Nghiên cứu một số vấn đề tấn công lớp mạng của mạng tùy biến không dây.PDF

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CHU'ONG I. TONG QUAN YE MANG MANET
1.1. Gifri thieu
Cac thiet bi di dOng nhu cac may tinh xach tay, vbi dac tnmg la cong suit
CPU, b0 nh6 km, dung lin;mg dia hang tram gigabyte, !chi nang am thanh da
phucmg tier' va man hinh man da tr6 nen phO bien trong dbi
song
hang ngay va
trong cong viec. Ding thin, cac yeu cau ket nOi mang de sir dung cac thiet hi di
dOng gia tang din ke, bao
gOm viec
hi trq cac sari phim mong v8 tuyen
dtra tat
v8 tuyen hoac hOng ngoai ngay can nhieu. Vei kieu thiet bi dien toan di dOng
nay, thi gift nhang ngubi sir dung di dung luon mong
muOn
c6 su chia se thong
tin.
Met mang thy bien la met tOp hqp cac thiet hi di dOng hinh thanh nen met
mang tom thin ma {thong
can str
trq &Op cua bit kj
,
sr quart 15
,
top trung hoac cac
dich vu ho trq chuan nao dun:mg co ten mpg dien rOng ma a d6 cac thiet bi di
dOng co the
ket not
duqc. Cac node duqc to do di chuyen va thiet 10p no thy

Sr.
Do
do, topo mang khong day co the thay dOi met each nhanh chong va !thong the du
bao.
Hinh 1.1: M6 hinh mot mgng MANET
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1.2. Ljch sir
Nguyen 1Y lam viec caa mang Adhoc bit
nguOn
tir nrun 1968 khi ck mang
ALOHA
ductc
thvc hien. Tuy the tram lam viec la c6 djnh nhtmg giao thirc
ALOHA da thvc hien viec quern ly truy cap kenh truyen dm% dang phan tan, day la
co sir ly thuyet de phit trien
ky
thuot truy cop kenh phan tan vao mang Adhoc.
Nam 1973
to
chirc DARPA di bit du lam viec tren mang vo tuyen g6i tin
PRnet. Day la mang vo
tuyen
g6i tin da chang
dAu
tien. Trong d6 cic node kip tic
veri nhau de girl dU lieu ten mOt node nim a xa khu vvc
ket not

th6ng qua mOt
node khic. N6 cung cap co the cho viec quern ly hoat Ong tren co sir tap trung va
phan tan.
MOt lqi diem dm lam viec da chang so yeti don ching la
triAn
Thai da chang tho
thuon lqi cho viec dung lai tai nguyen
kenh
truyen ve ca khong gian, thin gian va
giam ning Itging phit can thiet.
Sau d6 co nhieu mang v6 tuyen ea tin phat trim nhtmg cic hg thOng khong
day nay van chin bao gia tai thy ngtrai dung cho den khi chuan 802.11 ra
IEEE di dOi ten mang vo
tuyen
gin tin thanh mang Adhoc.
1.3. irng dyng
Quilt;
Hogt dOng phi tap trung ciut mpg Adhoc va khong phi thuOc vio co
so ha tang mang la mOt yeu
to thiet yeu doi
yeti

vvc quern sv, nhat la trong the
tithing hqp chien

kh6c lief
,
citc
co se ha tang mang bj phi hity. Lk nay mang
Adhoc la Iva chqn s6 mOt de cac thiet bj truyen thong lien lac yen nhau *it each

nhanh chimg.
Truying hpc:
Chung
ta cling co the thiet lap cic mang Adhoc trong true:mg hoc,
lop
hoc,
thu vien, san truing, de ket not the thiet bj di dOng (laptop,
smartphone) lai yeti nhau, giup sinh vien, they co giio c6 the trao dal bai mOt each
nhanh cheong thong qua mang adhoc vira tho.
Gia clink:
Tai nha ban co the tao nhanh mang Adhoc de ket nil the thiet bj di
dOng dm ban yeti nhau, nher d6 ta co the di chuyen ttr do ma van dam him kat not
truyen taidfr
Kit net ccic thiit bj din ni vbi nhau:
Trong nhltng nam ten khi ma cic thiet bj
din tir deu
duqc
gin clic giao
tiep
khong day, glop chting c6 the trao d6i giao
tiap
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voi nhau thi mpg Adhoc se rat phu hqp de tp nen mOt he th6ng thong mirth co
kha flan lien ket yeti nhau.
1.4. Clic d$c dam ctia mang MANET
Thiet bj t r tri dau cu
.
& (Autonomous terminal): trong

MANET, mOi thiet bj di
dOng diu
cuOi
la mOt node tv tri. NO c6 the mang chirc niing cita host va router.
Ben canh kha rang xir 15
,
cc ban ctia mOt host, et node di Ong nay c6 the chuyen
d6i chfre nang nhu met router. Vi vOy thiet bj
du emit
va chuyen mach la khong
the phan biet
ductc
trong mpg MANET.
Hoot &Ong phan tan (Distributed operation):
vi khong c6 he then mpg ha
tang cho ten tam kiem soat hot dung dui mpg nen vied kiem soat va quan
ly
ho#t dOng ciut mang duqc chia cho cac thiet bi dau
cuOi.
Cac
node trong MANET
doi h6i phai c6 sv cong tic yeti nhau. Khi can thiet cac node hog Ong nhu mtjt
relay de thvc hien chat 'tang cita minh. Vi dv nhu djnh
tuyen va
bio mitt.
Dinh tuyen da chtemg (Muftihop):thusia
town di/1h tuyen kh6ng day co ban co
the (filth
tuyen mOt
chong va nhieu ch(ing dva vio the thuOc firth lien ket khac

