Tom Tat Luan Van.pdf (Nguyen Van Tien)

7/29/2019 Tom Tat Luan Van.pdf (Nguyen Van Tien)

1/12

1

Chng 1 GII THIU CHUNG1.1 Gii thiu v b giao thc1.1.1Gii thiu chung

B giao thc TCP/IP, gi tt l TCP/IP, l mt b cc giao thc truyn thng cit chng giao thc m Internet v hu ht cc mng my tnh thng mi ang chy trn. B giao thc ny c t tn theo hai giao thc chnh ca n l TCP (Giao thc iukhin Giao vn) v IP (Giao thc Lin mng). Chng cng l hai giao thc u tin cnh ngha.

1.1.2Cu trc phn lp ca b giao thc TCP/IPB giao thc TCP/IP c chia thnh 4 lp, hnh 1.1 trnh by cu trc phn lp

ca b giao thc TCP/IP so snh vi m hnh 7 lp OSI, mi lp c chc nng v nhim vkhc nhau.

Hnh 1.1: M hnh phn lp TCP/IP1.1.3Cc c th ca mng IP

Mng IP hot ng da trn nguyn l chuyn mch gi. D liu c truyn tidi dng cc gi IP lp mng (network layer). Mi gi l mt chui bit bao gm cc bitca d liu cn chuyn v cc bit do giao thc mng gn thm. 24 byte u tin (tc l 192bit u tin) ca gi IP mang thng tin ca cc giao thc, v d nh a ch IP ca my giv my nhn, chng loi giao thc lp truyn ti ang d ng... Phn ny thng c nhcn di tn gi phn mo u, cu trc phn mo u c trnh by trong hnh 1.2. Cnnhn mnh rng mi x l lin quan n gi IP, nh xc nh ng truyn, phn loi gi,u da hon ton vo nhng thng tin nm trong phn mo u.


2/12

2

Hnh 1.2: Cu trc phn mo u gi IP

1.2 Phn lp lu lng1.2.1Phn lp lu lng mc lp mng

Vic phn lp lu lng c thc hin ti c lp 2 (lp lin kt d liu) v lp 3(lp mng) trong m hnh OSI.

sp xp cc lung d liu IP thnh cc lp khc nhau nhm phc v cho ccchnh sch QoS khc nhau, chng ta s dng 3 bit u tin trong trng loi dch v(Service Type - ToS) trong phn mo u ca gi d liu IP. 3 bit ny c gi l trng IP

Precedence v c gi tr mc nh l 0. Trng IP Precedence bng 0 c ngha l gi tin nys c truyn theo kiu khng c am kt QoS (Best Effort). 7 bit c n li ca trng IPPrecedence dng phn chia lu lng IP thnh 7 lp dch v c th t u tin tng dn,cu trc trng IP Precedence c trnh by trong hnh 1.3.

Hnh 1.3: Phn lp lu lng theo IP Precedence

1.2.2Phn lp lu lng mc lp lin kt d liuTrong phn mo u ca khung d liu lp li n kt d liu khng c trng no

phc v cho vic phn lp lu lng. Tuy nhin ta c th phn lu lng da vo vic chnthm cc th nh danh VLAN gi l tag theo giao thc 802.1Q/p. Mitag gm 4 byte trong trng CoS gm 3 bit (cu trc chi tit ca tag c trnh by trong hnh 1.4) c dng phn lp lu lng. Nh vy ti mc lin kt d liu chng ta cng c th phn chia lulng thnh 8 lp vi cc mc u tin tng dn tng t nh khi s dng IP Precedence tilp mng ca gi tin IP.


3/12

22

trc, t l hu gi tin thp ngay c i vi cc lp cao hn v c kim sot tr vbin thin tr gi.

Hnh 4.6: T l mt gi

Kt qu ny

cho thy gii thut

thch nghi hot

ng tt vi vic

thay i cc iu

kin lu lng m

vn c th t

c thng lng

cao hn.

3

Hnh 1.4: Cu trc tag trong khung d liu 802.1Q/p

1.2.3Qun l nghn lu lngCc k thut qun l nghn lu lng cho php chng ta qun l nghn bng cch

xc nh th t gi gi tin ti cng giao tip u ra da trn u tin ca gi tin. Cng vicqun l nghn bao gm vic thit lp cc hng i, gn cc lp lu lng vo cc hng i v phn phi cc gi tin trong hng i ti cng giao tip u ra.

