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S/UNI-QUAD
PMC-Sierra, Inc.
PM5349 S/UNI-QUAD
DATASHEET
PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
201
13
OPERATION
13.1
SONET/SDH Frame Mappings and Overhead Byte Usage
13.1.1
ATM Mapping
The S/UNI-QUAD processes the ATM cell mapping for STS-3c (STM-1) as shown
below in Figure 10. The S/UNI-QUAD processes the transport and path
overhead required to support ATM UNIs and NNIs. In addition, the S/UNI-QUAD
provides support for the APS bytes. In Figure 10, the STS-3c (STM-1) mapping
is shown. In this mapping, no stuff columns are included in the SPE. The entire
SPE is used for ATM cells.
Figure 10: ATM Mapping into the STS-3c (STM-1) SPE
Section
Overhead
(Regen.
Section)
Line
Overhead
(Multiplex
Section)
Pointer
9
bytes
261 bytes
270 bytes
9
bytes
ATM Cell
ATM Cell
ATM Cell
ATM Cell
A1 A1 A1
B1
H1 H1 H1
B2 B2 B2
J0 Z0 Z0
H3 H3 H3
K2
A2 A2 A2
H2 H2 H2
M1
STS-3c Transport Overhead
STM-1 Section Overhead
G1
B3
C2
H4
K1
S1 E2