nh gi hiu sut ca Ad Hoc Routing Protocols s dng m phng ns2
Abstract- Mt mng ad hoc l mt tp hp cc nt di ng khng dy t ng hnh
thnh mt mng tm thi khng s dng bt k c s h tng mng hin c hoc qun tr
tp trung. Mt s giao thc nh tuyn nh ng Source Routing (DSR), Ad Hoc
On-Demand Distance Vector Routing (AODV), Destination sp xp trnh t
Distance-Vector (DSDV) v thi Ordered Routing Algorithm (Tora) c thc
hin. Trong d n ny l mt n lc c thc hin so snh hiu sut ca hai ni bt
theo yu cu giao thc nh tuyn phn ng cho cc mng di ng ad hoc: DSR v
AODV, cng vi cc giao thc DSDV ch ng truyn thng. Mt m hnh m phng vi
MAC v cc m hnh lp vt l c s dng nghin cu s tng tc xen v tc ng hiu qu
ca h. Cc giao thc theo yu cu, AODV v DSR thc hin tt hn so vi bng iu
khin giao thc DSDV. Mc d DSR v AODV chia s hnh vi tng t theo yu cu,
s khc bit trong c ch giao thc c th dn n s khc bit v hiu sut ng k.
Nhng khc bit v hiu sut c phn tch bng cch s dng khc nhau ti mng, di
ng, v kch thc mng. Nhng m phng c thc hin da trn cc d n Monarch Rice
thc hin m rng ng k vi mng ns-2 gi lp chy m phng ad hoc.
Mc lc1. Gii Thiu1.1 mng Infrastructured1.2 mng
Infrastructureless 32. M t cc giao thc nh tuyn ad-hoc2.1 im n sp xp
trnh t Distance-Vector (DSDV)2.2 tm Ordered Routing Algorithm
(Tora)2.3 Nng ng Ngun Routing (DSR)2.4 Ad Hoc On-Demand Distance
Vector Routing (AODV)43. M phng m hnh3.1 Cc giao thng v Mobility
Models64. Hiu sut Metrics4.1 Packet giao phn4.2 Trung bnh
end-to-end chm tr ca cc gi d liu4.3 ti nh tuyn bnh thng ha65. Thc
hin5.1 Lp t ns-25.2 Hiu c vn c bn lin quan n ns-2 m phng5.3 m rng
khng dy ca CMU ns-25.4 To giao thng v di ng m hnhM 5.5 M phng76. Kt
qu v tho lun6.1 So snh hiu nng ca cc giao thc6.1.1 So snh gi giao
hng6.1.2 Trung bnh End-End giao Packet6.2 khc nhau Mobility v S
Sources thy s khc bit hiu sutgia DSR v AODV6.2.1 So snh gi giao
hng6.2.2 Trung bnh End-End giao Packet107. Quan st7.1 nh hng ca
Mobility7.2 Routing ti Effect148. Kt lun 159. Tng lai lm vic 15A.
Ti liu tham kho 15B. Ph lc1. Tcl Simulation M2. Java Parser M 161.
Gii Thiu
Mng khng dy l mt cng ngh mi ni, cho php ngi dng truy cp thng tin
v cc dch v in t, bt k v tr a l ca h. Cc mng khng dy c th c phn loi
thnh hai loi: -
1.1 mng Infrastructured.Mng Infrastructured bao gm mt mng li vi
cc cng c nh v khng dy. Mt lot in thoi di ng giao tip vi mt cy cu
trong mng (gi l trm gc) trong vng bn knh truyn thng. Cc n v in thoi
di ng c th di chuyn v a l trong khi n ang giao tip. Khi n i ra khi
phm vi ca mt trm c s, n kt ni vi trm gc mi v bt u giao tip thng qua
n. iu ny c gi l bn giao. Trong phng php ny, cc trm gc c c nh.
1,2 Infrastructureless (Ad hoc) mng.Trong cc mng ad hoc tt c cc
nt l in thoi di ng v c th c kt ni t ng mt cch tu tin. Tt c cc nt ca
cc mng ny hnh x nh cc b nh tuyn v tham gia khm ph v bo tr cc tuyn
ng n cc nt khc trong mng. Hoc mng qung co l rt hu ch trong trng hp
khn cp tm kim v cu h cc hot ng, cc cuc hp hoc hi ngh m trong ngi
mun nhanh chng chia s thng tin, v cc hot ng thu thp d liu a hnh khc
nghit.
Cc giao thc ad-hoc nh tuyn c th c chia thnh hai loi:1. Bng iu
khin giao thc nh tuyn.Trong bng iu khin cc giao thc nh tuyn, thng
nht v up-to-date thng tin nh tuyn cho tt c cc nt c duy tr ti mi
nt.
