Tim Hieu MANET

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Transcript of Tim Hieu MANET

TNG QUAN TM HIU MNG MANET

MC LCChng 1 : Gii thiu mng MANET Chng 2 : K thut v ng dng mng MANET 2.1 K thut mng MANET 2.1.1.M hnh phn lp mng OSI trong mng Ad hc 2.1.2.Chun Bluetooth 2.1.3.Chun IEEE 802.11 2.2 Nhng ng dng trong mng MANET 2.2.1.Trong qun s 2.2.2Trong mng cc b 2.2.3. Trong trng hp khn cp 2.2.4. Mch mng cm bin khng dy Chng 3 : Multicast trong MANET On Demand Multicast Routing Protocol (ODMRP ) Multicast Ad hoc On-demand Distance Vector Routing Protocol (Multicast ADODV ) Fowarding group multicast protocol (FGMP) Chng 4 :nh tuyn trong mi trng MANET Cc nghi thc trong nh tuyn mng c nh Cc nghi thc nh tuyn trong mng MANET: 4.1 Proactive protocols 4.1.1.The destination Sequenced Distance vector (DSDV) 4.1.2.The Optimizrd Link State Routing (OLSR) 4.1.3.The Fisheye State Routing (FSR) 4.2.Reactive Protocols 4.2.1.The Dynamic Source Routing (DSR) 4.2.2.The Ad hoc On demand Distance Vector (AODV) 4.3.Hybrid protocol: ZRP

1. GII THIU CHUNG:Trong nhng nm gn y,vi s pht trin nhanh chng cc thit b di dng ( Laptop,personal digital assistant PDA,cc thit b k thut s cm tay.) to nn mt cuc cch mng mi trong ngnh din ton.Vi yu cu i hi mng mng tnh linh ng v c th kt ni mi lc,mi ni m khng b gii hn v kin trc h tng m mng my tnh truyn thng i hi ( nh trm thu pht gc,Access point,cc b nh tuyn),m hnh mng MANET c hnh thnh v pht trin ngy cang hon thin. Mng Mobile Ad Hoc Network l mt h thng nhng im mng khng dy trong nhng im mng (node ) c th di chuyn t do v t t chc thnh m hnh mng bt k v mang tnh nht thi,cho php ngi s dng c th cu thnh mt internetwok m khng i hi bt k c s h tng no v vn thng tin lin lc.

L mt mng li truyn d liu,mng MANET cng chu nh hng ca nhng kh khn ca mng khng dy truyn thng nh vn bng thng ng truyn,iu khin nng lng hay nng cao cht lng cng nh tc ng truyn. Bn cnh , vi bn cht l mt mng linh ng v hnh dng, cu hnh mng thay i lin tc ngu nhin v thiu cc c s h tng c nh lm ny sinh thm vn v tm ng, duy tr ng truyn trong qu trnh truyn ti d liu. Nhng c im chnh ca mng MANET bao gm: -Cu hnh mng thay i lin tc v bt k trong qu trnh truyn d liu -Do vic s dng knh truyn khng dy dn n s hn ch v dung lng v bng thng. -Hn ch v mt bo mt cc knh truyn. -Do bn cht l s lan truyn sng v tuyn nn chu nh hng ca s mt mt gi d liu ln, chu delay ln hn mng c nh. -Cc node mng trong mng Ad hoc s dng ngun nng lng ch yu l pin.V th tit kim nng lng l mt tiu chun quan trng trong vic thit k h thng. Mt c im quan trng khc ca mng Ad hoc l s c lp v cu trc v quyn u tin, cung cp mt tim nng ln cho ngi s dng. M hnh mng n gin nht c th to ra vi ch 2 nodes mng khong cch gn c s lan truyn sng m bo cho s truyn thng tin gia cc nodes.

2.K THUT MNG MANET V CC NG DNG: 2.1 K thut mng MANET: 2.1.1M hnh phn lp mng OSI trong mng Ad hc :M hnh OSI-Open System Interconnection bn cht gm c 7 phn lp mng,c ISO a ra vo nm 1978 chun ha li cho d pht trin v cho php kh nng kt hp gia nhng dng sn phm khc nhau trong mt mng.7 phn lp bao gm : Application > Presentation > Session > Transport > Network > Data link > Physical

y ta tm thi khng quan tm nhiu n 3 phn lp u v tm thi xp chung chng li thnh mt phn lp chung l lp ng dng APPLICATION.Sau y ta s ln lt phn tch c im tng phn lp: Lp ng dng APLLICATION :

Lp ng dng l lp gn gi vi ngi dng hn ht,n cung cp cc ng dng ca ngi dng.N khc cc lp khc ch khng cung cp dch v cho bt k lp no khc,thay v vy,n ch cung cp dch v cho cc ng dng nm bn ngoi m hnh OSI.Cc chng trnh ng dng nh cc chng trnh x l bng tnh,cc chng trnh x l vn bn ,cc chng trnh u cui.Lp ng dng thit lp tnh sn sng cho cci tc thng tin,ng b ho v thit lp tnh nht qun trn cc th tc khc phc li v kim sot tnh ton vn d liu c bit trong mng Ad hoc th lp ng dng cn chu trch nhim cho vic cung cp cc ng dng lin quan n v tr (location based services).

