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Struktura e Internetit : Rrjeti i rrjetave. Opcion : lidh cdo ISP aksesi ne nje ISP global tranziti ? KLientat dhe providerat ISP kane marreveshje biznesi. …. …. …. …. global ISP. access net. access net. access net. access net. access net. access net. access net.
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Struktura e Internetit : Rrjetiirrjetave Opcion: lidhcdo ISP aksesi ne nje ISP global tranziti? KLientatdheprovideratISP kanemarreveshjebiznesi … … … … globalISP access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net … …
Struktura e Internetit : Rrjetiirrjetave Porduhettejenedisa ISP globaleqeteketekonkurence…. … … ISP B ISP A ISP C … … access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net … …
Struktura e Internetit : Rrjetiirrjetave Porduhettejenedisa ISP globaleqeteketekonkurence …. DheketoISP duhettenderlidhen Internet exchange point … … ISP B ISP C ISP A IXP IXP … … access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net peering link … …
Struktura e Internetit : Rrjetiirrjetave … dherrjetarajonalemundteduhenper telidhurrrjetat e aksesit … … ISP B ISP C ISP A IXP IXP … … access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net regional net … …
Struktura e Internetit : Rrjetiirrjetave … dheproviderate pembajtjes (psh., Google, Microsoft, Akamai ) mundtekenerrjetat e vetaqetesjellinsherbimet, permbajtjenpraneperdoruesve … … ISP B ISP B ISP A IXP IXP … … Content provider network access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net access net regional net … …
Struktura e Internetit : Rrjetiirrjetave Ne qender: numerivogelrrjetashtemedha mire telidhura “tier-1 (rreshtii pare)” ISP komerciale(psh., Level 3, Sprint, AT&T, NTT), mbulimkombetar e nderkombetar Rrjetatprovideravetepermbajtjes(psh, Google): rrjetprivatqelidhqendrat e tedhenavetesaj me Internet, shpesh duke tejkaluartier-1, provideratrajonale Tier 1 ISP Tier 1 ISP Google IXP IXP IXP Regional ISP Regional ISP access ISP access ISP access ISP access ISP access ISP access ISP access ISP access ISP Introduction
Tier-1 ISP: psh., Sprint POP: point-of-presence to/from backbone peering … … … … … to/from customers Introduction
Chapter 1: roadmap 1.1 CfareeshteInterneti? 1.2rrjetiskajor sistemetfundore, rrjetat e aksesit, linjat 1.3 rrjetiqendror transmetimi (kycja) me pakete, kycja me qark, struktura e rrjetave 1.4 vonesa, humbje, sjelljane rrjeta 1.5shtresat e protokolleve, modelet e sherbimeve 1.6rrjetatnensulm: siguria 1.7histori Introduction
Si ndodhinhumbjetdhevonesat? Paketatvihen ne rradhe ne buferat e routerave Ritmiipaketave ne arrdhjetejkalon (perkohesisht) kapacitetin e linkuttedaljes Paketatpresintuvijerradha Paketeqepotransmetohet(vonesa) pakete ne rradhe(vonesa) Buferi lire: paketat ne ardhjehumbennesenuk ka buferate lire A B Introduction
Katerburimet e vonesavetepaketave dproc: perpunimi ne nyje Kontrolligabimevetebiteve Percaktonlinkun e daljes zakonisht < msec transmetimi A perhapja B Perpunimi ne nyje rradha dnodal = dproc + dqueue + dtrans + dprop dqueue: vonesaprejrradhes • Koha e pritjes ne linkun e daljes per transmetim • Varetnganiveliibllokimitteruterit Introduction
