Thiet Ke Mo Hinh Mang ATM MPLS

8/14/2019 Thiet Ke Mo Hinh Mang ATM MPLS

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Thit k m hnh mng ATM MPLS

ng Th Tho Tr ng i hc Cng ngh 1

I HC QUC GIA H NI

TRng i hc cng ngh

L ng Th Tho

THIt k m hnh mng atm mpls

Kho lun tt nghip i hc h chnh quy

Ngnh:in t - Vin thng

H ni - 2005


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Li cm n

Em xin by t lng knh trng v bit n su sc ti thy gio

PGS.TS Nguyn Kim Giao tn tnh ch bo v gip em hon

thnh tt kho lun tt nghip ny. ng thi em xin c cm n cc

thy c gio tr ng i hc Cng ngh - i hc Quc Gia H Ni,

nhng ng i trang b cho em nhng kin thc gip em hon thnh tt

kho lun tt nghip ny.

H N i, thng 6 nm 2005Sinh vin

Lung Th Tho



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Tm tt ni dung

Hin nay, mng Inernet truyn thng khng th p ng cc nhu cu ngycng tng nhanh ca khch hng v khng c bt k c ch iu khin cht l ngno, khng h tr tt cht l ng dch v v khng cung cp hiu qu mng ringo. Gn y, cng ngh chuyn mch nhn a giao thc (MPLS) c xut s dng ti cc gi tin IP trn cc knh o, MPLS kt hp c cc u im cachuyn mch gi datagram v chuyn mch knh o v khc phc c cc nh cim trn ca mng truyn thng. Do vy, trong ti lun vn ny, em mun gii

thiu v cng ngh MPLS. Tuy nhin tn dng c s h tng ca cng nghATM hin ti - cng ngh tin cy c kim chng qua thc t v tng b c tinti mng MPLS hon ton, lun vn tp trung nghin cu v cc gii php thit k mng ATM MPLS. c bit bi bo co nghin cu thit k m hnh m phngmng ATM MPLS c th ng dng trong nhng iu kin Vit Nam, cng nh phc v cho o to ti b mn Vin Thng - tr ng i hc Cng Ngh -

HQGHN.



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MC LC

TrangLi m u .........................................................................................................Ch ng 1. Gii thiu v cng ngh MPLS .................................................... 3

1.1 Gii thiu .........................................................................................................31.1.1 Khi nim MPLS .....................................................................................41.1.2 S ra i ca MPLS .................................................................................4

1.2 Tnh hnh trin khai v qu trnh chun ho v MPLS .............................71.2.1 Tnh hnh trin khai MPLS ......................................................................7

1.2.2 Qu trnh chun ho v MPLS .................................................................81.3 Cc u im v ng dng ca MPLS ............................................................9

1.3.1 u im ...................................................................................................91.3.2 ng dng ................................................................................................10

1.4 Tm tt ch ng .............................................................................................11

CHNG 2. Cc thnh phn v hot ng ca mng MPLS..122.1 Cc khi nim c bn ca MPLS ....................................................................122.2 Cc thnh phn c bn ca MPLS ..................................................................15

2.3 Cc giao thc c bn ca MPLS .....................................................................16 2.3.1 Giao thc phn b nhn LDP ...........................................................162.3.2 Giao thc CR-LDP ..............................................................................17 2.3.3 Giao thc RSVP ..................................................................................17 2.3.4 Giao thc MPLS-BGP .........................................................................17 2.3.5 Kin trc h thng giao thc MPLS ...................................................17

2.4 Hot ng ca MPLS ......................................................................................192.4.1 Chuyn mch nhn .............................................................................192.4.2 hnh mng MPLS ..........................................................................20 2.4.3 Cc b c hot ng ca MPLS ...........................................................20 2.4.4 Cc ng hm trong MPLS ...............................................................23

2.5 Trin khai ng dng cng ngh MPLS ti Vit Nam .....................................242.5.1 Kh nng ng dng ca MPLS ...........................................................25 2.5.2 Mt s nguyn tc khi trin khai mng NGN......................................252.5.3 M hnh mng MPLS ..........................................................................26

2.6 Tm tt ch ng ..............................................................................................27CHNG 3: Thit k mng ATM MPLS ...................................................... 28

3.1 Gii thiu ........................................................................................................283.1.1 M hnh chc nng mng NGN ..........................................................293.1.2 Chuyn mch th v thut ng ............................................................30



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3.1.3 Cc cu trc chung ca MPLs .............................................................313.1.4 MPLS v cc kt hp IP trn ATM khc ............................................323.1.5 Cc b c thit k mng ATM MPLS ................................................33

3.2 Chn thit b MPLS .......................................................................................343.2.1 Cu trc mng MPLS .........................................................................343.2.2 Chn thit b MPLS Cisco .................................................................383.2.3 IP+ATM .............................................................................................45

3.3 Thit k mng ATM MPLS ...........................................................................483.3.1 Cu trc cc im truy nhp dch v PoP...........................................483.3.2 Xc nh cc ng lin kt ca mng ATM MPLS.............................533.3.3 nh tuyn IP trong mng ATM MPLS ................................................63

3.3.4 Xc nh khng gian knh o VC nhn MPLS ..................................663.3.5 Thit k mng lin tc ...........................................................................803.4 ng dng m hnh ATM MPLS trong gii php ca Nortel ..........................803.5 Tm tt ch ng ..............................................................................................82

CHNG 4. Trin khai ng dng ca mng ATM MPLS ....................... . 834.1 Cc tiu ch xy dng mng vin thng ng dng trong o to ............... ..834.2 Xy dng m hnh mng vin thng ng dng trong o to .......................844.3 Nhn xt ............. ...........................................................................................89

4.5 Tm tt ch ng .. ...........................................................................................90KT LUN .............................................................................................................Ti liu tham kho ..........................................................................................92



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THUT NG VIT TT

Vit tt Ting Anh Ting vit

ATM Aysnchronous Transfer Mode

Ph ng thc truyn tin khngng b

ASBP B nh tuyn ng bin h thng t tr BGP

BGP Border Gateway Protocol Giao thc nh tuyn ging nh giaothc cng bin

CLNP Connectionless Network Protocol

Giao thc mng khng k t ni

CR-LDP

Constraint-Based Routing-LDP

Giao thc phn phi nhnnh tuynda trn rng buc

CSR Cell Switching Router B nh tuyn chuyn mch tbo

DLCI Data Link ConnectionIdentifier Nhn dng k t ni l p lin k t d liu

DWDM Dense Wavelength DivionMultiplexing

Ghp knh phn chia theo b c sngmt cao

FEC Forwarding EquivalenceClass

L p chuyn ti p t ng ng

FIB Forwarding InformationBase

C s d liu chuyn ti p trong b nhtuyn

GMPLS Generalized Multi ProtocolLabel Switching

Chuyn mch nhna giao thc tngqut

IEIF Internation Engineering Task Force

Tchc tiu chun k thut Quc t Internet

IGP Interior Gateway Protocol Giao thc nh tuyn trong min



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IMA H p knho trn ATM

IP Internet Protocol Giao thc Internet

IS-IS Intermedia System toIntermedia System

Giao thc nh tuyn mng trung giant i mng trung gian

IS-IS-TE

Intermedia System toIntermedia System TrafficEngineer

Giao thc IS-IS c k tht lu l ng

LAN Local Area Network Mng cc b

LDP Label Distribution Protocol Giao thc phn phi nhn

LER Label Edge Router B nh tuyn bin nhn

LFIB Label ForwardingInformation Base

C s thng tin chuyn ti p nhn

LIB Label Information Base C s thng tin nhn

LMP Link Management Protocol Giao thc qun l knh

LSC B iu khin chuyn mch nhn

LSP Label Switched Path ng chuyn mch nhn

LSR Label Switching Router B nh tuyn chuyn mch nhn

MPLS Multi Protocol LabelSwitching

Chuyn mch nhna giao thc

NGN Next Generation Network Mng thhsau

OSPF Open Shortest Path First Giao thc nh tuyn m r ng theo ph ng thc u tin tuyn ng ngnnht

OXC Optical Cross-Connect u ni ghp quang

PNNI Private Node to NodeInterface

Giao din nt nt ring



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PPP Point to Point Protocol Giao thc im im

QoS Quanlity of Service Cht l ng dch v

RIP Realtime Internet Protocol Giao thc bo hiu IP th i gian thc

RSVP Resource ReservationProtocol

Giao thc dnh tr c ti nguyn

SDH Synchronous DigitalHierachy

Phn c p truyn dn s ng b

SONET Synchronous Optical Network

Mng quangng b

TCP Transport Control Protocol Giao thc iu khin truyn ti

TDP Tag Distribution Protocol Giao thc phn b th

TE Traffic Engineering iu khin lu l ng

UDP User Data Protocol Giao thc d liu ng i s dng

VC Virtual connection K t ni o

VCI Virtual Circuit Identifier Nhn dng ngo trong tbo

VP Virtual Path Knho

VPI Virtual Path Identifier Nhn dng knho trong tbo

VPN Virtual Private Network Mng ringo

WAN Wide Area Network Mng din r ng



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Li m u

Nn tng cho x hi thng tin chnh l s pht trin cao ca cc dch v vin

thng. Mm do, linh hot, v gn gi v i ng i s dng l mc tiu cn h ng t i.Vi nm qua, Internetang ngy cng pht trin v i ccng dng m i trong th ngmi v th tr ng ng i tiu dng. Cng v i cc dch v truyn thng hin nay ccung c p qua Internet th cc dch v thoi v a ph ng tin ang c pht trin vs dng. Tuy nhin, tc v di thng ca cc dch v vng dng ny v t quti nguyn h tng Internet hin nay. Chnh nhng iu gy mt p lc cho mngvin thng hin th i, phi m bo truyn ti thng tin tc cao v i gi thnh h. gc khc s ra i ca nhng dch v m i nyi hi phi c cng ngh thc thitin tin.

u im ni bt ca giao thc nh tuyn TCP/IP l kh nng nh tuyn vtruyn gi tin mt cch ht sc mm do linh hot v r ng kh p ton cu. Nhng IPkhngm bo cht l ng dch v, tc truyn tin theo yu cu, trong khi cngnghATM c thmnh u vit v tc truyn tin cao,m bo th i gian thc vcht l ng dch v theo yu cu nh tr c. S k t h p IP v i ATM c th l gii phpk vng cho mng vin thng t ng lai - mng thhsau NGN.

Gn y, cng ngh chuyn mch nhna giao thc (MPLS) c xut ti cc gi tin trn cc knho v khc phc c cc vn m mng ngy nayang phi i mt, l tc , kh nng m r ng c p mng, qun l cht l ng, qunl bng thng cho mng IP thh sau - da trn mng ng tr c v c thhot ngv i cc mng Frame Relay v ch truyn ti khngng b (ATM) hin nay png cc nhu cu dch v ca ng i s dng mng.

Ngy nay, nhng xu h ng pht trin cng ngh vang ti p cn nhau,an

xen ln nhau cho php mng l i tha mn tt h n cc nhu cu ca khch hng trongt ng lai. Th tr ng vin thng trn th gi i ang ng trong xu th cnh tranh v pht trin h ng t i mng vin thng hi t ton cu to ra kh nng k t ni a dchv trn phm vi ton thgi i. Do vy, png c cc nhu cu , s ra i caMPLS l tt yu.

Tuy nhin, hin ti vn cha r rng liu MPLS cpng c hay khngihi v cht l ng dch v - QoS m ATM khng nh v tr ca mnh. ATM cho

n gi vn l cng nghduy nht c kim nghim v thnh cng trong vic tch



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h p d liu, thoi, v video trn cng mt mng. Hin ti th mt gii php k t h p anton kh thi l chy cATM v MPLS trn mng ng tr c.

V i ngh a cng vic nghin cu tm hiu vnh gi cc gii php thit k

mng ATM MPLS c tin hnh trong lun vn ny l r t cn thit, c bit khi xuthmng NGN (mng th h sau) hi t ton cu to ra kh nng k t ni a dch v trn phm vi ton th gi i. V i ton b ni dung trnh by trong lun vn ny, timong mun c ti p tc nghin cu vvn ny nhm tham gia v traoi vn thit k trong l nh vc mng thhsau cn r t r ng l n v h p dn.

Mc ch ca ti lun vn l nghin cu tm hiu cng nghMPLS tint i thit k mng ATM MPLS c th a vong dng trong nhng iu kin c th

ti Vit Nam v cng nh phc v cho o to v cng ngh mng vin thng titr ng i hc Cng ngh - HQGHN. V i mc tiu ni dung ca lun vn gmcc vn sau:

Ch ng 1: Gi i thiu t ng quan v cng ngh chuy n mch nhn a giao th c(MPLS) .

Ch ng 2: Gi i thiu cc thnh ph n v ho t ng ca mng MPLS .

Ch ng 3: Thi t k mng ATM MPLS .

Ch ng 4: Tri n khai ng d ng ca mng ATM MPLS trong o t o .



