Mạng thế hệ sau và tiến trình chuyển đổi

Mang the he sau la mot mang truyen tai thong tin tren c o so chuyen mach goi, cung cap da dich vu, da phuong tien, h6 trg da giao thuc, mcf rong bang thong cho tat ca cac loai hinh dich

ThS N G O MY HANH

the he sau

va him triiilijluiyBii ioi

NHA XUAT BAN BlfU OIEN

HA NQI - 2006

Ma s6: HV 06 HM 06

ton noi onu

Hien nay, xu huong hoi tu mang vi6n thong, mang truyen dir lieu va mang may tinh dang d iin ra manh me tren the gicfi Mang vidn thong the he sau (NGN - Next Generation Network) ra doi d6 dap ling xu huong do Mang the he sau la mot mang truyen tai thong tin tren c o so chuyen mach goi, cung cap da dich vu, da phuong tien, h6 trg da giao thuc, mcf rong bang thong cho tat ca cac loai hinh dich vu, dam bao chat luong QoS tren c o so cung cap cac dich vu thoi gian thuc Khi mang the he sau ra doi thi cac hang cung cap thiet bi vidn thong lcfn tren the gidri cung nhanh chong d6 xuat cac mo hinh khac nhau Thuc chat, thuat ngu NGN duoc de cap cung chi mang tinh dinh huong chien luoc nham tien toi hoi tu giura vidn thong va cong nghe thong tin voi cac loai hinh dich vu true tuyen ngay cang tro len pho thong hon, don gian hon

va kinh te hon Vi the, xu huong tien len NGN la tat yeu nhirng van

d i dat ra cho m6i mang cu the? de tien len NGN la chon lua cac buoc di va tien trinh chuyen doi nhu the nao d i toi uu VI vay, \ie c xuat ban mot cuon sach gidri thieu ve N G N cung nh u tien trinh dei chuyen doi mot m ang cu the len NGN la rat can thiet De dap ung nhu cau nay, N ha xuat ban Buu dien cho xuat ban cuon sach

"Mang the he sau va tien trin h c h u ye n doi'' do ThS Ngo My Hanh

bien soan

Noi dung cuon sach gom 5 chuong:

Clufcmg 1 Tong quan v& mang the he sau

C huong 2 Cau true mang the he sau

Chuong 3 Gioi thieu ve mang vien thong cua mot so nirdc

trong khu vuc

C huong 4 M ang duong true cua Viet N am va tien trinh chuyen

doi sang m ang the he sau

C huong 5 Cac dich vu m ang the he sau

Hy vong cuon sach se la tai lieu tham khao huu l'ch cho cac chuyen gia, cac can bo va ky thuat vien cong tac trong llnh virc vi6n thong N goai ra, tai lieu nay cung se dap ung dupe nhu cau tim hieu va ap dun g cong nghe m 6i cua cac giang vien, sinh vien cac trudng Dai hoc, Cao dang va cac co so dao tao chuyen nganh Vi6n thong

Cong nghe N G N va viec chuyen d6i mang hien nay sang mang the he sau la van d6 con moi me, cuon sach nay se khong tranh khoi thieu sot, Nha xuat ban Buu dien mong nhan duoc moi y kien dong gop cua ban doc

Moi y kien gop y cua quy vi va ban doc xin gui ve Nha xuat ban Buu dien - 18 N g u y in Du, Ha Noi

Tran trong cam an./.

H a N oi, thdng 8 ndm 2006

NHA XUAT BAN B IX DIEN

Chtfdng 1

T<)NG QUflH VE M0NG THE HE MCI

1.1 M A N G V lfcN T H O N G H I$ N TAI

1.1.1 K hai niem ve m ang viC*n thong

M ang vidn thong la phuong tien truyen dua thong tin tu diiu phat toi dau thu Mang co nhiem vu cung cap cac dich vu cho khach hang.Mang vien thong bao gom cac thanh phan chi'nh: thiet bi chuyen mach, thiet bi truyen dan moi trudng truyen va thiet bi dau cuoi

Hinh 1.1: Cac thanh phan chinh cua mang vien thong

- Thiet bi chuyen mach gom co tong dai noi hat va tong dai chuyen tiep Cac thue bao dupe noi vao tong dai noi hat va t6ng dai noi hat dupe noi vao tong dai chuyen tiep Nhd cac thiet bi chuyen mach ma duong truyen d in dupe dung chung va mang co the dupe sir dung mot each kinh te

8 Mang the he sau va tien trinh chuyen doi

- Thiet bi truyen dan dung de noi thiet bi dau cuoi vdi tong dai

hay giua cac tong dai de thuc hien viec truyen dua cac tin hieu dien Thiet bi truyen d i n chia lam hai loai: thiet bi truyen dan phfa thue bao va thiet bi truyen d i n cap quang Thiet bi truyen d in phia thue bao dung moi trudng truyen thudng la cap kirn loai tuv nhien

co mot so trudng hop moi trudng truyen la cap quang hoac vo tuyen

- Moi trudng truyen bao gom truyen huu tuyen va vo tuyen Truyen huu tuyen bao gom cap kim loai, cap quang Truyen vo tuyen bao gom vi ba, ve tinh

- Thiet bi d iu cuoi cho m ang thoai truydn thong gom may dien

thoai, m ay Fax, may vi trnh, tong dai nhanh rieng (PABX)

M ang vien thong cung co the dupe dinh nghla nhu sau: Mang vien thong la m ot he thong gom cac nut chuyen mach dupe noi voi nhau bang cac dudng truyen d in Nut dupe phan thanh nhieu cap va ket hop vdi cac dudng truyen d in tao thanh cac ca'p mang khac nhau

t

T E Transit Exchange - Tong dai chuyen tiep quoc gia

H LE Host Local Exchange -Tong dai noi hat

R L E : Remote Local Exchange - Tong dai xa (Tong dai ve tinh) Sub: Subscriber - Thue bao

Hinh 1.2: Cau hinh mang c o ban

ChM ng 1: TSng quart ve mang the he sau 9

M ang vi£n thong hien nay dirge chia thanh nhieu loai Do la mang mdc liroi, mang sao, mang long hop, mang vong km va mang thang Cac loai mang nay co uu diem va nhuoc diem khac nhau de phu hop vdi cac dac diem cua timg vung dia ly (trung tam, hai dao, bien gidi, ) hay vung luu luofng (luu thoai cao, thap, )

M ang vien thong hien nay duoc phan cap n hu sau:

Tong dai quoc te

Tong dai chuyen tiep quoc gia

Tong dai chuyen tiep noi hat hoac noi tinh

Tong dai noi hat

Tong dai khu vtfc

Hinh 1.3: Cau true mang phan cap

Trong m ang hien nay gom 5 nut:

Nut cap 1: trung tam chuyen mach chuyen tiep quoc te Nut cap 2: trung tam chuyen mach chuyen tiep dudng dai Nut cap 3: trung tam chuyen mach chuye-n tiep noi hat Nut cap 4: trung tam chuyen mach noi hat

Nut cap 5: trung tam chuyen mach tu xa

10 Mang the he sau va tien trinh chuySn doi

1.1.2 C ac dac diem cua m ang vi£n thong hien nay

Cac mang vien thong hien tai co dac diem chung la ton tai mot each rieng le, ung voi moi loai dich vu thong tin lai co ft nhat mot loai m ang vien thong rieng biet de phuc vu dich vu do

- M ang Telex: dung de’ giri cac burc dien dudi dang ky tu da duoc ma hoa bang 5 bit Toe dp truyen rat thap (tu 75 toi 300 bit/s)

- M ang dien thoai cong cong, con goi la mang POTS (Plain Old Telephone Service): 6 day thong tin tieng noi dupe so hoa va chuyen mach 6 he thong chuyen mach dien thoai cong cong PSTN