dtrans and dprop very different Katerburimet e vonesavetepaketave tranmetim A Perhapje propagation B Perpunim ne nyje (Processing) Rradha (queueing) dnodal = dproc + dqueue + dtrans + dprop dprop: vonesa e perhapjes: • d: gjatesia e linkutfizik • s: shpejtesia e perhapjes ne mjedis(~2x108 m/sec) • dprop = d/s dtrans: vonesa e transmetimit: • L: gjatesia e paketes(bits) • R: bandwidth ilinkut(bps) • dtrans= L/R * Check out the Java applet for an interactive animation on trans vs. prop delay Introduction
Analogjia me karvanin Makinat“perhapen” me shpejtesi100 km/hr kontrolli do 12 sec per tesherbyernjemakine (koha e transmetimittenjebiti) makina~bit; karvani ~ paketa Pyetje: Sa kohe do qekarvaniterreshtohetperparakontrollittedyte? Koha per te “shtyre” tegjithekarvaninngakontroli ne autostrade = 12*10 = 120 sec Koha e “perhapjes” se makines se funditngakontrollii pare ne ate tedytin: 100km/(100km/hr)= 1 hr Pergjigje: 62 minutes 100 km 100 km Karvan me 10 makina Kontrolli/ pagesa Kontrolli/ pagesa Introduction
Analogjia me karvanin(me shume) Supozotanimakinat“perhapen” me 1000 km/hr Dhesupozokontrolli do nje min t’isherbejenjemakine Pyetje: A do tearrijnemakinat ne kontrollin e dyteperpara se tegjithemakinattejenesherbyer ne kontrollin e pare? A: Po!Mbas 7 min, makina e pare arrin ne kontrollin e dyte; tremakinajaneakoma ne kontrollin e pare. 100 km 100 km Karvani me 10 makina kontroll itakses kontroll itakses Introduction
R: bandwidth ilinkut (bps) L:gjatesia e paketes (bits) a: ritmimesatariarritjes se paketave Vonesa ne rradhes (e ripare) average queueing delay traffic intensity = La/R • La/R ~ 0: vonesamesatare ne rradhe e vogel • La/R -> 1: vonesamesatare ne rradhe e madhe • La/R > 1: me shume “pune” poarrin qeduhetsherbyer, vonesamesatareinfinit! La/R ~ 0 La/R -> 1 * Check out the Java applet for an interactive animation on queuing and loss Introduction
Vonesatdherruget “reale” teInternetit Si dukenvonesatdhehumbjet “reale” teInternetit? ProgramiTraceroute: jepmatjen e vonesesngaburimi ne router gjaterruges ne Internet fillim-fund deri ne arritje. Per tegjithai: Dergontrepaketaqe do tearrijnecdo router i ne rrugendrejtarritjes router i do tekthejepaketatekderguesi Derguesi mat intervalin e kohes midis transmetimitdhepergjigjes. 3 probes 3 probes 3 probes Introduction
Vonesatdherruget “reale” teInternetit traceroute: gaia.cs.umass.edu to www.eurecom.fr 3 matjetevonesesnga gaia.cs.umass.edu ne cs-gw.cs.umass.edu 1 cs-gw (128.119.240.254) 1 ms 1 ms 2 ms 2 border1-rt-fa5-1-0.gw.umass.edu (128.119.3.145) 1 ms 1 ms 2 ms 3 cht-vbns.gw.umass.edu (128.119.3.130) 6 ms 5 ms 5 ms 4 jn1-at1-0-0-19.wor.vbns.net (204.147.132.129) 16 ms 11 ms 13 ms 5 jn1-so7-0-0-0.wae.vbns.net (204.147.136.136) 21 ms 18 ms 18 ms 6 abilene-vbns.abilene.ucaid.edu (198.32.11.9) 22 ms 18 ms 22 ms 7 nycm-wash.abilene.ucaid.edu (198.32.8.46) 22 ms 22 ms 22 ms 8 62.40.103.253 (62.40.103.253) 104 ms 109 ms 106 ms 9 de2-1.de1.de.geant.net (62.40.96.129) 109 ms 102 ms 104 ms 10 de.fr1.fr.geant.net (62.40.96.50) 113 ms 121 ms 114 ms 11 renater-gw.fr1.fr.geant.net (62.40.103.54) 112 ms 114 ms 112 ms 12 nio-n2.cssi.renater.fr (193.51.206.13) 111 ms 114 ms 116 ms 13 nice.cssi.renater.fr (195.220.98.102) 123 ms 125 ms 124 ms 14 r3t2-nice.cssi.renater.fr (195.220.98.110) 126 ms 126 ms 124 ms 15 eurecom-valbonne.r3t2.ft.net (193.48.50.54) 135 ms 128 ms 133 ms 16 194.214.211.25 (194.214.211.25) 126 ms 128 ms 126 ms 17 * * * 18 * * * 19 fantasia.eurecom.fr (193.55.113.142) 132 ms 128 ms 136ms trans-oceanic link * Do tethotenuk ka pergjigje(probe e humbur, router nukpergjigjet) * Do some traceroutes from exotic countries at www.traceroute.org Introduction
