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On the Correlation of Geographic and Network Proximity at Internet Edges and its Implications for Mobile Unicast and Multicast Routing PDF

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On the Correlation of Geographi and Network Proximity at Internet∗ Edges and its Impli ations for Mobile Uni ast and Multi ast Routing. † Thomas C. S hmidt Matthias Wählis h Ying Zhang t.s hmidtieee.org waehlis hieee.org zhang.yingweb.de 7 HAW Hamburg, Dep. Informatik, Berliner Tor 7, D(cid:21)20099 Hamburg, Germany 0 0 2 n a Abstra t 1. Introdu tion J 0 Signi(cid:28) ant e(cid:27)ort has been invested re ently to a - 2 elerate handover operations in a next generation mo- Mobile environments, devi es and appli ations are one of the major driving for es for te hnologi al de- bile Internet. Corresponding works for developing e(cid:30)- ] velopment today, while deployment is still dominated I ientmobilemulti astmanagementareemergent. Both N by non(cid:21)IP applian es. However, the roadmaps of on- problems simultaneously expose routing omplexity be- s. tweensubsequentpointsofatta hmentasa hara teris- vergedservi esfor Next Generation Networks(NGNs) [16℄ on the one hand, e(cid:30) ient mobility management c ti parameter for handover performan e in a ess net- [ within the next generation Internet [5℄ on the other, works. leadexpe tationstotheInternetlayerastheprevalent 1 As ontinuous mobility handovers ne essarily o ur tie for mobile a ess te hnologies and servi es. v between a ess routers lo ated in geographi vi inity, 0 Seamless support for Voi e over IP (VoIP) and this paper investigates on the hypothesis that geograph- 3 related real(cid:21)time ommuni ation must be onsidered i ally adja ent edge networks attain a redu ed network 1 riti al for deployment su ess into the mobile world. 1 distan es as ompared to arbitrary Internet nodes. We Thereforesigni(cid:28) ante(cid:27)ortis ontinuouslytakeninthe 0 therefore evaluate and analyze edge distan e distribu- 7 tionsinvariousregionsfor lusteredIPrangeson their IETF to develop and improve proto ols for seamless 0 mobility handovers, FMIPv6 [6℄ and HMIPv6 [14℄ be- geographi lo ation su h as a ity. We use tra eroute / ing the most prominent examples. The IP layer in- s to olle t pa ket forwarding path and round-trip-time c trodu ess alablemulti astassupplementaryfun tion, of ea h intermediate node to s an-wise derive an upper : v bound of the node distan es. Results of di(cid:27)erent s an- whi h will be of parti ular importan e to multimedia i group onferen es in mobile environments of limited X ning origins are ompared to obtain the best estima- apa ities. Seamless mobility extensions to IP(cid:21)layer tion of network distan e of ea h pair. Our results are r a ompared with orresponding analysis of CAIDA Skit- multi ast are likewise under preparation [11℄. ter data, overall leading to fairly stable, reprodu ible Mobile IPv6 inherits a strong topology dependen e edgedistan edistributions. Asa(cid:28)rst on lusiononex- through its binding update pro edures with the Home pe ted impa t on handover performan e measures, our Agent (HA) and the Correspondent Node (CN). Han- results indi ate a general optimum for handover anti - dover a eleration s hemes attempt to over ome this ipation time in 802.11 networks of 25 ms. obsta le by relo ating immediate transfer negotiations to the vi inity of the mobile node, i.e., to a ess net- works at the Internet edges. In previous analysis [9℄ it ould be shown that the a tually attained handover Keywords: Internet S anning, Measurement, Edge performan e largely depends on the relative network Distan e Distribution, Mobile Handover Performan e, topology of a ess omponents, when measured in an Mobile Multi ast appropriate delay metri su h as round trip time. A - ∗ This work is supported by the German Bundesministerium essrouterdistan e anbe onsideredasthe hara ter- für Bildung und Fors hung within the Proje t Movie ast. The isti omplexity parameter in fast or hierar hi al mo- aut†horsthankCAIDAformakingSkitter datasetsavailable. bile IPv6. Theauthorisalsowithlink(cid:21)lab,HönowerStr. 