PM5364 pmc-sierra, PM5364 Datasheet - Page 125

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

10.6.7
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
VT/TU Payload Aligner (VTPA)
When configured for SONET compatible operation, the VT/TU Payload Aligner (VTPA)
generates the tributary payload pointers for the outgoing STS-12 data stream. Each of the seven
tributary groups (VT groups) per STS-1 stream may be independently configured to accept any
of the four tributary types (VT1.5, VT2, VT3, and VT6).
Similarly, when configured for SDH compatible operation, the VTPA generates the tributary
payload pointers in the VC3s or the TUG3s in a VC4 of the outgoing STM-4 data stream. Each
of the seven tributary unit group twos (TUG2s) in a TUG3 or VC3 may be independently
configured to accept any of the three tributary types (TU11, TU12, and TU2). Alternately, the
VTPA can accept an incoming VC3 mapped into an AU3 or a TU3 mapped into a TUG3 while
processing the payload pointer of a single outgoing TU3 mapped into a TUG3.
The VTPA aligns the outgoing tributary multiframe to an equipment reference. The alignment is
accomplished by calculating the tributary payload pointer values based on the status of the
elastic store buffer. The VTPA translates incoming STS/AU pointer justifications to tributary
pointer resulting in all VT/TUs being located in fixed columns of the transport frame. It
provides software configurable offset between the payload frame boundaries (J1) and the H3
byte of the transport overhead (High Order H1, H2 pointer value = 0 or 522). It aligns the
synchronous payloads of an STS-12/STM-4 byte serial stream to a new transport frame
reference (J0). It inserts valid high order pointer bytes (H1, H2), framing bytes (A1, A2).
Incoming tributary pointer justifications may be attenuated or optionally translated immediately
into outgoing tributary pointer justification events on a per-tributary basis. Outgoing pointer
justifications may be strictly limited to once per three multiframes. The VTPA will optionally
generate interrupts on generating an outgoing pointer justification. Per tributary performance
monitoring is also supported via positive and negative justification counts and a performance
monitoring interface. Incoming STS/AU pointer justifications have the same effect as a tributary
pointer justification on one of the tributaries in the incoming data stream. Of the tributaries
carried in the incoming data stream, the one tributary affected depends on the relative phase of
the incoming STS-1 frame and the incoming SPE. The STS/AU pointer justification is
attenuated depending on whether the affected tributary is configured to attenuate incoming
pointer events.
The VTPA uses an elastic store to accommodate the differing data rates on the incoming and
outgoing streams. Interrupts are optionally generated when the tributary elastic store overflows
or underflows. The VTPA provides optional insertion of tributary path AIS or tributary idle
(unequipped; the idle pattern is configurable) and will insert tributary path AIS on any
tributaries with an AIS condition. The VTPA can be configured to insert a new BIP2 value into
the V5 byte (non-TU3 mode; BIP8 into the B3 byte for TU3 mode). The VTPA can also insert
inverted new data flag fields, which can be used to diagnose downstream pointer processing
elements.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
125