tieu luan red choke

8/10/2019 Tieu Luan RED CHOKe

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CHOKe Sci tin c chhng i ca RED

Dng Khc Hng Page 2

hiu hiu sut bng phn mm m phng mng NS-2 v phn mm phn tch ktquTraceGraph.

2. C chqun l hng i RED

RED (Random Ealy Detection) l c chkim sot hng i di dng githng bo vtrm ngun vtnh trng tc nghn bng cch cho ri gi tin sm vtrm ngun nhn bit qua time out hoc duplicate ACK trm ngun gimtc pht. Xc sut ri gi tin sm phthuc di trung bnh ca hng i vhai gi trngng minth v maxth .

T tng thut ton:

- Nu slng gi tin trong hng i nm gia cc gi trminth v maxth th

hy bgi tin mt cch ngu nhin ty theo mt hm xc sut p.

- Nu hng i cha t hn minthgi tin th thm gi tin mi vo hng i vxc sut hy bl 0.

- Nu hng i cha nhiu hn maxth gi tin th hy bnhng gi tin miv xc sut hy bl 1.

Cc tham s vo:

maxth: l gii hn ca ngng kch thc hng i cc i ,minth:l gii hn ca ngng kch thc hng i cc tiu

maxp: xc sut ri cc i

: l trng s hng i trong on [0,1], 0 1.

Khi cc gi tin bmt hng i tc l c du hiu bm btrn. V vyECN c thnhn ra tc nghn thng qua vic mt gi tin, gip ch cho vic nngcao hiu nng mng.

3. C chqun l hng i CHOKeci thin khnng RED mt ci tin ca RED c xut. Cth,

chng ta th hin mt thut ton qun l hng i hot ng tng tRED chkhc nhau vthut ton khi chn nhng gi tin cho ri l CHOKe, n gin


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Dng Khc Hng Page 3

l thc hin skhc bit gy bt li cho lung hng bng cch cho ri cc gi tinca lung .

tng c bn ca CHOKe l tbm FIFO sxl cc lung lu lng

hng . Khi mt gi tin n mt bnh tuyn xy ra tc nghn, CHOKe rt ra mtgi tin ngu nhin tbm FIFO v so snh n vi cc gi tin n. Nu chaiu thuc vcng mt lung lu lng th nh rt chai gi. Ngc li, cc gitin c la chn ngu nhin sc ginguyn vn, cc gi tin n c nhnvo bm vi mt xc sut m phthuc vo mc tc nghn. Do , cc gitin ca cc lung lu lng hng c gim nhiu hn so vi cc gi tin ca lunglu lng p ng.

M hnh thut ton:

AvgQsize : Chiu di hng i trung bnhmaxth: l gii hn ca ngng kch thc hng i cc iminth: l gii hn ca ngng kch thc hng i cc tiu

tng:

CHOKe tnh ton lp y trung bnh ca bm FIFO bng cch sdngtrung bnh chuyn ng theo cp snhn tng tnh RED. N cng nh duhai ngng trn bm, mt ngng ti thiu minthv mt ngng ti amaxth.


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Dng Khc Hng Page 4

Nu kch thc hng i trung bnh b hn min th, th mi gi tin n cchp nhn xp hng i vo bm FIFO v kt thc.

Ngc li, cc gi tin c rt ra ngu nhin thng i. Nu chai gi tin

u n tmt lung th tin hnh nh rt hai gi tin v kt thc.Ngc li nu gi tin t2 lung khc nhau m kch thc hng i trung

bnh b hn maxth th gi tin c gn mt xc sut p.

Nu kch thc hng i trung bnh t cc i maxthth nh rt gi miv kt thc.

4. M phng

thy c s ci tin c chqun l hng i CHOKe trong tiu lunny ti sdng phn mm m phng mng NS2 m phng cc c chqun lhng i RED v CHOKe.

S m phng

S gm 36 nt, trong :

+ 17 nt gi (8 nt TCP, 9 nt UDP);+ 17 Nt nhn (8 nt TCPShink, 9 nt NUL);

+ 2 nt trung gian;

Tht nt cchai to tc nghn gia ng tryn hai nt trung gian vi

Bandwidth = 1Mb/sec v Delay = 2 ms.

Cc ng truyn gia cc nt khc c Bandwitdh=1Mb/sec v Delay=5ms


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Dng Khc Hng Page 5


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Dng Khc Hng Page 6

Vi m hnh nh nhau vcng thng snh nhaui vi RED v CHOKe:limit_ 20 (gii hn kch thc ca s)

thresh_ 5 (gii hn nhnht ca ca kch thc hng i TB)

maxthresh_ 20.000000 (gii hn ln nht ca ca kch thc hng i TB)

mean_pktsize_ 500 (c lng kch thc gi tin trung bnh tnh bng byte)q_weight_ 0.002000 (trng shng i)

linterm_ 15.000000 (Gi trnghch o ca Maxp)

Kt qum phng RED trn NS-2 v c phn tch bng TraceGraph

Thng lng ca cc gi tin gi i, cc gi tin nhn v cc gi tin ri trong20 giy c thhin qua thsau:


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Dng Khc Hng Page 7

Cc kt quc c sau khi chy m phng RED

Kt qum phng c chqun l hng i REDSgi tin gi: 92799Sgi tin nhn: 12030Sgi tin mt: 80769Sgi tin bri: 80607


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Dng Khc Hng Page 8

Kt qu m phng CHOKe trn NS-2 v c phn tch bngTraceGraph

Thng lng ca cc gi tin gi i, cc gi tin nhn v cc gi tin ri trong

thi gian 20 giy c thhin qua thsau:


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Dng Khc Hng Page 9

Cc kt quc c sau khi chy m phng CHOKe

Kt qum phng c chqun l hng iSgi tin gi: 93115Sgi tin nhn: 21131Sgi tin mt: 80984Sgi tin bri: 80850Bng so snh cc kt qugia c chRED v CHOKe


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Dng Khc Hng Page 10

5. Kt lunKhi c stc nghn th:+ Cc lung lu lng p ng khi nhn c thng bo nghn sgim tcgi dliu;

+ Cc lung lu lng khng p ng vn tip tc gi d liu nh bnhthng;Dn n cc lung khng p ng chim bng thng nhiu hni vi RED chcho ri gi tin khi n khi sgi tin trong hng i vt

qu maxth cn i vi CHOKe nu gi tin n cng lung vi mt gi tin no c ly ra ngu nhin trong hng i th chai gi u bcho ri cn khi sgi tin trong hng i vt qu maxth th c chcho ri gi tin hon ton gingRED.

T l gi tin mt ca CHOKe (86.97%) t hn ng k so vi RED(87.04%).

Tlgi tin ri ca CHOKe (86.83%) t hn ng kso vi RED (86.86%).Nh vy scho ri sm gi tin ca CHOKe trnh cho hng i nhanh y

hn RED dn n s tc nghn xy ra i vi CHOKe chm hn RED lm chohiu sut ca CHOKe (13.03%) ln hn ng kso vi RED (12.96%).

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Ti liu tham kho

[1] Nguyn Kim Quc, V Thanh T - NH GI HIU NNG CA MT SC CHQUN L HNG I TCH CC DA TRN KCH THC HNGI V TI NP.

[2] Rong Pan, Balaji Prabhakar, Konstantinos Psounis - A stateless active queuemanagement scheme for approximating fair bandwidth allocation.

[3] Ao Tang, Student Member, IEEE, Jiantao Wang, and Steven H. Low, SeniorMember, IEEE - Understanding CHOKe: Throughput and Spatial Characteristics

tieu luan red choke

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