, , () (SynchronousDigitalHierarchy - SDH). , - , , , , , . 155 / , , . , , , , .
:
1) (, ) .
2) / , . / .
3) , , . ( ) , , , . " " .
4) .
, , . , 80- , , .
. SONET - SynchronousOpticalNETwork, " ". , , .
, , . , , (-ISDN), ().
, , , , , .
STM (SynchronousTransportModule) (. 3). - STM-1 - 155 /. 4 , , . STM-4 (622 /) STM-16 (2,5 /), STM-64 (10 /).
3
STM-1 | 155 / | |
STM-4 | 622 / | |
STM-16 | 2,5 / |