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CU 1: NU NH NGHA V TRNH BY CC C TNH CA ISDN

CCIT nh ngha ISDN l mng c pht trin t mng in thoi s(telephony IDN-Integrated Digital Network) cung cp kh nng kt ni hon

ton s ho gia cc u cui, phc v cho nhiu loi dch v (thoi v phithoi) t ngi s dng c th truy xut bi mt s gii hn cc giao tip amc ch c chun ha.

Cc chun cho mng ISDN c nh ngha bi t chc CCITT, ta s thyc mt s cc c tnh c bn c nu ra sau y:

1. Cung cp cc ng dng thoi (voice) v phi thoi (nonvoice) s dng mttp c gii hn cc tin ch c tiu chun ho.

2. Cung cp cc ng dng cho chuyn mch (switched) v khng chuynmch (non switched): ISDN s cung cp c k thut chuyn mch (circuitswitching) v chuyn mch gi (packet switching).

3. tin cy cao trn cc kt ni 64Kbps (ISDN bng hp).4. S thng minh ca mng: ISDN s thng minh trong mc ch cung cp

cc dch v c trng, bo hnh mng v cc chc nng qun l mng.5. C cu trc phn lp ca cc nghi thc: Cc nghi thc c pht trin

cho ngi s dng truy xut vo mng ISDN theo cu trc phn lp v cth nh x vo m hnh cho kt ni vi h thng m OSI.

6. Cu hnh a dng: Cho php pht trin mng ISDN khng ph thuc vochnh sch ca quc gia, vo cng ngh v k thut ang s dng cngnh cc thit b ang s dng ca khch hng.

CU 2: SO SNH U KHUYT IM CA CHUYN MCH KHNG GIANV CHUYN MCH THI GIAN

CU 3:TRNH BY BO HIU KNH CHUNG V KNH RING ? NUU,KHUYT IM CA BO HIU KNH CHUNG V KNH RING

CU 4: TRNH BY CU TRC TRUYN DN CA ISDN ?

Knh B: l knh ca ngi s dng dng truyn d liu s , ting ni m hos PCM, hoc l s kt hp ca nhiu thng tin c tc thp hn (d liu s,ting ni s ha) thnh tc 64 kbps. C 3 loi kt ni c th c thit lptrn knh B l :

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Chuyn mch mch: tng ng vi cc dch v chuyn mch s thngthng c s dng.

Chuyn gi: Bn thng xuyn:

Knh D: c dng cho hai mc ch: Ti cc thng tin bo hiu knh chung iu khin cc cuc gi chuyn

mch trn cc knh B tng ng ca giao tip. Knh D c th c dng cho chuyn mch gi hoc thng tin tc

thp cc thi im khng c thng tin bo hiu.Knh H: cung cp cho ngi dng thng tin vi tc cao ln hn 64 kpbs nhfasimile nhanh, s liu tc cao, audio tc cao, hi ngh t xa v video.

Tt c cc loi knh (B, D, v H) c nhm li thnh cc cu trc truyn dnv c chia thnh hai cu trc (H.4.1) l:

Cu trc knh c s (basic access) Cu trc knh chnh (primary access)

CU 5: TRNH BY CU TRC A CH CA ISDN ?

ISDN cng cn mt s nh s. S ny cn phi tha mn cc yu cusau:

Phi d hiu, d dng i vi cc thu bao. Phi tng thch vi cc thit b chuyn mch hin hnh. Phi d dng pht trin s lng thu bao.

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Phi d dng thng mch vi cc h thng mng s khc.Cu trc a ch ca ISDNCCITT phn bit gia s ISDN v a ch ISDN. S ISDN thit lp s lin quangia mng ISDN v s s ISDN. N cha y cc thng tin v h thng

nhm hng dn cuc gi theo mt l trnh no .Cc thnh phn a ch ny gm c: M vng: n nh vng ca ni n (hoc vng a l) trong cuc gi,

gm cc con s thp phn (t 1 n 3 con s), c n nh v gii thiutrong E.163.

M quc gia xc nh ni n: c chiu di thay i v l mt phn cas ISDN quc gia.

S thu bao ISDN: cng c chiu di thay i v l thnh phn ca sISDN quc gia. Thng thng s thu bao l s c quay gi ntrong mng cc b.

a ch ph ISDN: a ch ph di ti a 40 con s, cung cp thng tinthm v a ch. a ch ph khng c xem l mt phn ca s nhs nhng cng gp phn cu thnh mt phn bn cht ca a ch ISDN.

CU 6: TRNH BY CU TRC NGHI THC CA ISND ?

S pht trin cc chun cho ISDN lm thc y s pht trin cc nghi thctng tc gia ngi s dng trn mng ISDN v mng, cng nh tng tcgia cc ngi s dng ISDN vi nhau. C cc i hi ng nhin cho ISDNm khng nm trong cu trc thng thy ca OSI.

