I HC CNG NGH THNG TIN & TRUYN THNG KHOA CNG NGH IN T & TRUYN THNG

BO CO THC TP CHUYN NGNH

ti:

TM HIU V MNG NGN V CNG NGH IP/MPLS

Ging vin hng dn: ThS. Nguyn Th Ngn Sinh vin thc hin: Hong Ngc Thnh Lp : TVT K8B

Thi Nguyn, thng 4/ 2013

M u
Ngy nay khi bc sang th k 21, k nguyn ca x hi ha thng tin. Xu hng quc t ha v ton cu ha i sng kinh t , chnh tr, vn ha x hi lm cho vai tr thng tin cng tr nn quan trng i vi tt c cc quc gia trn th gii. Vin thng khng nhng ng vai tr l mt ngnh cng nghip dch v m n cn l ng lc thc y s pht trin ca ton b i sng kinh t- x hi. Cng vi s pht trin nhy bc v cng ngh vin thng lm cho cc dch v vin thng ngy cng tr nn phong ph v a dng nhm tha mn nhng nhu cu ngy cng cao ca i sng x hi.. Dch v vin thng trong tng lai i hi phi tp trung rt nhiu tr tu, cc dch v thng minh ny pht trin theo hng m rng bng thng, kt hp dch v v hi t thoi - s liu, c nh - di ng trn c s chuyn mch gi IP v c s truyn dn thng tin quang. T cc nh qun l v khai thc mng hnh thnh ln nhng tng v mt cu trc mng mi nhm p ng c cc nhu cu m rng dch v m vn tn dng c c s h tng ca kin trc mng c, l cu trc mng vin thng th h mi mng NGN v cng ngh IP/MPLS Vi nhng suy ngh thi thc em thc hin n tt nghip vi ti: Tng quan v NGN v IP/MPLS Mc d c gng nhng vi thi gian v trnh cn hn ch nn ni dung n khng trnh khi nhng sai st. Em rt mong nhn c s gp ca cc thy gio, c gio v cc bn sinh vin khc. Thi Nguyn , ngy 12 thng 4 nm 2013 Sinh vin thc hin: Hong Ngc Thnh

CHNG I TNG QUAN V NGN

1.1 Xu hng th trng , mng v dch v vin thng

Trong nhng nm gn y, vi s pht trin vt bc ca cc cng ngh v dch v mi (IP, Internet, VoIP, Wireless), lu lng doanh thu v li nhun ca cc dch v Vin thng truyn thng u suy gim nhanh chng. Theo d bo: trong 10 nm ti doanh thu dch v thoi (c phn c nh v di ng) s ch tng 1% mc d lu lng tng gp 2 ln. Ti mt s th trng nh M v Chu u doanh thu t dch v thoi ang suy gim 1-3% hng nm
$ billion 1,200 1,000 800 600 400 200 0 + 3% pa + 1% pa

+ 12% pa

1990

1995

2000

2005

2010

2015

Hnh 1.1 Xu hng th trng So vi lu lng thoi VoIP, trong thi gian sp ti PSTN vn gi t trng ln trong dch v thoi, tuy nhin mc chnh lch cng nh gi tr tuyt i ngy cng gim dn

AT Kerney 2005

Hnh 1.2 Worldwide Voice revenues Cc dch v Di ng ngy cng thay th C nh Cc dch v bng rng pht trin thay th cc dch v bng hp nh in thoi VoIP v Internet Telephony c s dng ngy cng nhiu. Cc dch khc pht trin thay th dch v thoi: email, messaging Cnh tranh, gim cc

Dialup gim mnh, ko theo gim doanh thu trn ng dy in thoi.

Tng trng ca dch v bng rng trong cc nm ti s pht trin rt nhanh, mc d tnh hnh mt s nc c th rt khc nhau. Nhng nc mi bt u: n 0.91 Mil d tnh s pht trin 400%/nm, Vit Nam 0.25Mil d tnh s pht trin 200%/nm. Tp trung pht trin mnh cc dch v gi tr gia tng v cc dch v bng rng em li cc ngun doanh thu mi. Trong giai on ti y s l nhng ngun doanh thu chnh : High Speed Internet , VoD , Multi-channel IPTV , VAS, Telecommuting, VoIP , Video Conferencing

Hi nhp thoi, video v d liu cng vi s m rng th trng v xu hng ton cu ha dn ti vic cnh tranh mc khng th lng trc c trong th trng truyn thng, p lc ang ngy cng to ra khi nhiu cng ty ang s dng hiu qu ca cc mng a dch v chuyn mch gi hay cn gi l cc mng th h sau (NGN)

Hnh 1.3: Cc kh nng tin n mng NGN Trong xu hng pht trin mng tt c con ng gn nh hi t v mt mng gi l mng th h mi (NGN), bi l mng NGN cho thy rt nhiu tnh u vit ca n

Hnh 1.4: Li th ca mng NGN S hp nht ca cc mng l yu cu cn thit, mang li nhiu li ch cho nh khai thc dch v. i vi nh hng NGN mang li nhiu tnh nng c th p ng c nhiu yu cu ca khch hng nht l cc dch v bng rng nh: - Tng thm tnh mm do -Tp trung kh nng iu khin cuc gi thng qua chuyn mch mm (Softswitches) - C th tit kim bng thng - Thc s cung cp dch v multi-media

1.2 L do NGN ra i (s cn thit phi chuyn i sang mng NGN)

Mng PSTN hin ti da trn nn tng cng ngh TDM v h thng bo hiu s7(CCS7). V c bn mng ny vn c kh nng cung cp tt cc dch v vin thng bnh thng nh thoi hay Fax vi cht lng kh n nh. Song nhu cu ca bn thn

nh cung cp dch v ln khch hng ngy cng tng lm bc l nhng hn ch khng th khc phc c ca mng hin ti Ngy nay th trng vin thng trong nc v th gii ang trong cuc cnh tranh quyt lit do vic xa b c quyn nh nc v m ca t do cho tt c cc thnh phn kinh t. Cc nh cung cp dch v ang phi ng trc sc p gim gi thnh ng thi tng cht lng dch v. S xut hin v pht trin bng n ca dch v Internet dn n nhng thay i t bin v c s mng buc cc nh cung cp dch v phi thay i t duy. Di y l mt s hn ch ca mng hin ti: a. Cng nhc trong vic phn b bng thng: Mng PSTN da trn cng ngh TDM trong ng truyn c phn chia thnh cc khung c nh l 125s. Mi khung c chia thnh cc khe thi gian (Timeslot). Knh c s c tnh tng ng vi mt khe thi gian l 64Kb/s. iu ny dn n mt sbt li, v d nh i vi nhiu loi dch v i hi bng thng thp hn th cng khng c, hay nh i vi cc dch v c nhu cu bng thng thay i th TDM cng khng th p ng c. Cuc ni TDM c phn b lng bng thng c nh(Nx64Kb/s) v cc khe thi gian ny c chim c nh trong sut thi gian din ra cuc ni dn n lng ph bng thng. Chuyn mch gi qun l bng thng mm do theo nhu cu dch v nn hiu qu s dng bng thng cao hn rt nhiu. b. Kh khn cho vic t hp mng Trc y cc loi dch v vin thng khc nhau nh thoi, d liu hay video c cung cp trn cc mng tch bit nhau. N lc t hp tt c cc mng ny thnh mt mng duy nht c thc hin t nhng nm 80 vi m hnh mng ISDN bng hp. M hnh ny vn da trn nn cng ngh TDM v gp phi mt s kh khn nh tc thp, thit b mng phc tp. tng mng ISDN bng rng da trn nn cng ngh ATM c a ra song c v nh qu s v t i vi ngi tiu dng. V li ATM cng khng linh hot khi hot ng tc thp. Gii php IPoverATM nghe c v hp l hn.

