TRUNG TM NIIT VNH LONG

Disuss the merits , demerits and usage of five network topologies used for network connections :

Star : Bi Minh Ho

Ring : Nguyn Hunh Phng Trc

Bus : T Th Thanh Tuyn

Mesh : Phan Quc Huy Start Date : 10/6/2008 End Date : 2/7/2008

CERTIFICATE

This is certify that this report titled Cu Trc Mng Lin Kt embodies the original work done by Tuyn , Ho , Trc , Huy in partial fulfillment of the course requirement at NIIT.

Coordinator: HYNH B MN

Mng cc b (LAN) l h truyn thng tc cao c thit k kt ni cc my tnh v cc thit b x l d liu khc cng hot ng vi nhau trong mt khu vc a l nh nh mt tng ca to nh, hoc trong mt to nh.... Mt s mng LAN c th kt ni li vi nhau trong mt khu lm vic.

Cc mng LAN tr nn thng dng v n cho php nhng ngi s dng (users) dng chung nhng ti nguyn quan trng nh my in mu, a CD-ROM, cc phn mm ng dng v nhng thng tin cn thit khc. Trc khi pht trin cng ngh LAN cc my tnh l c lp vi nhau, b hn ch bi s lng cc chng trnh tin ch, sau khi kt ni mng r rng hiu qu ca chng tng ln gp bi tn dng ht nhng u im ca mng LAN ngi ta kt ni cc LAN ring bit vo mng chnh yu din rng (WAN). Cc kiu (Topology) ca mng LANTopology ca mng l cu trc hnh hc khng gian m thc cht l cch b tr phn t ca mng cng nh cch ni gia chng vi nhau. Thng thng mng c 3 dng cu trc l: Mng dng hnh sao (Star Topology), mng dng vng (Ring Topology) v mng dng tuyn (Linear Bus Topology). Ngoi 3 dng cu hnh k trn cn c mt s dng khc bin tng t 3 dng ny nh mng dng cy, mng dng hnh sao - vng, mng hn hp,v.v....

Mng dng hnh sao (Star topology) Mng dng hnh sao bao gm mt trung tm v cc nt thng tin. Cc nt thng tin l cc trm u cui, cc my tnh v cc thit b khc ca mng. Trung tm ca mng iu phi mi hot ng trong mng vi cc chc nng c bn l: Xc nh cp a ch gi v nhn c php chim tuyn thng tin v lin lc vi nhau. Cho php theo di v x l sai trong qu trnh trao i thng tin. Thng bo cc trng thi ca mng... Trong cu hnh mng Star (hnh sao), cc my tnh c ni cp vo mt thit b gi l HUB (tc u ni trung tm). Tn hiu c truyn t my tnh gi d liu qua HUB n tt c cc my tnh trn mng. Cu hnh ny bt ngun t thi k u, khi vic tnh ton da trn h thng cc my tnh ni vo mt my chnh trung tm.

Mng Star cung cp ti nguyn v ch qun l tp trung. Tuy nhin, do mi my tnh ni vo mt trung tm im, nn cu hnh ny cn rt nhiu cp nu ci t mng quy m ln. Ngoi ra, nu trung tm b hng th ton b mng cng b t. Trng hp mt my tnh hoc on cp ni my tnh vi HUB b hng trn mng Star, th ch my tnh mi khng cn c th gi hay nhn d liu mng. Cc my tnh cn li trn mng vn hot ng bnh thng. Cc u im ca mng hnh sao: Hot ng theo nguyn l ni song song nn nu c mt thit b no mt nt thng tin b hng th mng vn hot ng bnh thng. Cu trc mng n gin v cc thut ton iu khin n nh. Mng c th m rng hoc thu hp tu theo yu cu ca ngi s dng.

ng theo nguyn l kt ni song song nn nu c mt thit b no mt nt bt k b hng th mng vn hot ng bnh thng, cc my cn li vn hot ng bnh thng.

L mt kiu mng c cu trc n gin, v tnh n nh cao d lp t.

Mng c th m rng hoc thu hp ty theo yu cu ca ngi s dng

Nhc im ca mng hnh sao: Kh nng m rng mng hon ton ph thuc vo kh nng ca trung tm . Khi trung tm c s c th ton mng ngng hot ng. Mng yu cu ni c lp ring r tng thit b cc nt thng tin n trung tm. Khong cch t my n trung tm rt hn ch (100 m). Nhn chung, mng dng hnh sao cho php ni cc my tnh vo mt b tp trung (HUB) bng cp xon, gii php ny cho php ni trc tip my tnh vi HUB khng cn thng qua trc BUS, trnh c cc yu t gy ngng tr mng. Gn y, cng vi s pht trin switching hub, m hnh ny ngy cng tr nn ph bin v chim a s cc mng mi lp.S m rng mng phi ph thuc vo kh nng ca thit b trung tm.

