Τεχνολογία Δικτύων Επικοινωνιών

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K. APBANITH . KOYBA . OYTIO

TEXNOOIAIKTYN EIKOINNIN

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TOMEA HEKTPONIKN

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EIMEEIA EKOH O

HEKTPONIKH EEEPAIA KEIMENOY M

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XEIAMO EYOY & POEKTYH BIBIOYYNEH

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AIAIKO INTITOYTO

E Y HEKTPONIKN,

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KEAAIO 1 APXE IKTYN EIKOINNIN ............................................................................................................................... 9 ............................................................................................................................................ 10

1.1 .................................................... 101.2 H ................................................................. 141.3 .............................................................................................. 141.4 ...................................................................................................... 191.5 .................................................................................................................. 21

1.5.1 ................................................................................................. 211.5.2 ....................................................................................................... 241.5.3 ......................................... 261.5.4 O ............................................................................. 26

................................................................................................. 26` ......................................................................................................... 27

1.6 ............................................................................................................... 291.7 .................................................................................. 311.8 OSI ......................................................................................................................... 35

1.8.1 OSI ............................................................................................. 37 (Application layer) ..................................................................... 37 (Presentation layer) ............................................................... 37 (Session layer) ............................................................................... 37 (Transport layer) ....................................................................... 38 (Network layer) .............................................................................. 38 (Data link layer) ......................................................... 39 (Physical layer) ................................................................................ 39

1.9 ............................................... 401.9.1 ................................................................................................................ 401.9.2 ............................................................................................... 411.9.3 LAN WAN ................................................................................................. 42

1.10 .................................................................................................................................. 431.10.1 ....................................................................................................... 431.10.2 O ........................................................................................... 44

ISO (International Standards Organization) ................................................................ 44ITU (International Telecommunication Union ) ........................................................... 44IETF (Internet Engineering Task Force) ........................................................................ 45IAB (Internet Architecture Board) ................................................................................ 45ETSI (European Telecommunications Standards Institute) ........................................... 45O ( O ) ........................................................... 46

1.11 ......................................................................................... 46 ................................................................................................................................. 47 - ......................................................................................................................... 47 ...................................................................................................................................... 50

KEAAIO 2 EIKOINNIE EOMENN ............................................................................................................................... 51 ............................................................................................................................................ 52

2.1 ............................................. 522.1.1 , ............ 54

, ..................................................................... 572.2 ........................................................................................................ 58

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4

2.3 ............................................................... 602.3.1 .................................................... 602.3.2 ............................................ 61

2.4 ........................................................................................... 642.4.1 ................................................................................................ 65

Nyquist ( ) ............................................................... 65 Shannon ( ) ................................................................... 66

2.5 .................................................................................................. 672.5.1 bit .................................................................................................... 672.5.2 ....................................................................................... 672.5.3 .................................................................................. 68

................................................................................................................................. 69 - ......................................................................................................................... 69 ...................................................................................................................................... 70

KEAAIO 3 MEA METAOH .............................................................................................................................. 71 ............................................................................................................................................ 72

3.1 ..................................................................................................................... 723.1.1 ......................................................................................... 72

........................................................................................................ 73O ................................................................................................. 73 O ............................................................................................. 74

3.1.2 ........................................................................................ 76 ............................................................................... 77 ....................................................................... 77 ........................................................................................... 79

3.2 ............................................................................................. 803.2.1 ......................................................... 813.2.2 ............................................................................................................ 843.2.3 ........................................................................................................................ 863.2.4 ....................................................................................................................... 873.2.5 ................................................................................................................................ 88

3.3 ........................................................................................................ 903.3.1 ............................................................................................................ 923.3.2 O ..................................................................................................... 923.3.3 O .................................................................................................................... 933.3.4 .................................................................................. 943.3.5 .......................................................................... 95

................................................................................................................................. 97 ........................................................................................................................ 97 ......................................................................................................................................102

KEAAIO 4 TOIKA IKTYA ........................................................................................................................103 ............................................................................................................................................104

4.1 ........................................................................................................................1044.1.1 (Twisted pair) . ..........................................................104

..................................................................................106 ......................................110

4.1.2 O (Coaxial Cable) .............................................................................1114.1.3 (Fiber optics cable) ....................................................................112

5

. ...................................................113 .....................................................................................115 .....................................................................................................115

4.2 ..................................................................................................1174.3 .....................................................................................................122

4.3.1 (LLC - IEEE 802.2) ...............................................................1234.3.2 IEEE 802.3 ...................................................................125

802.3 ...............................................................................127Ethernet ....................................................................................129

4.3.3 802.4 - (Token Bus) ............1304.3.4 802.5 - K (Token Ring) .......1334.3.5 . ..........................................................................................137

.................................................................................................................................139 - .........................................................................................................................140 ......................................................................................................................................142

KEAAIO 5 TA OMIKA TOIXEIA TN IKTYN ...............................................................................................................................143 ............................................................................................................................................144

5.1 MODEM ....................................................................................................................................1445.1.1 modems ...........................................................................1465.1.2 E DTE DCE ..................................................................................1495.1.3 P (Flow Control) . ........................................................................................1515.1.4 (Error Corection), (Data Compression) ..............1535.1.5 E AT .....................................................................................................................154

5.2 K (Network Interface Cards - NiCs) .....................................................................1545.3 E (Repeaters) .........................................................................................................1555.4 (Bridges) ......................................................................................................................158

5.4.1 K .....................................................................................................160 (Transparent Bridges orSpanning Tree Bridges) ...............................................................................................160

O Spanning Tree .................................................................................162 (Source Route Bridges ) .........................................165 M (Translating Bridges) ..............................................................166 E (Encapsulation Bridges) .........................................................167

5.5 M (Switches) .............................................................................................................1685.6 (Routers) ...........................................................................................................1725.7 E ........................................................................................175

5.7.1 O ...................................................................................................175O ..............................................................................................176E ...................................................................................177O ...............................................................................................177X ....................................................178O .........................................................................................179O ..........................................................................................................179T (Rack) .......................................................................................................181

5.7.2 K ..............................................................................................1815.7.3 T .............................................................................1835.7.4 .....................................................................................1855.7.5 - .......................................................1865.7.6 ...........................................................................................187

.................................................................................................................................190 - .........................................................................................................................191 ......................................................................................................................................194

6

KEAAIO 6 TOIKA IKTYA ...............................................................................................................................195 ............................................................................................................................................196

6.1 ..........................................................................................................1966.2 .........................................................................................1976.3 ................................................................................................................1986.4 .25 ...........................................................................................................................................2006.5 ISDN ..........................................................................................................................................2026.6 Frame Relay ...............................................................................................................................2056.7 ATM ...........................................................................................................................................2086.8 xDSL ..........................................................................................................................................2106.9 E ...........................................................................................................213

6.10 WAN ......................................................................................214 .................................................................................................................................216 ........................................................................................................................216 ......................................................................................................................................218

KEAAIO 7 IAIKTYH - INTERNET ...............................................................................................................................219 ............................................................................................................................................220

7.1 .......................................................................................................................2207.1.1 .................................................................................................................220

7.2 TCP/IP .....................................................................................................................2247.2.1 TCP/IP ..................................................................................2247.2.2 OSI TCP/IP .....................................................................................................2267.2.3 TCP/IP .....................230

7.3 TCP ......................................................................................................................2337.3.1 TCP ................................................................................................................237

7.4 UDP .....................................................................................................................2407.5 P .........................................................................................................................2427.6 ....................................................................................................................247

7.6.1 (Media Access Control, MAC ) .......................................................................247

7.6.2 IP ................................................................................................................2497.6.3 ...............................................................................251

7.7 ARP ......................................................................................................................2547.8 O (Domain Name System, DNS) .................................................259

7.8.1 O DNS ...........................................................................................2627.9 ............................................................................................................................264

7.9.1 TCP/IP .....................................................................................2667.9.2 ......................................................................................................2697.9.3 ...................................................................................................2707.9.4 .................................................................................................272