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Ch ng 1: Gii thiu Cng ngh MPLS1.1 Gi i thiu

Trong nhng nm gn y, mng Internet pht trin nhanh v tr nn r t ph bin, Internet m ra mt ph ng tin thng tin r t hiu qu v tin l i phc v chogio dc, th ng mi, gii tr, thng tin gia cc cng ng .v.v Hin nay ngy cng pht trin ccng dng m i c trong th ng mi v th tr ng ng i tiu dng. Thmvo cc dch v a ph ng tin ang c pht trin v trin khai thcy nhu cuv tc v di bng tng nhanh. Cng v i n s l ng ng i s dng ngy cngtng, cht l ng ng i s dng phi c nng cao. Tuy nhin, ti nguyn h tngInternet hin nay khngpng c cc nhu cu .

S ra i ca chuyn mch nhna giao thc MPLS l tt yu khi nhu cu vtc pht trin r t nhanh ca mng Internet yu cu phi c mt giao thc m i m bo cht l ng dch v theo yu cu ng th i phi n gin v tc x l phi r tcao.

Tht vy, MPLS cung c p mt nn tng cng nghm i cho qu trnh to ra ccmng a ng i dng,a dch v v i hiu nng cao h n, kh nng m r ng mng l n,nhiu chc nng c ci tin vp ng c nhiu yu cu v cht l ng dch v.Chuyn mch nhn l yu tquan tr ng nht cho qu trnh m r ng Internet, n cungc p nhng ng dng quan tr ng trong x l chuyn ti p gi bng cch n gin haqu trnh x l, hn chvic to ra cc bn sao mou ti mi b c trong ng dn,v to ra mt mi tr ng c th h tr cho iu khin cht l ng dch v. Pht trinca MPLS cho php tch h p IP v ATM, h r hi t dch v v cung c p nhng c hi m i choiu khin lu l ng v mng ringo. Hiu nng x l gi c th cci tin bng cch thm nhn c kch th c c nh vo cc gi.iu khin cht l ng

dch c th c cung c p d dng h n v c th xy dng cc mng cng cng r tl n. MPLS l mt k thut m i c mong i s pht trin ph bin trn phm vir ng c cc mng IP ring v cng cng, m ng cho vic hi t cc dch v mng, video v thoi.

Tm li, MPLS s ng mt vai tr quan tr ng trong vic nh tuyn, chuynmch v chuyn ti p cc gi qua mng thh sau cng nh gii quyt cc vn linquan t i kh nng m r ng c p v c th hot ng v i cc mng Frame relay vATM hin nay png cc nhu cu dch v ca ng i s dng mng.



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1.1.1 Khi nim cng nghchuyn mch nhn a giao th c MPLS

Chuyn mch nhna giao thc - MPLS (MultiProtocol Label Switching) lmt bin php linh hot gii quyt nhng vn g p nhiu kh khn trong mng

hin nay nh: tc , quy m, cht l ng dch v (QoS), qun tr v k thut lul ng. MPLS thhin mt gii php thng minh png nhng i hi dch v vqun l di thng cho mng IP th h sau - da trn mng ng tr c. MPLS giiquyt nhng vn lin quann tnh quy m vnh tuyn (da trn QoS v dngcht l ng dch v) v c th tn ti trn mng ATM (ph ng thc truyn khngng b - Asynchronous Tranfer Mode) v mng Frame-relayang tn ti.

MPLS th c hi n m t s ch c n ng sau:

Xcnh c cu qun l nhiu mc khc nhau ca cc lung lu l ng,nh cc lung gia cc c cu, phn cng khc nhau hoc thm ch cc lung gianhngng dng khc nhau.

Duy tr s c l p ca cc giao thc l p 2 v l p 3.

Cung c p ph ng php nh x a ch IP v i cc nhn n gin, cdic nh c s dng b i cc cng ngh chuyn ti p gi v chuyn mch gi khcnhau.

Giao din v i cc giao thc nh tuyn hin c nh giao thc t tr c tinguyn (RSVP) v giao thc m r ng theo ph ng thc u tin tuyn ng ngnnht (OSPF).

H tr IP, ATM v giao thc l p 2 Frame-relay.

1.1.2 S ra i ca MPLS

MPLS l k t h p mt cch hon ho ccu im ca cng ngh IP v ATM

a) Cng ngh IP

IP (Giao thc Internet Internet Protocol) l thnh phn chnh ca kin trcmng Internet. IPnh ngh a c cu nh s, c cu chuyn tin, c cu nh tuyn vcc chc nng iu khin mc th p (Giao thc bn tiniu khin Internet - ICMP).Gi tin IP gm a ch ca bn nhn; a ch l mt s duy nht trong ton mng vmangy thng tin cn cho vic chuyn gi tin t i ch.

C cu nh tuyn c nhim v tnh ton ng i t i cc nt trongmng. Do vy, c cu nh tuyn phi c c p nht cc thng tin v hnh mng,



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thng tin vnguyn tc chuyn tin (nh trong Giao thc nh tuyn bin min - BGP)v n phi c kh nng hot ng trong mi tr ng mng gm nhiu nt. K t qu tnhton ca c cu nh tuyn c lu trong cc bng chuyn tin cha thng tin v

chng ti p theoc thgi gi tin t i h ng ch.Da trn cc bng chuyn tin, c cu chuyn tin chuyn mch cc gi IP

h ng t i ch. Ph ng thc chuyn tin truyn thng l theo tng chng mt. cchny, mi nt mng phi tnh ton bng chuyn tin mt cchc l p. Do vy, ph ngthc ny yu cu k t qu tnh ton ca phn nh tuyn ti tt c cc nt phi nhtqun v i nhau. S khng thng nht ca k t qunyng ngh a v i vic mt gi tin.

Kiu chuyn tin theo tng chng hn chkhnng ca mng. V d, v i

ph ng thc ny, nu cc gi tin chuyn t i cng mt a ch mi qua cng mt ntth chng s c truyn qua cng mt tuyn t i im ch. iu ny khin mngkhng th thc hin mt s chc nng khc nh nh tuyn theoch, theo loi hnhdch v .v.v

Tuy nhin, bn cnh , ph ng thc nh tuyn v chuyn tin ny nngcao tin cy cng nh kh nng m r ng ca mng. Giao thc nh tuyn ng cho php mng phn ng li v i s c bng vic thayi tuyn khi b nh tuyn bit c s thayi v hnh mng thng qua vic c p nht thng tin v tr ng thi k tni. V i cc ph ng thc nh nh tuyn lin min khng phn c p (ClasslessInterDomain Routing - CIDR), kch th c ca bng chuyn tin c duy tr mcch p nhn c v vic tnh tonnh tuyn u do cc nt t thc hin, mng c th c m r ng m khng cn thc hin bt k mt thayi no.

Tm li, IP l mt giao thc chuyn mch gi ctin cy v kh nngm r ng cao. Nhng vic iu khin lu l ng r t kh thc hin do ph ng thc nhtuyn theo tng chng.Ngoi ra, IP khng h tr cht l ng dch v.

b) Cng ngh ATM

Cng ngh ATM (Aysnchronous Transfer Mode ph ng thc truyn tinkhngng b) l mt k thut truyn tin tc cao.ATM nhn thng tin nhiudng khc nhau nh thoi, s liu, video v ct ra thnh nhiu phn nhgi l tbo.Cc t bo ny, sau, c truyn qua cc k t ni o VC (Virtual connection). VATM c thh tr thoi, s liu v video v i cht l ng dch v trn nhiu cng ngh bng r ng khc nhau, n c coi l cng ngh chuyn mch hngu v thu ht

c nhiu quan tm.



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ATM khc v i nh tuyn IP mt s im. N l cng ngh chuyn mchh ng k t ni. K t ni t im u n im cui phi c thit l p tr c khi thngtin c gi i. ATM yu cu k t ni phi c thit l p bng nhn cng hoc thit

l p mt cch t ng thng qua bo hiu. Mt im khc nhau na l ATM khngthc hin nh tuyn ti cc nt trung gian. Tuyn k t ni xuyn sut c xcnhtr c khi traoi d liu v c gi c nh trong th i gian k t ni. Trong qu trnhthit l p k t ni, cc tng i ATM trung gian c p cho k t ni mt nhn. Vic ny thchin haiiu: dnh cho k t ni mt s ti nguyn v xy dng bng chuyn tbo timi tng i. Bng chuyn tbo ny c tnh cc b v ch cha thng tin v cc k tni ang hot ng i qua tng i. iu ny khc v i thng tin v ton mng chatrong bng chuyn tin ca b nh tuyn dng IP.

Qu trnh chuyn tbo qua tng i ATM cng t ng t nh vic chuyn gitin qua b nh tuyn. Tuy nhin, ATM c th chuyn mch nhanh h n v nhn gntrn cc tbo c kch th c c nh (nhh n ca IP), kch th c ca bngnh tuynnh h n nhiu so v i b nh tuyn IP, v vic ny c thc hin trn cc thit b phn cng chuyn dng. Do vy, thng l ng ca tng i ATM th ng l n h nthng l ng ca b nh tuyn IP truyn thng.

Ni cch khc, cng nghATM l mt k thut truyn tin tc cao,m bo

th i gian thc v cht l ng dch v theo yu cu nh tr c.c) Cng ngh MPL S - K t h p gi a cng ngh IP v ATM

u im ni bt ca giao thc nh tuyn TCP/IP l kh nng nh tuyn vtruyn gi tin mt cch ht sc mm do linh hot v r ng kh p ton cu. Nhng IPkhngm bo cht l ng dch v, tc truyn tin theo yu cu, trong khi cngnghATM c th mnh u vit v tc truyn tin cao,m bo th i gian thc vcht l ng dch v theo yu cu nh tr c. S k t h p IP v i ATM c th l gii php

k vng cho mng vin thng t ng lai - mng thhsau NGN.Chuyn mch nhna giao thc - MPLSp ng c nhu cu . MPLS

k t h p ccu im ca cng ngh IP v ATM to ra mt gii php linh hot cho vicgii quyt cc vn m cc mng ngy nayang phi i mt, l tc , khnngm r ng c p mng, qun l cht l ng dch v (QoS) v k thut lu l ng.

Tht vy, cng nghChuyn mch nhna giao thc MPLS l k t qu phttrin ca nhiu cng ngh chuyn mch IP s dng c ch hon i nhn nh ca



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ATMtng tc truyn gi tin m khng cn thayi cc giao thc nh tuyn caIP. T t ng khia ra MPLS l: nh tuy n t i bin, chuy n mch li.

Trong cc mng MPLS, cc gi c gn nhn ti bin ca mng v chng

c nh tuyn xuyn qua mng da trn cc nhn n gin. Ph ng php ny cho phpnh tuyn r rng vi x phn lit cc gi trong khi vn gi c cc b nhtuyn li n gin.

C th ni MPLS l mt cng ngh chuyn mch IP c nhiu trin vng.V itnh cht c cu nh tuyn ca mnh, MPLS c kh nng nng cao cht l ng dch v ca mng IP truyn thng. Bn cnh , thng tin lu l ng ca mng s c cithin r r t.

1.2 Tnh hnh trin khai cng ngh v qu trnh chun ho v MPLS

1.2.1 Tnh hnh trin khai cng nghMPLS

BIG PIPE nh khai thc mng tr c IP ca Canada la chn Cisco Systems lnh cung c p thit b cho mng tr c IP OC-192 vo thng 10 nm 2001- cc b nhtuyn ca Cisco trong mng tr c ny scho php BIG PIPE cung c p bng thng OC-192. Cc b nh tuyn 12410 v 12416 ca Cisco s cho php nh cung c p dch v ny trin khai cc dch v IP th h sau nh MPLS-VPN, IP QoS v Voice over IP(VOIP).

Juniper Network v Ericsson Communication thng bo r ng th h InternetRouter tr c m i (serie M) c trin khai trong mng tr c m i ca TelstraSaturn.TelstraSaturn l cng tyu tin ti New Zealand trin khai mng bng tn l n nhtcung c p c IP v thoi. Cc b nh tuyn M160 v M20 c trin khai trongmng tr c ti lu l ng qua MPLS.y l mng th ng mi u tin trin khaiy

STM-16 (2.5 Gb/s) ti New Zealand.Thng 10 Alcatel thng bo k h p ng cung c p thit b bng r ng cho

Deatsche Telecom Group. Cc sn phm ca Alcatel bao gm: thit b chuyn mchnh tuyn (RSP) 7670 cho mng chuyn i s liu ATM ca quc ni ti c. Thit b ny s cho php Deatsche Telecom m r ng mng a dch v ca h t 12.8 Gb/sln 450 Gb/s thomn nhu cu trong mng thc. Thit b ny c kh nng chuynmch MPLs trn ATM.



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NTT America thng bo trin khai dch vArestar Global IP-VPNn tt c cc doanh nghi p ti M. Dch vArestar IP-VPN cung c p gii php hon chnh baogm nhiu cng ngh IP VPN, MPLS.

