Chuong 19 SONET SDH Nhom 6

8/2/2019 Chuong 19 SONET SDH Nhom 6

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Nhm 6:

Mai Thanh Minh 08108341

Nguyn Thanh Sn 08220511Nguyn Thanh Tun 08106231NguynThNhtL 08227521

TRNG I HC CNG NGHIP TP H CH MINHKHOA CNG NGH IN T

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NI DUNG

Phn 1: Mngtruyndn quang ngb SONETI. GiiThiu SONET

II. Cu trc tn hiungb

III. Add Drop Multiplexer

Phn 2: Mng phn cpsngb SDH

IV. Giithiu SDHV. Tc bit chunca SDH

VI. Giao din v cu trc khung ca SDH

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Phn 1

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19.2.1 Giithiu v bicnh

Cc tiu chun SONET c pht trinbi cc y banANSI T1X1 viphin bnu tinvo nm 1988. Tiu chunny quy nh cc tnh nng v chcnngcamththng giaothng vn ti da trn cc nguyn tc ca ghp knh ngb.

Trongbncht ny c ngha l nhnh tn hiu ring l cthc ghp trctip vo mt mctn hiu SONET cao hnm khng cn giai on ghp knh trung gian.

DS1 v E1 kh hnchkhnngqun l, kim sot vgim stmng. SONET (SDH) cung cp mt kh nng phongph trong xy dngqun l mng tin tin v khnngbo tr.Gn 5% SONET cu trc tn hiuc phnbhtrqun lv bo tr v vn hnh.

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SONET c kh nng vn chuyn tt c cc tnhiu nhnh cnhngha cho cc mngk thutstnti ngy nay. iu ny c ngharng SONET cthctrin khai trnmnghin c v thch hptng

khnng linh hot chomngbng cch vnchuyn ccloi tn hiuhin c.

Ngoi ra, SONET c s thch ng d dng cc

loi tn hiu dch v khch hng nh SMDS v ATM.Trn thc t, n c tibt k da trn nh dng nhphnchnghnnhTCP / IP, SNA, OSIch,X.25,frame relay, v cc nhdng LAN,cng gi

truyndn.

19.2.1 Giithiu v bicnh

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SONET da trn mt tn hiungb bao gm ccoctet 8-bit, c t chc thnh mt cu trc khung. Mtkhung gm N dng v M ct, trong 1 vung chamtoctet (1 byte). Cc gc trn_bn tri cha mt nhn dngmarkerninhnbit l chbtuca khung.

SONET bao gm mt cu trc cbn, cp u tincgi l STS-1. nhnghacacpu tin cng xc

nh ton bh thng phn cpca tn hiu SONETbi vtn hiu SONET cp cao hn thu cbng cch ghp knhngb cc m-un cp thp hn. Khi cp m-un dic ghp vi nhau, ktqu c k hiu l STS-N, N lmts nguyn.

19.2.2 Cu trc tn hiungb

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Kt qu nh dng sau c th cchuyni sang OC-NhocSTS-N tn hiuin. C mt mi quan h t l nguyn giacc m-uncbn tn hiuin STS-1 v

OC-N:

Vd,OC-NbngN tn hiuSTS-1. Chc OC-1, -3, -12, -24, -48, -192 c h trSONET ngy nay.

19.2.2 Cu trc tn hiungb

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Khung STS-1 l cc m-un cbn v l khixy dng ca SONET. y l mt trnh t ca810octets3 (6480 bit), trong bao gm cc octetsoverhead khc nhau v envelope capacity(dung lng

titrngca khung).

STS-1 c m tnhmt khung 90 ct, 9 hng,thi gian ca 1 khung l125 s (8000 frames per

second). STS-1 c tc bit 51,840 Mbps. Hnh 19.1. Trnh t truynca octet l hng quahng, t tri sangphi. Trong mi octet ca STS-1 bittrngs cao nht c truynu tin.

19.2.2.1 Khicu trc cbn

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Ba ct u tin gm ccTransport Overhead. C 27octet, trong 9 ci csdng lm Section Overhead v18 octet chaLine Overhead. Cn li 87 ct to nn dunglngcamng STS-1: Synchronous payload envelope(SPE)

l dung lngca frame STS-1. SPE STS-1 bao gm 783octet v c m t trong cu trc 87 ct, 9-hng.

Trong cu trc SPE, ct 1 c 9 octet l Path Overhead

ca STS (Poh). Ct 30 v 59 khng c dng payloadm c dng nhmtctfixed-stuffcnh chia SPEra tngphn gm 27 octet. 756 octet trong 84 ct cn licsdng cho titrngthctca frame STS-1.