7.10 .....................................................................................................2757.10.1 (Routing Information Protocol, RIP) ...........2777.10.2 E (Exterior Gateway Protocol, EGP) .................................278

7.11 ..........................................................................................................2797.11.1 .................................................................................................................2797.11.2 ...........................................................279

.........................................................................................279 (File Transfer Protocol, FTP) ...............................281 (elecommunications `etwork, Telnet) ............................283 (World Wide Web, WWW ) ..........................................................283

7

.................................................................................................285 TCP/IP (Intranets) .......................................286 ....................................................................................286 ..................................................287 ..................288 ................................................................................................288

.................................................................................................................................289 ........................................................................................................................290 ......................................................................................................................................295

KEAAIO 8 IAXEIPIH KAI AAEIA IKTYOYo o o .......................................................................................................................297 ............................................................................................................................................298

8.1 o ...................................................................................................................2988.1.1 (Configuration Management) ..................................................2998.1.2 o o (Performance Management) .....................................3008.1.3 (Fault Management) .................................................................3028.1.4 o (Accounting Management) .............................................................3028.1.5 (Security Management) ..............................................................303

8.2 ...............................................................................................................3038.2.1 CMIP ..............................................................................................................3048.2.2 SNMP ..........................................................................................305

o o o SNMP ...................................................................307B (Management Information Base, MIB) ...................308 II, RMON, RMON2 .............................................................................310

8.2.3 o ............................................................................................3148.3 ....................................................................................................................314

8.3.1 oo ................................................................................................3148.3.2 Ooo ..................................................................................................3178.3.3 oo ....................................................................................................3188.3.4 .......................................................................................................3208.3.5 oo .................................................................................................3258.3.6 o o ...............................................................................................327

.................................................................................................................................329 - .........................................................................................................................329o ......................................................................................................................................330

KEAAIO 9 O POO TN IKTYN THN KOINNIA TH HPOOPIKHo o ...............................................................................................................................331 ............................................................................................................................................332

9.1 O o oo ........................................................................................3329.1.1 H .......................................3329.1.2 E - .........................................................................3339.1.3 E .......................................................................335

9.2 o o o ......................................................................3369.3 Ooo o ..................................................................................3409.4 o ..........................................................................................................345

.................................................................................................................................348 - .........................................................................................................................349o ......................................................................................................................................349

APAPTHMAO ............................................................................................................................................351

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2-5 () s1(t)=sin(2ft): f () s2(t)=sin(2(3f)t): 3f

() s(t)=sin(2ft)+sin(2(3f)t) s(t) s1(t) s2(t)

, , - s(t), , S(f), - .

, , ,

, . , (bandwidth) -. , , , , , 4 kHz (2-7), - , 100 Hz 10 kHz ( 2-8). , , , , . , 100 Hz 3400 Hz .


Sf

f 2f 3f 5f4f

2-6 s(t)=sin(2ft)+sin(2(3f)t)

Sf

4 KHz

2-7 A

2. 2 -

() . -, , , - , .O , :


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2-8 A

X()

X()

2-9 () ()

, - . , , - , , . ( 2-9). , , , - .

,

. , , , - . O , , - (Amplitude Modulation, AM), - (Frequency Modulation, FM) (Phase Modulation, PM).

, , video, ,

. (Pulse Code Modulation, PCM), , bits.

, modem, ,

, - . O , , - (Amplitude Shift Keying, ASK), (Frequency Shift Keying, FSK) (Phase Shift Keying,PSK). , (, , ).

, O

, 0 1.


T

A ( )

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( )

A

A (

)

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, .2. . ,

, , . , -, , - . , modem ( ) , (.. ) , .

3. . (.. - , ) .

4. . . , modem - , - ( , ).

5. . .


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()

M

Modem H/Y H/YModem

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2.3.2

, , - , ( 2-12).

O - ( ), , , -. , , .

/ . , -, , - . , (), (man-made) . -, , , , .

, - . , -, , .

, , , - ( 2-12):


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K-

K

A-

A-

A-

A

+

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.O , ,

. O , , , , ., , , . - .

