Nghiên cứu sự ảnh hưởng của chuyển động và giao thức định tuyến trong mannet.PDF

TONG QUAN VE MANET
CHUCING 1. TONG QUAN Vt MANET
Chuang nay trinh bay cac khai
niem tong
quan nit& ve MANET, cac img dyng
trong nhieu Huh vcre cutjc song cua MANET. Dting thtri, de cOp den cac thach thirc
ma
MANET dang phai 461 mot.
1.1 Mit diu
Mang may tinh to lau da ter thank mot phiin khong the thieu d6i veri nhieu
vyt din sting, xa hOi. Tir cac hg thling mang eye bO den he thong mpg town

nhu
Internet, mang may tinh dim mpi ngutri tren the gieri den
gAn nhau hon. MOi ngtan
duqc tiep can voi mot
ngu6n th8ng tin, tri thirc phong
Xa hOi phat
trien, con ngoai
von dung kh8ng ngimg, mot ngueri ket noi vao mpg
bin cap vet l5/ thi viec di chuyen mem hp se bi han che. Nhu
cau
clOt ra lit vita ket n6i,
vita
c6 the di chuyen 6 bit dr tin mot each dun gib. Dieu nay khien cho ngluth cling
nghiep mang khong day c6 tiem Ming phat trien mph me.
MANET let mot kieu mang khong day rat linh hoot. N6 11 top hqp elm hai hay
nhieu thiet bi doge trang bi khi Ming n6i mang va truyen thong khong day. Cac thiet bi
nhu vOy c6 the giao tiep yen tit ca thiet bi mang Ichic ngay kip tut trong dai vo tuyen
(yang phit sang, pham vi ma thiet bi mang 46 nhon biet duqc) hay mot thiet bi vo
tuyen khic nAm ngotli dai vet

'
tuyen cua
chin vai dieu kien c6 cac node trung gian de
chuyen tiep th'Ong tin ter node ngu'6'n den node dich. Thiet bi ho trq MANET da clang
va sir dyng kha ph6 bien nhu laptop, dien thoai di dOng Internet. Vi co nhieu uu the
vuqt trOi va nhittng thach thirc can gilti
quyet, ngity
nay MANET da va dang
duqc
nghien ciru
trien khai
titbit conga mot
s6
ntrac ma ph6 bien la MANET dk biet
hau ich trong cac Ung dung nhu khic phyc tham hpa thien nhien, qu6c phong, y
te, hOi
nghi nen c6 xu huang (mg dyng rung tai tren the giai.
1.2 Kluli nitm
MANET la
to
hqp cum cac node di dOng duqc ket
n6i
vtri nhau bing cac lien kit
khong day, cac node to do di chuyen nen kien true mang ce the thay 461 lien tic
ma
khong dy dofin duqc. Moi node mang c6 mot giao dien vo tuyen giao
tiep
ved cac node
mang khac thong qua sang vo
tuyen

hok hang ngoai. Cac mang nay kitting dung bit
cir stir he; trq ca s6 ha tang
mang c6
dinh hay chiu str quirt li t#p trung nao. Day la mot
dOc diem rieng biet cum MANET so vai cac mang khong day truy'en th6ng: mang chia
mang WLAN, trong do cac node (cac thue bao di dung) lien lac veri nhau thong qua
tram vo
tuyen
ca 56.
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TONG QUAN VE MANET
Ilinh 1.1 sMo hinh mb lib khcii niem MANET
Trong MANET kh8ng ton tai khii niem quirt ly top trung. N6 dim bito mang se
khong hi s$p vi truing hqp nit mpg di chuyen ra ngoai khoting truyen din ctia cac
nut mong khac. Nut mong co the ra vao bat cu lac nio. Do khoang truyen din dm nut
mang lit han cht nen chfing trao deri thong tin bang phuong phap truyen gen tin qua
nhieu btrerc (Multihops). De lam duce dieu nay, thi tat ca ale nut mang phai ce khi
nang chuyin tiep gen tin den nut mong khic, do voy tat ca cac nut mong trong MANET
c6 the hoot dOng nhtr may tram vi router. Nut mong co the bao gam met router va met
may tram lien ket yen nhau. MOt router thus hien cac giao thirc dinh tuyen, may tram
di Ong c6 dia chi IP.
MANET cling ci khi niing thqc hien thay dOi ve cAu hinh mang va khic phtic str
c6 cua
nut mpg thong qua till' tuc cau hinh Ini mpg. Vi du: Neu nut mang rbi Mei
mang se gay ra six
ceo lien
ket, nut mang bi anti huerng ea the yeu au duimg dinh tuyen
va van de se duqc giii quyet. Dieu nay se gay ra tre tren mang, tuy nhien yea

nguai sir dung MANET yin hoot dOng binh thuong.
MANET c6 nhieu uu diem cim mong truyen thong vo tuyen thong thutmg:
lien
ket gifts cac nut mang duqc hinh Wirth ngay khi chimg nim trong khoimg truyen
din
cim nhau.
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TONG QUAN VE MANET
1.3 D#c diem
MANET thuimg duqc mo to c6 cau truc mang they dii do stir thay doi vi tri dui
cac nut mpg. Cac giao thirc djnh tuyen c6 ca the tv phat hien cac thay d6i ve djnh
tuyen thong qua cac thultt town (firth tuyen thong thueng nhu vector Idioang cach vi
tang thai cac lien ket. MOt &lc diem !chic cila cac net mang trong MANET: bj ON
han ve kha nang dm CPU, X) nher, dung lizong pin va bang thong. Khi niing Itrong sir
dung bj gitri han ;coo theo gi6i han ve khi &Mg truyen din. Thiel N truy nhop, men
truing vo tuyen cling co cac d#c diem d(ic biet ma ngu&i this& k'e can km tam khi dim
ra cac giao they djnh tuyen cho MANET. Vi du: cac lien ket mot chi'eu, no St hien
trong trutmg hqp 2 nut mpg c6 cong sulk phat khic nhau nen co khoing truyen din
khic nhau, chi cho phip mot nut mpg nghe net mpg Ida. Lien kit mot chieu chi co
trong MANET, khong ton tai trong mang ti bao. Sir dung phucmg phip djnh tuyen
nhieu buck thi cac nut mang co the tiet kiem duqc Wing luting phit ra.
1.4 (rug dyng
MANET duqc Ong dung cho hOi thio, Ong dung trong quail sv. N6 cling dirge sir
dung cho trutmg hqp trien khai ca so ha tang mang la kW) khan. Vi khich hang co
the chia se tep tin de lieu o gm bay, sinh vien trao doi thong tin yeti nhau trong tiet
hnc Khi may tinh di dOng giao tiep th8ng qua giao di'en mpg LAN vo tuyein, thi
nhom cac may tinh de hlnh thinh MANET, khi de may tinh co the truy tulip Internet,
tai nguyen tren mang filar may in, may scan

1.4.1 Dick vg Min dip
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TONG QUAN VE MANET
Binh 1.2
Ong
dung cho chc dick vy khan
dip
kid cif thien tai
Bit 14 diu khi cep truerng hop khan *thy ra

cin ca Au ket hop cha ate Whin
vien ciru ha. Gill phi, thong thubng la dung thiet bj v8 tuyen. Tuy nhien, khi co so hg
ding bj hang holk kh8ng cbn host dung thl gill phip Ih gl? MANET chink lh chu trit
Iii
nhanh nhAt va pha hop nhAt. Dieu nay co the kheing nghia v6i khu vtrc
ton
that
nho, tuy nhien voi than hoe thien nhien c6 khu vtrc anh huerng tan phi rang letn, viec
lien lac nit quan tong nen MANET tr6 thanh gill phip httu ich.
1.4.2 MY nglei
Trong hOi ngh1, hOi thho an trao 461 thong tin gifts chc dui bieu hap v6i hOi
nghj khic. Day la mOt nhu eau lbn trong thin dpi phis trim nhanh
vi
thong tin nhu
hien nay, khi ml gill phip homenetwork chua that so sin sang. Gill phip hien tgi
la
sir dung clic mpg c6 son cho ate dal bieu them do tuy nhien ne co 40 tre lam, vi du
gill phip Mobile IP . VI MANET la gill phip chi& uu the.

