. , . . .
(. 5.21) [77] SDH , , .
. , -, PRC. 285
( 1) , . . , D. ( 2) , . . D, . , , . 5.4.
PRC, 2048 | ||
STM-N | STM-N | |
STM-N | STM-N D | |
D | STM-N | STM-N |
, , , , D SETS (Synchronous Equipment Timing Source) . D, ( ), PRC Dont use. , D R D.
47. SDH. .
MSOH 2. STM-N BIP-24. 2. S3, .. . , BIP-24 MST : " " (SD) " " (BER). BER 10-3. SD 10-5-10-9.
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1 - . ( ) .
2 - . , RSOH. .
48. sdh
. SDH .
SDH , , PDH . , , .. , . SDH - SMUX, , . , , SDH : /.
TM SDH , PDH SDH (.3.1.). , .. , , .. .
/ ADM , (.3.1.). / . , , ADM , ("" "") . , ( ) . ADM .
49. sdh -
, - . (.3.14) . , ITU-T G.957 ITU-T G.958.
. 3.14. SDH "-" .
SDH , , , "" (backbone) (mush) , () , . SDH , . .
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50. . .
( , 1+1 ), ( , , ). , , , .
( ) ( ). , 1+1, .