China Telecom la chn Nortelworks trong 2 h p ng tr ga 12 triu USD nng c p mng ATMa dch v ti tnh Jiasngu v Shandong vo thng 10 nm 2001.Hai mng ny cho php China Telecom cung c p dch v ATM tin tin, duy nht.China Telecom c k hoch thay thcc thit b chuyn mch ng tr c hin ti bnggii php ca Nortel Network. Cc thit b bao gm: Passport 15000, Passport 7480MS. Cc thit b ny cung c p cc dch vATM, Frame Relay, Chuyn mch vnhtuyn IP, MPLS

Riverstone Network trin khai mng cho hai nh cung c p Chu u lTelenet - nh cung c p dch vB v Neosnetwork - nh khai thc ca U.K. Nh khaithc ny trin khai mng MPLSu tin ti U.K v i Router loi RS. Neosnetworkschn RS 8600 multi-service router v RS 3000 metro access router cung c p dchv Ethernet nh mt phn trong mng truyn s liu ton quc ca U.K. Telenet lachn Reverstone l nh cung c p cc router cho mng ng tr c IP trong mngtruyn s liu v mng cp ca mnh. Telenet s dng Reverstone RS 8600 multi-service mto routers. Chai d n nyu c trin khai cui nm 2001.

Alcatel thng bo thng 10 nm 2001 sn phm Alcatel 7670 RSP c lachn m r ng mng ATM ton quc ca Belgacom. Sn phm ny cho phpBelgacom m r ng mng ATMa dch v hin ti, Belgacom s trin khai thmcc tng i truy nh p Alcatel 7470 MSP ti lu l ng IP v cc dch v DSL.Trong nm 2001, Belgacom tng s l ng khch hng truy nh p Internet ln100.000 trong thng 7 v ln t i 200.000 vo cui nm. Thit b a giao thcAlcatel 7670 RSP l thit b MPLS cho php tch h p ATM v MPLS/IP trong mt

thit b duy nht.1.2.2 Qu trnh chun ha MPLS

i v i cc cng nghchuyn mch m i, vic tiu chun ho l mt kha cnhquan tr ng quyt nh kh nng chim l nh th tr ng nhanh chng ca cng ngh .Cc tiu chun lin quann IP v ATM c xy dng v hon thin trong mtth i gian t ng i di. Cc tiu chun vMPLS ch yu c IETF pht trin (cctiu chun RFC Request for Comment) hin ang c hon thin v thc hin

theo mt qu trnh nh sau:



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Vou nm 1997, hin ch ng MPLS c thng qua. Vo thng 4 nm 1997, nhm lm vic MPLS tin hnh cuc h p u tin. Vo thng 11 nm 1997, ti liu MPLS c ban hnh.

Vo thng 7 nm 1998, ti liu cu trc MPLS c ban hnh. Trong thng 8 v thng 9 nm 1998, 10 ti liu Internet b sung c ban

hnh, bao gm giao thc phn phi nhn MPLS (MPLS Label Distribution Protocol MPLS LDP), m hanh du (Mark Encoding), ccng dng ATM,v.v MPLShnh thnh vcn bn.

IETF hon thin cc tiu chun MPLS va ra cc ti liu RFC trong nm1999.

Qu trnh chun ho MPLS cn do ITU-T xy dng v pht trin. Nh vy, c th thy r ng MPLS pht trin nhanh chng v hiu qu.

iu ny cng chng minh nhng yu cu c p bch trong cng nghi p cho mtcng ngh m i. Hu ht cc tiu chun MPLS hin ti c ban hnh d idng RFC.

1.3 Mt s u im v ng dng ca cng nghMPLS

1.3.1 Cc u im ca MPLS

Mc d thc t r ng MPLS banu c pht trin v i mc chgii quytvic chuyn ti p gi tin, nhng l i im chnh ca MPLS trong mi tr ng mng hinti li t khnng iu khin lu l ng ca n. Mt s l i ch ca MPLS:

Htr mm do cho tt ccc dch v (hin ti v s p t i) trn mt mng n. n gin hahnh v cu hnh mng khi so v i gii php IP qua ATM. H tr tt c cc cng c iu khin lu l ng mnh m bao gm c nh

tuyn lin ti p v chuyn mch bo v. H tr a k t ni v a giao thc: thit b chuyn ti p chuyn mch nhn cth c dng khi thc hin chuyn mch nhn v i IP cng tt nh v i IPX. Chuynmch nhn cng c thvn hnho trn bt k giao thc l p lin k t d liu.

Kh nng m r ng: chuyn mch nhn cng cu im v tc gia chcnng iu khin v chuyn ti p. Mi phn c th pht trin khng cn n cc phnkhc, to s pht trin mng ddng h n, gi thnh th p h n v li t h n.



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H tr cho tt c cc loi lu l ng: mt u im khc ca chuyn mchnhn l n c thh tr cho tt c cc loi chuyn ti p unicast, loi dch v unicast vcc gi multicast.

1.3.2 Cc ng dng ca MPLSMng MPLS c nhiu ng dng trong c 3ng dng chnh v thng th ng

2 trong c3 khnng c s dng ng th i:

Tch h p IP+ATM - Do chuyn mch nhn c th thc hin c b i ccchuyn mch ATM, MPLS l mt ph ng php tch h p cc dch v IP tr c ti p trnchuyn mch ATM. S tch h p ny cn phi t nh tuyn IP v phn mm LDPtr c ti p trn chuyn mch ATM. Do tch h p hon ton IP trn chuyn mch ATM,MPLS cho php chuyn mch ATM h tr ti u cc dch v IP nh IP a h ng(multicast), l p dch v IP, RSVP(Resource Reservation Protocol Giao thc h tr ti nguy n) v mng ringo.

Dch v mng ring o IP (VPN) - VPN thit l p c s h tng cho mngintranet v extranet, l cc mng IP m cc cng ty kinh doanh s thit l p trn c s ton b cu trc kinh doanh ca h. Dch v VPN l dch v mng Intranet vExtranet m cc mng c cung c p b i nh cung c p dch v n nhiu t chc

khch hng. MPLS k t h p v i giao thc cng bin (BGP) cho php mt nh cung c pmng h tr hng nghn VPN ca khch hng . Nh vy, mng MPLS cng v i BGPto ra cch thc cung c p dch vVPN trn cATM v cc thit b da trn gi tin r tlinh hot, dm r ng quy m v d qun l. Thm ch trn cc mng ca nh cungc p kh nh, khnng linh hot v dqun l ca cc dch vMPLS+BGP VPN luim chyu.

i u khi n l u l ng v nh tuy n IP r rng - vn quan tr ng trong cc

mng IP lin tc l thiu kh nng iu khin linh hot cc lung lu l ng IPs dng hiu qa di thng mng c sn. Do vy, thiu ht ny lin quann kh nnggi cc lung c chn xung cc ng c chn v d nh chn cc ngtrung k c bo m cho cc l p dch v ring. MPLS s dng cc ng chuynmch nhn (LSPs), chnh l mt dng ca lightweight VC m c th c thitl p trn c ATM v thit b da trn gi tin. Kh nng iu khin lu l ng IP caMPLS s dng thit l p c bit cc LSP iu khin mt cch linh hot cc lunglu l ng IP.



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1.4 Tm tt ch ng Nh vy, ch ng 1 Gi i thiu t ng quan v cng ngh chuy n mch nhn a

giao th c (MPLS) . Trong ch ng ny trnh by vkhi nim vMPLS, s ra i caMPLS da trn k t h p hon ho ccu im ca cng ngh IP, cng nghATM. Do cc nguyn l c bn ca cc cng ngh IP, ATM, MPLS cng c tm hiu. Ngoi ra, tnh hnh trin khai cng ngh v qu trnh chun ho vMPLS, cng nh ccu im vng dng chnh ca MPLS cng c c p n.



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Ch ng 2: cc thnh phn v hot ngca mng mpls

2.1 Cc khi nim c bn ca mng MPLSMt vi khi nim c bn cn phi hiu r tr c khi m t hot ng ca mng

MPLS.

a) L p chuy n ti p t ng d ng (Forward Equivalence Class - FEC)

L p chuyn ti p t ng ng-FEC l mt khi nim c dngch mt l pcc gi tin c u tin nh nhau trong qu trnh vn chuyn. Tt c cc gi trong mtnhm c i x nh nhau trn ng t i ch. Khc v i IP thng th ng, trongMPLS, cc gi tin ring bit c gn vo cc FEC ring ngay sau khi chng vomng. Cc FEC da trn yu cu dch v cho vic thit l p cc gi tin hay n gincho mt tin a ch.

b) Nhn v gn nhn

Nhn trong dng n gin nht xcnh ng i m gi c th truyn qua. Nhn c mang hay c ng gi trong tiu l p 2 cng v i gi tin. B nhtuyn kim tra cc gi qua ni dung nhnxc nh cc b c chuyn ti p k ti p.Khi gi tin c gn nhn, cc chng ng cn li ca gi tin thng qua mng ngtr c da trn chuyn mch nhn. Gi tr ca nhn ch c ngh a cc bngh a l chngch lin quann cc b c chuyn ti p gia cc LSR.

Nhn c gn vo gi tin khi gi tin c s p x p b i cc FEC m i hayFECang tn ti. Gi tr nhn ph thuc vo ph ng tin m gi tin c ng gi.i v i mng Frame Relay s dng gi tr nhn dng k t ni l p lin k t d liu -DLCI ( Data Link Connection Identifier), ATM s dng tr ng nhn dng ng o

trong t bo/ tr ng nhn dng knho trong t bo (Virtual Path Identifier/ VirtualCircuit Identifier - VPI/VCI). Sau gi c chuyn ti p da trn gi tr ca chng.

Vic gn nhn da trn nhng tiu ch sau:

nh tuyn unicastch K thut lu l ng Multicast Mng ringo (Virtual Private Networks - VPN) Cht l ng dch v (Quality of Service - QoS)



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nh dng chung ca nhn c gii thch trong hnh 1. Nhn c thhin rtrong tiuca cc l p lin k t (VPI/VCI ca ATM trong hnh 2 v DLCI ca FrameRelay trong hnh 3) hoc trong l p d liu shim (gia tiul p lin k t d liu l p 2

v tiul p mng l p 3 nh trong hnh 4)

Hnh 1 : nh d ng chung c u nhn MPLS

Trong hnh 1, phn SHIM MPLS:

Label (20 bit): cha ga tr nhn Exp.bits: CoS (3 bit)- cht l ng dch v

BS(1 bit) bie-stack: xcnh nhn cui cng trong ngn x p TTL (8bit)- time to live: tr ng nh th i

Hnh 2 : L p lin k t d liu l ATM



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Hnh 3 : L p lin k t d liu l Frame Relay

Hnh 4 : Nhn trong shim - gi a l p 2 v l p 3

c) T o nhn

To nhn da trn cc ph ng php sau: Topo: nh giao thc nh tuyn thng th ng (OSPF v BGP) Yu cu: iu khin lu l ng da trn yu cu Lu l ng: nhn gi tinphn phi v gn nhnd) Ng n x p nhn l mt t p h p c th t cc nhn gn theo gi truyn ti thng tin v

FEC m gi nm trong v v cc LSP t ng ng gi s i qua. Ngn x p nhn cho php MPLS h tr nh tuyn phn c p. Mi mc trong ngn x p nhn gn lin v i

mc phn c p no. iu ny to iu kin thun l i cho ch hot ng nghm trong MPLS.

e) Bng chuy n ti p chuy n ti p chuy n m ch nhn

L bng chuyn ti p nhn c cha thng tin v nhn vo, nhn ra, giao dinvo, giao din ra.

f) C s d li u nhn (Label Information Base - LIB )

C s d liu nhn (Label Information Base - LIB) l bng cha cc gi tr

nhn/ FEC c gn vo cng nh thng tin v ng gi d liu truyn ti mi LSR xcnh cch thc mt gi tin c chuyn ti p.

g) ng chuy n m ch nhn (Label Switched path - LSP)

Trong MPLS, vic truyn d liu thc hin theo cc ng chuyn mch nhn(Label Switched path - LSP). Cc ng chuyn mch nhn cha mt chui cc nhnti tt c cc nt dc theo tuyn t ngun t i ch. LSP c thit l p tr c khi truynd liu hoc trong khi xcnh lung d liu no. Cc nhn c phn phi bngvic s dng giao thc phn phi nhn (Label Distribution Protocol - LDP) hoc giao

thc ginh tr c ti nguyn (Resource Reservation Protocol - RSVP) trn cc giao



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thc nh tuyn ging nh giao thc cng bin (Border Gateway Protocol - BGP) vgiao thc nh tuyn m r ng theo ph ng thc u tin tuyn ng ngn nht (OpenShortest Path First - OSPF). Mi gi d liu c ng gi li v mang cc nhn trongsut th i gian di chuyn t ngun t i ch. Chuyn mch d liu tc cao hon tonc th thc hin da theo ph ng php ny, v cc nhn cdi c nh c chnvo phn u ca gi tin hoc tbo v c th c s dng b i phn cng chuynmch nhanh cc gi gia cc lin k t.

h) C c u bo hi u Yu cu nhn - S dng c cu ny, mt LSR yu cu mt nhn t dng

xung ln cn nn n c th lin k t n FEC xcnh. C cu ny c th c dngtruyn n cc LSR ti p theo chon LER lira.

p ng nhn - p ng mt yu cu nhn, LSR lung xung s gimt nhnn cc bkh i ng lung ln s dng c cu nh xnhn.

