(Dial-in). - . . .
- T - , . . 1 (1,5 /) 3 (45 /), .
ISDN
. ISDN . , . (Basic Rate Interface, BRI) , B-, . , D- ( -), 16 /. , -, . ISDN .
. ISDN-, (Primary Rate Interface, PRI). PRI BRI. PRI "", 23 - D- (64 /) 1,544 /. 1. PRI , .
Frame Relay
Frame Relay. , , , AT&T. 1.10 , Frame Relay .
. 1.10. Frame Relay
. , () . - , , .
X.25
.25 , . X.25 . .25 ( ) 64 /. .25 .
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X.25, :
DTE (data terminal equipment) ( , , , , .. ).
DCE (data circuit-terminating equipment) ( , ).
PSE (packet switching exchange) .
.25 :
1) ;
2) ;
3) .
.25 OSI: , . .
DSL
, DSL :
- ADSL - Asymmetric Digital Subscriber Line. .
- SDSL - Simple Digital Subscriber Line. , .
- VDSL - Very High Speed Digital Subscriber Line. .
ISDN, DSL , . DSL " ".
ISDN, DSL , . . , , , .
DSL- , ISDN. DSL- : . DSL Lite (. .). DSL ISDN, DSL- , ISDN, , . , DSL "" . DSL- .
DSL- ,
30
DNS (Domain Name System- )- . IP- ( ), . ( OSI- , : TCP/IP, (): ).
- , . , ru.wikipedia.org: -org, - Wikipedia, - ru
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- , wikipedia.org .org
DNS- - , DNS, , .
DNS- ( ) DNS.
:
.aero , ;
.arpa , IP- ;
.arts ;
.biz ,
.com
.gov ()
.net
.shop -
.tv -
:
: