CCAO NG KINH T K THUT TP.HCMKHOA IN T VIN THNG.o0o.. NG DNG CC CNG NGH MNG TH H MI DA TRN SOFTSWITCH

Gio vin hng dn: NGUYN NHT TIN Sinh vin thc hin : L PHC THNH NGUYN VN THIU

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I.Gii thiu3II.Ni dung chnh41 Gii thiu mng th h tip theo NGN v cng ngh chuyn mch mm(Softswitch)41.1S hnh thnh mng NGN41.2Cng ngh chuyn mch mm - Softswitch31.2.1Nhng hn ch ca tng i chuyn mch knh31.2.2Cng ngh chuyn mch mm theo quan im ca mt s nh pht trin91.2.3nh ngha chuyn mch mm (Softswitch)31.2.4Nhng li ch ca Softswitch i vi nh khai thc v s dng32ng dng ca cc cng ngh mng th h mi da trn softwitch32.1ng dng cho phng pht thay i iu khin softwitch trn tt c cc cell phone bi mt ngi qun tr32.2ng dng lm SS7, PRI Gateway ( gim ti Internet )32.3ng dng cho vic tm kim nh tuyn cho mng th h mi32.4ng dng cho phng php theo du cuc gi trn gateway trong mng th h mi32.5Trung k o - tng i chuyn mch gi chuyn tip32.6Tng i chuyn mch ni ht32.7Thoi trn bng thng rng3III.Kt lun3IV.Tham kho3

Vit ttTing AnhTing Vit

ADSLAsymmetric Digital Subscriber Lineng thu bao s khng i xng

AGAccess GatewayCng truy nhp

ASApplication ServerMy ch ng dng

AS-FAS-FunctionChc nng my ch ng dng

ATAccess TandemTng i truy nhp

ATMAsynchronous Transfer ModePhng thc truyn khng ng b

CDMACode Division Multiple Accessa truy cp phn chia theo m

CDRCall Detail RecordGhi m chi tit cuc gi

CSFCall Feature ServerX l iu khin cuc gi

DSLAMDSL Access MultiplexerTruy nhp ng dy thu bao s a thnh phn

DSPDigital Signal ProcessorsX l tn hiu s

FSFeature ServerMy ch c tnh

IADIntergrated Access DeviceThit b a truy nhp

ICNInternal Communcation NetworkMng thng tin ni b

IETFInternet Engineering Task ForceNhm k thut Internet

INIntelligent NetworkMng thng minh

IPInternet ProtocolGiao thc Internet

ISDNIntegrated Services Digital NetworkMng s a dch v tch hp

ISPInternet Service ProviderNh cung cp dch v internet

ITUInternational Telecommunications UnionHip hi vin thng quc t

IVRInteractive Voice ResponseTr li thoi tng tc

LANLocal Area NetworkMng cc b

LEOLow Earth OrbitV tinh qu o thp

M2UAMTP level 2 User AdaptaionTng thch vi ngi dng mc 2

MEOMedium Earth OrbitV tinh qu o trung bnh

MGMedia GatewayCng phng tin

MGCMedia Gateway ControllerThit b iu khin cng phng tin

MGC-FMGC- FunctionChc nng MGC

MGCPMedia Gateway Controller ProtocolGiao thc iu khin cng phng tin

MG-FMG-FunctionChc nng MG

MPLSMulti Protocol Lable SwitchChuyn mch nhn a giao thc

MSMedia ServerMy ch phng tin

NGNNext Generation NetworkMng th h sau

PMPacket Managern v qun l gi

PSTNPublic Switched Telephone NetworkMng thoi chuyn mch cng cng

QoSQuality of ServiceCht lng dch v

RANRadio Access NetworkMng truy nhp v tuyn

R-FRouting- FunctionChc nng nh tuyn

RLCRelease CompleteHon thnh gii phng cuc gi

RTCPReal Time Transport Control ProtocolGiao thc iu khin truyn ti thi gian thc

RTPReal Time Transport ProtocolGiao thc truyn ti thi gian thc

SCFService Control FunctionChc nng iu khin dch v

SCTPStream Control Transport ProtocolGiao thc truyn ti iu khin dng

SDHSynchronous Digital HeracheaPhn cp s ng b

SDPSession Discription ProtocolGiao thc m t phin

SGSignaling GaterwayCng tn hiu

SGCPSimple Gateway Control ProtocolGiao thc iu khin cng n gin

SGWSignalling GatewayGateway bo hiu

SIPSession Intiation ProtocolGiao thc khi to phin

SIP-TSession Intiation Protocol for TelephonyPhn m rng giao thc SIP dnh cho thoi

SS7Signalling System number 7H thng bo hiu s 7

SSFService Switching FunctionChc nng chuyn mch dch v

STPSignalling Transfer Pointim chuyn tip bo hiu

TCPTransfer Control ProtocolGiao thc iu khin truyn ti

TDMTime Division MultiplexGhp knh phn chia theo thi gian

VoIPVoice Over IPThoi qua giao thc internet

WDMWave Division MultiplexGhp knh phn chia theo bc sng

I. Gii thiu Ngy nay khi cng ngh ngy cng pht trin, v nhu cu ca con ngi ngy cng cao, th nhng i hi v dch v cng ch ln khc khe, i cng chng l nhng yu cu v s pht trin v hi t ca cc h thng vin thng v tin hc. Vi s pht trin nhanh chng v nhu cu ca ngi dng i vi nhng dch v a phng tin cht lng cao lm cho c s h tng thng tin v vin thng c nhng thay i ln v c bn. Xu hng vin thng da trn nn tng chuyn mch gi tc cao, dung lng ln v hi t c cc loi dch v trn cng mt h tng mng ang ngy cng pht trin mnh m v ch thnh mt nn tng tt yu ca s pht trin.

II.Ni dung chnh 1.Gii thiu mng th h tip theo NGN v cng ngh chuyn mch mm(Softswitch) 1.1.S hnh thnh mng NGNS gia tng c v s lng v cht lng ca cc nhu cu dch v ngy tr nn phc tp t pha khch hng kch thch s pht trin nhanh chng ca th trng cng ngh in t Tin hc Vin thng. Tuy nhin, cc cng ngh c bn lin quan n cc tng i chuyn mch knh hin nay pht trin qu chm so vi tc thay i v tc chp nhn lin quan n cng nghip my tnh. Chuyn mch knh l cc phn t c tin cy cao trong kin trc PSTN. Tuy nhin, chng khng bao gi l ti u i vi chuyn mch gi. Khi lu lng ca mng ngy cng tr nn phong ph v a dng th hin nhin phi c mt cng ngh, gii php mi cho thit k chuyn mch ca mng tng lai, l xt v mt k thut. Cn khi xem xt kha cnh kinh doanh thu li nhun th :Th nht: do cc nh khai thc dch v cnh tranh v cc nh khai thc cp trn cng ph thuc vo mt tp hu hn cc sn phm tng i in thoi ni ht, chnh iu buc h phi cung cp cc dch v ging nhau. V khi cung cp cc dch v ging nhau th ch c mt con ng duy nht thu ht khch hng l chnh sch gi c, mun c mt lng khch hng ln th phi gim gi cc. Nhng ch to s chnh lch v mt gi c vn khng phi l mt chin lc kinh doanh lu di tt trong lnh vc vin thng. Nu c gii php no m cho php to ra cc dch v tht s mi v hp dn th cc nh khai thc s c c hi to s khc bit v mt dch v ch khng ch v gi cc. Th hai : khi xt v kha cnh u t, th i vi bt k mt nh u t no, trc khi c nh u t vo vic xy dng mng, th yu t quan trng u tin mang tnh quyt nh l thi gian u t v hon vn, m ng lc ca n l t l gia s i mi v kt qu d bo v kinh t ca cng ngh li c chn trong mng. Do thi gian pht trin nhanh v chi ph vn hnh cng nh bo dng cc mng chuyn mch gi thp hn nhiu so vi chuyn mch knh, nn cc nh iu hnh mng ngy nay tp trung ch n cng ngh chuyn mch gi IP. Do vy, khi cng ngy cng nhiu lu lng d liu chy vo mng qua Internet, th cn phi c mt gii php mi, t trng tm vo d liu, cho vic thit k chuyn mch ca tng lai da trn cng ngh gi chuyn ti chung c thoi v d liu. Nh mt s la chn, cc nh cung cp dch v v ang c gng hng ti vic xy dng mt mng th h mi Next Generation Network - NGN trn hi t cc dch v thoi, s liu, a phng tin trn mt mng duy nht - s dng cng ngh chuyn mch gi trn mng xng sng (Backbone Network). y l mng ca cc ng dng mi v cc kh nng mang li li nhun m ch i hi gi thnh thp. V khng ch l mng phc v thng tin thoi, cng khng ch l mng phc v tryn s liu m l mt mng thng nht, mng hi t em li ngy cng nhiu cc dch v tin tin p ng nhu cu ngy mt tng, v kht khe hn t pha khch hng. Mng th h mi NGN khng phi l mt cuc cch mng v mt cng ngh m n l mt bc pht trin, mt xu hng tt yu. H tng c s mng ca th k 20 khng th c thay th trong mt sm mt chiu, v th NGN phi tng thch tt vi mi trng mng sn c v phi kt ni hiu qu vi mng PSTN. Nhng vn m mng th h mi cn gii quyt gm : Vn bo hiu v iu khin trn nhiu loi giao thc khc nhau cho hi t thng tin thoi, fax, s liu, a phng tin. Vn kt ni vi mng chuyn mch knh hin hu, c bit l kt ni phn bo hiu (mng SS7). Vn pht trin dch v Gii php ct li trong mng NGN chnh l cng ngh Softswitch- cng ngh chuyn mch mm. 1.2.Cng ngh chuyn mch mm - Softswitch 1.2.1. Nhng hn ch ca tng i chuyn mch knhHin nay c s h tng chuyn mch vin thng cng cng bao gm rt nhiu mng, cng ngh v cc h thng khc nhau, trong h thng chuyn mch knh s dng cng ngh ghp knh phn chia theo thi gian (TDM-Time Division Multiplex) pht trin kh ton din v dung lng, cht lng v quy m mng li. Mng PSTN ngy nay ni chung p ng c rt tt nhu cu dch v thoi ca khch hng. Tuy nhin trong lnh vc cung cp dch v thoi cn c nhiu vn cha c gii quyt mt cc thc s tho ng, cha ni n nhng dch v mi khc. Trong mng chuyn mch knh ngy nay, ch c cc khch hng c va v ln c hng li t s cnh tranh trong th trng dch v vin thng, h c th thu mt s lung E1 p ng nhu cu ca mnh. Cc khch hng doanh nghip nh, c 16 line tr xung c hng rt t u i. Trong khi th trng cc khch hng nh mang li li nhun kh ln cho cc nh khai thc dch v. Cc nh khai thc vn thu c rt nhiu t cc cuc gi ni ht thi gian ngn, t cc cuc gi ng di, v t cc dch v tu chn khc nh Voicemail. Hin nay, tt c cc dch v thoi ni ht u c cung cp thng qua cc tng i ni ht theo cng ngh chuyn mch knh, n gin bi v chng c gii php no khc. Chnh iu ny l cn tr i vi s pht trin ca dch v, bi nhng nguyn nhn chnh sau y: Gi thnh chuyn mch ca tng i ni htHu ht th phn thit b chuyn mch ni ht do mt s nh sn xut ln kim sot. Cc tng i ni ht ca cc nh sn xut ny c thit k phc v hng chc ngn, thm ch hng trm ngn thu bao. Vn t ra y l chng khng thch hp khi c s dng cho vi trm cho n vi ngn thu bao, bi v gi thnh thit b cao. Gi thp nht ca mt tng i ni ht thng khong vi triu USD, con s c th lm nn lng cc nh cung cp dch v, buc h ch dm tham gia vo cc th trng ln nht. Khng c s phn bit dch vCc tng i bao gi cng ch cung cp tp cc dch v cho ngi s dng nh i cuc gi n, chuyn cuc gi, xc nh s ch gi, hn ch cuc gi. Hu ht cc dch v ny u tn ti t nhiu nm qua, cc dch v hon ton mi tng i him. Th nht bi v s rt tn km khi pht trin v th nghim cc dch v mi, th hai cng bi v tp cc dch v hin c bao hm hu ht cc kh nng m mt khch hng c th thc hin trn cc nt bm in thoi ca mnh. Gii hn trong pht trin mngThng thng s u ni ca mng tng i chuyn mch knh l hnh cy, bao gm cc tng i quc t, n tng i Toll, tng i tandem, tng i host. C mi tng i mi c lp th n phi ni vi cc tng i i cp cao hn vi s u ni phc tp, mi hng kt ni th phi to ring cc lung truyn dn kt ni vi hai tng i iu ny gy kh khn cho vic u ni chuyn dn, mt khc khi b xung tng i mi th lu lng thoi cc trung k ni cc tng i lp trn ngy cng cao n mt lc no th phi nng cp m rng dung lng ca trung k . Khi khai mi mt u s trong ton mng th phI khai ht tt c trong cc tng i, iu ny gy mt rt nhiu thi gian v c th gp nhng s c khng ng c... M hnh t chc ca mng vin thng thng thy hin nay l : mt mng tng i TDM cp thp nht (lp 5, tng i ni ht, MSC ca mng di ng ...) c ni vi nhau bng mt mng li trung k im-im kh phc tp v ni ti tng i chuyn tip cp cao hn (lp 3, 4).

