Chuyn : K thut chuyn mch GVHD: TS.L Nht Thng

Chuyn : K thut chuyn mch GVHD: TS.L Nht Thng

Chuyn : K thut chuyn mch GVHD: TS.L Nht Thng

LI NI UCng vi s pht trin ca t nc, nhng nm gn y cc ngnh cng nghip u pht trin mnh m, v ngnh cng nghip vin thng cng khng l ngoi l. S ngi s dng cc dch v mng tng ng k, theo d on con s ny ang tng theo hm m. Ngy cng c nhiu cc dch v mi v cht lng dch v cng c yu cu cao hn. ng trc tnh hnh ny, cc vn v mng bt u bc l, cc nh cung cp mng v cc nh cung cp dch v cng c nhiu n lc nng cp cng nh xy dng h tng mng mi. Nhiu cng ngh mng v cng ngh chuyn mch c pht trin, trong s chng ta phi k n cng ngh chuyn mch nhn (MPLS l tiu chun). MPLS cng ang c nghin cu p dng nhiu nc, Tng cng ty BCVT Vit Nam cng p dng cng ngh ny cho mng th h k tip NGN.

ng trc s pht trin nhanh chng ca cng ngh chuyn mch nhn a giao thc MPLS, vic tm hiu cc vn v cng ngh MPLS l vn quan trng i vi sinh vin. Nhn thc c iu , chuyn mn chuyn mch Cng ngh MPLS/GMPLS v ng dng gii thiu v qu trnh pht trin dch v cng nh cng ngh mng dn ti MPLS, tm hiu cc vn k thut ca cng ngh, v ng dng ca cng ngh MPLS trong mng th h k tip NGN ca Tng cng ty BCVT Vit Nam. B cc ca n gm 3 chng. Chng I : Gii thiu cng ngh MPLS

Chng II : Gii thiu cng ngh GMPLS

Chng III : ng dng ca cng ngh MPLS / GMPLSCng ngh MPLS l cng ngh tng i mi m, vic tm hiu v cc vn ca cng ngh MPLS i hi phi c kin thc su rng, v lu di. Do vy n khng trnh khi nhng sai st. Rt mong nhn c s ph bnh, gp ca cc thy c gio v cc bn.

Xin gi li cm n chn thnh ti TS. L NHT THNG, ngi tn tnh hng dn nhm chng em trong sut qu trnh lm chuyn ny.

THUT NG VIT TTATM

Asynchronous Transfer ModeCh truyn dn khng ng b

ARPAddress Resolution ProtocolGiao thc phn gii a ch

ATMARPATM Address Resolution ProtocolGiao thc phn gii a ch ATM

BGPBorder Gateway ProtocolGiao thc cng ng bin

CoSClass of ServiceLp dch v

CLIPClassical IPIP trn ATM

CRConstrained Routingnh tuyn cng bc

CR-LDPConstrained Routing-LDPnh tuyn cng bc-LDP

CR-LSPConstrained Routing-LSPnh tuyn cng bc-LSP

CSPFConstrained SPFSPF cng bc

DiffServDifferentiated ServiceCc dch v c phn bit

DLCIData Link Connection IdentiferNhn dng kt ni lin kt d liu

ERExplicit Routingnh tuyn hin

FRFrame RelayChuyn tip khung

FECFowarding Equivalent ClassLp chuyn tip tng ng

IETFInternet Engineering Task ForceNhm tc v k thut Internet

IPInternet ProtocolGiao thc Internet

IntServIntegrated ServiceCc dch v c tch hp

LANLocal Area NetworkMng cc b

LANELAN EmulationM phng LAN

LDPLabel Distribution ProtocolGiao thc phn b nhn

LERLabel Edge Router Router bin nhn

LIBLabel Information BaseC s thng tin nhn

LSPLabel Switched Pathng dn chuyn mch nhn

LSRLabel Switch Router Router chuyn mch nhn

MGMedia GatewayCng a phng tin

MPLSMultiprotocol Label SwitchingChuyn mch nhn a giao thc

MPOAMultiprotocol Over ATMa giao thc trn ATM

NGNNext Generation NetworkMng th h k tip

NHRPNext Hop Resolution ProtocolGiao thc phn gii chng k tip

OSPFOpen Shortest Path FirstGiao thc ng i ngn nht u tin

PIDProtocol IdentifierNhn dng giao thc

PNNIPrivate Network-Network InterfaceMng ring o

QoSQuality of ServiceCht lng dch v

RESVResevationBn tin dnh trc

RFCRequest For CommentYu cu kin

RSVPResource Resevation ProtocolGiao thc dnh trc ti nguyn

SGSignaling GatewayCng bo hiu

SPFShortest Path Firstng i ngn nht u tin

STMSynchronous Transmission ModeCh truyn dn ng b

SVCSignaling Virtual CircuitKnh o bo hiu

TCPTransission Control Protocol Giao thc iu khin truyn dn

TGW Traffic GatewayCng lu lng

TLVTime To LiveThi gian sng

TLVType-Leng-ValueKiu-Chiu di-Gi tr

ToSType of ServiceKiu dch v

UDPUser Datagram ProtocolGiao thc lc d liu

VCVirtual CircuitKnh o

VCIVirtual Circuit IdentifierNhn dng knh o

VNPTVietnam Post & TelecommunicationsTng cng ty BCVT Vit Nam

VPVirtual Pathng o

VPNVirtual Private NetworkMng ring o

VPIVirtual Path IdentifierNhn dng ng o

WANWide Area NetworkMng din rng

DANH MC HNH V

Hnh 1.1M hnh chuyn mch nhn

Hnh 1.2Lin kit d liu l ATM

Hnh 1.3Lin kt d liu Frame - relay

Hnh 1.4Nhn trong Shim gia lp 2 v lp 3

Hnh 1.5C cu bo hiu

Hnh 1.6Mng MPLS trong hot ng ch ng khung

Hnh 1.7V tr ca nhn MPLS trong khung lp 2

Hnh 1.8Mng MPLS trong ch hot ng t bo

Hnh 1.9Trao i thng tin gia cc LSR cn k

Hnh 2.1Mt s li xy ra trong GMPLS

Hnh 3.1Mng my tnh in hnh cch y 16 nm

Hnh 3.2Mng Frame relay c trng

Hnh 3.3M hnh mng Extranet

Hnh 3.4nh hng mng NGN ca VNPT

Hnh 3.5Cu trc mng MAN E in hnh

Hnh 3.6T chc mng GMPLS Metro theo m hnh chng ln

Hnh 3.7T chc mng GMPLS Metro theo m hnh ngang hng

Hnh 3.8T chc mng GMPLS Metro theo m hnh lai ghp

Hnh 3.9Cc khuyn ngh ca ITU T v ASON

CHNG I: GII THIU CNG NGH MPLS1.1 Cng ngh ATM v IP.

1.1.1. Cng ngh ATM ATM l cng ngh chuyn mch hng kt ni, hai h thng phi thit lp ng truyn dn trc khi qu trnh truyn thng tin din ra.

Chc nng iu khin chp nhn vic kt ni CAC (Connection Addmission Control) m bo rng cc ti nguyn lin quan n kt ni hin ti s khng c a vo s dng cho cc kt ni mi. iu ny buc mng phi duy tr trng thi ca tng kt ni (bao gm thng tin v s tn ti ca kt ni v ti nguyn m kt ni s dng) ti cc nt m c tn hiu i qua.

Vic la chn tuyn c c thc hin da trn cc yu cu v QoS i vi kt ni v da trn kh nng p ng yu cu .

T c ch truyn tin ta thy mng hng kt ni thch hp vi:

Cc ng dng yu cu phi m bo QoS mt cch nghim ngt.

Cc ng dng c thi gian kt ni ln.i vi cc ng dng c thi gian kt ni ngn hn th m hnh hng kt ni dng nh khng thch hp do thi gian thit lp kt ni cng nh t l phn thng tin mo u li qu ln. Vi loi lu lng nh vy th mi trng phi kt ni vi phng php ng tuyn n gin, trnh phi s dng cc giao thc bo hiu phc tp s ph hp hn.

1.1.2. Cng ngh IP

Vi c s h tng hng kt ni ATM, cc gi tin lun phi i theo mt tuyn c nh c xc nh trc. Vi mi trng ny, khng th no nh tuyn gi tin mt cch c lp.

Trong mi trng phi kt ni truyn thng, khng phi s dng cc bn tin bo hiu thit lp cc kt ni, phng th chuyn tin l tng chng mt.

Tt c cc gi tin c chuyn i da trn quyt nh nh tuyn trong bng nh tuyn. B nh tuyn kim tra tng gi tin v v chuy gi tin theo hng c ti nguyn da theo quyt nh trong bng chuyn tin. Cc b nh tuyn x l tt c cc gi tin nh nhau v c th hu b tt c cc gi tin m khng cn bt k thng bo no cho c hai bn gi v nhn. Chnh v vy, IP ch cung cp dch v vi hiu qu truyn dn tt nht ch khng thch hp cho cc dch v c yu cu nghim ngt v QoS.

Tuy nhin m hnh phi kt ni cng c nhng u im nht nh ca n:

Kh nng dnh tuyn gi tin mt cch c lp.

C cu nh tuyn v chuyn tin n gii, hiu qu hn m hnh kt ni, rt ph hp vi cc ng dng c thi gian kt ni ngn.

1.1.3. S kt hp cng ngh ATM v IP - MPLSTrong nhng nm gn y, ngnh vin thng v ang tm mt phng thc chuyn mch c th phi hp u im ca ATM v IP.T nhng phn tch trn ta c th thy ph hp vi mng a dch v th c hai cng ngh ATM v IP u phi c nhng thay i. C th l a thm kh nng phi kt ni vo cng ngh ATM v kh nng hng kt ni vo cng ngh IP.

Phng php ny i hi c mt chi ph rt ln. Mt khc, cc thit b chuyn mch n gin hn so vi b nh tuyn, nn mt gii php khc cho mng a dch v l xy dng trn cc thit b chuyn mch.

Gii php ny tch ring hai chc nng nh tuyn v chuyn tin, kt qu l se gm hai phn t mng:

Mt s t cc b nh tuyn phc tp t tin vi kh nng nh tuyn mnh c t bin mng.

Cc thit b chuyn mch n gin r tin c t bn trong mng vi chc nng chuyn tip gi tin lp 3.

Nh vy, gii php ny chnh l s kt hp gia kh nng iu khin lung, truyn tc cao, cht lng dch v QoS ca thit b chuyn mch ATM vi kh nng nh tuyn mm do ca cng ngh IP.

1.2. Gii thiu chungCng ngh MPLS (Multi Protocol Label Switching Chuyn mch nhn a giao thc) l kt qu pht trin ca nhiu bin php chuyn mch IP s dng c ch hon i nhn nh ca ATM tng tc truyn gi tin m khng cn thay i cc giao thc nh tuyn IP.

MPLS chia chc nng ca router IP thnh hai phn ring bit: chc nng chuyn gi tin v chc nng iu khin.

- Phn chc nng chuyn gi tin gia cc router IP: s dng c ch hon i nhn nh ca ATM. K thut hon i nhn v bn cht l vic tm nhn ca cc gi tin trong mt bng cc nhn xc nh tuyn ca gi v nhn ca n. Cc router s dng thit b ny gi l b nh tuyn chuyn mch nhn LSR (Label Switching Router).

- Phn chc nng iu khin ca MPLS bao gm cc giao thc nh tuyn lp mng vi nhim v phn phi thng tin gia cc LSR, th tc gn nhn chuyn thng tin nh tuyn thnh cc bng nh tuyn cho vic chuyn mch.

MPLS c th hot ng c vi cc giao thc nh tuyn Internet khc nh OSPF (Open Shortest Path First) v BGP (Border Gate Protocol).

Do MPLS h tr vic iu khin lu lng v cho php thit lp tuyn c nh nn vic m bo cht lng dch v l hon ton kh thi. MPLS l cng ngh chuyn mch IP c nhiu trin vng. Vi c cu nh tuyn ca mnh, MPLS cc kh nng nng cao cht lng dch v ca mng IP truyn thng. 1.2.1. Hot ng v m hnh1.2.1.1. M hnh ca chuyn mch nhn

M hnh chuyn mch nhn l c ch ch yu trin khai trong mt phng chuyn tip d liu t ngun ti ch. Mng MPLS ch yu da vo m hnh ATM, FR v k thut chuyn mch nhn.Trao i nhn c nhiu u im so vi nh tuyn Hop by Hop c trin khai trong mng IP thng thng. N n gin v hiu qu hn. Vic phn tch gi ch c thc hin nt cng. Trao i nhn nhanh hn v vic hot ng n gin l nhn ra nhn v nh x n vo gi tr nhn tip theo. Nt bin ra nhn ra rng gi tin n bin, sau n thc hin qu trnh chuyn tip gi tin da vo cc thng tin khc nh Header tng mng v i vo vng ch. Trao i nhn l qu trnh ch yu ca MPLS

Hnh 1.1: M hnh chuyn mch nhn1.2.1.2. Hot ng ca MPLSMPLS s dng cc nhn chuyn tip gi tin, Nt u vo MPLS n nh mt nhn cho mt FEC c th. Nhn c di c nh c gn vo gi trc khi truyn i. Nhn c s dng nh l mt ch dn vo trong bng v ch ra chng tip theo v nhn mi. Nhn c c thay th bng nhn mi v gi c chuyn tip ti chng tip theo.Do s dng nhn, MPLS c mt s c im sau:

Chuyn tip c th thc hin bi chuyn mch, ch xem xt v thay th nhn, khng kim tra tiu lp mng.

Mt gi tin c n nh cho mt FEC khi n i vo mng. B nh tuyn ingress c th s dng bt c thng tin m n c v nhn thm ch thng tin khng c cha trong tiu lp mng. y l c s xy dng MPLS VPN.

Cc mng k thut lu lng cng bc gi i theo mt ng c th. ng ny c chn khi gi i vo mng hn l dng thut ton nh tuyn ng khi gi i trong mng. y l c s cho MPLS-TE. Mt CoS (Class of Service) ca gi c th xc nh bi nt MPLS ingress. MPLS cho php th t u tin hay CoS l y hay tng phn c suy ra t nhn. Trong trng hp , nhn trnh by s kt hp ca mt FEC v th t u tin hay CoS. y l c s ca MPLS QoS.MPLS c th xem l mt tp cc cng ngh hot ng vi nhau phn phi gi tin t ngun ti ch mt cch c hiu qu v c th iu khin c. N s dng cc LSP chuyn tip lp 2 m c thit lp bo hiu bi cc giao thc nh tuyn lp 3.1.2.2. So snh cc cng ngh ATM, IP, MPLSc tnhIPATMMPLS

Mng iu khin mng

iu khin chp nhnKhungUNICha c lp

nh tuynOSPF, IS-IS, BGP4PNNIOPSF-TE, IS-IS-TE, BGP4-TE

Tnh ngKhngXuyn sut, cng bcXuyn sut, cng bc

Bo hiuKhngPNNIRSVP-TE, CR-LDP

Tn kt niKhngKt ni oLSP

Nhn dng kt niKhngVPI, VCIID nhn

nh tuyn hinDanh mc chuyn tip ringTuyn hin

Mng d liu mng:n v truynGi kch thc thay iT boGi/T bo

Kim sotKhngC cho hp ng a lu lngKhng

nh duKhngT bo c m bo l tun th hay khngKhng

Phn b mHn chD tr theo lungCha c chun

Lp lch trnhHn chTheo cng, theo lung v lpCha c chun

im mnh v hn ch:im mnh mm do, nhiu loi giao thc d liu dch v, tch hp vi UNIX, a nh cung cp, thc thi trn nn chunKh nng d on trc v tin cy mng. hon chnh trong tiu chun v th nghim. Phn tch L2, L3. Hiu sut bng thng mng ti u, phn ti xuyn sutCung cp hiu qu, kh nng d kin trc v n nh, h tr SLA v dch v Diffserv. Hiu sut bng thng ti u, phn ti xuyn sut

Hn chH tr hn ch dch v Diffserv, hn ch kh nng d on trc, mng t ti u, to nghn mng do bn cht cng nghCn qun l thm mng iu khin, vic tch hp ATM trong cc router t nn dn n s lng ln cc cn k router cn phi qun lTiu chun ang pht trin, t kinh nghim thc t, t kh nng kim sot m bo thng lng v ng u.

1.3. Cng ngh MPLS

1.3.1. Cc khi nim c bn

Nhn (Lable)

Nhn l mt thc th c di ngn v c nh khng c cu trc bn trong. Nhn khng trc tip m ho thng tin ca mo u lp mng nh a ch mng. Nhn c gn vo mt gi tin c th s i din cho mt FEC (Forwarding Equivalence Classes: Nhm chuyn tip tng ng) m gi tin c n nh.Thng th mt gi tin c n nh mt FEC (hon ton hoc mt phn) da trn a ch ch lp mng ca n. Tuy nhin nhn khng phi l m ho ca a ch .

Dng ca nhn ph thuc vo phng thc truyn tin m gi tin c ng gi.

Kiu khung (Frame mode): Kiu khung l thut ng khi chuyn tip mt gi nhn gn trc tiu lp ba. Mt nhn c m ho vi 20 bit, ngha l c th c 2 m 20 gi tr khc nhau. Mt gi c nhiu nhn gi l chng nhn (Lable stack). mi chng trong mng ch c mt nhn bn ngoi c xem xt

LABLE EXPS TTL STACK

LABLE=20 bits

EXP (EXPERIMENTAL)=3 bits

S (BOTTOM OF STACK)=1 bit

TTL (TIME TO LIVE)=8 bits

Trong :

EXP: dnh cho thc nghim. Khi cc gi tin xp hng c th dng cc bt ny tng t nh cc bit IP u tin (IP Precedence)

S: l bt cui chng . Nhn cui chng bit ny c thit lp ln 1,cc nhn khc c gi tr bt ny l 0.

TTL: thi gian sng l bn sao ca IP TTL. Gi tr ca n c gim ti mi chng trnh lp nh IP.

Kiu t bo (Cell mode): Thut ng ny dng khi c mt mng gm cc ATM LSR dng trong mt phng iu khin trao i thng tin VPI/VCI thay v dng bo hiu ATM. Trong kiu t bo, nhn l trng VPI/VCI ca t bo. Sau khi trao i nhn trong mt phng iu khin, mt phng chuyn tip, router cng vo phn tch gi thnh cc t bo ATM, dng gi tr VCI/CPI tng ng trao i trong mt phng iu khin v truyn t bo i. Cc ATM LSR pha trong hot ng nh chuyn mch ATM-chng chuyn tip mt t bo da trn VPI/VCI vo v thng tin cng ra tng ng. Cui cng, router cng ra sp xp cc t bo thnh mt gi.

Kiu khung PPP hoc Ethernet, gi tr nhn dng giao thc P-ID (hoc Ethernet type) c chn vo mo u khung tng ng thng bo khung l MPLS n hng hay a hng.

Hnh 1.2: Lp lin kt d liu l ATM

Hnh 1.3: Lp lin kt d liu Frame-relay

Hnh 1.4 : Nhn trong Shim-gia lp 2 v lp 3 Ngn xp nhn (Lable stack):L mt tp hp th t cc nhn gn theo gi chuyn ti thng tin v nhiu FEC v v cc LSP tng ng m gi i qua. Ngn xp nhn cho php MPLS h tr nh tuyn phn cp (mt nhn cho EGP v mt nhn cho IGP) v t chc a LSP trong mt trung k LSP. iu ny to iu kin thun li cho ch hot ng ng hm. Bng chuyn tip chuyn mch nhn:

Cha thng tin v nhn vo, nhn ra, giao din vo, giao din ra. B nh tuyn chuyn mch nhn ( LSR-Lable Switching Router ): L thit b chuyn mch hay thit b nh tuyn s dng trong mng MPLS chuyn cc gi tin bng th tc phn phi nhn. C mt s lo LSR nh LSR, LSR-ATM. Lp chuyn tip tng ng ( FEC-Forward Equivalence Class ): FEC l mt nhm cc gi, nhm cc gi ny chia s cng yu cu trong s chuyn tip chng qua mng. Tt c cc gi trong mt nhm nh vy c cung cp cng cch chn ng ti ch. Khc vi chuyn tip IP truyn thng, trong MPLS vic gn mt gi c th vo mt FEC c th ch c thc hin mt ln khi cc gi vo trong mng. MPLS khng ra quyt nh chuyn tip vi mi datagram lp 3 m s dng khi nim FEC. FEC ph thuc vo mt s cc yu t, t nht l ph thuc vo a ch IP v c th l ph thuc c vo kiu lu lng trong datagram (thoi, d liu, fax).

C s thng tin nhn ( LIB-Lable Information Base ):

L bng kt ni trong LSR c cha gi tr nhn/ FEC c gn vo cng ra cng nh thng tin v ng gi d liu truyn tin xc nh phng thc mt gi tin c chuyn tip.

Tuyn chuyn mch nhn ( LSP-Lable Switching Path ):

L tuyn to ra t u vo n u ra ca mng MPLS dng chuyn tip gi ca mt FEC no s dng c ch hon i nhn. Cc tuyn chuyn mch nhn cha mt chui cc nhn ti tt c cc nt dc theo tuyn t ngun ti ch. LSP c thit lp trc khi truyn d liu hoc trong khi xc nh lung d liu no . Cc nhn c phn phi bng cc giao thc nh LDP, RSVP

Gi tin dn nhn:

Gi tin dn nhn l gi tin m nhn c m ha trong . Trong mt s trng hp, nhn nm trong mo u ca gi tin dnh ring cho mc ch dn nhn. Trong cc trng hp khc, nhn c th c t chung vo trong mo u lp mng v lp lin kt d liu min l y c th dng c cho mc ch dn nhn. Cng ngh m ho c s dng phi ph hp vi c thc th m ho v thc th gii m nhn.

n nh v phn phi nhn:

Trong mng MPLS, quyt nh kt hp mt nhn L c th vi mt FEC F c th l do LSR pha trc thc hin. LSR pha trc sau khi kt hp s thng bo vi LSR pha sau v s kt hp . Do vy, cc nhn c LSR pha trc n nh v cc kt hp nhn c phn phi theo hng t LSR pha trc ti LSR pha sau. C cu bo hiu Yu cu nhn: Mt LSR yu cu mt nhn t dng xung ln cn nn n c th lin kt n FEC xc nh. C cu ny c th dng truyn n cc LSR tip theo cho n LER li ra.

p ng nhn: p ng mt yu cu nhn, LSR lung xung s gi mt nhn n cc b khi ng lung ln s dng c cu nh x nhn.

Hnh 1.5: C cu bo hiu1.3.2. Yu cu cng ngh MPLS

Nhm lm vic MPLS a ra cc yu cu i vi MPLS nh sau: MPLS phi c kh nng lm vic vi hu ht cc cng ngh lin kt d liu.

MPLS phi thch ng vi cc giao thc lp mng v cc cng ngh IP lin quan.

MPLS cn hot ng c lp vi giao thc nh tuyn.

MPLS phi h tr mi kh nng chuyn tip ca nhn bt k.

MPLS phi h tr chc nng vn hnh qun l v bo dng.

MPLS cn xc nh v ngn chn chuyn tip vng.

MPLS phi hot ng tt trong mng phn cp.

MPLS phi c tnh k tha.

1.3.3. Thnh phn trong cng ngh MPLS

Thnh phn c bn ca MPLS l cc LSR.

LSR Label Swich Route: L thit b b nh tuyn hoc chuyn mch s dng trong mng MPLS chuyn cc gi tin bng th tc phn phi nhn. Cn c vo chc nng ca LSR c th phn thnh cc loi chnh sau:

Loi LSRChc nng thc hin

LSRChuyn tip gi c nhn

LSR binNhn gi IP, kim tra ti lp 3 v t vo ngn xp nhn trc khi gi gi vo mng LSR.(Ingress)

Nhn gi tin c nhn, loi b nhn, kim tra ti lp 3 v chuyn tip gi IP n nt tip theo.(Egress)

ATM-LSRS dng giao thc MPLS trong mng iu khin thit lp knh o ATM. Chuyn tip t bo n nt ATM-LSR tip theo.

ATM-LSR binNhn gi c nhn hoc khng nhn, phn vo cc t bo ATM v gi cc t bo n nt ATM-LSR tip theo.

Nhn cc t bo ATM t ATM-LSR cn k, ti to cc gi t t bo ATM v chuyn tip gi c nhn hoc khng nhn.

1.3.4. Cc c ch hot ng ca MPLS

MPLS c hai ch hot ng da trn hai mi trng mng li ph bin hin nay l FR v ATM. Ch hot ng khung MPLS (Frame-mode) : - Ch hot ng ny xut hin khi s dng MPLS trong mi trng cc thit b nh tuyn thun nht, nh tuyn cc gi in IP (im_im). Cc gi tin gn nhn c chuyn tip trn c s khung lp 2.- C ch hot ng ca mng MPLS trong ch hot ng ny c m t tronghnh.

Hnh 1.6 Mng MPLS trong hot ng ch khung

Cc hot ng trong mng s liu:Qu trnh chuyn tip mt gi IP qua mng MPLS. Th hin qua mt s bc:

LSR bin li vo nhn gi IP, phn loi gi vo nhm chuyn tip tng ng FEC v gn nhn cho vi ngn xp nhm tng ng FEC xc nh. Trong trng hp nh tuyn ch mt a ch ch, FEC tng ng s l mt mng con ch v vic phn loi gi s n gin l vic so snh bng nh tuyn lp 3 truyn thng. LSR li nhn gi tin c nhn v s dng bng nh tuyn chuyn tip nhn thay i nhn ni vng trong gi n vi nhn ngoi vng tng ng cng vi FEC (trong trng hp ny l mng con IP). Khi LSR bin li ra ca vng FEC ny nhn c gi c nhn, n lm nhim v b nhn v thc hin chuyn tip gi IP theo bng nh tuyn lp 3 truyn thng. Mo u nhn. V phi c chn trc s liu nh nhn trong ch hot ng khung. Nh vy nhn MPLS c chn vo gia mo u lp 2 v ni dung thng tin lp 3 ca khung lp 2 nh trong hinh 2.2 Do nhn MPLS c chn vo v tr nh vy nn b nh tuyn gi thng tin phi c phng tin g thng bo cho Router nhn rng gi ang c gi i khng phi l gi IP thun m l gi c nhn (gi MPLS).

Hnh 1.7 V tr ca nhn MPLS trong khung lp 2

Trong mi trng LAN, cc gi c nhn truyn ti gi lp 3 Unicast hay mulicast s dng gi tr 8847 H v 8848 H cho dng Ethernet. Cc gi tr ny s dng trc tip trn phng tin Ethernet. Cc gi MPLS truyn gia mt cp Router qua knh o ATM Forum c bc vi mo u SNAP s dng gi tr cho dng Ethernet nh trong mi trng LAN.- Chuyn mch nhn trong ch khung:

Chng ta xem xt qu trnh chuyn i nhn trong mng MPLS sau khi nhn uc mt gi IP Sau khi nhn khung PPP lp 2 t Router bin s 1, LSR li 1 lp tc nhn dng gi tin nhn dng gi tin nhn c l gi c nhn da trn gi tr trng giao thu PPP v thc hin kim tra nhn trong c s d liu chuyn tip nhn LFIB Kt qu cho thy nhn vo l 30 c thay th bng nhn ra 28 tng ng vi vic gi tin s chuyn tip n LSR li 2.

Ti y nhn c kim tra, nhn s 28 c thay th bng nhn s 37 v nhn ra c xc nh gi tin chuyn n LSR bin s. Ti LSR bin s 3, nhn 37 b loi b v vic kim tra a ch lp 3 c thc hin, gi tin c chuyn n Router ngoi mng MPLS.

Cc gi chuyn mch trn c p dng vi cc gi tin c 1 nhn hay c nhiu nhn ( trong trng hp VPN thng thng mt nhn c gn c nh cho VPN Server.)

Qu trnh lin kt nhn v lan truyn nhn.

Khi xut hin mt LSR mi trong mng MPLS hay bt u khi to mng MPLS, cc thnh vin LSR trong mng MPLS phi c lin lc vi nhau qua qu trnh khai bo thng tin qua bn tin Hello. Sau khi bn c gi mt phn giao dch gia 2 LSR c thc hin.Th tc giao dch l giao thc LDP.

Ngay sau khi LIB (c s d liu nhn) c to ra trong LSR nhn c gn cho mi FEC m LSR nhn bit c. i vi trng hp chng ta ang xem xt nh tuyn da trn ch Unicast, FEC tng ng vi Frefix trong bng nh tuyn IP v bng nh tuyn chuyn i khc trong LIB. Bng chuyn i ny c cp nht lin tc khi xut hin nhng ni dung mi, nhn mi c gn cho tuyn mi.

Do LSR dn nhn cho mi IP Prefix trong bng nh tuyn v nhn l phng tin c LSR khc s dng khi gi tin c nhn n LSR nn phng php v phn phi nhn ny c gi l gn nhn c lp vi qu trnh phn phi ngc khng yu cu.

Vic lin kt cc nhn c qung b ngay n tt c cc Router thng qua phin LDP.

Ch hot ng t bo MPLS (Cell-mode): Khi xem xt trin khai MPLS qua ATM cn phi gii quyt mt s tr ngi sau:

Hin tng khng tn ti mt c ch no cho vic trao i trc tip cc gi tin IP gia 2 nt MPLS cn k qua giao din ATM phi c thc hin qua knh o ATM.

Cc tng i ATM khng th thc hin vic kim tra nhn hay a ch lp 3. Kh nng duy nht ca tng i ATM l chuyn i t VC u vo sang VC u ra ca giao din ra.

Nh vy cn thit phi xy dng mt s c ch m bo vic thc thi MPLS qua ATM nh sau:

Cc gi IP trong mng iu khin khng th trao i trc tip qua giao din ATM. mt knh o VC phi c thit lp gia 2 nt MPLS k cn trao i gi thng tin iu khin .

Nhn trn cng trong ngn xp phi c s dng cho cc gi tr VPI/VCI.

Cc th tc gn v phn phi nhn phi m bo cho cc tng i ATM khng phi kim tra a ch lp 3.

- Kt ni trong mng iu khin thng qua giao din LC-ATM.Cu trc MPLS i hi lin kt thun IP gia cc mng iu khin ca cc LSR ln cn trao i lin kt nhn cng nh cc gi iu khin khc .Nh vy ch hot ng t bo c hot ng theo cc bc sau: Bc 1: Gi yu cu cho gi tr nhn X n nt cn k.

Bc 2: ATM-LSR li 1 gi yu cu gi tr nhn X n ATM-LSR li 2.

Bc 3: ATM-LSR li 2 gi yu cu gi tr nhn X n ATM-LSR bin 3.

Bc 4: LSR bin 3 gn gi tr VPI/VCI v gi tr li ATM-LSR li 2.

Bc5: LSR li 2 gn gi trin VPI/VCI ni vng, chuyn i VPI/VCI vo sang VPI/VCI ra v gi gi tr VPI/VCI mi n ATM-LSR li 1.

Bc 6: Gi tr VPI/VCI ni vng c gn bi ATM-LSR li 1 gi n LSR bin 1 tr li yu cu

Hnh 1.8 : Mng MPLS trong ch hot ng t bo

.

Hnh 1.9 : Trao i thng tin gia cc LSR cn k

Chuyn tip cc gi c nhn qua min ATM-LSR

Vic chuyn tip cc gi c nhn qua min ATM-LSR c thc hin trc tip qua cc bc sau:

ATM-LSR bin li vo nhn gi c nhn hoc khng c nhn, thc hin vic kim tra c s d liu chuyn tip FIB hay c s d liu chuyn tip nhn LFIB v tm ra gi tr VPI/VCI u ra s dng nh nhn li ra. Cc gi c nhn c phn chia thnh cc t bo ATMv gi n ATM-LSR tip theo. Gi tr VPI/VCI c gn vo tiu tng t bo.

Cc nt ATM-LSR chuyn mch t bo theo gi tr VPI/VCI trong tiu ca t bo theo c ch chuyn mch ATM truyn thng. C ch phn b v phn phi nhn phi m bo vic chuyn i gi tr VPI/VCI ni vng v ngoi vng l chnh xc.

ATM-LSR bin li ra (khi min ATM-LSR) ti to li cc gi c nhn t cc t bo, thc hin vic kim tra nhn v chuyn tip t bo n LSR tip theo. Vic kim tra nhn da trn gi tr VPI/VCI ca t bo n m khng da vo nhn trn nh ca ngn xp trong tiu nhn MPLS do ATM-LSR gia cc bin ca min ATM-LSR ch thay i nhn bn trong cc t bo ATM. Lu rng nhn nh ca ngn xp c lp gi tr bng 0 bi ATM-LSR bin li vo trc khi gi c nhn c phn chia thnh cc t bo.1.3.5. Giao thc c bn ca MPLSQu trnh hot ng ca mng MPLS s dng cc giao thc sau:

Giao thc iu khin gn nhn (c lp v theo yu cu)

Giao thc pht hin v chng vng lp

Giao thc phn phi nhn LDP

Giao thc ginh trc ti nguyn RSVP

Giao thc CR-LDP

Giao thc MPLS-BGP

1.3.6 TNG KT Chng ta tm hiu nhng thnh phn chnh trong k thut chuyn mch a giao thc MPLS. Chc nng c bn nht ca MPSL l phc v cho vic chuyn gi d liu bng thut ton chuyn mch trn ng dn c xc nh bng k thut nh tuyn da vo a ch ch ( destination_based routing). Giao thc phn phi nhn LDP ( Label Switching Path), trn ng nh tuyn ny. Giao thc LDP hot ng trn kt ni TCP v cung cp nhiu hnh thc phn b nhn khc nhau nh : xui dng ( downstream) hay xui dng theo yu cu ( downstream on demand), iu khin LSP c lp( Independent) hay theo th t ( ordered LSP control, t do (liberal) hay duy tr m thoi (converative label retention). Ngoi ra vn c nhng giao thc khc phc v cho vic xy dng LSP nh : RVSP, BGP.CHNG II: GII THIU CNG NGH GMPLS2.1. Gii thiu chungCng ngh chuyn mch nhn a giao thc tng qut GMPLS (Generalized Multiprotocol Labed Switching) l bc pht trin theo ca cng ngh chuyn mch nhn a giao thc MPLS. GMPLS thc cht l s m rng chc nng iu khin ca mng MPLS, n cho php kin to mt phng iu khin qun l thng nht khng ch lp mng m cn thc hin i vi cc lp ng dng, truyn dn v lp vt l. Vic kin to mt mt phng iu khin thng nht i vi cc lp mng ha hn kh nng to ra mt mng n gin v iu hnh v qun l, cho php cung cp cc kt ni t u cui ti u, qun l ti nguyn mng mt cch hon ton t ng v cung cp cc mc cht lng dch v (QoS) khc nhau cc ng dng trn mng.

Cng ngh GMPLS cho php cc nt mng t ng cung cp cc kt ni theo yu cu do vy gi thnh chi ph cung cp kt ni cng nh gi thnh qun l bo dng gim i rt nhiu, thi gian cung ng kt ni cung cp dch v gim i rt nhiu so vi phng php truyn thng (tnh theo gi hoc pht so vi tun hoc thng ca phng thc nhn cng truyn thng). Cc chc nng ca GMPLS c m t trong bng 2.1:

Bng 2.1: Chc nng thc hin trong GMPLSVng chuyn mchKiu lu lngLc chuyn tipThit b v dK hiu

Gi, t boIP, ATMNhn, kt ni knh oB nh tuyn IP, ATM switchingChuyn mch gi (PSC)

Thi gianTDM / SONETKhe thi gianH thng u ni cho(DSC), ADMChuyn mch TDM

Bc sngTrong sutLambdaDWDMChuyn mch Lambda(LSC)

Vt lTransparentFiber, lineOXCChuyn mch si quang(FSC)

2.2. B giao thc GMPLS

S pht trin MPLS thnh GMPLS m rng giao thc bo hiu (RSVP-TE, CR-LDP) v giao thc nh tuyn (OSPF-TE, IS-IS-TE). Cc m rng ny dng cho cc c tnh mng quang v TDM/SONET. Ngoi ra trong GMPLS thm vo giao thc qun l lin kt LMP (Link Management Protocol). Giao thc qun l lin kt l mt giao thc mi qun l v bo dng mt phng iu khin v mt phng d liu gia hai node ln cn nhau. LMP l giao thc da trn IP bao gm cc m rng i vi RSVP-TE v CR-LDP. Bng 2.2 tm tt cc giao thc v cc m rng ca GMPLS .

Bng 2.2: Cc giao thc v cc m rng ca GMPLSnh tuynOSPF-TE, IS-IS-TEGiao thc nh tuyn dng cho vic khm ph mt cch t ng v topo mng, thng bo cc ti nguyn kh dng. Mt s tng cng chnh gm:

_ Cho bit loi bo v tuyn (1+1, 1:1, khng bo v, lu lng ph thm).

_ Nhn v thng bo cc lin kt khng c a ch IP-nhn dng lin kt.

_ Nhn dng giao din vo v ra.

_ Khm ph tuyn khc nhau cho d phng.

Bo hiuRSVP-TE, CR-LDPGiao thc bo hiu dng cho qu trnh thit lp cc LSP mang lu lng. Cc tng cng chnh:

_ Trao i nhn, bao gm c cc mng khng phi chuyn mch gi.

_ Thit lp cc LSP 2 hng.

_ Bo hiu thit lp ng d phng.

_ Thc y vic gn nhn thng qua cc nhn c xut.

_ H tr chuyn mch bng tn-tp cc bc sng gn nhau c chuyn mch vi nhau.

Qun l lin ktLMP_ Qun l knh iu khin: c thit lp bi cc thng s lin kt (v d nh tn s gi bn tin keep-alive) v m bo s hot ng tt cho c lin kt.

_ Kim tra vic kt ni lin kt: m bo kt ni vt l ca lin kt gia cc node ln cn, s dng mt ping-nh bn tin kim tra.

_ Lin h cc c tnh lin kt: Xc nh cc c tnh lin kt ca cc node ln cn.

_ C lp li: C lp cc li n hoc li kp trong min quang

2.3. Hot ng ca GMPLS.

2.3.1. nh tuyn.

Hot ng v vai tr ca thut ton nh tuyn theo ng ngn nht c rng buc (CSPF-Constrain Short Path First): Khi c mt yu cu dch v khi to t mt phn mm qun l nh SNMP n node u vo. Node ny tm kim trong c s d liu TE tm ra ng tt nht gia cc im cui dch v. Tt nht y c hiu l ng c s lin kt hoc tr mng nh nht trong khi vn tho mn c cc rng buc v chnh sch yu cu ca ngi s dng. Cc rng buc l vn c quan tm nht ca mt phng iu khin thng minh.

Nhng rng buc c bn bao gm:

-Trnh cc lin kt v node c th: iu ny c s dng thng xuyn nhn c nhng ng c lp v li. Node v lin kt c cng mc ri ro c tp hp thnh nhm. 2.3.2. Bo hiu dch v

Vic cu hnh mi thnh phn c mt trn ng vi mi tham s cn thit phi c thc hin bt u dch v. Trong mng GMPLS s dng cc giao thc bo hiu RSVP-TE v CR-LDP, l m rng ca cc giao RSVP kt hp vi k thut lu lng.

Vai tr ca RSVP-TE hay CR-LDP trong bo hiu dch v: Mt khi la chn c ng, cc giao thc bo hiu nh RSVP-TE s c s dng thit lp mi thnh phn mng trn ng . 2.3.3. X l li mt phng iu khin

Hai loi chnh ca li c th tc ng vo mt phng iu khin. Loi th nht c gi l li knh iu khin, li ny lin quan ti vic mt thng tin iu khin gia hai node ln cn.

Hnh 2.1: Mt s li xy ra trong GMPLS

Loi th hai c gi l li node, li ny lin quan n cc node mt trng thi iu khin (sau khi khi ng li chng hn) nhng khng mt trng thi chuyn tip d liu ca n. Trong cc mng vn chuyn, nhng loi li mt phng iu khin nh vy khng c gy ra nh hng n cc kt ni ang tn ti. Cho nn phi c c ch pht hin cuc lin lc iu khin b tht bi v th tc khi phc phi m bo s kt ni ti hai u cui ca knh iu khin.

2.4. K thut nh tuyn trong GMPLS

2.4.1. nh tuyn trong MPLS

Cng nh trong mng IP truyn thng, nh tuyn trong mng MPLS thc hin hai chc nng sau:

_ Qung b thng tin v topo mng: Qung b cc thng tin v topo qua mng to thnh mt tp cc ti nguyn mc mng khng i gia cc LSR. Tuy nhin, tp khng i ny khng c ngha l ging nhau. V mng c th c chia thnh cc cp theo kha cnh kinh doanh, k thut hay a l, cc LSR cn phi c trang b thng tin thc hin vic chn ng ti cc mc khc nhau. Vn mu cht ca vic truyn thng tin qung b topo mng l tr li c nhng cu hi ci g, cho ai , v bng cch no . Ngha l thng tin no cn c phn phi n ai v bng cch no truyn thng tin ny i.

Qung b thng tin v topo mng

Mc ch ca vic qung b thng tin v topo mng l thng bo cc thng tin cn thit, y mt cch hiu qu cho cc LSR chng c kh nng chn mt ng i ti u cho gi tin. Mi quan tm chnh i vi qung b thng tin topo l kh nng nng cp.

Chn ng

Chn ng c th thc hin theo phng thc online hay offline. Vic chn phng n no tu thuc vo phc tp tnh ton, thng tin topo c th ca cc tnh hung c th. C hai phng thc chn ng ny u c th thc hin. Chng hn nh khai thc c th s dng thut ton online x l tp cc quyt nh chn ng v thut ton offline x l lu lng phc tp.

Ci tin nh tuyn trong GMPLS

Trong mng GMPLS giao thc nh tuyn phi c ci tin ph hp vi cu trc ca n, tc l n phi h tr cho mng quang iu khin, mng ghp knh theo thi gian. Mt khc vi tc tng ca lu lng hin nay i hi s ng cp cn cung cp u ni gia cc b nh tuyn rt ln. Do xut hin nhng vn sau:

-S lng lin kt trong mng GMPLS c yu cu c th ln hn trong mng MPLS.

-Pht hin li nhanh v chuyn knh c li ti knh thay th. hiu r hn v cc ci tin nh tuyn, ta xt qua cc giao thc v trng thi nh tuyn nh IS-IS v OSPF. Trong ta coi mng l mt lu v cc node l cc thnh phn mng v bin mng l nhng ng ni (cp). Nhng bin trong lu c cc thuc tnh gn vi n nh: a ch IP, chi ph v bng thng dnh sn.

2.4.2. K thut nh tuyn h tr cht lng dch v MPLS/GMPLS

a) nh tuyn m bo QoS trong MPLS

nh tuyn QoS xc nh tuyn da trn ti nguyn mng hin c v yu cu ca lung lu lng. Kt qu l cht lng ca ng dng c m bo v ci tin so vi nh tuyn n lc ti a truyn thng. N c cc u im sau:

Nu ti lu lng vt qu gii hn ca tuyn ng ang c th nh tuyn m bo QoS a ra nhiu tuyn khc truyn lu lng d .

_ Nu xy ra li mng hoc li nt th nh tuyn m bo QoS s la chn mt tuyn ng i thay th nhanh chng khi phc li vic truyn d liu m khng lm gim nhiu QoS.

_ Cc loi lu lng khc nhau c yu cu QoS khc nhau, cc t hp lu lng c ngun v ch ging nhau c th i cc tuyn ng khc nhau.

b) Mt s thut ton nh tuyn QoS trong MPLS

Cc gii php nh tuyn m bo QoS trong MPLS c ci thin t thut ton tm ng ngn nht v b sung mt s iu kin rng buc ca mng. Mt s thut ton h tr nh tuyn m bo QoS trong mng MPLS c trnh by di y.

Thut ton bc nhy ti thiu MHA (min Hop Algorithm): Thut ton bc nhy ti thiu l thut ton n gin nht nhm tm ra mt ng dn vi s bc nhy ti thiu t ngun ti ch, mc d thut ton ny c kh nng tm c ng dn p ng c yu cu bng thng v c u im l tnh ton nhanh, nhng MHA gy ra hin tng nghn c chai ti lin kt ti ln trong mng.

Thut ton tm ng ngn nht v rng nht WSPA (Widest Sortest Path Algorithm): Thut ton tm ng ngn nht v rng nht (WSPA) l mt thut ton ci tin t thut ton bc nhy ti thiu nhm cn bng ti lu lng mng.

Thut ton nh tuyn nhiu ti thiu MIRA (Minimum Inteference Routing Algorithm): Mc tiu ca thut ton ny l cung cp ng dn c nhiu t nht vi cc yu cu kt ni ng dn chuyn mch nhn LSP trong tng lai gia cc cp ngun ch khc. Thut ton ny gi thit c mt s nhn nh v tim nng ca cc cp ngun- ch.

2.4.3. nh tuyn gn bc sng trong GMPLS

Do GMPLS gn trc tip ti iu khin lung quang nn bi ton nh tuyn trong GMPLS phi tm c cc bc sng c la chn bng cch ti thiu tc nghn cho chui cc kt ni. Di y l mt s thut ton in hnh.

Thut ton gn bc sng theo th t bc sng. Mt v d v thut ton gn bc sng n gin nhng hiu qu l gn bc sng theo th t bc sng. Trong thut ton ny, cc bc sng c nh ch s v lung quang s c gng la chn bc sng vi ch s thp nht trc khi la chn bc sng vi mt ch s cao hn.

Thut ton gn bc sng ngu nhin. Phong php khc la chn cc bc sng khc nhau l la chn n gin mt trong cc bc sng ngu nhin. Ni chung, thut ton gn bc sng theo th t bc sng s lm tt hn gn bc sng ngu nhin khi thng tin y v trng thi mng c th s dng. Thut ton gn bc sng da trn bc sng s dng nhiu nht v t nht. Thut ton gn bc sng n gin khc bao gm thut ton gn bc sng da trn bc sng s dng nhiu nht v t nht. t trc song song. Bi ton da trn nh tuyn trng thi lin kt cho rng mi nt duy tr thng tin tng th v cu hnh mng v trng tha hin ti ca mng bao gm thng tin v cc bc sng ang c s dng trn mi tuyn lin kt. Da trn thng tin tng th ny nt c th tnh ton tuyn ti u ti ch vi bc sng nht nh. t trc theo chng. Khc vi t trc song song l t trc theo chng trong bn tin iu khin c gi dc theo tuyn la chn tng chng k tip nhau. mi nt trung gian, bn tin iu khin c x l trc khi chuyn tip ti nt tip theo. Khi bn tin iu khin tin ti ch, n c x l v gi li nt ngun.

2.5. Kt lun chng II

Trong chng II gii thiu v cng ngh chuyn mch GPMLS. N c ng dng trong mng iu khin, thc hin qun l kt ni cho mng s liu gm c chuyn mch gi, chuyn mch knh (nh TDM, chuyn mch bc sng v chuyn mch quang). Trong chng ny cng trnh by y b giao thc GMPLS, hot ng, k thut nh tuyn ca cng ngh GMPLS. Qua ta c th hiu c nhng vn lin quan ti gii php v cng ngh trong GMPLS cng nh nm c nhng vn c bn ca cng ngh GMPLS.

CHNG III:NG DNG CNG NGH MPLS/GMPLS3.1 NG DNG CA CNG NGH MPLS

3.1.1 MNG RINNG O VPN (Virtual Private Network VPN ).Mng ring o VPN (Virtual Private Network) l mt trong nhng ng dng rt quan trng trong mng MPLS. Cc cng ty, doanh nghip c bit cc cng ty a quc gia c nhu cu rt ln v loi hnh dch v ny. Vi VPN h hon ton c th s dng cc dch v vin thng, truyn s liu ni b vi chi ph thp, an ninh bo m. Nh c c ch bo mt v cung cp lp dch v (QoS) theo yu cu m MPLS l mt cng ngh rt ph hp cho mng ring o VPN. phn ny chng ta s tm hiu v m hnh mng ring o trn mng MPLS. y l mt ng dng rt quan trng p ng cc yu cu ca cc mng ring s dng h tng c s thng tin quc gia vi nhng yu cu khc nhau v an ton, bo mt v cht lng dch v. An ninh mng khng ch quan trng i vi cc nh cung cp dch v ISP m cn c ngha quyt nh i vi cc c quan chnh ph v cc doanh nghip. Cc gii php cho h thng WAN nh s dng ng dy thu ring, Frame-relay khng c s mm do linh hot v mt kt ni, m rng mng cng nh an ton thng tin, hn na chi ph li cao.

3.1.1.1 S pht trin ca VPN.

Ban u cc mng my tnh c trin khai vi hai cng ngh chnh: leased-lines cho cc kt ni lu di v dial-up lines cho cc kt ni khng lin tc, ch khi c yu cu.

Hnh 3. 1: Mng my tnh in hnh cch y 16 nm

Ban u mng my tnh c trin khai cho khch hng vi tnh bo mt kh tt, nhng gi c li kh cao bi hai l do sau: Lu lng trao i gia hai vng trong mng thay i theo tng thi im trong ngy, tng ngy trong thng, thm ch l theo ma (v d, lu lng trong t c s kin quan trng tng ln ng k).

Ngi s dng u cui lun lun yu cu c p ng nhanh, kt qu l yu cu bng thng cao gia cc site, nhng bng thng thu ch c s dng trong mt khong thi gian khi cc users trng thi active.

Hai l do trn thc y cc nh cung cp dch v pht trin v trin khai mt cng ngh cung cp cho khch hng vi cht lng dch v tng ng vi ng leased lines.

Hnh 3. 2: Mng Frame-relay c trng

3.1.1.2 Phn loi VPN

C 3 loi mng ring o, l: Intranet VPN: VPN kt ni hai mng vi nhau (site-to-site). c s dng kt ni cc vn phng, chi nhnh trong mt cng ty. Extranet VPN: c s dng khi c nhu cu trao i thng tin gia mng ca cng ty vi mng ca cc i tc bn ngoi.

Hnh 3. 3: M hnh mng Extranet Remote acces VPN (VPN truy cp t xa): c dng cho nhng ngi lm vic di ng, cn phi truy cp an ton vi mng ti mng ring ca cng ty t bt k v tr a l no thng qua mt mi trng chia s (nh mng in thoi cng cng). Mt s vn phng nh cng c th s dng kiu truy cp ny ni vi mng ring ca cng ty mnh. Thc t, ngi dng t xa s kt ni ti nh cung cp dch v Internet (ISP) v ISP s thit lp kt ni ti mng ring ca cng ty. Sau khi to c kt ni gia hai my tnh ca ngi dng xa vi mng ring ca cng ty, mt ng hm s c thit lp gia hai u cui v d liu c trao i qua ng hm .

3.1.1.3 Chc nng ca VPN

VPN c cc chc nng c bn sau: S tin cy: Ngi gi c th m ha cc gi d liu trc khi chng c truyn qua mng. Bng cch ny th ngi khc khng th truy cp thng tin m khng c s cho php. Nu c ly c th cng khng c c Tnh ton vn: Ngi nhn c th kim tra rng d liu c truyn qua mng Internet m khng c s thay i no Xc thc ngun gc: Ngi nhn c th xc thc ngun gc ca gi d liu, m bo v xc thc ngun thng tin.

3.1.2 Truyn Ti( NGN)

3.1.2.1 M u

Xc nh c xu hng tt yu ca th trng vin thng th gii, cng nh nhu cu thng tin, vin thng trong nc, hi ng qun tr Tng cng ty bu chnh vin thng Vit Nam a ra quyt nh s 393 Q/VT/HQT ngy 16/11 nm 2001 v vic ph duyt nh hng t chc mng vin thng n nm 2010. Trong xc nh vic xy dng mng th h k tip NGN cho Tng cng ty BCVT.

Cu trc mng vin thng th h k tip (NGN) phi m bo c cc yu cu sau:

Cung cp cc dch v thoi v truyn s liu bng rng bao gm: thoi, fax, di ng, ATM, IP, IP-VPN, FR, X25, xDSL, IN,trn c s h tng thng tin thng nht.

Mng c cu trc n gin, gim ti thiu cp chuyn mch nhm nng cao cht lng dch v v h thp gi thnh dch v.

Cu trc phi c tnh m, c linh hot v tnh sn sng cung cp dch v cao.

Mng tun th theo cc tiu chun quc t c Tng cc Bu in la chn p dng cho mng vin thng Vit Nam m bo tnh tng thch kt ni vi cc mng khc, cc nh khai thc khc.

Cu trc phi m bo tnh an ton cao nhm duy tr dch v v p ng nhu cu phc v an ninh quc phng.

Bo ton vn u t ca VNPT i vi mng hin ti.

Cu trc mng c t chc khng ph thuc vo a gii hnh chnh.

H thng qun l mng, qun l dch v c tp trung cao, bo m vic cung cp dch v n tn cc thu bao thuc cc vng hnh chnh khc nhau. 3.1.2.2 Cu trc phn lp chc nng NGN

Cc hng cung cp thit b v cc nh khai thc trn th gii a ra mt nguyn tc t chc mi cho mng vin thng trong giai on ti gi l mng th h k tip NGN. Cu trc mng th h k tip c phn chia lm 4 lp, l:

Lp ng dng dch v

Lp iu khin kt ni

Lp truyn ti

Lp truy nhp

Lp qun l c coi nh mt mt theo phng thng ng qun l cc lp chc nng trn.

Vic t chc phn lp chc nng ca mng ny m bo cho kh nng trin khai cng ngh v thit b mt cch ti u ti nhiu a im, trong tng lp v trong tng thi im hp l.

3.1.2.3 Nguyn tc t chc mng

Nguyn tc t chc mng da trn s lng thu bao theo vng a l v nhu cu pht trin dch v, khng t chc theo a bn hnh chnh m t chc theo phn vng lu lng.

Phn cp mng. Mng mc tiu ca VNPT s c phn thnh 2 cp, l:

Cp ng trc: gm ton b cc node chuyn mch, nh tuyn, truyn dn ng trc trn mng ca VTN v VTI c t chc thnh hai mt bng kt ni cho m bo an ton cao nht. Khng c t chc cp chuyn mch quc t, cc kt ni quc t s do cc node ng trc m nhn thng qua cc MG. Cc knh kt ni s l cc knh trung k tc cao (ti thiu l STM-1).

Cp truy nhp: gm ton b cc nt truy nhp ca cc khu vc trn ton quc. Khng phn chia nt truy nhp theo a bn hnh chnh. Cc nt truy nhp ca cc vng lu lng ch c kt ni n nt ng trc ca vng m khng c kt ni n vng khc. Phn vng lu lng. Cn c vo kt qu d bo nhu cu dch v v lu lng n nm 2010, mng mc tiu 2010 ca VNPT c phn thnh 5 vng lu lng. Phn vng iu khin. Tng ng vi phn vng lu lng s c 5 vng iu khin .3.1.2.4 T chc cc lp chc nng trong NGN

Lp ng dng v dch v c t chc thnh mt cp duy nht cho ton mng nhm m bo cung cp dch v n tn nh thu bao mt cch thng nht v ng b. S lng node ng dng v dch v ph thuc vo dch v cng nh s lng v loi hnh dch v c t chc phn tn theo dch v m bo tnh an ton ca h thng.

T chc lp iu khin

Lp iu khin c t chc thnh 1 cp thay v 4 cp nh hin nay nhm gim ti a cp mng v tn dng nng lc x l cuc gi rt ln ca thit b iu khin thit b th h mi, gim chi ph u t trn mng.

Lp iu khin c chc nng iu khin lp truyn ti v lp truy nhp mng NGN bao gm nhiu mun nh m un iu khin kt ni ATM, MPLS, iu khin nh tuyn IP, iu khin kt ni thoi, bo hiu s 7,

Cc nt iu khin c t chc thnh cp v kt ni trc tip vi 1 cp nt chuyn mch a dch v ng trc.

T chc lp truyn ti

Lp truyn ti phi c kh nng truyn ti cc loi lu lng nh ATM, IP, c t chc thnh hai cp: ng trc quc gia v vng thay v 4 cp nh hin nay.

Cp ng trc quc gia: gm ton b cc nt chuyn mch a dch v v cc tuyn truyn dn c t chc thnh 2 mt A&B kt ni cho gia cc nt ng trc vi tc ti thiu 2,5Gbit/s.

Cp vng: Gm ton b cc nt chuyn mch a dch v, cc b tp trung lu lng ni vng m bo chuyn mch cuc gi ni vng sang cc vng khc. Cc nt chuyn mch ny c t ti trung tm cc vng v kt ni trc tip vi nhau bng Ring qua cc cng quang ca nt chuyn mch a dch v.

T chc lp truy nhp

Lp truy nhp gm ton b cc nt truy nhp c t chc khng ph thuc theo a gii hnh chnh. Cc nt truy nhp ca cc vng lu lng ch c kt ni n chuyn mch ng trc ca vng tng ng qua nt chuyn mch vng

Cc PoP c kt ni vo mng NGN theo BRAS ti cc nt chuyn mch a dch v ni vng thng qua giao tip mc LAN vi tc ty thuc quy m ca PoP.

Cu trc phn cp mng v kt ni vi mng hin ti theo quy nh hng pht trin mng vin thng ca VNPT n nm 2010 c th hin nh hnh 3.1.

3.1.3 Truyn ti MAN - E

3.1.3.1 Cu trc mng E-MAN

Kin trc mng Metro da trn cng ngh Ethernet in hnh c th m t nh hnh 1-1. Phn mng truy nhp Metro tp hp lu lng t cc khu vc (c quan, to nh, ...) trong khu vc ca mng Metro. M hnh in hnh thng c xy dng xung quanh cc vng Ring quang vi mi vng Ring truy nhp Metro gm t 5 n 10 node.

Hnh 3.5 Cu trc mng MAN E in hnhNhng vng Ring ny mang lu lng t cc khch hng khc nhau n cc im POP m cc im ny c kt ni vi nhau bng mng li Metro. Mt mng li Metro in hnh s bao ph c nhiu thnh ph hoc mt khu vc tp trung nhiu doanh nghip.

3.1.3.2 Cc c tnh ca E-MAN

Khch hng c kt ni n E-MAN s dng cc giao din thch hp vi Ethernet thay v phi qua nhiu giai on bin i t lu lng ATM, SONET/SDH v ngc li. Bng cch ny khng ch loi b c s phc tp m cn lm cho qu trnh cung cp n gin i rt nhiu. M hnh Metro hnh thnh t qa trnh cung cp cc ng bng thng gia cc node v khch hng u cui cung cp cc mng LAN o (VLAN) v cc mng ring o (VPN) da trn mc tho thun dch v SLA.

Bng vic m rng mng LAN vo mng MAN s dng kt ni c bng tn ln hn, s khng cn s khc bit gia cc server ca mng vi cc router c t ti thit b ca khch hng v ti cc im POP ca nh cung cp mng na. Mt cng ty khc cung cp cc dch v ngun cho cc doanh nghip ny by gi c th thc hin t mt v tr trung tm cng vi im POP. ng thi cng khng cn phi duy tr cc router, cc server v cc firewall ti mi v tr khch hng. Kt qu l cc m hnh da trn thnh vin th ba ny gi c tnh kinh t hn rt nhiu. Khng nhng cc thit b mng c chia s gia nhiu khch hng vi nhau m cng khng cn phi duy tr i bo dng thng xuyn ti pha khch hng na.

3.2 NG DNG CA GMPLS 3.2.1 ng dng trong mng quangGMPLS c pht trin h tr cc hot ng MPLS trong mng quang v c th dng c nhng cng ngh khc nh phn thi gian (SONET, ADM), bc sng, chuyn mch khng gian ( cng vo hay si quang vo n cng ra hay si quang ra ).MPLS cho rng cc giao thc chuyn tip ca LRS ch c kh nng x l v nh tuyn cho cc tn hiu c ranh gii, khung, t bo (tc l cc thit b OEO). Ngc li, GMPLS cho rng cc LSR l cc thit b O/O/O khng th nhn bit c ranh gii ca cc gi hay t bo. Do , quyt nh chuyn tip da vo khe thi gian, bc sng hay cc cng vt l. Cc thng ip MPLS c dng trong mng quang mang cc thng tin c gi n LSR quang bng nhiu giao thc khc nhau (nh RSVP, LSP)

ngh nhn cho bc sng

GMPLS c th c dng cu hnh cho phn cng PXC. Mt phng php l nhn ngh c dng trong mt bc sng hay mt tp cc bc sng. N nh ngha cch dng mt tp cc nhn hn ch vic chn cc nhn thc hin gia cc nt GMPLS k cn. Cc tp nhn hu dng khi mt nt quang b hn ch bi mt s cc bc sng no , do khng phi nt quang no cng c kh nng v mt s nt quang c kh nng OEO trong khi mt s nt khc li c kh nng OOO.

Cc con ng chuyn mch nhn hai chiu trong mng quang

GMPLS nh ngha con ng chuyn mch nhn song hng c cng yu cu v k thut lu lng cho mi hng. thit lp mt con ng chuyn mch nhn LSP bng RSVP TE hay CR LDP, hai LSP n hng c thit lp mt cch c lp. Do iu bt li u tin l rt tn thi gian, th hai l phi trao i nhiu thng ip hn, th ba l cc loi LSP c lp nhau c th dn n cc tuyn khc nhau cho hai LSP.

LSP k cn chuyn tip FA LSP

FA LSP ( Forwawding Adjacency LSP) l mt LSP da trn GMPLS mang cc LSP khc. Mt FA LSP c thit lp hai nt GMPLS c xem nh mt lin kt o c cc c tnh TE ring, v c qung b cho OSPF/IS-IS nh l mt lin kt vt l bnh thng. FA LSP tham gia vo c s d liu trang thi lin kt v c dng trong vic tnh ton con ng v mang cc LSP khc. N gip gim kch thc c s d liu v thi gian tm kim trong bng ny. FA LSP c th c nh s hoc khng nh s v c th c gp vi cac lin kt khc.LSP phn tng

Khi mt lung u cui u cui c thit lp cho ng dng cn dng lng 10 M trong cc lin kt vt l gia hai mng l 100M nn s lng ph v khng hiu qu nu ta dng lin kt ny cho cc ng dng. S tt hn nu ta kt hp cc lung tc cao hn. N to thnh kin trc LSP phn tng.

Trong mt kin trc phn tng t nhin, mt nhm cc PSC LSP c lng trong cc TDM LSP v sau c lng trong mt LSC trong nhm cc LSC trong mt FSC.

Tnh tin cy

Mt c tnh quan trng ca tp hp cc giao thc GMPLS l kh nng qun l li mt cch t ng. Li trong loi mng phi c c lp v gii quyt c lp vi cc mng kh. y l mt c im quan trng cho cc LSP u cui u cui c xuyn hm trong cc LSP khc. Mt phng iu khin chung ca cc mng khc nhau ny phi c kh nng qun l mc tin cy trong mi mng.

S dng ti nguyn hiu qu

Vic qun l ti nguyn trong TDM v mng quang thng qua mt phng iu khin da trn IP i hi phi s dng ti nguyn hiu qu nh gp cc lin kt v s dng cc lin kt khng a ch.

Gp cc lin kt

Mt mng quang c hng nghn si quang song song, mi si quang li mang hng trm nghn bc sng gia hai nt. gim kch thc c s d liu lin kt v d m rng. GMPLS a ra khi nim gp cc lin kt (link bundling). Gp lin kt cho php nh x nhiu lin kt thnh mt v qung b cho OSPF hay IS IS. Mc d cng gin lc th c mt s thng tin b mt nhng gp lin kt gip gim ng k kch thc c s d liu trng thi lin kt v s lin kt phi qung b. Mt b cc lin kt ch cn mt knh iu khin nn gim c s lng thng ip phi trao i cho cc giao thc bo hiu v nh tuyn.

Cc lin kt khng a ch IP (Unnumbered link)

Thay v gn cc a ch IP khc nhau cho mi TDM hay cc lin kt mng, GMPLS dng lin kt khng a ch theo di cc loi lin kt ny. iu ny l cn thit v s lng knh TDM, bc sng v si quang tng nhanh trong khi vic qun l mi a ch IP tn nhiu thi gian v ti nguyn a ch l hu hn.Lin kt ny khng c a ch IP, thay vo n dng t hp router ID duy nht, v s lin kt biu din. Cc lin kt ny c xc nh trong mt phng bo hiu nh mt lin kt bnh thng c a ch IP.3.2.2 M hnh t chc mng GMPLS trong mng Metro

Cu trc phn lp mng Metro t chc thnh hai phn lp mng : Phn lp mng li ( Metro Core) v phn lp mng truy nhp ( Access Metro). Trong mi mt phn lp mng c cc thnh phn mng ch yu l cc phn t thuc mng nh tuyn/chuyn mch (Router/Switch) v cc phn t thuc mng truyn ti quang (TDM/OXC). Lp truyn ti mng truy nhp ch yu s dng cc phn t truyn ti da trn cng ngh TDM (cc thit b SDH-NG hoc cc thit b MSTP) v mt s hnh thc truy nhp khc. Lp mng truyn ti mng li c th s dng cc thit b OXC nu nh kch thc mng ln hoc s dng hn hp cc thit b TDM v OXC hay ch dng cc thit b TDM vi mng kch c trung bnh hoc nh. Tng t nh i vi mng ng trc, vic trin khai GMPLS trong mng Metro cng c th theo ba phng n t chc mng khc nhau: m hnh chng ln, m hnh ngang hng v m hnh lai ghp.

3.2.2.1 Phng n trin khai mng GMPLS Metro theo m hnh chng ln ( Overlay Model)

Mng Metro t chc theo m hnh chng ln v cu trc phn lp mng vn gm 2 lp mng : Lp mng li v lp mng truy nhp nh hnh 4. Mng truyn ti quang ca phn lp mng li Metro v mng truy nhp Metro bao gm cc phn t SDH NG / MSTP hoc cc phn t OXC kt ni vi nhau thong qua cc giao din I NNI. Ranh gii gia hai lp mng ny c kt ni vi nhau thng qua cc giao din E-NNI. V nh vy, mt phng iu khin qun l ca mng truyn ti quang v cc Router bin l mt mt phng thng nht theo cng ngh GMPLS. Cc giao din vt l kt ni thuc mng truyn ti c th l cc giao din STM-n, FE (100 Mbit/s), GE (1/10 Gbit/s) hoc cng c th l cc giao din vi tc lung VC-n n l hay chui lin kt lung (VC Concatenation) cung cp cc knh truyn ti vi nhiu tc khc nhau.

Hnh 3.6 T chc mng GMPLS Metro theo m hnh chng lnu im:-

To iu kin thun li cho vic kt ni cc phn t mng hoc mng cung cp cc loi hnh dch v khc nhau c cc h thng iu khin v qun l bng h thng c sn.

- Ph hp cho thc hin kt ni mng nh tuyn Router vi mng truyn ti quang c h thng nh tuyn, iu khin bo hiu ring r.

- Cho php trin khai m rng qun l mng truyn ti quang m khng nh hng ti mng nh tuyn Router hin c.

Nhc im:

- Hn ch hiu qu s dng ti nguyn chung ca mng do thng tin v nh tuyn v tnh trng ti nguyn ch c ngha trong phm vi mng GMPLS, c th l lp nh tuyn Router ch thc hin yu cu kt ni dch v vi lp truyn ti quang qua cc giao thc bo hiu m khng c quyn nhn v x l thng tin v ti nguyn trn mng.

- C ch thc hin qun l v iu khin cc s c h hng mng c th rt phc tp

- Khng ph hp vi mng c cu trc kt ni Mesh y

-

Khng thc hin chc nng thng nht iu khin, qun l (GMPLS) trn phm vi ton mng.

3.2.2.2 Phng n trin khai mng GMPLS Metro theo m hnh ngang hang ( Peer Model)V c bn cu trc kt ni ca m hnh mng ngang hng trong mng GMPLS Metro tng t nh m hnh mng ngang hng p dng cho ng trc nh hnh 5. Phng n trin khai mng ngang hng cho mng GMPLS Metro cho php to mt phng iu khin qun l thng nht theo b giao thc GMPLS ca IETF v m hnh kin trc mng ASON/ G.8080 do ITU-T xut.u im:-

Ti u ha vic chn la cc tuyn kt ni qua cc Router v cc SDH- NG/MSTP/OXC, khng pht sinh hin tng chng ln v cu trc t-p gia mng truyn ti quang v mng nh tuyn Router.

- Cho php s dng ti nguyn mng mt cch hiu qu trong mi trng khng ng nht cc thit b mng truyn ti quang v thit b nh tuyn Router.

- S dng mt mt iu khin v qun l thng nht cho cc phn t mng khc nhau trong phn lp truyn ti quang v nh tuyn Router.

-

D dng hn trong vic pht hin v iu khin cc s c trn mng hn hp IP v quang.

- Linh hot hn, mm do hn v nhanh chng hn trong vic tip cn vi khch hng

cung cp v kin to dch v.

Hnh 3.7 : T chc mng GMPLS Metro theo m hnh ngang hngNhc im- Khng h tr trong mi trng mng bao gm nhiu nh khai thc mng khc nhau do bn thn cc nh khai thc mng khng mun cc nh khai thc mng khc bit thng tin v mng ni b ca mnh.

3.2.2.3 Phng n trin khai mng GMPLS Metro theo m hnh lai ghp (Augmented Model)Trin khai mng GMPLS Metro theo m hnh lai ghp cng tng t nh trin khai mng GMPLS ng trc theo m hnh lai ghp. im khc bit y l phm vi mng GMPLS bao gm cc phn t mng truyn ti quang ca c hai phn lp mng truy nhp v mng li Metro ti cc Router bin ng vai tr cng lin kt vi mng nh tuyn IP/MPLS (Hnh 6). Cc Router bin thc hin hai chc nng: i vi phm vi mng GMPLS n hot ng nh mt phn t mng GMPLS kt ni vi cc phn t mng GMPLS khc thng qua giao din NNI (I-NNI hoc E-NNI) thc hin cc chc nng qun l, iu khin v nh tuyn trong mng GMPLS.

Hnh 3.8: T chc mng GMPLS Metro theo m hnh lai ghpu im:

- Tn dng c u im mng ngang hng xt v kha cnh qun l iu khin mng theo phm vi mng.

- C ch qun l v iu khin li mng n gin v c phn bit r ti ranh gii gia mng IP/MPLS v mng quang

-To thun li trong vic m rng mng quang t mng hin ti sang to mt phng

iu khin qun l thng nht.

- Vn tn ti hai mt phng iu khin qun l: Quang v mng nh tuyn IP/MPLS

-

Phng n ny khng ph hp vi mng c cu trc t-p tng ng gia mng truyn ti quang v mng nh tuyn Router IP/MPLS.

3.2.3 Kt hp ASON (Automatically Switched Optical Network)ASON l vit tt ca cm t Automatically Switched Optical Network, l mng quang th h mi c kh nng duy tr dch v trong trng hp c ng lm vic v ng bo v b gin on bng cch t ng tm v thit lp knh truyn dn m. Ni chung, mt mng gi l ASON khi n c kh nng t ng pht hin gy link, t ng cu hnh li topology ca mng.

V c bn, ASON l mng truyn dn ( SDH,xWDM,) c b sung mt phng iu khin GMPLS vi chc nng nh tuyn, bo hiu, iu khin chuyn mch, ASON c th c nng cp ln t mng truyn dn hin ti bng cch b sung mt phng iu khin ASON/GMPLS. Khi mng c nng cp, cc node mng c kh nng giao tip vi nhau t ng nhn bit hin trng mng, nh tuyn v iu khin kt ni cho ti cc node mng chuyn mch dch v sang ng mi.3.2.3.1 Cc chc nng chnh ca ASON

So vi mng SDH truyn thng, ASON c cc chc nng chnh nh:

T ng cu hnh dch v u cui end to end.

T ng pht hin si quang v dch v.

Cung cp tnh nng kt ni mng hnh li.

Cung cp nhiu kiu dch v vi cht lng v mc bo v khc nhau.

Cung cp kim sot lu lng vi cc u cu hnh mng.3.2.3.2 S kt hp cu trc ASON v b giao thc GMPLS

Cng ngh ASON ra i trn nn tng mt phng iu khin ASON/MPLS.Vic tiu chun ha mt phng iu khin c hai li ch:

Cho php cc mng quang t ng c th c xy dng t cc thit b t cc nh cung cp khc nhau.

Ch r mt tp ti thiu cc tnh nng m thit b ph hp theo tiu chun s phi h tr. Cc li ch ny s gim gi thnh pht trin v khai thc mng cho khch hang l cc nh iu hnh mng v cung cp dch v. Vic nh ngha cc tiu chun cho mt phng iu khin c thc hin c lp bi hai t chc tiu chun:

Hip hi vin thng quc t (International Telecomunication Union ITU T), pht trin kin trc ca cc mng quang chuyn mch t ng Automatically Switched Optical Network (ASON ).

Lc lng chuyn trch Internet (Internet Engineering Task Force IETF ), pht trin chuyn mch a giao thc tng qut ha ( Generalized Multi Protocol Label Switching (or GMPLS).

ITU a ra cc yu cu v kin trc da trn yu cu cc thnh vin. Mt mc ch thy r l trnh vic pht trin cc giao thc mi trong mng khi cc giao thc c ang tn ti vn m bo c. S pht trin ca GMPLS trong IETF

GMPLS c pht trin t MPLS, mt cng ngh mch gi c thit k ci thin hiu qu ca cc mng s liu. l mt s b xung ca MPLS, cn c gi l MPLS TE, h tr vic cung cp kt ni end to end s dng bo hiu vi nh tuyn trn c s cng bc. l s pht trin t nhin tng qut ha v m rng nhm thch ng vi cc cng ngh chuyn mch quang nh hng ( circuit oriented ) nh ghp knh phn chia theo bc sng v thi gian (TDM v DWDM).

Thut ng, GMPLS thng c s dng ch mt tp giao thc hot ng cng nhau cng cung cp mt s cng tc t u cui ti u cui trong cng mt mng quang. Cc giao thc bao gm :

Generalized RSVP TE dng cho bo hiu

Generalized CR LDP cng dng cho bo hiu.

OSPF vi phn m rng TE cho nh tuyn ni vng.

ISIS vi phn m rng TE cng nh tuyn ni vng.

LMP v LMP WDM cho cc chc nng pht hin v qun l cc lien kt hn hp.

RSVP TE v CR LDP l cc giao thc khc nhau nhng hot ng vi cng mc ch. Hai giao thc ny c k tha t MPLS TE3.2.3.3 S pht trin ca ASON trong ITU

ASON c pht trin bi nhm nghin cu 15 ca ITU T. D n ny thc hin nhm p ng nhu cu ca cc thnh vin ITU to ra mt nh ngha y v hot ng ca cc mng truyn dn chuyn mch t ng bao gm mt phng s liu, iu khin, qun l.

ASON khng phi l mt giao thc hay mt tp giao thc. l mt cu trc, trong nh ngha cc thnh phn trong mt mt phng iu khin quang v tng tc gia chng. ASON cn ch ra cc tng tc ny ti vng gip danh gia cc nh cung cp khc nhau v v th cc giao thc yu cu phi c chun ha cc nh cung cp hay cc nh khai thc mng t a ra (value add).

Cc tiu chun cn bn lin quan n ASON bao gm:

Cu trc ca cc mng quang chuyn mch t ng Architecture for Automatically Switched Optical Networks ( G.8080 trc y l G.ason)

iu khin kt ni v cuc gi phn b - Distributed Call and Connection Control (G.7713, trc y l G.dccm), bao gm c phn bo hiu.

Cu trc v yu cu i vi nh tuyn trong cc mng quang chuyn mch t ng Architecture and Requirements for Routing in the Automatic Switched Optical Networks (G.7715, trc y l G.rtg).

Cc k thut nhn bit t ng tng qut Generalized Automated Discovery Techniques (G.7714, trc y l G.disc)

Hnh 3.9 Cc khuyn ngh ca ITU T v ASON.

KT LUN

Sau mt thi gian tm hiu v cng ngh chuyn mch nhn a giao thc MPLS v tm hiu ng dng ca MPLS VPN, nhm sinh vin thc hin chng em thu c nhng kt qu nh sau

Hiu c nhng kh khn v tn ti hin c ca cc cng ngh chuyn mch truyn thng v s cn thit phi ra i cng ngh MPLS. Hiu c kin trc mt mng MPLS, qu trnh chuyn mch nhn, to nhn. Cc ch hot ng khc nhau ca MPLS Cc mode hot ng khc nhau ca MPLS, cc ng dng ca chuyn mch nhn a giao thc, trong ni bt l ng dng VPN trong MPLS.

Hiu v cng ngh VPN, cc giao thc dung trong VPN, tm hiu IP Sec, cc bc hot ng ca IP Sec.

Hiu c m hnh mng MPLS VPN, m hnh MPLS VPN lp 2 v MPLS VPN lp 3, u im cng nh nhng tn ti ca chng.

Nm bt c vn bo mt trong MPLS VPN v cht lng dch v, nhng nguy c m mt m hnh MPLS VPN gp phi. C hi v xu hng ca nh cung cp dch v khi trin khai MPLS VPN

Nhn thy, MPLS VPN l mt cng ngh c nhiu u im v chc chn s cng ngy c nhiu doanh nghip la chn trin khai, MPLS VPN s c mt th trng rng ln.

Tuy nhin, y l mt ti ln, i hi s hiu bit su rng, cng nh thi gian tm hiu lu di. Do chc chn khng trnh khi thiu st trong khun kh lun vn ny, rt mong c s gp t pha cc thy c v bn b.

Xin chn thnh cm n!TI LIU THAM KHO[1] Chuyn mch nhn a giao thc MPLS TS.Trn Cng Hng NXB Bu in 2008

[2] Cisco System, Inc Advanced MPLS VPN Solution 2000

[3] Chuck Semeria RFC 2547 bis: BGP/MPLS VPN Fundamentals Jupiter Networks, Inc.

[4] Jim, Guichard, Ivan - MPLS and VPN Architectures Cisco Press, 2000.

[5] Michael H.Behringer, Monique J. Morrow MPLS VPN Security- Cisco Press, June 08 2005

Hnh 3.4 nh hng t chc mng th h k tip NGN ca Tng cng ty BCVT Vit Nam

Nhm sinh vin thc hin: Nhm 07Page - 3 -PAGE Nhm sinh vin thc hin: Nhm 07Page - 40 -

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DLCI

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Tiu gi PPP trn SDH

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VPI/VCI

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