Cac Phuong Thuc Tich Hop Ip 1 9805

7/31/2019 Cac Phuong Thuc Tich Hop Ip 1 9805

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N TT NGHIP B MN THNG TIN QUANG

TI:

CC PHNG THC TCH HP IP

TRN QUANG V NG DNG TRONG NGN

CA TNG CNG TY BU CHNH VIN THNG VIT

NAM

CHNG 1

TNG QUAN

Trong nhng nm cui th k 20 u th k 21, cng ngh truyn thng, tin

hc c nhng bc pht trin mnh m v c nhng nh hng su sc n

i sng kinh t x hi. S pht trin ny lm thay i hn cch sng v cch lm

vic ca con ngi v a loi ngi sang mt k nguyn mi - k nguyn ca

nn kinh t tri thc.

Khi cng ngh vin thng v tin hc pht trin n trnh cao, chng lun

lun tc ng v h tr cho nhau cng pht trin. Qu trnh ny dn n s hi t

ca cng ngh vin thng v tin hc, to nn mt mng truyn thng thng nht

p ng mi nhu cu dch v a dng, phong ph ca x hi. Mng vin thng

thng nht c xu th ton cu ho vi mc tiu pht trin:

- Cng ngh hin i.

- Cht lng tin tin.


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-Khai thc n gin, thun tin.

- Chun ho quc t v t c hiu qu kinh t cao.

Chnh v th, cn c mt phng thc truyn dn mi ra i c kh nng p

ng c cc yu cu ny.

1.1. Xu hng tch hp IP trn quang

1.1.1. S pht trin ca Internet

a) V mt lu lng

Thoi l hnh thc thng tin xut hin t lu v ngy nay lu lng thoi

ang i vo trng thi n nh m trong qu trnh pht trin kh c th c c s

t bin no. Trong khi , x hi loi ngi ang chuyn sang x hi thng tin,

nhu cu trao i s liu ln nn lu lng s liu ngy cng cao. S ra i v ph

bin ca mng Internet khin cho nhu cu trao i thng tin tng, dn n bng

n lu lng Internet. Theo s liu thng k trn th gii trong 5 nm qua, lu

lng Internet tng 86% mi nm, hn 6 ln tc pht trin ca lu lng

thoi. Hin nay, khong 45% dn s EU kt ni Internet. Cc nc Chu tuy t

l kt ni Internet hin cn thp, nhng trong mt vi nm ti s tng rt nhanh,

c bit l cc th trng tim nng nh Trung Quc v n .

Ngoi ra, ngy nay giao thc IP khng ch cn s dng truyn dn s liu

cho mng Internet m n cn c s dng truyn dn cc loi lu lng khc

nhau nh thoi, video... l cc dch v vi QoS cao. V vy, phng thc truyn

dn phi c dung lng ln v cht lng cao.

b) V mt cng ngh

Cc t chc vin thng quc t khuyn ngh nhiu cng ngh truyn dn

s liu khc nhau. S dng giao thc X.25 truyn dn c nhc im l thi


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gian tr ln do c nhiu th tc qun l, sa li, pht li gi tin v cn thit lp lin

kt trc khi truyn, cc lin kt ny c dng ring nn hiu sut s dng khng

cao. X.25 c thng lng ti a l 64 Kbps nn khng p ng c truyn thng

a phng tin.

khc phc, giao thc Frame Relay ra i cho php thng lng t ti 2

Mbps. ng thi n cn gim thi gian tr v khng c chc nng sa li, gi tin

hng s b loi b, vic kim tra gi tin c thc hin ti tng node trn ng

truyn v khi gi tin b hng s b loi b ngay v cc gi sau s c pht tip.

n ch, gi no thiu mi yu cu pht li.

