, , 1 . , . , , , , .
3 , : , .
: , , , . , ( ). . . , .
: ( ). , , .
: . -, , , . , , .
| web- | ( /) | ||
| : / - 1/ : 10/-5/ | , | ||
| , | |||
| 1-10/ | , | ||
TCP: .
. - . TCP-, ( ). .
. , , . .
.
UDP: , . - . . .
|
|
|
| SMTP | TCP | |
| Telnet | TCP | |
| Web | HTTP | TCP |
| FTP | TCP | |
| NFS | UDP TCP | |
| , Real Networks | UDP TCP | |
| - | , Dialpad | , UDP |
.
HTTP
web HTTP, . : , , HTTP-. . web-, . web-, HTTP- , web-. , . TCP . . HTTP .
(1.0 ). TCP 1 , - .
(RTT) - , . , . : HTML-.
: , ( ).
HTTP-: 2 : .
:
| Sp | URL | sp | cr | lf | |||
| Sp | cr | lf | |||||
| Sp | cr | lf | |||||
| cr | Lf | ||||||
- , - . 3 : , URL HTTP. GET, HEAD, POST ( ()).
: User-Agent - ( ), Accept-Language - .
:
| sp | URL | sp | cr | lf | |||
| sp | cr | lf | |||||
| sp | cr | lf | |||||
| cr | lf | ||||||
3 : , . . 3 : , , . : The Date - , Server - , Last-modified - , Content-Length - , Content-type - .
|
|
|
: 200 - , 400 Bad Request ( ), 404 Not Found ( ), 505 HTTP Version Not Supported ( ).
HTTP, cookies, GET HTTP.
HTTP- . , .. , , . HTTP 2 : cookie.
: - . . ( , 401 - Autorization Required, WWW-Authenticate: , . , , Authorization: . ( ). .
Cookie: cookie . : 1) cookie- ; 2) cookie- ; 3) cookie-, ; 4) , web-.
, ID Set-cookie:, cookie-, cookie:. : , . . .
GET : Web-, .. web- . -.
: . GET - , HTTP . : If-Modified-Since: - Last-Modified, . , 304 - Not Modified , , .
FTP.
FTP- , - . . , .
: User Interfase User
Server
PI 
Client PI
- (control connection)
Server Client
DTP DTP
DTP - data transfer process
PI - protocol Interpreter
HTTP FTP , TCP. FTP 2 TCP : ( : , , ) ( ). .. , .
|
|
|
FTP () 21 ( , ). , TCP- , , . 1 , . FTP- . . , , . FTP-, . 4 , : USER username:, PASS password:, LIST: ( , , ), RETR filename: ( , ), STOR filename: ( ). , .
SMTP.
. -, .
SMTPserver SMTP SMTP-server
SMTP UA
User POP3
agent IMAP IMAP
POP3 mailbox mailbox
web
SMTP . TCP . SMTP 7- . SMTP . , , .
1) SMTP- TCP- 25 , , . 2) - ( ). 3) .
, .
: - , (From: To: - , Subject: - , , .
- , < 32, CR LF.
MIME - . MIME: Content-Type: ( ), Content-Transfer-Encoding: ( ). 7 . : text, image, application.
multipart - .
