Giáo trình dành cho kỹ sư cntt cơ bản bản 4

T r-1Li N(.-) i / \fv! SA I I fA C
HAN

iY

i- H 'i

( ( !iv(

CONG NGHE'- TH O N G TIN VA HO T R O ‘ DAG TA O
(.A.O HOa

i Ac' • BO

KHOA

HOC VA CONG

NGHF

V! i

GIAO TRINH DANH CHO KY SIT CNTT COT BAN
Tai lieu IuTj hanh noi bo
Ban a
o'

:

O

r

.


1

luc
ft/IUC
a
t*

M yc ly c ............................................................................................................................................................................................................1
Phan 1 Cong nghf M $ng...........................................................................................................................................................................9
1

Cac giao thuc va dieu khien truyen......................................................................................................................................

10

Myc tieu cua chuong........................................................................................................................................................................... 10
Giai thi$u.......................................................................................................... .......................................................................................11
1.1

Kien

1.1.1

true mang............................................................................................................................................11

Boi canh ra dai cua Kien true m an g ................................................................................................................... 11

1.1.2 Nguyen tSc chung va cac chuan cua Kien true m ang.................................................................................................. 12
1.1.3

Cac kieu kien true m ^ng............................................................................................................................ 14

1.1.4

Cac chuan thyc te (De Facto) ............................................................................................ ........ ...................14

1.1.5

To po mang va cac plurang phap ket n o i..............................................................................................................14

1.2

OS! - chuan hoa cho giao thirc truyen thong. ................................................................................................................ 17

1.2.1

Tong quan ve O SI...................................................................................................................................17

1.2.2

Mo hinh tham chieu OSI co ban.......................................................................................................................18

1.2.3

Cac thu tyc truyen thong trong OSI...................................................................................................................21

1.3

7 CP/IP - chuan thyc te cho giao thuc truyen thong....................................................................................................23

1.3.1
1.3.2
J .4

Tong quan ve TC P/IP.......................................................................................... ..................................... 23
Cac thu tyc truyen thong trong TCP/IP......................................... ..............................................................26

Dja chi duyc su dyng cho TC P/IP.......................................................................................................................................27

1.4.1

Dia chi I P ........................................................................................................................................... 27

1.4.2

Dja chi MAC ........................................................................................................................................ 33

15

Gi«u>dj<£n thiet b| cuoi ...........................................
I S. I

IJm ig -V

I

Don}' X

"■?

........................................................................... 32
..........................

I.}

Vt


2
1.5.3

D ong-I.................................................................................................................. ...................................................3 3

154

RS-232C................................................................................................................ ................................................

Dieu khien tru yen .................................................................................................................................................................. 34

i .6
1.6.1

Tong quan va luong dieu khien truyen................................................... .....................................................34

1.6.2

Cac thu tye dieu khien truyen..................................................................... ................................................,...36
Bai t§p ..........................................................................................................................................................................................42

1.7
2

34

Ma hoa va truyen tai.................................................................................................................. .....................................................45
Myc tieu cua ch u o n g ...................................................................................................................... .....................................................45
Gidi thi^u............................................................... ................ ........................................................... .....................................................46
2.1

Ma h6a va dieu ch e ........................ .................................................................................................... ....................... ........... 46

2.1.1

Ducmg truyen thon g...................................................................................... .....................................................46

2.1.2

Ky thuat dieu c h e ............................................................................................

2.1.3

Ky thu|t ma h o a .............................................................................................. .....................................................48
Cong ngh$ tru y en ............................................................................................ .................. .....................................................49

2.2

2.2.1

Kiem tra loi........................................................................................................ ..................................................... 49

2.2,2

Kiem tra dong b g ............................................................................................. ..................................................... 52

2.2.3

Phuong phap don kenh................................................................................ ..................................................... 54

2.2.4

Phuong phap nen va giai nen.....................................................................
Phuong phap truyen va d u 6ng truyen thong......................................................... ..................................................... 59

2.3
2.3. j

Cac lop cua kenh truyen............................................................................... ..................................................... 60

2.3.2

Cac kieu duong truyen................................................................................. ................................................ ....61

2.3.3

Cac phuong phap chuyen mach........................................ ........................ ..................................................... 62
Bai t$p ................................................................................................................................... ..................................................... 70

2.4
3

Cac mang (LAN va W AN )...................................................................................................... ..................................................... 73
Muc tieu cua chut wig.................................................................................................................... ..................................................... 73
'7 1

Gidi th*£u

...........................................................................................................................

3 1

........................................................................................................................... ............................................. .........74

LAN

i.1

i :i th

<:iM i A N .......................................................................................

7..J

7S

1 13

k J.V,, I,/,. J,%
.V|

LAN

.................................................................................

rr )


3

3 .1.4

Cac ca’u phan LA N.............................. ....... .............................................................................................................. 78

3.1.5

Phuang phap kiem soat truy nhap mang LA N .................................- ........................ ............................. 83

3.] 6

TI>iei bi ke\ noi Jien-LAN. ........... ........................................................................... ........... ..................................88

3.1.'/

Cong ngh£ tang toe dp mang LAN....................................................................................................................... 91

3 2

Internet................................................... .....................................................................................:............................................. 92

3.2.1

Boi dinh ljch su cua vi§c phat trien Internet.................................................................................................... 93

3.2.2

Cau true cua Internet............................................................. ............................................... ..................................94

3.2.3

Cong ngh£ Internet.................................................... ............................................................................................... 96

3.2.4

Loai hirih may chu (servers)................ ................................................................................................................. 97

3.2.5

C’£c djch vy Internet................................................................................................................................................100

3.2.6

May tim kiem ............................................ ........................................................................ ..................................... 103

3.2.7

Cac kien thuc lien quan toi Inem et....................................................................................................................104

3 .3

An ninh m ang........................................................................................................................................................................... 105

3.3.1

Bao ve tinh kin va ngan ch|n gid in ao .............................................................................................................. 106

3.3.2

Xam nhap bat h
3.3.3

Cac bif n phap dam b io tinh sin sang............................................................................................................. 115

3.3.4

Bao vf tinh rieng t u ..........................................................................................................................................

3.4
4

113

117

Bai t|p..................... ....................................................... ’..........................................................................................................120

Thiet bj truyen thong va phan mem mang.............................................................................................................................124

M uc tieu cua chuong..........................................................................................................................................................................124
4.1

4.1.1

Phuang tien truyen (Cap truyen thong).......................................................................................................... 125

4.1.2

Thiet bj truyen thong ngoai vi.............................................................................................................................128

4.2

Phan mem mang....................................................................................................................................................................... 130

4.2.1

Quan ly m ang...................................... .................................................................................................................... 130

4.2.2

Me dieu hanh mang (:\!<)S) ................................................................................

4.3
5

Thiet bj truyen thong............................................................................................................................................................... 125

..............................132

Bai lap..................................................................................................... ................................................................................... 135

C up niuil vt*Cong ngi it;mang ..

.......................................................................

........................... 137


5.1

Tien ho Cong n g h e................. ........................................................ ..................... ...... ......................................... ............. ..138

5.1.1

Tien hoa trong vien thong..................................................................................................-........................ —*138

5.1.2

LAN khong d a y ........................................................................................................................ -........................ I4i

5.2

6

XML (Ngon ngu* danh dau mo rp n g)......................................................................................... ....................................146

5.2.1

XML(Ng6n ngu* danh dau md rQng)......... .............................................................................................. .......147

5.2.2

Unicode va van ban khong phai Latin (Non roman)............................................................................ ...149

5.2.3

Khong gian ten (Namespace)........................................................................................................... .......... .......151

5.2.4

DTD (Djnh nghla kieu tai lieu)......................................................................................................................-152

5.2.5

Djnh nghia 1ii
5.2.6

XSL (Ngon ngir kieu cach trang mo rpng)..........................................................................................