Hnh 5 : C c u bo hi u

2.2 Cc thnh phn c bn ca mng MPLSa) B nh tuy n bin nhn (Label Edge Router - LER)

L thit b hot ng ti bin ca mng truy nh p v mng MPLS. LER h tr

nhiu cng k t ni t nhng mng khc (nh Frame Relay, ATM v Ethernet) vchuyn ti p cc gi lu l ng ny t i mng MPLS sau khi thit l p ng chuynmch nhn LSP s dng giao thc bo hiu nhn ti li vo v phn b lu l ngquay tr li mng truy c p ti li ra. LER c vai tr r t quan tr ng trong vic gn vtch nhn khi lu l ng i vo hoc i ra trong mng MPLS.

b) B nh tuy n chuy n m ch nhn (Label Switching Router - LSR)

LSR l b nh tuyn tc cao trong mng li MPLS tham gia vo vic thit

l p ng chuyn mch nhn LSP s dng cc giao thc bo hiu nhn thch h p v



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chuyn mch lu l ng d liu tc cao da trn cc ng thit l p. LSR c th k t ni v i LER hay cc LSR khc

c) ATM LSR : S dng giao thc MPLS trong mng iu khin thit l p

knho ATM, chuyn ti p tbon nt ATM LSR ti p theo.d) ATM LSR bin : Nhn gi c nhn hoc khng c nhn phn vo cc tbo

ATM v gi cc t bon nt ATM LSR ti p theo. Nhn cc tbo ATM t ATMLSR cn k , ti to cc gi t cc tbo ATM v chuyn ti p gi c nhn hoc khngc nhn

2.3 Cc giao th c c bn ca MPLS

Kin trc MPLS khng bt buc mt ph ng thc bo hiu n no cho phn phi nhn. Cc giao thc nh tuyn ang tn ti, nh giao thc cng bin (BGP) cci tin mang thm thng tin nhn trong ni dung ca giao thc. Giao thc ginhsn ti nguyn RPVP cng c m r ngh tr traoi nhn. Nhmc trch k thut Internet IETF cng xcnh mt giao thc m i c bit n nh giao thcthc phn phi nhn LDPlm r h n vbo hiu v qun l khng gian nhn. S m r ng ca giao thc LDP c s cng c xcnh h tr nh tuyn lin vng(explicit router) da trn cc yu cu vQoS v CoS. Nhng m r ng ny cng c

p dng trong vic xcnh giao thc (CR)-LDPnh tuyn da trn rng buc.Cc giao thc h tr traoi nhn nh sau:

LDP - ch ra ccch IP vo trong cc bng. RSVP, CR-LDP - s dng cho k thut lu l ng v ginh tr c ti

nguyn. Protocol-independent multicast (PIM)- s dng ch ra nhn tr ng

thia h ng- multicast.

BGP - cc nhn bn ngoi2.3.1 Giao th c phn phi nhn LDP

LDP l mt giao thc m i cho phn phi thng tin lin k t nhnn cc LSR trong mng MPLS. N c s dng nh x cc FECn cc nhn to nn ccLSP. LDP session c thit l p gia cc LDP t ng ng trong mng MPLS(khng cn thit phi lin k ). cc LDP ngang hng traoi cc dng bn tin LDP sau:

Bn tin discovery- thng bo v duy tr s c mt ca mt LSR trongmng



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Bn tin session- thit l p, duy tr v xcnh cc session gia cc LDPngang hng.

Bn tin advertisement- to ra, thayi v xo nhn nh x n cc FEC

Bn tin notification -cung c p thng tin t vn (advisory) v thng tin li bo hiu

2.3.2 Giao th c CR-LDP

Giao thc phn phi nhnnh tuyn da trn rng buc CR-LDP (Constraint-Based Routing-LDP) c s dng iu khin c ng bc LDP. Giao thc ny l phn m r ng ca LDP cho qu trnhnh tuyn c ng bc ca LSP. Cng ging nh

LDp, n s dng cc phin TCP gia cc LSR ng c p gi cc bn tin phn phinhn.

2.3.3 Giao th c RSVP

RSVP l giao thc bo hiu ng vai tr quan tr ng trong mng MPLS, n cho php ccng dng thng bo vcc yu cu QoS v i mng v mng s png bngcc thng bo thnh cng hay tht bi.

RSVP s dng bn tin traoi ti nguynt tr c qua mng cho lung IP.

RSVP l giao thc ring mc IP. N s dng cc gi d liu IP hoc UDP phn bin ca mng thng tin gia cc LSR ng c p. N khngi hi duy tr phinTCP, nhng sau phin ny n phi x l mt mt cc bn tiniu khin.

2.3.4 Giao th c MPLS-BGP

MPLS m r ng chc nng cho BGPmang cc nhn trong giao thc cng bin BGP, MPLS-BGP cho php b nh tuyn chy BGP phn phi nhn t i cc b nh tuyn bin khc mt cch tr c ti p thng qua bn tin c p nht ca BGP. Ti p cn

nym bo cho qu trnh phn phi nhn v cc thng tinnh tuyn n nh v gim b t tiuca bn tiniu khin x l.

2.3.5 Kin trc h thng giao th c MPLS

Thnh phn MPLS li c thchia thnh cc phn sau: Giao thc nh tuyn l p mng (IP) Bin chuyn ti p l p mng Chuyn mch da trn nhn mng li chi tit v l c nhn



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Giao thc bo hiu cho phn phi nhn iu khin lu l ng Kh nng t ng thch v i cc loi chuyn ti p l p 2 khc nhau (ATM,

Frame Relay, PPP)Hnh 8 miu t cc giao thc c th s dng trong hot ng MPLS. Ph ng

thc nh tuyn c th l bt k mt trong cc giao thc ph bin. Ph thu vo mitr ng hot ng, cc giao thc nh tuyn c th l OSPF, BGP, hay PNNI ca ATM,v.v Ph ng thc LDP s dng giao thc iu khin truyn tin (TCP)qu trnhtruyn d liu iu khin t mt LSR n LSR khc trong sut mt phinm bo tincy. LDP s dng giao thc datagram ca ng i s dng (UDP) trong sut giaionhot ng discovery ca n. Trong tr ng h p ny, LSR cgng xcnh cc phn t ln cn vng th i bo hiu s c mt ca chng trong mng. iu ny c thchin thng qua mt traoi cc gi tin hello.

IP Fwd l ph ng thc chuyn tuyn l p IP tm ng ti p theo bng cchni a ch di nht trong bng ca chng. V i MPLS,iu ny c lm b i ccLER. MPLS Fwd l ph ng thc chuyn ti p k t ni mt nhn v i mt cng li racho cc gi tin. Cc l p v i miu t trong hnh h p v i ng ntt c th thc hin bng phn cng to nn hot ng nhanh v hiu qu.

Hnh 8 : H th ng giao th c MPLS



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2.4 Hot ng ca MPLSMPLS tch chc nng ca IP ra thnh hai phn ring bit: chc nng chuyn

gi tin v chc nng iu khin. Phn chc nng chuyn gi tin v i nhim v gi gitin gia cc b nh tuyn IP, s dng c ch honi nhn t ng t nh ca ATM.Trong MPLS nhn l mt thc th c di c nh v khng ph thuc vo l pmng. K thut honi nhn vbn cht l tm nhn ca mt gi tin trong mt bngcc nhnxcnh tuyn ca gi v nhn m i ca n. Vic ny n gin h n nhiuso v i vic x l gi tin theo kiu thng th ng, v do vy ci thin hiu nng cathit b. Cc b nh tuyn s dng k thut ny c gi l b nh tuyn chuynmch nhn LSR. Phn chc nng iu khin ca MPLS bao gm cc giao thc nhtuyn l p mng v i nhim v phn phi thng tinnh tuyn cho vic chuyn mch.MPLS c th hot ng v i cc giao thc nh tuyn khc nhau nh OSPF v BGP(Border Gateway Protocol). Do MPLS h tr iu khin lu l ng v cho php thitl p tuyn c nh nn vic m bo dch v ca cc tuyn l hon ton kh thi.y lmt tnh nng v t tr i ca MPLS so v i cc giao thc nh tuyn c in. Ngoi ra,MPLS cn c c ch nh tuyn li nhanh.

2.4.1 Chuyn mch nhn

Thit b chuyn mch nhni x v i gi tin (hay t bo) tu theo nhn gnvo c n nh cho gi. Cc thit b chuyn mch xcnh a im v lm cchno gi s c chuyn ti p n da trn c s d li u nhn LIB(Label

Information Base) ti mi thit b chuyn mch nhn.

Thng tin cn thit chuyn ti p gi c tng k t trongnhn , thng tinny bao gm a ch ch , quyn u tin, thnh vin VPN (Virtual path Identifier), l pQoS, v tuyn iu khin lu l ng. Trong MPLS, nhn c chiu di c nh, ch c ngh a cc bv c mng hay gi trong tiul p 2 cng v i gi tin.

Khc v i chuyn ti p IP thng th ng, gi tin c phn tch mt ln khiivo mng MPLSgn cho n mt nhn t ngng v i mt FEC. Trong ni bmngMPLS cc b chuyn mch s da trn cc LIB tro i nhn chuyn ti p gitinn bchuyn mch ti p theo, qu trnh ny khng phn tcha ch n IP na.



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2.4.2hnh ca mng MPLS

Hnh9 : hnh m ng MPLS.

Min MPLS l mt t p k ti p cc nt hot ng nh tuyn v chuyn ti pMPLS. Min MPLS c th chia thnh Li MPLS (MPLS Core) v Bin MPLS(MPLS Edge) nh hnh 9.

Khi mt gi tin IPi qua min MPLS, ni theo mt tuyn c xcnh ph thuc vo nhm chuyn ti p t ng ng FEC m n c n nh cho khii vomin. Tuyn ny gi l ng chuyn mch nhn LSP. LSP ch c tnh mt chiu,tc l cn hai LSP cho mt truyn thng song cng.

Cc nt c kh nng chy giao thc MPLS v chuyn ti p cc gi tin gc IP

c gi lB nh tuyn chuyn mch nhn (LSR Label Switching Router). LSR li vo(Ingress LSR) x l lu l ng i vo min MPLS; LSR chuyn tip (Triansit LSR) x l lu l ng bn trong min MPLS; LSR li ra (Ingress LSR) x l lu l ng r i khi min MPLS; LSR bin(Edge LSR) th ng c s dng nh l tn chung cho c LSR

li vo v LSR li ra. 2.4.3 Cc b c hot ng ca MPLSgi tin truyn qua mng MPLS, phi thc hin cc b c sau:1. To v phn phi nhn2. To bng cho mi b nh tuyn3. To ng chuyn mch nhn4. Gn nhn da trn tra cu bng5. Truyn gi tin Ngun gi cc d liu ca n t i ch. Trong min MPLS, khng phi tt c cc

lu l ng ngun cn thit truyn qua cng mt ng. Da trn ccc tnh lul ng, cc LSP khc nhau c th c to ra cho cc gi tin v i cc yu cu CoS khcnhau.



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Hnh 10 : T o LSP v chuy n ti p gi tin thng qua mi n MPLS

Trong hnh 10, LER1 l li v v LER4 l li ra.Bng 1 gii thch cc b c hot ng ca MPLS khi gi d liu truyn qua

min MPLS

Bng1: Cc ho t ng MPLS

Hot ng MPLS Miu t

To v phn phinhn

Tr c khi d liu bt u truyn, cc b nh tuyn quytnh to ra lin k t nhn t i cc FEC c thv to bng.

Trong LDP, cc b nh tuyn lung xung bt u phn phi nhn v gn nhn/FEC.

Thm vo, c tnh lin quann lu l ng v dungl ng MPLS c iu chnh thng qua s dng LDP.

Giao thc bo hiu nn dng giao thc vn chuyn c th t v m bo tin cy. LDP dng TCP.

To bng Khi ch p nhn cc lin k t nhn mi LSR to ra mc trong bng c s d liu nhn (LIB).

Ni dung ca bng s xc nh mi lin h gia nhn vFEC, nh x gia cng vo v bng nhn von cng ra v bng nhn ra.

Cc mc c c p nh p bt k khi vic gn nhn c iuchnh li.



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To ng chuynmch nhn

Nh hnh 10, cc LSP c to ra theo chiu ng c v i ccmc trong cc LIB.

Gn nhn /bng tracu

B nh tuyn u tin (LER1 trong hnh10) s dng bngLIBtm ng ti p theo yu cu nhn cho FEC c th.

Cc b nh tuyn ti p theo s dng bng tm ng iti p theo.

Khi gi tinn LSR li ra (LER4), nhn c loi b vgi c truyn t i ch.

Chuyn ti p gi tin Hnh 10 m t ng i ca gi tin khi n c truyn t ngun t i ch hay t LER1, LSR li von LER4, LSR lira.

Ln u tin ca yu cu nhn, cc gi tin khng c nhnti LER1. Trong mng IP, n s tma ch di nht tm cc b c ti p theo. LSR1 l b c ti p theo ca LER1.

LER1 skh i pht cc yu cu nhn t i LSR1.

Yu cu ny s c pht trn ton mng nh hnh 10. LDPsxcnh ng dn o m bo QoS, CoS.