nhau va giao thlic djnh tuyen. Singlehop MANET den gian hen multihop a van de
cAu
true VI thvc hien vei chi phi thip hen, it ling dung. Khi truyen cac gei dfr
lieu
tir
nguOn
den dich trong phiun vi truyen tai true tiep kh8ng day, cac goi du lieu se
ductc
chuyen tiep qua mOt hok nhieu nut trung gian.
Topo wing dOng (Dynamic network topology): vi
cac node la di dOng nen au
true mpg eel the thay
&it
nhanh va kh8ng biet twee, cac ket not giara cac thiet bi
c6 the thay del theo th&i gian. MANET se thich img tuyen va dieu kien Ian truyen
giOng
nhu nniu di dOng va the node mpg di dOng. Cie node trong mang thiet lop
djnh
tuyen
dung v6i nhau khi chimg di chuyen, hinh thanh mang rieng dui cheng.
Han nita mOt nguari dfing trong MANET co the khong chi hog gong trong mang
ken di dOng d#c biet, ma con c6 the yeu au truy cep vio mpg cong cong nhu
Internet.
Giao dOng ve dung lutmg lien kit (Fluctuating link capacity): ban
chat ti le
Mt
bit cao dui ket not khong day an quan tarn trong mpg MANET. Ket not tir
dau
emit
nay den

du cuOi
kia co the duqc this se qua mot vai ch#ng. Keith giao
tit?
a
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dau cuOi chju
inh hoeing dm nhieu, hieu img da dubng, sg giao thoa, va bang
th8ng clut no it hon so vol mpg co day. Trong mot vai tinh hueing, truy
cep cua
hai nguai dung co the qua nhieu lien ket khong day vi the lien ket nay co the
khong dOng nhAt.
rdi uu hoa cho thiet bf dint mai (light-weight terminals):trong
hAu het cac
twang hgp cac node mpg MANET la thiet bi dau
cu6i vat toe de xir 15
,
curt CPU
thip, b0 nhe it va ltru ter dien nang it. Vi v3y an phai
tOi tru hem cac thuet man va
car
che.
1.5. Kieu kit
ntii
va
chi (10 host dOng
1.5.1. Cic kieu ket not topo mpog
a) Along may cha di Ong
CS

topo nay cac thiet bi chi lien ket voi met may chit duy that, cac thiet bi
lien
kat yen may chit
W tan mit% aware au
Maps
Hinh 1.2: Mang may chn di tong
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b) Mgng c6 cac thiit tn di Jong khong clang nhiit
topo nay cac may co the lien ket
trip tiep yeti
nhau trong pham vi phi song
cua
minh.
S
Hinh 1.3: Mgng cac that obi di Ong khong dung nhiit
1.5.2. Che dq hoat Ong
a)
Chi dO IEEE-Adhoc
the
do nay the node di Ong
truyen
thong true
tiep yea nhau
ma kh8ng an
co so
tang, cac lien
ket !thong thuc hien qua nhieu cheng.
Hinh 1.4: Chi dO

IEEE-Adhoc
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b) Chi do co so. ha king
Che do nay mpg bao gom the diem truy cep AP
c6 djnh va
cac node di dOng
tham gia vao mang, dive hien truyen thong qua the diem truy cep. Cac lien kit có
the thwc hien qua nhieu chAng v the dO My.
Binh 1.5: Chi do hg tang
1.6. Phan loni MANET
1.6.1. Theo giao thin
a)
Single-hop
Mpg MANET djnh
tuyen
Singel-hop 11 logi mpg adhoc don gifin nhAt. Trong
do, tat ca cac node deu nim trong tang met yang pith song, nghin la the node co
the ket not nye tiep yeti nhau ma kung can node Ming gian.Ctic node có the di
chuyen ty do nhtmg chi trong phqm vi nhAt djnh du de the node lien ket trkrc tiep
yeti cac node khic trong mang.
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Hinh 1.6: Giao thee don bribe
b) Multi-hop
Day la me hit ph6 Bien nhat trong mpg MANET, no khic vai mo hinh trate
la cac node co the ket
not

vm cac node Mt trong mang ma co the 'thong can ket
not tnrc tiep
sten nhau. Cie node c6 the djnh tuyen yen cac node khfic thong qua
cac node trung gian trong mang. De mo hinh nay host dOng mot each hoin him thi
can
phai c6 giao thfrc djnh tuyen phu hop vei mo hinh mpg MANET.
Hinh 1.7: Giao thee da bribe
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c)
Mobile Multihop
Me hinh nay cling tuang nr vei mo hinh multi-hop nhung sv khfic biet a day la
mo hinh nay tap trung vao the ling ding co tinh chat thin gian thvc: audio, video.
1.6.2. Theo chile ning
a) Mgng MANET cldng cap (Flat)
Trong kien true nay tit ca the node co vai fro ngang hang yen nhau (peer to
peer) va cac node d6ng vai tr6 nhu cac router dinh tuyen de lieu g6i tren mpg.
Trong nhOmg mpg Ion thi eau true Flat Wang to:Si uu hea viec se ding tai nguyen
bring thong dm mpg vi rilang tin dieu khien phai truyen tren toitn be mpg. N6
thich hqp yen nhemg topo co the node di chuyen nhieu.
b)
Mgng MANET pluin cap (Hierarchical)
Day la mo hinh sir dgng phi) bien 'that. Trong mo hinh nay thi mang chia
thimh cac domain, trong mei domain bao gem met ho4c nhieu cluster mei cluster
Chia thanh nhieu node. CO hai logi node lit master node va normal node.
Master node 11 node quitn trj co nhiem vu truyen du lieu dm the node trong
ding cluster den cac node trong cluster khic va ngugc Igi, not each khic no nhu
met gateway.
Normal node la cac node nam trong cling met cluster. NO co the kat nOi yeti

cac node trong cluster hoac ket Wri cluster lchfic thong qua Master node.
Vei cac co the tren, mpg sir dung tai nguyen bang thong hieu qui bon vi cac
tin Stan chi phai truyen trong met cluster. Tuy nhien vier quan 15
,
firth chuyen
deng cua cac node tre n'en phirc tap hon. Kien true m(mg phan cap thich hqp cho
cac mang co firth chuyen deng thip.
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Hinh 1.8: Mang MANET phan cap
c) Mang MANET kit hqp (Aggregate)
m6 hinh nay met mang gem nhieu Wing (zone), met Wing
g6m
nhieu node.
M8i node bao
gOm
hai mix topo: topo mac thitp (node level), va topo mat cao
(zone level).MOi node dic trung bin: node
ID
va zone ID. Trong met zone c6 the
tip dung kien true ding cap hoc phan cep.
Hinh 1.9: Mang MANET kit hqp
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1.7. Wet lu#n
Chuang nay cung cap nhOng kien thic
tong quan ye
ming thy bien adhoc not

