SONET

Synchronous Optical NETwork



[SONET/SDH Description ] [ SONET/SDH Standards ]
[SONET/SDH Interface ICs ] [ SONET Scrambling ]
[Home]

center>

SONET/SDH Description

SONET Synchronous Optical NETwork is an ANSI standard used in the United States. SDH Synchronous Digital Hierarchy is an ITU standard used in Europe.
Both SONET and SDH are very similar, and both transmit data over fiber optic cables. Both standards are point-to-point synchronous networks that use TDM multiplexing across a ring or mesh physical topology. The ATM standard and the FDDI use SONET as the Physical layer.
The primary difference between the SONET and SDH specifications are the basic transmission rate and some header information. SONET and/or SDH backbones replaced plesiochronous digital hierarchy (PDH) systems commonly used data multiplexing technology. T-carrier information is listed on the T1/E1 page. SONET uses pointers to compensate for frequency variations and phase variations.
Pointers allow for plesiochronous signals in Synchronous Payload Envelopes.

In the synchronous network used with SONET and SDH, all the clocks are traceable to one Stratum 1 Primary Reference Clock (PRC).
The accuracy of the clock is better than +1 in 1011.





ATIS, Alliance for Telecommunications Industry Solutions [http://www.atis.org]

SONET Tutorials International Engineering Consortium [http://www.iec.org/online/tutorials/sonet/]

SONET defines the Optical Carrier [OC] levels, and the electrical levels as Synchronous Transport Signals [STS]; refer to the table below.
There are other defined rates, but are not used and un-standard.

Common SONET/SDH Rates
Hierarchy Speed SONET [US] SDH [Europe] OCx
---- 51.84Mbps STS-1 STM-0 OC-1
Level Zero 155.52Mbps STS-3 STM-1 OC-3
Level One 622.08Mbps STS-12 STM-4 OC-12
Level Two 2488.32Mbps STS-48 STM-16 OC-48
Level Three 9953.28Mbps STS-192 STM-64 OC-192
Level Four 39813.12Mbps STS-768 STM-256 OC-768

STM: Synchronous Transport Module [An information structure supporting section layer connections]
... STM-0: 21 E1 lines
... STM-1: 63 E1 lines or 1 E4 line
... STM-4: 252 E1 lines or 4 E4 lines
... STM-16: 1008 E1 lines or 16 E4 lines
... STM-64: 4032 E1 lines or 64 E4 lines
... STM-256: 16128 E1 lines or 256 E4 lines

STM Data Frame Structure
STM-N Frame Structure

The structure of the SDH Frame is shown above. The basic SDH frame format is the Synchronous Transport Module [STM], with STM-1 as the base-level.
The SDH frame is formed by 9 rows by 270 bytes with a duration of 125uS. The first 9 bytes of each row composed of the Section Overhead.
The remaining 270 bytes form the Synchronous Transport Module payload.

STS: Synchronous Transport Signal
... STS-1: 28 DS1s or 1 DS3
... STS-3: 84 DS1s or 3 DS3s
... STS-12: 336 DS1s or 12 DS3s
... STS-48: 1344 DS1s or 48 DS3s
... STS-192: 5376 DS1s or 192 DS3s
... STS-768: 21504 DS1s or 768 DS3s

VT: Virtual Tributaries [Sub STS-1 rates]
... VT-1.5: 1.728Mbps
... VT-2: 2.304Mbps
... VT-3: 3.456Mbps
... VT-6: 6.912Mbps

SONET Data Frame Structure
SONET Frame Structure

The structure of the SONET Frame is shown above. The basic SONET frame format is the Synchronous Transport Signal [STS], with STS-1 as the base-level.
The SONET frame is formed by 9 rows by 90 bytes with a duration of 125uS.
The first 3 bytes of each row [27 bits] composed of the Transport Overhead [TOH], the section may also be seen as the Section and Line header overhead.
The remaining 87 bytes form the Synchronous Payload Envelope [SPE]. The overhead bits handle; Section Overhead, Line Overhead, STS Path Overhead, and VT Path Overhead.


