BI THC HNH V DCH V HSI, MyTV v OptisystemPHN I. C S L THUYT1.HSI1.1 Tng quan v dch v HSIHSI High Speed Internet l dch v truy cp internet tc cao c nh, cc li ch do internet mang li cho con ngi l rt ln. Thng qua internet ta c th lt web, xem phim, ca nhac, o to trc tuyn, y t t xa, camera IP .....Cc cng ngh s dng truy nhp dch v HSI bao gm: ADSL 2+, VDSL 2, Fast Ethernet (Truy nhp trn cp quang FTTH), xPON (cng ngh mng quang th ng) , TDM ( Thng c s dng cho dch v internet trc tip ).Ty theo cng ngh truy nhp m tc truy nhp c khc nhau, vd: tc down/up ln nht i vi dch v ADSL 2+ l 24M/1M, VDSL 2 l 100M/100M, GPON l 2,5G/1G, v dch v internet trc tip da trn cng ngh TDM l 2M/2M.1.2 Cc giao thc ch yu c s dng trong dch v HSIHTTP: Hyper Text Transfer Protocol: l giao thc thuc lp ng dng dng trao i thng tin gia my ch cung cp dch v web- web servser v cc my s dng dch v web- web client.DNS: Domain Name System: L giao thc c s dng khi truy cp internet, n c nhim v phn gii a ch URL- www.dantri.com.vn thnh a ch IP-123.30.53.12.B giao thc TCP/IP: Transmission Coltrol Protocol/Internet Protocol l b giao thc dng truyn ti thng tin trong mng internet.B giao thc PPP/PPPoE: c s dng thit lp kt ni gia Modem vi mng internet, kt qu l modem c BRAS cung cp cho a ch IP public dng truy nhp internet.1.3 B giao thc PPP/PPPoE

Phin PPPoE: c thit lp trc dng ng gi s liu phin ppp trong khung ethernet, kt qu l modem v bras bit c a ch MAC ca nhau v ID phin c thit lp. N bao gm cc bn tin PADI, PADO, PADR, PADS, PADT.Phin PPP: c thit lp sau phin PPPoE, bao gm cc pha sau: Pha thit lp: LCP thit lp, iu chnh cu hnh, hy b lin kt. Kt thc bng cc bn tin ACK. Pha xc thc: c thc hin sau pha thit lp, xc thc username v password Pha mng: c thc hin sau pha xc thc, thit lp, iu chnh cu hnh, hy b vic truyn s liu ca giao thc lp mng IP. Kt thc bng bn tin ACK cung cp a ch IP cho modem Pha kt thc: c thc hin khi ngt kt ni, yu cu c a ra c th t modem hoc t BRAS, cc bn tin termination LCP, PADT