- M ang truyen so lieu: bao g6m cac m ang chuyen mach goi d6 trao d6i so lieu giura cac m ay tinh dua tren giao thuc cua X.25 va

he thong truyen so lieu chuyen mach kenh dua tren cac giao thucX.21

- Cac tin hieu truyen hinh co the dupe truyen theo ba cach: truy£n bang song vo tuyen, truyen qua he thong m ang truyen hinh cap CATV (Cable Television) bang cap dong true hoac truyen qua

he thong ve tinh hay con goi la truyen hinh true tiep DBS (DirectBroadcast System)

- Trong pham vi co quan, so lieu giua cac may tinh dupe trao doi thong qua mang cuc bo LAN (Local Area Network) ma noi tieng nhat la mang Ethernet, Token Bus va mang vong the bai.Moi mang dupe thiet ke cho cac dich vu rieng biet va khong the sir dung cho cac muc dich khac Vi du ta khong the truyen thoai qua mang chuyen mach goi X.25 vi tre qua m ang nay qua ldn Truoc khi tim hieu m ang vien thong the he sau NGN chung ta

c a n hieu ro su phat trien CLa cac m ang hien tai ma tieu bieu la:

- Xet \ e goc do dich vu th'i gom cac mang sau: mang dien thoai

co dinh mang dien thoai di dong va mang truyen so lieu

Chuong 1: Tong quan ve mang the he sau 11

- Xet ve goc do ky thuat bao gom cac mang chuyen mach, mang truy£n d in mang truy nhap, mang bao hieu va mang d6ng bo

PSTN (Public Sw itchin g Telephone N etwork) la mang chuyen

m ach thoai cong cong PSTN phuc vu thoai va bao g6m hai loai tong dai: tong dai noi hat (cap 5), va tong dai tandem (tong dai chuyen tiep noi hat cap 4) Tcing dai chuyen tiep noi hat dugc noi vao cac tcing dai Toll de giam inure phan cap Phuong phap nang cap cac long dai chuyen tiep la bo sung cho m6i nut mot loi ATM Cac loi ATM se cung cap dich vu bang rong cho thue bao, d6ng thcri hop nhat cac mang so lieu hien nay vao mang chung ISDN Cac icing dai cap 4 va cap 5 la cac tong dai loai Idn Cac tcing clai nay co kien true tap trung cau true phiii mCm va phan cung doc quyen

IS D N (In teg ra ted S ervice D ig ita l N etw ork) la m ang so ti'ch

hop da dich vu ISDN cung cap nhieu loai ung dung thoai va phi thoai trong cung mot mang va xay dung giao tiep ngudi sir dung - mang da dich vu b;\ng mot so gidi han cac ket noi ISDN cung cap nhieu ung dung khae nhau bao gom cac ket noi chuyen mach va khong chuyen mach Cac ket noi chuyen mach cua ISDN bao gom nhieu chuyen m ach thuc, chuyen mach goi va su ket hop cua chung Cac dich vu mdi phai tuong hop voi cac ket noi chuyen mach so 64 kbit/s ISDN phai chua su thong minh de cung cap cho cac dich vu, bao dudng va cac chuc nang quan ly mang, tuy nhien tinh thong minh nay co the khong dii de cho mot vai dich vu mdi

va can dirge tang cudng tir m ang hoac tir sir thong minh thich ung trong cac thiet bi d i u cuoi cua ngudi sir dung Sir dung kien true phan lop la dac trung cua truy xuat ISDN Truy xuat cua ngudi sir dung den ISDN co the khae nhau tuy thuoc vao dich vu yeu cau va tinh trang ISDN cua tirng quoc gia Can thay r in g ISDN dugc sir dung vdi nhieu cau hinh khae nhau tuy theo hien trang m ang vien thong cua tirng quoc gia

12 Mang the he sau va tien trinh chuyen d6t

P S D N (Pu blic S w itch in g D ata N etw ork) la m ang chuyen

mach so lieu cong cong PSDN chu yeu cung cap cac dich vu so lieu Mang PSDN bao gom cac PoP (Point of Presence: di^m hien dien) va cac thiet bi truy nhap tu xa Hien nay PSDN dang phai trien vdi toe do rat nhanh do su bung nd cua dich vu Internet va cac mang rieng ao (Virtual Private Network)

M an g di don g G SM (G lo b a l System f o r M obile Telecom ) la

mang cung cap dich vu thoai tuong tu nhu PSTN nhimg qua dudng truy nhap vo tuven M ang nay chuyen m ach dua tren cong nghe ghep kenh phan chia thdi gian va cong nghe ghep kenh phan chia tan so Cac thanh p h in co ban cua mang nay la bo di£u khien tram goc (BSC * Base Station Controller), tram chuyen tiep goc (BTS - Base Transfer Station), D ang kf dinh vi thudng tru (H LR - Home Location Register), dang kf dinh vi tam tru (V L R - Visitor Location Register) va thue bao di dong (MS- Mobile Subscriber)

Hien nay cac nha cung cap dich vu thu dugc lgi nhuan phin Ion tu cac dich vu nhu kenh thue rieng, chuyen tiep khung, ATM,

va cac dich vu ket noi co ban Tuy nhien xu hudng giam lgi nhuan

tu cac dich vu nay b it buoc cac nha khai thac phai tim dich \xi moi dua tren IP de dam bao lgi nhuan lau dai V PN la mot hudng di cua cac nha khai thac Cac dich vu dua tren n£n IP cung cap ket noi giua mot nhom ngudi sir dung xuyen qua m ang ha tin g cong cong VPN co the dap ung cac nhu cau cua khach hang b in g cac ket noi dang nhieu tdi nhieu (any-to-any), cac ldp da dich vu, cac dich vu gia thanh quan ly thap rieng tu, tich hgp xuyen suot cung vdi cac mang Intranet/Extranet M ot nhom ngudi sir dung trong Intranet va Extranet co the hoat dong thong qua m ang co dinh tuyen IP Cac mang rieng ao co chi phi van hanh thap hon han so vdi m ang rieng tren phuong tien quan ly bang thong va dung luong Hieu mot cach don gian VPN la mot m ang m d rong tu quan nh u mot su lira chon co so ha tang cua m ang W A N VPN co the lien ket ngudi sir

Chuong 1: Tong quart ve mang the he sau 13

dung thuoc mot nhom kin hay giua cac nhom khae nhau VPN dugc dinh nghla b in g mot che do quan ly Cac thue bao VPN co the di chuyein den mot ket noi m6m deo trai dai tir mang cuc bo den m ang hoan chinh Cac thue bao nay co the diing trong cung (Intranet) hoac khae (Extranet) to chuc Tuy nhien can luu y rin g hien nay mang PSTN/ISDN v in dang la mang cung cap cac dich vu dir lieu

1.1.3 S a lirac m ang vi6n th on g V iet Nanj

a C au tru e m ang

De phuc vu cho cac dich vu thong tin nhu thoai, so lieu, fax, telex va cac dich vu khae nhu dien thoai di dong, n h in tin, nen nude ta hien nay ngoai m ang chuyen mach cong cong con co cac

m ang ciia mot so djch vu khae Rieng mang Telex khong ket noi vdi m ang PSTN, con cac m ang khae d£u dugc ket noi vao mang PSTN thong qua cac kenh trung ke hoac cac bo MSU (Main Switch Unit), m ot so khae lai truy nhap vao mang PSTN qua cac kenh thue bao binh thudng, sir dung ky th u at DLC (Digital Loop Carrier), ky thuat truy nhap vo tu y e n ,

Ve ca'u true mang, m ang vi6n thong ciia Viet N am hien nay chia thanh 3 cap: cap quoc te, ca'p quoc gia, ca'p noi tinh/thanh pho.Xet ve khfa canh cac chirc nang ciia cac he thong thiet bi tren

m ang thl mang v iin thong bao gom: mang chuyen mach, mang truy nhap, mang tru y in d i n va cac mang chute nang

b M a n g chuyen m ach

M ang chuyen m ach co 4 cap (dua tren cac cap tdng dai chuyen mach): chuyen tiep quoc te, chuyen tiep dudng dai noi tinh va noi hat Rieng tai thanh pho Ho Chf M inh co them cap chuyen tiep noi hat