/ . ,

r . O 0 1, - , . s bits . O , , . .., - 5 bits, 00000 11111, 32 . r=10 symbols/sec, s=50 bits/sec.

, . O - - , .

/ . -

. , - , , , . O - , bits - . bits , - bits, .


, . , - bits - bits . , bits, , bits, bits .

O bits, - . , . O , , .

( - ), , - - .

, .O

( ), . - , -, - .

, , , .

. -

. , - , . -, - , , - , . , , , , -. , , , (noise). - (Signal to Noise Ratio, SNR), .


2.4 , ,

, ,


( 2-13). , - . ASCII, bits10010010. , - bit 0 bits , 1, . , 100100101. O -, - . , , , -, . , .. .

K-

K-

K

A-

A-

A-

A

A

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10010010

100100101

100100101

+

2-13

( ). , - bit (bit errors), 1 0 0 1. , . O - , -, . - 3 .

- - .

2.4.1

, - , . O , - , (channel capacity).

Nyquist ( )O Nyquist ,

, 2. ( ), ( ) 2 bps.

, -, , . , bits. , , - 4 ( ), 2 bits., , , - :

C = 2Blog2M


modem, - . , =3400 Hz. , , bits , 2=6800 bps.

, , , . , , -, , 2. , .

Shannon ( ) . ,

, . . - , (Signal to Noise Ratio, SNR), . , SNR , , - . O SNR db (decibels) :

, S/N, C , (data) , Shannon-Hartley:

C = Blog2 (1 + S/N) bits/sec

C . , - , C.

(SNR)db =10 log10


1000 , SNR 30 db.

2.5 -

. , , .

2.5.1 bit

O bit (bit rate), bits, -. bits (bits per second, bps), kbps (103 bps) Mbps (106 bps). , (0 1), bit rate R , bit :

2.5.2

O (baud rate), (bauds), , , modem. O baud rate bits (bit rate). , -, bit , baud rate bit rate. , , bit rate baud rate , (baud) bits.

, modem baud 100 baud 2 bits, bit rate 200 bps. , 2 bits 4 , modem 4 - (bauds).

R = 1T


~ 3 kHz S/N = 103, 30.000 bits/sec, Shannon-Hartley :

C = 3.000 log2 (1 + 1000) bits/sec = 30.000 bits/sec

2.5.3

, bits, , , .. bits - (start stop bit). , , - (information rate), bps, , -, bit.


X (msec)10 20 30 40 50 60

0 1 0 1 1 0 0 0 1 1 1 0

P 200 bps

Bits

00

01

10

11

X (msec)

P 100 baud

T/2

T

2-14 P bit .K bit

10 bits, 3 bits , bit 300 bps. 70%. , 300 bps 0,7 =210 bps.


. , , . , .

, -. , - .

, , . , , , , , , , , .

Nyquist Shannon - - .

- , bit (bit rate), (baud rate) (information rate) .

ANAKEAAIH

1. :. .. .. .

2. ;

3. , :. 5 kHz.. 5 kHz 10 kHz.. 19 kHz 23 53 kHz.

4. .

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1. ., ., , 1997.2. Roden M., Analog and Digital Communication Systems, 4th ed., Prentice Hall, 1996.3. Stallings W., Data & Computer Communications, 6th ed., Prentice Hall, 2000.4. Walrand J., , . , 1997.


5. , - :. .. .. ISDN.. CD.. CD.

. .

6. .

7. O - , , ,

8. , - :. .. .. .

9. O , - :. .. .. .

10. - =4kHz. . 4

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. ;

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.


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.

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. , , , . .

O , , - , - .

. - , - . - , - . - .

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3.1.1

, - .

, . ,


O , , - , , . - , , -, , , ..

ITOPIKO HMEIMA

, . , , . ( ), , -, . O . , , , . , , -, .

O -

, - , -. , , - . , . - , , .

, , , - . ` ,, , . - , - , .

O . O

, 3-2.

K E A A I O 3 M E A M E T A O H 73

X M

3-1

, - - . - , , , . , - . (bandwidth, BW), - . , .

O . -

MHz, . - . , 9.9 Gbps - , , Britannica .