HInh L3 ling dung trong ctic h¢i nghi
Train Van Tucin-A14325
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TONG QUAN VE MANET
1.4.3 Home Networking
1(0 rang au hien dien caa may tinh xich toy yr] Ong dung klgong day lam nhu au
ve
home network tang coo. Viec sfr dung
ky
thuit al* MANET cho phap Chung ur au
hinh va hinh thinh mang, diet' nay tien lqi cho ca ngubi khOng that au am hieu ye
mpg cling nhu gam thurc chi phi cho xity dung thief ke mpg. Han rata, neu to ce
nhu au sir dung may tinh 6 dog so, trutmg huc thi kh6i lirqng thong tin quirt mpg
giant
xutong ro rat
Rink 1.4 Ong dung cho home networking
1.4.4 Myng cd Wain (PAN)
6
thtri dpi thong tin till 1 ngubi an mang then nhieu c8ng cu h8 trq cho Ong
viec (dien thaii, Palm. . .) khi chang duqc lien kit v6i nhau hlnh thanh mpg a nhan
PAN thi a) rang mang lai Mau tien ich han cho ngubi sit dung. PAN Li mpg di gang
do con ngubi klgong the
ng6i yen melt cht3,

tuy nhiin khi kit neoi vai ming PAN khic
can trq glop ala MANET.
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TONG QUAN VE MANET
Binh 1.5 Ong dm cho wing ai Man
1.4.5 Hi thing nkung (anbetkd system)
Ngly cling c6 nhieu may mac can kit n6i yen nheng vat xung quash Uri then
nhu au cos MANET. No c6 the la d6 choi co kith !ging kit a& mpg, twang tic
duqc
vbi
home network de tim kiim (lit lieu ben Internet hock c6 the kit n6i
vai
din thoai,
c6 the dieu chinh volume cutt TV khi c6 cuOc gqi din dip (mg nhiiu nhu ciu cM
ngueri sil dung.
1.4.6 Ming xe 4 (vehicular network)
VANET (Vehicular MANET Network) goi la mpg xe cO MANET, la he thing
ming khong can co se ha tang, dugs tao thinh tfr oic phuong tien xe c0 luu thong tree
dirtmg. Ch(mg duqc trang bi thiit bi thu phat di c6 the lien lac, chin se vi trap d6i
thong tin vii nhau gieng Whir mat nut trong MANET. Thong tin trao d6i trong ming
VANET bao gem thong tin
ye
luu luvng xe cO, doh trang ket xe, tai nail giro thong,
nguy lam can trinh va al nhang djch vy thong thiriong nhu djch vq da phuong lien,
Internet
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TONG QUAN MANET
Binh 1.6
Ong
dung cho wing xe
1.4.7 Mang cdm biin (sensor network)
Mang cam Men khong day la met ung dung then hlnh mkt MANET. Hien nay di
c6 nhdmg gain tam ding ice cho sit phit tan kilo man nay, chit yeti li trong gain sit,
cong an, tinh bio, kilo c6 hqc, nghien citu dia I. . . Cic bit cim Wen c6 the to kich
thtroc nho nhung kha Laing truyin thong va luu tri tuong &Si tot. Trong quail sit di
dung nhing may m6c hien dal nhung kich
a
gin nhu hat bui nen Ai phuong nit khe
phit hien vi phi hay chimg.
Trong Huh Arc y te, ale b0 cam bien cho ph6p giant sit lien tuc thong tin lieu
chum
ire MI
song. Trong tong nghe thuc phim, k9 thuot ship cam bien duqc ip dung
de gum sit chit Itrqng to the gitip ngin mitt cic sin phim khong chit yeu citu nth
tang
mirk
thou min cho khich hang. Trong ding nghiep, the bit cam biota to the giim
xic dinh chit luqng dit tr8ng vi dO im, chimg ding ce the phit hien cic hqp chit
kink. Ngoii ra, cic b0 cam Wen ding duqc sus dung rang trong th8ng tin thin ties vi
moi trutmg.
1.5 Nhttng thick thin 661 vet MANET
L5.1 C7s1 phi cho vifc drag
this
se
taw
het

the
MANET this nghiem hien nay du
dna tea
bang tin ISM. De ngin
ngira nhilu, MANET phii host dung qua met so dii phi cu the No d6, duqc cep phit.
Ph6 tin khong chi duqc cAp phit vi giim sit chot the ml con cin phai dtrqc frit phi.
1.5.2 Co chi tray nk#p
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TONG QUAN VE MANET
Khong gitmg nhu mang to bao, trong MANET khong co sir dieu khien tip trung
va dOng bo toim cvc. Do d6 cac phucmg phap da truy nh#p truyen thong nhu TDMA vi
FDMA khong con thich hop nut Ngosi ra, nhieu giao thirc dieu khien truy nh#p
phuong tien MAC (Media Access Control) cling khong giai quyet dirge sir di dOng elm
aft mang. Do v#y, cac icy thuot 1#p ljch trinh vi djnh thin de h6 thy QoS gip nhieu kh6
khan.
Trong MANET, do cimg mOt phuong tien truyen thong dirge chia se boi nhieu
ben tham gia nen dal tic truy nhkip den kenh chung phai dugc thvc hien theo kieu phan
bo
nh6 sir h6 trg cua giao thirc MAC. Giao thirc MAC phai tinh den truy nh#p kenh
trong khi dOng than phiti tint' duce sq xung dOt vOi cac nut Ian c#n. Do va'y, khi firth
toast thiet ki cac giao thirc MAC cho MANET phai tinh den khi riling di chuy'en, van
de du cu& An va cac van de lien quan khic.
1.5.3 Dfrth tuyin vd chuyln flip gdi tin trong MANET
13#c tinh dOng cim MANET gay ra sq thay den thtemg xuyen va kh6 dorin try&
cua
topo mang, lam tang do kh6 va dO phirc tap de djnh tuyen gifts cac nut di dOng.
Nhieu giao thirc vi thuot toan djnh tuyen di dirge de xutit cho MANET, thy nhien mai
giao thirc lai co mot hart the rieng. Do vf)y, nghien ciru ve cac giao thirc djnh tuyen