Hnh1: Cu trc mng v bo hiu ca mng PSTN

Mt s cuc gi (v d nh truy nhp hp th thoi hay quay s bng ging ni...) li c nh tuyn trc tip ti tng i chuyn tip s dng cc ti nguyn tp trung phc v cho cc dch v cao cp. Kin trc ny c s dng nhiu nm nay, v cng c ci tin rt nhiu nhm phc v cc ng dng thoi, tuy nhin vn c mt s gii hn: Chi ph iu hnh v bo dng cao, mt thi gian; vic nh li cu hnh v nng cp mng li phi tin hnh lin tc nhm trnh b nghn mng, hn na lun phi thit lp mng ln hn nhu cu thc t cho cc tng i chuyn tip. Cc trung k im - im hot ng vi hiu sut khng cao v chng c thit k hot ng c trong nhng gi cao im, v nhng gi cao im ny li khc nhau trong cc vng ca mng (v d thnh ph l ban ngy cn ngoi li l bui m). Nu c nhiu tng i chuyn tip trong mng, mi tng i li ni vi mt nhm cc tng i ni ht, cuc gi c th phi chuyn qua nhiu tng i chuyn tip n c ni lu gi ti nguyn mng (nh trong trng hp dch v hp th thoi). Trong mng NGN cc tng i TDM s c thay th bng cc tng i chuyn mch mm(Softswitch) . Kt ni cc softswitch l mng chuyn mch gi a dch v IP/ATM/MPLS. Phn tip cn thu bao ca mng NGN l cc BAN (Broadband Access Node) v IAD (Integrated Access Device) h tr cc loi u cui nh my tnh, my in thoi IP, my in thoi thng thng... Mng NGN giao tip vi cc mng khc nh mng PSTN v mng di ng qua cc Media Gateway.1.2.2.Cng ngh chuyn mch mm theo quan im ca mt s nh pht trin Vy Cng ngh chuyn mch mm Softswitch l g ? y l mt cu hi c rt nhiu nh pht trin t ra. Softswitch c nhc n nh l mt khi nim mang tnh thng mi nhiu hn, v nhng tranh lun v nhm t n mt nh ngha k thut thng nht, chnh xc v Softswitch vn cn ang tip din. C th ni rng, mi nh pht trin nhn Softswitch di nhng gc khc nhau. Di y l cc nh ngha v Softswitch ca mt s nh pht trin: Theo Nortel, Softswitch l mt thnh t quan trng nht ca mng th h mi (NGN Next Generation Network). Theo Nortel nh ngha th Softswitch l mt phn mm theo m hnh m c th thc hin c nhng chc nng thng tin phn tn trn mt mi trng my tnh m v c nhng tnh nng ca mng chuyn mch thoi TDM truyn thng. Chuyn mch mm c th tch hp thng tin thoi, s liu v video, n c th phin dch giao thc gia cc mng khc nhau v d nh gia mng v tuyn v mng cp. Softswitch cng cho php trin khai cc dch v VoIP mang li li nhun. Mt chuyn mch mm kt hp tnh nng ca cc chuyn mch thoi lp 4 (tng i chuyn tip/lin i) v lp 5 (tng i ni ht) vi cc cng VoIP, trong khi vn hot ng trn mi trng my tnh m chun. Cc h thng my tnh kin trc m s dng cc thnh phn c chun ho v s dng rng ri ca nhiu nh cung cp khc nhau. y, h thng my tnh c th l mt my tnh c nh cho ti nhng server c ln nh Netra ca Sun Microsystem. S dng cc h thng my tnh m cho php cc nh khai thc pht trin dch v mt cch c lp vi phn cng v hng li ch t nh lut Moore trong ngnh cng nghip my tnh. Theo MobileIN, Softswitch l tng v vic tch phn cng mng ra khi phn mm mng. Trong mng chuyn mch knh truyn thng, phn cng v phn mm khng c lp vi nhau. Mng chuyn mch knh da trn nhng thit b chuyn dng cho vic kt ni v c thit k vi mc ch phc v thng tin thoi. Nhng mng da trn chuyn mch gi hiu qu hn th s dng giao thc Internet (IP) nh tuyn thng tin thoi v s liu qua cc con ng khc nhau v qua cc thit b c chia s. Cn theo CopperCom, Softswitch l tn gi dng cho mt phng php tip cn mi trong chuyn mch thoi c th gip gii quyt c cc thiu st ca cc chuyn mch trong tng i ni ht truyn thng. Cng ngh Softswitch c th lm gim gi thnh ca cc chuyn mch ni ht, v cho ta mt cng c hu hiu to ra s khc bit v dch v gia cc nh cung cp dch v v n gin ho qu trnh dch chuyn t mng truyn thng sang mng h tr thoi gi t u cui n u cui (end - to - end) trong tng lai. Ngnh cng nghip vin thng dng nh t c mt s nht tr rng cu tr li tt nht l tch chc nng x l cuc ca ra khi thit b chuyn mch vt l, v kt ni hai thnh phn ny vi nhau thng qua mt lot cc giao thc chun. Trong , chc nng chuyn mch vt l - to cc kt ni cho trao i thng tin - do mng c s h tng mng m nhim. Chc nng ny trong cc mng chuyn mch gi c thc hin mt cch phn tn trong ton mng. Cn phn iu khin cc kt ni (thit lp, gii phng v cc tnh nng lin quan) th do mt b phn trung tm m nhim. B phn ny lm vic vi cc phn khc ca mng thng qua cc giao thc chun, do chc nng c thc hin vi mt tp hp cc m un phn mm. C mt s l do m theo ngi ta tin rng vic phn chia hai chc nng l mt gii php tt nht: To c hi cho mt s cng ty nh v linh hot