PM5363 TUPP+622
TUPP+622
DATASHEET
PMC-1981421
ISSUE 4
SONET/SDH TRIBUTARY UNIT PAYLOAD PROCESSOR FOR 622 MBIT/S
INTERFACES
The tributary overhead serial interface associated with the STM-1 (STS-3)
tributary processor (STP) #1 is shown in Figure 28. The tributary path overhead
bytes in each of the STS-1 (AU3) or TUG3 streams on ID[7:0] are individually
serialized on POH[3:1]. The most significant bit of the V5 byte of the first tributary
(TU#1, TUG2 #1) of each STS-1 stream is identified by a logic high value on the
corresponding POHEN[3:1] output. All four tributary path overhead bytes (V5, J2,
Z6, Z7) are shifted out once per payload frame. Since the nominal arrival rate of
overhead is once per multiframe, each overhead byte is presented on POH an
average of four times. To distinguish the first presentation of an overhead byte
from subsequent repeat presentations, the corresponding POHEN[3:1] output is
set high to mark a fresh byte and set low to mark a stale byte. POHCK provides
timing for the POH[3:1], POHFP[3:1] and POHEN[3:1] outputs. POHCK is a 9.72
MHz clock and run continuously.
Tributaries on POH are arranged in the order of transmission as in the incoming
data stream ID[7:0]. I.e., TU #1 of TUG2 #1, TU#1 of TUG2 #2, ... TU #1 of
TUG2 #7, TU #2 of TUG2 #1, ... TU #2 of TUG2 #7, TU #3 of TUG2 #1, ... TU #4
of TUG2 #7. Timeslot assignment on POH is unrelated to the configuration of the
tributary group. Timeslots for four tributaries are always reserved for any tributary
group even if it is configured for TU12, VT3 or TU2. At timeslots devoted to non-
existent tributaries, for example, tributary 2, 3 and 4 of a TUG2 configured for
TU2, POH and POHEN will be set low. The path overhead frame pulse, POHFP,
identifies the most significant bit of the first tributary (TU #1 of TUG2 #1) on POH.
In TU3 mode, the POH stream carries the nine path overhead bytes. The bytes
are shifted out twice per payload frame. The assignment of TU3 POH bytes to
lower order tributary overhead timeslots are:
TU3, J1
TU3, B3
TU3, C2
TU3, G1
TU3, F2
TU3, H4
TU3, Z3
-> TU #1, TUG2 #1, V5 and TU #3, TUG2 #1, V5
-> TU #1, TUG2 #1, J2 and TU #3, TUG2 #1, J2
-> TU #1, TUG2 #1, Z6 and TU #3, TUG2 #1, Z6
-> TU #1, TUG2 #1, Z7 and TU #3, TUG2 #1, Z7
-> TU #1, TUG2 #2, V5 and TU #3, TUG2 #2, V5
-> TU #1, TUG2 #2, J2 and TU #3, TUG2 #2, J2
-> TU #1, TUG2 #2, Z6 and TU #3, TUG2 #2, Z6
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
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PMC [ PMC-SIERRA, INC ]