Nu thit b trung tm li th ton b mng s b t lit.

Khong cch ti a t cc nt ti trung tm b hn ch ( nh hn 100m).

Khi cc my kt ni thnh LAN th - Cc my c th dng chung mt ng dng no - C th trao i thng tin vi nhau d dng - C th dng chung cc thit b ngoi vi nh my in , CD ... - C th trun tin ti tt c cc my d dng

Vic kt ni cc my tnh vi mt dy cp c dng nh mt phng tin truyn tin chung cho tt c cc my tnh. Cng vic kt ni vt l vo mng c thc hin bng cch cm mt card giao tip mng NIC (Network Interface Card) vo trong my tnh v ni n vi cp mng. Sau khi kt ni vt l hon tt, qun l vic truyn tin gia cc trm trn mng tu thuc vo phn mm mng. Khi mt my mun gi mt thng ip cho my khc th n s dng mt phn mm trong my no t thng ip vo mt gi tin (packet) bao gm d liu thng ip c bao bc gia tn hiu u v tn hiu cui V dng phn mm mng gi gi tin n my ch NIC s chuyn gi tn hiu vo mng LAN, gi tn hiu c truyn i nh mt dng cc bit d liu Khi n chy trong cp chung mi my u nhn c tn hiu ny NIC mi trm s kim tra a ch ch trong tn hiu u ca gi xc nh ng a ch n, khi gi tn hiu i ti my c a ch cn n, ch my s sao gi tn hiu ri ly d liu ra khi gi tin v a vo my tnh.

Cu trc lin kt mng Ring (vng khp kn) ni cc my tnh trn mt vng cp, khng c u no b h. Tn hiu truyn i theo mt chiu v i qua tng my tnh. Khc vi Cu trc lin kt bus th ng, mi my tnh ng vai tr nh mt b chuyn tip khuch i tn hiu v gi n ti my tnh tip theo. Do tn hiu i qua tng my nn s hng hc ca mt my c th nh hng n ton mng. Mng dng vng (Ring Topology):

L c cu trc tng b phn mng trn mng truyn thng c vi hai b phn bn cnh n, tt c cc gi lu chuyn dc theo vng trong cng mt hng

- Mng dng ny, b tr theo dng xoay vng, ng dy cp c thit k lm thnh mt vng khp kn, tn hiu chy quanh theo mt chiu no .

-Cc my tnh c lin kt vi nhau thnh mt vng trn theo phng thc "mt im - mt im ", qua mi mt trm c th nhn v truyn d liu theo vng mt chiu v d liu c truyn theo tng gi mt. Mi gi d liu u c mang a ch trm ch, mi trm khi nhn c mt gi d liu n kim tra nu ng vi a ch ca mnh th n nhn ly cn nu khng phi th n s pht li cho trm k tip, c nh vy gi d liu i c n ch. u im: Khng tn nhiu dy cp, tc truyn d liu cao

Khng gy ch tc tuy nhin cc giao thc truyn d liu phc tp v nu c trc trc trn mt trm th cng nh hng n ton mng. Mng dng vng c thun li l c th ni rng ra xa Nhc im : ng dy phi khp kn, nu b ngt mt ni no th ton b h thng cng b ngng.

ng Dng: Cu trc dng li c s dng trong cc mng c quan trng cao m khng th ngng hot ng, chng hn trong cc nh my in nguyn t hoc cc mng ca an ninh, quc phng

Mng Bus cn c gi l mng "xng sng", l kiu hnh b tr trc tuyn, ni lin tt c cc my tnh trn mng hoc nhm lm vic theo mt hng. Tn hiu d liu c truyn n tng my tnh trn mng. Cc my tnh trn mng c ni vi nhau bng mt cable ng trc. Khp ni Barrel trn Net work Adapter Card s cho php cable ni trc tip vi tng my tnh; v nu c s dng Hub, cable s ni vi vi khp ni Barrel ca Hub.