5.2.7

Mo hinh doi tugng tai lieu X M L ........... ...................................................................................................... . 158

5.2.8

Su* dyng XML trong tai lieu HTML..................................................................... ......... ................ ..................161

5.2.9

Giao dien XML SQL Server O LE-D B.............................................................................. .................................. 162

5.2.10

May dau trudc da phuong tien (Flash)............................................................................................................. 165

Tra ldi bai t|p..................................................................................................................................................................................167
6.1

Tr& lai bai tap cho Quyen 4 Phan 1 Chuang 1 (Cac giao thuc va kiem soat truyen)....... .............................. 167

6.1.1

Danh sdch dap a n .............................................................................................................. ........................ ...........167

6.1.2

Dap an va H uang d an ........................... ............. !............................... ............................................................. 167

6.2

Tra loi cho Quyen 4 Phan 1 Chuong 2 (Ma hoa va truyen tai)............................................. .................................... 172

6.2.1

Danh sach dap a n ................................................................................................................................................... 172

6.2.2

Dap £n va Hudng d an .................................................................................................................................. .......172

6.3

Tra ldi cau hoi cho Quyen 4 Phan 1 Chuong 3 (Cac mang (LAN va W A N ))................................................. ...1 7 8

6.3.1

Danh sach dap a n ................................................................................................................................................... 178

6.3.2

Dap an va Huong J a n ..........................................................................................................................................178

Tra loi bai tap cl to Quyen 4 Phan 1 Chuong 4 (Thiet bi truyen thong va phan mem m ang)........................... 183

6.4
6

4 I

b 4.2

i )anh sach dap a n ................................................................................................................................................... 183
Dap an va I iuong d an .....................................................................................................................................

Phan ? Cdng nghv co >*>’

157

!

on v

o u . ' H ) v 1 c o s»o
.................
.. .

.

184
.186


i.I

Muc dich cua CSDL.............................................................................................................................. .................................188

!2

Mb hinh CSD L..................................................................................................................................... .................................. i 89

1.2 j.

Mo hinh hoa du li^ii.............................................................................................. ........................................... 190

1.22

Mo hinh dir h£u khai niern....... ......................................................................................................................... 190

1.2.3

Mo hinh du lieu logic................................................................. .................. ........•.............................................191

1.2.4

Lu
13

Phan tich du lieu.................... ................................................................................................................................................193

1.3.1

ERD............................................................................................................................................................................. 193

1.32

Chuan hoa.................................................................................................................................................................194

14

Thao tac du it£u ......................................................................................................................................................................197

1.4.1

Phep toan t£p hop.................................................................................................................................................. 197

1.42

Phep quan h e........................................ .................................................................................................................. 199

15

Bai tap........................................................ ^......................................................................... ............................... ..................... 201

2

Ngon ngu co s6 du li£u.................................................................................................................................. .............................. 205
Muc tieu cua chucrng............................................................................................................................................................................ 205
21

Ngon ngu co so du li$u la g i?.............................................................................................................................................. 206

2.1.1

Ngon ngu djnh nghla du lie u ..........................................................................................................................206

2.12

Ngon ngu* thao tac du li§ u ................................................................................................................................206

2.13

Ngon ngu ngudi dimg cuoi..................................................................................................................................206

22

SQL............................................................................................................................................... ............................................... 207

2.21

SQL; Ngon ngu ca so du li§u...............................................................................................................................207

2.22

Cau true cua SQ L......................................................................................................................................................207

1.3

Djnh nghia ca sa dir du li
2.31

Djnh nghla ca so du* ti£u..................................................................................................................................... 208

2 .3 1

Dinh nghia Suae d o ............................................................................................................................................... 209

2.33

Djnh nghui baiig.................................................................................................................................................. 210

2.3 4

D§c irung va djnh nghia gov nhin.................................................................................................................. 212

2.3 5

DiOu kiucn liny nhap dii' !ivu........................................................................................................................... 213

2

Ni.lf-* : i! f I!<': !

>'■>


6

r
2.4.1

Xu ly truy v an ............... ....................................

2.4.2

Xi> ly khdp

2.4.3

Sir dung truy van c o n ........................................................ ................................................................ .................. 230

2.4.4

Su dyng goc n h in ....................................................................... ............................................................................ 234

2.4.5

Xu* Jy thay d o i .......................... ........................................................................................................................... 235

2.4.6

Tong ket ve S Q L .............................................. .......................................... ...... ............... ................................. 237

. 2.5

.......................................................................................... .......... ....................................................... —......................22

Su dyng m o rong cua SQL.................................................................................................................... ............................. 246

2.5.1

SQL dugc nhung.................................................................................... ........................... ................. ................ 246

2.5.2

Thao tac dung con tro .................................................................................................................. .........................247

2.5.3

Thao tac khong dung con tr6 ................................................... ......................................................................... .251

2.6
3

.................................................................................. ....... 214

Bai t|p................................. ....................... ............................ ..................................................... r—.....................................253

Quan trj co s6 du lieu........................................................................... .............................................. ........................................257
Muc tieu ciia ch u an g ................................................................... ............... .................................................................. . . ...........257
3.1

Chuc nang va d£c trung cua he quan trj co so du* lieu (DBMS).................................... ..................... .................258

3.1.1

Vai tr6 cua D BM S........................................ ................................. .......................................................................258

3.1.2

C huc nang cua DBMS....................................................... ................. ,....................... .................................... 259

3.1.3

D§c trung cua DBM S.................................................................................................................................... ...261

3.1.4

Cac kieu DBMS.......................................................... :.........................................................................................266

3.2

4

Co so dir lieu phan b o ........................................................................ ............................................. ...................................268

3.2.1

D&c trung cua co so du lieu phan bo..................................................................... ........................ .............268

3 .2 2

Cau true cua co so du lieu phan b o .............................................................................................................. 270

3.2.3

Bq n h a dem cua may khach (client cach e)..................................................................................................270

3.2.4

Xac nhjjn (com m itm ent)........... ......................................................................................................................... 271

3.2.5

Ban sao .................................................... .................................................................................................................272

3.3

Cac bien phap duy tri tinh toan ven co so du lieu......................................................................................................273

3.4

Bai ta p ......................................................................................................................................................................................... 274

Cap nhat ve Cong right? Co so du litju.................................................................................................................................... 275

Myc tieu cua chuong ......................................................................................................................................................................... 275
(.;I6 >thit?n.............................................................................................................................................. .................................................276
•Li

Quan !y uit CSUL Io n ...........................................................