Mi b nh tuyn trung gian LSR2 v LSR3 s nhn gitin gn nhn thayi nhn v truyn i.

Gi tinn LER4, loi b nhn v gi ra khi min hotng ca MPLS v phn pht t i ch. ng truyn gi tin c ch ra trong hnh 10.

Bng 2 l mt v d n gin vbng LIB.

Bng 2 : V d bng LIB

Cng vo Nhn cng vo Cng ra Nhn cng ra

1 3 3 6

2 9 1 7



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m bo vic t ng thch v i h thng mng ang tn ti.

Ti p tc trin khai cc ph ng thc truy nh p Internet tc cao pngnhu cu ng i s dngang tng ln r t nhanh ti mt skhu vc.

2.5.3 M hnh mng MPLS ti Vit Nam

Da vo cc nguyn tc trn m hnh mng NGN ca VNPT ti Vit Nam v icng nghchuyn mch MPLS nh hnh 12.

Hnh 12 : S tri n khai m ng NGN c a VNPT

Trong m hnh trn c: L p t 3 b nh tuyn chuyn mch li ( core switch router) M160 ca

JUNIPER v i thng l ng chuyn mch 160 Gbit/s t ti thnh phH Ni, HChMinh, Nng.

L p t cc b nh tuyn bin ERX1400 ti cc tnh thnh khc.

Bng thng k t ni gia cc b nh tuyn li l 155 Mbit/s.



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Ti cc tnh thnh s l p t cc Media Gateway (MG), BRAS, DSLAM.MG l giao din gia mng PSTN v NGN truyn ti lu l ng thoi ng di.BRAS v DSLAMs dng k t ni cc thu bao xDSL nh hnh 13.

Hnh 13 : C u hnh k t n i t i cc B u in t nh thnh2.6 Tm tt ch ng Nh vy ch ng 2 gi i thiu cc thnh ph n v ho t ng ca mng MPLS .

Ch ng ny c p n cc khi nim c bn ca mng MPLS nh l p chuyn ti pt ng ng, ng chuyn mch nhn v cc thnh phn c bn ca mng nh b nh tuyn bin nhn, b nh tuyn chuyn mch nhn,c bit, ch ng ny t ptrung nghin cu cc giao thc c bn v hot ng ca MPLS. H n na, cc trin

khaing dng cng nghMPLS ti Vit Nam cng c trnh by.



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Ch ng 3: Thit k mng ATM MPLS

Mt trong nhng bt ng chnh gia cc nh cung c p truyn thng v mngthhsau - NGN (Next Generation Network) l vai tr ca ATM v MPLS. Cc nhcung c p dch v truyn thng u t r t nhiu vo cng nghATM cho mt mngli a dch v v khng c nh rt ATM ra khi mng li trong t ng lai gn. Tuynhin cc nh cung c p NGN cho r ng ATM cn phi a ra khi mng li v s thiuhiu qu, c bit l khi lu l ng ng tr c bng n, v thiu khnng m r ng choccng dng IP trong mi tr ng mng ng tr c hon ton IP. Hchn ph ng n

trin khai MPLS. Tuy nhin, hin ti vn cha r rng liu MPLS cp ng chay khngi hi v cht l ng dch v - QoS m ATM khng nh v tr camnh. ATM chon gi vn l cng ngh duy nht c kim nghim v thnhcng trong vic tch h p d liu, thoi, v video trn cng mt mng. Hin ti th mtgii php k t h p an ton kh thi l chy c ATM v MPLS trn mng ng tr c.Trong t ng lai, mng ng tr c da trn MPLS l gii php c a chung h n. Nhiu nh cung c p truyn thng ln k hoch hoc ang xc tin th nghim mngMPLS. Nhng nh cung c p m i c thun l i l c th i tr c ti p vo mng MPLS.

3.1 Gi i thiuChuyn mch nhna giao thc (MPLS) m r ng kh nng ca cc b nh

tuyn IP v cc chuyn mch ATM trong mt vi ph ng php chnh:

MPLS tch h p hon toniu khin nh tuyn IP v i cc chuyn mchATM, iu ny cung c p nhng h tr t nhin cc dch v IP nh loi dch v IP vIP a h ng (multicast) trn chuyn mch cng nh cc b nh tuyn ATM.

MPLS cung c p cc h tr cho kh nng m r ng quy m v s dng linhhot cc dch vmng ringo IP trn b nh tuyn v chuyn mch.

MPLS cung c p cc h tr cho k thut lu l ng IP, l iu khinmm do cc lung lu l ng IP theo cc ngun ti nguyn trn mng.



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3.1.1.1 M hnh ch c nng mng NGN

Mng NGN theo tiu chun ca tchc Multi-switching Forum (MSF) c mhnh chc nng 4 l p, bao gm:

L png dng/dch v L p truy nh p L p truyn ti

L p iu khin

L png dng v dch v

Vic hnh thnh cc l p chc nng ca mng NGN s gip cho cc nh khaithc mng ciu kin s dng cc thit b mng ca cc nh cung c p v m r ngcc thit b tng l p m khng lmnh h ng n cc l p khc.

L p truyn ti

L p iu khin

L p truy nh p

POTS, ADSL, RF, ATM, IP,ISDN, mobile, Multimedia

a) L p ng d ng v d ch v cung c p ccng dng v dch v nh: dch v mng thng minh IN, tr tin tr c, bng thng gi tr gia tngL p ny lin k t v il p iu khin thng qua cc giao din m API, nh c th khai pht trin nhanhchng cc dch v trn mng.

b) L p i u khi n bao gm cc h thng iu khin, gim st k t ni cuc gigia cc thu bao thng quaiu khin cc thit b chuyn mch (MPLS) ca l ptruyn ti v cc thit b truy nh p ca l p truy nh p. L p ny c chc nng k t nicuc gi thu bao v i l p ng dng v dch v, ng th i c chc nng qun l, chmsc khch hng, tnh c c

c) L p truy n t i bao gm cc nt chuyn mch, cc b nh tuyn, cc thit b truyn dn c dung l ng l n thc hin chc nng chuyn mch, nh tuyn cc k tni d i s iu khin ca l p iu khin.



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d) L p truy nh p d ch v bao gm cc thit b truy nh p cung c p cc cng k tni v i thit b u cui thu bao qua h thng ngoi vi cpng, cp quang, v tuyn.Thit b u cui thu bao c th l myin thoi c nh,ding, cc thit b truy

nh p tch h p hoc myu cui mng CATV Cc thit b truy nh p cung c p ccloi cng truy nh p cho cc loi thu bao sau: POTS, VoIP, FR, ATM, X25, xDSL, dingCc thit b cng truy nh p ny thc hin cc chc nng chuyn i cc loilu l ng khc nhau thnh dng tn hiu gi d i s iu khin ca l p iu khin vl png dng v dch v.

Mng MPLS, hay ATM MPLS l mng li trong h thng mng NGN. Tronglun vn ny ch t p trung nghin cu thit k m hnh mng ATM MPLS ny.

3.1.2 Chuyn mch thv cc thut ng chuyn nghnh MPLS l phin bn c chun ho t xut chuyn mch thc ngun gc

tCisco. MPLS v chuyn mch thging nhau vnguyn l v gn ging cvhotng. Ti liu ny s dng cc thut ngMPLS nhiu h n cc thut ng chuyn mchth, nh th hin trong bng 1. Ngoi tr mt thut ng l giao thc phn b th(TDP) .TDP v giao thc phn b nhn MPLS gn ging nhau, nhng s dng ccnh dng bn tin khc nhau v mt vi th tc khc nhau.Tuy nhin thut ng TDPkhng c s dng trong ti liu do khng c yu cu: ti liu khngc p n s khc nhau gia hot ng ca TDP v LDP.

Trong bng 3 thut ng b nh tuyn bin nhn khng c s dng.iuny l do thut ng t ng ng LSP bin c s dng v c 2 thut ng khcnhau dng cho cng mt i t ng s dn n nhm ln. LSP bin l thut ng k thut chnh xc h n.

Mt vi thut ng khc c s dng nh:

ATM MPLS l mt kiu mng MPLS m hot ng v i b chuyn mchATM lm chuyn mch MPLS. C th h n, ATM MPLS l mt kiu mng caMPLS m mi nhn khc nhau trn ng truyn c i din b i mt VC khc.

MPLS da trn gi tin c p n mt kiu ca mng MPLS m hotng trong cc mng khng s dng MPLS ATM. C th h n, l mt kiu mngca MPLS m cc nhn c mang nh l tiub xung gn trn mi gi. MPLSda trn gi tin cng c bit n nh MPLS khng ATM, MPLS da trnkhung v MPLS da trn b nh tuyn. Thut ng MPLS da trn khung khng



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c s dng trong ti liu ny khi thut d ng nh c p n Frame Relay, nhngMPLS da trn gi tin khng nht thit dngn Frame Relay.

LSR da trn gi tin l thit b m thao tc v ton bgi tin h n cc t

bo. B nh tuyn hot ng da trn gi tin l LSR da trn gi tin. LSR bin ATMcng l mt dng ca LSR da trn gi tin.

Chuyn mch v mng ATM truyn thng khng s dng MPLS ATM.Mng ATM truyn thng c thh tr mng MPLS da trn gi tin truyn trong knho c nh (PVC). Chuyn mch ATM truyn thng c th h tr MPLS ATM trong ng o c nh mng vai tr nh trung k o. Trong bt k tr ng h p no,chuyn mch ATM truyn thng thc t khng thc hin chuyn mch nhna giao

thc chng ch n thun h tr xuyn qua ng hm n i gi tin MPLS cmang.

Bng 3 : Cc thu t ng t ng ng trong chuy n mch nhnOld Tag Switching Term MPLS TermTag Switching MPLS; Multiprotocol Label SwitchingTag Switch/ed Label Switch/edTag (short for Tag Switching) MPLSTag (thing applied to a packet) LabelTag Core Router-TCR Label Switch Router- LSRTag Distribution Protocol TDP Label Distribution Protocol - LDPTag Edge Router-TER Edge Label Switch Router-Edge LSRTag Switch Controller - TSC Label Switch Controller - LSCTag Switch/ing Router - TSR Label Switch Router - LSRTag VC - TVC Label VC - LVCATM -TSR ATM - LSR

TFIB LFIBTag Switched Path - TSP Label Switched Path - LSP

3.1.3 Cu trc chung ca mng MPLS

Cu trc thng th ng ca mng MPLS ca cc nh cung c p nh ISP cth hin trong hnh 14. Mng MPLS bao gm b nh tuyn chuyn mch nhn bin(LSR bin). Pha khch hng c ni t i nh cung c p mng MPLS. Hnh 14 thhink t ni gia 9 khch hng v 6 LSR bin, nhng th ng c t i vi tr m khch hng

trn mt LSR. Thit b tin tr c khch hng (CPE) hot ng thng th ng theo



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h ng IP. N th ng khng hot ng trong MPLS. Nu CPE hot ng trong MPLS,cc nh dch v ss dng n mt cchc l p. Ch r ng LSR bin l mt phn canh cung c p mng v n c iu khin b i nh cung c p. LSR bin l c vai tr

ch cht trong hot ng ca mng v khng c ch n CPE d i bt k tnhhung no. Nh cung c p c thxcnh v qun l cc b nh tuyn ti pha khchhng, nhng b nh tuyn s chy IP thng th ng v bn ngoi mng MPLS.

Hnh 14 : C u trc m ng MPLS thng th ng.

Ch r ng thc tskhch hng nhiu h n skhch hng trong hnh v trn.

3.1.4 MPLS v cc k t h p IP trn ATM khc

Trong mng ATM, MPLS cho php cc chuyn mch ATM tr c ti p h tr cc dch v IP, cung c p cc hiu qu cao nht so v i cc cch ti p cn khc. IPtruyn thng trn ATM k t ni cc b nh tuyn trn cc mcho c nh (PVC).agiao thc trn ATM (MPOA) v cc cch ti p cn khc mang lu l ng IP trnchuyn mch cc mch o (SVC). IP truyn thng trn ATM, MPOA v cc cch ti pcn khcu c cc bt l i ging nhau nh:

Kh h tr nhiu loi dch v IP trn mng. V dnh l p dch v IP khngth c h tr mt cch t nhin b i cc chuyn mch ATM, v phi c h tr bngcch dch chuyn n tt ccc khi nim cht l ng dch vForum ATM khc.



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Kh qun l ti nhng n i dch v IP c h tr . Hai mc nh tuyn phi c qun l: nh tuyn IP (v i OPSF hoc EIGRP hoc t ng t) v PNNIhoc nh tuyn t ng t trn ATM. MPOA yu cu qun l theo kiu truyn thng.Chuyn dch v nh cc l p dch v IP n cht l ng dch vATM cng yu cu s qun l.

Cc dch v IP c thkh km hiu qu trn cc mng ATM. V d nh IPa h ng (mluticast) trn cc mng ATM kh thc hin trn qui m l n do s t ngtc ca nh tuyn a h ng, qu trnh x l thnh vin trong nhma h ng v duytr ATM VC.