K thut x l nghn c s dng ph bin l RED. RED s hu cc gi tin mtcch ngu nhin phng trnh nghn xy ra. Gii thut RED s tnh kch thc hng itrung bnh (Q) s dng hm trung bnh di chuyn trng s m (EWMA). Sau so snh Qvi cc ngng hng i nh ngha trc l Tl v Th. Nu Q ln hn Tl v nh hn Th, nnh du gi tin trong hng i

1.3 Cc gii php QoS1.3.1Cu trc tch hp dch v IntServ

Mt mng IntServ in hnh cha cc b nh tuyn bin v cc b nh tuyn li(xem hnh v 1.5). Trc khi bt u truyn d liu ca mt lung IP vi m, u gi thngbo mt s s liu lin quan n lu lng s c chuyn (nh tc gi lu lng trungbnh ca u gi, ln cho php ca nhng cm bng pht lu lng) cho b nh tuynbin.

Hnh 1.5: Cu trc QoS tch hp dch v


4/12

4

Giao thc bo hiu RSVP s a ra quyt nh lung IP t nt H1 n nt H2 cth c mng IntServ phc v hay khng. Trc ht, RSVP xc nh v xy dng ngtruyn cho lung IP bng tin PATH. ng truyn ny i qua cc b nh tuyn R1, R2, R3.Tip dung lng s c chim gi cho ng truyn theo chiu t nt nhn ngc trli nt gi. S chim gi c thc hin bng tin RESV ca giao thc RSVP.

1.3.2Cu trc DiffServNguyn l hot ng ca cu trc DiffServ bao gm nhng im c bn sau. Khi

bt u i vo mng DiffServ m trc tip l ti b nh tuyn bin, gi IP s c phnloi. B nh tuyn bin thc hin vic phn loi bng cch kim tra m DSCP (hoc IPPrecedence) cha chng loi dch v nm trong phn u gi cng vi mt s d liu khclin quan n lung vi m ca gi IP (nh a ch u gi, a ch u nhn).

C hai phng php chnh c th tun theo khi trin khai thut ton iu khin lulng vo trn nn mng DiffServ. Phng php th nht l iu chnh d ng cu trc Brokerdung lng. Phng php th hai l iu chnh da vo cc kt qu o c, gim st trngthi ca mng. phng php th nht, mt thit b c bit c gi l Broker dung lngc lp t (xem hnh 1.6).

Hnh 1.6: Cu trc QoS DiffServ

21

Hnh 4.5: bin thin tr ca cc lp lu lng4.5.3T l mt gi

Theo nh hnh 4.5 ta thy cc gii thut iu khin lu lng vo thch nghi hub gi tin t hn (thm ch l bng 0) so vi gii thut CAR. Nh ta thy trong cc phn


5/12

20

4.5.2 bin thin trQua hnh 4.4 chng ta thy bin thin tr ca cc lp thp hn l cao hn, bin

thin tr ca lu lng video class 3 l thp nht.

5

Chng 2 QUN L BNG THNG TNH2.1 Gii thiu

iu khin l u lng vo s iu tit gi d liu n giao din mng u vo.Phn phi lu lng ra nh ngha quy tc dch v hng i cho cc giao di n mng u rabao gm th t cc gi tin c thc s chuyn i. M hnh qun l bng thng gm nhvy c gi l m hnh qun l bng thng tnh (xem hnh 2.1).

Hnh 2.1: M hnh qun l bng thng tnh2.2 iu khin lu lng vo2.2.1Gii thut thng ng th

Thng ng th l mt c ch iu khin lu lng vo da trn s xut hin cacc th trong thng, xem hnh 2.3.

Gii thut thng th c trnh by nh sau, xem hnh 2.4:Mi th c a vo thng vi tc 1/r giy. Thng ch c th cha ti a b th. Mt th s b hu b nu khi th n gp lc

thng y.Khi mt gi tin n byte truyn n, n th s c loi khi thng, sau gi tin s

c truyn qua.Nu s th cn trong thng nh hn n, gi tin s khng c truyn v c gi l

khng ng iu kin (non-conformant), th cng s khng b loi khi thng.

