PMC-Sierra, Inc.
PRELIMINARY
PM5381 S/UNI-2488
DATASHEET
PMC-2000489
ISSUE 1
SATURN USER NETWORK INTERFACE FOR 2488 MBIT/S
APS bytes, the data communication channels and provides full control and observability of the
transport and path overhead bytes through register access. Figure 19, the STS-48c (STM-16c)
mapping is shown. In this mapping, the entire SPE is used for POS Frames.
Figure 19 Packet Over SONET Mapping
4320 Bytes
4176 Bytes
Transport
Overhead
J1
B3
C2
G1
F2
H4
Z3
Z4
Z5
POS Frame
Section
Overhead
F
I
X
E
D
F
I
X
E
D
Pointer
9
POS Frame
Bytes
S
T
U
F
F
S
T
U
F
F
Line
Overhead
POS Frame
POS Frame
12.2.3 Transport and Path Overhead Bytes
Transport Overhead Bytes
A1, A2:
J0
The frame alignment bytes (A1, A2) locate the SONET frame in the STS-48c
(STM-16c) serial stream.
The J0 byte is currently defined as the STS-48c (STM-16c) section trace byte
for SONET/SDH. J0 byte is not scrambled by the frame synchronous
scrambler.
Z0:
B1:
The Z0 bytes are currently defined as the STS-48c (STM-16c) section growth
bytes for SONET/SDH. Z0 bytes are not scrambled by the frame synchronous
scrambler.
The section bit interleaved parity byte provides a section error monitoring
function.
In the transmit direction, the S/UNI-2488 calculates the B1 byte over all bits of
the previous frame after scrambling. The calculated code is then placed in the
current frame before scrambling.
In the receive direction, the S/UNI-2488 calculates the B1 code over the
current frame and compares this calculation with the B1 byte received in the
following frame. B1 errors are accumulated in an error event counter.
D1 - D3:
The section data communications channel provides a 192 kbit/s data
communications channel for network element to network element
communications.
Proprietary and Confidentail to PMC-Sierra Inc., and for its Customer’s Internal Use
434
PMC [ PMC-SIERRA, INC ]