2. On-Demand giao thc nh tuyn.Trong cc giao thc nh tuyn
On-Demand, cc tuyn c to ra v khi cn thit. Khi mt ngun mun gi n mt
ch n, n vin dn c ch khm ph tuyn tm ng i n ch.
Trong nhng nm gn y, mt lot cc giao thc nh tuyn mi nhm mc ch tm
mi trng ny c pht trin. C bn multi-hop khng dy ad hoc cc giao thc nh
tuyn mng m bao gm mt lot cc la chn thit k:1. im n sp xp trnh t
Distance-Vector (DSDV)2. tm Ordered Routing Algorithm (Tora)3. Ngun
Dynamic Routing (DSR)4. Ad Hoc On-Demand Distance Vector Routing
(AODV).
Trong khi DSDV l mt bng iu khin giao thc nh tuyn, TORA, DSR,
AODV, thuc th loi giao thc nh tuyn theo yu cu.
2. M t v Routing Protocols Ad-hoc
im n sp xp trnh t Distance-Vector (DSDV)
Cc Destination-tip ni theo Distance-Vector (DSDV) Routing
Algorithm c da trn tng ca cc c in Bellman-Ford Routing Algorithm vi
nhng ci tin nht nh.Mi trm di ng duy tr mt bng nh tuyn m lit k tt c
cc im c sn, s lng hoa bia t n ch v s th t ca cc node ch c giao. Cc
s th t c s dng phn bit cc tuyn ng c t nhng ngi mi v do trnh s hnh
thnh ca cc vng. Cc i truyn k bng nh tuyn ca cc nc lng ging ca h
ngay lp tc. Mt trm cng truyn bng nh tuyn ca n nu mt s thay i ng k
xy ra trong bng t bn cp nht mi nht c gi. V vy, bn cp nht va mt thi
gian iu khin v hng s kin.Cc bn cp nht bng nh tuyn c th c gi bng hai
cch: - "y dump" hoc cp nht mt gia tng. Mt bi cha y s gi bng nh tuyn
y cho nhng ngi hng xm v c th tri rng nhiu gi tin trong khi trong mt
cp nht gia tng ch nhng mc t bng nh tuyn c gi m c mt thay i s liu t
cc bn cp nht mi nht v n phi ph hp trong mt gi. Nu c khng gian trong
cc gi cp nht gia tng th nhng mc c th c bao gm c s th t thay i. Khi
mng l tng i n nh, cp nht gia tng c gi trnh giao thng thm v y bi l
khng thng xuyn. Trong mt mng thay i nhanh chng, cc gi gia tng c th
pht trin ln bi nh vy y s c thng xuyn hn.Tm Ordered Routing
Algorithm (Tora)Tora l mt giao thc nh tuyn phn phi da trn mt "lin
kt ngc" thut ton. N c thit k pht hin ra cc tuyn ng theo yu cu, cung
cp nhiu tuyn n mt ch, thit lp cc tuyn ng nhanh chng v gim thiu chi
ph thng tin lin lc bng a ha phn ng thut ton thay i topo khi c th.
Route ti u (ngn nht con ng nh tuyn) c coi l c tm quan trng th yu, v
cc tuyn ng di thng c s dng trnh vic pht hin ra cc tuyn ng mi.
Cc hnh ng ca Tora c th c m t theo dng nc chy xung dc hng ti mt
node ch thng qua mt mng li cc ng rng m hnh trng thi nh tuyn ca mng
thc s. Cc ng by cc lin kt gia cc nt trong mng, cc mi ni ca ng i din
cho cc nt, v cc nc trong ng i din cho cc gi chy v pha ch. Mi nt c
mt chiu cao i vi cc im n m c tnh bng cc giao thc nh tuyn vi. Nu mt
ng gia cc nt A v B b nghn nh vy m nc khng cn c th lu thng qua n,
chiu cao ca A c thit lp mt chiu cao ln hn so vi bt k nc lng ging cn
li ca n, nh vy nc s chy ngc ra khi A ( v hng ti cc nt khc c nh tuyn
cc gi tin n ch thng qua A).
Khi mt nt pht hin ra rng mt tuyn ng n mt ch n l khng cn gi tr, n
iu chnh chiu cao ca mnh n l mt a phng ti a i vi cc nc lng ging vi v
truyn mt gi tin UPDATE. Nu nt khng c ngi hng xm ca chiu cao hu hn i
vi im n ny vi, sau nt thay v c gng khm ph mt con ng mi nh m t trn.