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Hnh 19.3 Poh v dung lng STS-1 trng ti trong SPE STS-1.

Lu rng ti trng trong khung STS-1 ch c 84 ct.4/13/2012 12


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Cc octet trong cc ctfixed-stuff ny c gi trkhng xc nh.Cc gi trbtrcho cc ctfixed-stuffcami SPE trong STS-1 sto ra tnh chnl trongccb tnh ton con ngBIPcaSTS-1.

SPE STS-1 c thbt ubt c ni no trongdung lngcamng STS-1,btu trong frame STS-1nyv kt thctrong frame tip theo.

i khi SPE c th hon ton nm trong mtframe. STS payload pointer (F) thay i kch c trongtransport overhead. Nchnhv trca octet tip theoch SPEbtu. payload pointer F c m tnh sau.


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Hnh 19.4 STS-1 SPE thng nm trong khung STS-1


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Poh STS lin quan ti mi payload vcsdng trao i cc mu thng tinkhc

nhau tim phtnimnhn SPE STS-1.

Mt trong s cc mu thng tin trong Poh

lbo hiuv hiusuttruyndliu.


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Cc frame l s sp xp trnh t ca cc octet.

Khung STS-N c to thnh t cc octet STS-1 vSTS-M (M


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Concatenation lmini lin ktvi nhautheo kiuchui mc xch ca cc STS-1 trong mt STS-N, nch ra ni cha ni dung caphn k tip thng quapayload pointer nca STS.

Cu trc mtSTS-N gm Nx(87 ctv 9 hng). Bi vslin ktpacket, nn ta chcnthitlp 1STS Pohcho SPE ca STS-N.

Poh STS lun lun xuthinu tin trong N cc STS-1to nn STS-N.

Vi N=3 ta c:

19.2.2.3 STS Concatenation

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Hnh 19.7Cho thy s phn b transport overhead camt OC-3 mang theo mt SPEca STS-3c.


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Cc SONET SPE STS-1 dung lng 50,11 Mbps c

thitktbit chonhnh tn hiu DS3. Cu trc VT csdng cung cp trng tisub-STS-1 gingnh DS1.N bao gmbn kch c:

VT1.5 (1.728 Mbps) cho truynti DS1,

VT2 (2.304 Mbps) cho E1,

VT3 (3.456 Mbps) cho DS1C,

VT6 (6.912 Mbps) cho DS2.

Cc khi nim nhnh oc minh ha trong hnh 19.8.Bn VT ccu c thhin trong hnh 19.9. Trong cutrc 87 ct, 9-hng ca SPE STS-1, cc VT chim 3, 4, 6,hoc 12 ct,tngng.

19.2.2.4 Ccu nhnh o (VTs)

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C hai chhotng VT: floating mode vlocked mode. Floating mode c thit k gimthius trmngnmc ti thiu v cung cpktni hon chnh cho victruyn tn hiucp VT trongmngngb,bng cch cho php mi VT SPE float(ivi SPE STS-1) theo th t trnh slip bufferstimi VT qua cross-connect.

Nu dngVT1.5 cross-connected gia hthng truyn ti khc nhau m khng c s trmng,th floating mode cho php mt DS1 truyn ti mtcch hiuqu qua mng SONET.


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Locked mode tithiu ha sphctpca giaodin v h tr vn chuyn s lng ln ca tn hiuDS1 cho cc ngdngchuyni k thuts,bngcch kha cc SPE VT ring lcc v trcnhivi SPE STS-1,mi SPE VT1.5 s khng c cungcppayload pointer ring ca n.

thch ngvithi gian /vnngb hata phi b tr slip buffers ,do s c s tr mngkhinhtuyn cho VT1.5 thng qua mng SONET.


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19.2.2.5 Cc Pointer Payload

The Payload PointerSTS: cung cpmtphngphp cho php lin kt linh hot v nngngcc SPESTS trong cc gi STS, clpvi cc ni dung thctca SPE.SONET l mng ngb. N davo ngunxung camaster network clock.

