1. Local Aria Network.
, .
j, . , . .
2. Wide Aria Network.
, . . . -㳺 ( ). 䒺 (subscriber line). . , , - ( ).
MAN (Metropolean Aria Network).
ᒺ LAN ( ). . LAN. MAN .
GAN (Global Aria Network).
.
2. INTERNET TCP
INTERNET TCP (Transmission Control Protocol) . ³ 璺.
TCP . , TCP, 璺 , TCP . , , TCP. , .
TCP , ( PSH 1). TCP, , . , out of band.
, 璺, , 璺 , . , IP- , IP-. , , IP-.
. , , IP-. (MTU) , . MTU .
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TCP . : , (, 21 FTP, 23 telnet), . ǒ TCP , .
ǒ TCP . IP- . 璺 :
- 璺 . TCP (active open)/
- ϳ TCP - , 璺.
- TCP (passive open) , .
- , , (active port) .
- - . ǒ . 璺.
TCP . , , , , , TCP.
, . , , , . (), , . TCP, , , . , . , , .
TCP . : (Source Port) 2 , -
- (Destination Port) 2 , -
- (Sequence Number) 4 , ,
- ϳ (Acknowlegement Number) 4 , , , .
- (Hlen) 4 , TCP, 32- . , .
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- (Reserved) 6 , .
- (Code Bits) 6 , , .
- URG
- ACK
- PSH
- RST 璺
- SYN , 璺
- FIN , , ,
- ³ (Window) 2 , , ,
- (Checksum) 2 ,
- (Urgent pointer) 2 , URG, , ,
- (Options) , 3 , , , .
- (Padding) , , 32- .
TCP 璺.
3. ˲ ʲ ò
- - , Pn, , , . log2 (1+ Pc/Pn) .
㳿 56 , .
F
Գ - ; (0,5- 20 ); (U = 2,48 /c).
( ). ֳ . ֳ .
㳿 XDSL
xDSL digital Sybscriber Line .
ǒ XDSL 㳿.
- ADSL - asymetric digital Sybscriber Line (37% XDSL)
. 10-10, ( 10-5 10-6; 10-3). ADSL .
1) 0-3,4
2) 3,4-30 ,
3) 30-138 . U=15-9Mbit/c.
-
256 4KHz
,
, ( ).
HDSL High bit-rate DSL 璺, 2 3 1,544 \ 2,048 \. .
- 2 \
-
- ,
- 2 3
- ³ 4,2 , .
SDSL Single line DSL , HDSL, 1- .
- 3 ( , )
- .
R-ADSL Rate-Adaptive DSL ,
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ADSL.
- , ADSL, .
V-DSL Very high bit-rate 㳺, 璺
52 \ 2,3 / 13-26 \
ADSL DSL - 1,5-8 \
640 \ 1,5 \.
, VADSL (Gilibe DSL) universal DSL, , Gilibe. U=1,5 \ ( ), U=384 \ ( ). IDSL (ISDN DSL)- Intergrative Srvice Digital Network DSL.
, , xDSL . 㳿 , .
4. Internet IP. '
Internet IP
TCP/IP 䳿 Internet Protocol (IP). :
- ;
- .
IP 㳺, . IP , , , .
IP . :
- (VERS) IP.
- (HLEN) IP 4 , 32- . 20 ( 32- ), ᒺ (IP OPTIONS).
- (SERVICE TYPE) 1 . (PRECEDENCE). 0 ( ) 7 ( ). . , . D (delay) , , T - , R - .
- (TOTAL LENGTH) 2 .
- (IDENTIFICATION) 2 , . .
- (FLAGS) 3 , ( Do not Fragment - DF - ), , ( More Fragments - MF - , ).
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- (FRAGMENT OFFSET) 13 , , . / .
- (TIME TO LIVE) 1 , . IP. ; ( ). .
- (PROTOCOL) 1 , (, TCP, UDP RIP).
- (HEADER CHECKSUM) 2 , .
- (SOURCE IP ADDRESS) (DESTINATION IP ADDRESS) - 32 , .
- (IP OPTIONS) . , . , , , . , 32- .
(Data) , , 65535 , , IP-. Ethernet, 1500 , Ethernet.
IP:
Vedsion | HLEN | Service Type | Total Length | ||||
Identification | D F | M F | D | Fragment offset | |||
Time ti live | Protocol | Header Checksum | |||||
SOURCE IP ADDRESS | |||||||
DESTINATION IP ADDRESS) | |||||||
IP OPTIONS | |||||||
Data | |||||||
A | 01.0.0 | 126.0.0.0 |
B | 128.0.0.0 | 191.255.0.0 |
C | 192.0.1.0. | 223.255.255.0 |
D | 224.0.0.0 | 239.255.255.255 |
E | 240.0.0.0 | 247.255.255.255 |
,