Khi mt nt pht hin mt phn vng mng, n to ra mt gi tin CLEAR m reset
bang tuyn v loi b cc tuyn ng khng hp l t mng.
Ngun nng ng nh tuyn (DSR)
Cc tnh nng phn bit ch yu ca DSR l vic s dng cc d liu nh tuyn. l,
ngi gi bit cc hop-by-hop ng hon chnh n ch. Nhng ng bay ny c lu tr
trong b nh cache tuyn ng. Cc gi d liu mang theo con ng m ngun trong
tiu gi. Khi mt nt trong mng ad hoc c gng gi mt gi d liu n mt ch n m
n cha bit ng, n s dng mt qu trnh khm ph tuyn t ng xc nh mt l trnh
nh vy. Route pht hin hot ng bng cch lm ngp mng vi yu cu ng (RREQ)
cc gi tin. Mi nt nhn c mt RREQ rebroadcasts n, tr khi n l im n hoc
n c mt tuyn ng n ch trong b nh cache tuyn ca mnh. Mt nt tr li cho
ch RREQ vi mt tuyn ng tr li (RREP) gi tin c nh tuyn tr li ngun gc.
RREQ v RREP gi cng l ngun chuyn. Cc RREQ xy dng ln con ng i qua trn
mng. Cc tuyn ng RREP chnh n tr li vi ngun bng cch i qua con ng ny
lc hu. Cc tuyn ng mang li bi cc gi tin RREP c lu tr ti ngun s dng
trong tng lai.
Nu bt c lin kt trn mt tuyn ng ngun b hng, nt ngun c thng bo s
dng mt li ng (RERR) gi tin. Cc ngun loi b bt k tuyn ng bng cch s
dng lin kt ny t b nh cache ca n. Mt qu trnh khm ph tuyn mi phi c
khi xng bi cc ngun nu tuyn ng ny vn cn cn thit. DSR lm cho vic s
dng rt tch cc ca cc d liu nh tuyn v tuyn ng b nh m. Khng c c ch c
bit pht hin vng lp nh tuyn l cn thit. Ngoi ra, bt k nt chuyn tip lu
tr cc tuyn ng ngun trong mt gi tin n s chuyn tip cho kh nng s dng
trong tng lai.
Hoc On-Demand Distance Vector Routing qung co (AODV)
AODV c phiu DSR ca c im ch n cng pht hin ra cc tuyn ng trn c s
khi cn thit thng qua mt qu trnh khm ph tuyn tng t theo yu cu. Tuy
nhin, AODV thng qua mt c ch rt khc nhau duy tr thng tin nh tuyn. N
s dng cc bng nh tuyn truyn thng, mt trong nhng mc ch trn. iu ny tri
ngc vi DSR, m c th duy tr nhiu mc tuyn ng b nh cache cho mi im n.
Nu khng c d liu nh tuyn, nh tuyn AODV da trn bng mc tuyn truyn mt
RREP tr v ngun v, sau , nh tuyn cc gi d liu n ch. AODV s dng s th t
duy tr ti mi im n xc nh ti ca thng tin nh tuyn v ngn chn vng lp nh
tuyn. Tt c cc gi tin nh tuyn thc hin cc s th t.
Mt tnh nng quan trng ca AODV l vic duy tr trng thi hn gi-c tr s
ti mi nt, lin quan n vic s dng ca c nhn cc entry bng nh tuyn. Mt
entry bng nh tuyn l ht hn nu khng c s dng gn y. Mt tp hp cc nt tin
nhim c duy tr cho mi entry bng nh tuyn, cho thy tp hp cc nt ln cn m
s dng nhp nh tuyn cc gi d liu. Cc nt c thng bo vi cc gi tin RERR
khi v lin kt next-hop. Mi nt trc, ln lt, chuyn tip RERR thit lp
ring ca ngi tin nhim, th xo c hiu qu tt c cc tuyn ng bng cch s dng
cc lin kt b hng. Ngc li vi DSR, cc gi tin RERR trong AODV nhm thng
bo cho tt c cc ngun s dng mt lin kt khi c s c xy ra. Route li tuyn
truyn trong AODV c th c hnh dung khi nim nh l mt cy c gc l nt ti cc
im ca s tht bi v tt c cc ngun s dng lin kt tht bi nh nhng chic
l.
3. m hnh m phng
Mt m hnh m phng chi tit da trn ns-2 c s dng trong vic nh gi.
Trong mt bi bo gn y ca nhm nghin cu ti i hc Carnegie Monarch-Mellon
pht trin h tr cho m phng cc mng khng dy multihop hon chnh vi vt l,
lin kt d liu, trung bnh v kim sot truy cp (MAC) m hnh lp trn ns-2.