Hnh 2.3: K thut thng ng thGii thut cho php tc nh ti a b byte, nhng tc truyn gi tin ca h

thng b gii hn tc r. Cc gi tin khng ng iu kin c th c x l theo cccch sau:


6/12

6

- C th b hu- C th c xp hng v ch cho n khi th trong thng- C th c truyn qua, nhng c nh du l khng ng iu kin, v c th

b hu nu h thng mng trong tnh trng qu ti.

Hnh 2.4: Gii thut thng ng th2.2.2iu khin lu lng vo

iu khin lu lng vo l m bo ti nguyn mng khng c qu ti. Nicch khc, n phi m bo rng tng t l ng k s dng ti nguyn ca mi lung lu

lng truyn qua mi kt ni mng l khng ln hn dung lng ca kt ni. Phng trnhton hc biu din nh sau:

n

i

Ri

1

(1)

Trong , l dung lng kt ni tnh theo bit/giy (bits/second) v Ri l t l lulng ca lung th i.2.2.3Cc thnh phn iu khin lu lng vo

Cc gii thut iu khin lu lng vo c 4 thnh phn then cht sau y:Profile lu lngo lng lu lngiu kin chp nhnQuyt nh chp nhn

2.2.4Phn lp cc gii thut iu khin lu lng vo.

Hnh 2.5: Phn lp gii thut iu khin lu lng

19

Hnh 4.4: tr gi ca cc lp lu lng


7/12


8/12

8

u tin xc nh thi im truyn cc gi tin.Khng gian b m ni hu gi tin ti cng ra.

2.3.2Phn loi cc gii thut phn phi lu lng Cc gii thut hng i c phn chia trong hnh 2.8. Trong mt mi trng

nhiu hng i, cc gii thut phn phi lu lng ra chnh bao gm:

Hnh 2.8: Phn loi gii thut phn phi lu lng ra Hng i FIFO Hng i u tin (PQ) Hng i cng bng (FQ) Hng i theo lp (CBQ) Vng trn trng s thm ht (DWRR) Hng i trng s cng bng (WFQ) 2.4 nh gi hn ch2.4.1Hn ch ca cc k thut iu khin lu lng vo

Mt trong nhng thch thc ln nht ca iu khin lu lng vo trn mng IP lvic chia s ti nguyn mng mt cch hiu qu gia cc lung d liu nhy cm vi tr cchp nhn vo mng.

iu khin lu lng vo theo tham s truyn thng ch yu da trn cc m hnhthng k c t lung. Cc tham s thng c s dng bi cc lung c lng tinguyn cn thit. Thit b mng s dng cc c lng chp nhn hay t chi cc lungph thuc vo s sn sng ca cc ti nguyn c yu cu. Nhng vn vi phng phpny l cc ng dng thng rt kh m t chnh xc cc mu lu lng p dng. Trongmng IP hu ht lu lng thng rt a dng. V vy, m nhn c cc ti nguyn camkt, cc lung cung cp cc c lng tham s u t in th hin phn ng t rong trng hpxu nht. iu ny c th gy ra qu ti ng k trc ti nguyn mng.

Cc gii thut iu khin lu lng vo theo tham s c th c phn tch theocc phng php c th. Cc gii thut iu khin lu lng vo theo o lng c th cphn tch theo kinh nghim trn cc mng thc t hoc cc h thng m phng. Mc chca chng ta y khng phi l chn ra phng php tt nht m ch l a ra cc nhgi, khng ch da trn iu kin nh gi c s dng trong vic so snh cc gii thutiu khin lu lng vo theo o lng khc nhau m cn da trn cc nh ngha so snh ngha ca cc gii thut iu khin lu lng vo theo o lng. Phng php n gin nhtm bo tun theo cc cam kt y l cp pht ti nguyn p ng cc yu cuphng trng hp xu nht ca mi lung. Tuy nhin, vi cc ngun tng t bin, m hnhny s dn n hiu qu s dng mng thp.

17

Hnh 4.3: Chng giao thc Router trong Opnet Modeler

Cc giao din ca b nh tuyn c iu khin bi tin trnh ip_output_iface,vic iu khin lu lng vo c thc hin bi tin trnh ny. Th vin ip_qos_supportci t cc gii thut iu khin lu lng vo, cn th vin oms_qm ci t cc gii thutphn phi lu lng PQ, WFQ v CBQ.