Gi i hn t l v / hoc nh h ng nghim tr ng gia nh tuyn IP(OSPF,) v mng ATM mng hot ng khngn nh. Nu h n 30 b nhtuyn OSPF c k t ni trong mng l i dyc trn cc PVC, IP truyn thngtrn ATM c th dn t i lung t ca s c p nh p ccnh tuyn IP v lmnhh ng t i mng con. MPOA khng an ton khi k t ni cc b nh tuyn n mi b nh tuyn khc, v ch dnh cho k t ni t host t i cc b nh tuyn hoc t hostn host.

Cc dch v IP i hi s c gng qun l cc mng con. V d, l p tMPOA yu cu PNNI, bo hiu SVC, ATM ARP,ATMARPserver, NHRP, v NHRPserver, cng thm AAL5,nh tuyn IP (OSPF, v.v) v ngn x p IPv4.

MPLS trn mng ATM khc phc c tt c cc bt l i trn.

3.1.5 Cc b c thit k mng MPLS

Qu trnh thit k mng MPLS lin quann cc b c sau, v cc b c

c miu t trong cc phn ti p theo. Cc b c ny khng nht thit cn thc hintheo th t sauy nhng tt c cn c m bo.

Chn kiu thit b Thit k ccim truy nh p dch v Thit k mng ng tr c Thit k nh tuyn IP

Kim tra kch th c mng MPLS c th c a ra.



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3.2 Chn thit b MPLS

3.2.1 Cc cu trc ca mng MPLS

Mng MPLS c b nh tuyn chuyn mch nhn bin (LSR) v LSR li niv i nhau nh trong hnh 14. Tuy nhin cc k t ni c th c l p t trn nhiukiu thit b khc nhau, k t h p v i thit b truy nh p trong nhiu cch khc nhau.iu ny c thhin trong hnh 15.

a. MPLS d a trn gi tin n gin

b. ATM MPLS v i LSR bin d a trn b nh tuy n

c. K t h p ATM v MPLS d a trn gi tin



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d. ATM MPLS v i b t p trung truy nh p

e. ATM MPLS v i thi t b bin ATM tch h p

f . ATM MPLS v i Backhaul v ng hm



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g. M ng ng tr c kp

Hnh 15 : Thi t b trong m ng MPLS

a) MPLS d a trn gi tin n gi n

Cu trc mng MPLS n gin nht c th hin trn hnh 15(a). Cu trcny p dng trong mng ch c b nh tuyn, iu ny c th ng dng h tr dchv VPN hoc iu khin lu l ng. Trong cu trc ny, pha khch hng c c k tni tr c ti p n LSR bin da trn b nh tuyn. Cc LSR bin c k t ni n cc

LSR khc,iu ny cng da trn nn tng b nh tuyn. Cc b nh tuyn k t niln nhau b i mi loi lin k t o: ni ti p, ethernet, gi tin qua SONET, v.vv gitin c gi i v i tiuMPLS trn cc lin k t . Cc b nh tuyn lin quanth ng l Cisco 7200, 7500, hoc cc b nh tuyn gigabit 1200-series. B nhtuyn min trung bnh (Cisco 3600 v 4700 series) c th c s dng trong ccngdng di thng th p.

Bin i trong dng cu trc ny l v tr m ATM PVC lin k t im - imgia cc b nh tuyn. iu ny c th c s dng trong sut qu trnh dchchuyn n ATM MPLS.

b) ATM MPLS v i LSR bin d a trn b nh tuy n

Cu trc mng ATM MPLS n gin nht c th hin trong hnh 15(b). Nh trong tr ng h p trn, pha khch hng c k t ni tr c ti p n LSR bin datrn b nh tuyn, th ng l b nh tuyn 7200 hoc 7500 series. LSR bin c k tni b i ng kin k t ATM n thit b li l ATM LSR. ATM LSR c th l



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PVC v SVC. Chuyn mch bin IP+ATM bao gm b t p trung truy nh p chungBPX 8680, MGX 8850 v 6400.

f) ATM MPLS s d ng chuy n m ch ATM truy n th ng

Mng MPLS c th s dng thit b ATM truyn thng. Tr ng h p nyth ng c lm nh mt b c chuyn i MPLS banu n mng ATMang tnti. Chuyn mch ATM truyn thng c th c s dng trong ba cch nh thhintrong hnh 15(f).

Backhaul khi thit b truy nh p l t xa n LSR bin. Thit b truy nh p c k t ni n LSR bin b i PVC chuyn mch thng qua mng ATM.

ng hm thng qua chuyn mch ATM gia LSR bin v LSR ATM.Trong tr ng h p ny, LSR bin khng cn l p t lin k LSR ATM, nhng c th c k t ni thng qua mng ATM.

nghm thng qua chuyn mch ATM gia cc LSR ATM. Trongtr ng h p ny, mng li s dng chuyn mch ATM kiu truyn thng cng nh chuyn mch ATM.

g) M ng ng tr ckp

Nh cung c p dch v c thmun gi li c s h tng mng ATMang tnti trong khi xy dng c s h tng mng MPLS m i (mng MPLS ATM hoc MPLSda trn gi tin) bn cnh c s h tng c. Thit b bin IP+ATM Cisco h tr ttvn ny cho php khch hng truy nh p n c dch v v mng MPLS cng nh mng ATM c thm ch ch cn dng mt ng truy nh p. Kiu mng ny c th hin trong hnh 15(g). Thit b truy nh p IP+ATM c th l nhng thit b c dngtrong hnh 15(e). Mng trong hnh 15(g) h tr cc chc nng v dch v ging nh mng trong hnh 15(e) nhng mng hnh 15(g)i hi nhiu thit b h n.

3.2.2 Chn thit b MPLS Cisco

a) Ch n thi t b bin MPLS ATM

C bn vn cn xem xt khi chn thit b bin MPLS ATM:

Ki u d ch v c yu c u IP +ATM nh PVCu cui n u cui vcc dch vSVC cng nh cc dch v IP, hoc ch IP.

Ki u ng dy truy c p S l ng ng dy truy c p



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Cc y u cu cho d phng v tin c y a ra cc gii php khi ccthit b gim t i mc ti thiu (warm standby) hoc hon ton chng li (hot standby)s ph v cc lung d liu trong tr ng h p phn mm hay phn cng b hng, hoc

cc thnh phn ring bit nh card cng c th b hot-swapp. Hot standby ngh a lkhng hoc hu nh khng (d i 1 giy) c s ginon ca cc lung d liu t ucui n u cui trong tr ng h p thit b hng, bng cch khng phi nh tuyn litr khi thit b hng.

Mc d phng cho thit b bin MPLS c th c phn loi nh sau:

o None - Thit b bin khng c tnh nng d phng. Mng phi da vo s nh tuyn li p ng tin cy. Pha khch hng phi l thu baoi (dual-

homed) t i 2 thit b truy nh p khc nhau m bo tnh tin cy ca thit b.o D phng b x l - Thit b bin c d phng i ca b x l v

backplane v i d phngm hoc nng (warm standby hay hot standby). Khi cardcng (sport card) khng c d phngi, mng vn phi da vonh tuyn li m bo tin cy. Pha khch hng vn phi l dual-homed m bo thit b ngtin cy trong tr ng h p card cng b hng, nhng khch hng c l thu baoi(dual-homed) t i hai card khc nhau trn cng mt thit b truy c p.

o D phng y - Thit b bin c b x l d phng v card cng. Phakhch hng s nhn dch v ng tin cy t thit b bin ngay c khi h l thu bao n(single-homed) .

Khuyn ngh cho cc thit b da trn cc yu cu trn c th hin trong bng 2. Trong t ng lai, Cisco d ng nh h tr MPLS trn hu nh hoc ton bcc b nh tuyn vng trung bnh (mid-range) v high-end, hu nh hoc tt c ccchuyn mch ATM, v hu nh hoc tt c cc sn phm truy nh p v i kh nng nhtuyn. B i vy, nhiu thit b bin MPLS s tr nn c hiu lc trong t ng lai. Chitit h n v tt c cc sn phm trn ti trang web http://www.cisco.com

Mt vi vn thit thc cn ghi nh khi kim tra sn phm c bit chonhng sn phm c s dng nhLSR bin ATM:

Khi xem xt s ng dy truy nh p c h tr , hym skhe cm card c s dng b i giao din MPLS ATM. V d nh b nh tuyn 7206 Cisco c 6khe cm card, v bnh th ng h tr 48 cng ethernet (hay 8 trn mi khe). Tuynhin, khi s dng b nh tuyn 7206 Cisco nh LSR bin ATM, t nht c mt khe



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phi c s dng cho giao din ATM. Nh vy, s cng ethernet thc t ca LSR ATM 7206 Cisco l 40 cng ethernet.

Mt vi LSR bin s dng khe cm cardcard thc hin chc nng LSR

bin, v cc khe ny cn phi a vom. V dnh b t p trung truy nh p ton b 6400 Cisco c 8 khe cm card, nhng khi hot ng nhLSR bin, t nht mt trongcc khe cm phi c s dng cho card bx l nh tuyn nt v khng c card ng dy.

Mt vi LSR bin c th gii quyt lu l ng ca lung MPLS m bini theo s card ang x l. V d nh, ti th i im ny card b nh tuyn nt(NRP) trong b t p rung truy nh p ton b 6400 Cisco c th x l 150Mb/s full-

duplex ca lu l ng bin MPLS.iu ny c ngh a l v i phn s 25 % hot ngthng th ng, Cisco 6400 v mt NRP c th qun l bn ng dy truy c p OC-3/STM-1;do vy Cisco 6400 v i 2 NRP c th qun l tm ng dy OC-3/STM-1.S khe cm c thc hin b i card b x l cng phi c m khi tnh ton s ng dy truy nh p h tr cho bt k cu hnh ring no.

Bng 4 : Chn thi t b bin m ng MPLS cho m ng MPLS ATM

Thit b Kiu dch

v ng dy truy nhp H tr

d phngCh gii

B nhtuyn3600

ch IP Skhngng b t nginh, modem, ni ti p, framerelay, ethernet 10Mb/s, BRI $PRI ISDN, chui E1/T1,ethernet nhanh, OC3/STM-1ATM, giao din m thanh vnhiu loi khc

Khng S l ng nh LVC c h tr trn cardATM sdnt i gi i hnkch th cmng MPLS.Khngkhuyn nghicho nh cungc p mngMPLS ATM

B nhtuyn4700

Ch IP S l ng t ngi nhcachui ni ti p/frame relay,ethernet 10Mb/s, BRI $ PRIISDN, chui E1/T1, ethernetnhanh, E3, T3, hoc OC3/STM-

Khng S l ng nh LVC c h tr trn cardATM sdnt i gi i hn



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6400 IP+ATM ATM t tc E3/T3nSTM-4, ethernet v ethernetnhanh

D phng bx lwarm-standby

MGX8230,8250 &MGX8250 v iPXM-1

IP+ATM L ng l n Frame relay56k/64k, Frame relay T1/E1,channelize, ATM v Frame relay tc cao h n , serial vchannelize

FullWarm-to-hotstandby

Card RPMhay RPM-PR c yu cu

IGX8400Series

IP+ATM L ng l n FR channelize/unchannelize, ATMti tc T1/E1, T3/E3, OC-3/STM-1, giao din Subratevnhng loi khc

FullWarm-to-HotStandby

H tr LSR bin c ngh cho IGX8400 v iURM, vnchuyn H2CY01. NPM-68 c yucu. Phnmm chuyn

mch TBDBPX8680

IP+ATM L ng l n Frame relay56k/64k, T1/E1ATM, Framerelay v channelize. ATM titc E3/T3n STM-4 vnhng loi khc

FullWarm-to-HotStandby

Card trung k BXM phi c s dng.Card BXMModel-DXhay EX c khuynngh mnhm. CardBCC phi lBCC3-64 hayhin i h n.Card BCC4 c khuynngh mnh.



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6400 16xT3/E3 /ATM-1, 8xOC 12/STM 4

64k C D phng b x k

warm-standbyIGX8400

240xT1/E1,180xT3/E3,120xOC3/STM

120k Khngtrongln thchin dutin

D phnghon ton

Tt cgiaodin MPLS phi trn cardUXM, NMP-64B c yucu

8540MSR

64xT1/E1v i IMA,64xT3/E3,64xOC3/STM-1,32xOC12/STM-4, 8xOc12/STM-16

256k C D phng b x lwarm-standby

BPX8650

144xT3/E3,96xOC3/STM-1, 24xOC12/STM-4

192k CY2001 D phnghon ton

Tt c ccgiao dinMPLS phitrn cardBXM, cardBXM model-DX hay EX c khuynngh mnhm. Card

BCC phi lBCC3-64 haym i h n.Card BCC4 c khuynngh mnh m



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3.2.3 IP+ATM

IP+ATM l sc mnh chnh ca chuyn mch ATM Cisco. IP+ATM cs dng miu t cc thit b Cisco m cc thit b h tr ng th i cc dch v

ATM truyn thng (PVCs, SVCs, SPVCs, PVPs, v.v) v truyn ti IP ti u s dng MPLS. Khi nim chuyn mch IP+ATM c ch ra trong hnh 16(a). Mtchuyn mch n bao gm hai chuyn mch ring logic v i nhau: mt b nh tuynchuyn mch nhn ATM MPLS ti u cho truyn ti IP v chuyn mch PVC/SVCATM truyn thng. Mi trung k c thh tr c hai PVC (hoc SVC, v.v) v VCnhn MPLS (LVCs).