Chc nng iu phi phn tn (DCF) ca IEEE 802.11 cho mng LAN khng dy c s
dng nh mt giao thc lp MAC. Mt cm nhn sng mang unslotted a truy nhp
(CSMA) k thut trnh xung t (CSMA / CA) c s dng truyn ti cc gi d liu.
Cc m hnh pht thanh s dng cc c tnh tng t nh mt giao din v tuyn thng
mi, WaveLAN Lucent. WaveLAN c m phng nh mt i pht thanh chia s phng
tin vi tc bit danh ngha ca 2 Mb / s v mt lot i danh ngha l 250
m.
Cc giao thc duy tr mt b m gi 64 gi. N cha tt c cc gi d liu ch i
cho mt l trnh, chng hn nh cc gi m khm ph tuyn bt u, nhng khng c tr
li n cha. ngn chn m ca cc gi d liu v hn nh, cc gi tin c gim xung nu
h ch i trong b m gi cho hn 30 s. Tt c cc gi (c d liu v nh tuyn) gi
bi lp nh tuyn c xp hng ti cc hng i giao din cho n khi lp MAC c th
truyn chng. Cc hng i giao din c kch thc ti a 50 gi v c duy tr nh mt
hng i u tin vi hai tin-quan h tng phc v trong FIFO trt t. Cc gi tin
nh tuyn c u tin cao hn cc gi d liu.
3.1 Cc giao thng v Mobility Models
Tc bit lin tc (CBR) ngun lu lng c s dng. Cc cp ngun-ch c lan
truyn mt cch ngu nhin trn mng. Ch c cc gi d liu 512-byte c s dng. S
cp ngun-ch v tc gi gi trong mi cp c thay i thay i ti c cung cp
trong mng.
M hnh di ng s dng cc m hnh waypoint ngu nhin trong mt lnh vc hnh
ch nht. Cc cu hnh a c s dng l: 500 mx 500 m lnh vc vi 50 nt. y, mi
gi tin bt u cuc hnh trnh ca mnh t mt v tr ngu nhin vo mt im n ngu
nhin vi mt tc c chn ngu nhin (phn b ng u gia 0-20 m / s). Mt khi cc
im n c t ti, mt im n ngu nhin l mc tiu sau khi tm dng. Thi gian tm
dng, m nh hng n tc tng i ca cc in thoi di ng, c thay i. M phng c
chy cho 100 giy m phng. Tnh di ng v lu lng truy cp kch bn ging ht
nhau c s dng trn cc giao thc thu thp kt qu cng bng.
4. Hiu sut Metrics
Ba s liu hiu sut quan trng c nh gi:
4.1 Packet giao phn - T l cc gi d liu gi n nhng a im n nhng ngi
to ra bi cc ngun CBR.4.2 Trung bnh end-to-end chm tr ca cc gi d liu
- bao gm tt c s chm tr c th gy rabi m trong l trnh pht hin tr, xp
hng ti cc hng i giao din,s chm tr truyn li ti MAC, v tuyn truyn,
chuyn giao ln.4.3 ti nh tuyn bnh thng ha - S lng cc gi tin nh tuyn
truyn mi gi d liu giao ti ni n. Mi truyn hop-khn ngoan ca mt gi tin
nh tuyn c tnh l mt truyn.
Hai s liu u tin l quan trng nht cho giao thng n lc tt nht. Cc s
liu ti nh tuyn nh gi hiu qu ca cc giao thc nh tuyn. Lu , tuy nhin,
nhng s liu khng phi l hon ton c lp. V d, di phn a gi c ngha rng s
liu chm tr c nh gi c t mu hn. Trong s khn ngoan thng thng, cn con
ng di, cao hn xc sut ca mt git gi. Nh vy, vi mt phn phn phi thp, cc
mu thng c thin v trong li ca di ng i nh hn v do c t chm tr.
5. Thc hin
Ci t ns-2
Ns-2 mng m phng c ci t t trang
webhttp://www.isi.edu/nsnam/ns/
Lp t ns-2 c th l mt cht di dng v mt qu trnh tn nhiu thi gian. N
lin quan n vic ti v v ci t mt gi 250 MB. Tuy nhin, nhn c gi lp lm
vic l bc u tin tham gia vo vic thc hin cc m phng.