Mngs thhmiphi cnhiuhnmtmasterclock.Vd ti Hoa Knhiu tnginh cc tngiaphng,mitngidu c master clock ca chnhn. Mimaster clockhotngclp,vc snnh

tt, nhng vn c th c mt sai s nh trong gia ccxung clock(1 1011 per month). Chcchns khng thng

b pha c. Do , SONETphiiuchnhkhonmtmc master clock hoc phn on vic cung cp xung

nhpcahthng phnphithi gian.4/13/2012 25


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Lc ny, ccchuynmchrivomcnnh xung clocknib cp thphn. Tnh trng ny cngphic qun l biSONET. Do ,Struyndnngbphi c khnnghotng hiu qu di nhng iu kin trn, v lc cc ntmnghotngmc xung clockrtging nhau.

thch ngvinhngsai s xungclock, SPE c thciuchnh theo hngpositive hoc negative trongmt octet mtthiimtruyntiframecth, bng cch tnh ton lihoccpnhtlipayload pointer mi nt mng SONET.

Sai s xung clock, cpnhtpayload pointer cngnhhngnsiuchnh pha ca xung nhpcihigia cc uvo tn hiu SONET v cc nt SONET. iu ny ni ln nghacadynamic alignment khi cc STS SPE c floattrong STSpacket.

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Payload pointerccha trong cc octet H1 vH2 trong LOH v chnhv trbtuca octet STSSPE. Hnh 19.10 Bit 1 n 4 lcdliumi,bit 5 v6 l khng xc nh.

Bit 7 n 16 l gi tr con trthct. y l mtsnh phn vi rng t 0 n 782. N ch ra imkt thc con tr v octet u tin ca STS SPE.

Mt gi tr con tr 0 ch ra rng STS SPEbtusau v tr octet H3, mtoffset ca 87 chobit STS SPE

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Phn tch con trtrngti chobitmt suy gimtn hiucbitnnhiuchnhtitrngpayloadadjustment jitter. Suy gim ny xut hin trn mtnhnh nhn tn hiu sau khi phc hi t mt SPE

phichunhng thay iPayload pointer. Hotngcathitb mng x l tn hiu nhnh cc lun pha dingay lptcbnhhng do squ mc jitter ny.

Nu thit k cn thn v s phn b xung nhpcho mnglingb,siuchnhPayload pointercthcgimthiunhnht, do lm gimmc

jitternhnh c thc tch ly qua truyntingb.

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19.2.2.6 Ba cp Overheadca SONET.

Path (Poh)Line (Loh)Section (SOH)

Cc mc overhead, biu din nh l onko di, c minhha trong hnh 19.11. Mt chcnngquan trng l h tr hotng v bo dng mng (OAM).

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Poh. h trv duy tr s vn chuyn ca SPE gia ccngdnucui, gm9 octet v chimctu tin ca SPEl ni SPE clp vo v tho ra. Mt trong s cc chcnngc th ca Poh:

Octet B3 BIP (bit-interleaved parity) tnh ton kim trachnlivittc cc bit ca SPE trc. Tr gi tnh tonc t trong Poh ca khung sau.

Octet G1Thng tin bo hiu v hiu sut truyn ti.Octet C2 Mt nhn ng truyn tn hiu cung cp cc

chi tit ca cu trc SPE. Rng 8 bit, xc nh 256 cu trc.Octet J1 trnh bi mt thng tin ch v s gn lin vi

ngdn,kim tra lin tcktningun_chca ng dntn hiu tibt k thitb tip nhn u cui dc theo ngtruyn,bng cch gim st chuithng tin.

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Octet F2 m t ng dy orderwire cho thng tin iukhin mng gia cc ng dn thit b.

LOH line overhead vSOHsection overhead htrv duy tr

svnchuynca SPE gia cc nt link. Hai nhm ny chias3 ctu tincakhung STS-1.SOHchim 3hng utin(gm 9 octet) v Loh chim 6 hng di cng (18 octet).

Cc chc nng ca LOH :Octet H1, H2, H3Payload pointer .

Octet K1 v K2 T ngbo v iu khin chuyn mch.Octet B2 BIP kim tra chn l.Octet D4 - D12 576 kbps knh d liu.Octet E2Thitlpng dy tc hnh Expressorderwire.

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Cc chcnngcaSOH:

Mu lin kt cc khung (octet A1, A2). Xc nh STS-1 (octet C1): mtsnh phn tng

ngvithtxuthin trong khung STS-N, m c thcsdng trong qu trnhng khung v cn lixc nh v tr ca cc tn hiu khc. BIP kim tra chn l (octet B1): gim st phn li. Thng tin lin lc knh dliu (octet D1, D2, D3). Thit lp ng truyn knh nib (octet E1). Knh ngisdng (octet F1).