35,D(cid:21)10318 Berlin,Germany. Similar observations hold for mobile multi ast. Source: 141.22.64.9 While multi ast listeners may rely on handover oper- ations derived from uni ast proto ols, mobile multi- astsour esneedto reshapedistributiontrees. Due to HHoopp 11:: 114411..2222..6644..11 theself(cid:21)similarnatureofshortestpathtrees,alteration requirements of multi ast forwarding states are mini- HHoopp 22:: 114411..2222..44..112211 mallybound by a hara teristi fun tion of sour e dis- pla ement. As shownin[10℄ the routing ostofmobile HHoopp 33:: 118888..11..4477..5577 multi ast sour e management in SPT-based proto ols is dire tly dominated by the topologi al hop distan e HHoopp 44:: 118888..11..1188..110099 attained between designated routers at the previous and next point of atta hment. HHoopp 55:: 118888..11..1188..115544 Inthisworkweempiri allyanalyzetheregionaledge distan edistributionsofexemplaryareasinthe urrent HHoopp 66:: 118888..11..8800..4466 HHoopp 66::118811..11..8800..6666 Internet. We perform sele tive s ans and evaluate the TTrraannssiitt ppooiinntt datapooloftheCAIDASkitterproje tandderivemo- HHoopp 77:: 8800..8811..119922..220088 bility performan e spe tra thereof. The paper is orga- HHoopp 88:: 119944..114400..111111..222277 HHoopp 88:: 119944..114400..111133..9955 nized asfollows. We introdu eourevaluationmethod- ologies,dis uss problems, limitations and related work HHoopp 99::221122..6633..4466..8877 in the following se tion. Measurement results are pre- sented and dis ussed in se tion 3. Se tion 4 brie(cid:29)y Host 1: 62.8.134.1 derives onsequen es for hara teristi handover per- Network 1 Host 2: 62.8.129.1 forman e measures of our data. Finally, se tion 5 is Network 2 dedi ated to on lusions and an outlook. Figure 1. Transit Point Discovery withtracer- oute 2. Methodology and Related Work 2.1. Edge Distance Estimates assumption) and from the perspe tive of the sour e. The obje tive of this work is to inquire on the dis- S anexperiments thereforearerepeated from multiple tribution of network distan es between pairs of Inter- origins,eventuallydis overing losertransitpointsand net edge routers lo ated within geographi vi inity. shorterneighboringpaths asdisplayed in (cid:28)gure 2. Re- A ording to the mobility investigations introdu ed sults are then derived as minimal upper bound using above, network distan e measures require metri s of the path via the losest transit point. delayandrouting omplexity,e.g.,roundtriptimeand hop ount. S anning an thus be performed by tra er- Geographi lo ationsofIPaddressrangesneedpro- oute and will pro eed as follows. visioning as external input to the s anning. To hoose Clusters of IP ranges from geographi regions su h forareliablesour eofgeographi informationweevalu- as itiesarepre-sele tedinordertoa ountforlo ality. atedeightdi(cid:27)erentmappingresour esina(cid:28)rststepby Alifehostisdeterminedfromea hrange,su hthatfor sele ting a set of 30 distributed, geographi allyknown ea h pair of hosts the network distan e of their orre- IP ranges. The ommer ial produ t GeoIP [7℄ thereby sponding a ess routers an be evaluated as a sample was the only resour e to admit negligible errors. In a probe. Theappropriatemethodtodeterminearouting se ond, automated testing we ompared data of larger pathbetweentwoInternethostsfromaremotelo ation samples with whois queries and found a oin iden e isgivenbyloosesour erouting. Sin esour eroutingis rate of about 80 %. This result we onsidered reason- mainly unsupported throughout the Internet, we pro- able, as whois data ommonly provide administrative eed by auxiliary means as shown in (cid:28)gure 1: Both addressespossiblydistin tofphysi alrouterlo ations. routingpathfromtheorigintothehostsunder onsid- It should be mentioned that measurements have erationare evaluated via tra eroute [3℄ and ompared. been undertaken forIPv4 only, even though the initial Thelast ommonhopthenisdeterminedasapotential motivation was derived from mobile IPv6 handovers. transitpoint,givingrisetoanupperbound ofthenet- Due to our limited a essibility of IPv6 ommuni a- workpathbetweenthe targetnodesviathedis overed tion this pro edureis justi(cid:28)ed by the expe tation that transit point. Su h Evaluation is done under the as- quantitatively dominating dual sta k a ess networks sumption of symmetri routing ( f. se tion 2.2 on this will attain identi al topologi al properties. Source 1 The Mer ator proje t [1℄ uses hop-limited probes in Source 2 the same manner as tra eroute, to infer an Internet TTrraannssiitt ppooiinntt 11 map at the route-level. A highly distributed s anning TTrraannssiitt ppooiinntt 12 approa his taken within the DIMES proje t [12℄ with the aim of in reased a ura y and omprehensiveness. Aside from many others, Jani and Van Mieghem [4℄ re ently performed tra eroute s ans to investigate the node degree distribution in the Internet and report about ompli a ies similar to our observations. Sin e IP addresses are lo ation-independent, there HHoosstt 11:: 221177..8899..4477..111133 has been mu h work on the problem of orrelating IP NNeettwwoorrkk 11 HHoosstt 22:: 221177..8833..118855..110099 addresses to geographi lo ations. One of the latest NNeettwwoorrkk 22 studieswasdonebySubramanianetal. [15℄. Theysug- gest that 90 % of nodes within 5 ms RTT are lo ated Figure 2. Approximation by Multisource within a radius of 50 km and 90 % of nodes within Scanning 10 ms RTT are lo ated within a radius of 300 km. A CAIDA group [2℄ has studied network onne tivity in the Asia-Pa i(cid:28) region, mainly fo using on network 2.2. Scanning Problems with traceroute laten y and performan e, ountry peering and third partytransit. Theyuseskitter to measuretheforward IP path and round-trip-time to about 2,000 destina- Thewellknowntra erouteutility[3℄sendsoutTTL tions in the Asia-Pa i(cid:28) region from di(cid:27)erent sour es restri tedUDPprobepa ketstoinquireonallforward- and on ludethatgeographi proximityre(cid:29)e tsonlyin ing nodes along a path to a given destination. It thus round trip times, while hop ount is not a representa- leadstoa ompletetopologi alpathve toroftheexam- tive metri therefor. ined route. However, a fair number of nodes through- out the Internet does not reply orre tly to standard tra eroute queries for several reasons. At (cid:28)rst, UDP 3. Regional Edge Distan e Distributions forwarding may be blo ked at some router, in whi h ase tra eroute an be swit hed to use ICMP probes. Inthisse tionwepresenttheresultsforthe itiesof Ifthelatterareblo ked,aswell,probingissu essfully San Fran is o, USA, Berlin and Hamburg, Germany, inhibited. Atse ond,ICMPrepliesaresometimessup- and Shanghai, China, whi h were exemplarily sele ted pressed or manipulated by ISPs, whi h only interferes as geographi target regions. S anning has been per- with our measurements if this happens at or beyond formedfromSeptember to De ember 2006,originating a transit node. The o urren e of routing loops be- from the lo ations of Berlin, Hamburg and Shanghai, yond the transit point will likewise lead to dis arding at the 67th IETF meeting in San Diego and with the the event. The most frequent reason for obtaining in- 1 help of various publi tra eroute fa ilities. Sin e the validdataresultsfromasymmetri routes,dis overable numberofavailableIPrangesvaryfromShanghai(763) by de reasing umulative round trip times. In a gen- up to San Fran is o (8476), subsets of equal sizes are eral attempt Paxson [8℄ analyzed 40,000 end(cid:21)to(cid:21)end sele tedrandomlyforea h ity. Statisti al onvergen e paths and identi(cid:28)ed half of them as asymmetri . As withrespe tto samplesize, but alsofordi(cid:27)erentdates ourexperimental on ern on entratesonedgetopolo- and day times were ompared, and a fair stability of gies, measurements remain una(cid:27)e ted by asymmetries the distributions ould be observed for sample subsets within the ore, leading to signi(cid:28) antly lowereventre- of 500 IP ranges. je tion rates. Altogether the su ess ratio in our