Univ. of TehranAdv. topics in Computer Network 1Advanced topicsAdvanced topics ininComputer Computer NetworksNetworksUniversity of TehranDept. of EE and Computer EngineeringBy:Dr. Nasser Yadani!ecture "# AT$# an overviewUniv. of TehranAdv. topics in Computer Network "OutlineOutlineWhy ATMATM overviewATM standardUniv. of TehranAdv. topics in Computer Network %Why ATM?Problems with IP?Best effort, lack of reliabilityTP on to! of IPBein" stateless#o! to ho! or !oint to !oint$%ack of &o'$#ow im!ortant is &o'? It is essential in some a!!lications includin"(oIP(ideo on demand$Teleconferencin"$Univ. of TehranAdv. topics in Computer Network &'u!!ortin" &o' in IP&o' !arameterBounded delay and )itter$Min rateIP should identify flow and kee! state in nodes$ontradictory to ori"inal desi"n "oal, fle*ibility and scalability$an we have both? We try$This is the main challen"e of Internet$Univ. of TehranAdv. topics in Computer Network 'ATM overviewATM + Asynchronous Transfer Mode$ATM + ,ata -etwork . Phone -etworkombination of Internet method of communication /!acket switchin"0 and !hone com!anies1 method /circuit switchin"0Asynchronous2 The way bandwidth is allocated$ The time slot is not allocated by tem!oral !osition like 'ynchronous transfer mode, 'TM, /circuit switch0$Transfer mode+ Multi!le*in" and switchin"$Univ. of TehranAdv. topics in Computer Network (ATM overview /cont0onnection oriented2 -eed si"nalin" like circuit switch$3stablish connection$Tear down connection$reate a virtual connection or circuit, then order is !reserved in carryin" data$Problems?Overhead for connection and tearin" down$%oosin" connectivity in case of failure in nodes$Univ. of TehranAdv. topics in Computer Network )ATM vs$ 'TM'TM or T,MPeak rate allocation4ast and sim!le lo"ic$-ot "ood for bursty traffic like data$ATM2 uses statistical multi!le*in"$5ivin" bandwidth for label$#as to !rocess cells $on"estion is !ossible$(ariable cell delay /&ueuin"0$But, network controls routin", errors, flow, co!yin" and !riorities$Overcome to con"estion and delayis fundamental to ATM$Univ. of TehranAdv. topics in Computer Network *ATM vs$ Phone -etworkurrent !hone networks are synchronous /!eriodic0$ 'TM ATM + Asynchronous Transfer ModePhone networks use circuit switchin"$ATM networks use 6Packet7 'witchin" In !hone networks, all rates are multi!le of 8 kb!s$ With ATM service, you can "et any rate$ 9ou can vary your rate with time$With current !hone networks, all hi"h s!eed circuits are manually setu!$ ATM allows dialin" any s!eed$Univ. of TehranAdv. topics in Computer Network +Interfaces:ser to -etwork Interface /:-I0;Public :-I, Private :-I-etwork to -ode Interface /--I0;Private --I /P2--I0Public --I + Inter2'witchin" 'ystem Interface /I''I0Intra2%ATA I''I /