Cu hnh mng BUS : L phng php ni mng vi tnh n gin v ph bin nht. Cu hnh mng bus bao gm mt dy cp n l ni tt c my tnh trong mng theo mt hng. Theo cch b tr hnh lang cc ng nh hnh v th my ch (host) cng nh tt c cc my tnh khc (workstation) hoc cc nt (node) u c ni v vi nhau trn mt trc ng dy cp chnh chuyn ti tn hiu. Tt c cc nt u s dng chung ng dy cp chnh ny. Pha hai u dy cp c bt bi mt thit b gi l terminator. Cc tn hiu v gi d liu (packet) khi di chuyn ln hoc xung trong dy cp u mang theo i ch ca ni n

My tnh trn mng bus giao tip bng cch gi d liu n mt my tnh xc nh v a d liu ln cp di dng tn hiu in t. My tnh giao tip trn mng bus gm 3 khi nim sau : Gi Tn Hiu: D liu mng hnh thi tn hiu in t c gi ti mi my tnh trn mng, tuy nhin thng tin ch c my tnh c a ch so khp vi a ch m ho trong tn hiu gc chp nhn. Mi ln ch c mt my c th gi thng ip. Di Tn Hiu : Do tn hiu, tc tn hiu in t, c gi ln ton mng nn d liu s i t u cp ny ti u cp kia. Nu tn hiu c php tip tc khng ngng, n s di quay tr li trong dy cp v ngn khng cho my tnh khc c gi tn hiu. Do tn hiu phi b chn li sau khi n c ng a ch ch. Terminator: Nhm ngn khng cho tn hiu di li, mt thit b c tn gi l terminator (in tr cui) c t mi u cp hp th cc tn hiu t do. Vic hp th tn hiu s lm thng cp v cho php my tnh khc c th gi tn hiu. Mi u cp trn mng phi c cm ci g . V d: c th cm u cp vo mt my tnh hay mt u dy ni m rng chiu di cp. Mi u cp h, tc u khng cm vo g c phi c chn li (bng Terminator) nhm trnh tn hiu di li. ng Dng :c dng ph bin trong cng nghip ch to nh t ng ho dy chuyn sn xut, gia cng, lp rp hoc mt s lnh vc ng dng khc nh t ng ho to nh, sn xut xe hi u im Ca Mng BUS : Dng dy cp t, d lp t Khng gii hn di cp D thit k , chi ph thp. tin cy cao. D m rng mng. Khng i hi Hub hoc thit b trung tm Khuyt im Ca Mng BUS : Tnh n nh km, ch mt nt mng hng l ton b mng b ngng hot ng. Theo tiu chun, tng s my tnh ni mng khng c vt qu 30

Tng chiu di ca cable khng c vt qu 185m..

Cc s c hng hc phc tp.

Tiu tn ti nguyn v b nh, v x l ca cc my trm Qun l phc tp S gy ra nghn mng khi chuyn lu lng d liu ln

Cung cp rt mhiu ng i trong vic truyn d liu gia hai my khi c mt ng b h mesh s d dng thit lp li ng mi d liu n c my nhn.Mt kh khn nht ca mesh l gi thnh v phi thit lp rt nhiu kt ni .

Cu trc lin kt dng li (Mesh): L Cu trc lin kt m mt thit b c ni ti tt c cc thit b khc trong mng. Thng dng trong cc kt ni mng li, to cc kt ni d phng khi mt kt ni b t.

Mng full mesh:

Cu hnh ny cho php cc thit b kt ni trc tip vi cc thit b khc m khng cn phi qua b tp trung nh Hub hay Switch.

u im: Cc thit b hot ng c lp, khi thit b ny hng vn khng nh hng n thit b khc D dng trin khai v lp t: mng li khng dy ny d dng ci t, c bit u im nhng ni cp khng ti c hoc kh trin khai.

An ton mng: vi kh nng tch hp cc tnh nng bo mt nh chng thc mng truy cp, m ha d liu ng truyn, cng ngh Mesh c tnh nng bo mt cao.

Cng nhiu ngi s dng cng ngh Mesh, gi trung bnh cho mi ngi s dng s thp i ng k trong khi gi nng cp c s h tng mng rt thp. Mng Mesh s mang li li nhun ng k cho cc nh khai thc bi tnh hiu qu kinh t ca n.

Nhc im: Tiu tn ti nguyn v b nh, v x l ca cc my trm Qun l phc tp

ng Dng:

Cng ngh Mesh khng nhng mang li thun tin trong vic trin khai lp t m cn tit kim kinh ph u t, khai thc. n nay, cng ngh WLAN ch yu c lp t trong cc ta nh, cc qun caf, sn bay, trng hc, cc c s y t, bnh vin v cc c quan, nh my. Vi cng ngh Mesh ny, cc nh khai thc c th d dng cung cp cc dch v khng dy bng rng vi chi ph u t v khai thc thp, ng thi c th ph sng din rng nhng ni cng cng, khch sn ln v c thnh ph ln.

TI

BUS

MESH

STAR

RING

GING VIN : HUNH B MN

LP : B0800013

NHM: 4

THNH VIN : TRC , TUYN, HO ,HUY

NM: 2008

- 15 -