Lp vn chuyn TRANSPORT:

Lp vn chuyn phn on d liu t h thng truyn v ti thit d liu vo mt lung d liu ti host nhn.Lp vn chuyn c gng cung cp mt dch v vn chuyn d liu,to nn mt di ngn cch bo v cc

lp trn trnh cc chi tit hin thc vn chuyn bn di.c bit cc vn nh lm th no vn chuyn gia 2 lp host tht s tin cy l trch nhim lin quan n lp vn chuyn .Trong vic cung cp dch v truyn thng,lp vn chuyn thit lp,duy tr v kt thc mt cch tt p cc mch o.Trong vic cung cp cc dch v tin cy ,s pht hin li,khc phc li cng nh iu khin lung thng tin u c d dng trit . Trong mi trng MANET,s di chuyn cc node s lm cho gu ht cc gi nhn u khng theo ng th t do s tr ca gi ACK.i vi mng MANET c mi trng tnh th s mt mt gi ch yu do li trong knh truyn khng dy.S truyn li l rt hn ch v tiu tn nng lng .V th khi thit k mt lp vn chuyn hiu qu cho MANET,nhng vn sau cn c quan tm. Kch thc ca s phi c iu chnh sao cho khng ch ph hp vi li knh truyn v tr u cui,m cn phi ph hp vi s di chuyn c ng gia cc nodes. Nh cp trn,trong mng Ad hoc n nh th mt mt gi l do li ca knh truyn v do tr u cui. Thi gian Time-out dng ch khong thi gian giao thc phi ch trc khi gi li phi c tnh ton sao cho ph hp vi s c ng ca mng .R rng nu khong thi gian ny gim xung s lm tng s ln gi li v nu tng time-out ln th s gim s lng gi vo a vo mng. Ngun gc ca vic iu khin tc nghn l da trn s tr ca qu trnh xc nhn.iu ny ko chc chn l tt i vi mng Ad hoc v tr y l do li knh truyn,kt ni b hng (do cc node di chuyn) v s ng lp MAC m nguyn nhn khng ch do lu thng ca mng m cn do ln (s lng node) ca mng. Cc nghin cu v giao thc lp vn chuyn dnh cho MANET tp trung cho vic pht trin c ch phn hi sao cho gip lp vn chuyn nhn bit c s c ng ca mng,iu chnh thi gian time-out v kch thc ca s cho ph hp v thc hin iu khin tc nghn da vo nhiu thng tin trn mng hn.Chng hn khi mt phin c bt u,lp vn chuyn gi s rng tuyn tuyn sn sang cho mt khong thi gian.Khi tuyn c thay i,lp vn chuyn s c thng bo.Sau vic truyn d liu s c tm ngng cho n khi c tuyn mi c thit lp. Lp mng NETWORK: i vi lp mng th nhim v quan trng

nht ca n l nh tuyn.Nhng kh khn gp phi ca mng Ad hoc trong vn nh tuyn bao gm: - Node trong MANET thng thng gm cc thit b cm tay v laptop vi lng ti nguyn hn ch - Node trong MANET thng di chuyn lin tc.V th p ng vi cu hnh mng thay i lin tc,giao thc nh tuyn ca mng Ad hoc phi tm c v thay th tht nhanh cho giao tuyn c b h.Tuyn mi

tm c cng nhanh th cng quyt nh tnh hiu qu ca giao thc nh tuyn Lp lin kt d liu DATA LINK:

- c CISCO chia lm 2 lp con LLC ( Logical link control ) v MAC ( Media Acess Control ). Lp MAC chu trch nhim qun l vic truy xut knh truyn , v LLC th lin quan n vic duy tr kt ni ,ng frame d liu , ng b , pht hin li , kh nng phc hi v iu khin lung thng tin - C 2 k thut dng xy dng nn mng Ad hoc : IEEE 802.11 (chun mng cc b khng dy WLAN) v cng ngh Bluetooth (Chun mng cc b c nhn WPAN ).Bluetooth v IEEE 802.11 l c trng ca 2 phng php a truy cp mng : truy cp ngu nhin v truy cp theo kiu token ( node no nhn c token mi c php truyn d liu ).Do tnh mm do vn c ca cch truy cp ngu nhin (cc node c di chuyn khng gii hn ) nn y ban IEEE K.11 quyt nh thng qua cch truy cp ngu nhin, da trn CSMA cho mng WLAN.Ni cch khc truy cp kiu token thch hp hn i vi mi trng mng i hi v QoS ( Quality of service ) Trong mng c c s h tng c node iu khin trung tm cho mi cell,thng l access point.Access point c kt ni vi mng c dy. Tt c lu lng u i qua Access point ny ngay c khi mt thit b d liu cho thit b cho thit b ch thc thuc cng mt cell.Cc cell k cn s dng tn s khc nhau trnh nhiu v tng dung lng cell.Tt c cc cell link lin kt vi nhau lp LLC Trong mng Ad hoc,mi thit b nm trong cng mt cell hay Independent Basic Service Set ( IBSS ) ,do cc thit b c th giao tip trc tip vi cc thit b 802.11 trong cng mt cell m khng cn bt c s can thip no ca node iu khin trung tm.802.11 gip mng Ad hoc tit kim cng sut.iu ny rt quan trng i vi mng Ad hoc Giao thc multicast trong mng c dy bao gm 2 giao thc : -Shortest path multicast tree -Core-based trees multicast protocol Thng thng c 2 tiu chun mng Ad Hoc phi p ng: -Chun 802.11 chun cho mng WLANS -Chun k thut Bluetooth dnh cho short-range wireless communication

2.1.2.Chun IEEE 802.11:IEEE 802.11 c thit lp nm 1978 bi Institude of Electrical and Electronic Engineers ( IEEE ).IEEE 802.11 l chun truyn d liu s khng dy bng tn 2.4 Ghz IMS.C 3 cng ngh khc nhau c s dng xy dng lp vt l l : tia hng ngoi,frequency hopping spread spectrum ( FHSS ), Direct sequence spread spectrum ( DSSS ).Cng ngh ph bin nht hin nay l DSSS,s dng cng ngh c th cung cp tc trn 11 Mbps bng tn 2.4 Ghz,v trong tng lai c th trn 54 Mbps bng tn 5 Ghz. Phng thc truy cp c bn ca 802.11 MAC l Carrier Sense Multiple Acess with Collision Aviodance ( CSMA/CA ). Chun 802.11 c th s dng cho c mng WLAN c c s h tng v c mng Ad hoc LAN. Giao thc 802.11 cung cp 2 tin ch: -BSS( Basic Set Service): kt ni cc thit b khng dy u cui vi AP (Acess protocol) -IBSS(Independence Basic Set Service);phng thc kt ni theo kiu Ad hoc cc thit b u cui m khng cn kin trc h tng v AP 36 Cc chun 802.11 thng dng:Thng dng : 802.11a,802.11b,802.11g Bo mt : 802.11i ang pht trin: 802.11n Cc chun khc cng h nh c-g,h,j ang c ci tin v m rng,sa li 802.11b c p dng rng ri u tin,k l 802.11a,802.11g Chun 802.11b v 802.11g pht bng tn 2.4GHz,do c th b nh hng bi Microwave,cordeless telephone v Bluetooth,v cc thit b khc dung cng band tn Chun 802.11a pht bng tn 5Ghz nn ko b nh hng bi cc thit b hot ng bng tn 2.4GHz

Cc thng s k thut ca chun 802.11 v Bluetooth.

2.1.3.Chun Bluetooth:Bluetooth l chun truyn d liu s khng dy hot ng bng tn 2.4Ghz ISM, vi khong cch truyn ngn gia cc laptop, cellphone, hay cc thit b khc. Bluetooth s dng k thut nhy tn s (frequency hopping) truyn dn d liu, tc truyn dn 1600 hop trn mt giy. Thi gian gia hai hop gi l slot, mi slot s dng cc tn s khc nhau. Mi hop chn ngu nhin 1 trong s 79 tn s. mt s quc gia, bng thng sn c l 80MHz v th mi hop chim bng tn 1 MHz. Bluetooth pht tn hiu rt b, ch 1mW, cong sut pht ca cc cellphone ch 3W, v th khong cch truyn dn trong Bluetooth tm 10m. Cng ngh Bluetooth c cu trc thnh mng ad hoc piconet, vi hai hay nhiu thit b m khng cn bt c mt c s h tng no c. Trong mt piconet gm c mt thit b master v nhiu thit b slave. Mt thit b slave c th thuc nhiu picone