V d:

Nhiu nghi thc lin quan vi nhau: l vic dng nghi thc trn knh D thit lp, duy tr v kt thc mt kt ni trn knh B.

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Cc cuc gi a mi trng (Multimedia calls): ISDN cho php thit lp cucgi trong thng tin gm nhiu loi nh ting ni, d liu, fax v tn hiu iukhin

Nhiu im kt ni: ISDN cho php gi hi ngh.Tuy vy cng c nhiu nghin cu v quan h gia ISDN v OSI, t ara quan h gia cc nghi thc trong cc m hnh trn c biu din (H.5.1).

CU 7: TRNH BY NGHI THC LAP-D ?

Hai hot ng ny c th cng tn ti trn cng mt knh D.

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Tt c thng tin ca ngi s dng v cc thng ip nghi thc truyn dn didng l cc khung. Gm c cc trng (field) sau:

C hiu:

Mu bit 01111110 (7EH) l c nh du u v kt thc khung. Mu bit nyc dng b thu ng b khung.

a ch (Address): nhn dng thit b ngi s dng (v dch vu) ang gii.

TEI (Terminal Endpoint Identifier): nh danh im cui thit b u cui.

SAPI (Service Access Point Identifier): nh danh im truy xut dch v.

Mi thit b ngi s dng c cp mt TEI duy nht.

S kt hp gia TEI v SAPI cn c gi l nh danh kt ni tuyn d liu(data link connection identifier-DLCI).

iu khin (Control): dng xc nh loi khung c pht i. LAP-D xcnh 3 loi khung.

Cc khung thng tin (I): mang thng tin qun l hoc s liu t cc lp cao.

Trng ny cha s th t ca khung I v N (S) v s th t khung I mong chtip theo N (R). Dng nghi thc go-back N ARQ iu khin sai v lu lng.

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Cc khung nh s (U): iu khin trng thi ca tuyn lun l v cho phpchuyn s liu khng nh s.

Cc khung gim st (S): c dng cung cp nghi thc ARQ.

Trong trng iu khin cha bit P/F (Poll/Final) biu th mt s loi khungdng lm cc lnh (P c lp ln 1).

Thng tin (Information field): cha cc thng tin qun l hay d liu cangi s dng. Trng ny ch c mt khung I v vi khung U.

Dy kim tra khung(FCS-Frame check Sequence Field) l b m tch sai theochun a ra ca CRC-CCITT.

CU 8 : TRNH BY S KHI CA FACSIMILE NHM 4 ? NUU,KHUYT IM CA FACSIMILE NHM 4 ?

Nhm 4: cng l mt chun facsimile s trng en. Mc ch ca n ldng mng s tc 64 kbps v vi mt s chp nhn khng c li tdo. Phn gii ca nhm 4 l 200-400 phn t nh/inch. Nh nhm 3, kthut nn cng c dng gim s bit truyn. Vi nhm 4, thi giantruyn ch c vi giy so vi vi pht ca nhm trc.

H.6.8 l t chc ca mt h thng facsimile nhm 4. Cc phn t ch cht l:

B x l s b ban u (Preprocessor): nhn tn hiu t thit b qutanalog ri dng mt mc ngng chuyn thnh im trng hoc en.

Mch nn: Ma trn bit trnh by hnh nh c nn gim ch thathng tin.

Lu tr: h thng ngun v ch phi c b m nn d liu phhp vi h thng sa li trong mng data v cc giao tip c truyn u cui vi mng.

Giao tip truyn thng (Communication Interface): h thng nhm 4 cth giao tip n mt mng chuyn mch hoc chuyn mch gi, bao

gm ISDN. B gin: ni thu, lung d liu c gin li ti to nh nguyn

thy. B hu x l (Post-processor): ma trn bit gin c th x l thm

ci thin cht lng nh. V d khi phn gii ca my in ln hn thitb qut c th ni suy theo mt cch thc ci thin cht lng nh.

S cng ch ra vi ng dng thm vo ngoi n v qut v in ti liu nh: Th tn in t: nh mt bin i cho h thng th in t thng mi. Lu tr, khi phc t mt c s d liu nh: ti liu c th c lu tr

in ra t xa sau ny. Ti liu c th c to ra bng cch dng mt bx l ha.

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Chuyn i dng: T chun facsimile n dng khc. OCR/phn tch d liu ha: nh c th c truyn bng dng bit-map

cho cc b x l sau ny bng cch dng s nhn bit mu v cc kthut x l nh khc.

CU 9: TRNH BY CU TRC CHC NNG NGHI THC CA BO

HIU S 7 ?

Mng bo hiu knh chung thng c hai chc nng c bn: qun l cuc giv chc nng qun l mng.Cc phn t ca mng bo hiu: c 3 phn t chnh: im bo hiu (SP): l mt im bt k trong mng c kh nng iu

khin thng ip bo hiu. im truyn bo hiu (STP): l mt im bo hiu c kh nng to

tuyn cho mt thng ip. N c th l mt nt to tuyn thun ty hoc

cng c th bao gm cc chc nng v cc im cui (endpoint). Tuyn bo hiu: l tuyn d liu ni gia cc im bo hiu. Tuyn iu khin: (hay bo hiu) chu trch nhim thit lp v duy tr

cc cuc kt ni. Cc cuc kt ni ny c yu cu bi nh s dng quaknh D.