IP bng hp s dng m ho vi sai nn vi cng mt tc truyn dn th

lng thng tin truyn i nhiu hn. Trong khi , IP bng rng ra i s cung cp

phng thc truyn dn c bng thng rng, truyn c tt c cc nhu cu dch

v ca x hi nh truyn hnh, hi ngh truyn hnh, giao dch in t, mua hng

ti nh, truy cp thng tin...

Cng ngh truyn dn IP c nhiu im u vit so vi chuyn mch knh

truyn thng, c th: n l hnh thc truyn dn thng tin theo cc gi nn nhtuyn cc gi tin l c lp nhau, hiu sut s dng ti nguyn mng cao, qun l

n gin, khai thc d dng... v n s l xu hng pht trin tt yu.

1.1.2. S pht trin ca cng ngh truyn dn

C nhiu hnh thc truyn dn tn hiu t u cui n u cui. Cc

phng thc truyn thng chnh l s dng cp. u tin l s dng cp ng. y

l hnh thc truyn dn n gin nht nhng li bc l nhiu nhc im nh:

bng thng hp, tc thp, chu nh hng ca sng in t...Hin nay, cp ng

ch cn c s dng truyn dn c ly ngn, dung lng t. ci thin cht

lng truyn dn, ngi ta s dng cp ng trc. Tuy cp ng trc hn ch


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c s nh hng ca sng in t nhng bng thng v tc truyn dn th

vn khng p ng c nhu cu pht trin. Cc h thng truyn dn v tuyn nh

vi ba s, v tinh cng ra i nhng cht lng ca cc phng php truyn dn

ny li ph thuc rt nhiu vo iu kin ca mi trng nh: nhit , ma, m... V th, cht lng ng truyn khng n nh.

Khi truyn dn cp si quang ra i em n mt phng php truyn dn

mi c bng thng rng, tc cao v cht lng truyn dn tt v t chu nh

hng ca sng in t cng nh cc iu kin ca mi trng xung quanh. Ngoi

ra, cc h thng ghp knh theo bc sng WDM cng ang c ng dng trn

mng, c kh nng p ng c tt c cc yu cu ca ngi s dng cng nhca cc nh cung cp. DWDM cn cho php ghp nhiu bc sng hn trn mt

si quang, nh vy gi thnh s gim trong khi dung lng ca h thng l rt ln,

p ng c s bng n thng tin ngy nay. DWDM l la chn tt yu cho cc

mng truyn dn.

1.1.3. N lc ca cc nh cung cp v cc t chc

Bn cnh nhu cu lp t cc modul nh tuyn IP, c mt s tham lun

trong lnh vc kinh t v k thut cp n nhng n lc nhm kt hp IP vi

cng ngh quang. V d, i vi cc nh cung cp dch v Internet (ISP) cn c

rng bng thng cho php ghp knh tng dung lng, v th c th s dng bin

php nh ghp knh theo bc sng mt cao DWDM p ng c cc yu

cu truyn ti lu lng ln mng. DWDM cho php ghp STM-16 (2,5 Gbps) hay

STM-64 (10 Gbps) knh thoi trn cc bc sng truyn dn song song trnmt si cp quang.

ISP cn dng cng ngh quang c chi ph thp truyn ton b cc gi IP

kch thc ln di dng quang trong sut qua cc im trung chuyn m khng

phi chuyn i li (khng cn chuyn tn hiu quang thnh tn hiu in, x l ti


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tng IP v chuyn i ngc li thnh tn hiu quang cho bc tip theo trn

tuyn). Cc nh cung cp lun mong mun thc y vic hon thin c cu k

thut lu lng IP nhanh chng xy dng cc chc nng cho tng quang nhm

p ng c yu cu tng s a ch d phng. Cng ngh truyn ti quang cn ck thut bo v v khi phc d liu mt cch nhanh chng. y l vn m cc

ISP rt quan tm khi h mun truyn c nhiu d liu c tnh khn cp cao.

Mt khc, mt s nh cung cp cho rng cc chc nng ca tng truyn dn

ng b ATM hay tng SDH - cc thnh phn chnh trong c s h tng ca nhiu

mng - s khng cn thit khi c cc chc nng tng t hay tt hn c thc

hin nh s lin kt ca tng IP v tng quang. Vic loi b mt tng tng ngvi vic loi b phn cng v chi ph vn hnh ca n; do , c s h tng ca

mng s c gi thnh thp v t phc tp hn. Tt nhin n khng ng cho mi

trng hp, c th l i vi cc nh cung cp cn s dng cc dch v ATM hay

TDM.

Cc hot ng gip cho vic thng nht cng ngh IP v cng ngh quang

thc hin tt hn vn cha c ni n nhiu t trc n nay. Loi router ccard ng dy cung cp OC-192/STM-64 c sn xut v s dng trong mt

s mng. Mt h thit b mng mi ra i gi l cc b nh tuyn theo bc

sng. Nhng thit b ny dng giao thc nh tuyn ng gi IP to v chuyn

mch mt s lng ln cc kt ni quang.

T chc IETF ang gii quyt mt s cng vic tm ra nhng cch tt hn

nhm thc hin truyn dn IP trn mng quang.ng ch hn, nhm lm vic vchuyn mch nhn a giao thc MPLS (MultiProtocol Label Switching) xut

vic m rng c th thc hin c ti cc kt ni cho quang OXC (Optical

Cross Connect) v c gi l chuyn mch bc sng a giao thc MPS

(MultiProtocol Lambda Switching).


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Hnh 1.1: Tin trnh pht trin ca tng mng.


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1. Giai on I: IP over ATM

y l giai on u tin trong cng ngh truyn ti IP trn quang. Trong giai

on ny, cc IP datagram trc khi a vo mng truyn ti quang (OTN) th phi

thc hin chia ct thnh cc t bo ATM c th i t ngun ti ch. Ti chuyn

mch ATM cui cng, cc IP datagram mi c khi phc li t cc t bo.

y l giai on u tin nn c y cc tng IP, ATM v SDH, do chi

ph cho lp t, vn hnh v bo dng l tn km nht. Tuy nhin, khi m cng

ngh ca cc router cn nhiu hn ch v mt tc , dung lng th vic x l

truyn dn IP trn quang thng qua ATM v SDH vn c li v mt kinh t.

2. Giai on II: IP over SDH

IP over SDH l giai on tip theo trong tin trnh pht trin hng ti mng

Internet quang m hnh ny c s dng trong nhiu mng thc t hin nay.

Trong hnh v ny, tng ATM b loi b v cc IP datagram c chuyn trc

tip xung tng SDH. Nh vy, loi b c cc chc nng, s hot ng v chi

ph bo dng cho ring mng ATM. iu ny c th thc hin c bi cng

ngh router c nhng u im vt tri so vi chuyn mch ATM v mt tnh

nng, dung lng v cn v router IP l phng tin c chc nng nh hng cho

n v truyn dn u vit: IP datagram.

Ngoi ra, vic c thm k thut MPLS b sung vo tng IP s xut hin hai

kh nng mi. u tin, n cho php thc hin k thut lu lng nh vo kh

nng thit lp knh o VC - ging nh cc ng c th trong mng ch gm cc

router IP. Th hai, MPLS tch ring mt iu khin ra khi mt nh hng nn

cho php giao thc iu khin IP qun l trng thi thit b m khng yu cu xc

nh r bin gii ca cc IP datagram (nh trong chuyn mch ATM i hi phi


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xc nh r bin gii ca tng t bo). Nh vy, c th d dng x l i vi cc IP

datagram c di thay i.