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19.2.2.7The SPEAssembly/Disassembly Process

Payload mapping l qu trnh lp rp mt tn hiunhnh vo SPE. L hotngcbnca SONET.

Dung lng ti trngc cung cp cho mi nhnhtn hiu ring lthnglnhn khng nhiu so vi yu cuca cc nhnh tn hiu . Qu trnh mapping l ngbha cc nhnh tn hiu vi cng sut ti trng,bng cch

thmcc bit m vo dng bit.

Mt nhnh tn hiu DS3 tc danh ngha 44,736Mbps c ngb vi cng sut ti trng 49,54 Mbps

cung cpbimt SPE STS-1.4/13/2012 34


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Vicb sung POH hon tt qu trnh lp rp ca SPESTS-1 v tngtc bit ca tn hiuni ghp n 50,11 Mbps.Ti cc ucuihocimnhncuicamng, titrnggccaDS3 phi c phc hi Disassembly.

Qu trnh demapping v desynchronizes cc tn hiunhnh t tn hiukthp SPE bng cchb cc POH v cc bit

ph.Vd,mt SPE STS-1titrng nh x DS3 nvimttc tn hiuca 50,11 Mbps. Ktqu qu trnh stripping lmt tn

hiutn hiu DS3 khng lin tctc trung bnh l 44,74 Mbps. Cc gin on xung nhp c gim xungbng mt

desynchronizing phase-locked loop sau to ra mt tn hiuDS3lin tcyu cutctruynti trung bnh.

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19.2.2.8Line Rates forStandard SONET Interface Signals

Bng 19.1 cho thyTlngtruyn tiu chun cho OC-N vSTS-N.

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19.2.3 Add-Drop Multiplexer

SONET ADMghp nimthocnhiu tn hiuDS-N vo knh SONET OC-N. Mt ADM c thccu hnh cho chadd

drophocterminal.

Trong ch ADM, n c thhotngvi tnhiu tc thp DS1 ca cc thitb u cui trongmng SONET, nu chng c xung nhp ly t mt

ngun xung nhptngt nhau hoclytthitb phtxung ca (SONET) (tc l ngb). Nhng khngthly xung nhpthi gian t cc ngun khng ngb.

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Hnh 19.14 l mt v d ca mt ADM cuhnh chadddropvi giao din DS1v OC-N.

Mtgiao din SONET ADM vi hai tn hiu

full-duplex OC-N mt hoc nhiu tn hiu full-duplex DS1, c th cung cpmtgiao din tcthpty : DS1C, DS2, DS3, hoc OC-M (M N).

Thng tin trng ti nonpath-terminating ntmi tn hiuu vo OC-N, ca qua ADMSONET vctruyn giao din OC-N bn kia.

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19.2.3 Add-Drop Multiplexer Xung nhp cho truynti OC-N c ngungct:

(a) mt trong hai ngunngb ha bn ngoi,(b) mt tn hiun OC-N,

(c) mi tn hiun OC-N theomihng (through-timing),

(d) xung clock nida vo network application. Mi giao din DS1

cdliutmtng vo OC-N v chn dliu vo ng ra OC-N theo yu cu.

Hnh 19.14 cng cho thymt giao dinngb ha cho cctrnhng dng chuyn mch aphng vi xung nhp bn ngoi v hotng m-un giao din (OIM) cung cpkthutorderwire ccb, bochung nib, v cung cpmt giao din cho hotngcahthngiu hnh t xa. Biukhin l mtphncami SONET ADM, duytr v iukhin cc chcnng ADM, ktnivi giao dinkthutnibhoct xa v ktni n yu cu, hotngca cc tuyn ty cnthit cho phpbo tr,btr, v kim tra.

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Hnh 19.15 cho thy mt v d v mtADM trong ch terminal hotngvi giaodin DS1. Trong trnghp ny, ADM ghp n

Nx(28 DS1)7

lnhoc tngngvi tn hiuOC-N. Xung nhp cho cu hnh terminal clytmtngun xung ngb bn ngoi, hocl nhn t tn hiu OC-N, hoc da vo xungclocknica chnh n trn network application.