........................................ ................................................. 27b


7

5

ii d loi bai l§ p ...................................................................................................................................................................................... 284
5. i

Tra lai cho Quyen 4 Phan 2 Chuong i(Tong quan veco so du lieu ).................................... ............. .......................284

5.1.1

Danh sach d ip An................................................................................................................................................ 284

5.4.2

Ira loi va mo ta ..........................................................................................................................................................284

5.2

Tra lai bai t|p cho Quyen 4 Phan 2 Chuang 2 (Ngon ngu* c a so du li§u )............u............................................292

5.2.1

Danh s£ch dap an................................................................................................................................. ................... 292

5.2.2

Tra loi va mo ta......................................................................................................... ................................................292

5.3

Tr£ lai cho Quyen 4

Phan 2 Chuang 3 (Quan ly co so

du lieu)............................................................. 298

5.3.1

Danh sach dap an.................................................................................. .................................................................. 298

5.3.2

Dap an va mo

........................................................................................................................................................299

T ra aru ihuQt n gu .................................................................. ................. .................................................................................................. 301


9

Phan 1

Cong nghe Mang

Phan nay giai thich mpt cach he thong de cho nguoi hpc cong ngh£ mang Ian dau tien co the de dang thu dupe tri
thuc trong nhung linh v\rc nay. Phan nay bao gom cac chuong sau:

\
\

Chuong 1: Giao thuc va dieu khien viec truyen
Chuong 2: Ma hoa va truyen
Chuong 3: Mang (LAN va WAN)
Chuong 4: Thiet bi truyen thong va Phan mem mang


to

1 Cac giao thu»c va dieu khien truyen

M uc tieu cua chuong
Trong cac He thong mang sir dyng may tinh, truyen thong dupe thyc hien dya tren cac giao thuc chung. Kien
true m ang la can de x i c djnh va hieu chinh cac giao thuc nay. Khi viec truyen thong thyc te du*dieu khien truyen bao gom c&c giao thuc truyen khac nhau dupe sir dyng.
Chuong nay cung cap cho nguoi dpc kh£i niem chung ve kien true mang va y nghia cua no trong viec hpc ve cac
giao thuc dieu khien truyen.
1.

Hieu dupe sy can thiet cua kien true mang, chuan hoa, cac kieu kien true va cac chuan thyc te v.v..

2.

Thu dupe tong quan va hieu dupe cac kien true mang dien hinh, yi dy nhu OS! va TCP/IP, giao thuc
phan cap cua ch u n g , vai tro cua moi tang phan cap v.v..

3.

H qc ve die co che dieu khien va hieu dupe c&c giao thuc dieu khien truyen dien hinh, nhu "Dieu khien
lien ket phuong thuc co ban" va "thu tyc H P L C ".


11

Gioi thieu
Ket noi rnang mo da co nhieu lien bp ion cirng voi viec trai rong cua Internet va Intranet. Xay dung cac he thong
mang mo cho phep truyen thong voi cac co quan khac khong don gian la van de noi cac phan cung dirpc san xuat
tu ca?c nha may khac nhau qua phuong tien truyen.
Khi xay dyng cac h# thong mang, dieu khong the thieu dupe la phai thoa thuan tuan theo cac giao thuc truyen
thong de viec truyen thong dupe thuc hi£n. Cac giao thuc truyen thong thay doi cung voi cac he thong may tinh
va durdng truyen, va nhieu giao thirc khac nhau da dupe chap nh§n ca 6 Nhat ban va d nude ngoai, di tu cac kieu
nha cung cap nhat djnh toi cac kieu dirpc chuan hoa bdi cac to chuc cong cong. Cung vdi sy gia tang trong cac he
thong dupe noi v6i cac he thong mang khac, nhu Internet, kien true mang dang tro thanh ngay cang quan trpng
hon.
Cac giao thuc truyen thong
Giao thuc truyen thong 1^ mpt t§p cac quy tac tao kha nang cho truyen thong. Khi ban truyen thong bang di$n
thoai hoac thu tin, co mpt so cac quy tSc da dupe xac dinh trudc
ban phai tuan theo de tao kha n&ng truyen
thong. Ngupc lai, ban c6 the noi rang neu ca hai ben ton trpng cac quy tac thi viec truyen thong tin cay moi tro
nen co the du

Vi truy§n du* li£u cung bao gom truyen thong vdi cac ben khac (noi nhan du li£u dupe truyen) qua duong truyen,
cac quy tac nhat djnh (giao thuc truyen) de truyen thong duoc yeu cau va khi cac quy tac nay dupe tuan thu, moi
co the truyen thong tin cay dupe.
K ie n tru e m a n g

Kien true mang la cau true nen cua mang, va no x&c d|nh thiet ke he thong ve logic, khong chi ve cac giao thuc,
ma cdn la cac dang thuc thong di#p, c ic ma va phan cung. Tuy nhien, kien true mang liic ban dau co tinh chat la
d6ng kin trong hau h§'t cac trudng hpp. Bdi vi mpt so cac nha s&n xuat (nha che tao phan cung) xac djnh ra cac
kien true mang (nhu SNA cua IBM, v.v..) co the tao nen cac mang sd huu ri£ng cua hp, co nhieu mang khong c6
kh& n£ng lien noi vdi cac mang dua tren cac kien true mang khac.
Tren nen tang nay. To chuc tieu chuan quoc te ISO dS de nghj va chuan hoa cai gpi la kien true mang OSI (Lien
noi He thong md) nhu mpt kien true mang dupe chuan hoa quoc te, no dpc lap vdi cac yeu to cua nha san xuat.
Cho du khong la giao thuc chuan Quoc te, TCP/IP (Giao thuc dieu khien truyen/Giao thuc Internet), dupe sir
dyng nhu giao thuc chuan cho Internet, dupe sir dung rpng rai v& trd thanh chuan cong nghiep thuc te cho
truyen du lieu.
Theo tinh huong dupe neu dai arong d tren, trong chirang nay ban se hpc ve y nghia, chii djnh va dieu khong the
thieu dupe cua kien true mang thong qua viec hpc cac giao thirc truyen thong (chu yeu la OSI va TCP/IP).

1.1

Kien true mang

Theo djnh nghTa cua ) IS (Chuan Cong nghiep Nhat ban), "kien true mang" la "cau true logic va nguyen ly van
hanh cua h f thong mang". Tuy nhien, do la mpt djnh nghla rat triru tupng. Vay chung ta hay xem sir ra ddi cua
kien true mang de hieu dirpc y nghia ciia no. Rdi chung ta se di tit tong quan den giai thich cac cau phan chi tiet
cua kien true mang

2.7./

Bdi canh ra dai dia Kien true m ang

C ac hv’ th o n g m a n g d a u lie n la " L a ’: lu; ‘ h u n t; ta p tr u n g va o m a y c h u " { " lio s t- c c n tr u b y s te m s ’ ), co n g h ia la m ay
dm

\in

lijn h th ie i bj d a u ru n i ya ng oa i y i nao d u u i su d yn g.. 1m b h u o n g lhonv> ih u o jig ia h a n u san. xu a t m a v -c h ii

la d ie m cot ye u il'o n g vn;< \a y Ji.rng he ilinitj.- i .>» hr* l)t<>n)' K m ih ,m in'i i u iij; d in u; '. i y t h in g .ic t ii. in th u \'< m <,ir
yeu cau cua m o i u n g d u n g


12
Tuy nhien, da nay sinh ra nhung van de sau.
o

Trong trudng hpp cua "h$ thong may t£p trung vao may chu", rat kho de lap cau hinh lai hoac md rpng cac
hf? rhdng, tham chi trong moi trudng he thong cua cung mpt nha san xuat.

•

Voi vi£c tang do phuc tap va so hryng cac he thong, gia thanh phat trien lien quan den mang truyen thong
tra nen ngay cang Ion.

•

Khi can true phan mem tang dp phuc tap, phan mem truyen thong doi mat voi thach thuc doi quy mo de ho
tra cho so lupng ngav cang tang cac ket noi thiet bj dau cuoi.

•

Bien gidi giua phan cung va dieu khien truyen thong va cac chuc nang ung dyng da tro nen ma nh$t.

Phong trao giam quy mo da lam tSng toe viec chuyen doi tu "cac he thong t£p trung vao may chu'' sang "c a t he
thong phan bo'" va su can tiiiet de xay dyng mot moi trudng he thong nhieu nha cung cap su dyng he thong ma
tra thanh nhan to quan trong cho sy ra doi cua kien true rn$ng.
N hu mot van de thyc te' khuynh hudng cac he thong md da duyc tang toe bdi sy gia tang cua Internet tren quy
mo toan the giai, va dieu nay yeu cau cac may tinh co the duyc ket noi bat ke tai nha sdupe six dyng. Do dd, nguoi ta trong dpi rin g sy can thiet ve kien true mang,- mo ta cau true logic vh cac nguyen
ly v$n hanh cua cac he thong m$ng vk djnh nghia cac giao thuc truyen thong cho trao doi du lifu thyc se t&ng
han nua trong tuong lai.

1.1.2 N guyen tac chung vd cac chuan cua Kien true m ang

(1 )

Ki£n true m?ng l& gi?

Y nghia cua kien true m^ng da dupe da dpng tdi trong cac thu£t ngu truu tupng tren, va bay gip chung ta se xem
xet npi dung trong ckc thu£t ngu xac djnh han.
Kien true m^ng djnh nghia va phan loai toan bp cac chuc nSng (thiet bj noi va cac phirung phap dieu khien truy
nh|p, v.v..) can cho viec truyen du lieu. Them vao do, nd xkc djnh "cac giao thuc phan cap" tuong ung vdi moi
phan lo$i va xac djnh die giao thuc va giao dien giua cac tang cua giao thuc phan cap. Bang cach thiet l^p cau
true he thong qua sir dyng cac giao dien va giao thuc da xac djnh, nd t$o kha nang v§n h£nh cac he thong m?ng
mpt cach hieu qua.

(2 )

Many Logic

Trong kien true mang, toan bp cac yeu to vat ly cua ni?ng (thiet bi va chuong trinh, v.v..) dtrpc mo hinh hoa va cau
true hoa va xir ly nhu mot mang logic. D$c bi?t han, cac cau phan chinh cua m^ng logic la:
•

"n u t/' co nghia la phan cung, nhu cac may tinh va cac thiet bj xu ly truyen thong,

•

"lien ket, "co nghia la dudng truyen thong,

•

"xir ly," cd nghia la cac chuong trinh ung dyng.


ffivh J.7.1 Mutig logic
Myt'tg

Trong m^ng logic, cac mang con noi cac nut (cac may tinh, v.v..) lai dupe noi voi nhau boi cac thiet bj ket noi
mang (cac cong - gateways, v.v..) nhu da chi ra tren Hinh 1.1.1.

(3 )

Chuan hoa kien true mang

Viec chuan hoa kien true mang co cac ly>i ich sau.
•

Neu cau true la n\Qt, mpt h£ thong co the dupe xay dung b&ng cach thay doi giao di^ri, tham chi khi cac san
pham tir cac nha san xuat khac nhau dupe to hpp lai. Luc d£uy vi£e xay dung h? thong dupe dieu khien boi

nha san xuat, nhung vi£c chuan h6a kieh true mang da tao nen kha n2ng lam cho nguoi dung su dyng eac
san pham phu hop nhat. v6i inyc dich cua hy (xay dyng h£ thong nhieu nha s&n xuat).

•

Viec sir dyng h£ thong tuan theo cdc giao difn chuan lam cho vi§c phat trien, mo rpng va bao tri he thong de
dang hon.

•

Tham chi cac h£ thong dupe phat trien dQC lap co thede dang dupe tich hpp, tao ra hieu
trong vi£c xay dyng c ic he thong phan bo".

•

Toan mang co the dupe xir ly mpt each logic: Vi dy, kieu he thong mang la gi khong quan trpng,no se khong
£nh huong toi cau true, v.v..

quaIon, dac biet

Hinh 1.1.1 so sanh viec sir dyng kien true m^ng chuan dien hinh (OS1) voi kieu khong chuan
Hirth 1.1.2 Su dung OSI /khong sir dung OSl

GW

Kirn tun »>■+*>»
< ua

Ki£n true m*ng
cua cOiig I) A

KhNi uitc m*n^
GW G• & * * /
iiuicOf)# iy A — GW

t y ft j *

r------ t

( Kien in k

ia wCvng l y

0

J

C.-ui i4>ii ihu>ln vl6smiiu c
j Ki^n true fttyng
U'U

4v’Ofig ly B

O Sl — 1

Ktfn (rue mangl
CiiA
I) C j

Co ih* lru>cn ilMtag tik»

Nlur minh lu:u trong lnnh 1.1.2, vi(*c truyen (hong khong the thuc hien dupe neu khong co viec chuyen doi
&kh>ihuv, tru pm Mr Ji.mj; kscn true cluuwi nhu <.).->!.

l«.il


14

1.1,3

Cac kieu kien true m ang

Co mot so Strong 16n cac kien true mang, bao gom cac kien true rieng cua nha san xuat (SNA cua IBM, v.v.), cao
kien true dtrg»c chuan hoa quoc te, cung nhu cac chuan thuc te, Trong so' do, cac kien true mang dien hinh la OSI
(Lien noi he thong m d) va TCP/IP (Giao thuc dieu khien truyen/CJiao thuc Internet).
Hinh 1.1.1 dua ra cac kien true mang khac nhau.
Hinh 1.13 Cac kieu kien true mang
p - <OS!>
NA m a
Ki£n true m^ng (NA)

NA phu hgp
v6i nh& cung
cap cm th&

<TCPyiP>
- SNA (IBM)
- DECnet (DEC)

IPX/SPX (Nowell)
' Apple Talk (Apple
Computers)

1.1.4

Cac chuan thuc te(D e Facto )

Cac kien true mang bao gom mQt so kien true dien hinh nhu TCP/IP va OSI. Tuy nhien, khong giong nhu OSI,
TCP/iP khong phai la kien true dirge thiet lap boi ISO ho$e boi mQt to chuc chuan hoa tuong tu*. TCP/IP duoc sir
d\mg cho mang lcm nhat the gidi, Internet, va no cung la mQt dac trung chuan ciia UNIX, he dieu hanh chinh cho
c&c m£y tram v& cac m iy chu. Ndi c^ch khac, no da tro thanh mQt chuan cong nghiep thy-c te.
Mol quan he giua TCP/IP va OSI duQe giAi thich trong myc 1.3 TCP/IP.

1.1.5

(1)

To po m qvg va cac phucmg phap ket noi

To po mang (ciic cau hinh ket noi cua m?ng)

Viec ket noi cac may tinh va cac thiet b\ dau cuoi, v.v.. qua duong truyen tao nen kha nang xay dyng nhieu loai
cau hinh mang khac nhau, tuong ung voi quy mo va myc dich sir dyng.
Cac cau hinh mang dien hinh duoc chi ra tren hinh 1.1.4.


Kieu Vdng

K ie u v o n g la mQt cau h in h tro n g d o cac n u t (cac m ay tin h , v.v..) d u p e n o i th e o mQt v o n g k h e p k in d u o n g tru y e n .
D u o n g tru y e n tro n g lo<=ti cau h in h m a n g na y n g an va de d ie u kh ie n . N huQ C d ie m la n e u c h i n ip t n u t h o n g , co the
g a y a n h h u d n g d e n toan m ang.