trong MANET la mOt van de rat quan trong.
1.5.4 Hiss cud sir dung nguein nuoi
HAu
het cac giao thirc trong mang hien nay khong quan tarn den fieu ton niing
lircmg nguon nuoi vi ciic may chic vi ciic b0 tinh tuyen thubng duct gia djnh la tinh va
dugc cap nguon tir ngu6n dien chinh. Tuy nhien, cac thiet bi di dOng hau het dugc cap
nguon ti nguon nag dOc lip. Kg thulit nguiln nuoi vim thirimg di chin hun so yen
ky
thuat vi xis ly. Thai gian cap nguon dm pin loyi tot nhu Li-ionh hien nay cling chi ttii
da tir 2 den 3 gib (hien nay da co mOt se• laptop co thbi gian sir dung len den 8h, tuy
nhien gia thinh van con kha cao). Sv gi6i hart than gian hog dong nhu the mai len tinh
can thiet phai bao ten tot nguon nuoi. Difc biet, din yen MANET, do cac this& bi di
ding phai thirc hien vai tr6 cim ca he thOng diu can (twang tic ngueri dimg khi thvc
hien cac img dung nguai dimg) lim vai tr6 cua mOt he thing trung gian (chuyen tiep
gei tin) nen se tieu ton niing lin:mg nguon nuoi mOt cach dang ke, d#c biet la cac nut
trung gian.
1.5.5 Dr tittle TCP
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TONG QUAN VE MANET
TCP (Transmission Control Protocol) la met giao thirc
cutn-cuSi
duqc thiet ke
phvc vv viec dieu khien nghen va dieu khien
luting
trong mang. TCP la met giao thirc
huffing lien ket nen can c6 met giai doan thiet lop ket not uu tien cho viec truyen
dtY
lieu.

Ket not
bi loci be khi viec truyen da lieu hoin think. Val intend hien nay, giao
thirc mang IP li phi ket not nen an co met giao thirc truyen din luremg ket not ding
tin coy qua met giao thirc mang khong tin coy. Tuy nhien, TCP gii sir ring cic nut
trong tuyen la tinh nen viec dieu khien nghen vi dieu khien luting chi duqc thvc hien
cic nut
ngu6n
vi dich.
TCP dip vio viec do dac thin gian thin trinh-RTT (Round Trip Time) vi mirc
ton tht gel de ket luon la cif) nghen mach xiy ra trong mang hay khong. TCP kh8ng
the phiin biet duqc sq co tinh di Ong vi skr nghen mang. Cic nut chuyen di
e
ing
trong met kit not c6 the giy ten thAt gel vi liun cho RTT dii hon. Do voy,
an
co met
so
cii
lien
de bio dim ring giao thirc any& din thvc hien
tot ma thong
inh larding
den thong ligmg
truytn
thong
cu6i-cu6i.
1.5.6 Club lufmg dick vp (QoS)
Khi nang cung cap QoS cua met mang phv thuec vio cic dk tinh ben trong cfia
toin be the thinh phin mang, tir cic lien ket truyen phit den tang MAC vi tang mpg.
Cic ket not khong day c6 niing hp thip vi hay thay doi, ti le

18i cao. Cic topo mpg
Ii
deng vi c6 tY le mat goi cao. Cic giao thirc MAC dip tren truy nhOp
ngiu
nhien khong
he toy QoS.
Cic giao thirc MAC QoS giii guy& van de ve xung det phtrang tien, h6 trq
truyen thong unicast tin coy, vi cung
cap viec
dq trey tai nguyen cho cic luu Itripg thou
gian thvc trong mei twang kh8ng day phin tin. Riit nhieu cic giao thirc MAC vi cic
cii tien dirge de xuat de cung cap viec dim bio QoS cho luu Itopg thed gian thvc
trong mei truang khong day phin tin bao gem giao thirc GAMA/PR vi co the xung
det BB.
1.5.7 Tinh an loin vd bdo
mkt
M6i truing vo tuyen trong MANET la "mei ngon bdo be" cho cic cuec dui cong
ma° dank do dAc tinh quing bi ciut no. Cic giao thirc djnh
tuyen
trong MANET
can
c6 ho trq tinh nAng xic thvc, mA him de ning cao tinh an toin, hien ntig cua mpg.
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TONG QUAN VE MANET
TONG KET
Chuang nay da trinh bay nhang ly thuyet
tong quan ve
MANET. Trong

MANET, topo ming thuang xuyen thay &Si. Do vay, cac giao thfrc djnh tuyen trong
MANET can
giii quyet stir
di chuytn cfia nut, ring buijc rang lugng, bang thong.
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DINH TUYEN TRONG MANG MANET
CHUONG 2. DINH TUYEN TRONG MANET
D#c tinh dOng cua MANET gay ra str thay d6i thutong xuyen va kh6 down twee
cua
topo mpg, lam tang dg kh6 va do
.
phirc top de djnh tuyen giaa cac nut di &Ong.
Nhieu giao thirc djnh tuyen duqc dua ra, toy nhien, chimg
van
gap phai mOt
s6 han
chi
that djnh. Chucmg nay trinh bay 4 loci giao thee trong MANET: OLSR, AODV, DSR
va DYMO.
2.1 Giao thee djnh tuyin d diin
Hien nay, cac giao thirc djnh tuyen dua ra vei MANET deu dqa tren mOt giao
thirc djnh
tuyen c6
dien lam thuot town ca ban. Do de, viec tim hien nghien cuu the
hoot dOng cc ban dm cac giao thee nay IA het sire can thiet.
Giao thirc
c6
dien nhu: djnh

tuyen
theo vector khoang each, djnh tuyen theo
tong thai lien ket da duqc se clung tir rat lau vi da ter nen rat quen thuOc. Tuy
cac
giao thee nay chi thich hop cho eau tree mpg firth, hoot dOng hieu qua er MANET
c6 toe dO di chuyen thap, cau true mong it thay deti. Ngoiti ra, giao thirc nay hoot (long
phv thuOc vAo ban tin dieu Ichien djnh
tuyen, nen yeti 56 Itumg nut mong
tang, you cau
trao d6i gifts cac net mong tang len, thong tin cep nhot djnh tuyen km, chimg se tieu
ton bang thong, nting ltrong va CPU. Bei vi hai loci giao thirc djnh tuyen tren duy tri
djnh
tuyen
den tat ca cac nut mong, net khong quan tam nut mong c6 tham gia truyen
thong tin trong mong toi moi then diem hay khong. Hon nfta, giao thtic djnh tuyen
co
dien rang butjc lien ket phai la hai chieu, nen an c6 nhUng cai thien nhAt djnh cho
thong tin vo
tuyen
not chung vi MANET nal rieng.
2.1.1 Dinh tuyin
Ara
tat hating
thdi lien
kit
Phucmg phap djnh tuyen dva tren tong thai lien ket dua tren gia dm mei lien ket
(cost) va net mong phiti duy tri cau tnic mpg hart chinh vei tham
s6 nay.
Tham s6
"gia" se duce cap nh(it bang each

mai not
mong se gin thong tin quang bit mOt each
lien tic "gia" cua cac lien ket xuat phat tir ne tai tat ca the nut mong khac sir dung
thuot town flooding. Mei net mong khi then duce cac thong tin nay se cep nh(it cau
trite mong va sir dung thuot town tim duting di ngiin nhat de chon nut
mpg tiep
theo
cho &rang djnh tuyen den nut mpg khfic. Lien ket c6 the c6 gia khong chink xac do
nhieu nguyen nhan nhu tre dtamg truyen, sr phan tach cua mong. . . Cac eau hinh
mong thay d61 c6 the hinh thanh djnh
tuyen
khep kin (loop), toy nhien, dirtmg djnh
tuyen kieu nay c6 th6i gian tan toi ngin vi chCmg se hi x6a ngay khi ban tin da di qua
toan bo mong.
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DINH TUYEN TRONG MANG MANET
2.1.2 Dinh tuyin Ara trill vector Hooting each
Phuang phap nay djnh thy& dqa ten vector khoitng each, ce cei tien ham so v6i
phuang phip djnh tuyen dua tren tang the*, lien ket:
mtii
nut mpg chi giam sat gie dui
lien ket xuit phat tir nO, ve khong queng be thong tin den tit ce nut mang; ne giri
queng be deu On den nut lien earth thong tin ve khoimg each ngin nhAt tin nut khec
trong mang. Nut mang khec khi nhon duce thong tin nay se tinh town Iii bang dinh
tuyen thong qua thuk toan tim throng di ngin nhit.
Giao thirc nay hoot dOng hieu qui hon, don glen hon va yeu
eau it
by nha hit frit