- , -. O - ( )


()

/

3-2 O

. O : (), .

, , - . , - .

, , , , , , - , - . , , 30.000 , - . BSFOCS, , O- , SEA ME WE 3 (South East Asia MiddleEast West Europe), (, . ), (, , ) - (, ) , ADRIA1, (), (Durres) (Dubrovnik).

O , , -, , , , -, , , , , .


3-3 O

3.1.2

O -, , , , , - .

, -, , / , - . , , , - , ,, . , , , , - .

, . - , , , - , - , . , . , , - ( , - ).

- .


K

O E

3-4

O

(GHz). , 2 40 GHz, - 2 18 GHz. , Mbps ( 2 GHz) - Mbps ( 20 GHz).

O - . - , -. 40-50 .

O , , , , - - .

O -

(), . O -, (uplink) (downlink). O - -, , , ( 3-5). H (broadcast) (broadcasting services), .


E

35.880 km

A Z K Z

3-5

O 1958, , Early Bird, 6 1965. O , , -, 10 . - , - . , - , .

-, 35.880 Km - (11.040 /). , - , . , , . O , , - , 3-6. - 120, , 3-7. O , , 4 6 GHz, 12-14 GHz 19-29 GHz.


A B

E A B

A B

A B

3-6

,

- . , . , , -, , , , . O , , 30 900 MHz. , ( -). , , - .

1946. , - . . , , - .

-. ,


3-7

(), - (1,5-13). . O - 900 1800 MHz . -, . O - , . - ( 900 1800 MHz) - . - , , . , - , - , .

, - , -. , , - . . , - - . , , , . , ( -, Kbps) .

3.2

- .

O , , , , - , -. , , -, .

O , , , , , , . O -, ,


, , - , - , . . , , - , , - , . - , . - , .

3.2.1

- (, ) , .

, , . - . (R) -, , , , .

, (RL) (Rc) . (RL) -, , - . , . , - , - , - .


, , :

E

(Rc) , . , , , , - . , - . , , , . - , .

O , (Z), :

Z2 = R2 + (RL RC)2

, , . , , , - , . , , , - .

, , . - 3-8, . () 3 Volt (Ri) (R) 300 , :

UR = ER/(R+Ri) = 3 300/600 = 1,5 V

P = UR 2/R = 7,5 mW.

, , R 150 , :


, . , - . , , , . , - .

UR = ER/(R + Ri) = 3 150/450 = 1 V

P = UR 2/R = 6,6 mW

600 , :

UR = ER/(R + Ri) = 3 600/900 = 2 V

P = UR 2/R = 6,6 mW

, , , - .

, , , . , , , . , - , - . , -, , . , . , , - (). -, .


Ri

M

RE

3-8

3.2.2

. - , , bits (bit errors), .

, , . -, . 3-9 - ( dB ) . , -, . (amplitude distortion). , , . , , , .


0

A (dB)

(KHz)

3

6

9

12

0 0,5 1

K

1,5 2 2,5 3 3,5 415

3-9

, , , , . - , - .

E

. . , - , , -, , ( ). (groupdelay).

3-10 - . ,, 1800 Hz. - sec 1800 Hz.

2 , - -. , , - ( 3-11).


4000

(sec)

(KHz)

3000

2000

1000

0

0 0,5 1 1,5 2 2,5 3 3,5 4

3-10

3.2.3

, .

O : , -

, , , . , -

, .. . , -

. , -

: , . -

-. , - .

, , .

, -, ().

, , . - ( ).

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. dBm,

. , - . -


H(f)

MT

x(t) y(t)

3-11

dB. - , 20 dB - , 30 dB .

3.2.4

. - , , - . , -, , , , . - .

, . , - . , ,, , .

, - . -, - x y ( 3-12). x y . - x , - y . x y.


A x

M

y

B

T KT

3-12

. , , , - .

- , . -, 50 -, 49 . 3-13 , - , . , , 1 3 , , - 30 3 Mbps.

3.2.5

. , - , .

3-14, - -. O , . - . ,


M X

(Mbps)

A (Km)

100

10

0 1 2 3 4 5 61

3-13 ,

, . .