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Phn 2

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19.3.1 GiithiuSDH pht trin Chu u ( bi CCITT ), SONET

pht trin Bc M. S khc bit chnh l tc ngtruyn ban u. STS-1/OC-1 c tctruyn banu l 51,84 Mbps v SDH cp 1 c tc bit l155.520 Mbps. Cc t l ny l cc khi xy dng c

bn ca mi h thng. Tc truyn ca SONET STS-3/OC-3 tngtnh SDH STM-1 l 155,520 Mbps.Mt im khc bitna l trong tc ng

truyns. BcM, mng SONET tctruyn l DS1

hoc DS3. Mng SDH cc nc l 2,048 - 34 - 139Mbps (xem chng 6 ). iu ny c gii quyttrong mi trng SONET / SDH thng qua cc nvqunlSDH (AU) vitc 34 Mbps

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19.3.2 Tc bit chunH thng phn cp s ng b cp 1 l 155,525

MbpsHthng phn cpsngbcp cng cao thtc bit l bis nguyn cacpu tin.

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19.3.3 Giao din v cu trc

Hnh 19.16 minh hami quan hgia cc phnt ghp knh khc nhau ca SDH v cho thycc cutrc ghp knh chung.

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19.3.3 Giao din v cu trc

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19.3.3.1 Cc nhnghaSynchronous Transport Module (STM):

STM mt l cu trc thng tin c sdnghtrktnigia cc phn lp trong SDH. N tngtnhSTS trong mang SONET. STM bao gmtrngti thng tin

v section overhead (SOH) nhngtrng thng tin spxp

trong mt khi cu trc c lp li c mi 125 s. Ccthng tin ny thch hp cho truyn ti ni tip trn ccphng tin thng tin c lachnmt tcngb trn mng.

Mt SMT c bn ( SMT-1) c quy nh tc

155,520 Kbps. Nhng SMT bc cao hnc hnh thnh thc tctngngvi N lnbisca SMT cbn. Khnngca SMT khi N=4 v N=16 cnhngha v c gi trcao hnc xem xt bi ITU T. Mt STM bao gmmtnhm nvqun l(AUG) cng vi SOH. STM-N c cha NAUGs cng vi SOH.

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19.3.3.1 Cc nhngha

Container C- n ( n = 1 to n = 4 ):L nvnhnht trong khung truyndn,

phnt ny c kch thccha cc byte titrng thuc mt trong cc lung cn ng b

(PDH), lung hnh, lungsliu.

Virtual Container - n ( VC-n )( Container o):VC l mtcu trc thng tin csdng

h tr kt ni gia cc lp trong SDH. N chang thng tin trngti v tchc thng tin POHtrong 1 khiclplicmi 125s hoc 500s.

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19.3.3.1 Cc nhnghaVirtual Container - n ( VC-n )( Container o):

C 2 loi VC: Lower-Order Virtual Container-n, VC-n (n = 1, 2): VCcs.

Gmmt C-n (n = 1,2) n cng thm cc bytemang thng tin iukhin v gim st tuynni hai VC-n ny v gi l POH. Higher-Order Virtual Container-n, to VC-n (n = 3, 4):

VC-n bc cao hn.

Gmmt C-n (n = 3,4) n v tphp cc nhmkhi nhnh (TUG-2S) hocmttpca TU-3S cngvicc byte mang thng tin iukhin v gim st tuynni hai VC-n v cgi l POH.

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19.3.3.1 Cc nhnghaAdministrative Unit-n (AU-n): nvqun l

AU l mtcu trc thng tin cung cp s thchnggia cc lp cao v bphn ghp knh. N bao gmmt thng tin trng ti ( VC bc cao ) v AUP (

Administrative Unit Pointer).

AU-4 gm c VC-4 cngvi AUP, n ch ra s linkt pha ca VC-4vi khung SMT-N. AU-3 cnggm c

VC-3 cngvi AUP, n thhins lin kt pha ca VC-3vi khung SMT-N.

Trong mitrunghp AUP l cnh. Mthocnhiu AU cnhcnhngha trong mttrngtiSMT gi l mt nhm AU (AUG). Mt AUG gm cc AU-3 v AU-4 thngnhtvi nhau.

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19.3.3.1 Cc nhnghaTributary Unit-n ( TU-n ): khi nhnh

Gmmt VC cng thm mt con trkhi nhnh.Con trkhi nhnh chthsngb pha ca VC-n ivi POH ca VC mc cao hn tip theo. Con trkhi

nhnh cv tr cnh sovi POH mc cao hn.Container-n ( n = 1 4 ):Mt container l mtcu trc thng tin m hnh

thc l mtmngngb thng tin titrng cho 1 VC.

Vimi VC c 1 Container tngng. Khnngphihpc xc nh cho tcmng thng thng c1 sgiihn trong tiu chun Container.

