QT2022/32 - Data Sheet: DS3051
The QT2032 implements the logic that detects when the far-end transmit side sends a pointer that does not follow
the rules of pointer generation (ANSI- T1.105-1999 section 9.1.5 page 25).
The Pointer process will also generate the LOP-P signal as follows:
Either the logic received 8 consecutive frames with a pointer different than a valid pointer (active pointer) and none
of the received pointer triggered:
1. Positive stuff
2. Negative stuff
3. NDF pointer change
4. AIS-P
or the logic received 8 consecutive frames with NDF set 1001.
The B2 octets (192 bytes) are extracted from the incoming WIS frame. The B2 octets are stored and compared
with the calculated B2 octets of the previous frame. The B2 check performs the B2 octet calculation of the incoming
WIS frame and also performs the comparison between the calculated B2 octets and the received B2 octets
extracted from the incoming frame. The function of each B2 octet is a bit-interleaved parity 8 code using even par-
ity. Each of the 192 B2 bytes represents the BIP parity of each of the 192 STS-1 in the previous frame, with Section
Overhead excluded.
The B2 check also implements a counter to convey the count of errors detected by the Line B2 bytes. The count
has 256 legal values (0 to 255). If greater than 255 errors are detected, a value of 255 is set. The counter is passed
to TX for the purpose of generating the M1 octet. The WIS receiver monitors M1 to count the number of remote B2
errors. The near-end 32-bit counter value is stored in Registers 2.57 & 2.58 and the far-end 32-bit counter value is
stored in 2.55 & 2.56.
7.2.8 Path Overhead Extraction and B3 Check
Path Overhead extraction extracts the J1, B3, C2 and G1 octets and also removes the Path Overhead and Fixed
Stuff from the WIS stream which does not include the Section Overhead and Line Overhead.
The J1 octet in the received WIS frames are interpreted as transporting a 16-octet continuously repeating Trace
Message. 64-octet Trace Messaging can be enabled. This Trace Message is extracted from the incoming WIS
frame stream and passed to the Station Management entity (MDIO block) via dedicated registers within the WIS
Layer Management register space (J1 RX registers). The WIS Receive process does not delineate Trace Message
boundaries or process them in any way. Extraction of valid Trace Message data begins after the WIS Receive pro-
cess has successfully synchronized to the incoming WIS frame stream. Each successive J1 octet received
thereafter is placed in a successive octet of the WIS J1 RX register set, until all J1 octets have been received, after
which the process repeats from the first octet of the register set. As the incoming Trace Message is 16 octets in
size, the contents of the WIS J1 RX register set will remain static as long as the same message is being received.
Extraction of Trace Message in this fashion is performed continuously as long as valid WIS frames are being
received.
The PLM-P (Path Loss of Label Mismatch) is generated from the C2 octet which is extracted from the incoming
frame. The PLM-P is asserted when the received STS Path Label (C2 octet of the STS Path Overhead) does not
equal that assigned to 10G Ethernet (00011010) in five consecutive frames. The PLM-P signal is passed to the
Station Management entity (MDIO block) and the WIS transmit block. The G1 octet (Path Status) is passed to the
Station Management entity (MDIO block).
The B3 octet is stored and compared with the calculated B3 octet of the previous frame. The B3 octet is calculated
for the incoming WIS frame and the comparison is performed between the calculated B3 octet and the received B3
octet extracted from the incoming frame. The function of B3 octet is a bit-interleaved parity 8 code using even par-
ity. The B3 octet is calculated from the incoming frame which excludes Section Overhead and Line Overhead.
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