L (Length) .
(Frame Check Sequence, FCS). , . ().
(Data) 9.10 , 46 , -, 46 .
Raw 802.3/Nowell 802.3 Nowell 802.2.
Ethernet DIX (II) , Raw 802.3 , L T (Type), , , IP 204810.
Ethernet SNAP (SubNetwork Access Protocol) , 802.3/LLC SNAP,
: OUI (Organizationally Unique Identifier) Type. OUI , , Type. Type Ethernet DIX (II). 8.1 .
8.1.
Ethernet II | IPX, IP, Apple Talk Phase I |
Ethernet 802.3 | IPX |
Ethernet 802.2 | IPX, FTAM |
Ethernet SNAP | IPX, IP, Apple Talk Phase II |
8.4.2 Token Ring ( 802.5)
, 8.11 Token Ring. ,
() . . , (token). 8.11 5 , 2. , 5 , . , 5 , 4, 1 , , 2. , (. , 8.12) 1, 3. 3, 6, 5 ( ). 5 1 , . 5 , 4. 5 2. . - . , .
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MAC-. , . , 3 . 7 , . Token Ring 4 / 16 /. -.
Token Ring :
- ;
- ;
- .
.
(Start Delimiter, SD) - JK0JK000 .
(Access Control, AC), - , 8.12. PPP , 0 7, 7 . T, 1, 0 , ( ). 1 () , , . , , , . , , . RRR .
(End Delimiter, ED). JK1JK1IE . I=0 , , I=1 . E=0 , , E=1. 8.12 Token Ring.
.
.
(Frame Control, FC) - MAC LLC. MAC , . LLC
. Token Ring 6 () :
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- Duplicate Address Test, DAT - , - , ;
- Active Monitor Present, AMP 3 ;
- Standby Monitor Present, SMP , ;
- Claim Token, CT - , ;
- Beacon, BCN , , , , , ;
- Purge, PRG .
, , (Destination Address, DA) (Source Address, SA).
, 802.3 (. ).
(INFO) MAC , , , LLC . , , .
(FCS) 802.3.
(ED) .
(FS) 1 ( ) , ACxxACxx. A, (1) , . , , , , , , . C . 1, 1 , E, , , , .
, , .
Token Ring , - . 260 100 , 72 45 .
Token Ring 4000 . . 260 10, 2,6, (3) - . - , .
, IBM Token Ring, High-Speed Token Ring, HSTR, 100 155 /.
8.4.3 FDDI
- . FDDI (Fiber Distributed Data Interface) . , , FDDI. , , , -
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, , Token Ring, FDDI. , .
- , , . . 100 /.
FDDI , . , - (- ) , . Warp, . .
FDDI , , . , Token Ring, , , . FDDI () ( ) . . , . .
Token Ring .
FDDI Station Management (SMT).
FDDI. 8.14 OSI FDDI.
, SMT.
FDDI . . , , . 8.15 FDDI . SMT -
, . FDDI , , - , . , .
FDDI 4/5 ( ) - NRZI. 125 . - , 50 62,5 , 125 . 850 (0,85 ), 1300 (1,3 ) 1500 (1,5 ). 850 1300 , 1300 1500 .
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FDDI . , . , . .
8.4.4 Ethernet Fast Ethernet 100VG-AnyLAN
90- 10- Ethernet . , , , , , 100 /. , - Fast Ethernet 100VG-AnyLAN, Ethernet. SynOp-
tics 3Com, Hewlett-Packard AT&T.
90- 10- Ethernet . , , , , , 100 /. , - Fast Ethernet 100VG-AnyLAN, Ethernet. SynOptics 3Com, Hewlett-Packard AT&T. . Fast Ethernet CSMA/CD Ethernet, HP AT&T , Demand Priority, Ethernet. 1995 . Fast Ethernet 802.3u Ethernet 802.3, 100VG-AnyLAN, 802.12.
. Fast Ethernet :
- - ( ) 100Base-FX;
- 5 ( ) 100Bas-TX;
- 3 ( ) 100Bas-T4.
, , . , Fast Ethernet , . 10 , 10 . , . , 200 ., . , , . 8.16 Fast Ethernet, . Fast Ethernet . I : 4/5, 8/6. II - . , I 100 /, II . I , .
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100VG-AnyLAN. Ethernet :
Demand Priority, , CSMA/CD. , .
, 100VG-AnyLAN , .
- Ethernet Token Ring.
4 UTP (Unshielded Twisted Pair) 3 ( 4 -
). 25 /, 100 /. Fast Ethernet 100VG-AnyLAN , 4 .
8.17 100VG-AnyLAN. , , ( ) . . , .
. , , . 100VG-AnyLAN . ( , ..), , , . , . , . , . , .
. , , . MAC- , MAC-, . , .
100VG-AnyLAN , , , , -. - , . , .
100VG-AnyLAN Ethernet Token Ring, .
100VG-AnyLAN , 3, 4 5 , .
, 100VG-AnyLAN Fast Ethernet.
8.4.5 Gigabit Ethernet
, ? , . , . Ethernet 1000 /. , . , 802.3z. Ethernet Fast Ethernet?
Ethernet.
, CSMA/CD, , .
, Ethernet Fast Ethernet: -, 5 ( ) .
MAC , .
, -
. , 200 . 512 , . 10 /, 100 1000 . - 1000 , , 4000 , . 8/10, . , . Burst Mode.
Gigabit Ethernet :
- - ;
- - 62,5/125 220 ;
- - 50/125 500 ;
- () 75 ;
- 5.
. , 5 100 . , -, 4 , 250 /. -, , 100 .
5, 5 : -2, -1, 0, +1 +2 2,322 . 125 . , 4 , (. 8.18). .
, , -
() . DSP (Digital Signal Processor).
, .
8.5
(, ). , , () . , Ethernet , . Token Ring . , , .