PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 111

• Manufacturer Part Number: PM5366-PI
• Description: HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER AND M13 MULTIPLEXER
• Manufacturer: PMC-Sierra, Inc.

PRELIMINARY
DATASHEET
PMC-2010672
9.25 Receive Tributary Bit Asynchronous Demapper (RTDM)
PROPRIETARY AND CONFIDENTIAL
The tributary trace message of each tributary is extracted form the J2 (J1 in TU3
mode) byte. It is written to the internal buffer corresponding to the tributary. The
internal buffer may behave as a simple circular buffer, or optionally, be
synchronized to the framing pattern embedded in the message. For a 16-byte
trail trace identifier, the first byte is identified by a logic one in the most significant
bit. For a 64-byte tributary trace message, the last two bytes are set to the ASCII
characters for carriage-return (CR) and linefeed (LF).
An extracted message is declared the accepted message, if it is received
unchanged for 3 multiframes. The accepted message is compared with the
locally provisioned expected message. A tributary trace identifier mismatch
alarm (TIM) is asserted when the accepted and expected messages differ.
Conversely, TIM is negated when the messages are identical. An interrupt is
optionally generated upon a change in the TIM state. Messages of all-zeros
bytes cannot become accepted and, therefore, have no effect on the TIM state.
The RTTB also monitors for tributary trace unstable conditions. Each time a
tributary trace message that is received differs from the previous message, the
unstable counter is incremented by one. The tributary trace unstable alarm (TIU)
is asserted when the unstable counter reaches eight. The unstable counter is
cleared and the unstable alarm negated when the extracted message remains
unchanged for enough multiframes to meet the acceptance criteria. An interrupt
is optionally generated upon a change in the TIU state.
Each one of three Receive Tributary Demappers (RTDM) demaps up to 28 T1 or
21 E1 bit asynchronous mapped signals from an STS-1 SPE, TUG3 within a
STM-1/VC4 or STM-1 VC3 payload. The bit asynchronous T1 mapping consists
of 104 octets every 500 µs (2 KHz) and is shown in Table 3. The bit
asynchronous E1 mapping consists of 140 octets every 500us and is shown in
Table 4.
ISSUE 1
99
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
AND M13 MULTIPLEXER
PM5366 TEMAP-84