() ().
(.1.3), .. .
:
;
;
;
;
;
.
*-
1,2
1, 1 /
1,2
F1
D1-D12 DCC
1,2 .
S1
Z1,Z2
M1 MS
J0
13. SDH 2/.
4.1.1. 12.
12 , 2.048 /. , (PAYLOAD) 140 (1 = 8 ).
4 125 , 500 .
35 , 4 9 .
12 8.
, 0, 35, 70 105, 12, (Path Overhead, ) VC12.
4.1.2. VC12.
VC12 (PAYLOAD), 12, , (Overhead) V5, J2, Z6 Z7.
V5 - ();
J2 - VC12;
Z6 - , ;
Z7 - .
4.1.3. TU12.
TU12 - , 144 , 4 125 . , VI, V2, V3 V4 TUQH (Tributary Unit Overhead).
V4 - ;
VC12 TU12 , V2.
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4.1.5. TUG2.
TUG2 - , TU12.
, (125 ) TU12, 9 4 .
TUG2 TU12; TUG2 125 .
4.1.6. TUG3.
TUG3 - , TUG2.
, , TUG2 (125 ), 9 12 .
TUG3 TUG2. 9 86 .
4.1.7. VC4.
VC4 - , TUG3 9 (Path Overhead, POH).
VC4 , TUG3, 18 9 , (Path Overhead, POH).
16 TUG3 (125 ), 9 86 .
VC'4 ; , 125 , 9 261 .
J1 , 16 , CRC7, 15 ;
4.1.8. U4.
AU4 - , , , VC4. :
- , 261 9 , 2349 , VC4;
- , (Administrative Unit Overhead, AUOH) 9 , .
10 ; VC4 AU4. 10 0 1023.
AU4 2349 , , .
3 , . .
, 3 , , (SONET) (SDH).
, , 783 STS-1 ( SONET, 51,84 /).
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, , 0 782; . , , 0.
0 , 783 2- .
VC4 AU4 (New Data Flag, NDF).
4 , : "0110".
, , : "1001".
14. 1+1. 1, 2.
1,2 .
, , - . 1 + 1 . , n , , .