14 Mang the he sau va tien trinh chuyen d6i

Hien nay mang vien thong cua Viet Nam da co cac trung tam chuyen mach quoc te va chuyen mach quoc gia a Ha Noi Da Nang, Thanh pho Ho Chi' Minh M ang cua cac buu dien tinh cung dang phat trien m d rong Nhieu tinh, thanh pho xuat hien cac cau true mang vdi nhieu tong dai Host, cac thanh pho ldn nhu Ha Noi,

TP Ho Chi' Minh da va dang trien khai cac tong dai chuyen tiep noi hat

Mang nay do VTI, VTN va cac buu dien tinh quan ly VTI

quan ly cac tong dai chuyen mach chuyen tiep quoc te, VTN quan

ly cac tong dai chuyein mach chuyen tiep dudng dai tai 3 trung tam

Ha Noi, Da Nang va TP Ho Chi' Minh Phan con lai do cac buu dien tinh quan ly

Cac loai tong dai co tren mang vien thong Viet Nam: A1000E cua Alcatel, N EA X 61E cua NEC, A X E 10 cua Ericsson, EWSD cua Siemens

Cac cong nghe chuyen mach dugc su dung: chuyen mach kenh (PSTN) X.25 chuyen tiep khung, ATM (so lieu)

Nhin chung mang chuyen mach tai Viet Nam con nhieu cap va viec dieu khien bi phan tan trong m ang (dieu khien nam tai cactong dai)

M ang truy nhap: Vdi tung mang cung cap dich vu khae nhau

ma co mang truy nhap tuong urng

M ang truyen clan: Cac he thong thiet bi truyen dan tren mang

vien thong Viet Nam hien nay chii yeu sir dung hai loai cong nghe la: cap quang SDH va vi ba PDH

- Cap quang SDH: Thiet bi nay do nhieu hang khae nhau cung cap la: Northern Telecom Siemens Fujitsu, Alcatel Lucent NEC Nortel Cac thiet bi co dung lugng 155 Mbit/s 622 Mbit/s 2.5 Gbit/s

Chuong 1: Tong quan ve mang the he sau 15

- Vi ba PDH: Thiet bi nay cung co nguon goc tir nhidu hang cung cap khae nhau n h u Siemens, Alcatel, Fujitsu, SIS, SAT, NOKIA, AW A Dung lugng 140 Mbit/s, 34 Mbit/s va nx2 Mbit/s

C ong nghe vi ba SDH dugc su dung han che vdi so lugng ft

Mang truyen d i n co 2 cap: mang truyen dan lien tinh va mang truyen d in noi tinh

* M ang truyen d i n lien tinh

Bao g6m cac he thong truyen d in b in g cap quang, b in g vo tuyen.+ M ang tru y in d i n lien tinh b in g cap quang:

M ang truyen d i n duon g true quoc gia noi giura Ha Noi va

TP Ho Chf Minh dai 4000 km, sir dung STM-16/2F-BSHR, dugc chia thanh 4 vong Ring tai Ha Tinh, Da N ing , Qui Nhon va TP Ho Chf Minh

+ M ang truydn d i n lien tinh b in g vo tuyen:

Dung he thong vi ba SDH (STM-1, dung lugng 155 Mbit/s), PDH (dung lugng 4 Mbit/s, 6 Mbit/s, 140 Mbit/s) Chi co tuyen Bai Chay - Hon Gai dung SDH, cac tuyen khae dung PDH

* Mang truydn d i n noi tinh

Khoang 88% cac tuven truyen d in noi tinh sir dung he thong vi

ba Trong tuong lai khi nhu c iu tai tang thi cac tuyen nay se dugc thay the boi lie thong truyen d i n quang

M ang ban hieu

Hien nay tren m a n g v iin thong Viet Nam sir dung ca hai loai bao hieu R2 va SS7 M ang bao hieu so 7 (SS7) dugc dua vao khai thac tai Viet N am theo chien luge triin khai tir tren xuong dudi tlieo tieu chuan ciia ITU (khai thac thir nghiem tir nam 1995 tai VTN va VTI) Cho den nay m ang bao hieu so 7 da hinh thanh voi mot cap STP (Diem chuyen mach bao hieu) tai 3 trung tam (Ha Noi, Da N ing, TP Ho Chf Minh) ciia 3 khu vuc (Bac Trung Nam)

va da phuc vu kha hieu qua

16 Mang the he sau va tien trinh chuySn dot

Bao hieu cho PSTN co R2 va SS7, doi vdi mang truyen so lieu qua IP co H.323, doi voi ISDN co bao hieu kenh D Q.931

M ang dong bo da thuc hien xay dung giai doan 1 va giai doan

2 voi ba dong ho chii PRC tai H a Noi, D a N in g , TP Ho Chf Minh

va mot so dong ho thu cap SSU M ang dong bo Viet Nam hoat dong theo nguyen tic chit to co d u phong, bao gom 4 cap hai loai giao dien chuv6n giao tin hieu dong bo chii yeu la 2 M Hz va 2 Mbit/s Pha 3 ciia qua trinh phat trien mang d6ng bo dang dugc tridn khai n h im nang cao hon nua chat lugng m ang va chat lucmg dich vu

Chi/ang 1: Tdng quan ve mang the he sau 17

Cac cap cua mang dong bo dugc phan thanh 4 cap nhu sau:Cap 0: cap dong h6 chu

Cap 1: cap nut quoc te va nut quoc gia

Cap 2: cap nut noi hat

Cap 3: cap nut noi hat

M ang dugc phan thanh 3 vung doc lap, moi vung co 2 dong ho m&u, mot dong ho chinh (Cesium) va mot dong ho du phong (GSP) Cac dong ho nay dugc dat tai trung tarn cua 3 vung va dugc dieu chinh theo phuong thuc can dong bo

Cac tong dai quoc te va Toll trong vung dugc dieu khien bdi dong h6 chu theo phuong phap chu to

Cac tong dai chuyen tiep va Host tai cac tinh hoat dong bam theo cac tong dai Toll theo phuong phap chu to Cac tong dai huyen (RSS) cung hoat dong bam theo cac Host theo phuong phap chu to

M ang quan ly

D u an xay dung trung tam quan ly mang vien thong quoc gia dang trong qua trinh c h u in bi de tien tori trien

C ac nha cung cap dich vu

Tai nude ta co 2 dang nha cung cap di

cung cap dich vu truyen thong (chu yeu la thoai) va nha cung cap dich vu mdi (cac dich vu so lieu, Internet, .)

Cac nha khai thac dich vu truyen thong bao gom Tap doan Buu chinh Vi^n thong Viet Nam (VNPT), Tdng Cong ty Vien thong Quan doi (Viettel) C ong ty Co phan Buu chinh Vien thong Sai

G on (SPT), Cong ty Vien thong Dien lire (EVN Telecom)

Cac nha khai thac dich vu mdi bao gom FPT, SPT, Netnam

18 Mang the he sau va tien trinh chuyen 06

1.2 SI/H0I TU C U A HAI L O A I C O N G N G H E k £ t NO I 1.2.1 Ket noi dinh hirdng (CO: C onnetion O rien ted )

Ket noi dinh huong la cac cuoc goi ducrc thuc hien voi trinh tir: quay so, xac lap ket noi, gin va nhan thong tin, ket thuc Cac cuoc goi trong mang vien thong PSTN, ISDN, A T M la di£n hinh cua hoat dong ket noi dinh hudng

Mang dien thoai chuyen mach cong cong (PSTN) va mang so lien ket da dich vu (ISDN) co uu diSm la chat lugng mang td't, thiet

ke toi uu cho dich vu thoai va phi thoai voi do tr£ tha'p, do san sang cao, luon dam bao chat lugng dich vu thong tin Tuy nhien nhuqc diem cua 2 mang nay la mang bang hep, khong linh hoat, lang phi bang thong khi cac mach deu r6i, chi phi thiet lap va khai thac cao

De khae phuc nhugc diem tren thi cong nghe A T M ra ddi cho phep phat trien cac dich vu bang rong va nang cao chat lugng dich vu hon nua