vn vn ch tp trung vo phn mm x k cuc gi hoc vo phn mm chuyn mch gi gy c nh hng trong nghnh cng nghip vin thng ging nh cc nh cung cp ln t trc ti nay vn kim sot th trng. Cho php c mt gii php phn mm chung cho x l cuc gi ci t trn rt nhiu loi mng khc nhau, bao gm c mng chuyn mch knh v mng gi s dng cc khun dng gi v phng thc truyn dn khc nhau. L ng lc cho cc h iu hnh, cc mi trng my tnh chun, tit kim ng k trong vic pht trin pht trin v ng dng cc phn mm x l cuc gi. Cho php cc phn mm thng minh ca cc nh cung cp dch v iu khin t xa cc thit b chuyn mch t ti tr s ca khch hng, mt yu t quan trng trong vic khai thc ht tim nng ca mng trong tng lai.0. nh ngha chuyn mch mm (Softswitch)Chuyn mch mm c th c nh ngha nh l tp hp cc sn phm, giao thc, v cc ng dng cho php bt k thit b no truy cp cc dch v truyn thng qua mng xy dng trn nn cng ngh chuyn mch gi thng l IP (Internet Protocol). Nhng dch v bao gm thoi, fax, video, d liu v cc dch v mi c th c pht trin trong tng lai. Nhng thit b u cui truy nhp bao gm in thoi truyn thng, in thoi IP, my tnh, PDAs, my nhn tin (pager)...Mt sn phm Softswitch c th bao gm mt hoc nhiu phn chc nng, cc chc nng c th cng nm trn mt h thng hoc phn tn trn nhng h thng thit b khc nhau. Softswitch nhn trung cung cp cc chc nng ging nh cc chc nng ca h thng chuyn mch knh, n ch khc l c thit k cho mng chuyn mch gi v c kh nng lin kt vi mng PSTN. Cc tnh cht khc bit ca mt h thng chuyn mch mm bao gm: L h thng c kh nng lp trnh x l cuc gi v h tr cc giao thc ca mng PSTN, ATM, v IP. Hot ng trn nn cc my tnh v cc h iu hnh thng mi iu khin cc Gateway trung k ngoi (External Trunking Gateway), Gateway truy nhp(Access Gateway) v cc Server truy nhp t xa RAS(Remote Access Server) N ti s dng cc dch v IN thng qua giao din danh b m, mm do. Cung cp cc giao din lp trnh ng dng m API cho cc nh pht trin th 3 nhm to ra cc dch v th h sau. N c chc nng lp trnh cho cc h thng Back office C h thng qun l tin tin trn c s my ch (policy-Server-based) cho tt cc module phn mm.Mt c im na ca Softswitch l Softswitch khng phi lm nhim v cung cp knh kt ni nh tng i v lin kt thng tin c c s h tng mng NGN thc hin theo cc cng ngh chuyn mch gi. Tc l cng ngh Chuyn mch mm khng thc hin bt c chuyn mch g. Tt c cc cng vic ca Softswitch c thc hin vi mt h thng cc m un phn mm iu khin v giao tip vi cc phn khc ca mng NGN, chy trn mt h thng my ch c hiu nng, tin cy v sn sng cp nh cung cp dch v (Carrier -Class).1.2.4.Nhng li ch ca Softswitch i vi nh khai thc v s dngMng th h sau c kh nng cho ra i nhng dch v gi tr gia tng hon ton mi hi t ng dng thoi, s liu v video. Cc dch v ny ha hn em li doanh thu cao hn nhiu so vi cc dch v truyn thng.Do cc dch v ca NGN c vit trn cc phn mm . Do vic trin khai, nng cp, cng nh vic cung cp cc dch v mi cng tr nn d dng.Kh nng thu ht khch hng ca mng NGN rt cao, t s tin dng hi t c thoi d liu, video n hng lot cc dch v khc m nh cung cp dch v c th cung cp cho khch hng, thm na h c kh nng kim sot cc dch v thng tin ca mnh iu ny lm cho khch hng lun lun tho mn v l thuc hn vo nh cung cp dch v, c hi kinh doanh ca nh cung cp s ln hn, v n nh hn. Gim chi ph xy dng mng: Khi xy dng mt mng hon ton mi cng nh m rng mng c sn , th mng chuyn mch mm c ch ph t tn km hn nhiu so vi mng chuyn mch knh. iu ny lm cho tr ngi khi tham gia th trng ca nhng nh khai thc dch v mi khng cn ln nh trc na. Hin nay, s cnh tranh gia cc nh khai thc dch v chnh l nhng dch v g m h c th cung cp cho khch hng, v hi lng ca khch hng khi s dng nhng dch v , nn hu ht cc nh khai thc u tp trung u t vo vic vit phn mm pht trin dch v.Gim chi ph vn hnh bo dng v qun l mng hiu qu hn Softswitch khng cn cc tng i ln tp trung, tiu tn nng lng v nhn lc iu hnh, chuyn mch gi y s l cc my ch t phn tn trong mng, c iu khin bi cc giao din thn thin ngi s dng (GUI) do chi ph iu hnh v hot ng ca mng c gim ng k.S dng bng thng c hiu qu hn: Do mng truyn vn ca NGN l mng chuyn mch gi cho nn vi cng mt c s h tng truyn dn th hiu sut s dng bng thng ca n cao hn nhiu so vi mng chuyn mch knh. Thm na, theo nh thng k i vi thoi th 60% thi gian cuc gi l khong lng, mng th h mi c c ch trit khong lng nn lm tng hiu sut s dng bng thng mt mc ng k.Di y l mt s so snh gia cng ngh Chuyn mch mm v Tng i chuyn mch knh.