Mc d chuyn mch IP+ATM gm hai chuyn mch ring logic v i nhau

nhng vmt vt l n ch c mt chuyn mch. Tuy nhin chuyn mch IP+ATMc hai (hoc nhiu h n) b phn mm iu khin ring. Mt trong cc b phn mm iu khin PVC, SVC,v.v v b phn mm khciu khin MPLS. Nhng b iu khin ny hot ng mt cchc l p cho php mt chuyn mch vt l n hotng nh hai (hoc nhiu h n) chuyn mch o. Trong cc chuyn mch nh BPX8650 v MGX 8850, b iu khin c l p ny c thc thi nh s dng giao diniu khin chuyn mch (SCI). SCI cho php hai (hoc nhiu h n) b iu khinringiu khin mt cchc l p chuyn mch n, nh ch ra trn hnh 16(b). Phnmm iu khin MPLS c xcnh vmt vt l trong b iu khin chuyn mchnhn (LSC). Trong BPX 8650, LSC l thit b tch t gi chuyn mch chnh. TrongMGX 8850, LSC s c da trn modun x l nh tuyn (RPM) trong chnh gichuyn mch. B iu khin SCI khc c th l phn mm hot ng trn cardiukhin chuyn mch. LS 1010 v 8540 MSR thc thi cc chc nng t ng t nh chcnng ca SCI s dng giao din phn mm bn trong.

cho php cc mt phng iu khin hot ng c l p, cch thc SCI trong

chuyn mch phi c p ngun ti nguynn mt phng iu khin khc (MPLS,PNNI, v.v) . Trong BPX 8650, ngun ti nguyn cho PVC c iu khin b inh tuyn t ng c dnh ring trong mt cch t ng t. Cc ngun ti nguyn c phn chia theo cch ny l:

Khng gian VPI/VCI trn trung k - Mi mt phng iu khin nhn mtvng VPIs dng.

Di thng - Mi mt phng iu khin c m bo mt di thng xc

nh v i mc ch iu khin n p k t ni (CAC). V i phn chia mm, c mt qu



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d. C hai ch c n ng trong ng d liu

e. MGX 8850 hay Cisco 6400

Hnh 16 : IP+ATM

Phn x l cu hnh cho cc chuyn mch IP+ATM l vic phn bcc ngunti nguyn nyn cc bn iu khin khc nhau.iu ny lin quann vic to s phn chia khc nhau ca cc ngun ti nguyn lin k t cho cc bn iu khin khcnhau, nh thhin trong hnh 16(c).

S d ng IP+ATM

IP+ATM c th c s dng a ra cc dch v MPLS, v cc dch v PVC,SVC, v.vtrn cng mt mng. iu ny c ngh a l tt c (hay nhiu) chuynmch trong mt mng hot ng nh LSR ATM v chuyn mch ATM truyn thng,nh th hin trong hnh 16(a). Cc dch v ATM truyn thng c th cng c s dng cng v i dch v MPLS. Hnh 16(d) cho bit vic s dng PVC lin k t nlung lu l ng IP thng th ng t pha khch hng thng qua LSR bin ATM. MtPVC c s dng trong kiu ny c gi l PVC truy nh p MPLS. Cc PVCkhc l PVC truyn thng nh phn ca dch v PVC t u cui n u cuitruyn thng. Lu l ng t bin LSR c th sau dn quay tr li thng qua chcnng LSR ATM trong cng mt chuyn mch h tr PVC truy nh p MPLS, hocthng qua cc chuyn mch khc c la chn. Trong tr ng h p ny, ng d liu



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u cui n u cui cho lu l ng IP ca khch hng c th bao gm c hai PVCtruy nh p MPLS v VC nhn MPLS.

Chuyn mch bin IP+ATM tch h p nh MGX 8850 hay Cisco 6400 h tr

chc nng LSR ATM cng nh cc chc nng chuyn mch truy nh p truyn thng vchuyn mch PVC. Thm vo, chc nng LSR bin cng c tch h p trong thit b. iu ny c thhin trong hnh 16(e). Trong MGX 8850, chc nngnh tuyn c h tr b i ph ng thc ca modun bx l nh tuyn (RPM) v modun bx l nh tuyn nt (NRP) c s dng trong Cisco 6400. Mi RPM hay NRP hotng nhLSR bin. Trong MGX 8850, mt trong nhng RPM shot ng ng th inhLSC v LSR bin.

3.3 Thit k mng MPLS Mc tiu ca vic thit k mt mng MPLS tr c khi tin t i l p t l cung

c p mt mng s hot ng chnh xc v smangn s h p l ti thiu p ngmc ch thc hin. Do bn cht khng lin k t ca cc lung lu l ng IP, cc khchhng khng th ch ra chnh xc mt thit b vn chuyn m hmun gi lung lul ng n. B i vy khng c kh nng thit k hon ho mt mng trong th i gianu.

Cc b c thit k banu c mt mng hot ng: Thit k ccim truy c p dch v Xcnh cc lin k t ng tr c trong mng Thit k nh tuyn IP Xcnh khng gian VC nhn MPLSCc b c thit k sau cng l tin hnh ti u mng thit k hot ng lin tc

:

Ci tin thit k khi mng hot ngCc b c ny c xem xt trong cc phn ti p theo.

3.3.1 Cu trc ccim truy cp dch v Thit k ccim hin din (PoP) cho mng MPLS ATM c thc hin b i:

La chn kiu ng dy truy c p v thit b cho mng nh tho lun trn

C p pht cc PoP m c xcnh r ng l n b i cc thnh ph Dn sca khu vc ng i s dng bao quanh mi vng c p pht.



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Mt vi thit k PoPin hnh c ch ra trong hnh 17.

a) LSR bin ATM n

N i thit b LSR bin n cho vic h tr s l ng v kiu ng dy truyc p trong mt im truy c p dch v th cu trc n gin c th hin trong hnh17(a) l. S l ng ng dy truy c p (th ng hng chc hay hng tr m) c avo trong LSR bin n c lin k t t i phn cn li ca mng ATM MPLS. S l ng v kiu ng dy c h tr b i LSR bin n c miu t trong bng 4.

b) Nhi u LSR bin v m t LSR ATM

Mt PoP c thyu cu nhiu h n mt LSR bin do s l ng l n cc ngdy truy nh p c h tr ti v tr . Hay cc kiu LSR bin khc nhau c th cyu cu do nhiu kiu ng truy c p khc nhau c h tr . Hnh 17(b) c mt vicc LSR bin trong PoP, n cng bao gm mt LSR ATM. Mt LSR ATM:

Chuyn mch cc b lu l ng lu thng gia cc bin LSR khc trongmt PoP

T p trung lu l ng lu thng t mt PoPn mt b cc ng link t ATM MPLS n. C th la chn l cc b ng lin k t n tt c cc LSR bin hay s dng mt LSR binmang lu l ng n cc LSR bin cn li.

Ci thin kh nng nh tuyn. Ch mt bgiao thc nh tuyn IP (vdOSPF) ngang hng c yu cu t mt LSR ATMn ccim khc trong mngMPLS. Khng c LSR ATM, cc giao thc nh tuyn IP ngang hng ring c yucu t tt c cc LSR bin.

Tu thuc vo cc yu cu v tin cy, cc c p ng lin k t d phng cth c s dng gia cc LSR bin v LSR ATM.



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h p trong tr ng h p c tho lun trong phn Cu trc cho cc mng MPLS. Mtv d ca kiu PoP ny s dng gi truy nh p MGX 8220, LSR bin Cisco 7200 hay7500, v Cisco BPX 8650. Tr ng h p ny c th hin trong hnh 17(c). Lu

l ng IP t cc b t p trung truy nh p c mang trong cc PVC ATMn cc LSR bin. Cc lu l ng IP ny c th c mang thng qua BPX 8650 t ng t hotng nhmt LSR ATM, nh l mt chuyn mch IP+ATM. LSR bin trong PoPnh vy c thc ba kiu cu hnh khc nhau:

Thng th ng, mt hoc nhiu LSR bin s c dnh cho vic lu thngcc lu l ng IP trn PVC cc bin. B nh tuyn mang nhn x trong hnh 4(c) ccu hnh kiu ny. B s th ng c t nht hai giao din ATM: mt cho truy nh pPVC (t b t p trung truy nh p) v mt cho lu l ng MPLS ATM. Tuy nhin, lachn v i dung l ng th p h n l s dng nhiu giao din con trn mt giao dinATM: nhiu thit b u cui PVC v mt giao din con MPLS ATM.

Mt LSR bin lu thng v i PVC truy c p c thcng c ng dy truyc p khch hng k t cui tr c ti p trn n. B nh tuyn nhn z trong hnh 17(c) ccu trc kiu ny.

Cng c th l cc LSR bin trong PoP khng cho lu thng tt c ccPVC, v ch c ng dy truy c p k t ni tr c ti p. B nh tuyn y c kiu cuhnh ny.

S l ng cc LSR bin yu cu da trn:

Tng scc ng dy truy c p

Ton b di thng ca cc ng dy truy c p tnh t mc s dng trung bnh. V d, tng di thng ca cc ng dy truy c p c th l v d nh 1 Gb/snhng sng i s dng c thkhng v t qu 500Mb/s.

Kh nng ca mt b nh tuyn 7500 v 7200 vn hnh chc nng binMPLS gn ging kh nng IP truyn thng s dng chuyn ti p gia tng Cisco (CEF ).V d b nh tuyn 7200 v i bx l NPE 200c thh tr gn 200 Mb/s lu l ng bin MPLS v i cc gi tin IP c kch th c thng th ng.

Bxung cho cc LSR bin, mt BPX 8650 cn mt b nh tuyn 7200-serieshot ng nh mt LSC. B nh tuyn nhn c trong hnh 17(c) hot ng nh mtLSC. B nh tuyn ny c khuyn ngh mnh dnh cho vic hot ng nhmt

LSC v cng khng c s dng cho lu l ng d liu chuyn ti p.



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3.3.2 Xcnh cc ng lin k t ca mng MPLS

Phn ny c xu h ng l phn h ng dn cc b c xcnh ng lin k ttrong mng MPLS nh nhng khng phi l cch tt nht to nn mng . Cc

nh cung c p khc nhau sc ph ng thc ca ring hcho vic thit k v vn hnhmng nhng tt c nhng nh cung c p s gn nh t ng t nhau v ph ng thcm c miu t trong bn phn h ng dn ny. Nhc li r ng thit k mng banukhng th to ra mt mng hon ho. Mt viiu gn ng c thc hin trong qutrnh ny m dn n mng hot ng, nhng iu gn ng khng nht thit phiti u. B c cui cng trong qu trnh h ng dn ny l ti u ha mng viu ny ac tho lun trong phn Thit k mng hot ng lin tc.

1. Thi t k cc i m truy c p d ch v bin v cch b tr c a cc i m B c u tin trong thit k mng MPLS s l chn c , kiu v cch b tr cc

im truy c p dch v theo nhng vn c miu t trn. Mt v d c ch ratrong hnh 18. V d ny l da trn mng Australia. Australia c chn cho v d ny b i v n nh to nn mng thc t ph h p. PoP bin c ch ra tronghnh 18(a) c chn da trn c l ng yu cu lin k t ca khch hng m c ch ra trong hnh 18(b). PoP LSR bin da trn BPX 8600 (bao gm mt vi gi MGX8800 v BPX 8650 cho k t h p) c s dng Sydney v Melbourne, nhng n i nyc c di thng lin lc v s l ng cc ng lin k t l n nht trong v d ny. MGX8800 c s dng Brisbane. Adelaide v Perth l cc trung tm nhh n m c th c png t ng xng b i cc PoP da trn b nh tuyn trong v dny.

2. Xc nh l u l ng t m i i m truy c p d ch v

Da trn tng s cc di thng ng dy truy nh p, xcnh tng lu l ngt cc khch hngn mi PoP c th c xcnh. Xcnh chu k -bn c th c s dng v d nh xcnh t l trong sut th i gian bn nht trong ngy.iuny m bo cc thng s thch h p. nh ging mc c th l tng cc dithng ng dy truy c p ti mi PoP nh trong hnh 18(b). Tuy nhin, th ng h p lkhi ly c l ng th p h n mt l ng no, v d 50% tng bng thng truy nh pnh ch ra trong hnh 18(c).