1.2.2 Ket noi khong dinh hirdng (CL: C on n ection less)

Khae voi cac cuoc goi quay so true tiep theo phuong thuc ket noi dinh hudng la cac ket noi khong dinh hudng (CL) Do la cac hoat dong thong tin ^ iu a tren giao thuc IP nhu truy nhap Internet khong yeu c a u ’Viet?fcac lap trudc cac ket noi, vi vay chat lugng dich vu co the khong dugc dam bao, do san sang khong on dinh, khong toi uu cho dich vu thoai Tuy nhien do tinh don gian tien loi vdi chi phi thap, cac dich vu thong tin theo phuong thuc hoat dong phi ket noi phat trien rat m anh theo xu hudng nang cao chat lugng dich vu va tien tdi canh tranh vdi cac dich vu thong tin theo phuong thuc ket noi dinh hudng

1.2.3 Xu hirdng hoi tu C O va C L va sir ra ddi chuyen mach mdi

c ho N G N

Hai xu hudng phat trien nay dan tiem can va hoi tu vdi nhau tien tdi ra ddi cong nghe chuyen mach mdi ATM /IP Su phat trien

Chuong 1: Tong quan ve mang the he sau 19

manh me cua nhu c iu djch vu va cac cong nghe moi tac dong true tiep den sir phat tri^n cau true mang Do la nguon goc, dong luc cho su ra dcri va phat trien cua mang the he sau (NGN)

Khai niem mang the he sau ra ddi b it ngu6n tir sir phat trien cua cong nghe thong tin, cong nghe chuyen mach goi va cong nghe truyen d i n bang rong M ang the he sau co ha tin g thong tin duy

n h it dua tren cong nghe chuyen mach goi, tridn khai cac dich vu m6t cach da dang va nhanh chong, dap ung su hoi tu giua thoai va

so lieu, giua di dong va co dinh

C L

CO

Hinh 1.5: Cac xu hudng phat trien cong nghe mang

1.3 NHU C A U M O l V fi KHAI TH A C DICH VU V lfiN THONG 1.3.1 D o linh hoat

1.3.1.1 N hieu nha kh a i th ac tren m ot m an g vien th on g

Dd dang sir dung: K hach hang khong bi anh huong tir cac qua trinh tap trung, xir ly va truyen d i n thong tin phuc tap ciia he

20 Mang the he sau va tien trinh chuyen dti

thong No cho phep khach hang truy xuat va sir dung cac djch vu mang mot cach don gian hon bao gom cac giao dien ngudi dung cho phep tuong tac tu nhien giua khach hang va mang Khach hang dugc cung cap cac thong tin hudng dan, cac tuy chon, cac tuong tac quan ly xuyen suot cac dich vu Ngoai ra no con cung cap cac thuc don (menu) khae nhau cho nhung ngudi chua co kinh nghiem ngugc lai vdi nhung ngudi da co kinh nghiem va cung cap mot moi trudng thong nhat cho cac dang thong tin

1.3.1.2 Linh hoat ve diem kh ai thac dich vu

Muc tieu dat ra la khach hang co the lay thong tin ho muon 6 bat ky dang nao trong bat ky di£u kien nao, tai mgi noi va dung lugng tuy y

Lien lac thong tin rong khap, thdi gian thuc, da phucmg tien, dam bao do tin cay, than thien trong viec lien ket cac thue bao, truy nhap tdc do cao va truyen tai thong tin vdi bat ky phucmg tien nao, vao moi luc, tai moi noi,

Giai phap cua mang Internet don gian la sir dung cac thiet bi dau cuoi thue bao CPE (Customer Premise Equipm ent) tien tien nhu PC dien thoai thong minh (smart phone), settop-box, Dich

vu dugc thuc hien tai cac he thong d iu cuoi Cac xi nghiep cac cong ty phan mem va mot so trudng dai hgc, trung hoc se phat tri^n cac ung dung va tai chung tu mang Internet den cac thiet bi CPE Cac yeu cau doi vdi mang truyen tai cong cong la linh tin cay

va bang thong truyen dan cao

Cac dich vu tren nen mang co nhieu uu diem Vdi mot so nho cac dich vu don gian khong yeu cau lam viec giua khach han° vdi nhau cac dich vu tren nen CPE co the hieu qua Tuy nhien khi so lugng khach hang lam viec vdi nhau tang, cac dich vu tren nen mang to ra co nhieu loi the hem Vi du cac ung dung tren nen mang linh hoat hem va co kha nang m d rong hon so vdi cac dich vu

Chuong 1: TSng quan vS mang the he sau 21

tren n6n CPE Vdi cac ung dung tren n£n CPE, thiet bi CPE c in phai tinh vi, phuc tap hon, do do viec chi phi ton kem hon de dam bao cac yeu cau ve cac ung dung tien tien hon Giai phap tren nen

m ang cho phep chia se tai nguyen va de dang m d rong de dap un^cac yeu c iu do

Thur hai, djch vu tren nen CPE kho khan trong viec cung cap cac dich vu ddi vdi thue bao di dong Neu khach hang muon truy nhap vao cac dich vu cua ho tai nhung dia diem khae nhau, ho c in phai m ang thiet bi CPE theo hay tai phan mem tu vi tri mdi, lang phi thdi gian va tai nguyen mang Vdi cac dich vu tren nen mang, khach hang co the truy nhap vao cac dich vu cua ho bat ke tu vi tri nao Cuoi cung, cac van de khach hang quan tam nhu tinh cuoc, quan ly cau hinh, du phong va cac dang quan ly khae dugc xir ly de dang lion ddi vdi cac dich vu tren nen mang

T rong khi cac dich vu hien tai v in dugc cac nha cung cap giu lai, thi khach hang lai se hudng den cac dich vu da phuong tien bang rong va cac dich vu m ang nhieu thong tin Khach hang co the tuong tac vdi nhau thong qua mang nhd cac thiet bi CPE tinh vi va

co the chon tren pham vi rong chat lugng dich vu (QoS) va dai tan

T rong tuong lai, m ang thong minh se khong chi tao ra cac tuyen ket noi b in g cach dua tren co sd du lieu don gian ma con co the

m ang nhieu thong tin rong hon nhu: quan ly phien (session) da phuong tien, cac ket noi da cong nghe, dieu khien/quan ly thong minh, bao mat cao cac dich vu chi d in true tuyen, cac p h in tir giam sat

1.3.2 D o tuong tac

Cac m ang vien thong hien tai co dac diem chung la ton tai mot each rieng le, ung vdi m6i loai dich vu thong tin lai co it nhat mot loai m ang vien thong rieng biet de phuc vu dich vu do M6i mang dugc thiet ke cho cac dich vu rieng biet va khong the sir dung cho

22 Mang the he sau va tien trinh chuyen d6i

cac muc dich khae Vi du ta khong the truyen tieng noi qua mang chuyen mach goi X.25 vi tre qua mang nay qua Ion Ta can xem xet cac mang vien thong dang sir dung hien nay

- Xet ve goc do dich vu thi g6m cac m ang sau: mang dien thoai

co dinh, mang dien thoai di dong va mang truyen so lieu

- Xet ve goc do kv thuat bao gom cac mang chuyen mach mang truyen d in , mang truy nhap, mang bao hieu va m ang dong bo