c. Kh khn trong vic cung cp dch v mi Trong mng PSTN ton b phn thng minh ca mng u tp trung cc tng i. Dch v mi mun c trin khai phi bt u t tng i. iu ny dn n s thay i phn mm v i khi c phn cng ca tng i rt phc tp v tn km. Ngoi ra, nhu cu ca khch hng khng ngng tng v nhiu loi dch v mi khng th thc hin trn nn mng TDM d. u t cho mng PSTN ln, gi thit b cao, chi ph vn hnh mng ln, khng linh hot trong vic m rng h thng, vn u t tp trung ti cc trung tm chuyn mch . iu ny dng nh qu r rng. u t cho cc thit mng PSTN rt ln (so vi mng IP). Cc tng i thng rt t, u t c cc. Chi ph nhn cng cho vic vn hnh bo dng mng rt cao. Cc chc nng phn cng v phn mm u tp trung ti tng i nn rt kh khn khi cn thay i. Mng c nhiu cp gy phc tp trong vic phi hp h thng bo hiu, ng b v trin khai dch v mi. Ngoi ra, vic thit lp trung tm qun l mng, h thng tnh cc hay chm sc khch hng cng rt phc tp e. Gii hn trong pht trin mng Cc tng i chuyn mch ni ht u s dng k thut chuyn mch knh, trong cc knh thoi u c tc 64Kb/s. Qu trnh bo hiu v iu khin cuc gi lin h cht ch vi c cu chuyn mch. Ngy nay, nhng li ch v mt kinh t ca thoi gi ang thc y s pht trin ca c mng truy nhp v mng ng trc t chuyn mch knh sang gi. V bi v thoi gi ang dn c chp nhn rng ri trong c mng truy nhp v mng ng trc, cc tng i chuyn mch knh ni ht truyn thng ng vai tr cu ni ca c hai mng gi ny. Vic chuyn i gi sang knh phi c thc hin ti c hai u vo v ra ca chuyn mch knh, lm pht sinh nhng chi ph ph khng mong mun v tng thm tr truyn dn cho thng tin, c bit nh hng ti nhng thng tin nhy cm vi tr ng truyn nh tn hiu thoi Nu tn ti mt gii php m trong cc tng i ni ht c th cung cp dch v thoi v cc dch v tu chn khc ngay trn thit b chuyn mch gi, th s

khng phi thc hin cc chuyn i khng cn thit na. iu ny mang li li ch kp l gim chi ph v tng cht lng dch v (gim tr ng truyn). V cng l mt bc quan trng tin gn ti ci ch cui cng l mng NGN. f. Khng p ng c s tng trng nhanh ca cc dch v d liu S tht l ngy nay dch v Internet pht trin vi tc chng mt, lu lng Internet tng vi cp s nhn theo tng nm v trin vng s cn tng mnh vo nhng nm sau trong khi lu lng thoi c nh dng nh c xu hng bo ha thm ch gim mt s nc pht trin. Internet thm nhp vo mi gc cnh ca i sng x hi vi nhiu tng rt ngon mc nh: o to t xa, y t t xa, chnh ph in t hay tin hc ha x hi, v.v... Cc mng cung cp dch v s liu ni chung v Internet ni ring nu khng ci tin v p dng cng ngh mi th r rng s khng th p ng c nhng nhu cu ngy cng tng ny Vi yu cu v thay i cng ngh mng nh trn, mng th h sau NGN c gii thiu v ng dng 1 s quc gia.Thc tin ny cho thy cng ngh mng mi ny p ng yu cu v k thut v kinh doanh k trn. V vy mng vin thng Vit Nam khng c s la no chn khc l chuyn sang s dng cng ngh gi

1.3 Khi nim v NGN

Cho ti nay, mc d cc t chc vin thng quc t v cc nh cung cp thit b vin thng trn th gii u rt quan tm v nghin cu v chin lc pht trin NGN, nhng vn cha c mt nh ngha c th v chnh xc no cho mng NGN. Do nh ngha mng NGN nu ra y khng th bao hm ht mi chi tit v mng th h sau, nhng c th c coi l khi nim chung nht khi cp n NGN Khuyn ngh Y.2001 ca ITU-T ch r: Mng th h sau (NGN) l mng chuyn mch gi c kh nng cung cp cc dch v vin thng v to ra ng dng bng thng rng, cc cng ngh truyn ti m bo cht lng dch v v trong cc chc nng dch v c lp vi cc cng ngh truyn ti lin quan. N cho php truy nhp khng gii hn ti mng v l mi trng cnh tranh gia cc nh

cung cp dch v trn cc kiu dch v cung cp. N h tr tnh di ng ton cu cho cc dch v cung cp ti ngi s dng sao cho ng nht v m bo Nh vy, NGN c th hiu l mng c h tng thng tin duy nht da trn cng ngh chuyn mch gi, trin khai cc dch v mt cch a dng v nhanh chng, p ng s hi t gia thoi v s liu, gia c nh v di ng . Nhng kh nng v u im ca NGN bt ngun t s tin b ca cng ngh thng tin v cc u im ca cng ngh chuyn mch gi v truyn dn quang bng rng.

Hnh 1. Mng hp nht V NGN cng c th hiu l mng hp nht ca cc la mng hin c . hp nht c cn phi c mt s thay i ln v mt cng ngh , cc cng ngh nn tng lp truyn ti ( ATM , IP ,MPLS) cng nh cng ngh lp iu khin mng ( MGCP , MEGACO , SIP , BICC) ta s xem r hn nhng cng ngh ny v hot ng ca chng phn sau.

1.4 Cu trc mng NGN

Nhn chung cu trc mng th h mi bao gm cc lp: - Lp truy nhp (Access ) - Lp truyn ti (Transport / Core ) - Lp iu khin (Control)

- Lp qun l (Management)

Hnh 1.5 Cu trc mng NGN a . Lp truy nhp - Thnh phn: + Phn truy nhp bao gm cc thit b truy nhp ng vai tr giao din kt ni cc thit b u cui vo mng thng qua h thng mng ngoi vi cp ng, cp quang hay v tuyn + Cc thit b truy nhp tch hp IAD (Thu bao c th s dng mi k thut truy nhp nh Tng t, S, TDM, ATM, IP truy nhp vo mng dch v NGN) - Chc nng: + Nh tn gi, lp truy nhp cung cp cc kt ni gia thu bao u cui v mng ng trc (thuc lp truyn dn ) thng qua cng giao tip MGW thch hp

+ Mng NGN kt ni vi hu ht thit b u cui chun v khng chun nh cc thit b truy xut a dch v , in thoi IP , my tnh PC , tng i ni b PBX , in thoi POTS , in thoi ISDN , v tuyn , v tinh , Vo DSL , VoIP b . Lp truyn ti Phn truyn dn: - Thnh phn: + Cc node chuyn mch/Router(IP/ATM hay IP/MPLS), cc chuyn mch knh ca mng PSTN cc khi chuyn mch PLM nhng mng ng trc,k thut truyn ti chnh l IP hay IP/ATM + C cc h thng chuyn mch , h thng nh tuyn cuc gi - Chc nng: Lp truyn ti trong cu trc mng NGN bao gm c chc nng truyn dn v chuyn mch Lp truyn dn c kh nng h tr cc mc QoS khc nhau cho cng mt loi dch v v cho nhiu loi dch v khc nhau. N c kh nng lu tr li cc s kin xy ra trn mng(kch thc gi, tc gi, tr hon, t l mt gi v Jitter cho phpi vi mng chuyn mch gi; Bng thng v tr hon i vi mng chuyn mch knh TDM). Lp ng dng a ra yu cu v nng lc truyn ti v n s thc hin cc yu cu Phn trung gian -Thnh phn: +Cc cng truy nhp AG (Access Gateway) kt ni gia mng li v mng truy nhp, RG(Residental Gateway) kt ni mng li vi mng thu bao ti nh +Cc cng giao tip TG (Trunks Gateway) kt ni gia mng li v mng PSTN /ISDN, WG (Wireless GateWay) kt ni mng li vi mng di ng -Chc nng: +Lp truyn ti c kh nng tng thch cc k thut truy cp khc nhau vi k thut chuyn mch gi IP hay ATM ng trc .Hay ni cch khc,lp ny chu

trch nhim chuyn i cc loi mi trng sang mi trng truyn dn gi c p dng trn mng li v ngc li +Nh , cc node chuyn mch (ATM+IP) v cc h thng truyn dn s thc hin chc nng chuyn mch, nh tuyn cuc gi gia cc thu bao ca lp truy nhp di s iu khin ca cc thit b thuc lp iu khin c . Lp iu khin - Thnh phn: +Lp iu khin bao gm cc h thng iu khin m thnh phn chnh l Softswitch cn gi l Media Gateway Controller hay Call Agent c kt ni vi cc thnh phn khc kt ni cuc gi hay qun l a ch IP nh: SGW (Signaling Gateway), MS (Media Server), FS (Feature server), AS(Application Server) + Theo MSF (MultiService Switching Forum), lp iu khin cn c t chc theo kiu module c th bao gm mt s b iu khin c lp . V d cc b iu khin dnh ring cho dch v :Thoi bo hiu s 7 , ATM/SVC , IP/MPLS

Hnh 1.6 Cc thnh phn ca Softswitch

- Chc nng : Lp iu khin c nhim v kt ni cung cp cc dch v thng sut t u cui ti u cui vi bt k loi giao thc v bo hiu no.C th lp iu khin thc hin cc chc nng sau: + nh tuyn lu lng gia cc khi chuyn mch +Thit lp v yu cu iu chnh v thay i cc kt ni hoc cc lung , iu khin xp nhn gia cc giao din cng +Phn b lu lng v cc ch tiu cht lng i vi mi kt ni v thc hin gim st iu khin m bo QoS

