S/UNI®-JET Data Sheet
Released
Overhead Field
Growth:
Transmit Operation
Receive Operation
the RPOH pin.
nominally programmed with all
zeros. Access to these octets is
provided by the PLCP transmit
overhead access port.
F1:
This octet is unused and the value
inserted in this octet is controlled
by an internal register or by TPOH
pin.
This octet is ignored and is extracted on the
RPOH pin.
User Channel
B1:
This octet contains an 8-bit
The bit interleaved parity is calculated for the
current frame and stored. The B1 octet
contained in the subsequent frame is extracted
and compared against the calculated value.
Differences between the two values provide an
indication of the end-to-end bit error rate.
These differences are accumulated in a
counter in the CPPM block.
interleaved parity (BIP) calculated
across the entire PLCP frame
(excluding the A1, A, Pn octets
and the trailer). The B1 value is
calculated based on even parity
and the value inserted in the
current frame is the BIP result
calculated for the previous frame.
Bit Interleaved
Parity
G1:
Path Status
The first four bit positions provide
The G1 byte provides the PLCP FEBE function
and is accumulated in an a counter in the
CPPM block. PLCP yellow alarm is detected or
removed when the yellow bit is set to logic one
or zero for ten consecutive frames. The yellow
alarm state and the link status signal state are
contained in the SPLR Status Register.
a PLCP FEBE function and
indicates the number of B1 errors
detected at the near end. The
FEBE field has nine legal values
(0000b-1000b) indicating between
zero and eight B1 errors.
The fifth bit position is used to
transmit PLCP yellow alarm. The
last three bit positions provide the
link status signal used in IEEE-
802.6 DQDB implementations.
Yellow alarm and link status signal
insertion is controlled by the
internal registers or by TPOH pin.
M1, M2:
Control Information
These octets carry the DQDB layer These octets are ignored and are extracted on
management information. Internal
register controls the nominal value
inserted in these octets. These
octets are unused in ATM Forum
T3 UNI 3.0 specification.
the RPOH pin.
C1:
The coding of this octet depends
on the PLCP frame format. For
DS1 and E3 PLCP formats, this
octet is programmed with all zeros.
Interprets the trailer length according to the
selected PLCP frame format and the received
C1 code.
Cycle/Stuff Counter
For the DS3 PLCP format, this
octet indicates the number of stuff
nibbles (13 or 14) at the end of
each PLCP frame. The C1 value is
varied in a three frame cycle
where the first frame always
contains 13 stuff nibbles, the
second frame always contains 14
nibbles, and the third frame
contains 13 or 14 nibbles. The
stuffing may be varied by a nibble
so that the PLCP frame rate can
be locked to an external 8 kHz
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990267, Issue 3
265
PMC [ PMC-SIERRA, INC ]
