GVHD :Th.s Ng c Thun Nhm : 9Trn Vn Mnh Nguyn Nam D Phm Tun Anh L Th Kim Dung Nguyn Hng Qun Nguyn Thnh Chung

CHUYN MCH GI

*Cng ngh chuyn mch

Contents1. Hn Ch Ca Chuyn Mch Knh2. K thut Ca Chuyn Mch Gi3. Cng Ngh Chuyn Mch IP4. Cng Ngh Chuyn Mch ATM5. DEMO nh Tuyn Dng OSPF

Hn ch Ca Chuyn Mch KnhS dng bng thng khng hiu qu : rng bng thng c nh 64kbpsKnh dnh ring cho 1 cuc giTnh an ton :Tn hiu thoi truyn trn 1 ng duy nht nn d b nghe trmKh nng m rng kmThit b 2 u phi chy cng tc

Hn ch ca chuyn mch knhHn ch ca chuyn mch knhChuyn mch knh ch truyn trn 1 ng c nh

Chuyn mch giKhi nim : Mng chuyn mch gi (packet switching) l truyn d liu dng nhng khi nh,ring bit gi l gi tin (packet)Da trn a ch ch cha trong packet pha nhn,cc gi tin s c lp rp li theo th t thch hp thnh 1 thng ip

c im ca chuyn mch giGim c tr ti cc node trong mngX l li v sa li hoc truyn li gi nhanh hn so vi chuyn mch bn tin Do gim c lng thng tin cn truyn li,gim tc nghn v tng tc truyn tin cng nh kh nng phc v ca mngC th nh tuyn cho tt c cc gi theo cc giao thc khc nhau

Cc thnh phn ca chuyn mch giMng chuyn mch gi gm cc thnh phn c bn sau y :Trm (station)Nt mng (Node)Cc ng truyn dn (Link)

K thut chuyn mch giCc bn tin cn truyn c chia ct thnh cc thnh phn nh hn gi l gi tinMi gi li c a thm phn iu khin mng c th nh tuyn gi n ch.Nguyn tc chuyn mch l ti tng nt gi c nhn,lu tm v chuyn tip ti nt tip theo cho n khi n ch cui cng

K thut chuyn mch giB1 : Phn on cc gi pha phtB2 : nh tuyn cc giB3 : Ti hp gi pha thuChuyn Mch Gi

Nguyn l ca chuyn mch gi

K thut chuyn mch giTy thuc vo giao thc truyn thng m c th c nhiu mc phn chia bn tin thnh cc gi c chiu di khc nhau.Ngoi nhng thng tin c ct t bn tin,gi cn c chn thm cc phn u (tiu ) v ui phc v cho vic nh tuyn qua mng

K thut chuyn mch giTrong mng chuyn mch gi cc gi tin c chuyn qua mng t nt ny ti nt khc theo nguyn l Lu m v pht chuyn tip.Mi nt sau khi thu mt gi s tm thi lu gi mt bn sao ca gi vo b nh m cho ti khi pht chuyn tip gi ti nt tip theo hoc ti trm ca ngi s dngChuyn mch gi c th p ng c yu cu hot ng truyn tin mt cch nhanh chng,k c khi c s hng hc mt phn hay nhiu tnh nng khc ca mng

K thut chuyn mch gi Lc d liu (Datagram)2 phng php Mch o(Virtual Circuit) K thut chuyn mch gi s dng 2 phng php tiu biu chuyn cc lung gi t ngun ti ch

Chuyn gi theo DatagramMi gi c x l c lpCc gi c th i theo bt c ng thch hp noCc gi c th n ch khng theo th t giCc gi c th tht lc trn ng iBn nhn phi sp xp li cc gi mt trt t v khi phc cc gi tht lc

Chuyn gi theo DatagramPhng php Datagram khng c thit lp v gii phng kt niDo giao thc thng tin ca Datagram cn c tn l giao thc phi kt ni (connectionless)

Chuyn gi theo DatagramGi s rng trm A c 3 bn tin 1,2,3 cn gi n B.Trm A truyn s liu n nt 4 (chia gi).Nt 4 c th to tuyn gi qua nt 5 hoc 3

Chuyn gi theo Virtual Circuitng i c to trc khi gi cc gi d liuCc gi yu cu cuc gi v chp nhn cuc gi c dng kt ni (handskare)Mi ng i c gn mt s ID Mi gi cha ID ca ng i thay v a ch my ch Khng cn tm ng cho tng ging i khng dnh ring

Chuyn gi Virtual Circuit

Chuyn gi theo Virtual CircuitTrc khi gi c chuyn i th c 1 gi gi l c hiu c gi t nt gc,trong cha a ch nt gcC hiu ny s chy qua cc nt,i n u n t hng chim kt ni qua nt