Trong moi trudng co su rich hcrp ciia nhieu loai dich vu pham

vi thi trudng ciia cac dich vu co the sir dung dugc m o rong mot cach Ion manh gom cac loai hinh dich vu khae nhau va mang lien ket thong minh Moi trudng xir ly phan tan (DPE: Distributed Processing Environment) se giai phong ti'nh thong minh tir cac phan tir vat ly tren mang Do vay, tinh thong minh ciia mang co the dugc phan tan den cac vi tri thich hgp trong mang hoac neu co the, den ca CPE Vi du, kha nang thong minh ciia m ang co the nam 6 cac server (may chii) cho mot dich vu nao do, tren cac server nay thuc hien cac chuc nang cu the (vi du nhu cac diem dieu khien dich

vu SCP, cac nut (node) dich vu trong mot moi trudng AIN), hoac tren cac thiet bi d iu cuoi gan khach hang Cac kha nang thuc hien

se khong bi rang buoc trong cac thanh phan vat ly ciia mang

Cau true phan lop chia dieu khie’n dich vu/phien tir cac phuong thuc truyen tai co so Dieu nay cho phep cac nha cung cap lua chon (cho tirng trudng hop cu the) cac phuong thuc truyen tai thong tin khong phu thuoc vao phan mem dieu khie’n Dieu khien co the’ duoc phan tach thanh dieu khien dac ti'nh (feature), dieu khien dich vu/ phien, dieu khien ket noi Su phan tach giua truy nhap, dich vu

va dieu khien phien trong ldp dich vu cho phep m6i phien dugc xir

ly doc lap vdi cac phien khae Do do nhieu phien dich vu co the dugc bat d iu tir mot phien truy nhap Tuong tu, cac phien lien lac

co the dugc xir lv rieng le vdi phien dich vu noi chung ma chung la

bo phan (b in g each do cho phep dieu khien cuoc goi va ket noi

Chuong 1: T6ng quan ve mang the he sau 23

m6t cach rieng le) Dieu quan trong nh&'t la cac sir phan tach nay cho phep cac dich vu dugc phat trien doc lap vdi truydn d in va ket noi Do vay, cac nha phat trien dich vu co the khdng c in hieu het cac dich vu ho dang phat trien

Do do de cac nha khai thac dich vu vien thong tren cac mang khae nhau co the tuong tac vdi nhau c in phai: Tach ldp dich vu vien thong ra khoi tong dai

1.3.3 Yeu cau phat trien djch vu mdi

Su gia tang ca ve so lugng va chat lugng cua cac nhu cau dich

vu ngay cang phurc tap tu phfa khach hang da kfch thich sir phat trien nhanh chong cua cong nghe thong tin va vien thong Chung ta can xem xet xu hudng phat trien cac dich vu trong tuong lai

Cac dich vu tien tien ngay mot phat trien nhieu hon Cac dich

vu nay h iu het deu la sir ke't hgp cua thoai va du lieu B ing viec sir dung cac he thong nhan dang tieng noi, b it ky d i u cuoi nao ke ca chiec dien thoai truyen thong cung co the truy nhap cac dich vu tien tien C h in g han truy nhap thoai tdi Internet cho phep thue bao dien thoai co the tim kiem mot ten goi tren so dia chi true tuyen Sau khi da tim dugc ten, thue bao co the yeu c i u mot ket noi thoai dugc thiet lap chi don gian b in g cach noi mot tu khoa “call” Mot

vi du khae la kha nang bien tieng noi thanh van ban hay van ban thanh tieng noi cua dich vu U M S (Unfield M essage Service); cac kha nang nay cho phep ngudi sir dung co the nghe dgc cac email va cac ban fax qua may dien thoai hoac ngugc lai, hg co the’ giri fax hay email tir bat cu noi nao tren the' gidi b in g mot may dien thoai.Ti'nh di dong la m ot dong lire then chot cua cac dich vu tien tien Se khong co su han che nao ddi vdi cac d i u cuoi di dong Tinh "di dong ngudi d u n g " cho phep mot thue bao sir dung bat ky thiet bi d i u cuoi nao de truy nhap vao moi trudng dich vu tai nha ciia ho n h im sir dung dugc tat ca cac dich vu da dugc dang ky Mot

24 Mang the he sau va tien trinh chuyen d6<

tinh nang quan trong cua cac dich vu tien tien nay la chung dupe cung cap mot cach thong suot qua cac kieu thiet bi dau cuoi khae nhau ca di dong lan co dinh

Chang bao lau nura chung ta se thay rat nhieu dich vu da phuong tien mdi (chang han nhu cac cuoc goi co hien hinh giua ngudi nay va ngudi kia, cung sir dung chung tai lieu hay cac cuoc goi nhieu ben bang tieng noi va hinh anh) Cac dich vu dien thoai chu dao va viec lam chu cac ung dung cung dem lai nhieu dich vu tien tien khae ma ban than chung lai dong vai tro nh u mot dong lire

de tiep tuc md rong thi trudng cac dich vu dien thoai

Su phat trien ciia cac dich vu truyen thong hien nay se hudng tdi viec cac nha cung cap dich vu phai co sir mem deo linh hoat de phuc vu dupe ca thi trudng ldn va nho Khi co nhieu phuong tien truyen tin, nha cung cap dich vu, nha cung cap thiet bi va cac doanh nghiep thuong mai lien quan den viec cung cap dich vu, lien mang va cac he thong thuong mai se tro nen cang quan trong

Mang ludi hien nay khong the cung cap tat ca cac yeu cau cua khach hang, nen can phai co phuong phap de m d rong dich vu mdi Hien tai, thi viec cung cap mot dich vu mdi deu phai phu thudc vao tong dai

Ddi vdi mang hien nay, tai mot diem cung chi co the; cung cap mot loai dich vu ma thoi Do do mot veu cau dat ra la tai mot di£m cung cap dich vu co the cung cap nhieu loai dich vu Va giai phap Nut truy nhap da dich vu se cho phep mot nha khai thac cung cap bat ky mot su ket hop nao cua thoai' bang hep va thoai bang rong DSL va cac dich vu so lieu cho khach hang Mot giao dien V.5/GR.303 cung cap mot ket noi tdi cac mang dien thoai hien co: cac dich vu bang rong dupe h6 tro bdi cac giao dien ngudi dung tao

ra ket noi tdi cac mang SDH PDH va ATM

Nhieu thuc the va cac phan tir mang thong minh dupe phan bo tren toan mang No bao gom cac im g dung cho phep truv nhap va

Chi/ong 1: Tdng quan ve mang the he sau 25

dieu khien cac djch vu mang No cung co the thuc hien cac churc nang cu the thay the cho nha cung cap dich vu hoac mang Ta co the xem no nhu mot tac tu quan ly co the: thuc hien giam sat tai nguyen mang, tap hop cac so lieu,

De: dap ung su phat trien cua cac dich vu hien nay can phai co giao dien va cau true md Dac biet, moi trudng phat trien m d dua tren giao dien lap trinh ung dung (API) se cho phep cac nha cung cap dich vu, cac nha phat trien ung dung va cac khach hang tiem nang tao va gidi thieu cac urng dung mot cach nhanh chong No cung m d ra nhi^u co hoi de tao ra va phan phoi cac dich vu cho nhieu khach hang hem N hu vay, kha nang cung cap cac dich vu mdi va sang tao se chi bi gidi han bdi chmh su sang tao cua chung

ta ma thoi

Do do de dap ung dupe yeu cau phat trien mang thi chute nang dieu khien phai tach ra khoi t6ng dai

1.3.4 Yeu cau ve q uan ly m ang

Hien nay de dam bao truyen cac dich vu mot cach thong suot toan trinh (end to end) thi can phai thong nhat trong cach quan ly tir quan ly mang, quan ly dich vu den quan ly kinh doanh Do do mot mang hien dai phai co quan ly mang, quan ly dich vu va quan

ly kinh doanh Tat ca tao nen mot the thong nhat, nen ldp quan ly

la ldp dac biet xuyen suot 3 lop: ldp truy nhap, ldp thoi gian ldp chuyen tai va ldp dieu khien

Mo hinh cac ldp churc nang quan ly mang T M N do ITU dua rabao g6m:

- Quan ly phan tir mang

- Quan ly mang

- Quan ly dich vu

- Quan ly kinh doanli

26 Mang the he sau va tien trinh chuyen d&

So voi mo hinh quan ly mang do ITU dua ra thi cac chuc nang quan ly dupe chu trong doi vdi mang N G N la:

- Quan ly mang

- Quan ly dich vu

- Quan ly kinh doanh

Chi'fc nang quan ly m ang xem nhu da dupe thuc hien va hoan

thien d cac giai doan trudc khi trien khai NGN

Theo mo hinh chung cua cau true m ang mdi, ldp quan ly la mot ldp dac biet nham dam bao dap urng cac yeu c iu cua khach hang mot cach thong suot tu dau cuoi den dau cuoi N guyen tic quan ly nhu vay dupe TINA-C phan tich va trinh bay chi tiet trong cac tai lieu mo hinh cau true thong tin quan ly vi£n thong

Theo TINA, cau true thong tin quan ly vi6n thong dupe x&y dung trudc het dua tren mo hinh kinh doanh Nhin tu goc do nay, mot he thong vien thong bao gom cac p h in cung va phan m£m co kha nang cung cap cac dich vu tdi cac dai dien:

- Ngudi su dung

- Nha cung cap dich vu

- Cac nha cung cap mang (cung cap ket noi)

Do do quan ly mang phai xuyen suot cac ldp cua mang NGN.