+ Bo hiu u cui t cc trung k, cc cng trong kt ni vi lp Media.Thng k v ghi li nhng thng s v chi tit cuc gi v ng thi thc hin cc cnh bo + Thu nhn thng tin bo hiu t cc cng v chuyn cc thng tin ny ti cc thnh phn thch hp trong lp iu khin + Qun l v bo dng hot ng cc kt ni thuc phm vi iu khin . Thit lp v qun l hot ng ca cc lung yu cu i vi chc nng dch v trong mng . Bo hiu cc thnh phn ngang cp. d . Lp ng dng -Thnh phn : Lp ng dng bao gm cc nt thc thi dch v SEN (Service Excution Node), thc cht l cc server dch v cung cp cc ng dng cho khch hng thng qua lp truyn ti - Chc nng:Lp ng dng cung cp cc dch v c bng thng khc nhau v nhiu mc . Mt s loi dch v s thc hin lm ch vic thc hin iu khin logic ca chng v truy cp trc tip ti lp ng dng, cn mt s dch v khc s c iu khin t lp iu khin nh dch v thoi truyn thng.Lp ng dng lin kt vi lp iu khin thng qua cc giao din m API. Nh cc nh cung cp dch v c th pht trin cc ng dng v trin khai nhanh chng trn cc mng dch v. Mt s v d v cc loi ng dng dch v c a ra sau y: +Cc dch v thoi +Cc dch v thng tin v n dung +VPN cho thoi v s liu +Video theo yu cu +Nhm cc dch v a phng tin +Thng mi in t +Games Online thi gian thc

e . Lp qun l -Lp qun l l mt lp c bit xuyn sut cc lp t lp kt ni ti lp ng dng Ti lp qun l, ngi ta c th trin khai k hoch xy dng mng gim st vin thng TMN, nh mt mng ring theo di v iu phi cc thnh phn vin thng ang hot ng.Tuy nhin cn phn bit cc chc nng qun l vi cc chc nng iu khin.V cn bn NGN da trn cc giao din m v cung cp rt nhiu loi hnh dch v trong mt mng n , cho nn mng qun l phi lm vic trong mt mi trng a nh u t, a nh khai thc vi nhiu loi hnh dch v c khai thc - Nhim v ca cc thc th nh sau : +AS-F (Application Server Function): y l thc th thi hnh cc dng/dich v +MS-F (Media Server Function): Cung cp cc dch v tng cng cho x l cuc gi. N hot ng nh mt Server x l cc yu cu t AS-F hoc MGC-F +MGC-F (Media Gateway Controller Function): Cung cp logic cuc gi v tn hiu bo hiu x l cuc gi cho mt hay nhiu Media Gateway +CA-F (Call Agent Function): L mt phn chc nng ca MGS-F,thc th ny c kch hot khi MGC-F thc hin vic iu khin cuc gi +IW-F (Interworking Function): Cng l mt phn chc nng ca MGC-F n c kch hot khi MGC-F thc hin cc bo hiu gia cc mng bo hiu khc nhau +R-F (Routing Function): Cung cp thng tin nh tuyn cho MGC-F + A-F (Accounting Function): Cung cp thng tin tnh cc + SG-F (Signaling Gateway Function): Dng chuyn thng tin bo hiu ca mng PSTN qua mng IP + MG-F (Media Gateway Function): Dng chuyn thng tin t dng truyn dn ny sang dng truyn dn khc ng dng nn nhim v chnh l cung cp cc logic dch v v thi hnh mt hay nhiu cc ng

1.5 Cc thnh phn c bn ca mng NGN

Mi tng quan gia cu trc phn lp chc nng v cc thnh phn chnh ca mng NGN c m t trong hnh

Hnh 1.7 Cc thnh chnh trong cu trc mng NGN Theo hnh 1.7 ta nhn thy, cc loi thit b u cui kt ni n mng truy nhp (Access Network), sau kt ni n cc cng truyn thng (Media Gateway) nm bin ca mng trc. Thit b quan trng nht ca NGN l SW nm tm ca mng trc (cn hay gi l mng li). SW iu khin cc chc nng chuyn mch v nh tuyn qua cc giao thc Trong mng vin thng th h mi c rt nhiu thnh phn cn quan tm, nhng y chng ta ch nghin cu nhng thnh phn chnh th hin r nt s tin tin ca NGN so vi mng vin thng truyn thng. C th l : 1.Media Gateway (MG) 2.Media Gateway Controller (MGC - Call Agent - Softswitch) 3.Signaling Gateway (SG)

4.Media Server (MS) 5.Application Server (Feature Server) M hnh cu trc mng v cc thnh phn chnh trong mng NGN:

Hnh 1.8: Cc thnh phn chnh trong NGN

1.5.1 Cng phng tin - Media Gateway (MG) Media Gateway cung cp phng tin truyn ti thng tin thoi, d liu, faxv video gia mng gi IP v mng PSTN. Trong mng PSTN, d liu thoi c mang trn knh DS0. truyn d liu ny vo mng gi, mu thoi cn c nn li v ng gi. c bit y ngi ta s dng mt b x l tn hiu s DSP (Digital Signal Processors) thc hin cc chc nng: chuyn i AD

(analog todigital), nn m thoi/audio, trit ting di, b khong lng, m ha, ti to tn hiu thoi, truyn cc tn hiu DTMF, Cc chc nng ca mt Media Gateway : Chc nng chnh ca Media Gateway l truyn d liu thoi s dng giao thc RTP (Real Time Protocol). Cung cp khe thi gian T1 hay ti nguyn x l tn hiu s (DSP Digital Signal Processing) di s iu khin ca MGC (Media GatewayController). ng thi qun l ti nguyn DSP cho dch v ny. Hn na MediaGateway cn h tr cc giao thc c nh loop-start, ground-start, E&M, CAS,QSIG v ISDN qua ng truyn T1v qun l ti nguyn, kt ni T1, cung cp kh nng thay nng cc card T1 hay DSP. Trong h thng mng sn c phn mm d phng Media Gateway cho php m rng cc Media Gateway v cng, cards, cc nt m khng lm thay i cc thnh phn khc trong mng. c tnh h thng: Mt Media Gateway l mt thit b vo/ra c hiu (I/O). Dung lng b nh lun m bo lu tr cc thng tin trng thi, thng tin cu hnh, cc bn tin MGCP,th vin DSPDung lng a ch yu s dng cho qu trnh ng nhp (logging). Qu trnh d phng y giao din Ethernet (vi mng IP), m rng mt vi giaodin T1/E1 vi mng TDM vi mt khong 120 port (DSOs) v s dng busH.110 m bo tnh linh ng cho h thng ni b

1.5.2 B iu khin cng phng tin - Media Gateway Controller (MGC) MGC l n v chc nng chnh ca Softswitch. N a ra cc quy lut x l cuc gi, cn MG v SG s thc hin cc quy lut . N iu khin SG thit lp v kt thc cuc gi. Ngoi ra n cn giao tip vi h thng OSS v BSS. MGC chnh l chic cu ni gia cc mng c c tnh khc nhau, nh PSTN, SS7, mng IP. N chu trch nhim qun l lu lng thoi v d liu qua cc mng khc nhau. N cn c gi l Call Agent do chc nng iu khin cc bn tin. Mt MGC kt hp vi MG, SG to thnh cu hnh ti thiu cho Softswitch.

Cc chc nng ca Media Gateway Controller: Chc nng ch yu l qun l cuc gi, s dng cc giao thc thit lp cuc githoi nh H.323, SIP v cc giao thc iu khin truyn thng nh MGCP, Megaco H.248. Chc nng tip theo l chc nng qun l lp dch v v cht lng dch vvi giao thc qun l SS7 SIGTRAN (SS7 over IP) v x l bo hiu SS7. Ngoi ra, MGC cn qun l cc bn tin lin quan QoS nh RTCP, thc hin nh tuyn cuc gi, ghi li cc thng tin chi tit ca cuc gi tnh cc (CDR- Call Detail Record) v iu khin qun l bng thng. i vi Media Gateway, MGC c cc chc nng: Xc nh v cu hnh thi gian thc cho cc DSP. Phn b knh DS0. Truyn dn thoi ( m ha, nn, ng gi). i vi Signaling Gateway, MGC cung cp : Cc loi SS7. Cc b x l thi gian. Cu hnh kt ni. M ca nt mng hay thng tin cu hnh. ng k Gatekeeper. 1.5.3 Cng bo hiu SG - Signalling Gateway Signaling Gateway to ra mt chic cu gia mng bo hiu SS7 vi mng IP di s iu khin ca Media Gateway Controller (MGC). SG lm cho MGC ging nh mt nt SS7 trong mng bo hiu SS7. Nhim v ca SG l x l thng tin bo hiu. Cng bo hiu m nhim cc chc nng sau: Cung cp vic lin kt bo hiu gia mng TDM v mng gi.