mea- We ompare our results with distributions derived surements varies between 45 % and 65 %. fromCAIDAdatare ordedinO tober2006. Host lus- 2.3. Related Work ters for sele ted ities are taken from the CAIDA des- tination list a ording to the GeoIP database. Tra e paths are minimized with respe t to all available 18 Internettopologyhasbeenstudiesforovertenyears. monitor points, whi h are lo ated more densely at the These studies fo us on hara terizing and delineating US West Cost and sparsely in Europe and Asia. Internet topology and performan e. CAIDA [13℄ is a prominent group of pioneers, who re ord and mea- 1Publi tra erouteservi esdidnotprovideICMPprobingand sure Internet data ontinuously for almost ten years. resultantly providedonlylittlesu essrates. Berlin, Germany <x>=9,42273 x=2,99129 Berlin, Germany <x>=12,02614 x=5,67525 0,15 Hamburg, Germany <x>=8,00368 x=2,89005 0,15 Hamburg, Germany <x>=10,94393 x=4,98594 San Francisco, USA <x>=15,55914 x=5,80903 San Francisco, USA <x>=9,49885 x=5,33369 ncies SRhaanndgohma i , C h i n a <<xx>>==1195,,8267888577 xx==75,,7439897265 ncies SRhaanndgohma i , C h i n a <<xx>>==1142,,3542582721 xx==45,,7602908151 e e qu0,10 qu0,10 e e Fr Fr e e v v ati ati el el R R 0,05 0,05 0,00 0,00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Distance [Hops] Distance [Hops] (a) S an Data (b) CAIDAData Figure 3. Hop Count Distributions at Network Edges in Four Cities. < x > and σx represent mean andstandarddeviationofthecorrespondingdistributions. 0,05 0,05 Berlin, Germany <x>=86,29672 x=185,46638 Berlin, Germany <x>=94,14779 x=130,77141 Hamburg, Germany <x>=79,75878 x=175,09762 Hamburg, Germany <x>=73,43109 x=116,76854 0,04 0,04 San Francisco, USA <x>=73,1862 x=68,57574 San Francisco, USA <x>=21,08282 x=43,99535 es Shanghai, China <x>=388,07119 x=341,45648 es Shanghai, China <x>=257,61768 x=252,64217 enci0,03 Random Location <x>=277,49569 x=242,80439 enci0,03 Random <x>=150,74125 x=265,74948 u u q q e e Fr Fr e e ativ0,02 ativ0,02 el el R R 0,01 0,01 0,00 0,00 0 50 100 150 200 250 300 0 50 100 150 200 250 300 RTT [ms] RTT [ms] (a) S anData (b) CAIDAData Figure4.RoundTripTimeDistributionsatNetworkEdges Resulting distributions for hop ounts and round San Fran is o, e.g., in San Jose, whereas signi(cid:28) ant trip times aredisplayed in (cid:28)gures3 and 4respe tively. parts of our distribution was built from s ans at San Anadditional urvederivedforrandomlylo atednodes Diegoorigin. Fromthis argumentit maybe on luded is added to distinguish lo ality orrelations. thatourdatabetterapproximateedgedistributions of the European ities, while CAIDA values re(cid:29)e t those Clearly our hop ount results vary signi(cid:28) antly, of San Fran is o in a better quality. whileCAIDAskitterdataevaluatetofairlysimilardis- tributions. For Berlin and Hamburg we measure lear Hop ounts in Shanghai admit mu h wider distri- peaksataround8hopsandunderestimatethosevalues butions, even though data are mainly re orded from of CAIDA, while we slightly overestimate hop ounts a sour e in Shanghai. S ans originating from Europe for San Fran is o. These di(cid:27)eren es may be explained even show a geographi anti(cid:21) orrelation when om- by monitor point positions. While we had dire t a - pared to the random sample. These results indi ate ess to several networks lo ated in Berlin and Ham- thatregionalroutingtopologiesarenotdenselymeshed burg, skitter data are not available from any monitor in the Chinese ity, su h thatgeographi allyneighbor- point loseto thetwo itiesorevenin Germany. Some ing a ess networks are mainly onne ted via a gen- CAIDA monitor points are lo ated in lose vi inity of eral degree of indire tion. On the ontrary, Berlin 0,25 In total the results seem to indi ate that inter(cid:21)edge Origin Hamburg, Germany routing within a geographi region is frequently per- Origin San Diego, USA 0,20 formed via lo al transits and peering, whi h produ e s network proximity in 'the neighborhood', but remain e nci invisible for a distant monitor. e0,15 u q e Fr e ativ0,10 4. Appli ations