3. Xc nh ma tr n l u l ng

Vic x l chnh xc b c ny s thay i t mng nyn mng khc. Australia, v d hai trung tm kinh t chnh l Sydney v Melbourne v i Sydney l



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r ng h n khngng k . Trong mng MPLS l n cho lu l ng IP kinh doanh giacc tiu bang, mt x p x h p lu tin c th t ng ng l 50% lu l ng s nSydney, 40%n Melbourne, 5%n Brisbane v 2.5 %n Adelaide v Perth. Nh

cung c p dch v ang tn ti sc thxcnh cc gi tr lu l ng cho cng ca h.Da trn phn tr m phn b lu l ng xcnh v tng lu l ng PoP t b c 2,ma tr n lu l ng c th c xcnh. Ma tr n lu l ng cho v d ny l trong bng 6. Trong mng thng th ng, ma tr n ny gn nh i xng. V d trong bng6, lu l ng t Sydneyn Adelaide l 12.5Mb/s nhng lu l ng t AdelaidenSydney l 25Mb/s. Nu lu l ng i xng h n khong 2:1 hay 3:1 th c li trongvic xcnh lu l ng hay dng m hnh.

4. Xc nh cc lu ng l u l ng 2 chi u

Trong mng IP, lu l ng t x t i y s th ng chy dc theo cng mt ngv i lu l ng t y t i x (nhng theo chiu ng c li). Mc d cc lung ny c thb chng ln nhau do nhiu tnh nng giao thc nh tuyn, c th hu ch nu iu nyxy ra,c bit trong cc mng nh. Doiu ny, c ths dng cc lung lu l nghai h ng d h n cc lung mt h ng trong thit k mng banu. Xcnh cclung hai chiu cho mng mu c ch ra trong bng 7. Di thng lu l ng haichiu gia Adelaide v Sydney v d c ly 25 Mb/s l l n nht ca di thng mt

chiu t Sydneyn Adelaide (12.5 Mb/s) v di thng t Adelaiden Sydney(25Mb/s). To cc lung hai chiu theo cch ny s h ng t i xcnh lu l ngv t qu khngng k trong mng. iu ny hu ch khi b c x p x u tinthch h p.



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Hnh18 : V d thi t k mng phn b a hnh



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Bng 6 : V d mng - ma tr n l u l ng mt h ng

Bng 7 : V d mng L u l ng hai chi u g n ng

5. Thi t k cch b tr m ng ng tr c

Cch b tr ng tr c s lin quann nhng vn v:

B tr vnga l v dxcnh v tr tt cho cc nt

D phng mc mng v d c nhiu ng t i mi ch

D phng cc trung k

Cch b tr mng la chn trong v d ny c ch ra trong hnh 18(d). Cthc nhiu cch b tr khc nhau. Cch b tr m c la chn bao gm s k t h pmng vng ring lin k t cc nt lin k bn ngoi mng v mt mng hnh sao k t

ni cc nt tr vmt LSR ATM ph trong li mng. Cch la chn ny cung c p



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Hnh 19: V d thi t k mng Tnh ton b ng thng lin k t

8. i u ch nh m c d phng

Ti n i trung k d phng khng c s dng v mng da vonh tuynli p ng tin cy, th c th cn thit phi iu chnh bng thng lin k t m bo dung l ng chng li cc ng lin k t h hng . V d, nu nglin k t nhn r trong hnh 19(c) hng th cc ng lin k t s v t scn mangmt vi hay tt c lu l ng ca n. Ti cc ng lin k t ny c thsau v t quatc E3, vy mt ng lin k t STM-1 (hay nhiu ng E3) c th c yu cucho mi ng lin k t s v t. Tu ng t, nu lin k t u hng th lin k t v c th yu cu h n dung l ng E3. Cng vy, nu lin k t y hng th ti c yu cu cho



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lin k t w c thv t qu E3. B i vy, phn phi cc di thng lin k t cui cng c thhin trong hnh 19(d).

9. Ki m tra cc thi t b c l a ch n c ph h p khng

Vn ny lin quann vic kim tra trong bng 4 v bng 5 cc thit b PoP c la chn c th h tr s l ng v kch th c ca cc ng lin k t c lachn trong thit k mng. Mng trong tr ng h p ny c thv t qua cc b c kimtra nhng trong v d cho thy PoP Melbourne s dng MGX 8850 thay choBPX 8680. PoP ny cn hai hai ng lin k t STM-4 v hai ng lin k t STM-1khng h tr trn MGX 8850. Vy trong v dmang tnh gi thit ny, PoP cn thitk li v dbng cch s dng BPX 8680 thay v MGX 8850.

Lu r ng bt k thit k li nu c yu cu l mt vn t ng i nh. Nhiu kiu thit b Cisco khc nhau c th c s dng trong cc PoP MPLS ATMv n th ng c nhn thy r ng mt PoP c th xy dng p ng cc yu cuca mt v tr n gin bng cch s dng k t h p cc thit b c s dng ti cc v tr khc. Mt BPX 8680 v d k t h p v i vi gi (shelves) MGX 8850.

L u trn cc c p ng lin k t ATM d phng

C ba cch chnh hon thnh vic thayi cho mt c p ng lin k t

ATM d phng: Thayi mc lin k t d liu y l k thut d phng lin k t thng

th ng trong cc mng ATM truyn thng. Vic thayi xy ra do kim tra l p link t d liu v vt l trong chuyn mch ATM hay phn cng LSR ATM. Phn cngchuyn mch cng th ng thit l p bn sao ca tt c cc tr ng thi mch o trn link t d tr . Trong chuyn mch v i d phng mc lin k t d liu, bt c lin k t nsai hng s th ng dn n k t qu gn nh d liu mt bng khng trn bt k mch

o. Thm vo, nh tuyn v l p mng (IP hay PNNI, v.v) s khng b nhh ng b i vn hng ng lin k t, hoc ngay c c cnh bo r ng n va xyra. Tuy nhin v i d phng lin k t d liu, lin k t d tr khng c gi tr mangd liu ngoi tr tr ng h p lin k t chnh hng. Da vo cch n c l p t,chuyn mch bo v t ng (APS) c th l mt hnh thc d phng lin k t d liu.Trn MGX 8850 v BPX 8650, chuyn i APS SONET dn n khng thayi giaodin nh c nhn b i nh tuyn k t ni, v khng mt tr ng thi k t ni.



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H p knh o trn ATM (IMA)- IMA mang d liu trn mt nhm cc link t bng cch phn phi t bo qua cc lin k t trong kiu lun chuyn theo vng(round-robin) N cung c p c hai mc d liu phn chia qua lin k t v d phng.

Nu mt ng lin k t trong nhm hng, cc tbo khng c gi trn lin k t ,nhng cc lin k t khc vn s dng. IMA ch nn dng cho lin k t tc th p-nhm lin k t T1 hay E1.

Lin k t song song v i thay i l p mng trong tr ng h p ny c p trungk d phng c s dng vic bo v l p d liu khng c s dng tt c v tt c chuyn i k t ni din ra ti l p mng. nh tuyn IP hay PNNI cnh bo v i tt c lin k t hng v tcng li chng.iu ny khngc bit tt cho lu l ng h ngk t ni nhng lm vic tt v i nh tuyn IP v MPLS. V i OSPF nhiu ng tnhao nh nhau (equal-cost-multipath) hay t ng t, OSPF s chn lu l ng cn bngcho mi nh tuyn ngang qua lin k t trong mt c p lin k t. iu ny dn t i mtc p LVC nhn MPLS c thit l p cho mi ch trn mi lin k t. Nu mt trongcc lin k t hng,nh tuyn IP sphn pht lu l ngtrn cc lin k t cn li thitl p cc LVC. Nu h p nht VC c s dng, iu ny s khng yu cu bo hiuMPLS v c th hon thnh trong mt giy hayn nh vy. Tin b trong ph ngthc ny l n cho php di thng trong trung k d phng c s dng, cho php

lu l ng hiu qu tt nht c mang trong mng.Lin k t d phng c yu cu, cc khuyn ngh cho s dng cch thc ny

l nh sau:

Cc m ng IP+ATM - Mng IP+ATM ny c th s dng ghp knhov i d phng cho cc trung k tc th p v cch khc s dng d phng l p lin k td liu. iu ny trnhnh tuyn li nhiu ln ca lu l ngnh h ng k t ni

M ng MPLS ATM thu n tu Thm mt ln na mng ny nn s dngghp knho v i d phng cho cc trung k tc th p. Cch khc, nu mng s dng k t h p VC cc lin k t song song v i chuyn i l p mng c th c s dng to nn dung l ng mng y c gi tr s dng. Cui cng, nu k t h p VC lkhng th, d phng l p lin k t d liu nn c s dng.



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o Chuyn mch PVC v cc chc nng chuyn mch PVC l khng th thyv i nh tuyn IP. Nu pha khch hng c k t ni t i mt b nh tuyn b i mtPVC, th PVC l mt k t ni tr c ti p b c-1 t vin cnh nh tuyn IP. Xt v d

pha mang nhn a trong hnh 20(c) v xem nh y c k t ni b i PVCn LSR bin y. Khi, theo quanim nh tuyn, pha l lin k b nh tuyn y.

o B iu khin chuyn mch v chuyn mch cng nhau to nn ntnhtuyn ring.

S dng cc quy tc ny, quanim nh tuyn ca mng MPLS c th ctm thy. iu ny c thhin trong hnh 20(d).

Vic thit k nh tuyn IP trong mng MPLS theo gn ging nh qu trnh

thit k nh tuyn IP cho mng IP thng th ng. Bng cch xt theo quanim nhtuyn, mng c th c phn chia theo tng vng, s l c nh tuyn c th cthit k v v.v

V n nh tuy n IP c th trong m ng MPLS

Giao thc nh tuyn dng trong mng ng tr c MPLS c th l OSPFhay IS-IS. EIGRP c th cng c s dng nhng n s khng lm vic v i tnhnng k thut lu l ng IP da trn MPLS tin b gi l nh tuyn ginh tr c ti

nguyn (RRR). RRR yu cu giao thc trang thi lin k t nh OSPF hay IS-IS. KhiEIGRP l giao thc nh tuyn vec t khong cch, n s khng lm vic v i RRR.IGRP hay RIP cng hot ng v i MPLS nhng khng RRR v khng c khuynngh. Ch r ng RRR i khi c c p lng lo nh k thut lu l ng MPLS nhng thc t l mt kiu ring ca k thut lu l ng MPLS.

C th s dng lin k t IP khngnh s. iu ny gim s nhn dngch IP t i b nh tuyn v v th gim sLVC dng trong mng. Vn ny cng

c tho lun trong phn Xcnh khng gian VC nhn MPLS. Vic tng k t tuyn khng c lm LSR ATM. Nhiu vng OSPF hay

IS-IS c th c s dng trong mng MPLS ATM nh th hin trong hnh 21. MtLSR ATM c th c s dng nh b nh tuyn bin vng (ABR) OSPF hay IS-ISnhng ch khi vic tng k t l khng c xy dng ti cc b nh tuyn bin min.Trong hnh 21(c),iu ny c ngh a l a ch tr c c bit n trong tt c ccvng phi nh nhau. Mt ABR trong hnh 21(c) l khng th, v d tng k t khnngc th ln t i 1.1.1.0/24, 1.1.2.0/24 v 1.1.3.0/24 v i mt nh tuyn n cho



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1.1.0.0/16. Nu tng k t nh tuyn c yu cu trong mng MPLS ATM, n phi c lm ti LSR bin ATM, nh thhin trong hnh 21(b).

Quy tc trn cng p dng cho h thng t tr v BGP 4. Mt LSR ATM

c thkhng l b nh tuyn bin h thng t tr BGP nhng mt LSR bin ATM thc th.

nh tuyn ginh tr c ti nguyn (RRR) hot ng tt nht trong mng ng tr c m cha vng OSPF hay IS-IS n. Hin nay, RRR c th c s dngtrong mng nhiu vng n i m cc b nh tuyn bin vng l cc LSR ATM. Hnchny s c khc phc trong cc phin bn sau ca RRR.

Tng k t nh tuyn khng th c xy dng bn trong ca mng VPNMPLS. Bn trong ca mng MPLS h tr VPN c th c nhiu vng OSPF hay IS-ISnhng vic tng k t th khng th c s dng.

Nhng hn chvvic tng k t tn ti b i v vic tng k t dng mt vi kiuu ng chuyn mch nhn t khi thit k n k t cui. V d, cho r ng mt ABR tngk t ln t i 1.1.1.0/24, 1.1.2.0/24 v 1.1.3.0/24 v i nh tuyn n cho 1.1.0.0/16. Bygi xt gi tin IPa ch 1.1.1.23n v i nhn cho 1.1.0.0/16. ABR khng thchuynmch nhn gi tin. N phi nhn qua nhn v kho st cca ch IP tm gi tin c

th i t i 1.1.1.0/24. Khi cc LSR ATM khng thkho st cca ch IP, chng cthkhng lm tng k t nh tuyn IP.



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Hnh 21 : nh tuy n a vng v t ng k t trong m t mng MPLS

3.3.4 Xcnh khng gian VC nhn MPLS

Bn h ng dn thit k ny thhin nhiu vn trong thit k mng MPLSl t ng t trong thit k mng IP truyn thng. Mt ngoi lquan tr ng v s t ngt ny l cc yu cu LVC MPLS trn mi lin k t. Vn thit k ny c minhho trong hnh 22.hon thnh thit k mng MPLS ATM mt l ng cc VC phi c ginh tr c cho s dng nh cc LVC trn mi lin k t. y c th l mtvn , nh bt k chuyn mch ATM

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Thiet Ke Mo Hinh Mang ATM MPLS