5.2 Hiu c vn c bn lin quan n ns-2 m phng
Mt hng dn rt tt hiu c bn m phng ns-2 c sn ti trang
web:http://www.isi.edu/nsnam/ns/tutorial/index.html
5.3 m rng khng dy ca CMU ns-2
M rng khng dy ca CMU ns-2 (kt hp trong vic pht hin ns-2.1b9a)
cung cp cho vic thc hin cc giao thc nh tuyn DSR, AODV, DSDV,
Tora.Nam l cng c trc quan c bn c s dng cho ns-2 m phng. Tuy nhin, n
khng h tr cc m phng ad-hoc. Ad-hockey l mt chng trnh Perl / Tk h tr
trc quan ca m phng ad-hoc. Tht khng may, ti khng th c c cng c
visualizer Ad-hockey lm vic v vn tng thch ca n vi cc phin bn mi ca
Perl / Tk module.
5.4 To giao thng v di ng m hnh
M hnh giao thng
Kt ni giao thng ngu nhin ca TCP v CBR c th c thit lp gia cc nt
di ng bng cch s dng mt my pht in script giao thng-kch bn. Kch bn
pht in giao thng ny c pht hnh theo ~ ns / indep-utils /
CMU-scen-gen v c gi l cbrgen.tcl. N c th c s dng to CBR v TCP nng
kim cc kt ni gia mobilenodes khng dy. V vy, cc dng lnh nh sau:
ns cbrgen.tcl [-type cbr | tcp] [-nn nt] [ht -seed] [kt ni -mc]
[- li sut]
i vi cc m phng c thc hin, m hnh giao thng c to ra cho 50 nt giao
thng vi cc ngun cbr, vi cc kt ni ti a 10,20,30,40 vi tc 8kbps.
M hnh MobilityCc my pht in node-phong tro c pht hnh theo ~-utils
indep / CMU-scen-gen th mc ns / / setdest v gm setdest {.cc, h} v
Makefile. Cc cu lnh s nh./setdest [-n num_of_nodes] [-p pausetime]
[-s maxspeed] [-t simtime] \ [-x maxx] [maxy -y]> [outdir /
chuyn ng-file]
M hnh di ng c to ra cho cc m phng s dng 50 nt, vi thi gian tm
dng ca 0,10,20,40,100 giy, tc ti a 20m / s, topology ranh gii c kch
thc 500x500 v thi gian m phng ca 100secs.
Lu : M phng c th c thc hin vi nhiu tnh hung phc tp s dng cc mc
lu lng truy cp cao hn. Tuy nhin, cc m phng mt nhiu thi gian hon
thnh v cc du vt tp tin c to ra bi mi ln chy kt thc ln n hn 50 Mb
khng gian s dng.
M 5.5 M phng
Vit m Tcl thit lp cc thnh phn khng dy m phng: cc thnh phn mng
loi, thng s nh cc loi ng-ten, cc m hnh pht thanh-truyn, cc loi qung
co-hoc giao thc nh tuyn, m hnh giao thng v cc m hnh chuyn ng nt c s
dng bi cc nt di ng vv M ti liu c sn trong Ph lc.
5.5 Phn tch cc du vt tp tin m phng
Sau mi m phng, theo di cc tp tin ghi m cc phong tro giao thng v
nt c to ra. Nhng tp tin cn phi c phn tch trch xut cc thng tin cn
thit o cc s liu hiu sut. Cc nh dng du vt mi c s dng phn tch.
Cc nh dng du vt mi trng ging nh:
s -t 0,267662078 -Hs 0 -HD -1 -Ni 0 -Nx 5.00 -Ny 2.00 -Nz 0.00
-ne -1,000000 -Nl RTR -Nw --- -Ma 0 -Md 0 0 -ms-MT 0 -ii 20 -l
0,255 -1,255 -ID -N
y, chng ta thy rng mt gi tin c gi i (s) vo thi gian (t)
0,267662078 giy, t nt ngun (Hs) 0 n node ch (HD) 1. Cc nt ngun id
(Ni) l 0, l x-ng phi (NX) l 5,00, n y-co-ordinate (Ny) l 2.00, l
z-co-ordinate (NZ) l 0,00, l mc nng lng (Ne) l 1,000000, mc vt (Nl)
l RTR v nt s kin (Nw) l trng. Cc thng tin cp MAC c cho bi thi gian
(Ma) 0, a ch Ethernet ch (Md) 0, a ch ngun Ethernet (Ms) l 0 v loi
Ethernet (Mt) l 0.Cc thng tin mc gi d liu IP nh gi id (Ii), s cng
address.source ngun c cho bi (Is) trong khi s lng cng
address.destination ch l (Id).
