Autonomous Systems (AS) Introduction and Topology Bradley Huﬀaker CAIDA SDSC/UCSD

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1 Autonomous Systms (AS) Introduction and Topology Bradly Huﬀakr CAIDA SDSC/UCSD WIND March 20

2 ovrviw ovrviw introduction datasts - paths, locations, organizations, rlationships, classifications opn qustions summary 2

3 Intrnt of layrs ovrviw Intrnt maps ar oftn groupd into four lvls. AS 0 Autonomous Systms (AS) ar numbrs usd to rout groups of IP addrsss. l v AS l Points of Prsnc (PoP), locations whr ISP stor thir routrs. l v l P o P Routrs, machins that rout th traffic, intrconnct via IP addrsss. l v rl t rou IP addrsss that connct dvics on to th Intrnt. l v IP l

4 Focus on AS Autonomous Systms (AS) ar numbrs usd to rout groups of IP addrsss. AS 0 l v AS l l v l P o P W will focus on th AS lvl. l v rl t rou l v IP l 4 ovrviw

5 what is an AS? ovrviw An AS can roughly b thought of as a singl organization. Som companis us multipl ASs. AS topology (obsrvd January 20) 5,000+ ASs - organization location - country of rgistration 48,000+ AS links - businss rlationship UCSD 5 Intrnt

Collcting AS paths (BGP) paths:datasts Routr graph 9.0.. 0.0.2. 2 5 4 0.0..5 5.5..28 0.0.. Routs ar announcd by routrs and forwardd toward th collctor.

6 Collcting AS paths (BGP) paths:datasts Routr graph Routs ar announcd by routrs and forwardd toward th collctor. So th last AS, th origin AS, owns (first announcs) th prfix graph discovry from paths, not nods BGP Collctor AS path prfix rout rout 2 rout rout / / / /24 4 origin AS 2 4 5

7 BGP Collctors (raw) paths:datasts Collcting and sharing global routing [Bordr Gatway Protocol (BGP)] data: Univrsity of Orgon, Rout Viws Projct - RIPE NCC (Rgional Intrnt Rgistry for Europ/Middl East) - BGP dump origin AS TABLE_DUMP B / TABLE_DUMP B / TABLE_DUMP B / sourc IP sourc AS prfix AS path

8 AS path (fil) paths:datasts # sourc:topology BGP routviws wid # sourc:topology BGP routviws wid paths.bz2 Th top of th fil lists th sourcs usd to gnrat th fil. # sourc:<typ> <sourc> <dat> <organization> <srvr> Th actual AS path. <sourc> <hop0> <hop>. <dstination> Th sourc AS is whr th path was obsrvd. 8 Your viw of th topology is limitd by th numbr of sourcs and origin ASs. Dpnding on what you ar doing with th data, it oftn hlps to filtr paths to only sourcs that hav all or almost all origin AS.

9 AS dgr typs paths:datasts W hav found that transit dgr is a bttr mtric for capturing th importanc of an AS, sinc it ncods som of th information in th obsrvd paths. monitors undirctd paths 5 M M M M dgrs AS global out transit global dgr out dgr triplts dirctd paths transit dgr 4

10 AS golocation locations:datasts Golocation idntification of ral-world gographic location of Intrnt idntifirs Digital Envoy s Ntacuity commrcial golocation srvr MaxMind GoLit is a fr srvic Ntacuity gographic dump usa ca la jolla usa ca tustin usa ca los angls usa il chicago IP first IP last country stat city latitud longitud 0

siz i golocation blocks origin AS prfix IP block longitud wightd avrag longitud 2 5.5..0/24 5.5..0-5.5..255-0 -0 0.

