 2007

Quakes and Routing

Savvis (AS3561)

Page 51

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SLIDE 52

February, 2007

Quakes and Routing

NTT/Verio (AS2914)

Page 52

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SLIDE 53

February, 2007

Quakes and Routing

Telecom Italia (AS6762) – Winner

Page 53

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SLIDE 54

February, 2007

Quakes and Routing

Cable & Wireless (AS1273) – Winner

Page 54

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SLIDE 55

February, 2007

Quakes and Routing

Interesting Stories During Quake

  • France Telecom (AS5511) provided temporary

transit to Bharti (AS9498) from Dec 27 to Jan 5

  • Indonesian routes move to INDOSAT (AS4761,

AS4795) with transit mostly from DTAG (AS3320)

  • China Netcom (AS9929) uses temporarily Sprint

(AS1239) and DTAG (AS3320) as transits then drops them in favour of UUNet (AS701) and Savvis (AS3561)

  • China Telecom (AS4134) routes move temporarily

from Savvis to Sprint on Dec. 27

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SLIDE 56

February, 2007

Quakes and Routing

Interesting Stories After Quake

  • Telecom Italia (AS6762) and Cable & Wireless

(AS1273) are big winners adding Singapore Telecom (AS7473) and the Communication Authority of Thailand (AS4651) as customers

  • Sprint (AS1239) gets to China Telecom (AS4134)

through HiNet (AS9680) and Chunghwa Telecom (AS3462), i.e., 1239 9680 3462 4134

Page 56

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SLIDE 57

February, 2007

Quakes and Routing

Conclusions

  • Quake illustrates fragility of the global Internet
  • “Local” events can have broad impact
  • Physical failures can be difficult to remedy
  • Asia is particularly vulnerable
  • Impact will be felt long after the repairs are

complete

  • New business relationships
  • New cable systems
  • Renewed interest in redundancy

Page 57

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SLIDE 58

Thank You

Todd Underwood todd@renesys.com Alin Popescu alin@renesys.com Earl Zmijewski earl@renesys.com

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