5.5.1 nh gi cc giao Packet phn (pdf):
Tnh s "cc gi tin gi" c dng du vt:
/ S ^ * -. Nl AGT * - Liu (\ d {1,3}) \ \ d {1,3} -ID (\ d
{1,3}) \ \ d {1,3}... * cbr -N * -. Ii (\ d {1,6}) /AGT => Agent
Cp vtTnh s "gi tin nhn c" ca cc hnh thc du vt:
/ R ^ -t (\ d {1,3} \ \ d {9}.) * -. Nl AGT * -.. Liu (\ d
{1,3}) \ \ d {1,3} -ID (\ d {1,3}) \ \ d {1,3} * -... N cbr * - Ii
(\ d {1,6}) /
a gi phn (pdf%) = (gi tin nhn / gi cc gi tin) * 100
5.5.2 nh gi trung bnh End-End thi gian giao hng gi:
i vi mi gi tin vi id (Ii) cp du vt (AGT) v loi (CBR), tnh ton
send (s) thi gian (t) v nhn (r) thi gian (t) v trung bnh n.
5.5.3 nh gi cc ph ti nh tuyn bnh thng ha:
Tnh ton cc gi tin nh tuyn gi:/^[s|f].*-Nl RTR * - N. (?: AODV |
DSR | tin nhn) il (\ d {1,4}) /
f => v pha trcRTR => Routing vt CpBnh thng ha nh tuyn ti =
(gi nh tuyn gi) / nhn.
6. Kt qu v tho lun
Hnh 1
Hnh 2
6.1 So snh hiu nng ca giao thc:
u tin, mt n lc c thc hin so snh tt c cc giao thc 4 trong mi trng
m phng tng t. Tuy nhin, m phng c th khng c thc hin thnh cng cho cc
giao thc nh tuyn TORA, nh ns-2 nhiu ln cho mt li trong khi xe but
chy cc m phng Tora. i vi tt c cc m phng, cc m hnh chuyn ng tng t c
s dng, s lng cc ngun lu lng truy cp c c nh mc 20, tc ti a ca cc nt
c thit lp n 20m / s v thi gian tm dng c thay i nh 0s, 10s, 20s, 40s
v 100s .
Hnh 1 v 2 lm ni bt cc hiu sut tng i ca ba giao thc nh tuyn. Tt c
cc giao thc cung cp mt t l ln hn ca cc gi d liu c ngun gc khi c rt
t nt di ng (v d, ti thi im tm dng ln), hi t giao hng 100% khi khng
c chuyn ng node.
6.1.1 Packet giao hng So snh:
Cc giao thc theo yu cu, DSR v AODV thc hin c bit tt, cung cp hn
85% ca cc gi d liu bt k tc di chuyn.
6.1.2 Trung bnh End-End Packet giao hng:
The end-to-end tr trung bnh ca gi giao hng cao hn DSDV so vi c
DSR v AODV.
Tm li, c hai theo yu cu giao thc nh tuyn, AODV v DSR vt tri so
vi cc giao thc nh tuyn Bng iu khin; DSDV v l do c tho lun sau.
Tip theo, v c hai AODV v DSR lm tt hn, mt n lc c thc hin nh gi s
khc bit v hiu nng gia hai bng cch thay i cc m hnh ng v S lng ngun
lu lng truy cp.
6.2 khc nhau Mobility v S Sources thy s khc bit v hiu nng gia
DSR v AODVBy gi, mt ln na m phng c thc hin vi s lng cc ngun lu lng
truy cp l 10, 20, 30 v 40. Thi gian tm dng c thay i l 0 (tnh di ng
cao), 10, 20, 40.100 (khng c di ng) v cc gi tin c gi t l 4 gi tin /
giy.
6.2.1 Packet giao hng So snh:
Cc phn a gi cho DSR v AODV l tng t vi 10 ngun (Hnh. 3a). Tuy
nhin, vi 20, 30 v 40 ngun, AODV nhanh hn so vi DSR khong 15 phn trm
(Hnh 3c. V 3d) ln tm dng thp hn (tnh di ng cao hn).
6.2.2 Chun ha Routing ti so snh:
Trong mi trng hp, DSR chng minh ti nh tuyn thp hn ng k so vi
AODV (Fig. 4), vi cc yu t gia tng vi mt s lng ngy cng tng ca
ngun.Hnh 3 (a)Hnh 4 (a)
Hnh 3 (b)Hnh 4 (b)
Hnh 3 (c)Hnh 4 (c)
Hnh 3 (d)Hnh 4 (d)
Tm li, khi s lng cc ngun thp, hiu sut ca DSR v AODV l tng t bt k
tnh di ng. Vi s lng ln cc ngun, AODV bt u t vt DSR cho cc kch
bn-tnh di ng cao. Theo d liu t cc ngun khc nhau chng minh, AODV bt
u t vt DSR ti thp hn vi mt s lng ln cc nt. DSR lun chng t mt ti nh
tuyn thp hn AODV. S ng gp ln cho nh tuyn AODV ca qu u l t yu cu
tuyn ng, trong khi tuyn ng tr li to thnh mt phn ln ca nh tuyn trn
ca DSR. Hn na, AODV c yu cu tuyn ng hn DSR, v ngc li mi l ng i vi
cc tuyn ng tr li.
7. Quan st
Cc kt qu m phng a ra mt s s khc bit c trng quan trng gia cc giao
thc nh tuyn.
S hin din ca tnh di ng cao ng tht bi lin kt thng xuyn v mi giao
thc nh tuyn phn ng khc nhau trong thi gian mt lin kt. Cc c ch lm
vic c bn khc nhau ca cc giao thc ny dn n s khc bit trong vic thc
hin
DSDV khng hi t di ln tm dng thp hn. Vi tc cao hn ca tnh di ng
(thptm dng ln), DSDV khng km, tt xung mt t l gi de-mu sn 70%. Gn nh
tt c cc gi gim c mt v mt mc bng nh tuyn c hng dn h c chuyn tip qua
mt lin kt b hng. Nh m t phn trc, DSDV duy tr ch c mt tuyn ng mi im
n v do , mi gi tin rng cc lp MAC l khng th cung cp c gim v khng c
tuyn ng thay th.
i vi DSR v AODV, t l giao gi tin l c lp vi ti lu lng cho bn, vi
c hai giao thc cung cp t 85% n 100% ca cc gi d liu trong mi trng
hp.
K t DSDV s dng phng php bng iu khin duy tr thng tin nh tuyn, n
khng phi l thch ng vi nhng thay i tuyn ng xy ra trong tnh di ng
cao. Ngc li, cc phng php tip cn li bing c s dng bi cc giao thc theo
yu cu, AODV v DSR xy dng cc thng tin nh tuyn v khi chng c to ra lm
cho h thch nghi hn v dn n hiu sut tt hn (gi cao giao phn nh v kt
thc end-to-trung bnh thp s chm tr gi tin).
Tip theo cc kt qu m phng ca cc con s 3 v 4, m so snh cc mn trnh
din ca AODV v DSR dn chng ta n kt lun sau y.
7.1 nh hng ca Mobility:
Trong s hin din ca tnh di ng cao, tht bi lin kt c th xy ra rt
thng xuyn. Tht bi lin kt kch hot nhng khm ph con ng mi trong AODV v
n c nhiu nht mt tuyn ng mi ch trong bng nh tuyn ca n. Nh vy, tn s
ca nhng khm ph tuyn ng trong AODV l t l thun vi s lng v ng. Phn ng
ca DSR lin kt tht bi trong so snh l nh v gy khm ph tuyn t thng xuyn
hn. L do l s phong ph ca cc tuyn ng c lu tr ti mi nt. V vy, vic pht
hin ra tuyn ng b tr hon trong DSR cho n khi tt c cc tuyn cache tht
bi. Nhng vi tnh di ng cao, c hi ca cc cache l c l kh cao trong DSR.
Cui cng khi mt khm ph tuyn c bt u, s lng ln tr li nhn c trong phn
ng c lin quan vi overhead MAC cao v gy ra tng can thip lu lng d
liu. Do , cc staleness b nh cache v trn MAC cao cng dn n suy gim ng
k trong hot ng cho DSR trong cc kch bn di ng cao.
Trong kch bn di ng thp hn, DSR thng hot ng tt hn AODV, v c hi tm
thy cc tuyn ng trong mt trong cc cache cao hn rt nhiu. Tuy nhin, do
mi trng rng buc m phng (m phng thi gian t hn v cc m hnh tnh di ng
thp hn), hiu sut tt hn ca DSR hn AODV c th khng c quan st thy.
7.2 Routing ti Effect:
DSR hu nh lun lun c mt ti nh tuyn thp hn AODV. iu ny c th c quy
cho cc chin lc b nh m c s dng bi DSR. Nh b nh m tch cc, DSR c nhiu
kh nng tm mt con ng trong b nh cache, v do phi vin n khm ph tuyn t
thng xuyn hn AODV.
8. Kt lun
D n ny so snh hiu sut ca DSDV, AODV v giao thc nh tuyn DSR cc
mng ad hoc s dng ns-2 m phng. Tht khng may, TORA m phng c th khng c
thc hin thnh cng.
DSDV s dng cc chin lc nh tuyn bng nh hng ch ng trong khi c hai
AODV v DSR s dng cc phn ng theo yu cu chin lc nh tuyn. C hai AODV v
DSR thc hin tt hn trong m phng ng cao hn DSDV. Kt qu tnh di ng cao
trong nhng tht bi lin kt thng xuyn vnhng ph lin quan n vic cp nht
tt c cc nt vi cc thng tin nh tuyn mi nh trong DSDV l nhiu hn th
AODV v DSR tham gia, ni cc tuyn c to ra v khi cn thit.