1.3.5 N hung bat cap cua m ang the he hien nay

M ang PSTN hien tai dua tren nen tang cong nghe T D M va he thong bao hieu so 7 V6 co ban m ang nay mang hien nav v in co kha nang cung cap tot cac dich vu vien thong binh thudng nhu thoai hay Fax vdi chat lupng kha on dinh, tuy nhien nhu c iu cua ban than nha cung cap dich vu lan khach hang ngay cang tang lam boc lo nhung han che khong the khae phuc dupe cua mang hien tai

Chuong 1: Tdng quan ve mang the he sau 27

Ngay nay thi trudng vien thong trong nude va the gidi dang d trong cuoc canh tranh quyet liet do viec ldi long quan ly nha nude,

m d cua thi trudng cho tat ca cac thanh phan kinh te Cac nha cung cap dich vu dang phai dung trudc sure ep giam gia thanh dong thoi tang chat lugng dich vu Sir xuat hien dich vu Internet va sir phat triSn bung no cua no dan den nhung su thay doi dot bien ve co sd

m ang buoc cac nha cung ca'p dich vu phai “ thay ddi tu duy” Dudi day la m ot sd han che cua m ang hien tai:

a C u n g nhac tro n g viec p h a n bo ban g thon g

Miing PSTN dua tren cong nghe TD M trong do dudng truyen dugc phan chia thanh cac khung co dinh la 125 fis M6i khung dirge chia thanh cac khe thoi gian (Timeslot) K enh co sd dugc tinh tuong duong vdi m ot khe thdi gian tuc la 64 kbit/s Dieu nay dan den mot sd bat lgi, vi du nhu ddi vdi nhieu loai dich vu doi hoi bang thong thap hon thi cung khong dugc, hay nh u ddi vdi cac dich

vu co nhu cau bang thong thay doi thi T D M cung khong the dap ung dugc Cuoc goi T D M dugc phan bo lugng bang thong co djnh (N x 64 kbit/s) va cac khe thdi gian nay dugc chiem co dinh trong suot thdi gian di6n ra ket noi dan den lang phi bang thong Chuydn

m ach goi quan ly bang thong mem deo theo nhu cau djch vu cho nen rat tiet kiem bang thong

b K h o khan cho viec to h op m ang

M ang ngay nay cung ca'p cac loai dich vu vi6n thong khae nhau nhu thoai, d u lieu hay video tren cac m ang tach biet nhau M6i m ang lai yeu cau phuong phap thiet ke, san xuat, van hanh, bao dudng khae nhau Dac biet m6i mang chi truyen dugc cac dich

vu doc lap rieng Tai nguyen san co trong m ot mang khong the chia se cho cac mang khae cung sir dung N6 lire to hgp tat ca cac mang nay thanh mot m ang duy nhat dugc thuc hien tir nhung nam

1980 vdi mo hinh m ang ISDN bang hep van dua tren n6n cong

28 Mang the he sau va tien trinh chuyen d6i

nghe TDM, xong cung gap phai mot so kho khan nhu toe dp thap, thiet hi m ang cong kenh, phuc tap, y tuong mang ISDN bang rong dua tren nen cong nghe ATM dupe dua ra co ve nhu qua dat do doi voi ngudi tieu dung Va lai ATM cung khong linh hoat khi hoat dong d toe do thap

c K ho khan trong viec cung cap dich vu m oi, thieu tinh m em deo

Trong mang PSTN, toan bo phan “ thong m inh” cua m ang deu tap trung d cac tong dai Mot dich vu mdi dupe trien khai bat dau

tu tong dai den den su thay doi phan m em doi khi ca phan cung cua tPng dai, dieu nay rat phuc tap va ton kem Nhu cau khach hang khong ngirng tang, nhieu loai dich vu mdi khong the thuc hien tren nen mang TDM Su ra ddi cua cac cong nghe mdi anh hudng manh

me tdi toe do truyen tin hieu Ngoai ra, se xuat hien nhieu dich vu truyen thong trong tuong lai ma hien nay chua du doan dupe, m6i loai dich vu se co toe do truyen khae nhau Ta de dang nhan tha'y mang hien tai se rat kho thich nghi vdi nhung doi hoi nay

d D au tu cho m ang P S T N lorn, kh o n g linh hoat tro n g viec

m a rong he thong Von dau tu tap tru n g tai cac tru n g tam chuyen m ach

Thuc te dau tu cho cac thiet bi m ang PSTN rat ldn (so vdi mang IP) Cac tPng dai thuong rat d it, can phai dau tu ca cuc Chi phi nhan cong cho viec van hanh bao dudng mang rat cao Kem hieu qua trong viec bao dudng, van hanh Cac chuc nang phan cung

va phan mem cung tap trung tai cac tPng dai nen phuc tap khi thay ddi Mang co nhieu cap gav phuc tap trong viec phoi hop he thong bao hieu dong bo va viec trien khai dich vu mdi Phuc tap trong viec thiet lap Trung tam quan lv mang he thong ti'nh cudc chain soc khach hang v.v Mat khae m ang vien thong hien na\ duoc thiet ke nham muc dich khai thac dich vu thoai la chu veu Do do

Chuong 1: Tdng quan ve mang the he sau 29

dung d goc do nay, mang da phat trien tdi mot muc g in nhu gidi han ve su cong kenh va mang ton tai mot sd khuyet diem c£n

k h ic phuc

e G id i han tro n g p h a t trien m ang

Cac tong dai chuyen mach noi hat deu su dung ky thuat chuyen m ach kenh, cac kenh thoai deu co toe do 64 kbit/s Qua trinh bao hieu va dieu khien cuoc goi lien he chat che vdi co cau chuyen mach

Ngay nay, nhung loi ich ve mat kinh te ciia thoai goi dang thuc day sir phat trien ciia ca m ang truy nhap va mang dudng true tir chuyen m ach kenh sang goi Va bdi vi thoai goi dang dan dupe chap nhan rong rai trong ca mang truy nhap va mang dudng true, cac tong dai chuyen m ach kenh noi hat truyen thong dong vai tro cau noi ciia ca hai m ang goi nay Viec chuyen doi goi sang kenh phai dupe thuc hien tai ca hai dau vao ra ciia chuyen mach kenh, lam phat sinh nhung chi phi phu khong mong muon va tang them tre truyen d i n cho thong tin dac biet anh hudng tdi nhung thong tin nhay cam vdi tie dudng truyen nhu tin hieu thoai

Neu ton tai mot giai phap ma trong do cac tong dai noi hat co thd cung cap dich vu thoai va cac dich vu tuy chon khae ngay tren thiet bi chuyen mach goi, thi se khong phai thuc hien cac chuyen doi khong can thiet nira Dieu nay mang lai loi ich kep la lam giam chi phi va tang chat lupng dich vu (giam tre dudng truyen), va

do cung la mot budc quan trong tien gan tdi cai dich cuoi cung,

30 Mang the he sau va tien trinh chuyen <36i

con tang m anh vao nhung nam sau trong khi luu lugng thoai cd dinh dudng nhu co xu hudng bao hoa tham chf giam d mot sd nude phat trien Internet da tham nhap vao moi goc canh cua ddi song xa hoi vdi nhieu y tudng rat mdi nhu: dao tao tu xa, y te tu xa, chinh phu dien tir hay tin hoc hoa xa hoi v.v Su bung n6 luu lugng thong tin da chi ra sir kem hieu qua cua chuyen mach kenh TDM Chuyen mach kenh truyen thong chi dung de truyen cac liru lugng thoai co the d u doan trudc, va no khong h6 trg luu lugng d u lidu tang dot bien mot each hieu qua Khi lugng du lieu tang vugt luu lugng thoai, dac biet ddi vdi dich vu truy nhap Internet quay sd true tiep, thuong xay ra nghen mach do nguon tai nguyen han hep

