Alcatel-Lucent 1643 AMS Applications And Planning Manual page 277

An SDH overview
SDH frame structure
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This section provides detailed information on the locations and functions of various
overhead bytes for each of the following SDH path and line sections:
• Regenerator Section
• Multiplex Section
• Path
Section overhead
The following table identifies the location and function of each regenerator section
overhead byte.
Bytes
A1, A2
B1
B2
Z0
D1 - D3 (=
DCC ) D4 -
R
D12 (= DCC
E1
E2
F1
K1, K2
K2
S1
M1
NU
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365-312-801R7.2
Issue 3, May 2007
Function
Frame alignment A1 = 1111 0110 ; A2 = 0010 1000 ; These
fixed-value bytes are used for synchronization.
BIP-8 parity test
Regenerator section error monitoring; BIP-8 :
Computed over all bits of the previous frame after scrambling; B1 is
placed into the SOH before scrambling;
BIP-X: (Bit Interleaved Parity X bits) Even parity, X-bit code;
first bit of code = even parity over first bit of all X-bit sequences;
Multiplex section error monitoring; BIP-24 :
B2 is computed over all bits of the previous STM-1 frame except for
row 1 to 3 of the SOH (RSOH); B2 is computed after and placed
before scrambling;
Spare bytes
Data Communication Channel (network management information
exchange)
)
M
Orderwire channel
Orderwire channel
User channel
Automatic protection switch
MS-AIS/RDI indicator
Synchronization Status Message
REI (Remote Error Indication) byte
National Usage
Alcatel-Lucent - Proprietary
See notice on first page
A-9