Hnh 1: Kin trc mng PSTN v mng th h mi NGN2.1. S ra i ca chuyn mch mm (Softswitch)Trong tng lai, mng th h mi s hon ton da trn c s h tng l mng gi. V th vic chuyn t mng vin thng hin ti ln mng th h mi phi tri qua nhiu giai on. Do PSTN hin ti vn hot ng tt v dch v do n cung cp kh tin cy (99.999%) nn vic chuyn c mng truy nhp v mng li ca PSTN thnh mng gi l rt tn km. tn dng s hot ng tt ca PSTN v u im ca chuyn mch gi, cu hnh mng NGN bao gm chuyn mch knh v chuyn mch gi c th hin nh trong hnh sau:

Hnh 2.1: Cu trc mng th h sau NGN

Theo hnh trn, tng i lp 5 hay tng i ni ht dng chuyn mch knh (circuit-switched local-exchange) (th hin qua phn mng PSTN) vn c s dng. Nh bit, phn phc tp nht trong nhng tng i ny chnh l phn mm dng iu khin qu trnh x l cuc gi. Phn mm ny chy trn mt b x l chuyn dng c tch hp sn vi phn cng vt l chuyn mch knh. Hay ni cch khc phn mm s dng trong cc tng i ni ht ph thuc vo phn cng ca tng i. iu ny gy kh khn cho vic tch hp mng PSTN v mng chuyn mch gi khi xy dng NGN - l mng da trn c s mng gi. Mt gii php c th thc thi l to ra mt thit b lai (hybrid device) c th chuyn mch thoi c dng knh v gi vi s tch hp ca phn mm x l cuc gi. iu ny c thc hin bng cch tch ring chc nng x l cuc gi khi chc nng chuyn mch vt l. Thit b chnh l MGC s dng chuyn mch mm Softswitch.Hay chuyn mch mm Softswitch chnh l thit b thc hin vic x l cuc gi trong mng NGN.2.2. Chuyn mch mm2.2.1. Khi nim chuyn mch mmHin nay c nhiu khi nim v chuyn mch mm, ty thuc vo tng hng vin thng khc nhau. Theo hng Mobile IN, Softswitch l tng v vic tch phn cng mng ra khi phn mm mng.Theo hng Nortel, Softswitch chnh l thnh phn quan trng nht ca mng th h tip sau. Softswitch l mt phn mm theo m hnh m, c th thc hin c nhng chc nng thng tin phn tn trn mt mi trng my tnh m v c chc nng ca mng chuyn mch thoi TDM truyn thng.Chuyn mch mm c th tch hp thng tin thoi, s liu v video v n c th phin dch giao thc gia cc mng khc nhau. Theo Coppercom, Softswitch l tn gi ca mt phng php mi trong chuyn mch thoi c th gip gii quyt c cc thiu st ca cc chuyn mch trong cc tng i ni ht truyn thng. Thc cht ca khi nim chuyn mch mm chnh l phn mm thc hin chc nng x l cuc gi trong h thng chuyn mch c kh nng chuyn ti nhiu loi thng tin vi cc giao thc khc nhau. (Ghi ch: chc nng x l cuc gi bao gm nh tuyn cuc gi v qun l, xc nh v thc thi cc c tnh cuc gi).Theo thut ng chuyn mch mm th chc nng chuyn mch vt l c thc hin bi cng phng tin Media Gateway (MG), cn x l cuc gi l chc nng ca b iu khin cng phng tin Media Gateway Controller (MGC).Mt s l do chnh cho thy vic tch 2 chc nng trn l mt gii php tt:- Cho php c mt gii php phn mm chung i vi vic x l cuc gi. V phn mm ny c ci t trn nhiu loi mng khc nhau, bao gm c mng chuyn mch knh v mng gi (p dng c vi cc dng gi v mi trng truyn dn khc nhau).- L ng lc cho cc h iu hnh, cc mi trng my tnh chun, tit kim ng k trong vic pht trin v ng dng cc phn mm x l cuc gi.- Cho php cc phn mm thng minh ca cc nh cung cp dch v iu khin t xa thit b chuyn mch t ti tr s ca khch hng, mt yu t quan trng trong vic khai thc tim nng ca mng trong tng lai.2.2.2. u im v ng dng ca chuyn mch mmu im:- Cho c hi mi v doanh thu:Vi cng ngh mng cho php hi t cc ng dng thoi, s liu, video cng cng ngh chuyn mch mi, nhiu dch v gi tr gia tng hon ton mi c ra i. Cc dch v ny ha hn s em li doanh thu cao hn so vi cc dch v thoi truyn thng.Do s dng cng ngh chuyn mch mm, c tnh cht phn tn, cc nh cung cp dch v c th cung cp dch v cho mt nhm nh khch hng, hay bt c ni no v khi no m h mun.-Thi gian tip cn th trng ngn:Do cng ngh chuyn mch mi da trn phn mm nn cc dch v mi ra i cng da trn phn mm. iu ny lm cho vic trin khai cc dch v mi cng nh nng cp dch v ang cung cp tr nn nhanh chng hn.Ngoi ra nh khai thc mng c th mua mt dch v mi t nh cung cp th ba trin khai nhanh chng dch v khch hng yu cu y chnh l mt trong nhng c im khc bit ca mng th h sau NGN m cc mng hin ti khng c .-Kh nng thu ht khch hng:Cng vi vic a vo s dng mng th h mi, vic a vo s dng chuyn mch mm cn gii thiu vi khch hng nhiu dch v mi hp dn ng thi cho php h t la chn v kim sot cc dch v thng tin do mnh s dng.-Gim chi ph xy dng mng:Chi ph xy dng cho cc h thng s dng chuyn mch mm l chi ph cho phn mm, khng theo kiu chi ph cho cc c cu chuyn mch knh trc y. Do khng i hi phi c vn u t ban u ln m chi ph xy dng s tng tuyn tnh theo nhu cu v s lng khch hng. Cc nh khai thc c th khi u phc v cho mt s lng nh khch hng nhng vn cung cp y cc dch v thng qua cc nh khai thc ln hn. y l im khc bit v chuyn mch truyn thng lun c thit k vi tp tnh nng v qui m ln hn nhiu so vi s lng khch hng v nhu cu dch v thc t.-Gim chi ph iu hnh mng:Do phn mm chuyn mch th h mi Softswitch cho php khch hng t la chn v kim sot qu trnh s dng dch v ca mnh nn gip cho cng vic ca cc nh iu hnh mng c gim i mt phn. Hn th na, khi s dng chuyn mch mm s khng cn cc tng i ln tp trung, tiu tn nng lng v nhn lc iu hnh. Cc chuyn mch gi y s l cc my ch t phn tn trong mng v c iu khin bi cc giao din thn thin vi ngi dng.- S dng bng thng mt cch hiu qu:Vi m hnh truyn thng, h thng chuyn mch s thit lp mt knh dnh ring cho ngi gi v ngi c gi trong cuc gi thng thng. V knh ny s khng c s dng cho mc ch no khc trong sut qu trnh kt ni. Tuy TDM cho php truyn nhiu knh trn mt trung k nhng knh dnh ring vn s dng ti nguyn mng nhiu hn mc yu cu thc t v tn ti nhng khong lng trong qu trnh m thoi.Khi a mng th h mi vo s dng, do mng IP c s dng nn tn dng c u im s dng bng thng hiu qu .- Qun l mng hiu qu: l do Softswitch cho php gim st v iu chnh hot ng mng theo thi gian thc ng thi c th nng cp hay thay i cu hnh mng t xa. iu ny gip cho cc nh iu hnh qun l mng hiu qu hn.- Ci thin dch v:Vi kh nng cung cp dch v mt cch d dng gip cho Softswitch nhanh chng c chp nhn. Bng cch lp t thm mt my ch ng dng ring mi (cn gi l nng cp phn mm chuyn mch Softswitch) hay trin khai thm mt module ca nh cung cp th 3, cc nh khai thc c th cung cp cc dch v mi nhanh chng hn v gi thp hn so vi chuyn mch truyn thng.Ngoi ra chuyn mch mm cn h tr nhiu tnh nng gip nh khai thc phn bit dch v cho tng khch hng ring l.- Tit kim khng gian t thit b:Softswitch cho php cc ng dng c thi hnh ti bt c khu vc no trn mng. Mng c th c sp xp sao cho cc my ch c b tr gn nhng ni m n tht s l ti nguyn quan trng.Cc ng dng v ti nguyn c nhim v cung cp cc dch v v tnh nng mi khng nht thit phi t ti cng mt ni trn mng.Hn th na cc thnh phn ca mng NGN, c bit l cc MGC s dng chuyn mch mm Softswitch c kch thc nh v c tnh phn tn nn khng gian t thit b cng gn hn.- Cung cp mi trng to lp dch v mm do:Do dch v c to ra nh phn mm nn mi trng to lp dch v mi rt linh hot.- An ton vn u t:Do mng NGN hot ng trn nn h tng c s c sn nn cc nh khai thc vn tip tc s dng mng truyn thng ng thi trin khai nhng dch v mi. iu ny gip nh khai thc va thu hi vn u t vo mng c va thu li nhun t dch v do mng mi cung cp.ng dng:Chuyn mch mm Softswitch hin nay, khi vn tn dng mng PSTN, c s dng trong mng cng cng thay th cho tng i cp 4 (tandem switch) v trong mng ring. V phn mm iu khin chuyn mch lc ny ch c nhim v n gin l thit lp v kt thc cuc gi.Trong tng lai khi tin ln mng NGN hon ton th cc MGC s dng Softswitch s thay th c cc tng i ni ht (lp 5). Khi chuyn mch mm Softswitch khng ch thit lp v xa cuc gi m s thc hin c cc chc nng phc tp khc ca mt tng i lp 5.2.3.V tr ca chuyn mch mm trong m hnh phn lp chc nng ca NGNDo c chc nng l x l cuc gi (Call control) nn v tr tng ng ca Softswitch trong m hnh phn lp chc nng ca NGN l lp iu khin cuc gi v bo hiu (Call Control and Signaling Layer). V cc thc th chc nng ca Softswitch l MGC-F, CA-F, IW-F, R-F v A-F.