(2)

Kieu Mdt Iu ai

Trong kieu mat hrdi, hai hoac nhieu dtrimg dan toi moi mit sau cho cau true tong the ia m o t mang luoi. Dieu nay
co nghia la th a m chi neu mot nut hong, nut nay 16 tin*' du«,» ho qua bang each tim duong (lua chQn duong
tru y e n ), co n g h ia ra n g d o On cay cua man}> la ra t tao.

(3)

Kieu Sau

i ’r o n ^ k ie u btiu, m o i n u t d u o c not \ u l m g t n u t tr u u ^ ta in (bg la p kt-l d u o n g , v v .) tio n g m ot u iu h in h d a n g .'.»ao.


*5

Cho du mpt isul hong, no se khong lam anh huong den toan bp he thong, nhung neu nut trung tam hong, toan
filing se khortg lam viec niry.

With 1.1.i Td po (topology) mang

®

Kidu Bus

Trang kieu Bus, tat ca cac nut dupe noi tai dudng truyen chung.
Cau h'rnh bus de dang them ho$c loai bo cac nut ma khong lam iinh hu6ng tai toan bp he thong va dong thoi
cung tiet kiem. Tuy nhien khi co nhieu nut va iupng truyen tin 16n (lupmg thong tin can truyen trong 1 khoang
thoi gian xac djnh) t£ng len, sy dyng dp dCr lieu co the xay ra tren duong truyen chung va hieu qua truyen (thong
lupeng) co the gism dpt ngpt.

(§)

Kieu Cay

Trong kieu cay mpt vai cac nut
(cascade).

condupe noi toi nut cha. Cau hmh nay cung dupe gpi la ket noi xep tang

Gan day, cau hinh nay da tro nen dupe chap nhan rpng rai hon, nhung neu nut cha hoat dpng ioac choac, no se
jam anh htrcmg tai toan bp cac nut con.

(2)

Cac phtfdng phap noi dtfdng (Cac phutfng phap de ket noi cac m$ng)

De de hieu, chung ta se su dung mpt mong don gian vai mpt may tinh trung tain dtrpc noi bai mpt vai cac thiet bj
dau cuoi qua duong truyen nhu mpt v» dy dun gian de giai thich cac phuong phap ket noi cac mang.
Co ba phuong phap ket noi dien hinh duyc bit dpng tuong ung tot nhat voi khoang each truyen va iupng du* lieu,
v.v Chung la:
*

Ket noi diem toi diem (l\»inl tn point)

*

K e t n o i da d ie m ( M u ltip o in t

»

Ket !'iOi rhuyen nuu/h (’nvtLlicti)

0 .i

tii'i noi iticin i in i i i d n

i

<

in p o tu ii

i l l . M g K f t I'.'.)! d l t ’ US It J * u i t ' l l i , »itui\ t i l ! 1!'. >..tm,»v

{ *'*.M H I ' j '

IIH.'1. J o | \ >.*! H".N ( l u r t I 1* d . ’lU ‘ VI*’ I

‘.1

I g ft s * \ «*i 'i I t i ' . i c


i6

bao.
Cau hinh nay la thich hpp neu xay ra viqc truyen lirpng du lieu Ian giua hai diem dupe yeu cau, nhung khdrg
kinh te neu lucmg truyen du lieu la khong du ion. Khi so lupng cua cac thiet bj dau cuoi tang len, thi cung tirr.g
ay ttirang truyen cung se dupe lf«em vao.
H in h

1.3.5 K e t

n o i d ie m t a i d ie m

Tb*6t bj d&u cudi

©

Ket noi da diem (Multipoint) (multi-drop system)

Trong ket noi da diem, nhieu thiet bj phan nhanh duoc noi lien tiep toi cung mpt dudng truyen. Sau d6, cac thiet
bj dau cuoi duoc noi t6i thiet bi phan nhanh
Cau hinh nay cho phep tao nen mpt mang re hon mang sir dyng cau hinh diem-tcri-diem khi ma khoang cach
truyen dai va lupng truyen du lieu it. Tuy nhien, vi dimg chung ducmg truyen chinh, cac thiet bj dau cuoi khac
ph&i chd trong khi mQt thiet bi dau cuoi dang truyen du* lieu.
H in h

1. 1.6 C a u

h in h d a d ie m

Tokyo

Nagoya
nhAnh

Kumamoto
1 nftaohl

M6y c U i

S
TN& bj
dilu cudi

®

Thtft b|
ddu cudi

Ket ndi tap trung

Trong ket noi tap trung, duong truyen dupe noi toi mQt bQ tap trung (concentrator), bQ tap trung nay dupe noi toi
mQt may chu qua dudng truyen toe do cao. (hinh 11 -7)
Day co the la cung mQt phuong phap truyen thong nhu da dupe sir dyng trong cau hinh diem-toi-diem, trong do
moi thiet bj dau cuoi dupe noi rieng le toi may chu. Tuy nhien, gia thanh cua duong thue bao nho hon truong
hpp cau hinh diem-tdi-diem, cho phep xay dung mpt mang rat kinh te ma chu y nhieu den dung lupng cua
dudng truyen giua may chu va bp tap trung. Noi each khac, tai dir lieu tu moi thiet bj dau cuoi toi bp tap trung
can ph^i dupe tinh tdi khi thiet keinang.
Hinh 1.1.7Cau hinh ket not tap trung

Thi6t.b|.d£u cu6i
f* 3 ] HaKota

Tokyo

FukuCjkd

ap k6sp'-I Oud7ii16 cao
May uJtu
1

'

‘ Nagasaki
□

Kumamoto

I 11 Miyazaki


17

1.2

OSI - chuan hoa cho giao fhu’c truyen thong

Muc nav neu mpt tone quan ve kien true mang da dupe chuan hoa quoc te OSI (I.ien noi cac he thong mo) duoc
thiet lap boi ISO (to chuc tieu chuan quoc te) va giai thich ve vai tro cua cac tang cua mo h'rnh nay va quan he voi
lieu de' v.v..

1.2.1 Tong quern ve G Sl

(1)

OSI nhiT m gt chuan quoc te

OSI la mpt chuan quoc te dirge thiet l£p dau tien boi iSO va ITU-TS (Hiep hoi vien thong quoc te - Tieu ban chuan
hoa vien thong quoc te). Noi cach khac. OSI la mot kien true m?ng chuan quoc te va dpc Up voi nha san xuat.

(2)

Cac vai trd cua OSI

Vai tro cua OSI duoc neu d$i cuong tren hinh 1-2-1.
Chung ta hay gia thiet rang nguoi Nh§t chi co the noi tieng Nh|t va nguoi Due chi co the noi tieng Due. Neu hai

ngu6i nay lam viec voi nhau, lam the nao de hp c6 the thye hien truyen thong va dam tho^i v6i nhau?
Hinh 1.2.1 Truyen thdng giua ngudi N hat va ngudi Due

<OSl>

Tidng Anh, ngfin ngif qudc i6
diwc sis dung giua cdc ph&n dich vien
Viec phien djch phai duoc thuc hien nhu mot cau noi va cho phep truyen thong giua hai ben. Tieng Anh hoac
mot ngon ngu quoc te chung duoc sir dung de phien djch. Vai tro cua ngon ngu* chung la vai tro ciia OSI trong
kien true m$ng.
N6i mpt cach khac, )o?i phan mem nao dang ch?y tren m?ng khong phai la van de va bat ke lo?i du lipu nao dang
dupe truyen, viec truyen thong du lieu khong co van de van c6 the dupe thuc hien mpt each binh thuong tren
mang luan thu OSI