Khi mt gi tin n giao din b nh tuyn, n c phn loi theo cu hnh trongi tng QoS. HmIpQosCarPolicyLimit() quyt nh vic chp nhn hoc loi b mt gi

tin.4.5 nh gi kt qu

Sau khi thc hin m phng, chng ta phn tch cc tiu ch cht lng dch v (tr gi, bin thin tr, t l mt gi) ca h thng cn c vo h thng cc bo co phntch kt qu m phng.4.5.1 tr gi

Qua hnh 4.3 chng ta thy tr gi gia cc lp lu lng khc nhau l khcnhau, tr gi ca lu lng nhy cm vi tr l lu lng video (class 3) c tr thpnht.


9/12

16

4.4.2Ci t h thng m phngH thng m ti nghin cu trn c ci t trong Opnet Modeler (version

10.0) nh hnh v 4.2.

Hnh 4.2: Ci t h thng m phng trn Opnet ModelerCc th vin nh ngha ng dng gm th vinApplication Definition (vit tt

lApp Def) v Profile Definition Definition (vit tt l Profile Def) .Th vin nh ngha cc k thut QoS l IP QoS Definition (vit tt lIP QoS).

y l ni ta c th nh ngha cc k thut QoS nh CAR, WFQ p ng cc yu cucho cc ni dung m phng.

Cc thit b mng gm cc my tnh trm, my tnh ch trin khai cc dch vmng v c bit l hai b nh tuyn Router_1 v Router_2 kt ni hai phn mng LAN cah thng li vi nhau.4.4.3Ci t cc gii thut qun l bng thng ng

Trong Opnet Modeler, mi b nh tuyn c thit k gm nhiu node theo kiuchng giao thc. Hnh 4.3 trnh by m hnh phn cp cc tin trnh ca b nh tuynRouter_1, ti b nh tuyn ny chng ta cn ci t cc gii thut iu khin lu lngnhm p ng cc yu cu QoS.

9

2.4.2Hn ch ca cc k thut phn phi lu lng raFIFO khng th gii quyt cng lc c ba vn cp pht bng thng, u tin

v khng gian b m. Tuy nhin, cho d cc gii thut iu khin lu lng c s dngbi cc ngun lu lng c x l hiu qu n u, th cc mng vi cc cng FIFO ukhng p ng c. Khi s dng FIFO, cc ngun lu lng x l km c th tiu tn tonb bng thng, cc ngun t bin c th gy tr cc lu lng quan trng, nhy cm vithi gian, phn lu lng quan trng c th b hu v phn lu lng ny khng c a

y vo hng i.PQ hiu qu trong mng tc cao, tr thp, bin thin tr thp, nhng n

cng i hi xy dng cc iu kin hp l nhm ngn chn tnh trng qa ti ng k trcti nguyn. Hn na, s dng PQ c th lm thiu ti nguyn cho cc lp dch v khc.

FQ to ra s cng bng bng cch cp pht lng bng thng bng nhau cho milung d liu, nhng s khng ph hp vi cc lung d liu c yu cu bng thng khcnhau. FQ cng nhy cm vi th t gi tin n.

WFQ rt hiu qu trong vic cung cp cc m bo dch v, nhng v n lm vicvi cc kt hp lung, nu mt lung d liu trong kt hp b i x km s lm nh hngn hot ng ca cc lung khc.

WRR hoc CBQ t phc tp hn do vy n mm do hn. Hn ch ca cc kthut ny n cp pht chnh xc lng bng thng cho mi lp dch v ch khi mi gi ti ntrong hng i c cng kch thc hoc khi kch thc gi tin quan trng c bit trc.

DWRR cng t tnh ton phc tp hn nh WRR v cp pht bng thng chnh xc

hn. Tuy nhin, n cng nh hng bi cc lung d liu kt hp nh trong WFQ v WRR. Mi phng thc cp pht l tnh v khng th sa i trng s theo cc iu kinlu lng.


