FDDI , () (Rx) . 4/5, 5- . , (J, , , Idle...), . : MLT-3 , NRZI . 100 / 125 .
, , . . . Token Ring, , FDDI . 0,01 %. , . , , , . (9000 45 000 ) 4-5 .
:
MMF-PMD (Multi Mode Fiber), . 2 . , PMD.
SF-PMD (Single Mode Fiber) . 40-60 .
LCF-PMD (Low Cost Fiber), 500 .
PMD STP 1 UTP 5, RJ-45. , 100 .
1300 , MMF, SMF LCF , . ( ) 11 , , .
FDDI , . . 13 , . :
DAS (Dual Attached Station) ( , );
SAS (Single Attached Station) ( );
DAC (Dual Attached Concentrator) , ( ) .
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SAC (Single Attached Concentrator) , .
(SAS) (DAS) (. 14) . DAS, , , . , Pri_In, Pri_ut, , . Sec_InSec_Out . Pri_InSec_ut Sec_InPri_Out. SAS, , . In Out . , .
. 13. FDDI
. 14. :
(SAS), (DAS)
(S) (DA) (. 15). / . DAC SAS SAC , SAC () . , , (null-attachment concentrator).
. 15. : (SAC), (DAC)
(repeater) , .
.
(bypass switch) (dual bypass switch), . ( 16). , . , .
, :
( SM) . . .
, , , ( 2,5 ).
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, , , , . , , , . , .
(coupler) , / , .
4 :
, ( );
, ( );
(master ) . SAS SAC;
S (slave ) . .
:
;
S.
. 7. V (Valid) , (Undesirable), . X. SMT , . (dual homing) , (connection Policy). ( ), ( ).
7.
FDDI
FDDI, , FDDI MIC (Media Interface Connector). , , , , , (. 17). . MIC ST SC.
. 17. FDDI MIC:
,
(TP-PMD) ( S). RJ-45, (. 8) 568/568. , (. 18), Ethernet. SDDI STP Type 1 DB-9, IBM Token Ring.
8
TP-PMD
( RJ-45)
FDDI . . , ( , ) ( , ). , . , 1000 .
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( 19). ( ), () , . , , , .
(wrapped ring) (. . 20). ( ) , . (500) : , 1000.
(. . 13). . , . . () . , , , . ( ). ( SAS). , .
, . 13, . / . , ( ) . ( ) . 1000.
(single tree) . , , . , . , , . 1000, ( ).
(single ring) SAS ( S-S). S DAS . . S-S, S-A S-B .
(dual homing) . , ( ) - . SMT - , - , . ( ). , , .
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FDDI : (token) / (MAC frame/Data frame), . 21. 5- ( 4/5 J, , ). . ( SD FS ) 9000 .
. 21. FDI: a ,
( )
:
(Preamble) , , .
SD (Starting Delimiter) , JK.
ED (Ending Delimiter) , .
FC (Frame Control) / . , , . , / (1 ); 2- 6- (1 ); : (2 ) (4 ).
DA (Destination Address) 2- 6- , .
SA (Source Address) , DA.
Info 4478 . (LLC) .
FCS (Frame Check Sequence) 4- CRC-, FC no Info. .
FS (Frame Status) (12 ), : , . .
(-), - , , , Info . FC, a FS.
Info : FDDI 802.2 FDDI SNAP (. 22), Ethernet, :
Ethernet , FDDI (, -, ).
FDDI , , Ethernet .
FDDI 802.2
FDDI SNAP
. 22. FDDI
FDDI (MAC, PHY PMD) SMT (Station Management). SMT . MAC, PMD PY, SMT . SMT , . SMT . , . SMT .
SMT Frame Services , , SMT .
SMT Management Information Base (MIB) / SNMP MIB.
(S Frame Based Management rotocols) SMT , , . , . 9.
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Connection Management , , -. :
(Entity Coordination Management) , () ( ), .
PCM (Physical Connection Management) , , .
(Connection Control Element) , .
PCM , .
Ring Management - -:
TTRT.
-.
.
MAC ( ).
9
FDDI
. PCM . . 23. - ( - ).
23.
( , ), :
Break State. , , Quiet . , , . Quiet Line.
Quiet Line State, Quiet, . , Break State.
Connect State Halt, .
Halt State Next State.
Next State/Signal State (, , S ) .
Idle Line State , Next State Signal State. , Idle. Next State, Idle . Signal State. Halt Master .
Link Confidence Test . MAC ( ), . , -. Join State.
Join State (Active State) .
, , . 19. .
, , OTRT (Operational Token Rotation Time).
, TRT (Token Rotation Timer). TRT, TTRT (Target Token Rotation Time). TRT .
, Claim Frame, TRT. . TRT , , . TRT, T_0PR.
, ( ), T_OPR. . T_OPR, TRT ( ). (nonrestricted token).
. , .
. ( ), -- (beaconing), ( ). , , . , . , , , . , , , . , . , .
( ), . , .