802 IEEE 1980 . ( IEEE 802.x) ISO 8802‑1 ISO 8802‑5. 802 , , , . IEEE 802.x . 802.x :
- (Logical Link Control, LLC)
- (Media Access Control).
LLC , . , , LLC.
MAC , . Ethernet, Token Ring, FDDI, Fast Ethernet, 100VG-AnyLAN . MAC.
802 , , .
802.1 , IEEE 802 OSI, .
:
- 802.1d /; .
- 802.1h ( ).
- 802.1p .
- 802.1q (Virtual LAN, VLAN) /.
802.2 LLC.
802.3 MAC CSMA/CD. 802.3 Ethernet (10 /c), 802.3u Fast Ethernet (100 /c), 802.3z 802.3ab Gigabit Ethernet (1 /). 802.3x . 802.4 MAC (Token Ring, MAP (Manufacturing Automation Protocol) ).
802.5 MAC (Token Ring).
802.6 (Metropolitan Area Network, MAN).
802.7 .
802.8 - .
802.9 ISDN .
802.10 .
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802.11 .
802.12 (100VG-AnyLAN).
32 CSMA/CD
CSMA/CD , -, , , - .
. , , . , , ( ), (9.6 ), , , .
, , , , , . .
, . (collision). ( ). , (jam), 32 , ( ). (, ).
( 512 , .. 51,2 ). , 0..2n (1<=n<=10) 0..210 (10<n<=16). n . 16 ( ), MAC .
( , .) . , , . , , (, ) . , . Tmin , RTT (round trip time, , ), : Tmin ≥ RTT. Ethernet ,
31 Ethernet. 10/.
Ethernet 10 /:
- 10BaseT ( );
- 10Base2 ( );
- 10Base5 ( );
- 10BaseFL ().
s
1990 IEEE 802.3 Ethernet . l0BaseT (10 10 /, Base , ) Ethernet, (UTP). (STP) lOBaseT - .
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, , Ethernet. lOBaseT (multiport) . , , : , .
l0BaseT 100 (328 ). 2,5 ( 8 ). l0BaseT 1024 .
3,4 5 UTP | |
RJ-45 | |
100 IEEE 802.3, , | |
( :)) | |
, | - 1024 |
Base2
IEEE 802.3 10Base2 [10 - 10 /, Base , 2 , 100 ( 185 )].
, Ethernet, 185 . 0,5 (20 ). , , 185- , 30 .
Ethernet:
- BNC -;
- BNC -;
- BNC-.
Ethernet . IEEE Ethernet -- . - .
BNC -, , . , 30 , 20 5 . - , . - , .
Ethernet . :
- ;
- ;
- .
IEEE 802.3, Ethernet 30 ( ) .
185 (607 ) | |
BNC T- | |
5 4- | |
- 30 | |
, | ( ) |
925 (3035 ) | |
, | - 1024 |
.
Base5
IEEE 10Base5 [10 10 /, Base , 5 500 (5 100 )]. - Ethernet.
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( Ethernet) . Ethernet 100 ( , ..) . , , , . Ethernet 500 2500 (8200 ).
Ethernet , Ethernet.
:
- .
, , ( ), . - .
( ) . - DIX-, AUI-. .
- N- ( -) -.
Ethernet , Ethernet.
500 (1650 ) | |
BNC T- | |
5 4- | |
, | ( ) |
2500 (8200 ) | |
- 100 |
Ethernet. , .
.
BaseFL
10BaseFL (10 - 10 /, Base - , FL - ) Ethernet, .
10BaseFL - ( ). 10BaseFL - 2000.
Fast Ethernet
10- Ethernet 15 . 90- .
1992 , Ethernet, SynOptics, 3Com , Fast Ethernet Alliance , Ethernet.
IEEE 802.3 Fast Ethernet 802.3u, , 802.3 21 30.
Fast Ethernet Ethernet (. 4.4). MAC LLC Fast Ethernet , 802.3 802.2.
Fast Ethernet , :
- , ;
5, ;
3, .
Fast Ethernet , . Fast Ethernet 200 , 10 10 10- Ethernet.
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Fast Ethernet. , 90- , . Fast Ethernet , , , ( - - ).
. 4.4 Fast Ethernet
Ethernet ( ), Fast Ethernet - , .
802.3 Fast Ethernet :
- 100Base-TX UTP 5 STP Type 1;
- 100Base-T4 UTP 3, 4 5;
- 100Base-FX , .
.
- Fast Ethernet 10- Ethernet.
- (IPG) 0,96 , 10 . , , , , MAC, .
- Idle ( , Ethernet 10 /).
:
- (reconciliation sublayer);
- (Media Independent Interface, MII);
- (Physical layer device, PHY).
, MAC, AUI, II.
(PHY) , , (. . 4.4):
- , MAC 4/5 8/6 ( Fast Ethernet);
- (PMD), , NRZI MLT-3;
- , , , ( ).
II MAC PHY.