/ . , , .
, . , , , , , .
, . :
, . . :
LAN (Local Area Network) ( );
MAN/CAN (Metropolitan/Campus Area Network) ( );
WAN (Wide Area Network) ( ).
Internet, .
(, , , , (), ), .
(, , ), .
. , Ethernet .
, , , .
(, ),
( )
( ).
. , TCP/IP, IPX/SPX, 25 . , , .
, . . , , . , MS Windows, Novell NetWare, UNIX/Linux .
( ),
( , , . . ).
(, , .), (, , .), / (WWW, E-mail, .).
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. OSI
. , , , . , , , . , .
:
ITU-T (International Telecommunications Union sector Telecommunication) , . 1993 CCITT (Consultative Committee for International Telephone and telegraphy), ( ). (Telecommunication), R ( ) D ().
ISO (International Organization for Standardization) . 89 (ANSI , DIN , BSI .).
IEEE (Institute of Electrical and Electronics Engineers) .
OSI (Open System Interconnection) 1983 . ISO ITU-T. ( ) .
1.2.1.
. 1.2.1. OSI.
: AH (application header) , PH (presentation) , SH (session) , TH (transport) , NH (network) , DH (data link) , DT (data link tail) .
, , , , /.
- () . 1.2.2, M (message), H (header) T (tail).
. 1.2.2. .
, 1.2.3, PDU (protocol data unit) .
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:
, .
.
.
(service) , .
( ), , Ethernet .
, , IP ATM.
:
(Physical) , .
(Data Link) (, / ).
(Network) (, , ).
(Transport) .
(Session) , / , .
(Presentation) (, SSL (Secure Socket Layer)).
(Application) . , FTP (File Transfer Protocol), Telnet .
, . . , . .
(polling)
(primary) (S secondary) . (, . .).
(token passing) . 1 3, () .
. 1.3.2.
Token Ring/Token Bus (IEEE 802.5/802.4) FDDI.
Token Ring 1984 . IBM 4 / ( 16 /). 1998 . High-Speed Token Ring 100 155 /. 70 ( 4000 ), STP (Shielded Twisted Pair) 100 , UTP (Unshielded Twisted Pair) 45 , - . 260 .
FDDI (Fiber Distributed Data Interface ) ANSI 1986-8 . 500 ( ) 100 100 /.
(competition) .
CSMA/CD (Carrier Sensing Multiple Access with Collision Detection) , , ().
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. (, Ethernet ). ( Ethernet 16).
, .
(collision domain), . . , , .
ISDN
ISDN (Integrated Services Digital Network) , ( , , , . .) . ISDN 70- . ITU-T (CCITT) .
ISDN 64 / N-ISDN (Narrowband). - ( 64 / ) , , . ISDN , , ATM, xDSL, Frame Relay .