, SDH, () = 2,048. D , , , . , (. 4.14), . (), ( ), , . , , , ( ). () , , .. , . 7.1
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7.1
7.1, (, ). , () () , () ( 7.1). , 15÷20. , . Q SSM (Sinchronisation Status Massages, ITU-T G.704). SSM S1 STM-1 [ ]. 7.1.
7.1 - SSM
5-8 S1 | |||
(,PRC),δf =10-11 | G.811 | ||
(),δf =10-9 | G.812T | ||
,δf =10-8 | G.812L | ||
, δf=10-6 (SETS) | G.813 | ||
(DNU} | |||
{RES) | 1.3,5,7.9 10,12,14 | **** |
, , , () 2.048 δf =10-11 ( Q=2, 7.1). 1 ( 3.2 3.3), . , ( 3.1), Q=4, Q=8. 2. , , , . Q=11(Sinchronous Equip Timing Source, SETS, .) . , . ( , , ), (DNU) Q=15 ( 7.1). 1 2 . , , 3. , , . , . (, 1- 4 , 2 - 5 , 3 - 2 ). , Q2, (W), , (E), , .. 7.2
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7.2 -
w | E | SETS | PRS () | ||||
------------------ ------------------ (1.2,3) | |||||||
7.2, (). 2.3.
1., . ( ), ( 7.3).
7.3 -
Q | STM-4 | |||
T3 | ||||
T3 | ||||
(1) | T2 | |||
S4 | 4 ( .), 5 ( .) | 11 | ||
S4 W | 1,2,3 | 2,4,8 | 11 | |
(1) | 2 | |||
S4 W | 5 ( .) | 12 | ||
S4 W | 1,2,3 | 2,4,8 | 11 | |
(1) | 2 | |||
S4 E | T12 |
. 1 Q2, SETS (δf=10-9) - 2 Q4, 1 - 3 Q8, ., S4 - 4, Q8, . - 5 Q8. . 1, 2, 3 , ., S4 W. 4 , - .. ., ., S4 W, 4,Q8 S4 E, 5, Q8 .
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7.2. S4 . , . , DNU ( ). 1,2.3, DNU, 4 . , 5 . DNU. , SETS/(δf=10-6).