S3033 AMCC (Applied Micro Circuits Corp), S3033 Datasheet - Page 2

• Manufacturer Part Number: S3033
• Description: Bicmos Lvpecl Clock Generator Sonet/sdh/atm Oc-12 Transmitter And Sonet/sdh/atm Oc-3/oc-12 Transceiver
• Manufacturer: AMCC (Applied Micro Circuits Corp)

SONET OVERVIEW
Synchronous Optical Network (SONET) is a stan-
dard for connecting one fiber system to another at
the optical level. SONET, together with the Synchro-
nous Digital Hierarchy (SDH) administered by the
ITU-T, forms a single international standard for fiber
interconnect between telephone networks of differ-
ent countries. SONET is capable of accommodating
a variety of transmission rates and applications.
The SONET standard is a layered protocol with four
separate layers defined. These are:
• Photonic
• Section
• Line
• Path
Figure 2 shows the layers and their functions. Each
of the layers has overhead bandwidth dedicated to
administration and maintenance. The photonic layer
simply handles the conversion from electrical to opti-
cal and back with no overhead. It is responsible for
transmitting the electrical signals in optical form over
the physical media. The section layer handles the
transport of the framed electrical signals across the
optical cable from one end to the next. Key functions
of this layer are framing, scrambling, and error moni-
toring. The line layer is responsible for the reliable
transmission of the path layer information stream
carrying voice, data, and video signals. Its main
functions are synchronization, multiplexing, and reli-
able transport. The path layer is responsible for the
actual transport of services at the appropriate signal-
ing rates.
Data Rates and Signal Hierarchy
Table 1 contains the data rates and signal designa-
tions of the SONET hierarchy. The lowest level is the
basic SONET signal referred to as the synchronous
transport signal level-1 (STS-1). An STS- N signal is
made up of N byte-interleaved STS-1 signals. The
optical counterpart of each STS- N signal is an opti-
cal carrier level- N signal (OC- N ). The S3035 chip
supports OC-3 and OC-12 rates (155.52 and 622.08
Mbit/s).
2
S3035
SONET/SDH/ATM OC-3/12 TRANSCEIVER W/CDR
Table 1. SONET Signal Hierarchy
Frame and Byte Boundary Detection
The SONET/SDH fundamental frame format for
STS-12 consists of 36 transport overhead bytes fol-
lowed by Synchronous Payload Envelope (SPE)
bytes. This pattern of 36 overhead and 1044 SPE bytes
is repeated nine times in each frame. Frame and byte
boundaries are detected using the A1 and A2 bytes
found in the transport overhead. (See Figure 3.)
For more details on SONET operations, refer to the
Bellcore SONET standard document.
Figure 2. SONET Structure
Payload to
SPE mapping
Maintenance,
protection,
switching
Functions
Scrambling,
framing
Elec.
STS-1
STS-3
STS-12
STS-24
STS-48
Optical
transmission
End Equipment
STM-16
STM-1
STM-4
STM-8
ITU-T
Photonic layer
Section layer
Line layer
Path layer
Optical Data Rate (Mbit/s)
OC-1
OC-3
OC-12
OC-24
OC-48
Fiber Cable
April 12, 2000 / Revision D
51.84
155.52
622.08
1244.16
2488.32
Photonic layer
Section layer
Line layer
Path layer
End Equipment
(Embedded Ops
Layer Overhead
Channel)
576 Kbps
192 Kbps
0 bps