hon. Song, ne ce the sinh ra dutmg djnh
tuyen
1chap kin ce thbi gian rim t i thay d6i
dei non khk nhau, vi bang djnh tuyen c6 the xiy dung tir th8ng tin di ton tai lau qua
tren mang (khong duqc c#p nhk).
2.2 Giao that
Malt
tuyin cho MANET
2.2.1 Clic yiu ciu cluing
Do cac nut trong MANET luon di dung vit c6 nhien d#c tinh khk biet nen khong
the ep dung cac giao thk dinh
tuyen
thong thutmg. Cac MANET thirtmg dirge dfic
trtmg bai mOt topo dOng do cac net di chuyen lam thay doi vi tri vitt 19 dm chimg. DOi
yen MANET, giao thirc djnh
tuyen
dOng to ra hieu qui ve phu hqp hon cac phuong
phap djnh tuyen dye tren vecto khoeng each vi tang thai lien ket. Thach thirc trong
viec thiet ke cac giao thin djnh tuyen le khi 'ing cop nhot duqc mire di dOng ciut
nut
mang. Chich mire di dOng nay le nguyen nhen lam thay doi thin by eau
trim
topo dui
mang.
Mgt not di clOng thutmg bj gitii hart bin kite nking xi! Iy cita CPU, dung ltrqng
luu try, cong suit
nguen
ve dei thong.
M8i trutmg troy cop, moi trutmg v8 tuyen cong co nhOng thuOc firth dkic biet ci
►

phei chit y khi duet ke cac giao thirc cho MANET. Vi dy cac duong truyen vo Ming.
Nhing &Ong truyen nay xuit hien khi hai nut ce tiding det khic nhau ve cho phep chi
mOt nut nghe duce nut kia. Nhung chimg cling c6 the xuit hien do nhieu tir min truting
xung quanh. Da ch#ng trong mai Huang vo
tuyen
c6 the gay ra Wing ich cong suit
truyen ve tang ich cong suit do mOi quan he can bk hai gifta veng phu sting ve cong
suit phat ra. Bing each su dung da chking, cac nut c6 the truyen cac gei tin di sir dung
cong suit ra thip.
Hinh 2.1 M8 to cac true ca ben c6 the sir dung de dOe to m8i throng MANET.
True &Au tien le
so
cac irk trong mang. True thfr hai le tic dO ma tai d6 topo inking
thay d6i. True thir ba le tai hru luqng trong mpg. Khi moi twang di chuyen tir gOc
Tran Van Tuan-A 14325
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14
DINH TUYEN TRONG MANG MANET
dm 3
trnc,
van de djnh
tuyen tit nen
Ic.h6 khan han. Tang se nut, tang tee do thay dig
topo (nghia IA tang filth di dOng ciut nut), hoac tang tai Itru luqng mong muen tren
mang la thich thirc dei v6i cac giao thin trong MANET.
Hinh 2.1 He ton da ca ban me ki moi inning MANET
You cau dei voi mOt giao thirc djnh tuyen cho MANET la gi? Sau day la mOt se
you cau quan trong:
•

Hoot dong phan tan: Giao thirc djnh tuyen trong MANET phai II giao thirc
phan tan yeu cau dO tin c#y cao. Do cat nut 11 di dOng nen giao attic djnh
tuyen t#p trung la khong phe hqp. M8i nut mong phai dii th8ng minh
de t4to
cite quytt djnh djnh tuyen ml dung cac net lan
•
Khong lap yang: De fling cao chat Itrqng hoot dOng, giao thirc djnh tuyen
can dam bito dubng djnh duqc cung cap khong bj lap yang, dieu nay se lam
gram Ian phi bang thong vi cong sat tieu hao cua CPU.
•
Sir dung cac sieu

Tat ca cac giao thirc hien cto deu gia djnh rang tic nut
di dOng lit c6 ding cac dac firth dua tren ban chat elm mong ttr
t6
chirc la tip
hqp tint tic net ngang hang. Mac di
►

dieu nay c6 the clang trong mOt se
truing hqp, tuy nhien, c6 truing hqp ma 6 de mong ca cac nut c6 bang
thong cao,
ngu6n
nu8i
On
djnh, lien ket khong day tee dQ cao han so vol cac
nut khac. Cac not nhu v#y
duqc
gqi II cac sieu nat. Cac mang t‘r
t6

chile
trong truing hqp nay thutmg c6 cau frac 2 mac: vimg backbone vit vimg
Than Van Tuetn-A 14325
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15
DINH TUYEN TRONG MANG MANET
phy. Wing backbone bao g6m cac sidu nut. Them vio d6 cac sieu nut
thuang duqc gia djnh IA c& de di chuyin thiip han cac not thuang de duy tri
su 6n djnh cita backbone. Ctic nut thtrang khong can co quyet djnh djnh
tuyen.
•
Hoot dOng dua tren yeu
au: Tel
thieu hoa phial thong tin dieu khien trong
mang, giao thirc djnh tuyen thuOc nhOm djnh
tuyen
theo yeu cAu co the dap
img duqc dieu nay. NO chi tim dtdmg khi can thiet vi khong quang bi thong
tin dieu khien lien tic.
•
Tinh tien phong (proactive): Trong
mOt se
twang hqp,
tre
km do host dOng
dip ten yen
cAu
IA khong chip nhon duac. Do d6 phai sit dung

tinh tien

phong neu tai nguyen ctia mang (ye m*t giai thong) niun trong khoang cho
phdp.
•
H6 trq cac lien ket met chieu: Mai twang vo
tuyen
ce the la nguyen nhan
hinh thanh cac lien ket theo mOt huang. Sir dung kieu lien ket nay va kieu
lien ket hai chieu se ding cao hien nang ciut giao thirc (Unit tuyen.
•
Bao met: M6i truang vo
tuyen rat de
131 tilt cong, khai thic thong tin, do d6
ma hOa vi chug thuc la cach bito mot thong thutmg nhAt duqc ap dung hien
nay. Win de la viec phan 134 cac kh6a va cac not trong MANET.
•
Bao tom nang