Tuyn thng tin: Sau khi thit lp kt ni, thng tin s c truyn itrn tuyn thng tin theo th thc end-to-end

Cu trc nghi thc Cng nh cc h thng m khc, SS7 c cu trc phn lp. Cu trc phn

lp SS7 gm 4 lp c bn (4 mc): 3 lp thp nht c xem l phn

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truyn thng ip (MTP). Phn ny cung cp cc dch v khng kt nic tin cy cho vic to l trnh cho cc thng ip ngang qua mng SS7.

CU 10: TRNH BY M HNH NGHI THC B-ISDN ?

Cu trc nghi thc B-ISDN v mt lun l c bn lp thng tin c lp nhau,da trn m hnh 7 lp OSI. Bn lp ca m hnh tham kho nghi thc B-ISDNc lin kt vi nhau qua ba mt phng: mt phng ngi s dng, mt

phng iu khin v mt phng qun l.Mt phng ngi s dng(user plane): thng tin chy qua tt c cc lp trongmt phng ngi s dng.

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Mt phng iu khin (control plane): c trch nhim thit lp, gii phng vgim st cc kt ni. ATM l c ch truyn dn nh hng kt ni.

Mt phng qun l (management plane): c chc nng qun l mt phng vqun l lp:

Qun l mt phng l lin kt cc chc nng v th tc ca mt phngqun l vi cc chc nng v th tc ca 2 mt phng cn li. Qun l lp gm c cc chc nng nh meta-signaling, v cc chc nng

OAM-meta-signaling l mt knh thng tin ring iu khin cc thtc bo hiu gia cc lp (ngha l bo hiu cho bo hiu). Thng tinOAM (Operation And Maintenance) c s dng gim st mng vqun l li ti lp ATM.

Lp vt lLp vt l gm 2 lp cao: mi trng vt l v lp con hi t truyn dn.

Lp con mi trng vt l: mi trng truyn dn vt l c th c hnhdung nh l cp ng trc, dy xon, hoc cp quang. Lp con hi t truyn dn: hi t truyn dn (TC) chu trch nhim gn

cc t bo ca lp ATM vo trong khung truyn dn ca mi trngtruyn dn ang s dng. Hai chc nng quan trng ca lp con hi ttruyn dn l phc ho t bo v to ra HEC (Header erro-control) l bm iu khin li ca phn mo u.

Lp ATMLp ATM c lp vi mi trng vt l. Sau y l cc chc nng chnh calp ATM: Ghp knh v phn knh cc t bo Bin i b nhn dng ng o (VPI) v b nhn dng knh o (VCI) To ra header ca t bo

Lp thch ng ATM (AAL) Lp con phn v ti hp on Lp con hi t

CU 11 : TRNH BY CU TRC HEADER CA ATM ?

ATM l mt th tc truyn dn da vo ghp knh phn chia thi gian btng b s dng cc gi d liu (t bo) c chiu di c nh. Cc gi d liuny c gi l cc t bo (cell) v c chiu di 53 byte. C 5 byte trong 53

byte ny c dng lm header ca t bo, gm c thng tin v a ch knh vng (cc nhn). Tt c cc nt trn mng c ni vi nhau qua mt hocnhiu chuyn mch ATM. Chuyn mch ATM c nhim v vn chuyn cc t

bo n cc ch khc nhau.

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Bi v chiu di ca t bo l c nh, nn c th vn chuyn nhiu t bocng lc. T bo ATM gm 2 phn: phn header (5 byte) v phn thng tin (48

byte). Header: ca mt t bo gm 4 bit dng iu khin lu lng, 20 bit

dnh cho cc nh danh ca ng v knh (VPI v VCI), 3 bit dng nh ngha loi thng tin v 1 bit dng cho u tin cho vic mt mtcc t bo, 8 bit dng cho m u khin li header.

Vng thng tin t bo gm 48 byte

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CU 12 : SO SNH ISDN BNG HP V ISDN BNG RNG ?

C TNH ISDN BNG HP ISDN BNGRNG

GINGNHAU

dch v DV:Voice + data Voice + data +audio + video

K thut chuyn

mch+ truyn dn

Digital KTchuyn mch

mch + KT chuyn mch gi

CMch gi ch

yu+ CM mch

Bo hiu SS #7(signal system SS #7

KHCNHAU

Mode truyn

STM ( truyn ng b) ATM (bt ng b)

Tc 64kbps = const Vi kbps vi chcGbps

Kch tht gi thay i C

nh=cell=53byte

Ngtc CMch CMach phn mm phn cng

heade (mo u) 1 byte vi chc byte 5 byte