1.4 Cc thnh phn chnh trong mng cung cp dch v HSIModem: ng vai tr cng kt ni ti internet cho cc my tnh thuc mng LAN pha khch hng, ty theo cch truy nhp mng m c cc loi modem ADSL, FTTH. Thc hin phin kt ni PPP/PPPoE ti BRAS, kt qu nhn c a ch IP public do BRAS cung cp vo internet.IP DSLAM, Switch L2: ng vai tr nh mt thit b mng lp 2 switch trn mng nhm tp trung lu lng, cc thu bao truy cp internet. Vi cng ngh truy nhp xDSL (dch v ADSL, VDSL ) dng IP DSLAM, vi cng ngh truy nhp Ethernet ( Dch v FTTH- Fiber To The Home) dng Switch L2 c cc cng truy nhp quang. Cc IP DSLAM, Switch L2 kt ni n BRAS theo cc VLAN thng qua mng truyn ti MAN EMng truyn ti MAN E: Da trn cng ngh EoMPLS, to cc ng kt ni lp 2 VLL(Virtual Leased Line), ni IP DSLAM, Switch L2 ti BRAS.Bras v Radius Server: ng vai tr xc thc username v password ca thu bao s dng dch v internet, tnh cc ngoi ra BRAS cung cp a ch IP public cho modem v c chc nng nh tuyn ra mi trng Internet. Cc bc thit lp v s dng dch v: Nh cung cp dch v khai bo Account thu bao bao gm cc thng s: username, password, cc tham s v cng kt ni trn IP DSLAM, L2 Switch, tc truy nhp thng qua Webserver. Sau c s d liu xc thc thu bao c chuyn n Server database LDAP Thit lp ng truyn vt l gia MODEM v IP DSLAM hoc L2 Switch: cp ng hoc cp quang. Cu hnh MODEM, thit lp phin kt ni PPP/PPPoE ti BRAS xc thc, BRAS hi RADIUS, RADIUS hi LDAP. Nu xc thc thnh cng BRAS cung cp 01 a ch IP Public cho MODEM. S dng dch v, cc my tnh trong mng LAN ca khch hng vo c Internet2. MyTV2.1 Tng quan v IPTVIPTV (Internet Protocol TV) - l mng truyn hnh s dng CSHT truyn ti IP. Cc user c th thng qua my vi tnh PC hoc my thu hnh ph thng cng vi hp phi ghp Set-top-box (STB) s dng dch v IPTV.IPTV bao gm 3 dch v chnh l Truyn hnh qung b - Broadcast TV (BTV), Truyn hnh theo yu cu Video on Demand (VoD) v nhm dch v tng tc nh truyn thanh (Broadcast Radio), tr chi trc tuyn (Game Online), Thng tin (Information), cc dch v chia s a phng tin (Media Sharing), dch v lu tr (usage data), dch v qung coHin nay trn mng c 1 s nh cung cp dch v IPTV nh VNPT (MyTV), Viettel (NetTV), FPT (iTV), VTCIPTV c th truyn khai trn mng vin thng IP cng nh trn mng truyn hnh cp HFC, tuy nhin trong khun kh bi thc hnh ny s tp trung vo tm hiu v dch v MyTV do VNPT cung cp (c trin khai trn mng vin thng IP ca VNPT).2.2 Cu trc mng cung cp dch v MyTV

Hnh 1 Cu trc tng qut mng cung cp dch v MyTVMng truy nhp:pha ngi dng s dng cc thit b nhModem (ADSL hoc FTTx), Set-top-box (STB).Mng truyn ti IP: i vi cc knh truyn hnh qung b (BTV) trn mng ny s sdng k thutnh tuyn Multicast cp pht ni dung t ngun (source) n cc ngi dng IPTV (ch) vic s dng ti nguyn mng truyn ti hiu qu. i vi dch v VoD th mt kt niim-im sc thit lp gia ngi s dng v ngun pht ni dung.Mng cung cp ni dung: Phn mng ny bao gm chc nng thu thp ni dung thng tin, lu tr v pht ccni dung nyn thu bao. Ngun ni dung c m ha trc khi cung cp ti cc ngi dng u cui.2.3 C ch hot ng ca MyTV dch v MyTV c th hot ng cn phi tri qua cc bc sau y: STB nhn c IP chnh xc t DHCP Server trong mng cung cp ni dung. Sau khi nhn c a ch IP chnh xc STB xc thc thnh cng vi EPG Server (Electronic Program Guides) trong mng cung cp ni dung. Sau STB xc thc thnh cng, dch v MyTV c s dng bnh thng.Nh vy MyTV hot ng bnh thng m bo nh sau: CPE c cu hnh chnh xc STB thng vi DHCP Server trong mng cung cp ni dung v nhn c a ch IP chnh xc. STB c cu hnh chnh xc c th xc thc thnh cng.2.4 Nguyn l hot ng cc dch v c bn ca MyTVNguyn l hot ng ca dch v BTV (LiveTV) : Dch v LiveTV hin ti do VNPT cung cp s dng giao thc IGMPv2 ly ngun t BTV Server. Flow dch v : STB gi gi tin IGMP Report / Join Group (sau lung Multicast v STB). IGMP Router ( y l DSLAM hoc L2SW c tnh nng IGMP Snooping) gi u n gi tin IGMP Query / STB nhn c s tr li bng gi tin IGMP Membership Report. STB gi gi tin IGMP Report / Leave Group.Dch v VoD hin ti do VNPT cung cp s dng giao thc RTSP ly ngun t VoD Server. Flow dch v (STB gi cc gi tin RTSP thit lp phin kt ni v VoD Server tr li bng cc gi tin RTSP REPLY 200 OK) : STB gi gi tin RTSP DESCRIBE. Sau khi nhn c phn hi t VoD Server, STB gi gi tin RTSP SETUP. Sau , STB gi gi tin RTSP PLAY khi bt u xem phim (C lung Unicast v STB). STB gi gi tin RTSP PAUSE khi tm dng xem phim. STB gi gi tin RTSP TEARDOWN khi kt thc xem phim.3. Optisystem3.1 Gii thiu chungCng vi s bng n v nhu cu thng tin, cc h thng thng tin quang ngy cng tr nn phc tp. phn tich, thit k cc h thng ny bt buc phi s dng cc cng c m phng OptiSystem l phn mm m phng h thng thng tin quang. Phn mm ny c kh nng thit k, o kim tra v thc hin ti u ha rt nhiu loi tuyn thng tin quang, da trn kh nng m hnh ha cc h thng thng tin quang trong thc t. Bn cnh , phn mm ny cng c th d dng m rng do ngi s dng c th a thm cc phn t t nh ngha vo.Phn mm c giao din thn thin, kh nng hin th trc quan.3.2 Tng quan h thng WDMGhp knh theo bc sng WDM (Wavelength Devision Multiplexing) l cng ngh trong mt si quang ng thi truyn dn nhiu bc sng tn hiu quang. u pht, nhiu tn hiu quang c bc sng khc nhau c t hp li (ghp knh) truyn i trn mt si quang. u thu, tn hiu t hp c phn gii ra (tch knh), khi phc li tn hiu gc ri a vo cc u cui khc nhau.S tng qut