Nat mang trong MANET co the IA may tinh xach tay
hay loci client nho gqn khk nhtr PDA thtrimg co gi6i hin ve thai gian sir
dung caa pin, nen can c6 chi de cher (standby mode) de tiet kiem nang
luqng. Do do, giao thirc djnh
tuyen
sir
dung an he trq the
dO char caa nut
mang.
•
Nhieu duang djnh tuyen: Nhim giam
se Ian tac
dOng do str thay d6i ve cAu

tnic mpg va khi nhieu duang djnh tuyen bi nghen. Neu nhu met duang
djnh tuyen khong sir dung duqc ngra thi met duang djnh tuyen khk co the
thay the. Nhu vety, giao thus khang an khai tao lai tha tic tim dtrong.
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16
Ciao
thee AMY tayia tress MANET
DINH TUYEN TRONG MANG MANET
• HO trq QoS: Co nhiEu loci QoS can duqc str h6 trq cua cac giao thirc djnh
tuyen, no phi thuOc vim raw dich cogs mang; ching han, 116 trq luu ltrqng
thin gian thqc
2.2.2 Ph& loci
De
so sich vi phan tich cac giao thirc djnh tuyen cho MANET, cac phuong thirc
phan loai hqp l5/ 11 rat quan trqng. Cac phuong thirc phan loai giap cho cac nhl nghien
cuu
vi cac nha this& ke hieu doge nhang dac mrng khic nhau va mOi quan hg gita
cac
giao thuc. Cac dac trung nay chit yeu lien quan den viec tap him thong tin djnh tuyen,
den vai tit ma met nut co the dim nhan trong qui trinh dinh tuyen.
2.2.3 Dinh tuyin theo beteg, 4nIs tuyin Ono yht eiju vd t nh tuyin lai
Met trong nhang phuong thftc ph6 bien nhat de pain loai cac giao fink dinh
tuyen cho mang MANET la clua tren viec thong tin dinh tuyEn dirge tap hqp va doge
duy tri nhu the nao boi cac nut di dOng. Sir ding phuong thirc nay, cac giao thirc Binh
tuyen cho manh MANET doge phan chia nhu With 2.2.
Minh 2.2 Phan loci cac giao Mac djnh tuyin
trong
MANET
•

Cac giao thirc djnh tuyen theo
bang (table-driven): Trong phuong phip djnh
tuyen theo bang, cac node
trong
mang MANET lien
tic dinh
gia cac tuyen
tot
cac node de duy tri tinh Wong thich, cop
nhat cfm
th8ng tin djnh tuyen.
Vi
v4y, nits node nguiin co the dua ra molt dtrbng
djnh tuyen ngay lop
tire !chi can. Trong cac giao thirc djnh tuyen theo bang, tat ca cac node can
duy tri th8ng tin ye cau hinh mpg. Khi eau hinh mang thay riot, cac
cop
Trap? Van Turin-A 14325
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17
. DINH TUYEN TRONG MANG MANET
nhat dirge truyen Ian trong mang nhiim thong bao st
i
r thay doi. Flau het cac
giao tithe djnh tuyen theo bang deu ke thira vi siza doi dac tinh tucmg thick
tir cac thuot toan chon throng din ngin nhat trong cac mpg hilu tuyen
truyen th6ng. Cac thuat tan (filth tuyen theo bang ducrc sir dung cho cac
node cap nhot trang thai mpg vit duy tri tuyen bit ke c6 hit lucmg hay
khong. Vi v$y, tieu de thong tin de duy tri cau hinh mang d6i veri cac giao
thirc nay thtrimg la 16n. MOt so giao thirc djnh tuyen dien hinh theo bang

trong MANET Giao thirc djnh
tuyen
khong day WRP (Wireless
Routing Protocol), djnh
tuyen
vector khoang each tan tu dich DSDV
(Destination Sequence Distance Vector), djnh tuyen trang thai
ten
tin lien ket
OLSR (Optimized Link State Routing), djnh
tuyen trang
thai gee rung
(fisheye (Fisheye State Routing).
• Cfic giao thirc djnh tuyen theo yeu au (on-demand): Trong phurcmg phip
djnh tuyen theo yeu au, cac dtrimg din dirge tim kiem chi khi can thiet,
host dOng tim
tuyen
bao gom
ca tha tic
the djnh tuyen. Thu tic tim tuyen
ket thitc khi mOt tuyen khong dirge tim they hoc khong c6 tuyin khi dung
sau khi xac minh tan WO tap holm v1 tuyen. Trong mang MANET, cac tuyen
hoot dung c6 the ngimg do tinh di dOng ciut node.VI vay, thong tin duy tri
tuyen la tOi quan trong
d6i yea ac giao thirc djnh tuyen theo yeu au. So veil
cac giao thirc djnh tuyen theo bang, cac giao thirc djnh tuyen then you au
thuang co tieu de trao d6i thong tin djnh
tuyen
nhO bun. VI voy, ve mat
nguyen tic, cac giao thirc nay a kha nang mer

tong tot
ham d6i v6i ac giao
thirc djnh tuyen theo bang. Tuy nhien, van de Ian nhit ciut cac giao thire
djnh tuyen theo you
au la tre"
do tim kiem tuyen tram khi chuyen tiep th8ng
tin dO. lieu. Vi du ye mOt so giao thirc djnh tuyen theo you
cau glint
giao
thirc djnh tuyen nguin dOng DSR (Dynamic Source Routing), giao thirc
djnh tuyen vector khoitng each theo yeu au AODV (Ad hoc On- demand
Distance Vector routing) vi giao thin djnh tuyen theo thir to tam thai
TORA (Temporally Ordered Routing Algorithm).
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18
DINH TUYEN TRONG MANG MANET
• Cac giao thirc djnh tuyin lai (hybrid) duqc de xuit de ktt hqp uu diem cim 2
logi giao thirc tren va khic phgc cac nhtrqc diem Gila chimg. Thong thuimg,
cac giao thirc lai duqc trien khai trong mpg ci ciu trim phan cap. Cfic giao
thirc dinh tuyen theo bang va theo yeu au duqc trien khai trong cac cap
thich hqp. MOt si vi dv ve giao thirc dinh tuyen lai ghep: giao thirc djnh
tuyen vimg ZRP (Zone Routing Protocol), giao thirc djnh tuyen tong thai
lien
ket dua tren vimg ZHLS (Zone-based Hierarchical Link State routing)
va giao thirc djnh tuyen mmig thy bi'en lai HARP (Hybrid Ad hoc Routing
Protocol), v.v
2.2.4 Ceu Ink vd plain be din &ink 4nk hryin
MOt phuong thirc phan logi khac la dua tren vai tre co the ce cim nut trong ea
che

r
' djnh tuyen. Trong giao thirc dinh tuyen ding 130, tit ca cac nut di (long c6 cling vai
tri va chirc Ming. WRP, DSR, AODV va DSDV la nhftng vi dv v'e djnh tuyen ding 130.
Ck giao thin nay thuting gia djnh ring ciu tnic mpg la phing. Trong mOt giao thfic
djnh tuyen bit ding be, mOt se nut dam nhon vai tr6 quan 19 va eh& nang khk nhau.
Thuat toan phan tan duqc sir dung de km chop dm nut (tic biet nay. Trong mOt so
truing hqp, cac phuong phap djnh tuyen bit ding 130 gin lien v6i ciu trOc mpg phan
clip de de clang t6
chirc vi quail 19 cac nut. Cac giao thirc dinh tuyen bit ding bt) co the
duqc phan chia dip tren
viec to
chirc cac nut di (Jong, chirc Ming dinh tuyen va quart 19
duqc thuc hien nhu the nao. Theo di, cac giao thirc djnh tuyen bit ding 130 trong
MANET duqc chia thanh djnh
tuyan
phan cap theo vimg, dinh
tuyen
phan cap theo
nh6m va djnh tuyen theo nut lei.
Trong cac giao Mire djnh
tuyen
theo Wmg, cac thuit toan
xay
dung Wing khk
nhau duce trien khai cho viec
to
chirc nut; vi dv, mOt so thuat town xay dung vimg sir
dung thong tin vi tri dja 19. Khai thac hien qua vier phan chia wing se giam duqc ding
ke tieu de de duy tri th8ng tin dinh tuyen. Cac nut di dOng trong cimg met Wing biet
dtremg den cac nut khac se co chi phi nh6 han so v6i viec duy tri thong tin dinh tuyen