, - . , - . , , . , , , - ( 3-15).


T T

K

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3-14 H

H

T K T

T K

H

3-15

3.3 O -

. . , , , . , , - . , , - .

, , :

: - , . . , , () , , , .

: , , - . , (). , , .

: , ( ), - .


: -, , .

: - . , -

, , - . , - . , . , , - , . .

, , , . O , , . , -, , , . , , , TeraHertz (1012 Hertz). , - bit .

, -, -, ( ) . , - .

, -, .


3.3.1

KHz -, . -, . , , - . H , . -, . , , - .

- , -. , .

3.3.2 O

, - -. , , , . , , -, , , . , , . , , . , - , .


1. 2. M K3.

: 1. E 2. M

3.3.3 O

O - , , .

O , - ( Gbps). - 2 10 Gbps, 20, 40 50 Gbps. , Tbps. , , . - , -, - , - . - , - . , . , , 1000 500 4000 , , , 45 . , , - . , - ( , .).

, , , - , - . , - , ,


1. , 2. , 3. ,

: 1. 2. 3.

, . , -, , , - . , , , .

3.3.4

O - . , . , , - .

O , 6 Gbps, 1,5 45 Mbps. , , , . . - , - , , , . , -


1. Gbps2. (Wave division

Multiplexing) Tbps.3. 4. 5. 6. 7.

: 1. , -

2. 3.

, , .

3.3.5

O - , , . , , , (broadcasting).

. 3-1 -, 3-2 .


1. 2. 3.

: 1. 2. 3. 4. ,

1. 2. 45 Mbps,

.3. , -

4. , -

:

1. 2. 3. -

.4.


3-1

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3. ;

4. , - ;

5. ;

6. , ;

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10. ;

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13. ;

14. , - ;

15. : O O

16. - ; . . .

17. ;. ` . O . .

18. ;. . . O .

19. ; . . . ,

20. - ;. O . O .

21. ;. . . .


22. - ;. 2-40 KHz. 2-40 MHz. 2-40 GHz. 2-40 THz

23. ;. . . .

24. , ;. ` . ` . `

25. ; . . .

26. ; a. b. c.

27. ; . . .

28. , ;. . .

29. :. . .


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33. :

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35. : .


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1. A A. ., Y,

4 , 19972. ., , 19943. ., O : , 19894. ., , ,

19845. ., , 19886. Maurice Gagnaire, An Overview of Broad-Band Access Technologies, Proceedings

of the IEEE, Vol.85, No. 12, Dec. 19977. Tanenbaum A., , , 19928. The International Engineering Consortium, Fiber - Optic Technology Tutorial,

http://www.iec.org



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, . ` . ` . ` , -

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.

, - .

-, , - , .

4.1 , ,

: . O . .

4.1.1 (Twisted pair).

. . O - . , .

-


4-1

UTP (Unshilded Twisted Pair). . -

. - .

FTP ( Foiled Twisted Pair). -

.

. . - , (drain wire).

STP (Shilded Twisted Pair). -

.

. -

K E A A I O 4 T O I K A I K T Y A 105

E 4-1 K UTP

E 4-2 K FTP

. - (drain wire) - .

(S/FTP,S/STP). , -

. S/FTP (Shilded/Foiled Twisted Pair), SSTP (Screened/ShildedTwisted Pair), .

X

, , (solidwire) , (stranded wire), -, (twist pitch), - (insulation type) - (sheath material).


E 4-3 K STP

E 4-4 () K S/FTP () K S/STP

()

()

O - , /TIA 568- , ( / , ElectronicIndustry Association / Telecommunications Industry Association), - . -, .

- .

, - . , .

, . - , , . - I M ( Balanced Transmission Line).-, . , , - .

, , - .


+1V+N+N +N +2V

1V+N

E O

4-2 .

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, -

(attenuation). , , -: (), ,

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, , . .

(skin effect), , - . - , , . - . , , -

, -. EIA/ TIA 568-, , , 100 .

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- , . , - . , , - , - .