Phn loi h thng

Cc phn t c bn trong h thng WDM B pht quang: Cc ngun quang c bn s dng trong h thng thng tin cp si quang c th l Diode Laser (LD) hoc Diode pht quang (LED). B thu quang: Phn thu quang gm cc b tch sng quang, knh tuyn tnh v knh phc hi. N tip nhn tn hiu quang, tch ly tn hiu thu c t pha pht, bin i thnh tn hiu in theo yu cu c th. Trong phn ny thng s dng cc photodiode PIN hoc APD. Si quang: L si n mode c s dng ph bin trn mng li vin thng nhiu nc hin nay. N c th lm vic 2 ca s: Ca s 1310nm, ca s 1550nm. Si quang G655 thch hp cho h thng DWDM, lm tng dung lng truyn dn. B tch/ghp bc sng (OMUX/ODEMUX): B ghp/tch knh bc sng, cng vi v kt ni cho quang, l thit b quan trng nht cu thnh nn h thng WDM. B tch/ghp knh thc hin ghp tch tn hiu cc bc sng khc nhau. B xen/r bc sng (OADM): OADM c cu hnh xen/ rt mt s knh bc sng,cc knh bc sng cn li c cu hnh cho i xuyn qua. B ni cho quang (OXC) B khuch i quang (OA) B chuyn i bc sngCc tham s c bn ca ghp knh quang theo bc sng Suy hao xen: c xc nh l lng cng sut tn hao trong tuyn truyn dn quang do cc im ghp ni cc thit b WDM vi si v suy hao do bn thn cc thit b ghp gy ra. V vy, trong thc t thit k phi tnh cho vi dB mi u. Xuyn knh: Xuyn knh l s c mt ca mt knh ny trong knh k cn lm tng nn nhiu v gim t s tn hiu nhiu ca knh ang xt. rng knh: Hin nay trong h thng vin thng dng si quang thng s dng bc sng 1550nm v cc b khuch i EDFA. Bng thng cc i ca b khuch i si pha tp EDFA khon 30nm. Nu ta mun xp khong 16 knh trong di bc sng ny th rng gia cc knh l 30nm/16 knh hay 1,875nm. nh hng ca cc hiu ng phi tuyn: Trong h thng thng tin quang, cc hiu ng phi tuyn s xy ra khi cng sut tn hiu trong si quang vt qu mt gii hn ca h thng WDM th mc cng sut ny thp hn nhiu so vi cc h thng n knh.PHN II. KT QU THC HNH1 1. Kt qu thc hnh bi HSI2. Kt qu bt gi tin dch v Live TV2.1 Bn gi tin Discover / Offer / Request / ACK

Khi khi ng chng trnh MyTV, h thng sau khi cu hnh xin a ch IP ng t DHCP server (Obtain an IP Address Automatically) th ln u tin tham gia h thng mng n s dng tn hiu Broardcast (255.255.255.255) pht ra gi tin DHCP Discover vi di bn tin l 590 bytes. Ni dung gi tin yu cu cung cp cc thng s v a ch IP cho chnh mnh t DHCP server m Client ny s s dng khi tham gia vo h thng mng.DHCP server sau khi nhn c gi tin Discover t Client,n s tr li cho Client bng cch Broadcast gi tin DHCP Offer. Gi tin ny xc nhn n l DHCP Server v a li ngh s cp cho Client nhng thng s IP nht nh (10.41.242.222).Nu nhn c gi tin DHCP Offer, Client Broardcast tr ngc cho Server gi tin DHCP Request xc nhn thng tin v mnh v yu cu cp cc thng s IP cho mnh.Do trong h thng mng c th c nhiu DHCP Server nn khi Broadcast gi tin DHCP Request Client,cng s km theo nhng thng s nhn bit v Server m mnh chn xin IP. T cc DHCP khc s rt li gi tin Offer v dnh cho Client khc.Nhn c li chp nhn t my Client,DHCP Server ngay lp tc gi gi tin DHCP ACK (Acknowledgment).y chnh l nhng thng s cu hnh a ch IP m DHCP Server ngh vi Client ngay t u.DHCP Server lc ny cng c th gi gi tin DHCP ACK nhng cng c th gi gi tin DHCP NAK (Negative Acknowledgment), nu li ngh lc u khng chnh xc na hoc thng s IP c my tnh khc s dng.V d nhin Client phi bt du li qui trnh xin cp IP.2.2 Bn tin chuyn knh

Khi ta m mt knh bt k th h thng (client 10.41.242.222) gi bn tin ti sever (224.0.0.2) leave group sau client gi bn tin ti sever (232.84.1.28) bng bn tin Join Group vi di 60 bytes.3. Kt qu bt gi tin dch v VoD3.1 Bn tin UDPHnh chp mn hnh Wireshark bt c duy nht 1 lung UDP.

VoD l dch v thi gian thc v hot ng trn giao thc UDP.Nh ta thy, sever (232.84.1.204) lin tc gi bn tin UDP v s dng dch v VoD.3.2 Bn tin khi dng phim, xem li phim v kt thc phim

RTSP (Real Time Streaming Protocol):RTSP c xem la giao thc chun trong k ngh multimedia streaming, RTSP la dang application-level protocol, giao thc nay lam vic bng cach be nho cac goi d liu tuy theo tc bng thng cho phep gia client va server. Khi ma client a nhn va u lng d liu thi player se giai nen, play goi d liu u ri sau o tip tuc download goi d liu tip theo va tip tuc play goi d liu k ti va c tip tuc nh vy. Giao thc RTSP gi y a c th gii hoa va ap dung trong hu ht cac ng dung streaming. RTSP cung co nhng t im nh MMS la h tr cac tinh nng nh fast-forwarding, rewinding, pause, start hay stop. i vi mt s media file khng th streaming bng giao thc chun cua Microsoft Media Server chng han nh cac dang digital media content nh MPEG-4, MPEG hay AVI, RTSP se giai quyt vn nay.Khi dng phim, client (10.41.242.222) gi bn tin ti sever (172.16.30.12) vi bn tin RTSP vi ni dung Pause.Sau khi dng vi bn tin pause, khi bt li phim th client (10.41.242.222) gi bn tin ti sever (172.16.30.12) vi ni dung play.Vi bn tin khi kt thc phim, client (10.41.242.222) gi ti sever (172.16.30.12) bn tin RTSP vi ni dung TEARDOWN.