3. Giai on III: IP overOptical

Trong giai on ny, tng SDH cng b loi b v IP datagram c chuyn

trc tip xung tng quang. Vic loi b tng ATM v tng SDH ng ngha vi

vic c t phn t mng phi qun l hn. S kt hp IP phin bn mi vi kh

nng khi phc ca tng quang, cc thit b OAM&P v chc nng nh tuyn

phn b to ra kh nng phc hi, pht hin li v gim st nhanh. Mt im

mi l vi cu trc khung gn nh c th thay th cho cc chc nng m cc khung

SDH thc hin trong cc kt ni Och. S tn ti ca hng lot giao thc k thut

lu lng MPLS (MPLS TE) m rng kh nng hot ng cho mng quang v

tng IP, c bit l cc router IP ngy nay c th giao din trc tip vi mng

quang.

Thng qua 3 giai on pht trin trn ta thy rng cng cc giai on v sau

th cc tng ATM, SDH cng gim do t s dng v mt s hn ch vn c ca n

trong khi yu cu v cht lng dch v cng ngy cng tng, cn DWDM cng

tng ln do c nhng u im u vit cho vic tch hp cc gi tin IP trn quang.

Trong qu trnh xut hin mt s cng ngh mi h tr cho vic pht trin

truyn dn cho qu trnh tch hp IP trn quang nh GMPLS, DTM, GbE...Trong

phn tip theo s nghin cu m hnh phn lp ca chng.

1.2.2. M hnh phn lp ca cc giai on pht trin

Hnh 1.2 minh ho m hnh phn lp ca cc giai on pht trin.


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Hnh 1.2: M hnh phn lp ca cc giai on pht trin.

a) IP over ATM/SDH/Optical.b) IP over SDH/Optical.

c) IP over Optical.Tng OTN

Tng OTN l lp mng truyn ti quang, n bao gm cc lp sau:

Lp knh quang (Och): nh ngha mt kt ni quang (ng tia sng)gia hai thc th clientquang. Lp knh quang l s truyn dn trong sut cc tin

tc dch v t u cui n u cui (Knh quang Och tng ng vi mt bc

sng trong DWDM). N thc hin cc chc nng sau: nh tuyn tin tc ca thu

bao khch hng, phn phi bc sng, sp xp knh tn hiu quang mng kt

ni linh hot, x l cc thng tin ph ca knh tn hiu quang, o kim lp knh tn

hiu quang v thc hin chc nng qun l. Khi pht sinh s c, thng qua vic


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nh tuyn li hoc ct chuyn dch v cng tc sang tuyn bo v cho trc

thc hin u chuyn bo v v khi phc mng.

Lp on ghp knh quang (OMS): nh ngha vic kt ni v x l trongni b ghp knh hay mt nhm cc kt ni quang mc knh quang Och (OMS

cn c gi l mt nhm bc sng truyn trn cp si quang gia hai b ghp

knh DWDM). N m bo truyn dn tn hiu quang ghp knh nhiu bc sng

gia hai thit b truyn dn ghp knh bc sng ln cn, cung cp chc nng

mng cho tn hiu nhiu bc sng. OMS c cc tnh nng nh: cu hnh li on

ghp knh quang m bo mng nh tuyn nhiu bc sng linh hot, m bo

x l hon chnh tin tc phi hp caon ghp knh quang nhiu bc sng vthng tin ph ca on ghp knh quang, cung cp chc nng o kim v qun l

ca on ghp knh quang vn hnh v bo dng mng.

Lp on truyn dn quang (OTS): nh ngha cch truyn tn hiu quangtrn cc phng tin quang ng thi thc hin tnh nng o kim v iu khin

i vi b khuch i quang v b lp. Lp ny thc hin cc vn sau: cn bng

cng sut, iu khin tng ch ca EDFA, tch lu v b tn sc.

Lp si quang: l tng vt l di cng, gm cc si quang khc nhaunh: G.652, G.653, G.655... Cc si ny s c trnh by trong chng sau.