DSR v AODV u s dng theo yu cu tuyn ng khm ph, nhng vi c ch nh
tuyn khc nhau. c bit, DSR s dng d liu nh tuyn v lu tr ng, v khng ph
thuc vo bt k hot ng nh k hoc hn gi da trn. DSR khai thc b nh m tch
cc v duy tr nhiu tuyn ng mi im n. AODV, mt khc, s dng bng nh tuyn,
mt tuyn ng mi im n, v s th t ch, mt c ch ngn chn vng lp v xc nh ti
ca cc tuyn ng. Cc quan st chung chung t cc m phng l i vi cc s liu
nh hng ng dng nh phn a gi v chm trAODV, DSR nhanh hn so vi trong
nhiu tnh hung "cng thng" (ngha l s lng nh hn ca cc nt v ti thp hn v
/ hoc di ng), vi hiu sut tng khong cch vi s cng thng ngy cng tng(V
d, nhiu ti trng, tnh di ng cao hn). DSR, tuy nhin, lun to ra ti nh
tuyn t hn AODV. Cc mn trnh din ngho nn ca DSR ch yu c cho l do s
dng tch cc ca b nh m, v thiu ca bt k c ch ht hn tuyn ng c hoc xc nh
s ti mt ca cc tuyn ng khi nhiu la chn c sn. B nh m tch cc, tuy
nhin, c v nh gip DSR ti thp v cng gi ti nh tuyn ca n xung.
9. Tng lai lm vic
Trong tng lai, m phng phc tp rng ln c th c thc hin bng cch s dng
m s d n ny, t c mt su hn phn tch hiu sut ca qung co hoc cc giao thc
nh tuyn. TORA hiu giao thc c th c nghin cu qu.
A. Ti liu tham kho
[1]. J.Broch, D.A. Maltz, D.B.Johnson, Y-C. Hu v J.Jetcheva. Mt
so snh hiu suta-hop khng dy ad hoc cc giao thc nh tuyn mng.[2].
Samir R.Das, Charles E. Perkins, Elizabeth M. Royer. So snh hiu nng
caHai On-demand Routing Protocols cho Ad Hoc Networks.
B. Ph lc
1. M phng M
==================================================
==================# Xc nh cc ty chn#
=================================================
=====================set opt (chan) Channel / WirelessChannelset
opt (chng ) Tuyn truyn / TwoRayGroundset opt (netif) Phy /
WirelessPhyset opt (mac) Mac / 802_11set opt (ifq) Queue / DropTail
/ PriQueuet opt (ll) LLt opt (ant) Antenna / OmniAntennaset opt (x)
500; # X kch thc ca a hnhset opt (y) 500; # Y kch thc ca a hnhset
opt (ifqlen) 50; # max gi trong ifqt opt (ht) 0.0set opt (tr)
temp3.tr; tp tin # traceset opt (adhocRouting) DSDVset opt (nn) 50;
# bao nhiu nt c m phngset opt (cp) "kch bn / CBR-50-5-4"set opt
(sc) "kch bn / temp1"t opt (stop) 100,0; # m phng thi gian
==================================================
====================# Chng trnh chnh#
=================================================
=====================# Khi to bin ton cu# To ra V d m phngthit ns_
[Simulator mi]
# Thit lp knh khng dy, radio-m hnh v a hnh i tngthit wtopo [a
hnh mi]
# To ra du vt i tng cho ns v namtp tracefd [m $ opt (tr) w]$ Ns_
di-tt c $ tracefd# S dng nh dng tp tin du vt miNs_ $ s
dng-newtrace
# Xc nh topo$ Wtopo load_flatgrid $ opt (x) $ opt (y)
# To Thin Chathit god_ [to ra thn $ opt (nn)]
# Xc nh cch nt nn c tothit lp nt #global$ Ns_ nt-config
-adhocRouting $ opt (adhocRouting) \-llType $ opt (ll) \-macType $
opt (mac) \-ifqType $ opt (ifq) \-ifqLen $ opt (ifqlen) \-antType $
opt (ant) \-propType $ opt (chng ) \-phyType $ opt (netif)
\-channelType $ opt (chan) \-topoInstance $ wtopo \-agentTrace ON
\-routerTrace ON \-macTrace OFF
# To s quy nh ca cc nt [$ opt (nn)] v "nh km" chng# Vi knh.cho
{set i 0} {$ i