chung vi ming MANET not rieng, tir cac doe diem, cite kieu ket not
Ara the dO
hog clOng, phan !oil dira UM
' mOt set giao thfrc vi chire nitng lam ca so cho cac
nOi dung trong chuang sau.
CHIJONG II. DJNHTUYEN VA CAC DE DQA BAO MAT
TRONG MANET
2.1. Viin de djnh
tuyen trong
mting MANET
2.1.1. Cac think toin djnh tuyen truyen thOng
Cie giao thus djnh
tuyen truyen
thing sir ding hai giiti thuot:
•
Distance Vector:
RIP, IGRP,
Nguyen tic hog dOng: mr3i router se giri bang djnh tuyen cis minh cho
tat
ca cac router dirge not trite
tiep
veri no. Cie router de so sanh yeti bang djnh
tuyen ma minh hien co va Iciem tra Iai cac tuyen duemg dm mirth veti cac tuyen
duang meri diem dirge,
tuyen
duong nao
tei
tm han se dirge dim vao bang djnh
tuyen.
Cie goi tin cap nhit se dirge giri theo djnh IcS

,
(30 gitly yeti RIP ,90 giay
cleti yeti IGRP)
UV diem:
a
ciu hinh, router khong phiti xir 15
,
nhieu nen khong
Mn
nhieu dung lircmg130 nher WI CPU co
hie do xit ly
nhanh han.
Nhugc diem: he thong metric qua don glen (nhu Rip chi la hop-count )
din den vier cac tuyen dtrimg dirge chgn vao bang dinh
tuyen
chtra phai
tuyen
duang tot nhit.Vi cac gig tin cep nhit dirge girl theo dinh 16
,
nen
met lugng Wing th8ng ding ke se IA chiem. Do router hOi tit chum, din
den vise sai lech trong bang din!'
tuyen gay nen
hien tugng yang lOp
(loop).
•
Link State:
OSPF, IS-IS
Nguyen tic hoot dOng: cac router khong gin bang djnh tuyen ciut minh, ma
chi giri tinh trong ctia cac dyeing lien ket trong ca sir dir lieu trong thii lien ket

(linkstate-database) dm minh di cho eke router khac, cac router se ap dung giiti
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thuat SPF, to xay dung bang (firth tuyen rieng cho minh. Khi mpg a hiji
At, the giao thirc Link state g kh8ng giri 4p nhat djnh IcY ma chi giri khi nao
6 su thay d6i trong mpg (1 dubng bj down , can six dung throng du phi:mg).
Uu diem: co the thich nghi duqc yeti da so hg th6ng, cho phep nguiri
thiet ke co the thiet ke mang Iinh host, phial Ong nhanh v6i tinh huOng
xay ra.Do khOng giri cap nhat djnh Icy nhu Distance Vector, nen Link
State blo dam duce bang thong cho the duCmg mang.
Nhtrqc diem:do router phai xir ly nhieu, nen chiem nhieu b0 nha, t6c dO
CPU cham hcm nen tang dO tre.Viec sir dung cac giao thirc djnh tuyen
truyen thOng trong mang MANET se din den rat nhieu van de fro ngai
can gnu quyet.
✓
Tieu ten nang luqng nguen nuoi cho the cap nhap djnh IcY nhu trong
giao thirc djnh tuyen Distance Vector.
✓
Tieu ton bang thong mang cho cac cap nhap dinh
✓
Lam qua tai b0 vi xir ly elm thiet bj: khi the th8ng tin cap nhat, so
node mpg tang len.
✓
To ra nhieu dtrang di du thira.
2.1.2. Cu yeu cau chinh dig vai viec djnb twin trong mung MANET
Cac giao thirc djnh tuyen trong mang MANET an dam bao:
•
Thich ang nhanh khi topo »King thay


khi the node mang di chuyen
nhanh, yeu cau ket n6i tang len thi the giao thirc host diang theo ca cha
t
tiep
can top trong se giam hieu qua r6 rut do phai Mn nhieu thei gian de thu thop
thong tin ye trang thin hien tai va phat tan Iii n6. Trong khi
do
cAu hinh
mang co the di thay d6i khac di risi.
•
Dam bao hieu qucitrong mai trufmg truyen khi cac node clang yen: lac nay
topo mpg IA c6 djnh kh6ng thay d6i nen the giao thirc djnh tuytm chi can

giri cac cap nhat khi co yeu cliu hoik mang thay dOi nhu viec miat node nao
de tit ket nei.
•
Khong có lap dinh

can ngan chan hien tucmg nay, bai vi khi do the
goi tin bj djnh tuyen sai, din den viec hi truyen quay wing lien tuc trong
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mot so ket nal mang, kb& cho bang thong mang va cac tai nguyen !chic
nhu nthg Krung nguan nu8i bj tieu tan vet ich.
• Bdo men: viec
djnh tuyen trong mpg MANET co nguy ca bj tan ding
a
ding bang cac phuang phap nhu xam nh(ip dubng truyen, phitt lai, thay dai
cac gai tin tieu de, dieu hut:mg the thong diep djnh

tuyen.
Do do khi thiet ke
cac giao that djnh
tuyen
can phai co phtumg phip phit hien dirge vi
ngan than cac lo3i ten cong.
2.1.3. Plan lospi the
kg
Mutt djnh tuyen
a) Link state vin Distance vector
Thucit tocin djnh twin vector khocing
cach(distance-vector routing protocols)
Thujt total nay dung thuat tom Bellman-Ford, trong do chi djnh mot
con
se,
gqi la chi phi (hay trung s6), cho mai mot lien ket gith cac node
trong mang. Cac node se girl thong tin ve dubng di tir diem A den diem
B qua the duang truyen (ket n6i) mang Iii tang chi phi thip nhit (la
tang cac chi phi ctia cac ket nai gift the node dirge dung).
Thuat tofu' hoot don veri nheng himh dthg rat dun gem. Khi mot node
lcheri dOng Ian
du,
no chi biet the node ke Uwe tiep yeti no, vi chi phi
true
tiep
de di den do (thong tin gam: dank sach cue the dich,
tong
chi
phi den tang dich va buck ke tiep de girt de lieu den do to nen bang
djnh tuyen, hay bang khoing each). Mai node, trong mot tien trinh, girl