Hnh 2.2: V tr chuyn mch mm Softswitch trong m hnh phn lp chc nng ca NGN2.4. Thnh phn chnh ca chuyn mch mm :Thnh phn chnh ca chuyn mch mm Softswitch l b iu khin cng thit b Media Gateway Controller (MGC). Bn cnh cn c cc thnh phn khc h tr hot ng nh: Signaling Gateway (SG), Media Gateway (MG), Media Server (MS), Application Server (AS)/Feature Server (FS).Trong Media Gateway l thnh phn nm trn lp Media Layer, Signaling Gateway l thnh phn trn cng lp vi MGC; Media Server v Application Server/Feature Server nm trn lp Application and Service Layer. Cch kt ni cc thnh phn trn c th hin hnh sau:

Hnh 2.3: Kt ni MGC vi cc thnh phn khc ca mng th h sau NGNGhi ch: cc thit b thuc mng IP l cc router, cc chuyn mch thuc mng backbone truyn ti cc gi tin i. Trong khi mng khng IP (non IP network) l mng c cc thit b u cui khng phi thuc mng IP v cc mng v tuyn khng dy. V d v cc thit b u cui khng thuc mng IP: thit b u cui ISDN, IAD (Integrated Access Device) cho mng DSL, ...Mt Media Gateway Controller c th qun l nhiu Media Gateway. Hnh trn ch minh ha 1 MGC qun l 1 MG. V mt Media Gateway c th ni n nhiu loi mng khc nhau.2.4.1. Media Gateway ControllerMGC chnh l thnh phn chnh ca chuyn mch mm, v cng thng c gi l Softswitch, hay Call Agent. Cc chc nng chnh ca MGC c th hin trong hnh sau:

Hnh 2.4: Chc nng ca khi iu khin cng phng tinCh thch: CA-F v IW-F l 2 chc nng con ca MGC-F. CA-F c kch hot khi MGC-F thc hin vic iu khin cuc gi. V IW-F c kch hot khi MGC-F thc hin cc bo hiu gia cc mng bo hiu khc nhau. Ring thc th chc nng Inter-operator Manager c nhim v lin lc, trao i thng tin gia cc MGC vi nhau. Media Gateway Controller c nhim v to cu ni gia cc mng c c tnh khc nhau bao gm PSTN, SS7, IP.Cc chc nng chnh ca Media Gateway Controller:- iu khin cuc gi, duy tr trng thi ca mi cuc gi trn mt Media Gateway.- iu khin v h tr hot ng ca Media Gateway, Signaling Gateway.- Trao i cc bn tin c bn gia 2 MG-F.- X l bn tin SS7 (khi s dng SIGTRAN).- X l bn tin lin quan QOS.- Pht hoc nhn bn tin bo hiu.- nh tuyn (bao gm bng nh tuyn, phn tch s v dch s).- Tng tc vi AS-F cung cp dch v hay c tnh cho ngi s dng.- C th qun l cc ti nguyn mng (port, bng tn, ...).Cc giao thc Media Gateway Controller c th s dng:+ Qun l cuc gi+ Thc hin nh tuyn cuc gi.+ Ghi li cc thng tin chi tit ca cuc gi tnh cc CDR( Call Detail Record ).+ iu khin qun l bng thng.+ thit lp cuc gi: H.323, SIP.+ iu khin Media Gateway: MGCP, Megaco/H.248.+ iu khin Signaling Gateway: SIGTRAN (SS7).+ truyn thng tin: RTP, RTCP.Cc thnh phn mng ca NGN lin lc vi nhau qua cc giao thc c th hin trong hnh sau:

Hnh 2.5: Giao thc ng dng trong chuyn mch mm2.4.2. Media Gateway ( MG )Media Gateway cung cp phng tin truyn ti thng tin thoi, d liu, fax v video gia mng gi IP v mng PSTN. Trong mng PSTN, d liu thoi c mang trn knh DSO. truyn d liu ny vo mng gi, mu thoi cn c nn v ng gi. c bit y ngi ta s dng mt b s l tn hiu s DSP (Digital Signal Processors ) thc hin cc chc nng: chuyn i AD (Alalog to Digital ), nn m thoi/audio, trit ting di, b khong lng, m ho, ta to tn hiu thoi, truyn cc tn hiu DTMFCc chc nng chnh ca Media Gateway:+ Truyn d liu thoi s dng giao thc RTP ( Real Time Protocol ).+ Cung cp khe thi gian hay ti nguyn x l tn hiu s DSP ( Digital Signal Processors ) di s iu khin ca MGC. ng thi qun l ti nguyn DSP cho dch v ny.+ Qun l ti nguyn v kt ni.+ Cung cp kh nng thay nng cc card hay DSP.+ Cho php kh nng m rng MG nh: M rng cng cards, cc nt m khng lm thay i cc thnh phn khc trn mng.2.4.3. Signalling Gateway ( SG ):Signalling Gateway to ra mt chic cu gia mng bo hiu SS7 vi mng IP di s iu khin ca MGC. SG lm cho Softswitch ging nh mt nt SS7 trong mng bo hiu SS7. Nhim v ca SG l s l thng tin bo hiu.Cc chc nng ca Signalling Gateway:+ Cung cp mt kt ni vt l n mng bo hiu.+ Truyn thng tin bo hiu gia MGC v SG thng qua mng IP.+ Cung cp ng truyn dn cho thoi, d liu v cc mng d liu khc ( thc hin truyn d liu l nhim v ca MG ).+ Cung cp cc hot ng SS7 c s sn sng cao cho cc dch v vin thng yu cu thi gian thc.2.4.4 .Media Server:Media Server l thnh phn la chn ca Softswitch, c s dng x l cc thng tin c bit. Mt Media Server phi h tr phn cng DSP vi hiu sut cao nht.Cc chc nng ca mt Media Server:+ Chc nng voicemail c bn.+ Hp th fax tch hp cc bn tin ghi m trc (pre-recorded message ).+ Kh nng nhn ting ni (nu c ).+ Kh nng hi ngh truyn hnh (video conference ).+ Kh nng chuyn thoi sang vn bn (speech-to-text ).- Application Server (AS )/Feature Server ( FS ):c tnh l mt server mc ng dng cha mt lot cc dch v c doanh nghip. V hu ht cc server ny t qun l cc dch v v truyn thng qua mng IP nn chng khng rng buc nhiu vi Softswith v vic phn chia hay nhm cc thnh phn ng dng.Cc dch v cng thm c th trc thuc Call Agent, hoc cng c th thc hin mt cch c lp. Nhng ng dng ny giao tip vi Call Agent thng qua cc giao thc nh: SIP, H.323Chng thng c lp vi phn cng nhng li yu cu truy nhp c s d liu c trng.Chc nng ca FS: Xc nh tnh hp l v h tr cc thng s dch v thng thng cho h thng a chuyn mch.

3.ng dng ca cc cng ngh mng th h mi da trn softwitch 3.1ng dng cho phng pht thay i iu khin softwitch trn tt c cc cell phone bi mt ngi qun trPhng php ny s kt hp cc thit b cell phone, PDA, GPS cng vi mt phn mm ng dng cho php kt hp cc ngi dng cc thit b trn vi nhau v iu khin chng. Mi thit b trn u c modum nhn tn hiu GPS cng vi vic ci t phn mm trn n cho php khi to kt ni v giao tip cc thit b vi nhau. H thng ny c th gip cho vic giao tip gia cc ngi dng trong nhng iu kin c bit, nh khi chuyn ng vi vn tc cao, gip cho vic xc nh v tr, video conference v truyn video Cu trc hot ng nh hnh di y:Ngi qun tr ACS bt cell phoneS dng mt my tnh, ngi qun tr a vo tn ca chuyn mch c gn ti softwitch v bn tinNgi qun tr kt hp softwitch cng vi d liu c bit truyn ti server vi bn tin ca ngi s dng. Khi nhn c bn tin mng s t ng thay i nh dng trng thI v v tr ca cc bn tin vng vi cc mng khcBn tin t mt ngi s dng s c server chuyn ti mt ngi s dng khc hoc l cho ton mngHnh 1: Cu trc ca phng php thc hin

Hnh 2: Thit b ci t ng dng chuyn mch mm giao tip

3.2.ng dng lm SS7, PRI Gateway ( gim ti Internet )ng dng ny nhm vo cc nh khai thc dch v thoi, nhng doanh nghip ang tm kim mt gii php gi thnh thp cho chuyn mch knh truyn thng cung cp giao din PRI cho cc nh cung cp dch v Internet (ISP) phc v cc ng truy nhp Dial-up. Hin nay khi nhu cu truy cp internet bng n , cc ISP c khuynh hng m rng cc kt ni PRI gia Access Server ca h ni vi cc tng i chuyn mch s lm cho cc nh cung cp dch v nhanh chng cn ht cng PRI hin c. Mt khc n cn cung cp cc dch v nh mng ring o VPN cho php ngi s dng quay s truy cp vo cc mng Lan (kt hp vi mng IP ca nh cung cp) nh Intranet, Extranet, dch v ny rt hu dng cho nhng ngi i cng tc xa.Bn cnh vic thiu cc knh PRI, lu lng truy cp Internet qua ng dail-up lm qu ti v tc nghn cho mng chuyn mch knh. Bi v chuyn mch knh vn c thit k phc v cc cuc gi c di trung bnh ngn, nn khi khong thi gian trung bnh tng thm do truy cp Internet, c xu hng lm gim ti nguyn tng i hoc cung cp cho cc ISP cc knh PRI c lu lng ti thp.

Hnh3 : S truy cp Internet qua PRI ng dng Softswitch lm SS7 PRI Gateway l mt trong nhng gii php trong tnhhung ny. M hnh truy cp Internet qua PRI v SS7 c th hin trn hnh 6, trong khi mt thu bao khi to mt cuc gi ti ISP thng qua phn mm my tnh , GW s kt cui phin PPP, n cung cp cho user mt a ch IP, trong di a ch IP ca n. Sau s b gi c gi cho Softswitch, v Softswitch s ra lnh cho GW truyn thng kch hot th tc login vo mng thng qua phng thc RAS, bo hiu gia MG v MGC l MGCP. Thng thng trong th tc login vo mng th s thc hin nhng th tc sau nhn thc truy cp Authentication, nhn thc s dng dch v Authorization, tnh cc Accouting qua AAA Server.

Hnh 4: S truy cp Internet qua trung k SS7

3.3.ng dng cho vic tm kim nh tuyn cho mng th h miS dng softwitch tm kim v nh tuyn cho cuc gi t ngi s dng ti ch. Dch v qun l ny gi l tc nhn chuyn mch mm. Khi x l s tm kim thng tin v cuc gi trn mt bng cc nt mng chuyn mch mm v quyt nh nt chuyn mch mm no cn c kt ni ti. Thng tin v v tr c lin quan c xc nh bi vic cung cp thng tin cn thit v ch ca cuc gi. Chng trnh qun l dch v, u tin s nhn cuc gi sau chuyn cuc gi ny thng qua mng ca nh cung cp dch v ti chuyn mch mm gn nht bng cch gim vic cn thit s dng PSTN.

Hnh 5: Cu trc mng

Hnh 6: S khi thc hin

Hnh 7: Biu hin vic thc hin ca mng

0. ng dng cho phng php theo du cuc gi trn gateway trong mng th h miPhng php ny s c s dng trn mt NGN MG. Thit b chuyn mch mm s thm mt ch dn theo du ti bn tin H.248 c lin h ti cuc gi. MG s quyt nh bn tin nhn H.248 cn c theo du thng qua ch dn c thm vo c hay khng. Nu bn tin H.248 cn c theo du, th vic theo du cuc gi l mt dao dch ph thuc vo bn tin H.248.

