SONET / SDH Technical Summary
What is SONET & SDH?
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SONET and SDH are a set of related standards for synchronous data transmission over fiber optic networks. SONET is short for Synchronous Optical NETwork and SDH is an acronym for Synchronous Digital Hierarchy. SONET is the United States version of the standard published by the American National Standards Institute (ANSI). SDH is the international version of the standard published by theInternational Telecommunications Union (ITU). |
SONET/SDH Digital Hierarchy
Optical Level
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Electrical Level
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Line Rate (Mbps)
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Payload Rate (Mbps)
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Overhead Rate (Mbps)
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SDH Equivalent
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OC-1
|
STS-1 |
51.840 |
50.112 |
1.728 |
– |
OC-3
|
STS-3 |
155.520 |
150.336 |
5.184 |
STM-1 |
OC-9
|
STS-9 |
466.560 |
451.008 |
15.552 |
STM-3 |
OC-12
|
STS-12 |
622.080 |
601.344 |
20.736 |
STM-4 |
OC-18
|
STS-18 |
933.120 |
902.016 |
31.104 |
STM-6 |
OC-24
|
STS-24 |
1244.160 |
1202.688 |
41.472 |
STM-8 |
OC-36
|
STS-36 |
1866.240 |
1804.032 |
62.208 |
STM-13 |
OC-48
|
STS-48 |
2488.320 |
2405.376 |
82.944 |
STM-16 |
OC-96
|
STS-96 |
4976.640 |
4810.752 |
165.888 |
STM-32 |
OC-192
|
STS-192 |
9953.280 |
9621.504 |
331.776 |
STM-64 |
ANSI SONET Standards
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The American National Standards Institute (ANSI) coordinates and approves SONET standards. The standards are actually developed by Committee T1 which is sponsored by the Alliance for Telecommunications Industry Solutions (ATIS) and accredited by ANSI to create network interconnection and interoperability standards for the United States. T1X1 and T1M1 are the primary T1 Technical Subcommittees responsible for SONET. T1X1 deals with “digital hierarchy and synchronization”. T1M1 deals with “internetworking operations, administration, maintenance, and provisioning (OAM&P). Listed below are some of the most commonly cited SONET standards available from ANSI. Refer to the ANSI web site at http://www.ansi.org for a complete list of SONET standards along with information on purchasing the documents. |
ANSI T1.105: SONET
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Basic Description including Multiplex Structure, Rates and Formats |
ANSI T1.105.01: SONET
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Automatic Protection Switching |
ANSI T1.105.02: SONET
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Payload Mappings |
ANSI T1.105.03: SONET
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Jitter at Network Interfaces |
ANSI T1.105.03b: SONET
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Jitter at Network Interfaces – DS1 Supplement |
ANSI T1.105.04: SONET
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Jitter at Network Interfaces – DS3 Wander Supplement |
ANSI T1.105.05: SONET
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Data Communication Channel Protocol and Architectures |
ANSI T1.105.06: SONET
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Tandem Connection Maintenance |
ANSI T1.105.07: SONET
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Physical Layer Specifications |
ANSI T1.105.09: SONET
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Sub-STS-1 Interface Rates and Formats Specification |
ANSI T1.119: SONET
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Network Element Timing and Synchronization |
ANSI T1.119.01: SONET
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Operations, Administration, Maintenance, and Provisioning (OAM&P) – Communications: OAM&P Communications Protection Switching Fragment |
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ITU-T SDH Standards
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The International Telecommunications Union (ITU) coordinates the development of SDH standards. ITU was formerly known as the CCITT. It is sponsored by the United Nations and coordinates the development of telecommunications standards for the entire world. Listed below are some of the most commonly cited SDH standards available from ITU. Refer to the ITU web site at http://www.itu.int for a complete list of SONET standards along with information on purchasing the documents. |
ITU-T G.707
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Network Node Interface for the Synchronous Digital Hierarchy (SDH) |
ITU-T G.781
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Structure of Recommendations on Equipment for the Synchronous Digital Hierarchy (SDH) |
ITU-T G.782
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Types and Characteristics of Synchronous Digital Hierarchy (SDH) Equipment |
ITU-T G.783
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Characteristics of Synchronous Digital Hierarchy (SDH) Equipment Functional Blocks |
ITU-T G.803
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Architecture of Transport Networks Based on the Synchronous Digital Hierarchy (SDH) |