QT2022/32 - Data Sheet: DS3051
7.1.2 Path Overhead
The main function of this overhead is to provide error monitoring and connectivity checks between Path Terminat-
ing Equipment (PTE).
Table 9: Path Overhead Definitions
Value (Bits
Overhead Octet
Description
1...8)
Function
J1
Path Trace
Varies
Used to continuously send a repeating Trace Message which may be 16
octets (or 64 octets, see Section 7.3.7 Extended J1 Trace Messaging (64
bytes)) in length. This information is obtained from the Layer Management
block.
B3
Path BIP-8
Varies
Used for path error monitoring functionality. This is a bit-interleaved parity-8
code using even parity and is calculated over all bits of the previous STS-
192c SPE before scrambling.
C2
G1
STS Path Signal
Label
00011010
Varies
Identifies the construction and content of the STS-192c SPE as a 10 Gigabit
Ethernet stream.
Path Status
Used to convey back information regarding status and performance to an
originating STS-192c PTE.
Bits [1...4] - Remote Error Indication (REI) - These four bits count the
number of B3 errors that have been detected. There are nine legal values
which are 0000, 0001,0010,0011, 0100, 0101, 0110, 0111, 1000. Any other
value will be interpreted by the originating PTE as 0000.
Bits [5...8] - Remote Defect Indication (RDI) - These bits are used to convey
error information to the remote PTE.
F2
H4
Path User Channel
00000000
00000000
Unsupported, not required by IEEE 802.3aClause 50.
Unsupported, not required by IEEE 802.3 Clause 50.
Multiframe
Indicator
Z3
Z4
N1
Growth
Growth
00000000
00000000
00000000
Unsupported, not required by IEEE 802.3 Clause 50.
Unsupported, not required by IEEE 802.3 Clause 50.
Unsupported, not required by IEEE 802.3 Clause 50.
Tandem
connection
maintenance/Path
data channel
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