ten tat
ca cac nut trong Man mpg. MOt
s6
nut hogt (long nhu la gateway va dam
then
truyen thong lien Wing. ZRP va ZHLS la hai giao thin djnh tuyen theo Wing cho
MANET.
Cac giao thirc djnh tuyen theo thorn sir citing thuot Mart xay dung nh6m cho viec
bAu chon truing nhem (cluster-head). Cac nut di dOng duce thorn thanh cac thorn,
Trim Van Tulin-A 14325
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19
DINH TUYEN TRONG MANG MANET
tnrang nh6m d6ng vai trb quan 15
,
thanh vien va dam nh#n chic nang djnh tuyen.
Clusterhead Gateway Switch Routing (CGSR) limOt vi du caa dinh tuyen theo them.
Trong ale giao thirc djnh tuyen theo nut lei, cac not dac biet duqc tv dOng lva
chqn de gip thinh 1 backbone trong mpg. Cac nut "backbone" dam nhk cac vai fro
dac biet, nhu la xay dung va theo dbi dtrimg djnh tuyen, quang ba g6i tin dft lieu.
Core-Extraction Distributed MANET Routing (CEDAR) la min vi du dien hinh cos
lo3i djnh tuyen nay.
2.2.4.1 Khai this cic metric lining cho dinh thy&
Cac metric sir dung cho viec xay dung tuyen duong c6 the duqc sir dung de phan
loci cac giao thirc djnh tuyen trong MANET. GAn nhu mqi giao thirc djnh tuyen cho
MANET sir dung "s6 chking" lam metric. Neu c6 nhieu tuyen duong c6 sin, tuyen nao
ce s6 chking nho nhAt se duqc lva chip. Neu tit
ca
cic lien ket khong day c6 cimg xic
suit I6i thi dtrimg djnh tuyen ngAn se On djnh han dui ng djnh tuyen dai va 0 the giam

tieu de luu lucmg, giant xung dOt gei tin. Tuy nhien, gia (firth ce cimg xac sulk 16i 0
the khong tin tai trong MANET. Theo d6, str On djnh lien ket phai duqc can nhic
trong pha xay clung tuyen &rang. Vi du, Associatively Based Routing (ARB) va
Signal-Based Routing (SSR) duqc de xuAt de sir dung str On djnh lien ket va dO mph
tin hieu nhu 11 mOt metric cho dinh tuyen.
V6i su ph6 bien cita din toan di dOng,
mOt
s6 ung dung di dOng ce the co cac
yeu cAu QoS khac nhau. De dap img cac you cAu nay, cac metric QoS Wang 1mg len
duqc sir dung cho viec djnh tuyen vi chuyin tiep goi tin trong MANET. Giong nhu
mpg c6 day, cic giao thirc dinh tuyen QoS cho MANET ce the sir dung cac metric,
nhu la bang thong, tre, tre jitter, ti le 16i gel tin va chi phi. Vi du, bang thong va dO 6n
dinh lien ket duqc sir dung trong CEDAR lam metric cho viec xay dung tuyen dutmg.
2.2.4.2 iforc luryng topo, dich, vj tri cho djnh tuyen
Trong mOt giao thirc dinh tuyin theo topo cho MANET, cac nut tap hqp thong
tin topo mpg cho viec djnh tuyen. Ngoai cac giao thirc djnh tuyen theo topo, mOt s6
giao thirc djnh tuyen theo dich duqc de xuAt cho MANET. Trong cac giao thirc nay,
mOt nut chi can biet next-hop tren dui ng dinh tuyen khi chuyen tiep gei tin ten dich.
Vi du, DSR la giao thirc dinh tuyen theo topo va AODV, DSDV la giao thirc djnh
tuyen theo dich. Viec sin ce caa he thAng dinh v1 toll) cAu (GPS) ho#c cac he thting
djnh vi ttrcmg ducmg cho phep cac nut di dOng truy nhap thong tin vi tri dia 1S
,
mOt
each
a
clang. Trong cac giao that djnh tuyen theo vi tri, mei quan he ve vi tri gift cac
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DINH TUYEN TRONG MANG MANET

nut chuyen tiep g6i tin va nut dich, ding v6i sir di chuyen cua nut, c6 the duqc sir dung
trong ca quit trinh khiun pha tuyen va chuyen
tier)
goi tin. Location Aided Routing
(LAR) vi Distance Routing Effect Algorithm for Mobility (DREAM) la cac giao thirc
dinh tuyen theo vj tri cho MANET.
Sau day la mOt s6 giao thirc djnh tuyen duqc de xtuit cho MANET.
2.3
Optimized link state routing (OLSR)
OLSR la giao thirc dinh tuyen theo bang va la mOt stir ten tru cim giao thirc tying
thai lien ket c6 dien, hoin toan thich hqp cho mung di dOng MANET. OLSR
tot
thieu
hoa tieu de dinh tuyen bang each chi sir dung cac not duqc chun de" phat trim Ian luu
luqng dieu khien, duqc gui 11 Chuyen
tiep
da diem MPR (Multipoint Relay).
K9
thu$t
nay giam thing ke so lucong you au truyen lui de phat trim lan mOt ban tin tai tft ca cac
not trong mpg.
2.3.1 Bits chpn Multipoint relay
MPR
la de t6i thieu hos overhead khi phat thin Ian ban tin trong mung bang caich
giam Si, lan truyen lui trong ding mOt vimg. Mtn not trong mung lira chqn mOt top hqp
cac not hang x6m
trvc tiep
ciut ne de lam MPR. Hang xOm coa not A ma khong dim
trong tip hqp MPR ciut A c6 the nhOn vi xir ly cac bin tin quing ba nhtmg khong the
truyen cac bin tin quang hi nhon duqc dr

A.
Hinh 23
Qua
trinh phat tran lan bcin tin awing bet
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21
INNH TUYEN TRONG MANG MANET
Mai nut Iva chon tip hqp MPR tir than hang xOm tnrc tiep (one-hop) caa ne.
Tip hqp MPR cua nut A, ki hieu la MPR(A), la tip con caa tip hqp cac hang xOm tnrc
tiep dm A, phai thaa man nhung dieu kien sau: mai nut trong hang xOm hai buec
(two-hop) caa A phai c6 met lien ket trot tiep den MPR(A). Tip hqp MPR cang nh6
thi tieu de luu Wong dieu khien caa giao thirc djnh tuyen cimg nh6. Mai nut phai duy
tri thong tin ve tip hqp hang xOm ma chimg chon lam MPR. T$p hop nay goi la "MPR
selector set" dm mat Ma.
Hinh 2.4 Bdu chpn MPR
Trong OLSR, mOi nut truyen bin tin Hello djnh ky (vi dv met giay mat ban tin)
tren mOi giao dien caa nat. Mvc dick chinh cua ban tin Hello cho phop mai nut ce the
kham pha tuyen tnrc tiep tOi hang x6m caa no. Ban tin Hello dugc quang ba tang
chOng met (hop-by-hop) va phiti Icheng dugc truyen truec do. Ban tin Hello bao gam
ten caa nut khoi too, hang xOm tnrc tiep ma mit khei to truyen ban tin kham pha, va
cac nut ma nut khoi to chon lam MPRs. Khi met nut nghe thAy ban tin Hello, n6 kiem
tra lieu ban tin de ce phii dugc phut sinh tir hang xem mei hay khong, va neu dung,
nut se cop nhOt vao danh such hang x6m ttuc tiep cita nut. Ban tin Hello rid quan tong
trong viec ha trg khai niem MPR. Mai nut kiem tra ban tin Hello thin dugc tir hang
xOm caa ne de xem n6 lieu c6 dugc Iva chon lam MPR cua bit kt hang xOm nao
Musing. Neu vay, nut se phut tan Ian cac c#p nh#t djnh tuyen dugc phut sinh tir cue
hang xOm ma da chon ne la MPR. Mai nut cling c6 the kham phi lieu ck nut c6 la
hang xem hai birec tir ban tin Hello, bei vi danh such ck hang xOm hai bulk dA dugc
liet