Hien tai dich vu Internet phat trien nhanh den chong mat tai Nhat Ban Trong xa hoi “thong tin tri thurc” , dudng nhu moi hoat dong deu co lien quan tdi Internet nhu hgc tap, nghien curu khoa hoc va vui choi giai tri, dich vu da phuong tien tang m anh doi hoi lugng bang thong ldn Nhu cau ve dich vu IP VPN cung rat ldn Nhieu dich vu gia tri gia tang dua tren mang Internet xuat hien thuc day nhu cau truy nhap mang tang len

k K ho khan cho cac nha kh ai thac

Kien true tong dai doc quyen lam cho cac nha khai thac g in nhu phu thuoc hoan toan vao cac nha cung cap tong dai Di£u nay khong nhung lam giam sue canh tranh cho cac nha khai thac, dac biet la nhung nha khai thac nho, ma con ton nhidu thdi gian va tien bac khi m uon nang cap va ung dung cac phan mem mdi

Cac tdng dai chuyen mach kenh da khai thac het nang luc va trd nen lac hau ddi vdi nhu cau cua khach hang Cac chuve'n mach Class5 dang ton tai lam han che kha nang sang tao va trien khai cac dich vu mdi tir do dan den viec lam giam lgi nhuan cua cac nha khai thac

Chuong 1: Tdng quan ve mang the he sau 31

D ung trudc tinh hinh phat trien cua mang vien thong hien nay, cac nha khai thac nhan th iy r in g “ su hoi tu giura mang PSTN va

m ang PSDN” la c h ic c h in xay ra Ho c i n co mot co sd ha tin g duy

n h it cung c i p cho moi djch vu (tuong tu - sd, bang hep - bang rong, c o ban - da phuong tien, ) de viec quan ly tap trung, giam chi phf bao dudng va van hanh, dong thdi h6 tro cac djch vu cua

m ang hien nay

+ M ang p h in phoi (phan phoi tmh thong minh cho moi p h in tu trong m ang)

+ M ang nhieu ldp (m ang dupe phan phoi ra nhieu ldp mang co chuc nang doc lap nhung h6 tro nhau thay vt mot khoi thong nhat nhu trong m ang TDM)

Cho tdi hien nay, mac du cac to chuc vien thong quoc te' va cung cac nha cung cap thiet bi vien thong tren the' gidi deu rat quan tam va nghien cun ve chien lupc phat trien N G N nhung v in chua

co mot djnh nghla cu the’ va chinh xac nao cho mang NGN Do do djnh nghla m ang N G N neu ra d day khong the bao ham het moi chi tiet ve m ang the he sau, nhung no co the tuong ddi la khai m em chung n h it khi de cap den NGN

B it nguon tu su phat trien cua cong nghe thong tin, cong nghe chuyen mach goi va cong nghe truyen d i n bang rong, mang thong

32 Mang the he sau va tien tnnh chuyen (J6i

tin the he sau (NGN) ra ddi la mang co c o so ha tang thong tin duy nhat dua tren cong nghe chuyen mach goi trien khai cac dich vu mot cach da dang va nhanh chong, dap img su hoi tu giua thoai va

so lieu, giua co dinh va di dong

Nhu vay, co the xem mang thong tin the he sau la su tich hop mang thoai PSTN, chu yeu dua tren ky thuat TD M voi mang chuyen mach goi dua tren ky thuat IP/ATM No co the truyen tai tat ca cac dich vu von co cua PSTN dong thdi cung co the nhap mot lugng du lieu rat ldn vao mang IP, nhd do co the giam nhe ganh nang cua PSTN

Tuy nhien, NGN khong chi don thuan la su hoi tu giua thoai va

du lieu ma con la su hoi tu giua truyen dan quang va cong nghe goi, giua mang co dinh va di dong Van de chu dao d day la lam sao co the tan dung het lgi the dem den tu qua trinh hoi tu nay Mot van dd quan trong khae la su bung nd nhu cau cua ngudi sir dung cho mot khoi lugng ldn dich vu va ung dung phuc tap bao gom ca

da phuong tien phan ldn trong do la khong dirge tru lieu khi xay dung cac he thong mang hien nay

1.4.2 D ae diem eiia NG N

- Nen tang la he thong m ang md

- M ang NGN la do mang dich vu thuc day nhung dich vu phai thuc hien doc lap vdi mang ludi

- M ang NGN la mang chuyen m ach goi, dua tren mot giao thuc thong nhat

- La mang co dung lugng ngay cang tang, co ti'nh thich ung cung ngay cang tang, co du dung lugng de dap ung nhu cau

Trudc het do ap dung co cau m d ma:

Chuong 1: Tdng quan ve mang the he sau 33

- Cac khdi churc nang cua tong dai truyen thong chia thanh cac phan tir m ang doc lap, cac phan tir dupe phan theo chuc nang tuong ung, va phat trien mot cach doc lap

- Giao dien va giao thuc giua cac bp phan phai dua tren cac tieu c h u in tuong iimg

Viec phan tach lam cho mang vien thong von co d in dan di theo hudfng mdi, nha kinh doanh co the can cu vao nhu cau dich vu

de tu tP hop cac p h in tir khi to chuc mang ludi Viec tieu chuan hoa giao thuc giua cac p h in tir co the thuc hien noi thong giua cac mang co cau hinh khae nhau

Tiep den, mang NGN la mang dich vu thuc day, vdi dac diem ciia:+ Chia tach dich vu vdi dieu khien cuoc goi

+ Chia tach cuoc goi vdi truyen tai

Muc tieu chinh ciia chia tach la lam cho dich vu thuc s u doc

lap vdi m ang, thirc hien mot each linh hoat va co hieu qua viec

cung cap dich vu Thue bao co the tu bo tri va xac dinh dac trung dich vu ciia minh, khong quan tam den m ang truyen tai dich vu va loai hinh dau cuoi Dieu do lam cho viec cung cap dich vu va ung dung co tfnh linh hoat cao

T h u ba, N G N la m ang chuyen mach goi, giao thuc thong nhat

M ang thong tin hien nay, du la mang vien thong, mang may tinh hay mang truyen hinh cap, deu khong the lay mot trong cac mang

do lam nen tang de xay dung co sd ha t in g thong tin Nhung may nam g i n day, ciing vdi sir phat trien cua cong nghe IP, ngudi ta mdi

n h in thay ro rang la mang vien thdng, mang may ti'nh va mang truyen hinh cap cuoi ciing roi cung ti'ch hop trong mot mang IP thong nhat, do la xu the ldn ma ngudi ta thudng goi la “dung hop

ba m ang ” Giao thuc IP lam cho cac dich vu lay IP lam co sd deu

34 Mang the he sau va tien trinh chuySn

co the thue hien noi thong cac m ang khae nhau; con ngudi Ian d iu tien co dupe giao thuc thong nhat ma ba mang ldn deu co the ch ip nhan dupe; dat co sd vung chac ve mat ky thuat cho ha t in g co so thong tin quoc gia (Nil)