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. .

dB. O dB, .

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O (NEXT) NEXT , , .

, ACR, - .


FEXT

E

4-4 (FEXT)

NEXT

E

4-3 (NEXT)

K

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O . -.

5e, - , - (UTP), - 5 ( - ) .

, - 5e.


(dB/305 m) NEXT (dB/305m)Cat 3 Cat 4 Cat 5 Cat 3 Cat 4 Cat 5

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(dB/100 m) NEXT (dB/100m) ACR (dB/100m)1 MHz 2 65,3 63,310 MHz 6,5 50,3 43,820 MHz 9,3 45,8 36,562,5 MHz 17 38,4 21,4100 MHz 22 35,3 13,3160 MHz 28,6 32,3 3,7

4-2 X 5e

4-1 X

UTP 5 5e - - 1Gbps/sec.

, , 6, 7, 8. , , 250 MHz,600 MHz, 900MHz. O S/STP.

O , . .

4.1.2 O (Coaxial Cable)

, - . , - , - .

. - , , . - . , (drain wire). , , - .

: Thicknet () Thinnet ().

.


E

K

4-5 O

, . , - .

, , . , 10Mbps 500 Thicknet 185 Thinnet .

- , Thicknet Thinnet, . - .

4.1.3 (Fiber optics cable)

. , , - . , 5Km 10 Gbps.

4-6.

, - . - , clading buffer. , , (cladding) (- 4-6). .


O

E

E

4-6 H

, , , . - - .

T .

LED (LightEmmiting Diode) LASER (Light Amplification by Stimulated Emission offRadiation), , , 800nm 1.500nm.

O , , . . ( Multimode fiber optics)

O - () - (cladding). O 10-6 . O 50m/ 125m, 62,5/125, 85/125 100/140. O , , 62,5/ 125. 900m. - , 4-7, 4-8. (multimode), - , -. O : (step index) (graded index).

O (step index).

. , 4-7.


, . , . O, , , - ,graded index, -, .

O (graded index)O

. - . , 4-8.

(single mode fiber optics). -. , , . 4-9.


4-8 O (graded index)

4-9 (single mode fiber optic)

4-7 O (step index)

5m 10m 8,3 m.

X .

O - , , , , . 1310 nm 1550 nm. 850 nm 1300 nm. , , - .

O - . O - , - 3Km, 10 Km.

, , , . , - , . , . , , . , - LED, - LASER. T 62,5/125 3,5 dB/Km 850 nm 1.0dB/Km 1300nm. - 0,5 dB/Km 1310 nm 0,4 dB/Km 1550nm.

T .

1 36 . - full-duplex .

. ,

. , -. -, . , , . - Tight Buffer. 4-10() .


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E

E (Buffer)

O

E

4-10 () ( Tight Buffer)

E

E (Buffer)

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4-10 () O Patch cord

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4.2

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.


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E

E

E E

E E

K M E

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E

E

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()

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. . (Broadcast) (Multicast).

, . , , .

, , ( ).

O , , - .

.O :

, ( 4-12).

(Bus Topology)O - . - (taps). , , . O , , , , . , , . , , - , , - . , - , - , ., .

(Ring Topology) - . -


, - , . ,, .

E

"" - , . . -, , .

(Star Topology)O . - -, , . H , . , , -, , , . , - , , , , - .O :

I. O -. O -.

II. O .

III. O .


-. - . , , - .

E


E

E

A

E

E

E

E

E E

E E

K M E

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K M E

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K M E()

()

4-13 () ()

, . O -: -.

E

. -. , . , , , , .

. .

4.3

. , , , . ,, , - . (Institute of Electrical and Electronic Engineers, IE-EE) (EuropeanComputer Manufacturing Association, ECMA) - OSI.

, - OSI. . . .

O , 802, (LAN) (MAN) . -, ( MAN , ). 6 - -. , . 802. - .

802, OSI - : - (Logical Link Control, LLC) (Medium Access Control, MAC).


802.2. 802.3,4 5 .