11 golocation to longitud locations:datasts An AS s longitud quals th wightd avrag of th longituds assignd by Ntacuity to th addrsss it announcs. blocki.coordinats * blocki.siz i blocki.siz i golocation blocks origin AS prfix IP block longitud wightd avrag longitud / / / /

12 AS cntroid (fil) locations:datasts opn qustion #format:as continnt country rgion city lat long total-prfixs as2loc.txt latitud longitud continnt, country, stat, city mpty in this fil AS numbr numbr of prfixs announcd by AS 2

13 AS organization (fil) organizations:datasts opn qustion org-id organization nam as-org2info.txt # format:org_id changd org_nam country sourc 5LINX-ARIN Globalinx US ARIN # format:aut changd aut_nam org_id sourc LINX-ASN 5LINX-ARIN ARIN AS numbr org-id This fil contains both organization and ASs. Th typ changs at vry lin that starts with # format:<typ>. Connct btwn ntris with org-id. In this xampl th AS 49 blongs to organization Globalinx.

14 AS rlationships providr you pay thm to transit your traffic (XO pays AT&T) pr unpaid xchang of traffic (btwn XO and Googl) customr thy pay you to transit thir traffic (UCSD pays XO) organizations:datasts providr $$ pr $$ $$ customr!"#$ 4

15 AS hirarchy rlationships:datasts ASs can b organizd into a hirarchical structur basd on th typ of businss rlationships thy form btwn thmslvs $$ customr providr customr pays providr for transit $$ pr pr prs do not pay to accpt ach othr s traffic 5

16 AS hirarchy rlationships:datasts ASs at th top of th hirarchy ar call Tir-. Togthr thy form th backbon of th Intrnt

17 AS rlationship (fil) rlationships:datasts infrrd Tir ASs as-rl.txt.bz2 Intrnt Xchang Points # infrrd cliqu: # IXP ASs: AS0 AS rlationship typ - AS0 is a providr of AS AS0 AS 0 AS0 and AS ar prs AS0 AS AS0 is a customr of AS AS0 AS

18 AS customr con rlationships:datasts An AS s customr con contains th st of ASs w obsrv th AS announc to its prs or providrs. It is important that this is mor constraind than, but similar to, th st of ASs it can rach through its customrs. AS siz A B D D A C C A B E B Customr Cons F G G H I H 8

19 AS customr con (fil) rlationships:datasts opn qustion ppdc-ass.txt.bz2 AS customr con mmbrs AS siz mmbrs

20 20 AS classification (fil) ASs ar oftn dividd into Transit, Contnt, or Accss dpnding on th typ of companis that oprat thm. Largr organizations can combin all thr typs. - Transit ASs, such as AT&T, form th backbon of th Intrnt carrying traffic btwn ASs. - Contnt ASs, such as Ntflix, provid th vidos, wbpags, and othr contnt. - Accss ASs, such as UCSD or Tim Warnr Cabl, ar usd by smallr organizations to gt accss to th Intrnt. # nam: as2typ #../as-graph-20409/bin/typ-convrt-amogh.pl # typs:accss Contnt Transit/Accss Transit/Accss CAIDA_class 2 Transit/Accss CAIDA_class typ AS numbr as2classification.txt.bz infrnc mthod Googl Contnt classification:datasts opn qustion UCSD Accss Transit Lvl 5

21 incomplt topology opn qustions Givn that BGP only forwards th bst path, an AS graph gnratd xclusivly from limitd numbr of BGP monitors will b incomplt. invisibl from M visibl from M M How incomplt is th topology? graphs links nods c/p pr total total BGP-drivd 9,59 8,852,9 4, tracrout-drivd 0,, 2,42 IX-drivd 0 24,80 24,80,555 combind 9,59 25,2 48,85 4,20 Can w infr th missing topology from what is visibl? AS Topology Dc. 205 (visibility) Givn a st of limitd rsourc monitors, can w crat targtd masurmnts that will find th missing componnts? 2