(3)

Giao thu’c phan cap

Khi mpt so mang khac nhau duyc noi lai, cac chuc nang truyen thong tru nen phuc tap, da dang va roi ram. Vice
nhom cac chuc nang thanh mpt giao thuc phan cap tao dien kien thuijin lai cho viec c6 dupe mpt tong quan. OSI
ra doi voi y tuong nay, va mo hinh OS! gom co 7 tang Noi dung tlujc r>u cua 7 tang (phan cap giao thuc) dupe
giai thich chi tiet trong phan 1.2.2
Khi tong ket cac cai loi >«>.*. phan tang, >hung t,i nhan ituo«' dit-m -..ai
■vit’l-i V

'Vi I

ivj i h u c c u a rnut «»>ng hi lhd>’_ do», d i f i i ytv..; k l u m g a n h .hi/wiig

,'ijig ViCC triCii klt.lt i!«j«'C lii'tlC i'liCi'i i.i ch1daii)'

n cnc. wauu t h u c .k h a c . * iV nv.hia-


18
•

Cac tang d m ac thap hon co the dugc xir iy nhu hpp den, co nghia ta cac chuc nang truyen thong phuc t?p co
the dugc don gian hoa.

Viec phan tang la cut- ky quan trong trong kien true m^ng, bdi vi luon can can nhac xem xet de bao dam:
•

•

Tinh ingang bang
Cac giao thue dugc xac dmh giua ding cac tang.
T in h d $ c la p

Th|m chi neu mot tang bj thay doi, dieu nay khong lam anh hudng toi cac tang khac.
Trong mo hinh tham chieu c a b^n OSI va cac mo hinh mo khac, moi tang dugc trim tugng hoa la "tang thu N" va
tat ck cac khai ni£m va quan he cua no vdi mpt trong cac tang khac dugc hieu ro mQt cach logic

(4)

Moi quan h§ git/a cac tang cao hdn va cac tang thap hdn

De thuc hien truyen thong giua cac he thong md, can co cac module chuc nang, nhu cac chuong trinh truyen
thong dugc ggi la cac "th yc the", va hai hoac nhieu thyc the ton tai trong moi tang N. Moi quan he giua tang N
va cac tang d muc cao horn va thap hon dugc chi ra tren Hinh 1.2.2.
Hinh 1.2.2 Mfii quatt h? giua tang N va cac tang 6 muc cao han vd thap hon

L d p (N M )

Djch vu (N)
(1)

(3)

(4)

Ldp(N)

Thyc
t ip (N)

(2 )

Thyfc tb£
itip (N)

<5>
Ldp (N - 1 )
Djch vv (N * 1)

Sir dyng hinh 1.2.2, moi quan h£ giua cac tang khac nhau dugc giai thich van tat nhu sau.
•

Djch vu ma Lang (N) cung cap cho tang tren (N+l) dugc ggi ta djch vy (N). Binh thudng, tang (N) tich
hgp cac djch vy ma no nhan dugc tu tang (N -l) vdi cac chuc nang rieng cua no va cung cap dieu nay
dudi dang djch vy (N).

•

Giao thuc dugc su dyng giua cac thuc the (N) dugc ggi la giao thuc (N).

•

Hanh ddng (djch vy) thyc hien chuc nang trao doi thong tin giua tang (N) va cac tang cao hon va thap
hon, cd nghia hanh dgng nhu giao dien giua cac tang, dugc ggi la djch vy nguyen thuy (N). Cd 4 djch vy
nguyen thuy, nhu "veu cau" ("request").

•

Diem truy nhap giua tang nhan djch vy (N) va tang (N) dirge ggi la Diem truy nhap djch vy (N) (SAP).

•

Kenh truyen thong logic dirge sir dyng de trao doi du lieu giira cac thyc the (N) dirge ggi la ket noi (N).

1.2.2 Md hinh tham chieu OSI ca ban

(1 )

Cau true

Hinh ! 2 3 mioh hoaihi ra cau intf nia md hinh th.im chieu OS! ct/bon


19

ffinh 1.2.3 MS hinh tham chieu OS! cur ban

!

Cuuy c ip cac djch vy truyfen thong cart cho c ic tVn-j dyng

r&ng i>ng dung

I

T&no trinh b&v

■ T ing mu* 6

TSng Uiu- /

Bi^u dien cSO* lieu. ujch v i anh

Tin y phien

1 Tanp

Q uin ly S6i thoai, di^u khidn dt£m o6ng bo. v.v

5

dang '.hue
!

Ting v$n chuyen

;

T in a thu14

B io daiii truytn d iv li§u git>a d iu cu6s {wul-to-end), v.v.

T^ny m^ng

i

T in g u u r i

Cac ch!>c n in # iir« d^ong. v.v

T&nq Ii6n k£t dl> ii£u

'

T in g thu 2

8 io d im v$n chuyen dt> li$u giua cac h$ th6ng iin can, k iim s o it I6i, v.v..

U n g V it ly

;

T in g thi> 1

(j ndi v i cac ch in n6i, phuong ti§n truy^ri. v.v..

Bay tang nay co the duoc phan chia thanh cac tang cao hon va thap hum nhu* dupe chi ra nhu sau.
C ac tang 6 muc cao hon tu tang ung dyng toi tang phien cung cap cac chuc nang cua djch vy truyen thong.
C ac tang 6 muc thap hon tu* tang van chuyen toi tang vat ly: Cac chuc nang truyen du lieu.
Cac tang 6 muc thap hon chu yeu bao dam vi«?c van chuyen du li£u c6 chat luong cao, va cac tang 6 muc cao hon
sir dyng cac chu*c ning cua tang thap hon de cung cap cac dich vy cho cac ung dung.

(2 )

Vai tro cua moi tang

(D

Tang ung dyng (tang thir 7)

Tang ung dyng la tang thu 7 va la muc cao nhat va xu* ly chii yeu bing viec cung cap cac djch vu nhu:
FTAM (Truy nhgp va Quan ly truyen t£p - File Transfer Access and Management)
RDA (Truy nh|p co so du* lieu tu xa* Remote Database Access)
VT (Dau cuoi ao - Virtual Terminal)
Hinh 12.4 Cac chuc tt&ng cht'nh cua tang ihtg d\tH%

.. -R A M - --r

Truy n h ip v i q u in ly truyfen t$p

RDA

1 Truy n h ip ay sd du* li#u tu- xa

VT

*

TP

i

Xu* ly v£n giao t ic

MHS

;

H£ th6nq xu* ly thong b io

D iu cu6i io

©Tang trinh bay (tang thu 6)
Tang trinh bay la mpt muc 6 duoi tang ung dyng va thuc hien chuyen doi cac d$ng thirc dir lieu, v.v de dam bao
truyen hieu qua cac loai thong tin khac nhau. Trong tang img dung 6 muc tren, viec mo ta thuong duyc thyc hi|n
bing cach dung he thong bieu dien duoc gqua gi ua cac mang, cii phap triru tuong duoc djch thanh dang thirc du li£u (duyc gyi la "cu phap truyen") trong
tang trinh bay, trong do anh xa cu phap triru tugng va cu phap truyen, v.v.. duyc thyc hien. Cac chuc nang ciia
tang trinh bay cho ph£p tang ung dyng cung cap cac djch vy ma khong can biet den viec giai ma dtr lieu va bieu
dien v£t ly cua may tinh doi tac khac.
Hinh