den tirng "hang xem"
ding
chi phi dm no de di den cac dich ma no biet.
Cac nodehang x6m phan tich thong tin My, va so sanh veri nhemg thong
tin ma chimg dang "biet"; bat IcY dieu gi cal thin doge nhang thong tin
cluingdang co se dirge due vao cac bang djnh tuyen cue nhimg hang
xem nay. Den khi ket dine, tat ca node tren mpg se tim ra buerc truyen
ke tiep
nit
tru den tat ca mui dich, va
tong
chi phi
tin
nhat.
Khi mot trong the node gap van de, Meng node !chic co sir dung node
hong nay trong 10 trinh cita mink se loci be nheng 10 trinh de, va to nen
thong tin men dm bang
djnh tuyen.
Sau do cluing chuyen thong tin nay
den
tat
ca nut gait ke va lap lid qui frith tren. Cu& ding,
tat ca
node tren
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mang !thin duqc thong tin cop Mit, va sau do se tim throng di m&i den
tit ca cac dich ma thong con toi duce.
tocin clinh tuyin trong thcii kit

ndaink-state routing protocols)
Khi ap dung cac thu3t town trang thai ket noi
,
mOi node sir dung dia lieu
ca sot ciut no nhu la mOt ban dO cim mpg yeti Bang melt do thi. De lam
dieu
nay, mOi
node phat di tai toim mpg nhimg th8ng tin ve cac node
khac ma n6 c6 the ket noi duqc, va tirng node g6p thong tin mOt each
doc lip vio bitn di). Sir dung ban
a
nay, mOi node sau do se xac djnh
duqc tuyen duang tot nhit tir no den mqi nut khac.
Thuit town di lam theo each nay la Dijkstra, bing each xay dung
eau
true
du
lieu khac, clang cay, trong d6 nodehien tai la gee, va chira mqi
node khitc trong mang. Bit
du
veri min
cay ban
Mu
chi chira chinh no.
Sau do Ian Itrqt tir tip cac node chua dirge them vlo cay, no se them
node co chi phi thip nhit den met node di co tren cay. Tiep tuc qui
trinh den khi mqi node deu duqc them vito cay.
City nay sau d6 plum At de xay dung bang djnh tuyen, dua ra buck
truyen ke tiep tot tru, de tir met node den bit kj
,

node khic tren
mang.
So sank cac thudt town dinh tuyin
Cfic giao thirc djnh
tuyen
theo thuit tom vector khofing each don glen
va hieu qua han trong cite mang nh6, doi hoi it (neu co) sir giam sat.
Tuy nhien nhuqc diem dm no la kha ring hei to chim khi mang Ian va
thay doi, dieu nay clan den sir phit trien cua cac thujt toan trang thai ket
noi tuy phirc tap han nhung Mt han de dung trong cac mang len.
U'u diem chinh cua djnh
tuyen
bing trang thai ket nOi la phan img nhanh
nhay han, va trong met Ichofing thin gian co han, di yeti sir thay din ket
Ngoai ra, nhung &Si doge giri qua mang trong djnh tuyen bing
trang thai ket nOi thi nho han nhang g6i dung trong djnh tuyen bang
vector. Dinh tuyen bang vector doi hei bang djnh tuyen diy do phai
dirge truyen di, trong khi djnh
tuyen
bang trang thai kat mil thi chi co
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thong tin ve hang x6m cita node duqc truyen di. Vi v(iy, cic gal nay
dimg tai nguyen mango mirc kh8ng ding ke. Khuyet diem chinh ciut
djnh tuyen bang trong thai ket noi la no doi hoi nhieu sv luu frit va tinh
toin de chay han dinh tuyen bang vector.
b)
Dinh tuyin phan zing va din!r twin cha ring
Cic giao thirc djnh tuyen trong mpg MANET duqc phan chia thank the

loii: djnh tuyen chit ling (proactive), dinh tuyen phin img (reactive) va djnh
tuyen lai ghep gifts hai logi att. Cic giao thac djnh tuyen chit ling sir dung
phuang phip phit tin (floading) de quing bi thong tin toi ck thiet bj. Phuang
phip nay cho phep thai gian thiet lap &rang nhanh dra tret
' the tham so girl tea
thiet bj sin sang cho ket noi. Tuy nhien, phuang phip nay cling lam luu luvrng
cic g6i tin tim duang tang
len
rat len, day chinh 11 nhtrqc diem clia phuang
phap nay. Giao thirc djnh tuyen hung thai lien ket toi tru OLSR va giao thirc
djnh tuyen vector khofing each tan ty dich DSDV la hai vi du cilia giao thirc
dinh tuyen chit (mg.
Ck giao thirc djnh tuyen phim img thiet lop tuyen dip theo tang y'eu cau
ket noi. Phucmg phip nay han the duqc chi phi tim duang, nhtmg nhtrqc diem
ca ban la gay tre Ion cho cic khung truyen din dau tien cling Mut thai gian
*al &rang din ch(im. Hai giao thirc phin ting dien hinh la giao thirc dinh
tuyen vector khoing each theo you eau AODV vi giao thirc djnh tuyen nguOn
dOng DSR.
MOt khi xiy ra lei tai node, the giao thirc djnh tuyen thuang khoi phuc
&rang den bang phuang phip thiet lop tuyen moi. HAu het cac tiep
can
hien
nay deu sir dung thong tin phin hoi tai thiet bi ngulin nhim kheri tao tuyen mei,
vi v#y km ltrong bin tin trao dOi la rat 16fn vi tang len rat nhanh khi kich thuot
mang 16n, nhat la dOi veri cic giao thirc djnh tuyen chit img. Khi kich thuoc
ming tang cling ding nghia Arai sir suy giim hieu Wing mang do hien tuving tre
cos thit tyc djnh tuyen vi truyen khung diu tien hing len rat Ion neu sir dung
giao thirc (firth tuyen phin img.
c)
Dinh tuyin ngutin va dinh tuyin theo chdfb wag