4. S dng phn mm Optisystem thit k h thng thng tin quang WDMBi 1Xy dng b pht quang laser diode s dng k thut iu bin trc tip v kho st c tnh.Xy dng b pht quang laser diode s dng k thut iu bin ngoi dng b iu ch Mach-Zehnder.a. Kho st c tnh b pht quang LD s dng iu ch trc tip-Xy dng b pht theo s khi

-Thit lp cc tham s c bn cho cc khi hot ng ti tc 2.5 Gbit/s, di chui bit bng 32 bit, s mu 512 mu/mi bt

-Kim tra v hiu chnh cc tham s dng kch thch trc khi chy m phngCng sut ca laser l 10 dbm,tn s f=193.1 THz-Chy m phng v thu thp kt quDng ngng 33.45723247941mA Dng nh thin(bias) (20 mA) nh hn dng ngng ca laserPh quang ca tn hiu quang

Dng sng ca tn hiu quang v dng sng tn hiu in kch thch

Xung quang sai khc nhiu so vi xung in kch thch do nhiu bit li,BER lnChirp tn

Chirp dch chuyn nhiu so vi tn hiu quang voBiu mt

Biu mt xu,nhiu nhiu,mt khng r rng do BER ln Dng nh thin (bias)(40 mA) ln hn dng ngng ca laser Ph quangPh m rng do c chirp tn,chirp tn cng ln th ph m rng cng lnDng sng tn hiu quang iu ch v dng sng tn hiu in kch thch

Dng sng ca tn hiu quang tng i n nh v gn ging vi dng sng ca tn hiu in kch thch do bit li t hn vi trng hp dng bias nh hn dng ngng. Biu mtMt m to,r,t nhiu hn so vi trng hp dng bias nh hn dng ngng ca laser.b.Kho st c tnh b pht quang LD s dng iu ch ngoi-Xy dng b pht quang

-Thit lp cc tham s c bn cho cc khi hot ng ti tc 2.5Gbit/s, di chui bit bng 32bit,s mu 32 mu/mi bt

-Kim tra v hiu chnh cc tham s b iu ch MZM trc khi chy m phng

-Chy m phng v thu thp kt qu Trng hp h s i xng bng -1Ph quang

Dng sng tn hiu quang iu bin v dng sng tn hiu in kch thch

Dng sng tn hiu quang iu ch v dng sng tn hiu in kch thch ging nhauChirp tn

Chirp tn c xy ra lm m rng ph,dch chuyn nhiu so vi dng sng tn hiu quang iu ch.Biu mt

Trng hp h s i xng bng 0Ph quang

Dng sng ca tn hiu quang iu bin v dng sng ca tn hiu in kch thch

Dng sng ca 2 tn hiu ging nhauChirp tn

Chirp tn trng vi dng sng ca tn hiu quang iu chBiu mt

Mt m to,r,t nhiu.c. So snh kt qu phn tch trong hai trng hp iu ch trc tip v iu ch ngoi-Biu mt ca trng hp iu ch ngoi p hn, m to hn so vi iu ch trc tip trong c 2 trng hp h s i xng -1 v 0.-Chirp tn do laser gy ra trong trng hp iu ch trc tip nh hng nghim trng ti h thng truyn dn,chirp tn trong trng hp iu ch ngoi c th c trit tiu.-Dng sng tn hiu quang iu bin trong iu ch trc tip th khng n nh, c nhng khong b t bin cn trong trng hp iu ch ngoi th do laser CW c sng pht lin tc nn tn hiu qua b iu ch MZM lin tc nn dng sng ca tn hiu quang iu ch n nh hn,chirp tn t hn.Bi 2Xy dng b thu quang s dng PIN v kho st nhy thu.Xy dng b thu quang s dng APD v kho st nhy thu.a. Kho st nhy b thu quang s dng PIN -Xy dng b thu quang s dng diode thu quang PIN theo s khi

a.1 Cc khi trong s hot ng ti cc tc 2.5Gbit/s, di chui bit bng 128,s mu 64 mu/bit-Thit lp cc tham s

-Kim tra v hiu chnh cc tham s suy hao ca b suy hao trc khi chy m phng

-S dng ch qut qut gi tr suy hao(qut 21-25db)

Suy hao tng,BER tng.Do BER qu nh khong (21dB)nn khi biu din th gn nh bng 0.-V ng cong BER l hm cng sut thu

T vic qut tham s,ta thy c b nhy thu ti mc BER= l -24.4637 dBm.a.2 Thit lp cc tham s c bn cho cc khi trong s hot ng ti tc 10Gbit/s, di chui bit bng 128 bit,s mu 64 mu/bit-Thit lp cc tham s