1.2 .5

Dich gitfu cu phap trim tuyntg va

a t

phap truyen
(H $

Ih d n g

P )

C<i p/»«pVv*J t;/pr>g

jCup>Mptaw

Ting i/ng dyng

Chuyen <3^

Ting trinh b«ty chuyen ctf!>i
va anh xa c j phap t/ifti tuong
vi cu phap truyen

j Cu pftip tfw/fr)
;
0101110111 •
-

=

f

{H$ Ihdng Q)

-

^huy£n ddi
COpfvJjp
0101110111* *
y

j
i

(2)

Tang phien {tang thu 5)

Tang phien \h mpt muc 6 dudi tang trinh bay va thuc hien chu yeu "quan ly doi tho$i". Viec quan ly doi tho3i
dieu khien va quan ly luong du lieu giua cac irng dung va cac hf thong bang cach sir dung kha nang truyen dir
lieu dau cuoi-dau cuoi do tang vjn chuyen cung cap.
Phucmg thuc truyen thong co the dupe d£t mpt cach tuy y. Trong trudng hop truyen thong binh thudng (truyen
E-mail, v.v..),vi dy sii dyng truyen ban cong (mot chieu t$i mot thdi diem). Trong trudng hop truyen thong hai
chieu dong thdi (nhu trong cac he thong hpi nghj video, v.v..)/ truyen song cong (ca hai chieu dong thdi) duoc su
dyng. Bang cach thiet l£p diem dong bo, viec truyen co the dupe thuc hien l$i tir diem dong bp trong trudng hpp
truyen hong do bat c& nguyen nhan nao trong khi truyen du lieu, Thdi gian mat di vi v§y co the dupe giam toi
thieu.
Hinh 1-2-6 Diem dong bp
BAtdiu

• 4 --------

Chuong \
D & tt ddng bO phu

E>i£mddng t>0chinh
fti$m chf iFong uiftmg

to oo

Mi phvc l?i vijc

vi£c iruy£n vdi t\f fciiip 60

cia tic tfi&n

bQ

---------------

Lk

Chutmg 3

DWfm
I
jDi&n ding

difoh

Chuong9

1
®

Tang van chuyen (tang th u 4)

Tang v|n chuyen 1& mpt muc d dudi tang phien va chuc nang cua no la de bao dam chat lupng truyen du lieu
giua dau cuoi cua he thong (end-to-end). Vi v$y, neu chat lupng cua cac djch vy dupe cung cap bdi tang dudi la
khong day du, tang v£n chuyen se bu chat lupng xau b&ng cach phdt hien vh khoi phuc 16i phy.

®

Tang mang ta n g thvc3)

Tang mang la mpt muc d dudi tang v§n chuyen va lien quan chu yeu tdi viec chpn dudng (routing) va chuyen
m?ch. Khuyen cao X.25 cua ITU-T (xem phan 1.5.2 ve lo$t X) ve giao thuc muc goi dupe biet den nhieu.


21
H inh 1 - 2-7 Chuc n an g tint ducmg

:

Ofc <3»&ii l6i dkli trung khi lim iSufrng

Trong khi tang v|n chuyen o tren bao dam truyen di> lieu giua dau cuoi cua he thong, tang nay lien quan den
viec lya chgn duong di phu hpp nhat de bao dam viec truyen du lieu "trong suot".

@

Tdng lien ket dir li?u (tang 2)

Tang lien ket du lieu la mpt muc 6 dudi tang van chuyen va dam bao viec truyen du lieu trong suot va khong co
loi.
Noi chung, cac vai tro cua tang lien ket du lieu bao gom dieu khien truyen, nhu HDLC (dieu khien lien ket du
lieu 6 muc cao), thiet l§p ket lien ket noi du lieu, dieu khien loi (CRC (kiem tra vong du thua)), ma hoa, v.v..(Chi
tiet ve cac thu tyc di£u khien truyen, xem phan 1.6 Dieu khien truyen.)
Trong m$ng LAN (M$ng cue bp), tang nay cung lien quan den di£u khien truy nh§p, nhu CSMA/CD (da truy
nhap sir dyng song mang/phat hien dyng dp) va chuyen th^ bai, va dieu khien lien ket logic, nhu LLC (dieu
khien lien ket logic), v.v..

(6)

Tdng vat ly (tdng thu nhat)

Tang v^t ly la mpt muc 6 duoi tang lien ket du- lieu va truyen cac tin hieu dien ("0" va "1") sir dung phuong tien
truyen (cap xo3n ho$c dong tri,ic, cap quang, v.v.)
Mpt so cac giao dien trong thyc te DCE (Thiet b\ dau cuoi mach dir Ji£u) v& DTE (T hiet bj dau cuoi dir lieu) la:
Loat chuan X cua ITU-T: X.21 va nhung cai khac; xac djnh hinh dang o noi va bdng chan,..
Lo$t V: V.24 va nhung cai khac, xac djnh modem, v.v.. sir dung cho dirong tuong ty (Analog)
ISDN (Mang tich hyp dich vu so) giao dien dau cuoi loo 1 1 xai djnh TA (Bp thich ung dau cuoi), v.v .
CKi tiet horn ve cac giao dien, xem phan \3
1.2.3

Cac thu luc truxfcn thou# tro it# ( ) SI

.H in h 1 -? H so sanh.C IS!, v o i -c.vr h i H i i ' < - ! u :h-^ni ct m oi o tn i.' • { y N h a t bdn va m ot 't v‘ h ik k i i^o a i.

Iltfth t'/.-X < ‘i' $ <‘ll>

h

I l/l llJMV; 111


22

/f Cat;
rat; 4ai
4ai lit**
snrt ph3un|

/vi cAc. ss
^ duiic
dtfv* gin
if iCn {
ly nth 5

J

<oa>

rn&u roa coftg iy
HHI B v& r.uuig m iii
ldi cha tjch cOns

&l ilL'U vUU
cOng ly A
a
( \
||

Ting irinh b iy

Tl^ng Anh

j\

Nguta pbifcn djch
ltgs\g ai)}) gilTd

nt

Ting vSn chuyen

ling mang
T&ig lien k£i

dt) li£u

aoa
□□□

y|
C Ij

5 8
> u
2
NhAn viAii buu
di£n chuyen hang S ' 2

NhAn h&ng tur
nguoi dua bang

tdi ngufo nh^ii
Hang h fo cftuylii til eOfig ly
A tdi btfu ditn

Hang h6* duoc van chuyen
qua Amsterdam

□ DO

H iog hfc* ilw^c

o o o mang tir buu dȣn
tdi tdng ly B
Bu6c *i£p theo chuy& i idti
sftii bay Rome

"3TMumg ngt/oi phu:
vMchuyen bay
S Iv y chuyen bay cfa in i n n
I j u*kl» nhi^m cho
If \l ! /cJl*u

^ iOfi AiiftKiikm

T in g v$t iy

Ngudi

\ jL Ngudi phk*> dich djch
j f i C r tȣng anh sang li&vg y

*+■ eOna ty A v& cOnk iy B
T in g piiten

ra* nhanh /

V
f^t^Tcfiuin"bT”

Nguori c IhiI h bi
Tfcig «mg iiyug

S<

C 6ag ty ii
iy)

/

(/ CkC
ph&tj Uc’n !

j*

^ c h o d in khi tdi R
Trong may bay

Trong may ba)1

Owii cung u)i sin bay
Rome

Nhitng ngufri
f 11 11
v“ chu>*n
i i j i »»y

m lo^n
Truog miiy bay

1

Khi truyen thong dupe thyc hi£n su dyng OSI trong thyc te' cac thu tyc sau duyc thyc hien.
1.