Voi
djnh tuyen ngu6n, tan be, thong tin ve duang di teri dich duqc dOt
trong twang tieu de dm gai tin de lieu, cic node trung gian chi vie chuyen
21
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tiep gait tin theo dtrerng trong tieu de. Lqi diem cria giao thire nay la lotti be)
duqc nhu cau quitng ba dueng dinh ky vit the gal tin kham pha (discovery)
hang x6m.
Trong dinh tuyen theo chn, khi mgt node than duce g6i tin can chuyen
tai dich, node do chuyen
tiep
gen tin theo chAng
tiep
theo huOng tai dich ma no
hitt. Node tiep theo lai chuyen tiep goi tin den dich theo nht
-
mg chang ma no
biet dva vao bang dinh tuyen tha no. Qua trinh tren se dimg lai khi gen tin
duqc chuyen tai dich. Nhtrqc diem ciia phtumg phip nay la
tat
ca cac node can
duy tri thong tin dinh
tuyen nen
phai xir ly nhieu ham va co kha nang tao thanh
cfic yang lap dinh
tuyen.
2.2. Cac giao that dinh tuyen chinh trong ming MANET
MANET ROUTING PROTOCOL
Hinh 2.1: Ccic giao thtic dinh tuyin

trong
MANET
2.2.1. Giao tharcdinh tuyenDSDV
DSDV (Destination-Sequenced Distance-Vector Routing) la
giao dilly chi' (mg
dva tren dkra tren thujt torin Distance vector duqc xay dung beri C.Perkins
vaP.Bhagwat nAm 1994. Giao thirc nay &gm xay dvng dva tren tieu chi giit
nguyen stir don gian ciut giiti thu3t
Bellman-Ford vit
loai be van de yang 1Itp.
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Truyn thong tin djnh tuyin:
Thong tin djnh tuyen duqc girl quang be
(broadcast)
us tat
ca the node hang xem lien ke no. Thong tin cap nlf(it duqc phat
dinh ky hoc ngay khi co cac thay dii xay ra trong mong. De birth l#p djnh
tuyen
DSDV gon
s6 thu
to chin cho moi duting. SO thin to duqc On ben node dich, duqc
girl di trong g6i tin cap nh#p. SO thin
tv
nay cho they de mei dm min dueing,
duong nao co
so
thu tv cao ham duqc xem la

tot
ham.
Hinh 2.2: Dinh tuyin trong DSDV
SO tht tv nay se tang len met don vi khi met nodephat hien duang di taxi dich
co lien ket bi hong khi no khong nh(in duqc cep nh#t djnh kY. Khi ay trong g6i tin
cop nh#t
ke tiep
no giri di se quang ba clueing ten dich nay co
s6
ch#rtg bang ve hen
(metric — co) va tang thfr tv clueing.
Khi met node nh#n duqc th6ng tin mei ve met
tuyen
clueing, tuyen nay se
-
duce chqn
neu
no co so thu tkr Ion ham cac so thir tier khac eta ding tuyen de trong
bang djnh tuyen. Neu no co
cling s6
tht tv thi no se duqc chqn
neu
co so metric
tot
ham.
De lam giam kich thute gel tin cap nhjp, DSDV sir dung hai loM th6ng dip
cop nhOt le:
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Full dump:
cip nhit
day du.
Thong diep nay bao gem than be thong tin
dinh tuyen ma node do biet den than diem de.
Incremental dump:
c#p nhit boi sung. G6i thong diep nay chi bao gem
cic thong tin ve nhOng thay doi tir fan cap nhit day de gin Milk
Hai foci thong diep cot nhit nay thrqc Iuu vho hai bang khic nhau, mett
bang de chuyen
tiep cac
gtii tin day du, met de phitt cac goi tin cap nhit.
G6i tin 4p nhit dhy de chi dirge phit thuong xuy'en khi cac node
thu&ng xuyen di chuyen, khi mang it thay dei, che yeu chi co goi tin 4p
nhit be sung dirge giri di.
2.2.2.
Giao thircdinh tuyenOLSR
OLSR (Optimized Link State Routing Protocol)
lit giao thin chti frog (Iva tren
thuit tom tang thai ket not (Link state). Cic node giri dinh lcjr ra toim mang thong
diep "Hello" de trao dei thong tin ve hang xem. Thong tin nay bao gam IP dm
node,
se
thr hr vi danh sach cac thong tin khoing each cue cac node hang x6m.
Sau khi cop nhit !Mang thong tin nay node se illy dvng len bang djnh tuyen
cue
no vi c6 cal !thin ten the ve tom mpg. Dva vim bang djnh
tuyen
nay no c6 the
tv tinh dirge dubng di teti folic node khic dva vio thu#t tofin tim duerng di ngin

nhat. Khi met node nhin dirge met goi tin trimg 1#p yeti
ding s6 thin tit
no se loci
be g6i tin My. Trong bang dinh tuyen node luu tilting tin djnh tuyen teri tit ca
cac node khic trong mang. Meng thong tin nay chi dirge cip nhit khi:
Khi node nh#n thity sv thay doi trong quan he' hang xom (vd: mat lien ket
den node hang x6m, )
Tuy'en dubng teri cac node dich khic het hen (qui lau khong
dirge
cip nhop)
Phfit hien ra dubng di mei ngin hen de teri dich.
Diem khic biet gifts OLSR vi LSR II viec giao thtic OLSR host dung dva ten
'
viec met !them node mang cling tic v6i nhau tao nun *it kip phat chuyen tiep da
diem MPR. Mai node N trong mpg se Iva chip ra met tip cac node hang xem
cue
no vio kip da diem MPR(N), cac node thuOc kip da diem nay se chuyen
tiep
cac g6i tin dieu !Nen (lucre giri to N. Node kh8ng thuOc kip da diem cue N van xir
15r gel tin nay nhtmg se kluing chuyen
tiep den
the node khic.
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Hinh 2.3: Quy trinh chuyin dap goi tin see dung MPR
Liu diem du tien caa viec sir dung kip da diem la viec lam giam thieu cac thong
dip quang ba phat tin trong raging, glop cho bAng th8ng duqc cai thin dang ke.
Lqi diem thir hai la viec giam duqc kich thuk cua g6i tin "Hello" vi no chi Itru tni
cac thong tin lien quan ten cac node trong kip da diem dm n6.