22 path prdiction opn qustions Du to policy constraints, simpl shortst paths algorithms do not work for th AS topology. paths must follow paid transit valid B is paid by A B is paid by C invalid B C B A B A A C C A A C C B C B A B B is paid by A and C B is not paid by A or C currnt algorithms ar btwn 0% and 80% accurat. asymmtric paths ar common hot potato routing backup packs ar hiddn 22

23 IP to Routr to PoP to AS opn qustions AS 0 AS vl l AS l v l P Po vl l r t rou vl l P I 2 mapping btwn intrfacs and routrs (alias rsolution) mapping btwn routrs and PoPs (golocation) mapping btwn PoPs to AS (routr ownrship)

24 datasts summary as_intro_topology_wind/ paths.txt.bz AS paths slid as2loc.bz AS location slid as-org2info.txt.bz rgistration country and organization information slid as-rl.txt.bz typs of businss rlationships btwn pairs of ASs slid ppdc-ass.bz th st of ASs that ar customrs, slid 9 or customr s customrs of an AS as2classification.txt.bz an AS s typ of businss 24 slid 20

25 summary Qustions? Intrnships: 25

bonus AS placmnt 2 555 24 20225 99 9900 99 22

22 09 04 422 52 4 498 42 480 2922 295 9005

49504 220 290 44 489 9509 5824 500 455 4524

44842 020 0 9828 99528 992 49902 5k 25 4k 528

4 4k 298 2k 250 k 45 k 2092 k 55 k 54 k 80 k

992 550 842 548 59 5 0844 45 49 2 92 20 258 0

95 2 22 292 2 249 92 2 88 992 22 8 0 85 4 828

9 2052 9 2 2 299 4 25 4 2 largr smallr con

uppr right: country flag nod vrtical position

width customr con siz of nighbor link color

26 bonus AS placmnt k 425 k 29 k 52 k k 25 4k 528 4k 400 k 2980 k 525 2k 848 k k k 4 4k 298 2k 250 k 45 k 2092 k 55 k 54 k 80 k 2859 k largr smallr con siz nod labl cntr: AS numbr uppr lft: rank uppr right: country flag nod vrtical position customr con siz nod siz customr con siz link width customr con siz of nighbor link color rlationship typ country flag AS numbr rank

27 AS cor singl AS AS 84 typ num.ass num.links CUSTOMER 2 2 PEER PROVIDER 4 4 Asia bonus nod location and siz st by customr con siz Ocania cntr markd for rfrnc nod and link color st by rlationship to slctd AS Europ Africa slctd AS siz is fixd rgardlss of dgr. draw ordr: customrs, prs, and providrs 84 2 North Amrica South Amrica

28 displacmnt location anycast dlhi k-apni nod numbr of clints (siz) bonus nap k-apnic tokyo dlhi k-dnic k-mix k-apni c wdg numbr of clints (color) avrag distanc to clints (siz) displacmnt map Distanc from clint s cntriod and DNS srvr s gographic location. ams-ix linx nap dlhi linx k-ficix tokyo k-mix location Numbr of map DNS clints in a givn dirction and avrag distanc in that dirction. ams-ix k-dnic k-isnic k-crn k-mix k-grnt k-qtl 28 2

29 Gographic sortd bars bonus 00 F: San Francisco (US) F: Auckland (NZ) F: Nw York (US) F: Brisban (AU) * global instanc F: Santiago (CL) F: Tl Aviv (IL) K: Tokyo (JP) F: Sao Paulo (BR) F:Johannsburg(SA) K: Rykjavik (IS) K: Hlsinki (FI) % Instancs sortd by th numbr of rqusts pr scond. Ocania Asia Africa Europ S. Amr N. Amr 29 0 N.Amr S.Amr Europ Africa Asia Ocania sfo2* pao* nap* linx* ams ix* dlhi* tokyo* lax* ord* iad* jfk*

30 usd addrss spac ARIN LACNIC 0 RIPE NCC AfriNIC APNIC bonus

31 Cod rd bonus

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