-Kim tra v hiu chnh cc tham s suy hao ca b suy hao trc khi chy m phng

-Chy m phng v thu thp kt qu ti cc gi tr suy hao khc nhau

Suy hao tng,BER tng. Ti cc gi tr suy hao thp th BER rt nh BER biu din st trc ta ,gn nh bng 0.-V ng cong BER l hm ca cng sut thu v xc nh nhy ca b thu ti mc BER=

T vic cc gi tr trn ta c th xc nh c nhy b thu ti mc BER= l -21.569 dBmSau khi kho st b thu quang s dng PIN ti 2 tc 10Gbit/s v 2,5Gbit/s th ta thy rng nhy b thu ti mc BER=,suy hao 20 dB th i vi trng hp h thng ti tc 10Gbit/s gim hn nhiu so vi nhy b thu trong trng hp h thng hot ng tc 2.5Gbit/s. Vi b thu PIN, thng l nhiu nhit nn ta c th tnh theo cng thc rt gn . Ta thy ph thuc khng ch vo cc tham s ca b thu m cn ph thuc vo c tc bit,tham s ca b thu quang. Nhn chung, =B/2, v th khi b thu hot ng trong gii hn nhiu nhit, s tng theo v iu c ngh l nhy thu s gim khi tc bit tng. Mt khc,ta cng thy rng cc gi tr nhiu n, nhiu nhit ca b thu cng ph thuc vo tham s ca b thu (t l thun).T , khi B tng th cng tng, tc l nhiu cng tng,BER tng.b. Kho st b thu quang s dng APD-Xy dng b thu quang s dng diode thu quang APD theo s khi

-Thit lp cc tham s c bn cho cc khi trong s h thngb.1 Cc khi trong s hot ng ti tc 2.5Gbit/s, di chui bit bng 128 bit, s mu 64 mu/bit.

-Kim tra v hiu chnh cc tham s suy hao ca b suy hao trc khi chy m phng

-Chy m phng v thu thp kt qu ti cc gi tr suy hao khc nhau

Suy hao tng BER tng, ti cc gi tr suy hao thp gi tr BER rt nh,gn nh bng 0.-BER l hm ca cng sut thu v xc nh nhy

T vic chy m phng trn ta xc nh c nhy ca my thu ti BER=l -28.8321 dBm.b.2 Thit lp cc tham s c bn cho cc khi ca h thng hot ng ti tc 10Gbit/s, di chui bit 128 bit, s mu 64 mu/bit.-Thit lp cc tham s c bn

-Kim tra v hiu chnh cc tham s suy hao ca b suy hao trc khi chy m phng

-Chy m phng v thu thp cc kt qu ti cc gi tr suy hao khc nhau

Suy hao tng BER tng,ti cc gi tr suy hao thp BER nh,gn nh bng 0.-V ng cong BER l hm ca cng sut thu v xc nh nhy ca my thu

T kt qu chy m phng trn ta xc nh c nhy ca my thu ti BER= l -25.7795 dBm.Sau khi kho st b thu quang s dng APD ti 2 tc 10Gbit/s v 2,5Gbit/s th ta thy rng nhy b thu ti mc BER=,suy hao 20 dB i vi trng hp h thng ti tc 10Gbit/s gim nhiu so vi nhy b thu trong trng hp h thng hot ng tc 2.5Gbit/s., ph thuc vo tham s ca ca b thu quang.Nhn chung,, v th khi b thu hot ng trong gii hn nhiu nhit, s tng tuyn tnh theo B, v iu c ngha l nhy thu gim khi tng tc bit. Ta thy rng, cc gi tr nhiu n, nhiu nhit ca b thu ph thuc vo tham s ca b thu(t l thun).T ,khi B tng th tng, tc l nhiu tng do BER tng.Bi 3Xy dng tuyn truyn dn si quang s dng si n mode chun v kho st c tnh.Xy dng tuyn truyn dn si quang c s dng si b tn sc v kho st c tnh.a.Kho st tuyn truyn dn si quang s dng si n mode chun(SSMF)-Xy dng tuyn truyn dn si quang theo s

-Thit lp cc tham s ph hp cho cc khiCc khi trong h thng hot ng ti tc 2.5Gbit/s, c di chui bit bng 128bit, s mu l 64 mu/bit.Chiu di si SSMF mi chng l 80km, b khuch i EDFA c h s nhiu NF=5dB.