 Ph thuc vo loi bo hiu s dng (ISUP, ISDN, V5.2 ), SIGTRAN c s dng hiu qu (m bo thi gian thc) v tin cy (h tr khng mt gi v jitter trong mng gi). Vi thoi v bo hiu c nhn trn cng mt knh, chc nng SG thng c tch hp trn MG. Vi ISUP quasi-associated (s dng STP) th SG l thit b c lp. 1.5.4 My ch phng tin (MS - Media Server) MS l thnh phn la chn ca Softswitch, c s dng x l cc thng tin c bit. MS cung cp chc nng tng tc gia ngi gi v cc ng dng thng qua thit b vin thng. MS phn pht dch v thoi v video trn mng gi nh cu hi ngh ( nu dch v ny khng c MG h tr ), thng bo ( thng bo n gin do MG gi ), IN v mt s tng tc ngi dng. Chc nng MS c th c tch hp trong Softswith hoc MG. Cc chc nng ny c th l bt buc hoc la chn. C hai nhm chc nng chnh l: Cc chc nng ti nguyn phng tin nh tch tone, tng hp thoi, phng tin nhn dng ting ni, Cc chc nng iu khin phng tin nh nhc, ghi bn tin, Trn th trng, MS l nhng thit b c iu khin bng SIP, MGCP hoc H.248/Megaco v l gii php ca SRPs (Service Resource Point) h tr cho IN. Mt MS phi h tr phn cng DSP vi hiu sut cao nht. 1.5.5 My My ch ng dng/c tnh (Application Server/Feature Server ) My ch c tnh (Feature Server) l mt my ch lp ng dng cha mt lot cc dch v ca doanh nghip. Chnh v vy n cn c gi l my ch ng dng thng mi (Application Server). 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 ngdng. 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 giaothc nh

SIP, H.323, Chng thng c lp vi phn cng nhng li yu cu truy nhp c s d liu c trng. Mc tiu chnh ca my ch ng dng l iu khin v qun l cc ng dng mt cch hiu qu, kinh t v nhanh chng. N cho php a ra cc dch v mi khng cn cp nht phn mm Softswith trong thi gian ngn. Mt dch v mi c th c pht trin bi bn thn cc nh khai thc mng. Cc my ch ng dng iu khin tt c cc logic v kt ni ng dng. Phn mm my ch ng dng c th n gin ha vic kt ni cc h thng web mi, cc h thng t trong cc v tr khc nhau v cc h thng k tha thng qua web clinet. Mt s tnh nng c bn ca cc my ch ng dng: Tnh nng chung Server ng dng phi cung cp s tch hp Web h tr giao din Web cho ngi qun l, khai thc, bo tr. Tnh nng xc thc v bo mt iu khin cc phn t mng thc hin xc thc, cp php v cc kh nng tnh ton cho cc dch v c cung cp Tr gip c ch ng k, c th l yu cu ng k SIP hoc H.323. Cung cp cc dch v bo mt nh m ha hay xc thc m bo truy cp bo mt ti cc dch v Tnh nng truyn thng Truyn thng vi cc ng dng trong hoc ngoi. Truyn thng vi cc my ch iu khin ti nguyn mng bn ngoi. Tnh nng cung cp d liu Cung cp c s d liu thu bao v dch v. Qun l giao dch trn c s ca cc lut ACID. Ni chung, nh qun tr giao dch hoc b gim st c thit k nhn thc khi nim ACID. Tnh nng hot ng, qun l v iu khin

 Qun l dch v, bao gm cc phn t lin quan n kim ton, c tnh dch v. Qun l h thng, bao gm cc phn t lin quan n hot ng, qun l v khai thc cc my ch ng dng ( v d nh qun l cnh bo, gim st c tnh, bt gi v khi phc h hng ). Qun l thi gian vng i dch v, bao gm tr gip s trin khai dch v, cung cp dch v, thu dch v, kch hot v gii kch hot dch v, xc nh phin bn ca dch v. Tnh nng thc hin dch v Tr gip thc hin a ng dng hay a trng hp ca cng ng dng. Mi trng tr gip thc hin dch v, bao gm tp cc kh nng c lp dch v truy cp cc h thng bn ngoi thng qua cc giao thc, giao din chng trnh ng dng qun l cc phin dch v, truy cp dch v, cc s kin v khai bo, ng nhp v tng tc logic dch v

1.6 Cc Cng Ngh Nn Tng Cho NGN

1.6.1 Cng ngh truyn dn Mt vn quan trng khi trin khai NGN l cc cng ngh p dng trn mng li phi sn sng. Trong cu trc mng th h mi, truyn dn l mt thnh phn ca lp truy nhp v truyn dn. Trong vng hai thp k va qua, cng ngh quang chng minh c l mt phng tin truyn ti thng tin hiu qu trn khong cch ln, v hin nay n l cng ngh ch o trong truyn dn trn mng li. Cc ci tin trong k thut ghp knh theo bc sng nng cao ng k hiu qu kinh t v truyn ti trn mng cp quang. Mt s im mnh ca h thng truyn dn trn cp quang c th k n l: -Hin nay trn 60% lu lng thng tin truyn i trn ton th gii c truyn trn mng quang.

- Cng ngh truyn dn quang SDH cho php to ng truyn dn tc c cao (n*155 Mb/s) vi kh nng bo v ca cc mch vng c s dng rng ri nhiu nc v Vit Nam. -Cng ngh WDM cho php s dng rng bng tn rt ln ca si quang bng cch kt hp mt s tn hiu ghp knh theo thi gian vi di cc bc sng khc nhau v c th s dng c cc ca s khng gian, thi gian v di bc sng. WDM cho php nng tc truyn dn ln ti 5 Gb/s, 10 Gb/s v 20 Gb/s. Nh vy, c th ni cng ngh truyn dn ca mng th h mi s l SDH, WDM vi kh nng hot ng mm do, linh hot, thun tin cho khai thc v iu hnh qun l. Cc tuyn truyn dn SDH hin c v ang c tip tc trin khai rng ri trn mng vin thng l s pht trin ng hng theo cu trc mng mi. Cn tip tc pht trin cc h thng truyn dn SDH v WDM, hn ch s dng cng ngh PDH. Ngoi ra, c th nhn thy rng th trng thng tin v tin trong khu vc c s pht trin mnh trong nhng nm gn y v s cn tip tc trong nhng nm ti. Cc loi hnh dch v v tinh rt pht trin nh: DTH tng tc, truy nhp Internet, cc dch v bng rng, HDTV, Ngoi cc ng dng ph bin i vi nhu cu thng tin qung b, vin thng nng thn, vi s s dng kt hp cc u im ca cng ngh CDMA, thng tin v tinh ngy cng c xu hng pht trin c bit trong lnh vc thng tin di ng v thng tin c nhn. Mt vn quan trng l ngy nay IP tr thnh giao din hon thin thc s cho cc mng li NGN. V vy cc mng truyn dn phi ti u cho iu khin lu lng IP. Mt gii php c tnh thuyt phc hin nay l hi t cc lp d liu v cc lp quang trong mng li. Vic hi t ny mang li mt s li th nh cung cp cc dch v tc cao, bo v dng thng tin lin tc cho mng quang vi chuyn mch nhn a giao thc MPLS.

1.6.2 Cng ngh truy nhp Trong xu hng pht trin NGN s duy tr nhiu loi hnh mng truy nhp vo mt mi truyn dn chung nh: - Mng truy nhp quang, - Mng truy nhp v tuyn, - Mng truy nhp cp ng s dng cc cng ngh ADSL, HDSL, - Cc mng truy nhp bng rng. Nhn chung l phi a dng ho cc phng thc truy nhp, c v tuyn v hu tuyn. Xu hng hin nay l tch cc pht trin v hon thin em vo ng dng rng ri cc cng ngh truy nhp tin tin nh truy nhp quang, truy nhp WLAN, truy nhp bng rng, c bit l trin khai rng hnh thc truy nhp ADSL v h thng di ng 3G. 1.6.3 Cng ngh chuyn mch Chuyn mch cng l mt thnh phn trong lp mng truyn ti ca NGN. So vi hnh thc chuyn mch TDM trc y th cng ngh chuyn mch trong NGN c nhng thay i ln. Mng th h mi da trn nn cng ngh chuyn mch gi, cho php hot ng vi nhiu tc v c kh nng cung cp nhiu loai hnh dch v khc nhau. S la chn cng ngh chuyn mch cho NGN c th l IP, ATM hay MPLS. Tuy nhin, nhng nghin cu hon thin v cng ngh MPLS gn y ha hn cng ngh ny s l cng ngh chuyn mch ch o trong NGN. Bn cnh , mt cng ngh khc l chuyn mch quang cng ang c nghin cu v ch to th nghim. Trong tng lai s c cc chuyn mch quang phn chia theo khng gian, theo thi gian hay theo di bc sng. Hy vng l cc chuyn mch quang tc cao s sm c ng dng trong thc t. Sau y l nhng nt khi qut v c im cng ngh, cc u nhc im cng nh l kh nng ng dng ca tng loi cng ngh chuyn mch nhc n trn.

