Computer Networks ECS 152B
Popular in Course
Popular in Engineering Computer Science
This 22 page Class Notes was uploaded by Ashleigh Dare on Tuesday September 8, 2015. The Class Notes belongs to ECS 152B at University of California - Davis taught by Staff in Fall. Since its upload, it has received 61 views. For similar materials see /class/187799/ecs-152b-university-of-california-davis in Engineering Computer Science at University of California - Davis.
Reviews for Computer Networks
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/08/15
E65 1523 Computer Network Lecture 16 Demef Aksoy EB 1528 Computer Networks 1 Mul ricasfing Packe l39s delivered 1390 a subset of network nodes Many applica ons RealTime media delivery Sof rwar e upgrades EB 1528 Computer Networks Mul ricas r one sender To many r ceivers m ul ricas r sending To mul riple receivers wi rh ingle Transmi r opera rion analogy one Teacher To many s ruden rs Mul l39icasf via unicasf source sends N unicas r da ragrams one addressed To each of N receivers lt mulficasf receiver red nof a mulficasf receiver red roufers 7 forward unicasf dafagrams EB 1528 Computer Networks 3 Mul ricas r one sender To many receivers m Ne l39work mul l39icasf Rou rer ac rively par ricipa re in mul ricas r making copies of packe rs as needed and forwarding Towards mul ricas r receivers roufzrs red duplicafz and forward mulficasi39 dafagrams ES 1528 Computer Networks Mul ricas r one sender To many receivers Applica l39ionIayer muicas end sys rems involved in mul ricas r copy and forward unicas r da ragrams among The mse Ives ES 1528 Computer Networks 5 Infernef MulTicasT Service odel 128591612 12811940186 7 mulficusf j i 1283410863 group 226 1730197 1283410860 mul ricas r group concept use of indirection hos139s addresses IP dafagram To mul ricas r group routers forward multicas r dafagrams To hos139s That have joined That multicas r group E13 1528 Computer Networks Mul ricos r groups 3 D In rerne r addresses reserved for mul ricos r i111o Multicast Group ID u hos r group serpon rlilcs I 2 bits a 0 anyone can Jom receive mu TICClS I39 group 0 anyone can send To mul ricos r group 0 no ne rworkoner identification To hos rs of members a needed infros rruc rure To deliver mcos roddressed do rogroms To all hos rs Tho r have joined Tho r mul ricos r group ECS 1523 Computer Networks Joining a mcas r group Twos rep OCCSS ca39 hos r informs local mcas r rou rer of desire o join group IGMP Inferne r Group Managemen r Pro rocol wide area local rou rer in rerac rs wi rh o rher rou rers To receive mcas r da ragram flow many profocl DVgUEP MOSPF PIM mu roufing 3 EB 1528 Computer Networks 8 IGMP InTer neT Group ManagemenT Pr oTocoI r oTocoI beTween a hosT and iTs dir ecTIy aT ached r ouTer The hosTs informs The r ouTer ThaT The hosT wanTs To join a specific muITicasT group A muITicasT rouTing pr oTocoI To deliver The packeTs To The r ouTer s PIM Pr39oTocoI independenT MuITicasT VMRP DisTanceVecTor39 MuITicasT RouTing Pr oTocoI EB 1528 Computer Networks 9 IGMP In rerne r Group Manageme roTocoI host sends IGMP repor r when applica rion joins mcas r group IPADDNENBERSHIP socke r op rion hos r need no r explicile unjoin group when leaving mufer sends IGMP query of regular intervals hos r belonging To a mcas r group mus r reply To quenx EB 1528 Computer Networks 10 Internet Control Message P Tocol IGMP e 0 Transport pro rocol more or less RFC 1112 c 2236 Physical E13 1528 Computer Networks szxll IGMP Thr39ee messages Membershipquery message Membershiprepor r message Leavegroup message EB 1528 Computer Networks 12 u w are messages delivered fo 1 specific mulTicasf group 223121 2231212 223131 2231315 EB 1528 Computer Networks 13 Mul hcasf Rou hng oal find a Tree of 39 ks Tha r connec rs r ou rer s Tha r have a r rached hos rs belong39wge ro a mul ri T oup Sourceibased Groupishared l LEGEND roufer39 wifh aH39ached group member 0 roufer39 wifh no aH39ached group member EB 1528 Computer Networks Approaches for building mcast ees Approaches sourcebased tree one tree per source shortest path trees reverse path forwarding groupshared tree group uses one tree minimal spanning Steiner centerbased trees EB 1528 Computer Networks 15 Sourcebased Tree n individual routing e is constructed for ch sender in the multicast group In a multicast group with N hosts N different routing trees will be constructed for each sender in the multicast group EB 1528 Computer Networks Groupshared Tr39ee single r ou ring Tree cons rr uc red for The en rir e mul ricos r group EB 1528 Computer Networks 17 Shor39TesT Pa rh Tr39ee mcas r forwarding free free of shor res r pa rh r ou res from source To all receivers Dijksfm39s algorithm EB 1528 Computer Networks 18 When a rouTer receives a muITicasT packeT wiTh a given source address iT TransmiTs The packeT on all of iTs ouTgoing links excepT The one on which iT was received only if The packeT arrived on The link ThaT is on iTs own shorTesT paTh back To The sender OTherwise discards The packeT EB 1528 Computer Networks 19 Pruning hen a router receives wanted multicast ckets an as no attached hosts joined to that multicast group will send a prune message to its upstream router If a router receives a prune message from one of its downstream routers then it can forward a prune message upstream source EB 1528 Computer Networks 20 Centerbased tr39ees single delivery tree shared by all one router identified as quotcenter bf tree to join edge router sends unicast joinms addressed to center router joinms quotprocessedquot by intermediate routers and forwarded towards center joinms either hits existing tree branch for this center or arrives at center path taken by joinms becomes new branch of tree for this router EB 1528 Computer Networks Multicast Routing t DVNRPi Distance Vector Multicast Routing Pr39ot Sourcebased trees with RPF details RFC1075 0C0 I MOSPF Multicast Open Shortest Path Fir39st Sourcebased trees CBT39 CoreBased Tr39ees Groupshared tree InterAutonomous System Multicast Routing eg BGMD Border Gateway Multicast Protocol PIM Protocol Independent Multicast Two modes densesparse according to members EB 1528 Computer Networks 22