to Handover Perfor- el R man e 0,05 The results obtained so far may serve as an empiri- 0,00 al fundament for realisti handover performan e esti- 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 RTT [ms] matesofthenetwork. Amobilenode movingfromone a ess network to another in geographi al neighbor- Figure 5. RTT Distributions Evaluated from hood does imposes tra(cid:30) redire tion, minimally from DifferentOriginsforSanFranciscoNodes its previous to its new atta hment. These operations ause delay and routing osts, whi h for the ase of FMIPv6 [6℄ are given by the uni ast path from previ- ous to next a ess router, and higher, otherwise. and Hamburg results expose a pronoun ed lo ation(cid:21) Basedontheresultsderivedin[9℄wenow animme- to(cid:21)network hop distan e orrelation, whi h somewhat diately al ulate expe ted values of hara teristi han- ontradi ts the on lusions drawn in [2℄. Caida mon- dovermeasures. Forpa ketssentata onstantbitrate itors seem to be too sparsely distributed to at h a of one per 10 ms, the onditional expe tation of pa k- lear, distinguishable view on hop ount laws at Inter- ets lost or bu(cid:27)ered for given inter(cid:21)a ess(cid:21)router delay net edges. was derived for predi tive and rea tive handover pro- Round trip time distributions exhibit similar be- edures ( f. (cid:28)gure 6 of [9℄). Combining these previous havior. Pronoun ed peaks at lose distan es an be results with those shown in (cid:28)gure 4, we arrive at ex- observed for the areas of Berlin and Hamburg, when pe ted periods forpa ketlossasfun tions of handover monitored from the lose vi inity. The e(cid:27)e t of s an- anti ipation times. Results for the di(cid:27)erent regions as ning sour e positioning on RTT results is shown for presented in (cid:28)gure 6 jointly show a pronoun ed uni- San Fran is o data in (cid:28)gure 5. RTT hara teristi s, form minimum at handover anti ipation of 25 ms for though, appear heavier tailed than hop ounts, whi h the ities ofSan Fran is o,Hamburgand Berlin, while supposedly is due to sporadi slow transition links. signi(cid:28) ant optimal values remain absent for Shanghai Tardy transitions are of lesser e(cid:27)e t in the San Fran- and random data. These results re(cid:29)e t the degree of is o region, for whi h again CAIDA measurements lo ality in regional delay distributions. segregate a distribution of higher signi(cid:28) an e. Similar on lusions anbedrawnfor ostsneededto In ontrast, Shanghai data attain merely indi(cid:27)er- reshape shortest path multi ast distribution trees un- entRTTdistributions,whi hareevenlesspronoun ed der sour e mobility. In previous simulation studies we than random samples. Non-negligible weights are sit- derived onditionalexpe tationsformulti astforward- uated beyond the displayed interval, as an be read ing state persisten e at a given hop distan e between from mean and standard deviation values. This may previous and next designated router ( f. (cid:28)gure 3 of be explained from a wide variety of slow transit links 2 [10℄). Resolving onditioningwiththehelpofabovere- present in the Chinese ore networks. CAIDA skit- sults gives rise to an expe ted ratioof multi ast states ter data seem to qualitatively re(cid:29)e t these RTT law persistentunder mobility fortheregionsunder onsid- diversities. San Fran is o values are very pronoun ed, eration. A mobile multi ast sour e feeding a region- whereas Hamburg and Berlin data show an interme- ally distributed group in San Fran is o, Hamburg or diate hara teristi . It should be noted, though, that Berlinwillhavetoexpe tonhandovertheinvalidation thereverseoftheproximityobservationsfrom[15℄does of about 5% of forwardingstates at multi ast routers, not seem to hold: RTT distributions admit wide tails, while10%oftheroutersina omparablehandoversit- when eevenin loserouterdistan esenhan edmutual uation in Shanghai need to establish new states. Cor- delays may be expe ted. respondingly, from 75 % down to 60 % of multi ast 2Anotherpossibleexplanation ouldlieinaredu eda ura y states survive a sour e handover in widely distributed ofMaxMindGeoIP datafortheChineseregion. groups. 