PM5364 pmc-sierra, PM5364 Datasheet - Page 105

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

10.5.3
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
A stable trail trace byte is declared when an identical byte is received for 48 consecutive frames.
An unstable trail trace byte is declared when one or more erroneous bytes are detected in three
consecutive 16 byte windows. The first window starts on the first erroneous byte.
The RTTP provides an interrupt output to indicate any change in the status of section/path trace
identifier unstable (TIU) and section/path trace identifier mismatch (TIM). An internal register
can be read to identify the interrupt source. Each interrupt source is individually maskable.
Note: The RTTP algorithm for Trace Identifier Mismatch (TIM) detection is not compliant with
the new R6-160 recommendation put forth in the 2000 issue of Telcordia's GR-253. R6-160
states 'A change in the phase of an incoming STS path trace string shall cause the STS PTE to
consider, at most, one sample to be mismatched for the purposes of detecting and terminating
TIM-P defects.'
The RTTP algorithm complies with this if the phase change happens to drop one or more bytes.
However, the algorithm is non-compliant if the phase change happens to repeat one or more
bytes. Instead, the RTTP will count a message longer than the expected length as two
mismatched samples.
Transmit High Order Path Processor (THPP_R)
The THPP_R processes the SONET path or SDH high order path of an STS-12/STM-4 8-bit
serial stream at 77.76 MHz. Four THPP_R’s are used to process an STS-48/STM-16 32-bit
parallel stream at 77.76 MHz. The THPP_R is used to optionally insert the POH bytes and fixed
stuff bytes.
The THPP_R can insert the path overhead of any combinations of STS-1/3c/12c or VC-3/4/4-4c
payloads of an STS-12/STM-4 stream. The path overhead bytes can be inserted serially in the
THPP_R. They can also be extracted from the register set and inserted in the outgoing byte
stream. Path overhead byte insertion may be optionally disabled for specific bytes by toggling
the THPP_R PAIS input, to indicate that the overhead byte is already in the incoming byte
stream. The THPP_R generates the HTPOHRDY portion of the EV5_HTPOHRDY pin output.
The THPP_R calculates and inserts the path BIP-8 (B3) byte for each constituent SPE/VC-n
payload of the input stream. An externally generated BIP-8 code can be combined with the
calculated BIP-8 code to support the processing of STS-48c/STM-16c frames, or possibly
higher bandwidth concatenated frames. The values shifted in on the path overhead serial input
stream during the B3 byte position may be used as an error mask. The H4 read from the serial
POH input may also be used as an error mask. These values may be exclusive OR’ed with the
calculated B3 value and the H4 byte in the incoming stream to selectively corrupt one or more
bits in the resulting stream. It is also possible to invert all the B3 bits, or all the H4 bits via
register bits.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
105