Humbja e paketave rradha(ose buffer) e linkutparaardhes ne buffer ka kapacitettefundem Paketatqearrijnekurrradhaeshte plot hidhen (osehumben) Paketat e humburamundteritransmetohennganyjaparaardhese, ngaburimi ne sistem, osetemosritransmetohet buffer (zona e pritjes) Paketaqepotransmetohet A B paketaqepoarrin ne nje buffer plot eshtehumbur * Check out the Java applet for an interactive animation on queuing and loss Introduction
Throughput - sjellja throughput:ritmi (bite/ne njesine e kohes) me tecilenbitettransferohen midis derguesit /marresit E castit:ritmi ne nje cast tekohes mesatare:ritmi ne njeperiudhetegjate tub qembanleng me ritemRsbits/sec) tub qembanleng me ritemRcbits/sec) serveridergon bite (ngjashmeri me leng) ne tub link capacity Rsbits/sec server, with file of F bits to send to client link capacity Rcbits/sec Introduction
Throughput (vazhdim) Rs < RcSa eshtethroughputimesatarfillim-mbarim? Rsbits/sec Rcbits/sec Rcbits/sec bottleneck link (linku me ingushte) Linku ne rrugenfillim-fund qekufizonthroughputinfillim-fund Rsbits/sec • Rs > RcSa eshtethroughputimesatarfillim-mbarim? Introduction
Throughput: Skenari ne Internet throughput: min per lidhjenfillim-fund (Rc,Rs,R/10) Ne praktike: Rcose Rseshtezakonisht bottleneck Rs Rs Rs R Rc Rc Rc 10 lidhje (ne menyretedrejte) ndajnelinkunbottleneck Rbits/sec Introduction
Chapter 1: roadmap 1.1 what is the Internet? 1.2 network edge end systems, access networks, links 1.3 network core packet switching, circuit switching, network structure 1.4 delay, loss, throughput in networks 1.5 Shtresat e protokollit, Modelet e sherbimit 1.6 networks under attack: security 1.7 history Introduction
“Shtresat” e Protokollit Rrjetatjanekomplekse, Me shume“pjese”: hoste routera linke me mjedisetendryshme zbatime protokolle hardware, software Pyetje: A ka ndonjeshprese per struktureteorganizuarterrjetave? …. Ose se pakudiskutimiynembirrjetat? Introduction
Organizimiiudhetimitajror Njeserihapash bileta(complain) bagazhe(claim) porta (dalje) Ulje e aeroplanit airplane routing bileta (blerje) bagzhe (kontrol) porta (hyrje) ngritja e aeroplanit airplane routing airplane routing Introduction
Shtresezimiifunksionevetefluturimit lshtresa:cdoshtreseimplementonnjesherbim Nepermjetveprimevetetijbrendashtreses Mbeshtetet ne sherbimet e dhenangashtresa e meposhteme ticket ticket (purchase) baggage (check) gates (load) runway (takeoff) airplane routing ticket (complain) baggage (claim gates (unload) runway (land) airplane routing baggage gate airplane routing airplane routing takeoff/landing airplane routing Airporti I nisjes Qendrat e ndermjetmetekonrollittetrafikutajror Airport iarritjes Introduction
Pseshtresezim? Duke u marre me sistemekomplekse: Struktureeksplicitelejonidentifikimin, marrdhenietndermjetpjesevetesistemitkompleks reference model referenceishtesezuar per diskutim Modularizimilehtesonmirembajtjen, updating e sistemeve Ndryshimiiimplementimittesherbimitteeshtetransparent per pjesentjetertesistemit P.sh, ndryshimiiprocedurave ne portanukndikon ne pjesentjetertesistemit Shtresezimiikonsideruaridemshem? Introduction