SONET Standards / SDH Standards Information

SONET Synchronous Optical NETwork. ANSI standard {American National Standards Institute}:
ANSI T1.105 Telecommunications - Synchronous Optical Network (SONET) - Basic Description Including Multiplex Structures, Rates, and Formats
ANSI T1.105.01 Telecommunications - Synchronous Optical Network (SONET) - Automatic Protection Switching
ANSI T1.105.02 Telecommunications - Synchronous Optical Network (SONET) - Payload Mappings
ANSI T1.105.03- Telecommunications - Synchronous Optical Network (SONET) - Jitter at Network Interfaces
ANSI T1.105.04 Telecommunications - Synchronous Optical Network (SONET) - Data Communication Channel Protocols and Architectures
ANSI T1.105.05 Telecommunications - Synchronous Optical Network (SONET) - Tandem Connection Maintenance
ANSI T1.105.06 Telecommunications - Synchronous Optical Network (SONET) - Physical Layer Specifications
ANSI T1.105.07 Telecommunications - Synchronous Optical Network (SONET) - Sub STS-1 Interface Rates and Formats Specification
ANSI T1.105.09 Telecommunications - Synchronous Optical Network (SONET) - Network Element Timing and Synchronization
ANSI T1.119 Telecommunications - Synchronous Optical Network (SONET) - Operations, Adminstration, Maintenance, and Provisioning Communications
ANSI T1.119.01 Telecommunications - Synchronous Optical Network (SONET) - Operations, Administration, Maintenance, and Provisioning Communications - Protection Switching Fragment
ANSI T1.245 Telecommunications - Directory Service for Telecommunications Management Network (TMN) and Synchronous Optical Network (SONET)
ANSI T1.514 Telecommunications - Network Performance Parameters and Objectives for Dedicated Digital Services - SONET Bit Rates

SDH Synchronous Digital Hierarchy ITU Standard [International Telecommunication Union]
G.702 Digital hierarchy bit rates
G.703 Physical/electrical characteristics of hierarchical digital interfaces
G.704 Synchronous frame structures used at 1544, 6312, 2048, 8488 and 44 736 kbit/s hierarchical levels
G.706 Frame alignment and cyclic redundancy check (CRC) procedures relating to basic frame structures defined in Recommendation G.704
G.707 Network node interface for the synchronous digital hierarchy (SDH)
G.774 Synchronous digital hierarchy (SDH) management information model for the network element view
G.774.01 Synchronous Digital Hierarchy (SDH) performance monitoring for the network element view
G.774.02 Synchronous digital hierarchy (SDH) configuration of the payload structure for the network element view
G.774.03 Synchronous digital hierarchy (SDH) management of multiplex-section protection for the network element view
G.774.04 Synchronous digital hierarchy (SDH) management of the subnetwork connection protection for the network element view
G.774.05 Synchronous Digital Hierarchy (SDH) management of connection supervision functionality (HCS/LCS) for the network element view
G.774.6 Synchronous digital hierarchy (SDH) unidirectional performance monitoring for the network element view
G.774.7 Synchronous Digital Hierarchy (SDH) management of lower order path trace and interface labeling for the network element view
G.774.8 Synchronous Digital Hierarchy (SDH) management of radio-relay systems for the network element view
G.774.9 Synchronous Digital Hierarchy (SDH) configuration of linear multiplex section protection for the network element view
G.780 Vocabulary of terms for synchronous digital hierarchy (SDH) networks and equipment G.781 Synchronization layer functions
G.783 Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks. Replaces 1994 versions of ITU-T G.781, G.782 and G.783.
G.784 Synchronous digital hierarchy (SDH) management
G.785 Characteristics of a flexible multiplexer in a synchronous digital hierarchy environment
G.803 Architecture of transport networks based on the synchronous digital hierarchy (SDH)
G.811 Timing characteristics of primary reference clocks
G.813 Timing characteristics of SDH equipment slave clocks (SEC)
G.825 The control of jitter and wander within digital networks which are based on the synchronous digital hierarchy (SDH)
G.826 Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate
G.831 Management capabilities of transport networks based on the synchronous digital hierarchy (SDH)
G.832 Transport of SDH elements on PDH networks - Frame and multiplexing structures
G.841 Types and characteristics of SDH network protection architectures
G.842 Interworking of SDH network protection architectures
G.957 Optical interfaces for equipments and systems relating to the synchronous digital hierarchy
G.958 Digital line systems based on the synchronous digital hierarchy for use on optical fibre cables
G.810 Definitions and terminology for synchronization networks
G.811 Timing characteristics of primary reference clocks
G.812 Timing requirements of slave clocks suitable for use as node clocks in synchronization networks
G.813 Timing characteristics of SDH equipment slave clocks (SEC)
G.821 Error performance of an international digital connection operating at a bit rate below the primary rate and forming part of an integrated services digital network
G.822 Controlled slip rate objectives on an international digital connection
G.823 The control of jitter and wander within digital networks which are based on the 2048 kbit/s hierarchy
G.824 The control of jitter and wander within digital networks which are based on the 1544 kbit/s hierarchy
G.825 The control of jitter and wander within digital networks which are based on the synchronous digital hierarchy (SDH)
G.826 Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate
G.827 Availability parameters and objectives for path elements of international constant bit-rate digital paths at or above the primary rate
G.832 Transport of SDH elements on PDH networks - Frame and multiplexing structures
G.841 Types and characteristics of SDH network protection architectures
G.957 Optical interfaces for equipments and systems relating to the synchronous digital hierarchy
G.958 Digital line systems based on the synchronous digital hierarchy for use on optical fibre cables