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19.3.3.2 Cu trc khungCu trc khung cbnca SDH c m t

hnh 19.18.

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19.3.3.2 Cu trc khungKhung STM-1 gm 3 phn chnh: mo u, con tr

khiqun l AU v titrngca STM-1. Phn mo u:

Gm hng 1-3, 5-9 v 9xN ctivi STM mc N.

Con trkhiqun l AU: (nh con tr SONET)Cho php sp xpmt cch linh hot cc VC-n

trong khung AU-n. Do con tr c khnng thch ngvis thayi, khng ch trong cc giai onca VC-n

v SOH m cn trong cc tc khc nhau ca khunghnh.

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19.3.3.2 Cu trc khungCon tr AU-4 c cc byte ctrng l H1, H2

v H3 (H19.19).

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19.3.3.2 Cu trc khungBa con tr AU-3 khc nhau ccha trong tng

byte H1, H2, H3 (H19.20)

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19.3.3.2 Cu trc khung Frequencyjustification (s cn chnhtns) :

Nu c mt tn s offset gia tc khung caAUG v VC-n , th gi tr con trtnghocgim khi cnthit, i km bimthoc cc octets cn chnhdnghoc m tngng. Con tr lin tiphotngphi

cch nhau t nht ba khung hnh, trong gi tr con trl hngs.Nutc khung ca VC-n l qu chm ivi

AUG, th lin kt ca VC-n phi di li nh k trong

cng thi gian v gi tr con trphictng ln.Nutc khung VC-n l qu nhanh iviccAUG , th s lin ktca VC-nphic nng cao nhktrong cng thi gian v gi tr con tr sau phicgimi.

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19.3.3.2 Cu trc khungSau y tm tt cc quy tc (Ref.7) gii thch cc con tr AU-n:

1. Trong qu trnh hotng bnh thng, con tr xc nhv tr btu ca VC-n trong khung AU-n.2. Btks thay it gi tr con trhinticb qua tr khi mtgi trmi ph hpc nhnc ba ln lin tiphoc trcmt,xem quy tc 3,4 hoc5 (diy). Gi tr mi ph hpnhncba ln lin tip ghi (v d, c u tin hn) quy tc 3 v 4.3. Nuphnln cc I-bit cat con trcongc,mtshotng cn chnhdngcchnh. Gi tr con trtip theo sctng ln mt.4. Nuphnln cc D-bit cat con trcongc, mtshotng cn chnh m cchnh. Gi tr con trtip theo cgimi

mt.5. Nu NDF (cd liumi)c thit lp thnh 1001, th cc gi trcon tr trng s thay th ci hintich b libng gi tr con trminu khng ninhn l trong mt trng thi tngngvimt smt mt ca con tr.

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19.3.3.2 Cu trc khung nv qun l trong STM-N.

Trngti STM-N c thhtrN AUGs, miAUGc th bao gmmt AU-4 hoc ba AU-3s. VC-n kthpvimi AUG-n khng c mt giai oncnh vo khungSTM-N.V tr ca octet u tin trong VC-n cchnh

bi con tr AU-n . Con tr AU-n l mtv trcnhtrong khung STM-N.AU-4 c thc mang qua VC-4, mtsca TU-

ns (n=1,2,3) nhdngmtbdn knh 2 trng thi.

AU-3 c thc sdng mang qua VC-3 ,mtsca TU-ns (n-1,2) nhdngmtbdn knh 2trng thi.

Mt v d ca s sp xp nyc th hin

hnh 19.22 v 19.23b4/13/2012 60

19 3 3 2 C


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19.3.3.2 Cu trc khung

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19 3 3 2 C kh


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19.3.3.2 Cu trc khung

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19 3 3 3 S k i SMT 1


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19.3.3.3 Sktni SMT-1

Cc quy tcktni sau ycsdng

:1. Quy tcktni hai AUGs da trn hai loi khc nhauca nvqun l AU cth l AU-4 v AU-3, l sdngcu trc AU-4. V vy,AUG da trn AU-3 th c phn

knh mc TUG-2 hoc VC-3 theo loi ti trng v cdn knh li trong mt AUG thng qua cc tuyn TUG-3/VC-4/AU-4.

2. Quytcktni VC-11s vnchuyn thng qua cc loi

khc nhau can nhnh, cth l, TU-11 v TU-12, l sdngcu trc TU-11 VC-11, TU-11 v TU-12 c m ttrong ITU. _Rec.G709 (Ref.7).

Chuong 19 SONET SDH Nhom 6

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