ke
trong ban tin Hello dm net hang thin trim tiep cua no. Mai nut Iva chon MPR
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22
DINH TUYEN TRONG MANG MANET
tren cc so hang xem hai bu6c, do vfty mil hang xem hai butc phai nh#n duqc ban tin
MPR.
2.3.2
Truyin bb bin tin
ilidu
Hain topo (Topology control)
Ban tin dieu Ichien topo duqc truyen di voi mvc dich cung cap cho m6i net trong
mang cac th8ng tin lien ket trang thai day de de cho phdp tinh toan duqc tuyen duang.
2.3.3
rink todn tuyIn
Th8ng tin trang thai lien ket dua ra duqc thvc hien thong qua trao d6i djnh ky cac
ban tin, cling giting nhu eau hinh giao dien cea cac not, bang djnh tuyin elm mOi net
co the duce tinh toan.
2.4 Dynamic source routing (DSR)
Giao thee dinh tuyen ngu6n clang DSR la giao tittle dinh tuyen don gian va hieu
qua. Giao thee nay duqc thi'et ke de sir ding trong the MANET v8 tuyen da chting c6
the da di chuyen cao cua cac net. Cac net nay ph6i hqp vdi nhau de chuyen fitly the
goi
tin. Do v#y goi tin co the duce chuyen den cac net khong nom trong vimg phe
sang cea chinh net do. Khi cac net trong mpg di chuyen, tham gia hoc rei khoi mang
thi toan b0 cac the we djnh tuyen duce )(tic dinh va duy tri mat each tv dOng beci giao
thin djnh tuyen DSR.
DSR bao gam 2 cc the cc bitn: Kham pha tuyen (Route Discovery) va Duy tri
tuyen (Route Maintenance). Kham pha tuyen va Duy tri tuyen host dOng horin toan

theo you eau.
2.4.1
Dinh tuyin nguin
DSR phat hien vi sir clang cac tuyen ngu6n. Net
girl tin se phai nom three toan b0
thOng tin ve trinh tv sip xep dm cite elAing (vi tri the nit) cea mang tai mat not dich.
Mtn gel tin duqc djnh tuyEn se mang thong tin ve danh sach cac ching nay trong tieu
de. U'u diem quan tong cart the toe dinh tuyen ngulin la the net trung gian khong an
phat duy tri viec cap nhk thong tin dinh tuyen ;chi chuyen titp cac gel tin bai vi ban
than cac g6i di mang thong tin quytt djnh viec dinh tuyen (danh sach day di cac nit
theo trinh tn ma gai phai di qua).
Viec t$p hop thong tin ve topo mang tai net nguon ciut mot gin cho phep not
ngulin phan phat cac gei tin met each hieu qua trong mang. Dieu nay rat thich hqp vai
viec quan ly tai nguyen trong MANET.
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23
DiNH TUYEN TRONG MANG MANET
Giao thirc djnh thy& dra ten the tuyen ngu6n con c6 them 2 lqi ich. Thir ni t, giao
that c45 the chimg mirth duqc met each don gian tinh Ichong lip yang bei vi tuyen nguian
duqc sir dung dieu Mien djnh tuyen the goi. Thir hai, moi fiver' nguen lit met ban
ke ski
ve
met throng truyen cv the, tin coy de truyen the thong tin qua mang.
DSR sir dung cac thy& nguon vi mOi gei duqc djnh my& dva tren met tuyen nguen
Icharn phi duce, thy nhien nhUng cai thien gAn day deli yen DSR da cho phip hiu het the goi
tin khong phai mang theo phi!
' tieu de chira thong tin diry du ve tuyen nguen.
2.4.2 Khans pith tuyin
Kham pha tuyen duce thvc hien bang.each phat bin Ian yeu cau qua mon de tim

kiem melt tuyen toi dich nit° db. Trong dung don gian nhit, not nguen A muen
kham
pha met tuyen tai nut dich D thi A se phat quang bi goi tin Yeu cAu tuyen RREQ va
goi nay tiep tuc duqc quang ba beri cac not tnmg gian cho den khi no den dirge not
dich D. Trong cu the nay, nhitu t6i tru hos duce sir dung de giOi Nut tin s6
vit phom
vi ctia cite Kham phi tuyen.
Khi met nut S muen girl met goi tin den D, dau tien no se at
vito phisn tieu
de
caa
goi tin d6 met tuyen ngu6n trong de chi ra thb to ciut cac chin ma g6i tin se phiti
di qua. Thong thuang, nut S se dot duet met tuyen nguen thick hop thong qua vies tim
kiem trong Be nha tuyen cita n6 the tuyen di biet fru& day. Tuy nhien nets khong tim
ditty tuyen nao trong
Be
nh6 tuyen, ne se khei to alit tut Tim kitm tuyen dOng de tim
ra met tuyen ngu6n tai D. Trong hiding bp nay to gqi not S la flat nguen con not D la
not dich trong thu tvc Khim pha tuyen.
Trubc khi khei too met g6i tin RREQ, not nguiin chen met nhon clang yeu au
(Request_id) dOt trong g6i tin RREQ. C(Ip <dia chi nut nguen, nhOn clang yeu au> la
duy nhAt.
A
"A"
A
"A, B"
A
"A, B, C"
A
"A, B, C, D"

I id=2 I id=2 I id=2 I id=2
+

+ +

+ +

+ +

+ +

+
A

B

C I >1 D I >1 E I
+

+ +

+ +

+
+

+ + +
I

I


I
V V v v
Ifinh 2.5 Kham phci tuyin trong DSR
Trion Van Tulin-A 14325
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24
DINH TUYEN TRONG MANG MANET
Hilt 2.5
mirth hip qua trinh Kham pha tuyen don gian, nut A co ging khim phi
tuyen tai nut E. De kheri dau Kham phi tuyen, A truyen met tin bao RREQ. M6i tin
bao RREQ than dang not nguan vi dich cita Khim phi tuyen. Nhan don yeu cau
duqc xac djnh boi nut nguen ciut Yeu au. Met RREQ bao gem met ban ghi danh sach
dia chi ctia tong nut trong gian ma tin bao RREQ da di qua. Gil tri ban du ctia ban
ghi tuyen la met danh &etch tong.
Khi met nut nhan duqc ban tin RREQ nay (vi du nhu not B trong vi du), neu
no
la dich ciut Kham phi tuyen, no se giri loi ban tin Tra leri tuyen RREP tai kheri to cita
Kham phi tuyen, chuyen ban copy ciut ban ghi tuyen duqc Ong den tir RREQ; khi
nut
nguon Tilton duqc RREP, n6 cat gift tuyen nay trong Be rifles tuyen
a
sir dung khi girl
cac goi tin tiep theo tai dfch nay.
Mot khic, nett met nut nhon RREQ ma da then duqc met ban tin RREQ khic tir
nut nguen, mang theo nhihtg nhan dong yeu du va dia chi dich giemg nhau hok neu
dia chi rieng cita nut nay da nim trong bao do tuyen dui RREQ, n6 se tir chei You
cau. Neu Ming, nut nay se gin dia chi rieng cita n6 vao ban ghi tuyen trong ban tin
RREQ va tiep tic quang bi net. Trong vi du, nut B se quang ba ban tin RREQ, no se
duqc than 6 nut