Internet protocol stack zbatim:zbatime me mbeshtetjengarrjeti FTP, SMTP, HTTP transport:trnsmetimtedhenashproces-proces TCP, UDP rrjet: routing idatagramevengaburimi ne destinacion IP, routing protocols link:transferimtedhenash midis elementekomshinj ne rrjet Ethernet, 802.111 (WiFi), PPP fizik: bits “ne tel” zbatim transport rrjet link fizik Introduction
ISO/OSI modeliireferimit prezantim:lejonzbatimetteinterpretojnekuptimin e tedhenave, p.sh., enkriptimi, kompresimi, konvencionespecifiketemakines sesion:sinkronizim, kontroll, recovery of data exchange Internet stack “nuk I ka”ketoshtresa! Ketosherbime, nesekerkohen,duhetteimplementohennezbatime Jane tenevojshme? zbatim prezantim sesion transport rrjet link fizik Introduction
Enkapsulimi network link physical link physical M M M Ht M Hn Hn Hn Hn Ht Ht Ht Ht M M M M Ht Hn Ht Hl Hl Hl Hn Hn Hn Ht Ht Ht M M M source message application transport network link physical segment datagram frame switch destination application transport network link physical router Introduction
Chapter 1: roadmap 1.1 what is the Internet? 1.2 network edge end systems, access networks, links 1.3 network core packet switching, circuit switching, network structure 1.4 delay, loss, throughput in networks 1.5 protocol layers, service models 1.6 networks under attack: security 1.7 history Introduction
Siguria e Rrjetave Fusha e sigurise se rrjetave: Si mundentekeqinjtetesulmojnerrjetat e kompjuterave Si mundt’imbrojmerrjetatngasulmet Si teprojektohenarkitekturaqejaneimunendajsulmeve Internetinukeshteprojektuarfillimisht me (shume) siguri ne mendje Vizioniorigjinal:“njegrupperdoruesishqebesojnenjeri-tjetrintelidhur me njerrjet transparent” Projektuesit e protokollevete Internet duke u pershtaturkushteve Konsideratasigurie ne tegjithashtresat! Introduction
Te keqinjte: fut malware ne hostenepermjetInternetit malware mundtefutet ne host nga: virus: infektimqevetereplikohet duke marre/ekzekutuarobjekte (psh., e-mail attachment) krimb: infektimqevetereplikohet duke marre ne menyrepasiveobjekteqeveteekzekutohen spyware malwaremundteregjistroje keystrokes, web site tevizituara, upload info tekfaqja e mbledhjes Hostet e infektuaramundtefuten ne botnet,teperdorura per spam. SulmetDDoS Introduction
Denial of Service (DoS) (Mohimsherbimi):sulmuesitbejneresurset (server, bandwidth) tepamunduara per trafikunligjitim duke mbingarkuar me trafikterreme target Te keqinjte: sulmservareve, infrastruktures se rrjetit 1.zgjidhtarget 2.Thyerje ne hostet ne rrjet 3.Dergopaketa ne target ngahostet e komprementuara Introduction
Te keqinjtemundpergjojnepaketat paket“sniffing”: broadcast media (shared ethernet, wireless) promiscuous network interface reads/records all packets (e.g., including passwords!) passing by src:B dest:A payload C A B • wireshark software used for end-of-chapter labs is a (free) packet-sniffer Introduction
Te keqinjtemundperdorinadresaterreme IP spoofing:dergopaketa me adreseburimiterreme src:B dest:A payload C A B … lots more on security (throughout, Chapter 8) Introduction
Introduction: summary covered a “ton” of material! Internet overview what’s a protocol? network edge, core, access network packet-switching versus circuit-switching Internet structure performance: loss, delay, throughput layering, service models security history you now have: context, overview, “feel” of networking more depth, detail to follow! Introduction