Hnh 8: S thut ton

Hnh 9: M hnh cu trc ca chuyn mch trn cho mt TDM ca mt mng chuyn mch

Hnh 10: M hnh cu trc vt l ca NGN trn cng ngh softwitch

Hnh 11 :C ch bn tin trn giao thc H.248

Hnh 12: S minh ha vic x l u cui T1 v T2 v vic xa T1 v T2 trn ng cnh C1 thng qua bn tin H.248 ca MG

Hnh 13: S thut ton cho vic theo du cuc gi bi NGN MG

2.5.Trung k o - tng i chuyn mch gi chuyn tipM hnh mng tng i chuyn mch s hin nay hnh cy nn khi mt cuc gi xut pht t tng i host vng 1 gi sang tng i host ca vng 2 th cuc gi phi tri qua rt nhiu cc tng i chuyn tip, do rt tn nhiu ti nguyn ca mng. Mt khc chi ph vn hnh bo dng mng tng i cao v mt rt nhiu thi gian.Chuyn mch mm chnh l gii php cho vn trn. MGC cng vi cc MG thay th chc nng ca cc tng i chuyn mch knh trc y, cc tng i ni ht kt ni ti cc MG bng cc giao din chun TDM thng thng v vi MGC bng bo hiu s 7. V d khi sub A gi cho sub B th thng tin thoi s t thu bao A n tng i A - MG A qua mng IP n MG B ri tng i B cui cng kt cui cuc gi ti thu bao B, v mt logic ta thy Softswitch kt hp vi cc MG nh mt tng i chuyn tip cho cuc gi gia hai thu bao A v B.

Hnh 14: ng dng tng i chuyn mch gi tandem

M hnh ny mang li mt s li ch so vi m hnh mng chuyn mch knh:0. Loi b li trung k hot ng hiu sut khng cao, thay th chng bng cc siu xa l trong mng IP/ATM phc v cho cc cuc gi cn chuyn tip, gim ti cho cc tng i chuyn tip truyn thng hoc loi b chng hon ton.0. Gim c chi ph vn hnh v gim c s tng i chuyn tip, s trung k t hn (so vi mt mng li trc y), v trnh khng phi thit k cc mch TDM phc tp.0. Gim c mt s lng cc cng chuyn mch dng cho cc trung k gia cc tng i ni ht vi nhau.0. Truy nhp cc ti nguyn tp trung mt cch hiu qu hn.0. Hp nht thng tin thoi v s liu vo mt mng duy nht, qua gim vn u t v chi ph so vi cc mng ring bit hin nay cho thoi v s liu.Mt ng dng khc ca m hnh trn l dch v gi ng di VoIP, dch v ny c kh nng em li cc ph ch bng 30% cc ph ca cuc gi qua mng in thoi chuyn mch cng cng(PSTN). iu ny em li li ch to ln cho cc doanh nghip, c bit l nhng doanh nghip mi.2.6.Tng i chuyn mch ni hty chnh l m hnh pht trin trin dch v ca NGN, trong cc Access Gate way, v cc Resident Gateway vi dung lng t vi trm n hng ngn thu bao. Chng c th dng cho cc doanh nghip, cc khch sn, khu dn c. Khi nim tng i ni ht y c ngha l Softswitch+Access Gateway hay cc Resident Gateway. Trong m hnh tng i chuyn mch knh truyn thng th cc tng i chia lm cc cp v d host, tandem, toll... Trong mng NGN th khng c khi nim phn cp nh vy , mi tng i ni ht u c vai tr nh nhau chng u c chung mt Call center l softswitch. cc tng i ny s cung cp cho ngi s dng rt nhiu dch v nh: thoi , truy cp internet bng rng ADSL, kt ni vi mng truy cp khc qua giao din V5.x, kt ni trung k PRI, trung k SS7...

Hnh 15: Kin trc tng i chuyn mch gi ni ht2.7.Thoi trn bng thng rng

Hnh 16: Cc phn t trong trong ng dng VoBB Thoi trn bng thng rng l gii php cung cp thoi v cc dch v th h tip theo cng nh cc feature cho cc thu bao trn nn tng gi v cc thit b u cui c kt ni ti NGN thng k thut truy cp bng thng rng. V mt k thut c hai cch cc thu bao c th s dng gii php thoi trn bng thng rng c th hin l: Cc thit b IP ca ngi s dng (IP Customer Premise) Cc IP client v IP terminal.IP Customer PremiseL mt thit b truy cp m n nh v ti nh ca khch hng v c kh nng cung cp cc dch v thoi truyn thng hay ng kt ni vi PBX. C thoi v d liu u c th truyn t u cui ti u cui qua mng IP. Hnh 20 th hin m hnh ca IP Customer Premise trong mng NGN.

Hnh 17: S kt ni IAD, v Cusomer Premise GW C hai loi thit b ph bin nht: Thit b truy cp tch hp , tn hiu thoi POTS/ISDN s c s ho v ghp knh vi tn hiu d liu trc khi truyn ln ng truyn DSL ti DSLAM. Gateway thuc khch hng: Thit b ny linh hot hn na, n h tr thu bao v cc dch v nh IAD nhng c kt ni vi mng IP bng giao din d liu nh cc cable modem, DSL modem hay truy cp bng mch vng ni ht khng dy, cng nh Powerline.IP client v IP terminal

Hnh 18: ng dng NGN vi u cui IP, v IP client Dch v ny c p dng cho trng hp thoi gia cc thu bao s dng u cui IP thng qua cc giao thc H323, SIP . N pht trin ngy cng mnh m em li hiu qu ht sc to ln cho ngi, v d nh thoi, hi ngh truyn hnh, Video on demmand .... Cho php my tnh ca bn c cc thuc tnh ca mt in thoi. L in thoi IP nu bn mun s dng thit b in thoi thng thng Mt IP Client nh mt tng i IP (IP PBX).Ngoi ra t mng H323, SIP ngi s dng c th gi cho mng PSTN chi ph rtthp. Trong kin trc mng NGN cng h tr cc phn t iu khin trung tm camng H323, SIP l Gatekeeper v SIP.

III.Kt lun Softwitch mang li nhng u th ni bt cho mng th h mi nh chi ph thp hn, kh nng vn hnh bo dng d dng hn Cc ng dng cng ngh mng th h mi da trn softwitch ang c mt tc pht trin rt mnh m, ang m ra mt th trng y tim nng cho cc cng ty pht trin thit b vin thng.Th trng thit k cc ng dng da trn sofwitch khng ch bao gm phn cng m cn c mt th trng y tim nng na l pht trin cc ng dng cho sofwitch bng phn mm. y s l mt c hi rt ln i vi cc nc c ln cng nghip in t c b hn ch. Bi bo co a ra c mt s ng dng tiu biu ca mng th h mi da trn softwitch. Khi qut mt cch chung v cng ngh mng th h mi da gip cho ngi c c mt ci nhn khi qut hn v cc ng dng ca mng th h mi da trn softwitch.

IV.Tham kho1. . Method of call trace on media gateway of next generation network Dong Gua, Shenzhen1. . Internodal routing engine for a next generation network Glen MacArthur, Washington, NJ (US); Michael MacArthur, Randolph, Mangoba, Somit Ghosh1. . Method of renaming softswitch controls in all participants cell phones by an administrator Malcolm K.beyer, Jr, 92 Lighthouse Dr.Jupiter Inlet Colony1. . Mng vin thng th h sau - TS. Nguyn Qu Minh Hin Nxb Bu in 20021. . n tt nghip Mng NGN - Hong Tin