C,
nut
C
va nth D ding voy, ne se broadcast Yeu cau, ket qua la copy
dui You du se duqc nhan beri nut E.
Trong viec ban tin RREP ter 10 nut nguen trong the tuc Kham phi tuyen, citing
hon nut E tra liri not A trong hinh 2.5, nut E se kiem tra Be nher tuyen ciut no xem lieu
co met tuyen ngtrqc vat nut A, va neu tim duqc no se sir chmg tuyen nay lam tuyen
nguen de phan phat cac goi tin bao gem ca gel RREP. Neu khong tim duqc met tuyen
nguqc trer 10 A, E co the thuc hien thit tuc Kham phi tuyen tir no tai A. De tranh khit
nang quay loi vo han co the cita dc Khim phi tuyen, no se chen ban tin RREP vao
chinh ban tin RREQ cita n6 del ved nut A. Sir dung co chat nay n6 ding co kha nitng
cOng theo cac goi dO lieu nho khic vi du nhu gei TCP SYN tren met ban tin RREQ.
Nut E con c6 the dao vi tri sip xep ciut cac cheng trong ban ghi tuyen
vi sir
dung tuyen
da dao vi tri nay nhu met tuyen nguen del veri cac gei tin mang ban tin RREP ciut
chinh nO.
Khi kheri too met Kham phi tuyen, nut dang giri se gift loi ban sao ctia pi% tin ban
tau trong be nher dem nOi be (Send Buffer) gqi la bi) dem girl. Ngoai ra Send Buffer
dm chira cac ban sao dut cac goi tin kh8ng truyen di &Km do chua tim ra met tuyen
nguen teri dich. MOi goi trong Send Buffer duchy gan cho met than uteri gian chi ra thin
gian chimg ton tai trong Buffer va goi tin se bj teal be sau khi thin gian luu loi trong
Trein Van Tufin-A 14325
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25
DINH TUYEN TRONG MANG MANET
Send Buffer qua han; de Send Buffer khong bj trim, ki thuOt FIFO hoac ki thujt Wang
ducmg !chic ce the ducat sir ding de truyen cic g6i tin d6 di fru& khi chin het han.
Trong truemg hop gig tin con Itru lot trong Send Buffer ma chua truyen di duqc

thi thinh thoang nut mpg loi thiet lop mai tha We Khitm phi tuyen thy theo dja chi
dich cita cic gel Tuy nhien,
tan
suit khai too cic Kham phi tuyen mdi can phai duqc
giai han do ce the xay ra truing hop dich cita thit ttic khiti too
tuyEn
dif thay va
khong the tai duqc. Tren thvc
ter',
do gi6i han ve phom vi truyen din vo tuyen va sv di
chuyen elm cic nut trong mang nen nhieu khi eau frac mang bi phan manh, nghia la
khong c6 dui tv
sap xep
dm cic chAng ma qua do gOi tin duqc chuyen tiep tai dich.
Kieu phin mitnh nhu voy co the hiem gip hoac phi') Bien thy thuOc vao kieu di chuyen
va mot dO ciut cic nut trong mong.
Trong thaw hqp vii
mai
gOi tin, mOt this tve Kham phi tuyen duqc khai too thi
mOt
so
16n the gOi RREQ khong frau ich duqc truyen tir nut nay tai
tat
ca cic nut khac
trong mang. De giam phan phv trOi tieu de do cic Khiun phi
tuyEn tree ngtr&i
to phai
gidi han tan mat Bei too cic Khim phi tuyen tir mot nth bat ki den cimg mOt dich.
Nat chi duqc phep khai too Khim phi tuyen mai sau khi dqi het khoang then gian
t6i

thieu can thiet de co the thiet Icy thu tvc Kham phi tuyen mai.
Tir ket qua cos viOc kiem tra ban sao the tuyen nguan ghi duqc, thuot toan Khim
phi tuyen dit ngAn chOn duqc viOc cic RREQ trong mong. DO la mOt thuOc tinh
hieu chinh quan tong va lit nguyen nhan too ra
thuOc
tinh khong lip yang cita DSR.
Sir dtmg cic nh(in (long yeu cAu la mOt
tOi uu
don giin khi de cic RREQ ban dill' triti
rung hudng ra phia ngoai so vii not nguOn va rut bat sit the gOi RREQ bao quanh lx)
khai too.
2.4.3 Duy tri tuyin
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DINH TUYEN TRONG MANG MANET

D

E




ROUTE ERROR
ROUTE ERROR a

a ROUTE ERROR

CDD

ACK

ACK
Hinh 2.6 Duy tri tuyin, nat C khong thi chuyin step sir A din E qua
lien kit tea buck nhay slip
theo D cua no
Khi gin hoitc chuyen
tiep mot
geoi tin tai dich D nao d6 su dung tuyen nguon, mai
nut se co nhiem vg giam sat va khing dinh rang goi tin d6 di den duce ch•ng tiep theo
tren tuyen
ngulin
hay chua; gei tin se duqc truyen liti (sau mot sit lin cho phep) cho tai
khi nut nay nhfut duqc khing dinh rang no dA den duqc nut tiep theo. Vi dg truang hqp
duqc minh hqa trong hinh 2.6: nut A girl mOt gei tin tai E sir dung mOt tuyen nguon
th6ng qua the nut trung gian B, C vi D. Trong trubng hqp nay nut A chill trach nhiem
ve viec nhon gei tin a not B, nut B chju trach nhiem viec nhon g6i tin a nut C, nut C Igi
chju trach nhiem ve viec nh#n gei tin a nut D, vi tin nhu the den nut Si cling nut
D phiti chju trach nhiem ve viec nh#n gen tin 6 net E. Trong nhieu twang hqp khing
dinh viec nhOrt gei tin kh8ng inh htemg gi d6i Arai giao thirc DSR do thuc
to
day la
met phAn cua cac thin tuc lap MAC.
Neu ca the nay kh6ng ton tai vi sin co a cac nut thi khi d6 nut gin tin se dimg
mOt bit th8ng tin trong phan tieu de cfia gel tin de you au mOt phtic dip tir
not tiep
theo th6ng qua phAn mem d#c biet trong DSR. Thong thu?Ing phtic dip qua phAn mem
nay duqc truyen
trvc tiep
ten nut girl tin. Tuy nhien neu dubng lien kit gitta hai nut lit

lien kit don htrang thi phitc dip nay co the phai di qua at nhieu chang khic nhau de
quay lai not gin tin
Neu gal tin duqc truyen Igi qua
mOt s6
chOng va vtrqt qua
s
.
0 1A'n cvc
dai cho
phep ma
van
chua nh#n duqc khing dinh tir nut tiep theo, nut nay se gin ban tin brio
16i tuyen RERR quay ter Igi net di gin ban tin ban ditu de xic minh tuyen bi
loi tin nut
nao. Vi dg trong hinh 2.6 tren : neu nut C khong the truyen tin din nut D
tiep
theo, C
se girl ban tin RERR ve nut A va ttr?mg trinh ring tuyen tir C den 13 bi dirt. Khi de A
Than Van Tuan-A 14325
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27