Chuyn gi theo Virtual CircuitKnh o VC gn ging nh chuyn mch knh v knh o c gii phng khi kt thc qu trnh chuyn tinCng 1 thi gian th mt PSE c th c nhiu VC n 1 PSE khc

Chuyn mch gi theo Virtual Circuit

Vn kch thc giGi s mch o t X n Y qua nt a,bBn tin gm 30 octetThm 3 octet gn u giNu ton b bn tin gi nh1 gi n 33 octet Times truyn l 99 vtg (33 x 3)Gi chia lm Data lm 2 Mi gi gm 15 octet thc v 3 octet tiu Times = 72

Vn kch thc giMt vn trong chuyn mch gi l kch thc gi c s dng trong mng c mi quan h cht ch gia kch thc gi v thi gian truyn dn Phi thit k gi sao cho c di thch hp m bo truyn gi nhanh nht

ng dng ca chuyn mch giGO ONX25CIRCUIT ATM MPLS

Mng X25X.25 l mt dch v mng din rng, ra i vo nhng nm 1970. Mc ch ban u ca n l kt ni cc my ch ln (mainframe) vi cc my trm (terminal) xa . u im ca X.25 so vi cc gii php mng WAN khc l n c c ch kim tra li tch hp sn .

Mng X25Chn X.25 nu bn phi s dng ng dy tng t hay cht lng ng dy khng cao .X.25 l chun ca ITU-T cho truyn thng qua mng WAN s dng k thut chuyn mch gi qua mng in thoi .

Mng X25

Mng X25

Thut ng X.25 cng cn c s dng cho nhng giao thc thuc lp vt l (physiscal) , lp lin kt d liu (data link) v lp mng (network) to ra mng X.25 .

Mng X25

Theo thit k ban u, X.25 s dng ng dy tng t to nn mt mng chuyn mch gi, mc d mng X.25 cng c th c xy dng trn c s mt mng s.

M hnh mng x25

X25Hot ng 3 lp cui.Kim sot li ,lung tt.NhngBng thng c nh (64kbps)Dung lng qu thp ,khng ph hp vi nhu cu s dng dch v a mi trng.Phi thit lp cc mng chuyn mch gi nhanh. ( FR ,ATM ,)

Cng ngh chuyn mch IPKhi nim :nh tuyn bn tin 1 cch c lpC cu nh tuyn v chuyn tin linh ng,hiu qu,phi kt niIP l giao thc chuyn mch gi,c tincy cao v kh nng m rng caoKhuyt imIP khng h tr cht lng dch v (QoS)Vic iu khin lu lng rt kh thc hindo phng thc nh tuyn theo tng chng

Cng ngh chuyn mch IPKhi nim nh tuyn bn tin mc cch c lp.C cu nh tuyn v chuyn tin linh ng,hiu qu,phi kt niIP l mt giao thc chuyn mch gi c tin cy cao v kh nng m rng caoKhuyt imIP khng h tr cht lng dch v (QoS)Vic iu khin lu lng rt kh thc hin do phng thc nh tuyn theo tng chng

Cng ngh chuyn mch IPHnh mng IP

Telephone

Computer

Cloud

Printer

Workstation

Private Network

Private Network

Private Network

Private Network

Private Network

Private Network

Router

Router

Router

Router

Router

Cng ngh chuyn mch IP

IP Header1Frame HeaderIFrame HeaderIIP Header1

Data Stream

Data

Data

Data

Data Stream

Data Stream

Data Stream

Data Stream

Data Stream

Data Stream

Data

Data Stream

Data

Data

Data

Data Stream

Data Stream

Data Stream

Data Stream

Data Stream

Data Stream

Data Stream

Cc phng php nh tuynStatic routing:Ngi qun tr mng thit lp 1 con ng i mc nh t trc cc d liu ch c truyn trn ng i .

Dynamic routing:l qu trnh trong cc b nh tuyn t ng iu chnh theo s thay i m hnh mng hoc lu lng lu thng trn mng.

Default routing:l 1 dng c bit ca static routing.

Cc giao thc nh tuyn truyn thngDistance Vector (nh tuyn theo khong cch vector):Cc router gi nh k bng nh tuyn cho cc router lng ging.Khi nhn c th cc router ny s update bng nh tuyn v li gi cho cc router khc trong mng.Link State (nh tuyn theo trng thi kt ni):s dng thut ton tm ng ngn nht trc SPF. Phng php ny i hi x l nhiu hn distance vector nhng kim sot hu ht qu trnh nh tuyn v p ng nhanh nhng thay i.Hybrid : l phng php kt hp nhng c im tt nht ca 2 phng php trn.

nh tuyn trn mng InternetMng Internet l mt mng rng ln .N bao gm cc Domain khc nhau.