Tng SDH

Tng SDH c tc thp, cc mch ng dy TDM (v d lung 2 Mbps,

34 Mbps) ni vi cc thit b client(nh chuyn mch ATM), sp xp chng vo

khun dng ca cc khung ng b truyn ti qua mng truyn ti tc cao

(c th l STM-1). in hnh cho chc nng ny l hot ng ca b ghp knh

xen/r ADM SDH. Ni chung ADM c thit k s dng trong cu hnh mng

ring quang, v mng SDH c to bi hai hay nhiu mng ring kt ni vo nhau


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thng qua vic s dng cc thit b kt ni cho s DXC. Vic thit lp mt mch

TDM kt ni end-to-end c th mt nhiu thi gian bi v nh cung cp phi x l

ti tng ring v tng DXC dc trn ng truyn.

K tha mch ghp knh TDM trong mng thoi, mng SDH cung cp tt c

cc chc nng vn hnh, qun l, bo dng v gim st (OAM&P). Cc chc

nng ny c dng thit lp v qun l cc mch kt ni qua mng. bo v

thng tin khi si quang b t hay b cc tn hao quan trng khc, mng SDH c

chc nng chuyn mch bo v t ng (APS). APS cho php thit lp v chuyn

mch sang cc ng bo v vt l d phng trong trng hp li xy ra trn

ng hot ng. Dch v c khi phc nhanh chng (trong khong thi gianxp x 50 ms), nhng khi ta phi c bng thng rng hn v phi c chi ph

thm cho cc thit b c lp t trn ng truyn d phng.

Tng ATM

Tng ATM (nu c) nm ngay trn tng SDH, h tr mt vi chc nng

mnh cho mng. y l k thut kt ni c nh hng yu cu thit lp mt knh

o VC gia ngun v ch trc khi thng tin c trao i. VC c th c thitlp thng qua tin trnh x l ng mt cch t ng hoc bng lnh. Tin trnh

ny c s dng bo hiu ca ATM v cc giao thc nh tuyn. ATM c lp a

dch v cho php nh cung cp thc hin ghp knh v truyn ti lu lng d

liu, thoi v video vi tnh nng c th d on trc lu lng thc hin ghp

knh thng k ATDM. Ngoi vic nh ngha knh o VC trn mt ng truyn

xc nh gia hai im trn mng, nh cung cp cn c th s dng ATM thchin k thut lu lng TE.

Ti tng ATM c th thc hin chc nng chuyn mch gi theo tng t b o

ATM. Vicny c thc hin ti cc tng i ATM. Ti y, ch th knh o VCI


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Mt khc, nhc im ln nht ca IP chnh l tr ln do phi chia s ti

nguyn v cc gi tin phi x l tiu v c th phi phn tch datagram (nu

cn) ti mi node trung gian trn ng truyn dn.

khc phc c th ng dng rng ri phin bn mi ca IP l IPv6 c th

nh tuyn v phn on datagram ngay ti ngun. Ngoi ra, c th s dng cc

giao thc gip nh tuyn nhanh hn nh s dng giao thc MPS.

c th a k thut ny vo thc t, mt yu cu kh quan trng khc l

tnh hin hu ca cng ngh cng nh gi thnh thit b ca nh cung cp hay cc

thit b ca khch hng.

Nh vy, trong chng ny em trnh by xu hng tt yu l tch hp IP

trn quang. Trong , vi s pht trin mnh m ca Internet th giao thc IP v

cng ngh ghp knh theo bc sng WDM v DWDM l nhng cng ngh li v

ng mt vai tr quyt nh trong qu trnh tch hp IP trn quang. Trong phn

tip theo, em s nghin cu v giao thc v cng ngh ny. Tuy nhin, cc cng

ngh khc nh: MPLS, GMPLS, DTM, GbE lm tng tnh a dng cho qu

trnh ny v to iu kin thun li cho qu trnh tch hp IP trn quang s c

gii thiu trong cc kin trc c th tng ng.

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Cac Phuong Thuc Tich Hop Ip 1 9805