10/12

10

Chng 3 QUN L BNG THNG NG3.1 Gii thiu chung3.1.1Yu cu pht trin m hnh qun l bng thng ng

Qua cc nh gi ny chng ta nhn thy cc k thut qun l bng t hng tnh luntn ti cc hn ch nh sau:

- Cp pht ti nguyn h thng mt cch cng nhc cho cc lp lu lng hay ccng dng, mc d trong thc t, yu cu bng thng ca cc ng dng c th thay i theothi gian. iu dn n vic tha ti nguyn ti cc thi im lu lng thp v thiu htti nguyn tai cc thi im lu lng cao.

- Vic cp pht ti nguyn cng nhc cng dn n s lng ph ti nguyn mngli, ti nguyn quan trng ca mng li (ti nguyn m chng ta ng xt y l bngthng ca h thng) khng c khai thc ti u.

- S bng n cc ng dng mi trn nn mng TCP/IP lm cho vic khai bo mt lu lng tr nn rt phc tp, iu ny tr nn c bit kh khn trong mi trng mnginternet.

khc phc cc hn ch ny, m hnh qun l bng thng m ti xut gil m hnh qun l bng thng ng hay cn gi l m hnh qun l bng thng thch nghi.3.1.2Gii thiu m hnh qun l bng thng ng

M hnh qun l bng thng ng m ti xut hot ng theo nguyn l ca h

thng phn hi mch ng (xem hnh 3.1).

AC

AC

AC

n v phnphi ti nguyn

1

2

m

w1

w2

wn

Hnh 3.1: M hnh qun l bng thng ng

3.2 Xy dng h thng qun l bng thng ng3.2.1Kin trc h thng qun l bng thng ng

M hnh ph hp cho cc b nh tuyn bin thc hin chc nng cng kt ni mtmng thuc mt vng qun tr vo mng chung nh internet (xem hnh 3.2).

Hnh 3.2: M hnh mng mt vng qun tr

15

- OPNET Modeler s dng phng php m hnh ho hng i tng v cc bson tho ho m phng cu trc cc h thng mng thc t v cc thnh phn mng,do chng ta c th nh x mt cch trc quan h thng thc t.

- OPNET Modeler h tr hu ht cng ngh v cu trc mng, n cho php chngta tr li mt cch t tin hu ht cc cu hi phc tp trong thc t. 4.3 Cc c trng ca Opnet Modeler

L b phn mm m phng hiu qu v linh hot nht trong lnh vc cng nghip,

OPNET Modeler c cc c trng sau:- Nn tng m hnh ho chuyn nghip, vi kh nng m phng y cc s kinri rc song song v tun t, m phng gii tch v lai ghp, c kh nng hot ng 64 bit.

- Mi trng ho trc quan nn c th m phng r rng cc h thng mngthc t, cc thit b, giao thc v ng dng.

- C kh nng m phng tt c cc m hnh kin trc mng.- C th tip nhn t ng thng tin kin trc mng t cc cng c, phn mm

khc.- C th truy cp vo chng trnh ngun cc th vin m hnh ho giao thc ph

bin trong mi trng cng nghip. - L mi trng c thit k m hnh ho cc giao thc s dng m hnh my

trng thi hu hn FSM, C/C++ v cc th vin m rng. - Bao gm cc cng c phn tch mng c tch hp trc tip vo mi trng

ho.

4.4

M phng h thng bng OPNET MODELER4.4.1M hnh h thng m phng

Hnh 4.1: Cu trc h thng mng m phngTheo kin trc mng trnh by trn hnh v 4.1, mi PC c kt ni n mt thit

b Switch bng kt ni Ethernet tc 100Mbps. Khng gian b m ti cc Switch cchia s cho mi lung d liu vo. Cc my trm t trong mng A bn tri v cc my cht trong mng B bn phi kt ni chia s E1 tc 2Mbps. Cc my trm hi nghi t xa,chng ta t vo hai mng A v B nhm phc v trao i thng tin video gia hai mng A vB. Kt ni E1 gia hai b nh tuyn bin A v B l kt ni c chai gia hai mng.


11/12

14

3.3.3Tm lc cc tham s phn hi

Tc cn thng th: Tham s ny th hin yu cu th ca mt lp lu lng chotrc. Tham s ny thay i trong khong [0,1]. Cng nhiu th b rt khi thng th gi trtc cn thng cng cao. Tc cn thng th cao hn th hin lp lu lng t n

profile c nh ngha ca n hoc l ang trong qu t rnh cp pht ti nguyn. Trong chai trng hp, tc cn thng l tham s quan trng ca gii thut iu khin lu lngvo thch nghi AAC, m bo rng chng hon ton sn sng.