SONET Interface IC Manufacturers



--------------------

Altera {MegaCore,Transmitter/Receiver blocks with the FPGA, Packet over SONET Controller}

'Applied Micro Circuits Corp.' {STS-12C/STS-3C POS/ATM SONET Mapper, OC-48 SONET/SDH/ATM 1:8 Receiver/Transmitter,
155 Mbit/s Quad Clock Recovery Unit, OC-3/12 SONET/SDH 8-bit Quad Transceiver. SONET/SDH/10GE/10GFC OC-192 Dual CDR with EDC for SMF XFP Applications}

Anadigics {AGC AGC Transimpedence Amplifier SONET OC-1}

Oclaro Inc. {Optical Transceiver Modules; 10GBASE-ER SONET/SDH OC-192/10GbE Multiprotocol}

Broadcom Corporation {SONET/SDH OC-48/OC-192 Chips}

Exar {Physical Layer, SONET/SDH
Mapper/Framer ICs for Carrier Grade Ethernet Services ( 10/100/1000 ), SONET/SDH and PDH(DS1/E1, DS3/E3)}

Hitachi {Fiber Optic transceiver OC-3/OC-12/OC-48, SER/DESER SONET/SDH OC-192 Low Jitter Transceivers}

LSI Corporation {STS-48 SONET/SDH Grooming Switch Family}

Maxim {SONET/SDH IC's, laser driver SDH/SONET applications up to 622Mbps}

NEC {SONET/SDH Framer IC}

NTT Electronics Corporation 'NEL' {multi-rate SONET transceiver / SDH transceiver}

NXP {SONET Transceiver IC / SDH Transceiver IC}

PMC-Sierra Inc. {SONET/SDH Transport Framer/Aggregator for OC-48 and OC-192, Payload Extractor/Aligner,
# channel STS-3c/STM-1 ATM Phy with Utopia Level 2 (16 bit) & PECL, Gigabit Ethernet to SONET Mapping Device for OC-48 applications}

Sony Semiconductor {SONET/SDH Optical Transmitter / Receiver IC Manufacturer}

TI {OC-48,24,12 SONET SDH Multi-rate Transceiver}

TranSwitch Corp. {OC-12 Ethernet over SONET Mapper, OC-48 / STM-16 Ethernet and SAN Mapper}

Vitesse Semiconductor Corp. {SONET/SDH/10GbE MUXes, DEMUXes and Transceivers}

Zarlink Semiconductor Inc {OC-48 STM-16 / OC-192 STM-64 SONET/SDH Clock Multiplier PLL, SONET/SDH Network Element PLL}

IC Semiconductor Manufacturers

Scrambling The STM-N (N = 0, 1, 4, 16, 64, 256) signal must have sufficient bit timing content at the NNI.
A suitable bit pattern, which prevents a long sequence of "1"s or "0"s is provided by using a scrambler [polynomial: 1 + X6 + X7].
The STM-N signal is scrambled with a frame synchronous scrambler, of length 127, operating at the line rate.





SONET Data Scrambling Circuit using Flip Flops, XOR gate
SONET Scrambling

Gigabit Optical Transceiver

Agilent Technologies {10 Gigabit pluggable optical transceivers}

JDS Uniphase Corporation {Transceiver, 10 GbE/FC, XFP, 1310 nm}

Intel {10Gbps XFP Optical Transceiver}

Mitsubishi Electric Corp. {10Gbps Optical Devices, XENPAK Transceiver Module}

NEC Corp. {10Gbps Optical Devices, XENPAK Transceiver Module, SC / LC Interfaces}

OpNext inc.

10G Optical Module Form Factors: [Length x Width]
SFP: 16mm x 42mm
XFP: 23.5mm x 67mm
X2: 42mm x 79mm
XPAK: 42mm x 72mm
XENPAK: 47mm x 118mm
A description of Optical Transceivers is listed on the 10G Optical Module Form Factors page


Leroy's Web Page
Home

Electronic Parts and Equipment Distributors Electronic Component Manufacturers OEM Electronic Equipment Manufacturers EDA Software Producers CAD/CAE Software Engineering Standards, EE Publications Interface/Embedded Computer Bus Electronic Engineering Design Data Engineering Reference Information.
DistributorsComponents Equipment Software Standards Buses Design Reference
Modified 2/26/12
© 1998 - 2012 All rights reserved Leroy Davis