S nh tuyn bn trong cc domain gi l nh tuyn trong.

S nh tuyn gia cc Domain khc nhau gi l nh tuyn bin.

nh tuyn BGP (Border Gateway Protocol)L giao thc nh tuyn cng bin trn Internet dng vi TCP/IPBGP tch ly cc thng tin cn thit cho nh tuyn (chi ph ,s hop, an ton ng i) ri sau mi trao i vi cc domain khc .=> Gim thiu bng thng trao i khng cn thit gia cc domain vi nhau.

Cng ngh chuyn mch ATMATM (Asynchronous Transfer Mode) phng thc truyn khng ng b s dng k thut chuyn mch gi cht lng cao.

ATM kt hp tt c nhng li th ca k thut chuyn mch knh v chuyn mch gi vo mt k thut truyn thng duy nht.

S dng cc gi c nh gi l cc t bo, n c th truyn ti mt hn hp cc dch v bao gm thoi, hnh nh, s liu, c th cung cp cc bng thng theo yu cu.

c imATM c mt c im rt quan trng l nhm mt vi knh o (VCI) thnh mt ng o (VPI) p dng phng thc chuyn mch a ch (Address) cn gi l chuyn mch nhn (Label) nhm gip cho vic nh tuyn c d dng.

VCI: Virtual Channel IdentifierVPI: Virtual Path Identifier

Quan h gia cc kt ni trong ATM

c imV kha cnh truyn dn, ATM l mt phng thc ghp knh khng ng b s dng cc gi c kch thc nh v c nh l 53 bytes gi l t bo ATM (ATM cell).

Cc t bo nh cng vi tc truyn ln s lm cho tr truyn v bin ng tr gim nh i vi cc dch v thi gian thc, ngoi ra kch thc nh cng s to iu kin cho vic hp knh tc cao c d dng hn.

Kin trc mng ATM

M hnh giao thc chun ca B-ISDN

Mt phng qun l Qun l lp (Layer Managerment) Qun l mt phng (Plane Managerment).Nhim v l to ra s phi hp gia cc mt phng khc vi nhau. Qun l mt phng khng c cu trc phn lp, qun l lp c cc lp khc nhau nhm thc hin cc chc nng qun l c lin quan ti cc ti nguyn v thng s nm cc thc th c giao thc.

Mt phng ngi s dng

C nhim v truyn cc thng tin ca ngi s dng t im A n im B trn mng.

Cc c ch nh iu khin lung, iu khin tc nghn, chng li u thc hin ti mt phng ny, mt phng ny cng c cu trc phn lp.

Mt phng iu khin Lp bc cao (High Layer): Tng ng vi 3 lp trn cng ca m hnh OSI.Lp vt l (Physical Layer): ng vi lp 1 (lp vt l) trong m hnh OSI.Lp ATM (ATM Layer): c th coi nh nm ti l di ca lp 2 (lp truyn d liu) trong m hnh OSI.Lp AAL (ATM Adaptation Layer): c nhim v thc hin vic kt ni vi cc giao thc ca lp cao hn.

T bo ATM (cell)UNI Cell FormatNNI Cell Format

nh dng headerGFC ( General Flow control) l trng iu khin lung chung. VPI (Virtual Path Identyfier) v VCI ( Virtual Channel Identyfier) l hai trng nh tuyn cho cc t bo trong qu trnh chuyn mch.PT ( Payload Type) l trng ti thng tin xc nh xem t bo ny mang thng tin khch hng hay thng tin iu khin. N cng xc nh qu ti ca t bo thng tin khch hng.

nh dng headerCLP ( Cell Loss Prioryti) l trng u tin b t bo dng ch ra kh nng cho php hoc khng cho php b cc t bo khi c hin tng qu ti xy ra. + Nu cc t bo c CLP = 0 th c mc u tin cao. + Nu cc t bo c CLP = 1 th c mc u tin thp.HEC (Header Error Check) l trng kim tra li phn tiu . N dng pht hin li ghp bit v sa li cho ng cc li ghp bit n .

ATM Network

Trong nhng nm gn y,ngnh cng nghip Vin Thng v ang tm mt phng thc chuyn mch mi c th phi hp u im ca IP (nh c cu nh tuyn ) v ca ATM (nh thng lng chuyn mch)Cng ngh MPLS ra iVic nh tuyn cc gi da trn cc nhn c gn cho mi giH tr nhiu giao thc khc nhauCho php chuyn ti gi rt nhanh trong mng li v nh tuyn tt mng bin bng cch da vo nhn

Chuyn mch nhn a giao thc MPLS

So snh gia cc cng ngh:*

So snh gia cc cng ngh*

Cng nghIPATMMPLS

So snh gia chuyn mch knh v gi

www.dientuvienthong.net

******