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, . . 6 : - , - - . , , . , , , , . . . - adaptation layer - AAL - , , , . , , . , . 126. /, , AAL (ATM adaptation layer), , -. , . , (53 ). 5 - , 48 - .
, .. "" , . . , . , (, , - , .. , ).
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, , 8/10 SONET. , , . , SONET 8/10B . , , , , , , . , , . , - . , "" , , , , .
, , . , , , , , PTI , . .
-
UNI | ||||||||||
5 | GFC | VPI | ||||||||
VPI | VCI | |||||||||
48 | VCI | |||||||||
VCI | PTI | CLP | ||||||||
HEC | ||||||||||
NNI | ||||||||||
VPI | ||||||||||
VPI | VCI | |||||||||
VCI | ||||||||||
VCI | PTI | CLP | ||||||||
HEC | ||||||||||
-, 53 :
- (5 ), , , ;
- , , ( ).
- .
UNI (user-to Network Interface -) : GFC (General Flow Control) . - . 4 . VPI (Virtual Path Indentifer ) 8 . VCI (Virtual Channal Indentifer ) 16 . PTI (Plaeload Type Indentifer . 3 . 3 .
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: . , . . , .
0- | 0 | 0 0 | |
0- | 0 | 1 1 | |
0- | 1 | 0 0 | |
0- | 1 | 1 1 | |
1 | 0 ( ) | - | |
1 | 0 ( ) | - | |
1 | 1 | - | |
1 | 1 | - |
CLP (Cell Loss Priority- ) 1 . , , . , 1, , .
HEC (Header Error Control ) 1 .
UNI .
NNI (Network Node Interface - , , Network-to Network interface -) UNI , GFC, VPI 12 . NNI () . - -, -.
UNI NNI -. VPI , -, VCI . VPI VCI .
. , 48 , .
AAL , . , . , AAL , .
AAL - / (""). / "" , . , ( ) .. , , .. ( ) , . AAL, .
AAL1 , ( , , , - ) .
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AAL2 , , , .
AAL3/4 , - .
AAL5 , .25 Frame Relay.
.