ATM
Cng ngh ATM da trn c s ca phng php chuyn mch gi nhanh, trong thng tin c nhm vo cc gi tin c chiu di c nh v ngn. Cc chuyn mch ATM cho php hot ng vi nhiu tc v dch v khc nhau. ATM c hai c im quan trng. Th nht, ATM s dng cc gi c kch thc nh v c nh gi l t bo (cell).Cc t bo nh vi tc truyn ln s lm cho tr truyn v bin ng tr gim nh i vi cc dch v thi gian thc, ng thi cng s to iu kin cho vic hp knh tc cao c d dng hn. Th hai, ATM c kh nng nhm mt vi knh o thnh mt ng o nhm gip cho vic nh tuyn c d dng. nh tuyn trong ATM khc vi IP mt s im. ATM l cng ngh chuyn mch hng kt ni. Kt ni t im u n im cui phi c thit lp trckhi thng tin c gi i. ATM yu cu kt ni phi c thit lp thng qua bo hiu.Mtkhc, ATM khng thc hin nh tuyn ti cc nt trung gian. Tuyn kt ni xuyn sutcxcnh trc khi trao i d liu v c gi c nh trong sut thi gian kt ni. Trong qu trnh thit lp kt ni, cc tng i ATM trung gian cung cp cho kt ni mt nhn. Vicnythchinhai iu: dnh cho kt ni mt s ti nguyn v xy dng bng chuyn t bo ti mi tng i. Bng chuyn t bo ny c tnh cc b v ch cha thng tin v cc kt ni ang hot ng i qua tng i. iu ny khc vi thng tin v ton mng cha trong bng chuyn tin ca b nh tuyn IP. Qu trnh chuyn t bo qua tng i ATM cng tng t nh vic chuyn gi tin qua b nh tuyn. Tuy nhin, ATM c th chuyn mch nhanh hn v nhn gn trn t bo c kch thc c nh (nh hn ca IP), kch thc bng chuyn tin nh hn nhiu so vi ca b nh tuyn IP, v vic ny c thc hin trn cc thit b phn cng chuyn dng. Do vy, thng lng ca tng i ATM thng ln hn thng lng ca b nh tuyn IP truyn thng

IP over ATM

K thut ATM, do c cc tnh nng nh tc cao, cht lng dch v v iu khin lu lng nn c s dng rng ri trn mng ng trc IP. Khi yu cu tnh thi gian thc trn mng li cao, IP over ATM l k thut c th c ngh n.C th ni MPLS chnh l s ci tin ca IP over ATM, cho nn vic nhn li mt cht v k thut ny y cng l iu cn thit IP over ATM l k thut kiu xp chng, n xp IP (lp 3) ln trn ATM (lp 2). Do giao thc ca hai tng hon ton c lp vi nhau, gia chng phi nh mt lot giao thc na (nh NHRP, ARP,) mi m bo ni thng. iu hin nay trn thc t c ng dng rng ri. Nhng trong tnh trng mng li c m rng nhanh chng, cch xp chng cng gy ra nhiu vn cn xem xt li. Trc ht, vn ni bt nht l trong phng thc xp chng, khi cn thit lp, bodng hay g b lin kt gia cc im nt, s vic phi lm (nh s VC, lng tin iu khin) s tng theo cp s nhn (bnh phng ca s im nt). iu ny ct h gy nn nhiu phin phc,nht l khi mng li ngy cng rng ln th chi phi kiu s lm cho mng tr nn qu ti. Th hai l, phng thc xp chng s phn ct c mng li IP over ATM ra lm nhiu mng logic nh (LIS), cc LIS trn thc t u l trong mt mng vt l.Gia cc LIS dng b nh tuyn trung gian lin kt, iu ny s nh hng n vic truyn nhm gi tin gia cc LIS khc nhau. Mt khc, khi lu lng rt ln, nhng b nh tuyn ny s gy hin tng nghn c chai i vi bng rng. Hai im nu trn lm cho IP over ATM ch c th thch hp cho mng tng i nh nh mng x nghip, khng th p ng c nhu cu ca mng ng trc Internet trong tng lai. Trn thc t, c hai k thut IP v ATM ang tn ti vn yu km v kh nng m rng thm. Th ba l, vi phng thc chng xp, IP over ATM vn khng c cch no m bo QoS thc s.

Vn th t l c hai k thut IP v ATM t ban u u c thit k ring l, khng xt g n k thut kia, iu ny lm cho s ni thng gia hai bn phi da vo mt lot giao thc phc tp, cng vi cc b phc v x l cc giao thc ny. Cch lm nh th c th gy nh hng khng tt i vi tin cy ca mng ng trc. Cc k thut MPOA (Multiprotocol over ATM - a giao thc trn ATM), LANE (LAN Emulation - M phng LAN), cng chnh l kt qu nghin cu gii quyt cc vn , nhng cc gii thut ny u ch gii quyt c mt phn cc tn ti, nh vn QoS chng hn. Phng thc m cc k thut ny dng vn l phng thc chng xp, kh nng m rng vn khng . Hin nay xut hin mt loi k thut IP over ATM khng dng phng thc xp chng, m dng phng thc chuyn mch nhn, p dng phng thc tch hp. K thut ny chnh l c s ca MPLS. Cn 2 cng ngh chuyn mch na l IP v MPLS chng ta s tm hiu k hn chng sau.

Tng Kt Chng : Qua nhng phn c trnh by trn , c th thy c s ra i ca mng NGN l 1 s tt yu t nhu cu ca ngi s dng cng nh kh nng p ng ca h tng mng nc ta , NGN cng v ang c ng dng nhm p ng yu cu m rng v nng cao cht lng dch v . V m rng , nng cao cht lng dch v hn na th chng ta cng tm hiu v cng ngh IP/MPLS ( chng 2)

Chng 2: Tng quan v IP/MPLS

2.1. Gii Thiu Chung V MPLS

MPLS l mt cng ngh kt hp c im tt nht gia nh tuyn lp ba v chuyn mch lp hai cho php chuyn ti cc gi rt nhanh trong mng li (core) v nh tuyn tt mng bin (edge) bng cch da vo nhn (label). MPLS l mt phng php ci tin vic chuyn tip gi trn mng bng cch gn nhn vo mi gi IP, t bo ATM, hoc frame lp hai. Phng php chuyn mch nhn gip cc Router v cc b chuyn mch MPLS-enable ATM quyt nh theo ni dung nhn tt hn vic nh tuyn phc tp theo a ch IP ch. MPLS cho php cc ISP cung cp nhiu dch v khc nhau m khng cn phi b i c s h tng sn c. Cu trc MPLS c tnh mm do trong bt k s phi hp vi cng ngh lp hai no. MPLS h tr mi giao thc lp hai, trin khai hiu qu cc dch v IP trn mt mng chuyn mch IP. MPLS h tr vic to ra cc tuyn khc nhau gia ngun v ch trn mt ng trc Internet. Bng vic tch hp MPLS vo kin trc mng, cc ISP c th gim chi ph, tng li nhun, cung cp nhiu hiu qu khc nhau v t c hiu qu cnh tranh cao. c im mng MPLS: - Khng c MPLS API, cng khng c thnh phn giao thc pha host - MPLS ch nm trn cc router - MPLS l giao thc c lp nn c th hot ng cng vi giao thc khc IP nh IPX, ATM, Frame Relay, - MPLS gip n gin ho qu trnh nh tuyn v lm tng tnh linh ng ca cc tng trung gian Phng thc hot ng:

Thay th c ch nh tuyn lp ba bng c ch chuyn mch lp hai.MPLS hot ng trong li ca mng IP. Cc Router trong li phi enable MPLS trn tng giao tip. Nhn c gn thm vo gi IP khi gi i vo mng MPLS. Nhn c tch ra khi gi ra khi mng MPLS. Nhn (Label) c chn vo gia header lp ba v header lp hai. S dng nhn trong qu trnh gi gi sau khi thit lp ng i. MPLS tp trung vo qu trnh hon i nhn (Label Swapping). Mt trong nhng th mnh ca kin trc MPLS l t nh ngha chng nhn (Label Stack) K thut chuyn mch nhn khng phi l k thut mi. Frame relay v ATM cng s dng cng ngh ny chuyn cc khung (frame) hoc cc cell qua mng. Trong Frame relay, cc khung c di bt k, i vi ATM di ca cell l c nh bao gm phn mo u 5 byte v ti tin l 48 byte. Phn mo u ca cell ATM v khung ca Frame Relay tham chiu ti cc knh o m cell hoc khung ny nm trn . S tng quan gia Frame relay v ATM l ti mi bc nhy qua mng, gi tr nhn trong phn mo u b thay i. y chnh l s khc nhau trong chuyn tip ca gi IP. Khi mt route chuyn tip mt gi IP, n s khng thay i gi tr m gn lin vi ch n ca gi; hay ni cch khc n khng thay i a ch IP ch ca gi. Thc t l cc nhn MPLS thng c s dng chuyn tip cc gi v a ch IP ch khng cn ph bin trong MPLS na.