4.3.1 (LLC - IEEE 802.2)

802.2 LLC. , LLC -, 802.3,4 5. O LLC . - " " (SAPs - Service AccessPoints), LLC. LLC - .

LLC : (Unacknoledged con-

nectionless service). - . , -, . , , , . - -


E

E

(LLC)

M (MAC)

E

OSI IEEE 802

M M

4-14 OSI IEEE 8

, .

(Acknoledged conne-ctionless service). , , - - . -, - (point to point).

(Connection oriented service). LLC. , -. -. . O . : -, . - , -


E

E

E

A ()

E

B

A

E

A

E X

Y(E)

Y(E

)

XY(E)

E

A ()

E

B

A

E

A

4-15 A

. . - .

. O LLC - : (request), (indication), (response) (confirm). 4-15.

LLC -. , . O .

: - bit. - . bit HDLC ( Y , High Level Data Link Control, ). HDLC 802.2.

4.3.2 802.3

802.3 , .

802.3 MAC. 802.3 - MAC LLC . MAC . O , - 802.3, " - " (Carrier SenseMultiple Access with Collision Detection - CSMA/CD). - . -, .

CSMA/CD. CSMA/CDO CSMA/CD -


ethernet. To Ethernet Xerox 1970 802.3. Ethernet ( I II). Ethernet ( ) 802.3, 802.3. , Ethernet , CSMA/CD Ethernet 802.3.O : , , (). , , . , . , , , , - (collision). , , - , , , . , - . , , , . , , CSMA/CD, . , -, -, , -, , , , , ( - ) . , , . - , . - , t0. -, , , to, - . , t0+-. , . O , , 2-,


, . , , , 2 . , , -, . CSMA/CD , - 1518 (bytes), 64 . , - , . - , 0 Volt, , -. , - Manchester. Manchester, -: bit 0 -, bit 1 , () 0 Volts. +0,85 Volts, -0,85 Volts.

, , - , , . , , -. , .

B IEEE 802.3.

- , 802.3 - . - 802.3.


Manchester0

0

+

0

tB

1 0 1 1 0 1

4-16 Manchester

:XBase/BroadbandY

: MbpsBase / Broadband , (segment) 802.3

.

Ethernet II 10base5. 802.3 -

, , (Fiber Ethernet). : 10Base-F. 10Base -F: Fiber Ethernet

10Base-F FOIRL (Fiber Optic Inter-Repeater Link), . - 62.5/125 m LEDs. - 10Base-FL (HUBs) 2m. , ( 2Km),


10Base5 O 10 Mbps 500 m

50 Ohm thick 10Base2 O 10 Mbps 185 m

50 Ohm thin (RG-58)

1Base5 1 Mbps 250 m

(UTP)10BaseT 10 Mbps 100 m

(UTP)

10Broad36 O 10 Mbps 3600 m 75 Ohm

( ). ,, , - (.. - ).

Ethernet .

802.3. , , 802.3 . , : 802.3u (Fast Ethernet) 802.3z (Gigabit Ethernet) Fast Ethernet

Fast Ethernet 100Mbps. , Fast Ethernet, . , - : 100Base-TX, 100Base-FX 100Base-T4. 100Base-TX: UTP (-

) 5, STP (). 100 . - , -. , , -, . , -, .

100Base-T4: UTP 3 . - , - . - , . 100 . , () . 100-BaseT4, 100BaseTX, - .

100Base-FX: (62.5/125m) . - 412 half-dublex 2 - full-dublex. - 25 .

Gigabit Ethernet gigabit Ethernet IEEE 802.3z 802.3. -


1000 Mbps. 5 (cat5 enhance). 1000BaseT cat 5e.To gigabit Ethernet . 62.5 m 1000BaseSX 275 , 50 m 550 . 1000BaseLX 62.5 50 microns 550 9 m 5km.

- gigabit switches .

4.3.3 802.4 - (Token Bus)

802.3, , , General Motors, . O - 802.3. - . (). - - .

802.4, (token bus). , token bus, MAP (Manufacturing Automation Protocol, AK), General Motors. - , 802.4 , - .

75 Ohm - (RG6, RG11, RG59, JT4750J 0.5 1 -


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