PM5380-BI PMC-Sierra, Inc., PM5380-BI Datasheet - Page 381

• Manufacturer Part Number: PM5380-BI
• Description: Network Interface, SATURN User Network Interface (8x155) Telecom Standard Product
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC- 2010299, Issue 2
13.1.3
13.1.4
APS Interface Mapping
The APS serial interfaces are used to pass SONET/SDH STS-3c/STM-1 path information
between two S/UNI-8x155 devices using four 622.08 Mbit/s STS-12/STM-4 interfaces. Each
APS interface passes the path overhead and payload of four channels transparently over the
link. The section overhead contains valid A1, A2, B1, D1, D2 and D3 bytes. The Line
overhead is invalid. Figure 17 shows the mapping.
When the APS interface is carrying a transmit path being bridged, the pointer is determined by
the source Transmit Path Overhead Processor (TPOP). The path overhead is inserted by the
source TPOP and is passed transparently across the APS interface.
When the APS interface is carrying a receive path being protected, the pointer is determined by
the receive pointer value and the frequency offset between the reference clock REFCLK and the
receive serial interface. The STAL blocks perform pointer manipulation to ensure the payload
and path overhead are passed transparently.
Figure 17 APS Mapping into the STS-12/STM-4 SPE
Transport and Path Overhead Bytes
Under normal operating conditions, the S/UNI-8x155 processes a subset of the complete
transport overhead present in an STS-3c/STM-1 stream. The byte positions processed by the
S/UNI-8x155 are indicated in Figure 18.
Transport
Overhead
Overhead
Pointers
Section
B3
C2
G1
F2
H4
Z3
Z4
Z5
J1
C2
G1
H4
J1
B3
F2
Z3
Z4
Z5
B3
C2
G1
H4
J1
F2
Z3
Z4
Z5
C2
G1
H4
J1
B3
F2
Z3
Z4
Z5
S/UNI®-8x155 ASSP Telecom Standard Product Data Sheet
1080 Bytes
1044 Bytes
STS-3c/STM-1 Path Payload
261 Bytes
Payload
Bytes
9
Released
381