-Kim tra v hiu chnh tham s vng lp trc khi chy m phng

-Quan st biu mt

Xc nh tham s OSNR qua ph quang

T vic phn tch ph xc nh c OSNR=-9.84573-(-34.2713)=24.42557dBm.-Chy m phng ti cc khong cch tuyn truyn dn khc nhau

-V ng cong BER v tham s OSNR l hm ca khong cch truyn dn v xc nh gii hn khong cch ca h thng ti mc BER=.

Chiu di si SSMF=80km vi 10 vng lp=>gii hn khong cch ca h thng ti mc BER=.b.Kho st tuyn truyn dn si quang c s dng si b tn sc(DCF)-Xy dng tuyn truyn dn si quang

-Thit lp cc tham s ph hp cho cc khi ca h thng di chui bit bng 128bit,s mu 64 mu/bit.Chiu di si SSMF mi chng l 80km, chiu di si DCF l 20km cho php b tn sc trn mi chng.Si DCF c h s suy hao 0.5dB/km v din tch hiu dng l 20.B khuch i EDFA c h s nhiu NF=5dB.

Tc ca h thng hot ng l 2.5Gbit/s

-Kim tra hiu chnh tham s vng lp trc khi chy m phng

-Quan st biu mt

-Xc nh OSNR

Tham s OSNR=-3.22636-(-36.7542)=33.52784 dBm-Chy m phng v thu thp kt qu ti cc khong cch truyn dn khc nhau

Gii hn khong cch ca h thng t BER= l100x16=160 km Tc hot ng ca h thng l 10Gbit/s

-Quan st biu mt

-Xc nh OSNR da vo ph quang

OSNR=-3.78668-(-33.1425)=29.35582 dBm-Chy m phng v thu thp kt qu ti cc khong cch truyn dn khc nhau

Gii hn khong cch ca h thng ti mc BER= l 100x1=100 Kmc.Thu thp kt quBi 4Xy dng h thng truyn dn quang WDM v kho st hiu nng ca h thnga.Kho st hiu nng h thng truyn dn quang WDM v xc nh cng sut pht ti u-Xy dng h thng truyn dn WDM theo s

-Chy m phng v thu thp kt qu ti cc mc cng sut pht khc nhau

Knh ti nht l knh 2 c BER ln nht F=193.15 THzMc cng sut pht ti u P=-3.33333 dBmKnh tt nht l knh 1 c BER nh nht F=193.1 THzb.Kho st hiu nng h thng truyn dn quang WDM v xc nh gii hn khong cch truyn dn -Chy m phng v thu thp kt qu ti cc khong cch tuyn truyn dn khc nhau(thay i s vng lp)

-V ng cong BER l hm ca khong cch truyn dn ca knh tt nht, xc nh gii hn khong cch v OSNR ca h thng ti BER= ti tc 10Gbits/s.Da vo phn a, ta thy knh tt nht l knh 1 vi tn s F=193.1 THz.

-V ng cong BER l hm ca khong cch truyn dn ca knh ti nht, xc nh gii hn khong cch v OSRN ca h thng ti BER= ti tc 10Gbits/s.-V ng cong BER l hm ca khong cch truyn dn ca knh tt nht, xc nh gii hn khong cch v OSRN ca h thng ti BER= ti tc 20Gbits/s.-V ng cong BER l hm ca khong cch truyn dn ca knh ti nht, xc nh gii hn khong cch v OSRN ca h thng ti BER= ti tc 20Gbits/s.c.Nhn xt kt qu nhn c

Title

PPPoEClient

PPPoEServer

PADI

PADO

PADI

PADO

PADR

PADS

Cc bn tin trao iPhin PPPoE

Cc bn tin trao iPhin PPP

Configuration Request

Configuration Request

Configuration ACK

Configuration ACK

Cc bn tin trao iPha thit lp LCP

Challenge

Response

Success

Cc bn tin trao iPha xc thc

Configuration Request

Configuration Request

Configuration Nak

Configuration Request

Configuration Ack

Cc bn tin trao iPha mng IPCPCp pht IP

Termination Request PPP LCP

PADT - PPPoE

Cc bn tin trao iPha kt thc kt ni