130 COM 2000, volume 3, pages 1371(cid:21)1380, Pis ataway, NJ, USA, Mar h 2000. IEEE Press. 120 [2℄ B.Hu(cid:27)aker,M.Fomenkov,D.Moore,E.Nemeth,and 110 k la(cid:27)y. Measurements of the Internet topology in ms]100 the Asia-Pa i(cid:28) Region. In INET 2000 Pro eedings, s [ Yokohama, Japan, June 2000. InternetSo iety. s o L 90 [3℄ V. Ja obson. Tra eroute tool. et ck ftp://ftp.ee.lbl.gov/tra eroute.tar.gz, 1989. Pa 80 [4℄ M. Jani and P.VanMieghem. Onproperties ofmul- 70 Berlin, Germany ti ast routing trees. Int. J. Commun. Syst.,19(1):95(cid:21) Hamburg, Germany San Francisco, USA 114, 2006. 60 Shanghai, China [5℄ D. B. Johnson, C. Perkins, and J. Arkko. Mobility Random 50 Support in IPv6. RFC3775, IETF, June 2004. 0 25 50 75 100 [6℄ R. Koodli. Fast Handovers for Mobile IPv6. RFC Anticipation Time [ms] 4068, IETF, July 2005. Figure 6. Expected Packet Loss in Predic- [7℄ MaxMind LLC. GeoIP. http://www.maxmind. om, tive Handoversas a Functionof Anticipation 2006. [8℄ V. Paxson. End-to-End Routing Behavior in the In- Time(0=ReactiveHandover) ternet. IEEE/ACMTrans.Netw.,5(5):601(cid:21)615, 1997. [9℄ T. C. S hmidt and M. Wählis h. Predi tive ver- sus Rea tive (cid:21) Analysis of Handover Performan e and Its Impli ations on IPv6 and Multi ast Mobil- 5. Con lusions and Outlook ity. Tele ommuni ation Systems, 30(1(cid:21)3):123(cid:21)142, November2005. [10℄ T. C. S hmidtand M. Wählis h. Morphing Distribu- Quality of servi e hara teristi sof the Internet are tionTrees (cid:21) OntheEvolutionof Multi astStatesun- likelytodriveordelaythedeploymentofall(cid:21)IPmobile derMobilityandanAdaptiveRoutingS hemeforMo- devi es. Inspired by mobile IP handover performan e bile SSMSour es. Tele ommuni ation Systems, O to- measures we analyzed routing distan es in geograph- ber 2006. in print,appeared online. i ally bound lusters of the Internet, in whi h users [11℄ T. C. S hmidt and M. Wählis h. Multi ast Mobility areexpe ted to movearoundfreely while ontinuously in MIPv6: Problem Statement. IRTF Internet Draft 'talking'IPin thenearfuture. Tra erouteprobeshave (cid:21) work in progress 01, MobOpts, O tober 2006. been used to derive hop ount and delay distributions [12℄ Y. Shavitt and E. Shir. DIMES: Let the Inter- at Internet edges in San Fran is o, Berlin, Hamburg net Measure Itself. Te hni al Report s.NI/0506099, andShanghai. Comparisonhasbeen drawnto CAIDA arXiv.org, June 2005. [13℄ Skitter Proje t at CAIDA. measurements. Our results seem to indi ate a lear http://www. aida.org/tools/measurement/skitter. signatures of lo ality in both distan e metri s, whi h [14℄ H. Soliman, C. Castellu ia, K. Malki, and L. Bel- annot be segregated from CAIDA measurements due lier. Hierar hi al Mobile IPv6 mobility management to sparsely s attered monitor points. The appli ation (HMIPv6). RFC 4140, IETF, August2005. of these results to al ulating pa ket loss after mobil- [15℄ L. Subramanian,V.Padmanabhan,andR.Katz. Ge- ity handovers indi ates that hara teristi proximity ographi Properties of Internet Routing. In Pro eed- measures in the Internet may give rise to fairly stable ings of the 2002 USENIX Annual Te hni al Confer- anti ipation timers. en e, pages 243(cid:21)259, Berkeley, CA, USA, June 2002. In future work we will re(cid:28)ne our measures by tar- USENIXAsso iation. [16℄ Tele ommuni ations and Internet onverged Servi es geting additional geographi regions and adding Plan- and Proto ols for Advan ed Networking (TISPAN); etLab nodes to our monitors. We intend to in lude NGN Release 1; Release de(cid:28)nition. Te hni al Report DIMES data into our omparison, ontinue to derive 180 001 V1.1.1, ETSI, Mar h 2006. QoS distributions and hara teristi values from re- gional delay distributions to put expe ted handover hara teristi s of a future mobile Internet on (cid:28)rmer grounds. Referen es [1℄ R. Govindan and H. Tangmunarunkit. Heuristi s for internet map dis overy. In Pro eedings IEEE INFO-

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