Tc cn dch v: Tham s phn hi ny xc nh tc dch v c yu cuca mt lp lu lng. N nh hng trc tip n vic tnh ton kch thc hng i trungbnh v ngng trn ca hng i. Kch thc hng i trung bnh c tnh ton nh tronggiao thc RED. Vic tnh ton trung bnh di chuyn trng s hm m tng cng lm trncc thay i kch thc hng i, do n s ngn chn cc giao ng h thng tc thi.

Chng 4 M PHNG V KT QU4.1 Gii thiu

Nh chng ta bit, ba phng php chnh nh gi hot ng ca mt hthng l phn tch l thuyt, o lng v m phng. Vi mt h thng phc tp, rt nhiutham s nh h thng chng ta ang xt, phng php phn tch l thuyt l rt phc tp vphi a ra rt nhiu gi nh n gin h thng v kt qu c th khng chnh xc. s

dng phng php o lng, h thng chng ta cn phi c trin khai trn cc b nhtuyn bin v cc thit b u cui. iu ny i hi mt phng Lab vi y thit b, iuny rt kh thc hin trong iu kin thc t ti Vit Nam. 4.2 B phn mm m phng OPNET MODELER

Cc u im sau:- OPNET Modeler l mi trng cng nghip cho vic m hnh ho v m phng

cc h thng mng, cho php thit k, nghin cu cc h thng mng vin thng, cc ngdng, giao thc, thit b.

- OPNET Modeler c s dng bi hu ht cc t chc cng ngh uy tn hngu trn th gii trong vic h tr cng tc nghin cu, pht trin.

Gii thut 3: Tnh kch thc hng i trung bnh

ifli 0 then

il = (1 - Wq) x l + Wq x li

elsem = (thi gian hng i ri)/(thi gian truyn)

il = (1 Wq)m x

il

endif

11

Cc iu kin thit k h thng bao gm:Dung lng kt ni ca kt ni WAN hng ra l (bit/sec) v nh hn dung

lng ca kt ni LAN, do vy chng ta cn phi tnh ton vic cp pht t i nguyn cho hpl.

H thng qun l bng thng ng m chng ta xy c kin trc nh hnh 3.3.Trong :

r0, r1, r2, r3 ln lc l tc a th vo cc thng th 0, 1, 2, 3. B0, B1, B2, B3: ln lc l dung lng cc thng th 0, 1, 2, 3.W0, W1, W2, W3: ln lc l tc cn dch v (s c trnh by trong phn

4.2.2.2) ca cc hng i 0, 1 , 2, 3.

Hnh 3.3: Cu trc h thng qun l bng thng ngTheo h thng ca chng ta gm hai phn nh sau:

Phn iu khin lu lng vo:hot ng theo c ch thng ng th token bucket(trnh by trong mc 3.2.1 ca chng 3). Phn phn phi lu lng ra: hot ng theo gii thut qun l hng i theo lp.3.2.2Nguyn l hot ng ca h thng3.2.2.1 iu khin lu lng vo

Gi b i(t) l s th c sn trong thng i ti thi im t, v Bi l kch thc cathng. Bi c xc nh profile lu lng lp th i.

Tc cn thng th (bucket starvation rate) c nh ngha nh sau:

,/1)(i

Bi

bti

s mi 1

Tc phn phi th chun ho (normalized token distribution rate) c nh

ngha:

,

1

)(/)(

m

j

tj

si

sti

p mi 1

pi(t) xc nh tc rt cn th trong thng, nhm bo v, hn ch giao ngchng ta s dng mt hm trung bnh trng s lm trn tc cn thng th.

,ti

pti

p(t)i

p )()1()1( 10

Nu l bng thng ca cng hng ra chia s theo bit/sec tc th vo thng i tithi im t c th nhn c theo cng thc:

)()( ti

pti

r


12/12

12

3.2.2.2 Phn phi lu lng raGi Tli v Thi l cc ngng di v trn ca hng i, trong 1 0)

wi = qi /endif

endendif

Tom Tat Luan Van.pdf (Nguyen Van Tien)

Documents

Transcript of Tom Tat Luan Van.pdf (Nguyen Van Tien)