2.1.1 Cc li ch ca MPLS
Phn ny s gii thiu mt cch ngn gn nhng li ch ca vic s dng MPLS trong mng. Nhng li ch ny bao gm: - Vic s dng h tng mng thng nht - u im vt tri so vi m hnh IP over ATM - Giao thc cng bin (BGP) - li t do - M hnh peer to peer cho MPLS VPN - Chuyn lu lng quang - iu khin lu lng

Ta s xem xt v l do khng c thc chy MPLS. y l l do m c xem hp l u tin trong vic s dng MPLS nhng n khng phi l l do tt trin khai MPLS Li ch khng c thc (li ch v tc ): Mt trong nhng l do u tin a ra ca giao thc trao i nhn l s cn thit ci thin tc . Chuyn mch gi IP trn CPU c xem nh chm hn so vi chuyn mch gi gn nhn do chuyn mch gi gn nhn ch tm kim nhn trn cng ca gi. Mt b nh tuyn chuyn tip gi IP bng vic tm kim a ch IP ch trong phn mo u IP v tm kim kt ni tt nht trong bng nh tuyn. Vic tm kim ny ph thuc vo s thc hin ca tng nh cung cp ca b nh tuyn . Tuy nhin, bi v a ch IP c th l n hng hoc a hng (unicast hoc multicast) v c 4 octet ( 1 octer = 1 8 bit) nn vic tm kim c th rt phc tp. Vic tm kim phc tp cng c ngha l quyt nh chuyn tip gi IP mt mt thi gian . Thi gian gn y, cc ng kt ni trn nhng b nh tuyn c th c bng thng ln ti 40 Gbps. Mt b nh tuyn m c mt vi ng link tc cao khng c kh nng chuyn mch tt c nhng gi IP m ch s dng CPU a ra quyt nh chuyn tip. CPU tn ti ch yu s dng (iu khin) bng iu khin. Mt phng iu khin l mt tp cc giao thc thit lp mt mt phng d liu hoc mt phng chuyn tip. Cc thnh phn chnh ca mt phng iu khin bao gm giao thc nh tuyn, bng nh tuyn v chc nng iu khin khc hoc giao thc bo hiu c s dng cung cp mt phng d liu. Mt phng d liu l mt ng chuyn tip gi qua b nh tuyn hoc b chuyn mch. S chuyn mch ca cc gi - hay mt phng chuyn tip - hin nay c thc hin trn phn cng c xy dng ring, hoc thc hin trn mch tch hp chuyn dng (ASIC - Application specific intergrated circuits). Vic dng ASIC trong mt phng chuyn tip ca b nh tuyn dn n nhng gi IP c chuyn mch nhanh nh cc gi c dn nhn. Do , nu l do duy nht a MPLS

vo mng l tip tc thc hin vic chuyn mch cc gi nhanh hn qua mng, chnh l l do o S dng h tng mng n hp nht: Vi MPLS, tng l gn nhn cho gi i vo mng da trn a ch ch ca n hoc tiu chun trc cu hnh khc v chuyn mch tt c lu lng qua h tng chung. y l mt u im vt tri ca MPLS. Mt trong nhng l do m IP tr thnh giao thc duy nht nh hng ln ti mng trn ton th gii l bi v rt nhiu k thut c th c chuyn qua n. Khng ch l d liu (s liu) chuyn qua IP m cn c thoi. Bng vic s dng MPLS vi IP, ta c th m rng kh nng truyn loi d liu. Vic gn nhn vo gi cho php ta mang nhiu giao thc khc hn l ch c IP qua mng trc IP lp 3 MPLS-enabled, tng t vi nhng kh nng thc hin c vi mng Frame Relay hoc ATM lp 2. MPLS c th truyn IPv4, IPv6, Ethernet, iu khin kt ni d liu tc cao (HDLC), PPP, v nhng k thut lp 2 khc. Chc nng m ti bt k khung lp 2 c mang qua mng ng trc MPLS c gi l Any Transport over MPLS (AToM). Nhng b nh tuyn ang chuyn lu lng AToM khng cn thit phi bit ti MPLS; n ch cn c kh nng chuyn mch lu lng c dn nhn bng vic tm kim nhn trn u ca ti. V bn cht, chuyn mch nhn MPLS l mt cng thc n gin ca chuyn mch a giao thc trong mt mng. Ta cn phi c bng chuyn tip bao gm cc nhn n trao i vi nhn ra v bc tip theo. Tm li, AToM cho php nh cung cp dch v cung cp dch v cng lp 2 ti khch hng nh bt k mng khc. Ti cng mt thi im, nh cung cp dch v ch cn mt h tng mng n c th mang tt c cc loi lu lng ca khch hng.

2.1.2 c im vt tri ca MPLS so vi m hnh IP over ATM

Khi hp nht vi chuyn mch ATM, chuyn mch nhn tn dng nhng thun li ca cc t bo ATM - chiu di thch hp v chuyn vi tc cao.

Trong mng a dch v chuyn mch nhn cho php chuyn mch BPX/MGX nhm cung cp dch v ATM, Frame, Replay v IP Internet trn mt mt phng n trong mt ng i tc cao. Cc mt phng (Platform) cng cng h tr cc dch v ny tit kim chi ph v n gin ha hot ng cho nh cung cp a dch v. ISP s dng chuyn mch ATM trong mng li, chuyn mch nhn gip cc dng Cisco, BPX8600, MGX8800, Router chuyn mch a dch v 8540 v cc chuyn mch Cisco ATM gip qun l mng hiu qu hn xp chng (overlay) lp IP trn mng ATM. Chuyn mch nhn trnh nhng rc ri gy ra do c nhiu router ngang hng v h tr cu trc phn cp (hierarchical structure) trong mt mng ca ISP: - S tch hp: MPLS xc nhp tnh nng ca IP v ATM ch khng xp chng lp IP trn ATM. MPLS gip cho c s h tng ATM thy c nh tuyn IP v loi b cc yu cu nh x gia cc c tnh IP v ATM. MPLS khng cn a ch ATM v k thut nh tuyn - tin cy cao hn: Vi c s h tng ATM, MPLS c th kt hp hiu qu vi nhiu giao thc nh tuyn IP over ATM thit lp mt mng li (mesh) dch v cng cng gia cc router xung quanh mt m my ATM Tuy nhin c nhiu vn xy ra do cc PCV link gia cc router xp chng trn mng ATM. Cu trc mng ATM khng th thy b nh tuyn. Mt link ATM b hng lm hng nhiu router-to-router link, gy kh khn cho lng cp nht thng tin nh tuyn v nhiu tin trnh x l ko theo - Trc tip thc thi cc loi dch v: MPLS s dng hng i v b m ca ATM cung cp nhiu loi dch v khc nhau. N h tr quyn u tin IP v cp dch v CoS trn chuyn mch ATM m khng cn chuyn i phc tp sang cc lp ATM Forum Service - H tr hiu qu cho Mulicast v RSVP: Khc vi MPLS, xp lp IP trn ATM ny sinh nhiu bt li, c bit trong vic h tr cc dch v IP nh IP muticast v RSVP (giao thc dnh trc ti nguyn). MPLS h tr cc dch v ny, k tha thi gian v cng vic theo cc chun v khuyn khch to nn nh x xp x ca cc c trng IP&ATM

- S o lng v qun l VPN : MPLS c th tnh c cc dch v IP VPN v rt d qun l cc dch v VPN quan trng cung cp cc mng IP ring trong c s h tng ca n. Khi mt ISP cung cp dch v VPN h tr nhiu VPN ring trn mt c s h tng n.Vi mt ng trc MPLS, thng tin VPN ch c x l ti mt im ra vo.Cc gi mang nhn MPLS i qua mt ng trc v n im ra ng ca n. Kt hp MPLS vi MP- BGP (a giao thc cng bin) to ra cc dch v VNP da trn nn MPLS (MPLS-based VNP) d qun l hn vi s iu hnh chuyn tip qun l pha VNP v cc thnh vin VNP, dch v MPSL-based VNP cn c th m rng h tr hng trm nghn VPN - Gim ti trn mng li: Cc dch v VPN hng dn cch MPLS h tr mi thng tin nh tuyn phn cp . Hn na, c th tch ri cc nh tuyn Internet khi li mng cung cp dch v. Ging nh d liu VPN, MPSL ch cho php truy sut bng nh tuyn Internet ti im ra vo ca mng . Vi MPSL, k thut lu lng truyn bin ca AS c gn nhn lin kt vi im tng ng. S tch ri ca nh tuyn ni khi nh tuyn Internet y cng gip hn ch li, n nh v tng tnh bo mt. - Kh nng iu khin lu lng: MPLS cung cp cc kh nng iu khin lu lng sng dng hiu qu ti nguyn mng. K thut lu lng gip chuyn ti t cc phn qu ti sang cc phn cn ri ca mng da vo im ch, loi lu lng, ti, thi gian,

2.2. Cc khi nim c bn trong IP/MPLS

Multiprotocol Laber Switching (MPLS) c chun ha bi IETF trong RFC 303: l phng thc chuyn mch gi, nh tuyn cc gi tin da theo cc nhn. MPLS c xy dng k tha cc u im ca IP v ATM (Traffic Engineering v out-of-band control). Cc nhn MPLS c th da trn thng tin v a ch IP, QoS, cng vt l Nh lu lng c th c nh tuyn da theo cc thng tin a dng (QoS, Source).

Cng ngh MPLS c pht trin chuyn cc loi lu lng khc nhau: IP, ATM, SDH, Ethernet MPLS hot ng gia lp 2_DataLink v lp 3_Network theo m hnh OSI, v thng c coi l giao thc ti lp lp 2.5. IP/MPLS s dng header 32 bits chn gia phn header ca giao thc lp 3 v giao thc lp 2. Cc Router trong mng MPLS c gi l Label Switch Router (LSR) Trong mng MPLS, cc gi tin c truyn ti theo cc lp u tin khc nhau Forwading Equivalence Class (FEC). Cc gi tin trong cng 1 FEC c truyn trn cng mt ng v cng c t mt mc u tin nh nhau. Vic phn loi FEC cho mi gi tin ch thc hin mt ln ti im vo ca mng MPLS, ti LSR bin (Edge LSR).Ti im u vo cc gi tin s c gn nhn chuyn mch MPLS, v c bc nhn MPLS ti Edge LSR u ra. Cc tuyn ng m gc gi tin MPLS c chuyn mch t im LSR ngun ti LSR ch c gi l cc Label-switch path (LSP) Cc Edge LSR: thc hin nhim v gn nhn cho cc gi tin vo mng MPLS v tch b nhn ca cc gi tin ra khi mng MPLS. Ch cc Edge LSR mi cn xem bng nh tuyn IP. Cc LSR khc ch thc hin chc nng chuyn mch da vo nhn MPLS, tra bng nhn v thay i nhn tng ng (label swapping) Mi LSP ch c nh ngha l 1 knh thng tin 1 chiu, do cn phi thit lp 2 LSP cho cho 1 knh thng tin 2 chiu. C th thc hin vic phn ti (Load-sharing) theo nhiu LSP khc nhau gia 2 im .

2.3. Kin trc ca IP/MPLS

Cc LSR thc hin 3 chc nng c bn: Trao i thng tin nh tuyn Trao i nhn (insert, swap, remove)

 Vn chuyn cc gi tin

Hnh 2.1 Kin trc IP/MPLS Mt trong nhng u im ca MPLS l kin trc c phn chia thnh 2 mt phng r rt: mt phng iu khin (control plane) v mt phng d liu (data plane): Control plane: trao i cc thng tin nh tuyn Lp 3 nh: OSPF, IS-IS, BGP, v cc thng tin v nhn MPLS nh LDP, RSVP, TDP Control plane xy dng v duy tr ni dung ca bng chuyn mch nhn trn cc LSR. (LFIB_ Label Forwarding Information Base) Data plane: cc gi tin c vn chuyn da theo nhn.

2.4. Cc giao thc trong MPLS (LDP, RSVP, BGP..)

2.4.1 Giao thc phn phi nhn LDP

Hnh 2.2 Cc giao thc phn b nhn Giao thc phn b nhn l mt thit lp cc th tc bi mt LSR cho bit mt LSR khc nhn s dng chuyn hng lu lng gia v qua chng LDP c th hot ng gia cc LSR kt ni trc tip hay khng c kt ni trc tip. Cc LSR s dng LDP hon i thng tin rng buc FEC v nhn c gi l cc thc th ng cp LDP, chng hon i thng tin ny bng vic xy dng cc phin LDP Cc loi bn tin LDP: LDP nh ngha 4 loi bn tin l: Bn tin thm d, Bn tin phin, Bn tin pht hnh, Bn tin thng bo. Bn loi bn tin ny cng ni ln chc nng m n thc hin Bn tin thm d (Discovery): dng thng bo v duy tr s c mt ca 1 LSR trong mng. Theo nh k, LSR gi bn tin Hello qua cng UDP vi a ch multicast ca tt c cc router trn mng con

 Bn tin phin (Session): dng thit lp, duy tr, v xo cc phin gia cc LSR. Hot ng ny yu cu gi cc bn tin Initialization trn TCP. Sau khi hot ng ny hon thnh cc LSR tr thnh cc i tng ngang cp LDP Bn tin pht hnh (Advertisement): dng to, thay i v xo cc rng buc nhn vi cc FEC. Nhng bn tin ny cng mang trn TCP. Mt LSR c th yu cu 1 nh x nhn t LSR ln cn bt c khi no n cn. N cng pht hnh cc nh x nhn bt c khi no n mun mt i tng ngang cp LDP no s dng rng buc nhn Bn tin thng bo (Notification): dng cung cp cc thng bo li, thng tin chn on, v thng tin trng thi. Nhng bn tin ny cng mang trn TCP Tiu bn tin LDP:Mi mt bn tin LDP c gi l n v d liu giao thc PDU, c bt u bng tiu bn tin v sau l cc bn tin LDP nh trnh by trn y. Hnh sauch ra cc trng chc nng ca tiu LDP v cc trng ny thc hin cc chc nng sau:

Hnh 2.3 Tiu LDP -Phin bn: S phin bn ca giao thc, hin ti l phin bn 1 di PDU: Tng di ca PDU tnh theo octet, khng tnh trng phin bn v trng di -Nhn dng LDP: Nhn dng khng gian nhn ca LSR gi bn tin ny. Bn octet u tin cha a ch IP c gn cho LSR: nhn dng b nh tuyn. Hai octet cui nhn dng khng gian nhn bn trong LSR.Vi LSR c khng gian nhn ln, trng ny c gi tr bng 0.

Tt c cc bn tin LDP c khun dng sau:

Hnh 2.4 Khun dng cc bn tin LDP Bit U: bit bn tin cha bit. Nu bit ny bng 1 th n khng th c thng dch bi pha nhn, lc bn tin b b qua m khng c phn hi Kiu bn tin: Ch ra kiu bn tin l g Chiu di bn tin: Ch ra chiu di ca cc phn nhn dng bn tin, cc thng s bt buc, v cc thng s tu chn Nhn dng bn tin: l mt s nhn dng duy nht bn tin. Trng ny c th c s dng kt hp cc bn tin Thng bo vi mt bn tin khc Thng s bt buc, v Thng s tu chn tu thuc vo tng bn tin LDP

2.4.2 Giao thc d tr ti nguyn RSVP RSVP c in cho php cc b nh tuyn hot ng mm do lu gi li trng thi truyn dn kt ni ca chng, tt nhin RSVP s tng s phn pht khi s lng cc phin tng dn trong mng. lm cho RSVP c th trin khai trong phm vi mi trng MPLS, giao thc hin nay cn phi tng thm

Cc bn tin giao thc RSVP c tng ln vi mt i tng mi cung cp s cp pht nhn, s phn phi v s rng buc, dc theo cc b nh tuyn r rng. S thay i ng k c gii thiu ti c s giao thc RSVP hin nay l bao gm vic lm gim i c cu soft state, trong cc bn tin c gi i mt cch nh k duy tr ng dn v lm mi c cu gia cc c cu khc cho php RSVP c th cung cp ER-LSP. Hnh sau m t lung ca bn tin RSVP trong vic thit lp mt LSP:

Hnh 2.5 S m rng cho RSVP thit lp mt ER-LDP Nh tn gi ca n, giao thc dnh trc ti nguyn RSVP dng dnh trc cc ti nguyn cho mt phin lm vic (dng lu lng) trong mng Internet. Kha cnh ny ca Internet l khc so vi d nh thit k h thng nm bn di ban u l ch dng h tr cc dch v n lc ti a m khng xem xt n cc yu cu c xc nh trc v cht lng dch v hay c tnh lu lng ca ngi s dng RSVP c d tnh m bo hiu nng bng vic dnh trc cc ti nguyn cn thit ti mi node tham gia trong vic h tr dng lu lng (chng hn nh hi ngh video hay audio). Cn nh rng IP l giao thc khng hng kt ni, n khng thit lp trc ng i cho cc dng lu lng, trong khi RSVP thit lp trc nhng ng i ny v m bo cung cp bng tn cho ng i RSVP khng cung cp cc hot ng nh tuyn m s dng IPv4 hay IPv6 nh l c ch truyn ti ging nh cch m giao thc bn tin iu khin Internet (ICMP) v giao thc bn tin nhm Internet (IGMP) hot ng RSVP yu cu pha thu a ra tham s QoS cho dng lu lng. Cc ng dng pha thu phi xc nh bn ghi QoS v chuyn ti RSVP. Sau khi phn tch cc yu cu ny, RSVP gi cc yu cu ti tt c cc node tham gia trong vic vn chuyn dng lu lng Cc kha cnh ca RSVP lin quan ti MPLS RSVP l mt giao thc bo hiu c s dng thit lp cc yu cu dnh trc ti nguyn nhm m bo QoS trong Internet.Cht lng dch v ca mt dng lu lng no c thc hin bng cc k thut gi l iu khin lu lng. Nhng k thut ny bao gm (1) Mt b phn loi gi (2) iu khin chp nhn kt ni (3) Mt b lp lch gi v (4) iu khin chnh sch Cc phin: RSVP xc nh phin l mt dng lu lng vi mt a ch ch IP v giao thc lp vn chuyn no . Mt phin RSVP c xc nh bi a ch ch

IP DestAddress), nhn dng giao thc IP (ProtocolId), v nhn dng cng ch (DestPort). a ch ch IP ca gi d liu c th l a ch n hng hay a hng. ProtocolId l nhn dng giao thc IP. Tham s chc nng DestPort l mt cng ch c tng qut ha. DestPort c th c xc nh bi trng cng ch UDP/TCP, hay bi mt trng tng ng trong giao thc vn chuyn khc Cc bn tin chnh ca giao thc RSVP: RSVP yu cu pha thu a ra cc tham s QoS cho dng lu lng. Cc ng dng tip nhn dng lu lng n phi xc nh bn ghi QoS (cha cc tham s QoS) ri chuyn ti RSVP. Sau khi phn tch yu cu ny, RSVP gi cc bn tin yu cu ti tt c cc node tham gia vo vic vn chuyn dng lu lng. Nh c biu din trong hnh 2.6, cc hot ng c bt u bng bn tin Path RSVP. N c s dng bi pha gi thit lp mt ng i cho phin (dng lu lng)

Hnh 2.6 Cc bn tin Path v Reservation iu khin chp nhn v iu khin chnh sch : Nhn vo hnh 2.6 chng ta thy c qu trnh RSVP chuyn cc yu cu ti iu khin chp nhn v iu khin chnh sch. Nu s kim tra xy ra mt trong hai iu khin khng thnh cng, s dnh trc ti nguyn s b hu b v qu trnh RSVP tr li bn tin thng bo li ti pha nhn tng ng. Nu c hai s kim tra trong hai iu khin ny

thnh cng th node s cho php b phn loi gi la chn cc gi d liu - nh c xc nh bi filterspec v tng tc vi lp lin kt d liu tng ng t c QoS mong i - nh c xc nh bi flowspec. Trong phn ti chng ta s tm hiu v filterspec v flowspec nh tuyn hin: S m rng ca RSVP cng h tr nh tuyn hin, thng c bit nh l nh tuyn cng bc trong cc min MPLS. Hot ng ny c thc hin bng vic t i tng EXPLICIT_ROUTE vo trong bn tin Path

Hnh 2.7 i tng Session v Explicit Route

Xc nh cc node li vo v cc node li ra: i tng Session, nh c biu din trong hnh 2.7 l mt trng hu ch vi cc nh qun l mng mun iu khin cc node li vo v cc node li ra ca LSP m khng cn phi iu khin mi node t li vo n li ra. thc hin chc nng ny i tng Session phi cha a chi IP ca node li ra Cc mc u tin ca phin : Mt trng khc c nh ngha trong RSVP m rng l Session Attibute. N c s dng bi cc node RSVP/MPLS nhn ra u tin ca dng lu lng (LSP trong MPLS) tng ng vi quyn c s dng ti nguyn ti cc node . Ngoi ra n cng c s dng quyt nh xem mt phin (dng lu lng) no c th c u tin hn phin khc hay khng

2.4.3 Giao thc BGP Giao thc cng ng bin cng c tng cng h tr vic phn b nhn. Trong phn ny chng ta ch tng kt ngn gn cc chnh trong cc bn tho lin quan n cng vic ny BGP c s dng phn b mt tuyn ng no n cng c th c s dng phn b mt nhn c rng buc vi tuyn ng . Thng tin rang buc nhn ca mt tuyn ng no c mng cng vi bn tin Update BGP, bn tin ny dng phn b tuyn ng Cc hot ng BGP kh ging vi hot ng ngn xp nhn MPLS thng thng. Chng hn, nu router A bn ngoi cn gi mt gi ti ch D v nu chng k tip BGP ca A l mt router B bn ngoi v nu B rng buc nhn L vi D; lc u tin A s t nhn L vo ngn xp nhn ca gi, sau n s dng IGP tm chng k tip ti B - gi l C. Nu C phn b cho A mt nhn MPLS, th A c th t nhn ny ln ngn xp nhn ca gi v sau gi gi ti C Nu mt tp cc node BGP ang hon i cc thng tin nh tuyn qua mt b phn hi thng tin nh tuyn, lc nu phn b nhn c mng cng vi phn b thng tin nh tuyn, b phn hi thng tin nh tuyn cng c th phn b nhn. iu ny ci thin ng k kh nng m rng mng

Phn b nhn c th c mang cng trong bn tin Update BGP thng qua m rng a giao thc BGP-4 (xem RFC 2283). Lc ny, nhn c m ha vo trong trng thuc tnh NLRI, v trng SAFI(Subsequent Address Family Identifier) ch ra rng NLRI cha mt nhn. Mt node BGP c th khng s dng BGP gi nhn ti mt i tng ngang cp BGP khc, tr khi i tng ngang cp BGP ch ra rng n c th x l cc bn tin Update vi trng SAFI c xc nh (thng qua tho thun kh nng BGP) . Ngoi vic s dng BGP vi vic phn b nhn, n cng ng vai tr quan trng trong cc mng ring o. Tng Kt Chng : Chng 2 a ra mt cch nhn khi qut v MPLS. Vic tm hiu MPLS bao gm tm hiu v khi nim MPLS, phng thc hot ng ca MPLS v cc thnh phn trong MPLS.

KT LUN
Qua mt thi gian hc tp v tm hiu ti khoa Cng Ngh in T /Truyn Thng i hc Cng Ngh Thng Tin-Truyn Thng c s ging dy v gip tn tnh ca cc thy c gio. n nay em kt thc kha hc v nhn ti tt nghip. Vi s gip tn tnh ca c gio Nguyn Th Ngn, cc thy gio c gio trong khoa CNDT-TT v c gng ca bn thn em hon thnh n T nhng kt qu t c, bn n ny c th i su v tip tc nghin cu chi tit hn v cc gii php, m hnh mng quy hoch a ra gii php khai thc v xy dng mng hiu qu hn Do thi gian nghin cu cha di v nhn thc cn nng cn chc chn khng trnh khi nhng thiu st, em xin trn trng cm n v tip thu mi kin ng gp, su cha ca cc Thy c gio v cc bn em c th tip tc hon thin nghin cu v m rng ti ny mt cch ton din.

Em xin chn thnh cm n !

Sinh Vin: Hong Ngc Thnh

Thut Ng Vit Tt:

Ti Liu Tham Kho:

1- K Thut Vin Thng ts Nguyn Tin Ban 2- Mng vin thng th h sau - Nguyn Qu Hin 3- Cng ngh chuyn mch nhn a giao thc MPLS - TS. Phng Vn Vn, KS. Mnh Quyt