Hinh 2.4:OLSR ngiln chin vong kip bang see clung MPR
2.2.3. Giao thircdinh tuyenA0DV
AODV (Ad Hoc On-Demand Distance Vector) lit giao thirc dkra tren thuAt toan
vector khoang each. AODV
ten
thieu holt se ban tin quang bfi an thiet bang ckh
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to ra cac tuyen ten
co
so theo you au, ngtrgc yeti viOc duy tri mOt dank sich
hoin chinh cac tuyen nhu thuot town DSDV.
Node
oral,
Node
dich

(apt du twin

Node
nsubn
Node
dich
(b)CIp
ins II/yen
Hinh 2.5: Qua trinh khbm phb tuyin trong AODV
Khi mOt node nguan muOn gai mOt bin tin den mOt node dich nio d6 vi kheng
biet rang di co
met tuyen

ding den dich do, no phii khai
dAu met
qui trinh Ichim
phi throng truyen. N6 phit quing bi mOt gel y8u au
tuyen
(RREQ) den cac node
Mn con. Cie node Mn con nay sau do se chuyen tiep gai you
cAu
den node lin con
khic ctia chimg. Qua trinh ca tiep Ate nhu voy cho den khi co mOt node sing gian
nio 46 xic djnh dugc
met tuyen "di, tuoi" de
dat den dich. AODV sir dung so thir
to dich de dim bio rang tit ca cac tuyen kitting lip va chira hiu het thong tin tuyen
hiOn tai. Mai node duy tri so Sin tir cia no cling yeti mOt ID quing bb. ID quing
bi dirge ting len mai khi node
khai du met
RREQ, vi cling yeti dja chi IP cia
node, xic djnh duy nhAt mOt RREQ. Cling vii so tuAn
to
vi ID quing bi, node
nguiin bao gam trong RREQ hAu
het so tan to hien tai
cia dich ma no co. Cic
node trung gian co the tri 16i RREQ chi khi nio ching co mOt tuyen den dich ma
so tuin to dich Wang ling Ian hon hooc bang
so twin to
chits trong RREQ.
Thong snot qui trinh chuyen
tiep RREQ, die node trung

gian ghi vio Bing
djnh
tuyen
cia ching dja chi cis cac
node lin con
tir khi nhAn duqc bin sao
dAu
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Phan Trung Nghia
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tien cua g6i quing bi, theo do thiet I3p dirge met duimg din theo Mai gian. Neu
cac ban sao cim cimg met RREQ dirge nhon sau d6, cac goi nay se bj hu9 be. MOt
khi RREQ di dot den dich hay mot node thing gian yeti
tuyen "du
tuai", node dich
(hoic node trung gian) dip an Iai bang each phit dart phucmg met gel dip Ling
tuyen (RREP) ngtrqc ve node lan cjn ma tir do no thu dirge RREQ. Khi RREP
dirge djnh
tuyen
nguqc theo &rang din, the node bra dubng din do thiet lop the
thuc the
tuyen
chuyen
tiep
trong Bing djnh tuyen cim chi node ma no nh#n dirge
RREP. Cic thuc the
tuyen
chuyen
tiep nay
chi thj

tuyen
chuyen
tiep
tich cue.
Can vii mOi thqc the
tuyen la mot
b0 djnh
than
tuyen co nhiem vu xoi cac dap
the
neu
no Ichong dirge sir dung trong met died ban xic djnh. Do met RREP
chuyen flap tren dtrang din dirge thiet Iftp bai met RREQ nen AODV chi ho trq
viec sir dung throng truyen doi ximg.
Trong AODV, cac tuyen duct duy tri dieu kien nhu sau: Neu met node nguen
chuyen ding, no phii khoi Ong lai giao thus }chain phi
tuyen
de" tim ra mot tuyen
mai den dich. Neu met node tren
tuyen
chuyen ding, node lin c#n luting len cim
no cho 5/ den chuyen Ong d6 va truyen met bin tin "Khai bio str co dwang thong"
(met RREP khOng xic djnh) den
mil
node lin ejn tich cue Meng len de thong bio
cho cac node nay xoa phin
tuyen
d6. Cic node nay thqc chit truyen met "Thong
bio sur c6 duang thong" den cac node Ian can luting len. Qua trinh cir tiep turc nhu
v#y cho den khi dat den node

ngulin.
Node
nguOn
sau d6 co the chop khai ding lai
met qui trinh khim phi
tuyen
cho dich d6
neu mot tuyen yin can
thiet.
Ngoii ra, giao thirc nay sir dung bin tin HELLO dirge phit quing bi djnh ky
be' met node de thong bio cho tit ca cac node khic va nhOng node Ian c#n cua no.
Ck bin tin HELLO co the dirge sir dung de duy tri khi MIT kit n6i cue b0
cua
met node. Tuy nhien, viec sir dung bin tin HELLO la khong can thiet. Cic node
ling nghe viec truyen Iai g6i du lieu de dim bio
ring yin dat den chOng ke tiep.
Neu kh8ng nghe dirge viec truyen lai nhu the, node co the sir dung met
trong so
cac ky thuot, ke ca
viec tiep
nlitin bin tin HELLO. Cic bin tin HELLO co the lief
ke cac node khic ma t(r do node di ding di nghe tin No, do
do
to ra khi ning
lien
kit Ion han cho mpg.
27
Node
^lobs"
Node

tech
Node
nsubn
Node
did,

(e) key dims bang en wean

4C-Cr
i.er
si•
lb) Troyer, dip &nu tuytn vol bang ghi tuytn
Phan Trong Nghia
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2.2.4. Giao thircdinh tuyenDSR
Giao thfrc DSR (Dynamic Source Routing) li met giao thfrc dinh tuyen phin
Ang tir node ngwin.
Trong d6, ctic node di dOng can duy tri b0 nher dem ve tuyen
chfra the node
nguiin
ma node di dOng nhon biet duktc. Cic thqc the trong b0 nhet
dem ve
tuyen
dtrqc cop nh$t lien tuc.
Hinh 2.6: Giao thec DSR
Giao thfrc nay bao Om 2 giai clop chinh: a) Khim phi tuyen va b) Duy tri
tuyen. Khi met node di dOng gars met goi den met node dich nio do, tit& het no
phai tham vin bki nher dem
tuyen de
xic dinh 1a no dA co met

tuyen
de" den dich
chua. Neu no co met tuyen chua het hieu lye de den dich, no se sir dung
tuyen
nay
de giri goi di. Trii lai,
neu
khong co mot tuyen nhu the, no phii khiti
Mu met
qui
trinh khim phi
tuyen
bang rich phit qtuing bit mot g6i you cAu tuyen. Bin tin you
cliu nay chfra ilia chi dich, ding yeti dig' chi node ngutin vi
56
nhOn clang duy nhOt.
MOi node nhOn duqc goi nay se tien hinh kiem tra la no co biet met tuyen nao
de
den dich kh8ng. Neu khong, no them rho chi cua no vao Bing ghi dinh
tuyen
cua
gOi vi sau d6 chuyen
tiep
g6i teen cic than truyen ng8 ra. De gioi han so
yeu au
tuyen phit tren
cic duong truyen nge ra cua node, met node chi chuyen
tiep
yen
au tuyen

neu no chua biet yeu
au
d6 vi neu dist chi cos node di dOng chua xuitt
hien trong Bing ghi tuyen. MOt dip
(mg tuyen
duqc to ra khi hooc la yeu
cau
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tuyen dot den dich hoc la khi no dot den met node trung gian chira trong Ix) nha
dem tuyen cua n6 mot tuyen den dich chua het hieu loc. Den hie gel co the dot den
dich hay den mot node trong gian nhu the, no chfra mot Bang ghi tuyen cho biet se)
titan ty ching dfi UM qua.
Neu node too ra dfip ling tuyen la dich dil no dAt Bang ghi tuyen chin trong
yeu cAu tuyen vio dap ling tuyen. Neu node Wang ling la melt node trung gian, no
gin them tuyen trong b0 nhe dem dm no vito Bing ghi tuyen va sau do to ra mot
dap ling tuyen. De tra ve dap ling tuyen, node tacmg ling phai co mot tuyen de
khai dAu. Neu n6 co mot tuyen de khai dau trong b0 nha dem tuyen cua no, no co
the sir dtmg tuyen do. Trai lei, neu cac throng truyen doi ximg dirge ho fro, node
co the khei dAu mot qua trinh kham phi tuyen cua no va tiep We gni di dip ling
tuyen tren mot yeu cau tuyen mei.
Viec duy tri tuyen dirge hotin thimh thong qua sir ding cac gen kli tuyen
(RERR) vi cac ban tin xfic nhon. Cfic gel 18i tuyen doge to ra a mot node khi lap
lien
ket dfr lieu g0p so c6 diking truyen. Node nguan luon Won bj climg khi mot
tuyen bj cat dirt (co mot lien ket tren tuyen bj 16i). Khi nhfin dirge min gei ISi
tuyen, ching bj loi se bj loai bo khoi b0 nha dem tuyen cua node va tat ca cac
tuyen chin citing nay deu bj cat a diem d6. Ngoiti cac ban tin loi tuyen, cac ban
tin xic nh(in dirge sir ding de xic mink so hoot dOng chinh xfic cua cac direng

thong tuyen. Cac bfin tin xic nhin nlur the bao gOm ca xfic nhon thy dOng (khi
node di dOng co the nghe vier chuyen tiep goi a chang ke tiep tren tuyen).
2.2.5.
Giao thircitinh toyenTORA
TORA (Temporally Ordered Routing Algorithm) la melt thuit town djnh tuyen
phfin bto khong co vong leP va do thich nghi cao, dua tren khai niem dfio ngugc
dtrong thong. TORA dirge de xuAt cho moi trutmg not mang co tinh linh dOng cao.
N6 la mot giao thfrc khei phat tfr nguOn va cung cap da tuyen cho moi cfip node
nguen/dich an thiet. Nguyen 15
,
chit dgo trong TORA la djnh vi cac ban tin dieu
khien deti vei moi ttip hop cac node gait yeti nai xfiy ra so thay del topo mpg. De
thoc hien dirge dieu nay, cac node can duy tri thong tin djnh tuyen ve de node ke
Om (chi mot ch(ing). Giao that nay thoc hien 3 chile 'tang co ban: Tgo tuyen, Duy
tri
tuyen, vi Xofi tuyen.
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Trong
suet
giai (loan too ra vi duy tri
tuyen,
cac node sir Ong mot tham so "do
cao" thiet 13p met DAG (so des birth xo&n 6c) co
g6c
a
node dich. Sau d6, the
duerng truyen
dirge

chi dinh mot huemg (luting len hay
lining xueng)
dtra tren tham
so do cao twang del
cis cac node lin con. Qua trinh thiet 13p DAG twang tv nhu
qui trinh van tin/dip Ong trong LMR.
Trong then gian met node di chuyen, tuyen DAG In phi va va vi3c duy tri
tuyen
can
de thiet 13p lei mgt DAG co
gee
6 cling dich do. Khi duetng th8ng luting
xuOng cue;
cling bi sir co thi mot node to ra mot mirc tham chieu meri dtra vio
mire tham chieu cim cac node lin con, phtii hqp hoot dOng co hi3u qul de phin
ling loi sir co d6 mot each co clu true. Cic dubng th8ng dirge dio ngugc de phin
anh nhcmg thay doi trong vi3c thich nghi yeti mire tham chieu med. Viet nay co
hi3u qui giOng nhu sir dtio huerng cia mot hay nhieu dubng th8ng khi met node
khong co cac dutmg thong
!ding xueng. Vigo
dinh than la met you
t6 quan tong
deli yeti
TORA do tham so "do cao" dOc 13p vol theri gian sir co dubng thong;
TORA gii sir ring tit ca cac node deu co (king h6 deng b0 (thvc thi qua men
nguen thbi gian ben ngoii nhu
he
thtmg dinh vi town ciu - GPS).
Clic tham
so