Khi yeu cau truyen thong phat ra, kenh truyen thong dupe du
2.

Khi du lieu dupe chuyen qua m6i tang t$i ben giri, tieu de (cac thong tin dieu khien) dirge gan them

vao vai du- ii£u cua ngu6 i dung trudc khi du lieu dupe gui di..
3.

Khi du lieu duac chuyen qua moi tang 6 ben nhan , tieu de du
4.

Khi viec truyen du lieu diryc thyc hien xong, kenh truyen thong dug»c dong l$i (ket noi bj ngat).

5.

Cac tai nguyen truyen thong dupe giai phong va qua trinh xir ly d uac hoan thanh.

Cac tieu de duac them vao bai tang (N) duac gpi la tang thong tin dieu khien giao thuc PCI tang (N), va dir lieu
cua ngir6i dung tang (N) dugrc ggi la dan vj du lieu djch vy SDU tang (N). Dir lieu gQp ca hai phan duac gpi PDU
tang (N) (dan vi du lieu giao thuc). C6 nghia PDU tang (N) d u g c ho try bdi SDU tang (N -l) (Hinh 1-2-9).

H in h 7-2 -4 M o i ijmut h £ g iin t c a c tieu tie tui «n c tang


23

PDU : Dun vi dd lidu gian link'
SDU : £kai vj dH li^u djch vy
P C I : TUAng tin li£m so4l giaoth&r

1.3 TCP/IP - chuan thuc te cho giao thuc truyen thong
TCP/IP da trd thanh mpt giao thuc chuan thvrc te cho m^ng rpng nhat tren the gi6 i, tire la Internet. Myc nay clira
ra mpt tong quan va giai thich giao thuc phan cap va vai tro cua moi tang cua giao thuc nay trong khi so sanh no
voi mo hinh OSI.

1.3.1

(1)

Tong quan ve TCP/IP

TCP/IP I* gi?

TCP/IP (Giao thuc dieu khien truyen/Giao thuc Internet - Transmission Control Protocol/Internet Protocol) da tra
thanh giao thuc chuan cho Internet. Do sy lan rpng cua Internet/TCP/iP da tro thanh giao thuc mang chuan thuc
te. Co moi quan he m§t thiet giira TCP/IP va Internet, va boi canh ljch sir cho dieu nay duoc giai thich chi tiet
trong myc 3.2.t. Boi canh Ljch Sir ciia viec phai trien Internet.
TCP/IP dupe phat trier, nhu nipt phan cua ARPANET (se giai thich sau) trong nhung nam 1970, va la mpt chong
cac giao thirc linh ho$t bao d&m dp tin cgy cao va viec truyen toe dp cao. Chong cac giao thirc nay bao gom "cac
giao thirc TCP" v& "cdc giao thirc IP", nhung thirdng giao thirc TCP/IP dupe xem nhir cac giao thirc xac djnh

phuong thuc truyen thong duyc sir dyng tren Internet (doi khi n6 c6n dupe gpi lh "kten true giao thirc TCP/IP"
hoac "He giao thirc TCP/IP").

(2)

Giao ihtirc phan cap

Giong nhir mo hinh OSI, TCP/IP ciing co giao thire phan cap. Ve ea ban, no duue can true tir 4 tang sau voi moi
tang chua mot so giao thuc (giao thirc phan cap).
fang irng dung
Panr, v.’tii i lutycn


*4

So sanh giua OSI va TCP/IP dupe chi ra d hinh i .3.1.
llin h 1.3.1 So san k cac kien true phan ra p gum TCP/IP vu OSI
< m hinh tham cH6u OSI >

<TCP/fP>

SMTP
POP3

DHCP

NFS

SNMP

FTP

HTTP

NTPV2

CMOT

NMTP

ONS

OSS

XDR

MiB 2

TELNET

Ting thCr 1
l a/ig u n g d y n g

T in g ting dyng
T i n g IhtifS
T d n g trinh b a y

[ SMfi

Ting liiCir 5

Ting ph#n
T ln g t f v jr 4
T in g v$n chu yen

XOR

MI6 2

Mi ME

Socket

RPC

NETBIOS

Ting v$n chuyen
(TCP)

TCP

UOP

NfttWate/lP

T i n g In tern et

»P

RIP

08PF

PPP

SUP

Ting thCT3
T in g m $ng

(IP )

Lap LLC

ring ttn/2

Ting
H6r k&

d£rH$u

T in g
giao dten m$ng

L 6 p M AC

IEEE 602.3
CSMA/CD
1 0 0 BASE«T

■is e e a r e 5
TcfttfeCg
4 ,1 6 M b {*

IEEE 802.12
lOM&AnyLM
100 Mbp*

iTlkTS
ATM Forum
ATM

ANSI X 3T I2
FOCK
100 M ttt*

U xafT ak
23Q-4 kbps

Triln khai c6c 4Utog truyln th6ng nhtrcAp
xoln ddi, cap d6ng true. cap qua^g v.v...
d i truvln chu& bit______________________

T i n g t h i f n h lt
T i n g v $ t ty

TCP va IP deu la c i c giao thuc quan trpng, moi giao thuc deu c6 die chuc n^ng sau:
•

TCP (Gao thuc v?n chuyen; phuong thuc hudng ket noi) * bao dam dp tin cay cao.

•

IP (Giao thuc Internet; phuong thuc phi ket noi)« bao dam truyen du lieu toe do cao.

Cac phuong thuc hudng ket noi va khong ket noi duoc giai thich ngan gpn nhu sau.

CD

Phuong thuc hu&ng ket noi (TCP)

Phuong thuc hudng ket noi yeu cau ket noi true tiep (kenh Logic) dupe thiet lap giua ngudi gui va ngudi nhfin
trudc khi du lieu dugc truyen. Du* lieu duoc truyen qua kenh nay di den thiet bj dich cuoi. Khi viec truyen dupe
hoan thanh, ket noi bj n g lt Viec thiet lap ket noi lam phat sinh vi§c truyen thong co dp tin cay cao.
C£c hofct dpng dupe chi ra d Hinh 1.3.2, bang viec dung dien thoai lam vi dy.
Hinh 1.3.2 liinlt litth hifthtg k it ndi (di$n

tliO Q i)

\

(1) Quay *5 * >K*i ri6i •>tdc 06i tev kfiic *uat hl$n \j^-y
D ic n o

f

d

aCDO

9!

)
|

Ket

T

Ony A

d)

Mw

<Ttoel l$p ket n6i>

RClAChiOj

x

u
r>oi

1

- T

Khdng k£l ndi
Ket noi doge Ket thuc

Phuong thuc p h i ket noi (IP)

P hm xn g th u c p h i k d noi i>*> qua su

1

1'ii«*f k ip k c-{ noi tru e ne p va v»ec d a n h ken h iru y e ri thi»n^ *r«« « ‘ k h i div !>eu

d u o c tru y e n , cd n g h id t i n g k h o n g cd j u d a m bao la d u liv u si* td i n o i n h a n . M a t khac, no tau nen k h a iu \n g tru y e n
d ir heu toe d p cao. V i vay, d ie u k ie n tru o c trm i de sir di.4ii}' ph u< m g th u c pha ket n o i ia v u v i r l ■y •:»* th o n ^ p h a i
d u o c th u c h ie n tre n d u o n g tru y e n co d o tin cay

c m

* de la m tang xac suat diV lie u td i d iro c no t n ln n