Giao thuc IP thuc te da trd thanh giao thurc umg dung van nang

va b it d i u dupe sir dung lam co sd cho cac mang da dich vu, mac

du hien tai v in con d the bat loi so vdi cac chuyen mach kenh \ i

mat kha nang h6 tro luu lupng thoai va cung cap chat lupng dich vu dam bao cho sd lieu Toe do doi mdi nhanh chong trong the gidi Internet, ma no dupe tao dieu kien bdi su phat trien ciia cac tieu

c h u in m d se sdm khae phuc nhung thieu sot nay

Hinh 1.6: Topo mang the lie sau

Chuong 1: Tdng quan ve mang the he sau 35

1.4.3 N hung van de can quan tam khi phat trien NGN

Trudc het cac nha cung ca'p djch vu chinh thong phai xem xet

c o so TD M m a ho da lap dat va do vay phai ddi dau vdi quye't djnh

kho khan \6 viec nang ca'p he thong nay, nen dau tu von cho thiet

bj chuyen mach kenh va xay dung mot mang NGN xep ch6ng, hay tham chf nen thay the cac tong dai truyen thong bang nhung chuyen mach cong nghe mdi sau nay Ho cung phai xem xet anh hudng cua su gia tang luu lupng Internet quay sd true tiep vdi thdi gian giu m ay ngdn hem nhieu De duy tri canh tranh cac nha khai thac nay c&n tim ra phuong phap cung ca'p cac djch vu mdi cho cac khach hang cua ho trong thdi ky qua dd trudc khi cac mang cua ho tien triSn sang NGN mot each day du

Van de ldn nhat can can nhac khi sap tdi can h6 tro djch vu thoai qua IP va hang loat cac djch vu gia trj gia tang khae la co che

“ best effort” (co gang tdi da) phan phoi cac goi tin khong con du dap ung nua M ot thach thuc can ban d day la m d rong mang IP theo nhieu hudng, kha nang cung cap da djch vu trong khi van giu dupe uu the' cua m ang IP De’ dam bao QoS can thiet, cac nha khai thac se phai co kha nang cam ke't cung cap cac thoa thuan ve muc djch vu (SLA), cac yeu cau ve bang tan va cac tham sd chat lupng.Mot khfa canh khae bao dam chat lupng la quy mo m ang phai

du ldn de cung cap cho khach hang nham chong lai hien tupng nghen co chai trong luu lupng cua m ang loi Mot trong nhung dac trung cua NGN chinh la kha nang tang sd lupng cua cac giao dien

md, nhung dieu do cung ham chura cac nguy co de doa an ninh cua mang Do do, dam bao an toan thong tin trd thanh van de song con cua cac nha khai thac nham bao ve m ang chong lai su tan cong tu phia cac tin tac Cac cong cu an ninh va mat ma hoa phai luon luon san sang

36 Mang the he sau va tien trinh chuySn doi

Trong vong hai thap ky vira qua, cong nghe quang da chunig minh dupe la mot phuong tien truyen tai thong tin hieu qua tren khoang cach Ion, va hien nay no la cong nghe chu dao trong truyen

d in tren mang loi Voi cac cai tien hien nay, nhu cong nghe ghep kenh phan chia theo mat dp budc song D W D M , nang cao dang ke

hieu qua kinh te v& truyen tai tren m ang cap quang Ngay nay, IP

theo du kien se tro thanh giao dien hoan thien thuc su cho cac mang loi NGN Van d6 quan trong 6 day la m ang cap quang phai toi uu cho di6u khien luu lupng IP Mot giai phap co ti'nh thuyet phuc hien nay la hoi tu cac ldp d u lieu va cac ldp quang trong mang loi Viec hoi tu nay mang lai mot sd loi the nhu cung cap cac dich vu toe do cao, bao ve dong thong tin lien tuc cho m ang quang vdi chuyen mach nhan da giao thuc chung MPLS

Mot van de khong kem p h in quan trong la van dd \6 cac giai

phap quan ly thich hop cho mang NGN Trong khi mong muon xiy dung mot mang quan ly phai lam viec trong mot moi trudng da nha dau tu, da nha khai thac, da dich vu con m ang tinh logic, tuy vay

no vin boc lo nay la diem rat can luu y Mac du con phai mat nhieu thdi gian va cong sue trudc khi he thong quan ly mang dupe trien khai, nhung muc tieu nay v in co gia tri thuyet phuc va se m ang lai nhieu loi ich nhu giam chi phi khai thac, dich vu da dang

Tat ca nhung yeu to tren nay dudng nhu lam cho N G N trd len phuc tap Tuy nhien nen nhin m ang N G N trong mang thong tin toan c iu ngay nay trong do cac m ang chuyen mach kenh truyen thong va chuyen mach goi song song ton tai, cac mang di dong va

co dinh khong don gian trong viec cung khai thac, va tham chi cac thanh p h in mang khae nhau tren mang cung yeu cau phan quan ly rieng biet Tren quan diem do NGN hudng \6 mot cai gi do het sure phuc tap nhung se cho phep tiet kiem chi pin' khai thac mot each thich dang

da anh hudng manh me ddi vdi cau true mang, anh hudng true tiep den sir ton tai va phat trien ciia cac hang san xuat cung cap thiet bi, cac nha khai thac vidn thong.

Vdi sir tham gia ciia cac hang va cac nha khai thac nay, mang the he sau la van de thu hut su quan tam ciia nhieu to chuc vi6n thong n h im hudng tdi mot mo hinh cau true mang mdi tren n6n tiing cong nghe hien dai, dau tu hieu qua, dap irng cac yeu cau phat trien phong phu va da dang cac dich vu Trong do co the ke’ den hoat dong ciia cac t6 chuc vien thong sau day:

- ITU-T vdi cac nhom S G I6, SGI I, S G I 3, SG2, SG8

- IETF vdi cac nhom PINT W G (PSTN and Internet Intem et_ working), M M U SIC W G (Multiparty M ultimedia Session Control), IPTEL (IP Telephony), SIGTRAN W G (Signalling Transport)

- MSF (Multiservice Switching Forum - Di6n dan chuyein mach

38 Mang the he sau va tien tnnh chuySn d&

- ISC (International Softwitch Consortium - Td chac quoc te

nghien cuu v i chuyen m ach mem).

- TINA (Telecommunication Infonnation Networking Architecture Consortium - Hiep hoi nghien euru c i u true m ang thong tin vidn thong)

- A M F (Asian M ultimedia Forum: Di£n dan da phuong tien chau A) Dien dan nay dugc thiet lap tu nam 1996 va den nam

1997 da co 55 thanh vien voi cac nghien cuu dinh hudng kien true phat trien bao gom: co sd ha tang, dich vu mang, ung dung, thi trudng Cac d6 an thu nghiem da dugc thuc hien d khu vuc chau A la: thu nghiem ATM vdi cac tuyen 45 Mbit/s Nhat Ban - Hong Kong, 2 Mbit/s Nhat Ban - Thai Lan, 2 M bit/s Nhat Ban - ln-do- ne-xi-a va cac thu nghiem khae nhu cac dich vu m ang quan ly mang, ket noi, cac ung dung VoA TM (Voice over ATM )

Tuy nhien cho den thdi diem nay, chua co mot m d hinh nao dugc cac to chuc chinh thuc xem nhu mo hinh c h u in cho mang NGN, cac ket qua nghien euru hau het v in dang d dang dugc tiep tuc phat trien

Sau day la mot so mo hinh m ang can quan tam:

2.1.1 Mo hinh ITU

Cau true mang the he sau NGN n im trong mo hinh ldn cua cau true co sd ha tang thong tin toan cau GII (Global Information Infrastructure) do ITU dua ra Mo hinh nay bao gom 3 ldp churc nang sau:

- Cac chuc nang ung dung

- Cac churc nang trung gian, bao gom:

+ Cac chuc nang didu khien dich vu

+ Cac churc nang quan ly

Chuong 2: Cau true mang the he sau 39

- Cac churc nang c a sd bao gom:

+ Cac churc nang m ang (bao gom chuc nang chuyen tai va chifc nang dieu khien)

+ Cac chuc nang x u ly va luu tru

+ Cac chuc nang giao dien ngudi - may

P h in mang truy nhap bao gom cac ket noi:

- Vo tuyen: Dien thoai khong day/thong tin di dong

- Huu tuyeii: Dien thoai tuong tu truyen thong

M o hinh thuc hien cua GII dupe phan doan nhu sau:

- Phan doan mang quoc te

- Phan doan m ang loi (Core)

- Phan doan mang truy nhap

- Phan doan mang khach hang

Truyen thong

Hinh 2.1: Cdc chuc nang GII va mdi quan lie cua chung