ctia TORA
gem:
Thai gian sir co duang thong,ID duy nhit cis
node xic dinh mitt tham chieu maxi, Bit chi an phim firth, Tham s6 this tit truyen,
va ID duy 'that cia node. Tham so this 3 the hien mire tham chieu met each co
chop lqc. MOt mist tham chieu man doge xic dinh
m8i
khi mitt node khong con
dtremg th8ng
luting xming cu6i
cling do mr ce dui:mg thong. Giai down xoa tuyen
cua
TORA bao gem mot bin tin quing bi
"Xoa tuyen"
(CLR) trong toan mang de
xoa cac tuyen kh8ng con hi3u lire
Trong TORA co met str bien dong tiem tang xay ra, d3c bi3t kin nhieu top hop
cac node dang lien ket Ia phin hien dang bi xoa,
cac tuyen
dang xoa, va cac tuyen
dang xay dung man. Do TORA sir ding tea dO lien node nen bai toin bit can bang
dm no twang tir nhu bai loan tinh den v8 cling trong cac giao thisc dinh
tuyen
theo
vector cis ly, ngotti trir cac hien dOng 11 tom then vi sir her tv tuyen cutti cling van
dot dirge.
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2.3. Cic

moil
de dna ban nt.t trong ming MANET
2.3.1.
Wong quan
Voi str tang nhanh ciut cic thiet IA di dOng re han, nho han, vit manh me han,
mang MANET fro thanh mot trong cac mang duqc quan tam nghien ciru. Day la
kieu mpg
tit t6
chit mei ket hqp lien ket khong day veri node di dOng mot dO cao.
Khong
&Ong nhu cac
mpg c6 day thong darting, chimg kh8ng c6
ha tang co djnh
(cac tram ca so, cac diem quin li trung tam). Cic node hqp veri nhau thanh mot
topo thay
dei tuy y. Sr filth host nay
khien chimg duce quan tam cho mot so ling
ding, nhu cac ling dung trong gam str nai topo mang c6 the thay doi nhanh de
phan inh cic di chuyen hoot dOng ciut mot lye ltrqng, vit cic hoot dOng eau non
nai ma cic mang ha tang
có dinh
c6 the khOng hoot dung. Mang thy bien to to
chic cling thich hqp cho cac hei nghi trice tuyen, nai ma cai d¢t mOt mang ha
tang
truyen thong tieu Mn theri gian vit chi phi cao.
Cic mang thong thubng sir dung the node chuyen dung de mang cic chirc
nang ca bin nhu chuyen tiep gai, djnh
tuyen, vi quart ly mang.
Trong mang
adhoc, cic chirc nang tor

' duce tbArc hien bang each Ong tic cac node co kha
nang. Cic node trong mang MANET sir dung lien ket multihop: cic node ben
trong vimg phn song cis node khic c6 the lien ket true tiep qua cic lien ket khong
day, trong khi nhUng node kit& a xa phiti dins vio uric node trung gian. Cie node
di &Ong c6 the di chuyen, rat gia nhop mpg, va cic tuyen can phai cjp nh#t lien
tic phi hqp yen topo mpg dOng. Vi du: node S c6 the lien ket veri node D bang
each sir dung dm:mg di non nit& S-A-B-D. Neu node A di chuyen ra ngoiti pham
vi dm node S, no se tim duang thay the den node D (S-C-E-B-D).
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Hinh 2.7: Lien kit gifia the node trong mgng MANET
Met lord cac giao thirc m6i de duqc phat trier cho viec tim kiem, cep ilk* the
tuyen va cung cep lien ket giita cac diem au cu6i (nhtmg cho den nay giao thirc
dtrqc de xuat van chua duqc chip nhen nhu la met chuen). Tuy nhien, cac giao
thirc djnh tuyen men dkra tren viec hqp the giera the node
a
bi ton thucmg beri the
cuec tin ding mei. That khong may khi the giao thirc djnh
tuyen
duce di
xuAt
cho
mang MANET kitting can nit& an yen de Wm met. Han nita, yeti the dec firth efia
chting nhu thieu cac diem trung tam, topo mang Ong, va cac gieri han
ten mi
cita
node 'Jet ra thaeh thirc cho yen de bito m0. Nhieu nghien eau a ducre thtrc hien de
chart va phfit hien the cuee tan Ong phi hoai the giao thirc dinh tuyen trong mang
MANET, bao gOm bito mot the giao thirc

djnh tuyen
va the he thting phat hien
xant nhep (IDS). Tuy nhien do met
s6 li
do ma the giii phfip duqc de
xuAt
top
trung vao met
s6
diem
yeu
bao met tir met gal phip
tong
quit la khong ding ke.
2.3.2. Cfic
diem yeu cea luting
MANET
Voi cac dee tinh cua mang MANET trinh bay a tren dit det ra thach thirc cho
cac giai phap bio met. MOt se cac bien phip bito met hien tai cho mang truyen
thong ter nen khong hieu qua khi trien khai trong mei truing MANET. Do d6 cac
nha nghien cuu a phfit trier cac gifii phfip mei hoec thay d6i the &Ai phap hien tai
cho phir hqp v6i mang MANET. Cie giao thirc dinh tuyen c6 the cluqc de
xuAt
de
chin cac host &Ong co lop bang each bit cac node c6 lep tong tic. Cic cc the
kh6a quitn 15
,
hien nay thuang dqa tren the diem trung tam nai cung cep cac djch
vtt nhu cc quan Chung nhert (CA) va may chit quan trong (KS) et!) the dtrqc thiet
lip. Mang MANET khong c6 the diem trung tam, the cc the kh6a quin 15

,
mei
duqc phat trier de dap img cac you
clu.
Khi the cong nghe phong ch6ng chi co
hieu qua gieti hen, cac
he
thong phat hien (IDS) duce dui vao de bo sung cho cac
ea the bio met }chic. Cfic diem yeu cis mang MANET:
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