De phat hien va chOng lgi tan ding wormhole, co hai kieu kiem soat chat the goi tin duce gich thieu nhu met kg, thujt hieu qua, cu the la thin gian va dja
ly. CS kiem soat thin gian, tit ca cac node trong MANET tinh toan thai gian hat han goi Te va bao gom Te trong cac goi tin ca.% no de cac gal khong the di xa hcm met khofing each a; the L. Khi met goi china thong tin nay den met node, node !thin so shah theri gian hien tai voi gia tri cita Te trong goi. Voi thong tin d6, node dich sau da th the quyet djnh, cho de met tin RREQ duqc gin qua duimg ham qua met lien ket Mc de cao de phuc vu mqc dich xau. Ngoii ra, Te duqc xitc thuc bin cite dau cuOi tham gia vi the no co the Ichong bi lim gia Uri cac node dec hai nhu MI va M2. Tuy nhien, kiem soat thiri gian can tat ca cac
node trong MANET de dOng be thin gian met cach chit che. khac, trong truimg hqp kiem soat dja ly tit ca cac node phai hitt hai logi thong tin lit vi tri ttrung img cua no trong MANET vi thin gian truyen. Dieu nay cho phop node nh#n danh gilt the lien ket van hang x6m bang cach tinh toan khoang each gifra no va ngulm cua goi tin.
Dora vim thong tin vi tri, cac giai phitp tiep duqc phat Wien de chaong lgi cac cuec tin cling wormhole. Vi du: trong nghien ciru cfia minh Dhillon vi vac dOng nghiep cung cap str bao ve chOng Igi tin citing wormhole, die biet la trong mpg MANET bang each sir dung giao thirc OLSR djnh tuyen. Tuy !Alien dieu nay you au mot su tich hqp dui ha ding kh6a cling khai veri theri gian deng be gift tit ca cac node. lit ca cac node trong khi phat met tin HELLO, chen vi tri hien tai cua no va cung in diu thin gian hien tgi a g6i HELLO. Met node tilfitn g6i HELLO tir node ling gieng cua no co the sau d6 sir dung thOng tin gin vito goi de tinh than khoing each gifts no va hang x6m. Trong throng
Phan Trung Nghia A08348 hqp khoing each firth toan virqt qua pham vi truyen din tai da, tin HELLO bi coi la Tact kha nghi (co the dtrqc chuyen qua dtrerng him thong qua tin ding wormhole).
Phan tich thong ke cling duce sir dung de phat hien cac cups tit' t ding wormhole. Vi du: Qian va ding nghiep di gieri thieu met phan tich thing ke tren dinh tuyen da dutmg. Cach nay tinh tat ca tan so tuang del dm tat ca cac lien ket o tat ca cac tuyen duce hinh thimh trong met kham pha tuytn don. Tin s6 cao nhit duce ?CAC (filth la lien ket wormhole. M#c du each nay di tang phi thip khi ap dung cho dinh tuyen da diremg, no lam viec khong tat vii cac giao thee dinh tuyen khring phai la da &tong nhu AODV.
Met giai phap kha thi ngin ch#n cac cuec tin cong wormhole la tich hop he thing phat hien veilhotic cac hg thing ngAn ch#n trong MANET. Cite hien phap khac cling duqc xem xet, ngoli cac he thong phat hien xam nhop dies tren phin mem, thiet ke phan ding doe biet va cac ky thuftt xir 15, tin hieu. Nhfmg gia thiet ding sau cac giai phap de nghi la neu cac bit de lieu &roc giri qua mot so module doe filet chi duqc biet den beri cac node king gieng, chimg co the khong bi anh huemg ben die tan cong wormhole 6 gan.
3.2.2. Tin cong his den (Blackhole)
Trong truing hqp tan cong h6 den, node dee hui "M" tuyen b6 co met tuyen tei Int tir node nguOn, "V", den dich "D" va truyen th8ng tin dinh tuyen gia nay an cac node khac trong MANET. Ket qua la nheng ngueri dung khac bi lira chuyen tiep cac g6i de lieu ctia hQ qua node dee NIL Vi du: neu mang muc tieu MANET sir dung AODV la giao thirc dinh tuyen, "M" c6 the tuo ra met tin RREP sai china met so the to dich Bong ton tui, no bang ho#c cao hunt so yeti tin RREQ tir node nun nhan (node nguOn "V"). Dieu nay co nglea la node dee hai "M" tuyen be no set him met tuyen men dAy de den dich. Dieu nay thee day "V" lira chop tuyen d#c the nay (V-A-B-M) de girl cac goi de lieu qua ke tin cong.
Hinh 3.3: Kjch ban met cuec ten cong he den
Do de "M" ce the ttr 9 lam tre/drop cac g6i de lieu hoc thay 461 not dung cita cac g6i. Tuy nhien, "M" c6 the g#p nil ro tir cac node ling gieng coa no, vi dv: "B" va/ho#c "F" c6 the giam sat va tim ra cac cuec tan cong. De trtinh bi phat hien, "M" co the ties Minh cac phien ben phirc top has cea tan cling he den trong d6 cac &Si tin bi chk va drop tat ca gel di! lieu, cac g6i bi ch(in duqc chuyen tiep met each chon loc. That v#y, khi "M" chi sirs dei cac g6i den tir "V" ma khong tae deng den cac g6i tir "B" hoc "F", no gitim nguy co bi phat hien bed cac node ling giong.