B-ISDN , 7- (OSI). B-ISDN : , (AAL). , ( ), .
1 - ; 2 - ; 3 - ; 4 - ; 5 - ; 6 - AAL; 7 - (AAL); 8 - AAL; 9 - ; 10 -
. , . , Ethernet, , . (SONET), (SDH), T3/E3, T1/E1 9600 /. . 45 / 3, 34 / 3, 155 / 3/STM-1, OC-12/STM4.
, : (physical medium dependent, PMD) (transmission convergence, ). PMD , , , , .. , SONET PMD. . (), .
1 - 53 ; 2 - 5 ; 3 - 48 ; 4 - ; 5 - ; 6 - ; 7 - ; 8 - ; 9 - ; 10 - ; 11 - ; 12 - (); 13 - UNI; 14 - ; 15 - ; 16 - ; 17 - ; 18 - ; 19 - ; 20 - (); 21 - NNI
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B-ISDN.
.
. . 5 48 . . , . . , , , , , . , 24- IPX FastPacket.
: - (user-network interface, UNI) - (network-network interface, NNI). UNI . UNI (customer premises equipment, ), , . NNI () . NNI .
, UNI NNI, (VPI) (VCI) . VPI , VCI . VPI VCI .
B-ISDN.
.
(ATM adaptation layer, AAL) , . , , , , ( , - , ..). AAL 48- , . . , .
AAL 1 - , , , , , .
AAL 2 - , , , , , .
AAL 3/4 - , , (), , SMDS .
AAL 5 - , , (), , .25 .
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1 - ; 2 - ; 3 - ; 4 - ; 5 -
AAL : (convergence sublayer, CS) (segmentation and reassembly sublayer, SAR). , (convergence sublayer protocol data units, CS-PDU). CS-PDU 48 , 48 .